SILICON-CONTAINING UNDERLAYERS
Methods of manufacturing electronic devices employing wet-strippable underlayer compositions comprising a condensate and/or hydrolyzate of a polymer comprising as polymerized units one or more first unsaturated monomers having a condensable silicon-containing moiety, wherein the condensable silicon-containing moiety is pendent to the polymer backbone, and one or more condensable silicon monomers are provided.
The present invention relates generally to underlayers and methods of using them, and particularly to wet-strippable silicon-containing underlayers and their use in the manufacture of electronic devices.
In conventional photolithographic processes, the resist pattern is used as a mask for pattern transfer to the substrate by suitable etching processes, such as by reactive ion etch (RIE). The continued decrease in the thickness of the resist used makes the resist pattern unsuitable as a mask for pattern transfer by RIE processes. As a result, alternate processes have been developed using three, four or more layers as a mask for pattern transfer. For example, in a trilayer process a silicon-containing antireflective layer is disposed between an underlayer/organic planarizing layer and the resist layer. Due to the alternating selectivity towards fluorine and oxygen-containing RIE chemistry these layers possess, this trilayer scheme provides highly selective pattern transfer from the resist pattern on top of the Si-containing layer into the substrate below the underlayer.
The resistance of the silicon-containing underlayer toward oxide-etch chemistry allows this layer to function as an etch mask. Such silicon-containing underlayers are comprised of a crosslinked siloxane network. The etch resistance of these materials results from the silicon content, with a higher silicon content providing better etch resistance. In current 193 nm lithographic processes, such silicon-containing underlayers contain ≥30% silicon. Such high silicon content and siloxane network structure in these materials makes their removal challenging. Fluorine-containing plasma and hydrofluoric acid (HF) can both be used to remove (or strip) these silicon-containing layers. However, both F-plasma and HF will remove not only these silicon-containing materials but also other materials that are desired to remain, such as the substrate. Wet stripping using tetramethylammonium hydroxide (TMAH) in higher concentrations, such as ≥5 wt %, can be used to remove at least some of these silicon-containing layers, but these higher concentrations of TMAH also risk damaging the substrate. Silicon-containing layers having a relatively lower amount of silicon (≤17%) can sometimes be removed using “piranha acid” (concentrated H2SO4+30% H2O2), but such an approach has not achieved commercial success with silicon-containing materials having higher silicon content.
Cao et al., Langmuir, 2008, 24, 12771-12778, have reported microgels formed by free radical copolymerization of N-isopropyl acrylamide and 3-(trimethoxysilyl)propyl methacrylate, followed by cross-linking via hydrolysis and condensation of the methoxysilyl groups. Cao et al. describe such materials as being useful in biological applications, such as controlled drug release materials, biosensors and in tissue engineering. U.S. Pat. No. 9,120,952 employs materials similar to those disclosed in the Cao et al. reference for use in chemical mechanical planarization processing.
U.S. Pat. No. 8,932,953 B2 discloses compositions for forming a silicon-containing resist underlayer, wherein the compositions contain a combination of component (i) and component (ii). In this patent, component (i) is a polymer having repeating units of formula (A) and formula (B) and being capable of generating a phenolic hydroxyl group, and component (ii) is a silicon-containing compound obtained by hydrolysis-condensation of a mixture containing at least one or more hydrolysable compounds of formula (C) and one or more hydrolysable compounds of formula (D).
That is, the compositions in U.S. Pat. No. 8,932,953 are a combination of (i) certain organic polymers having both pendent aryl moieties and pendent Si—O linkages and (ii) certain siloxane polymers, wherein the pendent aryl moieties are capable of generating a phenolic hydroxyl group. This combination of components (i) and (ii) is required in U.S. Pat. No. 8,932,953 in order to achieve a composition capable of forming a resist underlayer film not only having excellent storage stability and adhesion but also having patterning properties unchanged in a positive development and in a negative development. Films formed from the compositions of this patent are removed by etching processes.
Recent advances in the field of underlayers have provided certain silicon-containing materials that can be readily removed by wet stripping techniques. One drawback is that underlayers of such silicon-containing materials tend to suffer from dissolution or swelling upon exposure to developers such as tetramethylammonim hydroxide (TMAH) which can lead to collapse of photoresist patterns formed on these underlayers. There remains a need for silicon-containing underlayers that can be removed by wet stripping and that are more resistant to photoresist pattern collapse.
The present invention provides a composition comprising: (a) one or more solvents; (b) a condensate and/or hydrolyzate of (i) one or more condensed silicon-containing polymers comprising as polymerized units one or more first unsaturated monomers having a condensable silicon-containing moiety, wherein the condensable silicon-containing moiety is pendent to the polymer backbone, and (ii) one or more condensable silicon monomers; and (c) one or more crosslinkers free of Si—O linkages. The one or more crosslinkers are capable of reacting to form covalent bonds with the one or more silicon-containing polymers.
Also provided by the present invention is a composition comprising: (a) one or more solvents; (b) one or more condensed polymers having an organic polymer chain having pendently-bound siloxane moieties; and (c) one or more crosslinkers free of Si—O linkages.
The present invention further provides a method comprising (a) coating a substrate with any of the compositions described above, to form a coating layer; (b) curing the coating layer to form a polymeric underlayer; (c) disposing a layer of a photoresist on the polymeric underlayer; (d) pattern-wise exposing the photoresist layer to form a latent image; (e) developing the latent image to form a patterned photoresist layer having a relief image therein; (f) transferring the relief image to the substrate; and (g) removing the polymeric underlayer by wet stripping. The present polymeric underlayer is a cured coating comprising as polymerized units one or more condensed polymers having pendent siloxane moieties and one or more crosslinkers free of Si—O linkages.
Still further, the present invention provides a coated substrate having a cured coating layer comprising as polymerized units: (a) one or more condensates and/or hydrolyzates of (i) one or more polymers comprising as polymerized units one or more first unsaturated monomers having a condensable silicon-containing moiety, wherein the condensable silicon-containing moiety is pendent to the polymer backbone, and (ii) one or more condensable silicon monomers; and (b) one or more crosslinkers free of Si—O linkages. Alternatively, the present invention provides a coated substrate having a cured coating layer comprising as polymerized units: (a) one or more condensed polymers having an organic polymer chain having pendently-bound siloxane moieties; and (b) one or more crosslinkers free of Si—O linkages.
It will be understood that when an element is referred to as being “adjacent” to or “on” another element, it can be directly adjacent to or on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly adjacent” or “directly on” another element, there are no intervening elements present. It will be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
As used throughout this specification, the following abbreviations shall have the following meanings, unless the context clearly indicates otherwise: ° C.=degree Celsius; g=gram; mg=milligram; ppm=part per million by weight unless otherwise noted; μm=micron=micrometer; nm=nanometer; A=angstrom; L=liter; mL=milliliter; sec.=second; min.=minute; hr.=hour; and Da=Dalton. All amounts are percent by weight and all ratios are molar ratios, unless otherwise noted. All numerical ranges are inclusive and combinable in any order, except where it is clear that such numerical ranges are constrained to add up to 100%. “Wt%” refers to percent by weight, based on the total weight of a referenced composition, unless otherwise noted. The articles “a”, “an” and “the” refer to the singular and the plural. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Mw refers to weight average molecular weight and is determined by gel permeation chromatography (GPC) using polystyrene standards. Reported pKa values are for aqueous solutions at 25° C. which may be determined experimentally, for example, by potentiometric titration such as by using a potentiometric pH meter available from Sirius Analytical Instruments Ltd., or may be calculated, for example, by using Advanced Chemistry Development (ACD) Labs Software Version 11.02. Unless otherwise noted, all measurements reported herein are made at room temperature.
As used throughout the specification, the term “alkyl” includes linear, branched and cyclic alkyl. The term “alkyl” refers to an alkane radical, and includes alkane monoradicals, diradicals (alkylene), and higher-radicals. If no number of carbons is indicated for any alkyl or heteroalkyl, then 1-12 carbons are contemplated. The term “heteroalkyl” refers to an alkyl group with one or more heteroatoms, such as nitrogen, oxygen, sulfur, phosphorus, replacing one or more carbon atoms within the radical, for example, as in an ether or a thioether. The term “alkenyl” refers to an alkene radical, and includes alkene monoradicals, diradicals (alkenylene), and higher-radicals. “Alkenyl” refers to linear, branched and cyclic alkene radicals unless otherwise specified. The term “alkynyl” refers to an alkyne radical, and includes alkyne monoradicals, diradicals, and higher-radicals. “Alkynyl” refers to linear and branched alkyne radicals. If no number of carbons is indicated for any alkenyl or alkynyl, then 2-12 carbons are contemplated. “Organic residue” refers to the radical of any organic moiety, which may optionally contain one or more heteroatoms, such as oxygen, nitrogen, silicon, phosphorus, and halogen, in addition to carbon and hydrogen. An organic residue may contain one or more aryl or non-aryl rings or both aryl and non-aryl rings. The term “hydrocarbyl” refers to a radical of any hydrocarbon, which may be aliphatic, cyclic, aromatic or a combination thereof, and which may optionally contain one or more heteroatoms, such as oxygen, nitrogen, silicon, phosphorus, and halogen, in addition to carbon and hydrogen. The hydrocarbyl moieties may contain aryl or non-aryl rings or both aryl and non-aryl rings, such as one or more alicyclic rings, or aromatic rings or both alicyclic and aromatic rings. When a hydrocarbyl moiety contains two or more alicyclic rings, such alicyclic rings may be isolated, fused or spirocyclic. Alicyclic hydrocarbyl moieties include single alicyclic rings, such as cyclopentyl and cyclohexyl, as well as bicyclic rings, such as dicyclopentadienyl, norbornyl, and norbornenyl. When the hydrocarbyl moiety contains two or more aromatic rings, such rings may be isolated or fused. By the term “curing” is meant any process, such as polymerization or condensation, that increases the molecular weight of a material or composition. “Curable” refers to any material capable of being cured under certain conditions. The term “oligomer” refers to dimers, trimers, tetramers and other relatively low molecular weight materials that are capable of further curing. The term “polymer” includes oligomers and refers to homopolymers, copolymers, terpolymers, tetrapolymers and the like. As used herein, the terms “(meth)acrylate” and “(meth)acrylic acid” refer to both acrylate and methacrylate, and acrylic acid and methacrylic acid, respectively.
Compositions useful in the present invention comprise a condensed silicon-containing polymer (also referred to herein as a “condensed polymer”). Coatings of the present compositions, and films and underlayers formed therefrom, are wet strippable, and have reduced pattern collapse as compared to conventional wet-strippable silicon-containing underlayers. As used herein, the term “condensed polymer” refers to a condensate and/or hydrolyzate of (i) one or more polymers comprising as polymerized units one or more first unsaturated monomers having a condensable silicon-containing moiety, wherein the condensable silicon-containing moiety is pendent to the polymer backbone, and (ii) one or more condensable silicon monomers, or alternatively, a polymer having an organic polymer chain having pendently-bound siloxane moieties. As used herein, the term “condensate and/or hydrolyzate” refers to a condensation product, a hydrolysis product, a hydrolysis-condensation product, or a combination of any of the foregoing. The term “hydrolysis product” refers to both a product of partial hydrolysis or complete hydrolysis.
The present condensed polymers have an organic polymer chain (or backbone) having pendently-bound siloxane moieties. The organic polymer chain comprises as polymerized units, preferably free-radically polymerized units, one or more first unsaturated monomers having a condensable silicon-containing moiety. Upon polymerization, preferably free-radical polymerization, of the one or more first unsaturated monomers and any optional second unsaturated monomers, the resulting organic polymer chain has one or more pendent condensable silicon-containing moieties. The one or more pendent condensable silicon-containing moieties of the organic polymer chain are then condensed and/or hydrolyzed with one or more condensable silicon monomers to form the present condensed polymers having pendently-bound siloxane moieties. As used herein, the term “siloxane moieties” refers to moieties having at least one (Si—O) unit. The condensed polymers of the invention may optionally, and preferably do, have a polymer chain comprising as polymerized units one or more second unsaturated monomers. Preferably, each of the first unsaturated monomers and any second unsaturated monomers comprise one radical polymerizable double or triple bond, more preferably a radical polymerizable carbon-carbon double or triple bond, and even more preferably one radical polymerizable carbon-carbon double bond. The present condensed polymers are preferably free of repeating units of a monomer having two or more radical polymerizable double bonds.
Any unsaturated monomer having a condensable silicon-containing moiety is suitable for use as the first unsaturated monomer to form the present condensed polymers. One or more first unsaturated monomers may be used. Ethylenically unsaturated monomers having a condensable silicon-containing moiety are preferred. Preferred first unsaturated monomers are those having a condensable silicon-containing moiety of the formula (1)
*-L-SiR1bY13-b (1)
wherein L is a single bond or a divalent linking group; each R1 is independently chosen from H, C1-10-alkyl, C2-20-alkenyl, C5-20-aryl, and C6-20-aralkyl; each Y1 is independently chosen from halogen, C1-10-alkoxy, C5-10-aryloxy, and C1-10-carboxy; b is an integer from 0 to 2; and * denotes the point of attachment to the monomer. It is preferred that L is a divalent linking group. It is further preferred that the divalent linking group comprises one or more heteroatoms chosen from oxygen and silicon. A suitable divalent linking group is an organic radical having from 1 to 20 carbon atoms and optionally one or more heteroatoms. Preferred divalent linking groups have the formula —C(═O)—O-L1- wherein L1 is a single bond or an organic radical having from 1 to 20 carbon atoms. Preferably, each R1 is independently chosen from C1-10-alkyl, C2-20-alkenyl, C5-20-aryl, and C6-20-aralkyl. It is preferred that each Y1 is independently chosen from halogen, C1-6-alkoxy, C5-10-aryloxy, C1-6-carboxy, and more preferably from halogen, C1-6-alkoxy, and C1-6-carboxy. Preferably, b is 0 or 1, and more preferably b=0.
It is preferred that at least one first unsaturated monomer has the formula (2)
wherein L is a single bond or a divalent linking group; each R1 is independently chosen from H, C1-10-alkyl, C2-20-alkenyl, C5-20-aryl, and C6-20-aralkyl; each of R2 and R3 are independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, halogen, C5-20-aryl, C6-20-aralkyl, and CN; R4 is chosen from H, C1-10-alkyl, C1-10-haloalkyl, halogen, C5-20-aryl, C6-20-aralkyl, and C(═O)R5; R5 is chosen from OR6 and N(R7)2; R6 is chosen from H, C1-20 alkyl, C5-20-aryl, and C6-20-aralkyl; each R7 is independently chosen from H, C1-20-alkyl, and C5-20-aryl; each Y1 is independently chosen from halogen, C1-10-alkoxy, C5-10-aryloxy, C1-10-carboxy; and b is an integer from 0 to 2. It is preferred that L is a divalent linking group. It is further preferred that the divalent linking group comprises one or more heteroatoms chosen from oxygen and silicon. A suitable divalent linking group is an organic radical having from 1 to 20 carbon atoms and optionally one or more heteroatoms. Preferred divalent linking groups have the formula —C(═O)—O-L1- wherein L1 is a single bond or an organic radical having from 1 to 20 carbon atoms. Preferably, each R1 is independently chosen from C1-10-alkyl, C2-20-alkenyl, C5-20-aryl, and C6-20-aralkyl. It is preferred that each Y1 is independently chosen from halogen, C1-6-alkoxy, C5-10-aryloxy, C1-6-carboxy, and more preferably from halogen, C1-6-alkoxy, and C1-6-carboxy. Preferably, b is 0 or 1, and more preferably b=0. It is preferred that each R2 and R3 are independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, C5-20-aryl, and C6-20-aralkyl, and more preferably from H, C1-4-alkyl, C5-20-aryl, and C6-20-aralkyl. Yet more preferably, each R2 and R3 are independently chosen from H, methyl, ethyl, propyl, butyl, phenyl, naphthyl, benzyl, and phenethyl. R4 is preferably chosen from H, C1-10-alkyl, C1-10-haloalkyl, C5-20-aryl, C6-20-aralkyl, and C(═O)R5, and more preferably from H, C1-10-alkyl, C5-20-aryl, C6-20-aralkyl, and C(═O)R5. It is preferred that R5 is OR6. R6 is preferably chosen from H, C1-10-alkyl, C5-10-aryl, and C6-15-aralkyl. Preferably, each R7 is independently chosen from H, C1-10-alkyl, and C6-20-aryl.
Suitable first unsaturated monomers having a condensable silicon-containing moiety are generally commercially available from a variety of sources, such as Sigma-Aldrich (St. Louis, Mo.), or may be prepared by methods known in the art. Such monomers may be used as-is, or may be further purified. Exemplary first unsaturated monomers include, but are not limited to: allyl dimethoxysilane; allyl dichlorosilane; (trimethoxysilyl)methyl (meth)acrylate; (trimethoxysilyl)ethyl (meth)acrylate; (trimethoxysilyl)propyl (meth)acrylate; (trimethoxysilyl)butyl (meth)acrylate; (triethoxysilyl)methyl (meth)acrylate; (triethoxysilyl)ethyl (meth)acrylate; (triethoxysilyl)propyl (meth)acrylate; (triethoxysilyl)butyl (meth)acrylate; (trichlorosilyl)methyl (meth)acrylate; (trichlorosilyl)ethyl (meth)acrylate; (trichlorosilyl)propyl (meth)acrylate; (trichlorosilysilyl)butyl (meth)acrylate; (methyldimethoxyl)silyppropyl (meth)acrylate; vinyltriacetoxy silane; (triacetoxysilyl)propyl (meth)acrylate; 4-((trimethoxysilyl)propyl)styrene; 4-(trimethoxysilyl)styrene; and vinyltrimethoxysilane.
Preferably, the organic polymer chain of the present condensed polymers further comprises as polymerized units one or more second unsaturated monomers, where such second monomers are free of a condensable silicon-containing moiety. Preferred second unsaturated monomers are ethylenically unsaturated monomers. Preferably, the condensed polymers have an organic polymer chain further comprising as polymerized units one or more second unsaturated monomers of formula (3)
wherein Z is chosen from an organic residue having from 1 to 30 carbon atoms and an acidic proton having a pKa in water from −5 to 13, an organic residue having from 1 to 30 carbon atoms and an acid decomposable group, an organic residue having a chromophore moiety, —C(═O)R13 and CN; each of R10, R11 and R12 is independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, optionally substituted C5-20-aryl, halogen, —C(═O)R14, C6-10-aryl, and CN; each of R13 and R14 is independently OR15 or N(R16)2; R15 is chosen from H, C1-20-alkyl, optionally substituted C5-30-aryl, C6-20-aralkyl and a monovalent organic residue having a lactone moiety; and each R16 is independently chosen from H, C1-20-alkyl, and C6-20-aryl; wherein Z and R10 may be taken together to form a 5 to 7-membered unsaturated ring. Preferably, Z is chosen from an organic residue having from 1 to 30 carbon atoms and an acidic proton having a pKa in water from −5 to 13, an organic residue having from 1 to 30 carbon atoms and an acid decomposable group, an organic residue having from 5 to 40 carbon atoms and having a chromophore moiety, and —C(═O)R13. A preferred halogen is fluorine. It is preferred that each of R10, R11 and R12 is independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, halogen, —C(═O)R14, and C6-10-aryl, and more preferably from H, methyl, trifluoromethyl, fluorine, and —C(═O)R14. Preferably, each of R13 and R14 is OR15. R15 is preferably chosen from H, C1-20-alkyl, C6-20-aryl, C6-20-aralkyl and a monovalent organic residue having a lactone moiety. As used herein, the term “aryl” refers to aromatic carbocycles and aromatic heterocycles. “Optionally substituted” aryl refers to both unsubstituted and substituted aryl. “Substituted aryl” refers to any aryl (or aromatic) moiety having one or more of its hydrogens replaced with one or more substituents chosen from halogen, C1-6-alkyl, C1-6-haloalkyl, C1-6-alkoxy, C1-6-haloalkoxy, phenyl, and phenoxy, preferably from halogen, C1-6-alkyl, C1-6-alkoxy, phenyl, and phenoxy, and more preferably from halogen, C1-6-alkyl, and phenyl. Preferably, a substituted aryl has from 1 to 3 substituents, and more preferably 1 or 2 substituents. It is preferred that the present condensed polymers have an organic polymer chain further comprising as polymerized units two or more different second unsaturated monomers of formula (4). The mole ratio of the total moles of the first unsaturated monomers of formula (1)+formula (2) to the total moles of any optional second unsaturated monomers such as those of formula (3) is from 100:0 to 25:75, preferably from 95:5 to 25:75, and more preferably from 75:25 to 25:75.
Preferred monomers of formula (3) wherein Z is an organic residue having from 1 to 30 carbon atoms and an acidic proton having a pKa in water from −5 to 13 are those of formula (3a)
wherein L1 is a single bond or a divalent linking group; AM is an acidic moiety having an acidic proton and having a pKa in water from −5 to 13; each of R10a, R11a and R12a is independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, optionally substituted C6-20-aryl, halogen, —C(═O)R14a, and CN; R14a is chosen from OR15a and N(R16a)2; R15a is chosen from H, C1-20-alkyl, C5-30-aryl, C6-20-aralkyl and a monovalent organic residue having a lactone moiety; and each R16a is independently chosen from H, C1-20-alkyl, and C6-20-aryl; wherein any two of L1, R10a, R11a and R12a may be taken together with the carbons to which they are attached to form a 5 to 7-membered ring. Preferably, each of R11a and R12a is independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, optionally substituted C6-20-aryl, and halogen, and more preferably from H, C1-4-alkyl, C1-4-haloalkyl, and optionally substituted C6-10-aryl. A preferred halogen is fluorine. It is preferred that R10a is chosen from H, C1-10-alkyl, C1-10-haloalkyl, optionally substituted C6-20-aryl, and —C(═O)R14a, and more preferably from H, C1-10-alkyl, C1-10-haloalkyl, optionally substituted C6-10-aryl, and —C(═O)R14a. R14a is preferably OR15a. It is preferred that R15a is H, C1-20-alkyl, C5-30-aryl, and C6-20-aralkyl, and more preferably H. Each R16a is preferably chosen from H, and C1-20-alkyl. L1 is preferably a single covalent bond or a divalent organic radical having from 1 to 20 carbon atoms and optionally one or more heteroatoms, more preferably L1 is a single covalent bond or a divalent hydrocarbyl radical having from 1 to 20 carbon atoms and optionally one or more oxygen atoms, and still more preferably L1 is chosen from a single covalent bond, a divalent C1-20-aliphatic moiety optionally comprising one or more oxygen atoms, a divalent optionally substituted C6-20-aryl moiety, and a divalent optionally substituted C7-20-alkylaryl moiety. Suitable acidic moieties for AM have one or more acidic groups chosen from carboxylic acid, sulfonic acid, sulfinic acid, sulfamic acid, phosphonic acid, boronic acid, aromatic hydroxyl, hydroxy-hexafluoroisopropyl, and combinations and acid salts thereof, preferably from carboxylic acid, sulfonic acid, phosphonic acid, boronic acid, and combinations and acid salts thereof, more preferably from carboxylic acid, sulfonic acid, phosphonic acid, boronic acid, and combinations thereof, and still more preferably carboxylic acid. Yet more preferably, AM is chosen from —C(═O)—OH, —S(═O)2—OH, —P(═O)(OH)2, —B(OH)2, C6-20-hydroxyaryl, mercapto, and C1-12-hydroxy-perfluroralkyl, and more preferably from —C(═O)—OH, —S(═O)2—OH, —P(═O)(OH)2, —B(OH)2, C6-20-hydroxyaryl, mercapto, and C1-6-hydroxy-perfluroralkyl such as hexafluoro-iso-propanolyl, and more preferably AM is —C(═O)—OH. L1 and R10a or R11a and R12a may be taken together along with the carbons to which they are attached to form a 5- to 7-membered unsaturated ring, preferably a 5- to 6-membered unsaturated ring, and more preferably a 5- to 6-membered unsaturated carbocyclic ring. R10a and R11a or R12a and L1 may be taken together along with the carbons to which they are attached to form a 5- to 7-membered saturated or unsaturated ring, preferably a 5- to 6-membered saturated or unsaturated ring, and more preferably a 5- to 6-membered saturated or unsaturated carbocyclic ring.
Other preferred second unsaturated monomers of formula (3) are those of formula (4)
wherein ADG is an acid decomposable group; and R20 is chosen from H, C1-4-alkyl, C1-4-haloalkyl, halogen, and CN. R20 is preferably chosen from H, C1-4-alkyl, C1-4-fluoroalkyl, fluorine, and CN, more preferably from H, C1-4-alkyl, trifluoromethyl, fluorine, and CN, even more preferably from H, methyl, trifluoromethyl, fluorine, and CN, and most preferably R20 is H or methyl. In formula (4), ADG is an acid decomposable group having from 2 to 30 carbon atoms. The term “acid decomposable group”, as used herein, refers to any functional group capable of being decomposed by acid to form a different functional group having increased aqueous base solubility as compared to the acid decomposable group. Suitable acid decomposable groups include, but are not limited to, —O—C4-30-hydrocarbyl moiety where the C4-30-hydrocarbyl moiety is bonded to the oxygen atom through a tertiary carbon atom, a C2-30-hydrocarbyl moiety having an anhydride moiety, a C2-30-hydrocarbyl moiety having an imide moiety, and a C4-30-organic residue comprising an acetal functional group. Preferred acid decomposable groups are —O—C4-30-hydrocarbyl moiety where the C4-30-hydrocarbyl moiety is bonded to the oxygen atom through a tertiary carbon atom, and a C4-30-organic residue comprising an acetal functional group, and more preferably —O—C4-30-hydrocarbyl moiety where the C4-20-hydrocarbyl moiety is bonded to the oxygen atom through a tertiary carbon atom, and a C4-20-organic residue comprising an acetal functional group. As used herein, the term “acetal” also embraces “ketal”, “hemiacetal”, and “hemiketal.” Exemplary acid decomposable groups include, without limitation, —NR21R22, —OR23, and —O—C(═O)—R24, wherein R21 and R22 are each independently chosen from H, C1-20-alkyl, and C5-10-aryl; R23 is a C4-30-organic residue bound to the oxygen through a tertiary carbon (that is, a carbon that is bound to three other carbons, respectively) or a C4-30-organic residue comprising an acetal functional group; and R24 is chosen from H, C1-30-alkyl, and C5-30-aryl. Preferably, R23 has from 4 to 20 carbon atoms. It is further preferred that R23 is a branched or cyclic moiety. When R23 contains a cyclic moiety, such cyclic moiety typically has from 4 to 8 atoms in the ring, and preferably 5 or 6 atoms in the ring. R23 may optionally contain one or more heteroatoms such as oxygen. Preferably, R23 is a branched aliphatic or a cycloaliphatic moiety optionally containing one or more heteroatoms.
Preferred second unsaturated monomers of formula (4) are those of formula (4a)
wherein R23 is chosen from a C4-20-organic residue bound to the oxygen through a tertiary carbon or a C4-20-organic residue comprising an acetal functional group; and R20 is chosen from H, C1-4-alkyl, C1-4-haloalkyl, halogen, and CN. More preferably, R23 has the structure shown in formula (5a) or (5b)
wherein each of R24, R25 and R26 is independently an organic residue having from 1 to 6 carbon atoms; R24 and R25 may be taken together to form a 4 to 8 membered ring; L2 is a divalent linking group or a single chemical bond; A represents an acetal functional group; and * indicates the point of attachment to the ester oxygen. It is preferred that each of R24, R25 and R26 is independently chosen from C1-6-alkyl. When R24 and R25 are taken together to form a 4 to 8 membered ring, such ring may be a single ring or may be bicyclic, and may optionally contain one or more heteroatoms chosen from oxygen, sulfur and nitrogen, preferably oxygen and sulfur and more preferably oxygen. Preferably, R24 and R25 may be taken together to form a 5 to 8 membered ring. Suitable 4 to 8 membered rings include, but are not limited to, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, and oxabicylco[2.2.1]heptyl, preferably cyclopentyl, cyclohexyl, norbornyl, and oxabicylco[2.2.1]heptyl, and more preferably cyclopentyl and cyclohexyl. Suitable divalent linking groups include C1-10-alkylene, and preferably C1-5-alkylene. Preferably, the acetal functional group is a 5 or 6-membered ring cyclic ketal, and more preferably a cyclic ketal formed from acetone. Exemplary moieties for R23 include, without limitation: tert-butyl; 2,3-dimethyl-2-butyl; 2,3,3-trimethyl-2-butyl; 2-methyl-2-butyl; 2-methyl-2-pentyl; 3-methyl-3-pentyl; 2,3,4-trimethyl-3-pentyl; 2,2,3,4,4-pentamethyl-3-pentyl; 1-methyl-1-cyclopentyl; 1-ethyl-1-cyclopentyl; 1,2-dimethyl-1-cyclopentyl; 1,2,5-trimethyl-1-cyclopentyl; 1,2,2-trimethyl-cyclopentyl; 1,2,2,5-tetramethyl-1-cyclopentyl; 1,2,2,5,5-pentamethyl-1-cyclopentyl; 1-methyl-1-cyclohexyl; 1-ethyl-1-cyclohexyl; 1,2-dimethyl-1-cyclohexyl; 1,2,6-trimethyl-1-cyclohexyl; 1,2,2,6-tetramethyl-1-cyclohexyl; 1,2,2,6,6-pentamethyl-1-cyclohexyl; 2,4,6-trimethyl-4-heptyl; 3-methyl-3-norbornyl; 3-ethyl-3-norbornyl; 6-methyl-2-oxabicylco[2.2.1] hept-6-yl; and 2-methyl-7-oxabicylco[2.2.1]hept-2-yl. Preferably, R5 is chosen from tert-butyl; 2,3-dimethyl-2-butyl; 2,3,3-trimethyl-2-butyl; 2-methyl-2-butyl; 2-methyl-2-pentyl; 3-methyl-3-pentyl; 2,3,4-trimethyl-3-pentyl; 2,2,3,4,4-pentamethyl-3-pentyl; 1-methyl-1-cyclopentyl; 1-ethyl-1-cyclopentyl; 1,2-dimethyl-1-cyclopentyl; 1,2,5-trimethyl-1-cyclopentyl; 1,2,2-trimethyl-cyclopentyl; 1,2,2,5-tetramethyl-1-cyclopentyl; 1,2,2,5,5-pentamethyl-1-cyclopentyl; 1-methyl-1-cyclohexyl; 1-ethyl-1-cyclohexyl; 1,2-dimethyl-1-cyclohexyl; 1,2,6-trimethyl-1-cyclohexyl; 1,2,2,6-tetramethyl-1-cyclohexyl; 1,2,2,6,6-pentamethyl-1-cyclohexyl; and 2,4,6-trimethyl-4-heptyl. L2 is preferably a divalent linking group. Suitable divalent linking groups for L2 have are organic residues having from 1 to 20 atoms, and more preferably from 1 to 20 carbon atoms. Optionally, the divalent linking groups of L2 may contain one or more heteroatoms, such as oxygen, nitrogen or a combination thereof. Suitable monomers of formulae (3), (4) and (4a) may be available commercially or made by a variety of methods known in the art, such as is disclosed in U.S. Pat. Nos. 6,136,501; 6,379,861; and 6,855,475.
Other preferred monomers of formula (3) are those of formula (6)
wherein R20a is independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, halogen, and CN; and R30 is a monovalent organic residue having a lactone moiety. In formula (6), R30 is a C4-20-monovalent organic residue comprising a lactone moiety. R30 may comprise any suitable lactone moiety, and preferably comprises a 5 to 7-membered lactone, which may be optionally substituted. Suitable substituents on the lactone ring are C1-10-alkyl moieties. Suitable lactone moieties for R30 are those having formula (7)
wherein E is a 5 to 7-membered ring lactone; each R31 is independently chosen from C1-10-alkyl; r is an integer from 0 to 3; Y is a chemical bond or a divalent linking residue having from 1 to 10 carbon atoms; and * indicates the point of attachment to the oxygen atom of the ester. It is preferred that each R31 is independently chosen from C1-6-alkyl, and more preferably C1-4-alkyl. Examples of R31 are methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, and iso-butyl. Preferably, r=0 or 1. Suitable divalent linking residues for Y include, but are not limited to, divalent organic residues having from 1 to 20 carbon atoms. Suitable divalent organic residues for Y include, without limitation, C1-20-hydrocarbyl moieties, C1-20-heteroatom-containing hydrocarbyl moieties, and substituted C1-20-hydrocarbyl moieties. The term “C1-20-heteroatom-containing hydrocarbyl moieties” refers to hydrocarbyl moieties having one or more heteroatoms, such as nitrogen, oxygen, sulfur, phosphorus, within the hydrocarbyl chain. Exemplary heteroatoms include, but are not limited to, —O—, —S—, —N(H)—, —N(C1-20-hydrocarbyl)-, —C(═O)—O—, —S(═O)—, —S(═O)2—, —C(═O)—NH—, and the like. “Substituted C1-20-hydrocarbyl moieties” refers to any hydrocarbyl moiety having one or more hydrogens replaced with one or more substituents such as halogen, cyano, hydroxy, amino, mercapto, and the like. It is preferred that R30 is chosen from gamma-butyrolactone (GBLO), beta-butyrolactone, gamma-valerolactone, delta-valerolactone, and caprolactone, and more preferably, R30 is GBLO. Monomers of formula (6) are generally commercially available or may be prepared by methods known in the art.
In one preferred embodiment, the present condensed polymers have a polymer chain that further comprise as polymerized units, one or more second unsaturated monomers comprising a chromophore. Suitable chromophores are any aromatic (aryl) moiety that absorbs radiation at the wavelength of interest. Such chromophores are unsubstituted aromatic moieties, such as phenyl, benzyl, naphthyl, anthracenyl, and the like, or may be substituted with one or more of hydroxyl, C1-10-alkyl, C2-10-alkenyl, C2-10-alkynyl, and C5-30-aryl, preferably is unsubstituted or hydroxyl-substituted, and more preferably is unsubstituted. Preferably, the condensed polymer has an organic polymer chain comprising as polymerized units, one or more second unsaturated monomers of formula (3) having a chromophore moiety. Preferred chromophore moieties are chosen from pyridyl, phenyl, naphthyl, acenaphthyl, fluorenyl, carbazolyl, anthracenyl, phenanthryl, pyrenyl, coronenyl, tetracenyl, pentacenyl, tetraphenyl, benzotetracenyl, triphenylenyl, perylenyl, benzyl, phenethyl, tolyl, xylyl, styrenyl, vinylnaphthyl, vinylanthracenyl, dibenzothiophenyl, thioxanthonyl, indolyl, acridinyl, biphenyl, phenoxy-phenyl, binaphthyl, and the like, and more preferably phenyl, naphthyl, anthracenyl, phenanthryl, benzyl, and the like. Chromophores used in the present invention are preferably free of aromatic rings having a substituent of the structure *—C(Rx)2—O-Lg, wherein each Rx is independently H or a alkyl group of 1 to 15 carbons, where each Rx may be taken together form an aliphatic ring; Lg is H, an aliphatic monovalent hydrocarbon having 1 to 10 carbons, or a monovalent aromatic group, and * indicates the point of attachment to the aromatic ring.
Exemplary second unsaturated monomers include, without limitation: vinyl aromatic monomers such as styrene, α-methylstyrene, β-methylstyrene, stilbene, vinylnaphthylene, acenaphthalene, and vinylpyridine; hydroxy-substituted vinyl aromatic monomers such as hydroxystyrene, o-courmaric acid, m-courmaric acid, p-courmaric acid, and hydroxyvinylnaphthylene; carboxyl-substituted vinyl aromatic monomers such as vinyl benzoic acid; ethylenically unsaturated carboxylic acids such as cinnamic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, itaconic acid, 3-pyridine (meth)acrylic acid, 2-phenyl (meth)acrylic acid, (meth)acrylic acid, 2-methylenemalonic acid, cyclopentenecarboxylic acid, methylcyclopentenecarboxylic acid, cyclohexenecarboxylic acid, and 3-hexene-1,6-dicarboxylic acid; hydroxyaryl esters of ethylenically unsaturated carboxylic acids, such as hydroxyphenyl (meth)acrylate, hydroxybenzyl (meth)acrylate, hydroxynaphthyl (meth)acrylate, and hydroxyanthracenyl (meth)acrylate; ethylenically unsaturated anhydride monomers such as maleic anhydride, citraconic anhydride and itaconic anhudride, ethylenically unsaturated imide monomers such as maleimide; ethylenically unsaturated carboxylic acid esters such as crotonic acid esters, itaconic acid esters, and (meth)acrylate esters; (meth)acrylonitrile; (meth)acrylamides; and the like. Suitable (meth)acrylate ester monomers include, but are not limited to, C7-10-aralkyl (meth)acrylates, C1-10-hydroxyalkyl (meth)acrylates, glycidyl (meth)acrylate, C1-10-mercaptoalkyl (meth)acrylates, and C1-10-alkyl (meth)acrylates. Exemplary (meth)acrylate ester monomers include, without limitation, benzyl acrylate, benzyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, mercaptopropyl methacrylate, glycidyl methacrylate, methyl acrylate, and methyl methacrylate.
It is preferred that the present condensed polymers have an organic polymer chain comprising as polymerized units one or more first unsaturated monomers of formula (2) and one or more second unsaturated monomers of formula (3), preferably one or more first unsaturated monomers of formula (2) and two or more second unsaturated monomers of formula (3), even more preferably one or more first unsaturated monomers of formula (2) and one or more second unsaturated monomers of formula (6), and still more preferably one or more first unsaturated monomers of formula (2), one or more second unsaturated monomers of formula (6), and one or more second unsaturated monomers of formula (3) having a chromophore moiety. When the organic polymer chain of the present condensed polymers comprise as polymerized units one or more first unsaturated monomers of formula (2) and one or more second unsaturated monomers of formula (3), such monomers are present in a mole ratio of 1:99 to 99:1 of total monomers of formula (2) to total monomers of formula (3). Preferably, the mole ratio of the total monomers of formula (2) to the total monomers of formula (3) is from 95:5 to 5:95, more preferably from 90:10 to 10:90, and yet more preferably from 50:50 to 5:95. The one or more optional second unsaturated monomers may be used in an amount from 0 to three times the molar amount of the total first unsaturated monomers of formulae (1) and (2). When the present condensed polymers comprise as polymerized units a relatively higher percentage of second unsaturated monomers containing a chromophore, such polymers show reduced ability to be removed by wet stripping. It is preferred that the present condensed polymers comprise as polymerized units from 0 to 50 mol % of second unsaturated monomers containing a chromophore.
Any condensable silicon monomer may be used to form the present condensed polymers, provided that the condensable silicon monomer is different from the first unsaturated monomer having a condensable silicon moiety, and that the condensable silicon monomer condenses with the condensable silicon moiety pendently-bound to the organic polymer backbone. As used herein, the term “backbone” refers to the main polymer chain As used herein, “condensable silicon monomer” refers to a silicon monomer having one or more condensable or hydrolyzable moieties. As used herein, “condensable moiety” or “hydrolyzable moiety” refers to any moiety capable to being condensed or hydrolyzed under conditions used to form the present condensed polymers. Exemplary condensable or hydrolyzable moieties include, but are not limited to, halogens, alkoxy, carboxylate, hydroxy, enoxy, oximino, amino, and the like. Suitable condensable silicon monomers are those of formula (8)
Si(R50)p(X)4-p (8)
wherein p is an integer from 0 to 3; each R50 is independently chosen from a C1-30 hydrocarbyl moiety and a substituted C1-30 hydrocarbyl moiety; and each X is independently chosen from halogen, C1-10 alkoxy, —OH, —O—C(O)—R50, and —(O—Si(R51)2)p2—X1; X1 is independently chosen from halogen, C1-10 alkoxy, —OH, —O—C(O)—R50; each R51 is independently chosen from R50 and X; and p2 is an integer from 1 to 10. Preferably, p is an integer from 0 to 2, more preferably 0 to 1, and yet more preferably p=0. X is preferably chosen from C1-10-alkoxy, —OH, —O—C(O)—R50, and —(O—Si(R51)2)p2—X1, and more preferably from C1-10-alkoxy and —OH. X1 is preferably chosen from C1-10-alkoxy and —OH. The substituted C1-10-hydrocarbyl moiety of R50 refers to any C1-30 hydrocarbyl moiety having one or more of its hydrogens replaced with one or more substituted moieties chosen from hydroxy, mercapto, C1-20 alkoxy, amino, C1-20-alkylamino, di-C1-20-alkylamino, cyano, halogen, epoxide, —C(═O)O—R17, —C(═O)—N(R17)2, and C(═O)—O—C(═O)—R17, wherein each R17 is chosen from H and C1-20-alkyl. Suitable C1-30-hydrocarbyl moieties of R50, without limitation, C1-30-alkyl, C2-30-alkenyl, C2-30-alkynyl, C3-30-cycloalkyl, and C6-30-aryl, and preferably are C1-20-alkyl, C2-20-alkenyl, C2-20-alkynyl, C3-20-cycloalkyl, and C6-25-aryl. Silicon monomers are often referred to by the number of hydrolyzable moieties bonded to silicon in the monomer. For example, “M monomer” refers to a silicon monomer having one hydrolyzable moiety, such as monomers of formula (R50)3SiX, “D monomer” refers to a silicon monomer having two hydrolyzable moieties such as monomers of the formula (R50)2SiX2, “T monomer” refers to a silicon monomer having three hydrolyzable moieties such as monomers of the formula R50SiX3, and “Q monomer” refers to a to a silicon monomer having four hydrolyzable moieties such as monomers of the formula SiX4, wherein X and R50 in each monomer are as described above. Any of M, D, T and Q monomers may be used individually or a mixture of any of the foregoing may be used to prepare the present condensed polymers. Preferably, the condensable silicon monomer is one or more monomers chosen from formulas (8a), (8b), (8c), and (8d)
R503SiX (8a)
R502SiX2 (8b)
R50SiX3 (8c)
SiX4 (8d)
wherein each X and R50 are as described above for formula (8). It is preferred that one or more Q monomers, that is, monomers of formula (8d), are used to prepare the present condensed polymers. Such condensable silicon monomers are generally commercially available and may be used as is or may be further purified.
Condensable silicon monomers useful in forming the present condensed polymers include, without limitation, methyltrichlorosilane, methyltrimethoxysilane, emethyltriethoxysilane, methyltriacetoxysilane, ethyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriacetoxysilane, propyltrichlorosilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriacetoxysilane, hydroxypropyltrichlorosilane, hydroxypropyltrimethoxysilane, hydroxypropyltriethoxysilane, hydroxypropyltriacetoxysilane, mercaptopropyltrichlorosilane, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, mercaptopropyltriacetoxy-silane, cyclopentyltrichlorosilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, cyclopentyltriacetoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxy silane, phenyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, biphenyltrichlorosilane, biphenyltrimethoxysilane, biphenyltriethoxysilane, biphenyltriacetoxysilane, dimethyldichlorosilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiacetoxysilane, diethyldichlorosilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldiacetoxysilane, diphenyldichlorosilane, diphenyldimethyoxy-silane, diphenyldiethoxysilane, diphenyldiacetoxysilane, methylphenyldichlorosilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, methylphenyldiacetoxysilane, methylvinyldichlorosilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, methylvinyldiacetoxysilane, divinyldichlososilane, divinyldimethoxysilane, divinyldiethoxysilane, divinyldiacetoxysilane, tetrachlorosilane, tetramethoxysilane, tetraethoxysilane, and tetraacetoxysilane. Preferred curable silicon monomers are tetramethoxysilane and tetraethoxysilane.
Optionally, one or more etch selectivity improving agents may also be condensed with the one or more condensable silane monomers and the one or more polymers described above. Suitable etch selectivity improving agents are those of formula (9)
G(X2)m4 (9)
wherein, G is an element from Groups 13 to 15 of the periodic table excluding carbon and silicon; each X2 is independently halogen or OR52; each R52 is independently H or an organic group having 1 to 30 carbon atoms; and m4 is equal to the valence of G. Preferably, R52 is chosen from H, C1-10-alkyl, —C(O)—C1-10-alkyl, and C6-10-aryl, and more preferably from H, C1-10-alkyl, and —C(O)—C1-10-alkyl. G is preferably an element chosen from boron, aluminum, gallium, yttrium, germanium, titanium, zirconium, hafnium, bismuth, tin, phosphorous, vanadium, arsenic, antimony, niobium, and tantalum, more preferably from boron, aluminum, and germanium, and even more preferably G is boron. Suitable compounds of formula (9) include, but are not limited to: trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, tripentyl borate, trihexyl borate, tricyclopentyl borate, tricyclohexyl borate, triallyl borate, triphenyl borate, boron methoxyethoxide, boric acid, boron oxide; aluminum methoxide, aluminum ethoxide, aluminum propoxide, aluminum butoxide, aluminum amyloxide, aluminum hexyloxide, aluminum cyclopentoxide, aluminum cyclohexyloxide, aluminum allyloxide, aluminum phenoxide, aluminum ethoxyethoxide, aluminum dipropoxyethyl-acetoacetate, aluminum dibutoxyethyl-acetoacetate, aluminum propoxy-bis-ethyl-acetoacetate, aluminum butoxy-bis-ethyl-acetoacetate, aluminum 2,4-pentanedionate, aluminum 2,2,6,6-tetramethyl-3,5-heptanedionate, germanium methoxide, germanium ethoxide, germanium propoxide, germanium butoxide, germanium amyloxide, germanium hexyloxide, germanium cyclopentoxide, germanium cyclohexyloxide, germanium allyloxide, germanium phenoxide, and germanium ethoxyethoxide. Suitable etch selectivity improving agents are those disclosed in U.S. Pat. No. 8,951,917.
Condensed polymers of the invention may be prepared by first polymerizing the one or more first unsaturated monomers and any optional second unsaturated monomers according to methods well-known in the art to form an uncondensed polymer. Preferably, the present monomers are polymerized by free-radical polymerization, such as those procedures used for preparing (meth)acrylate or styrenic polymers. Any of a wide variety of free-radical initiators and conditions my be used. Other suitable polymerization methods of preparing the polymers include, without limitation, Diels-Alder, living anionic, condensation, cross-coupling, RAFT, ATRP, and the like. Next, one or more uncondensed polymers are subjected to conditions to condense and/or hydrolyze the condensable silicon-containing moiety to form the present condensed polymers. Such condensation and/or hydrolysis conditions are well-known in the art and typically involve contacting the one or more uncondensed polymers with aqueous acid or aqueous base, and preferably aqueous acid. For example, one or more of the present uncondensed polymers may be contacted with a composition comprising water, an acid, and optionally one or more organic solvents, with optional heating. Preferred acids are mineral acids, such as HCl. The condensed polymers of the invention may be partially condensed or fully condensed. By “partially condensed” it is meant that a portion of the condensable silicon-containing moieties present in the polymer have undergone a condensation or hydrolysis reaction. By “fully condensed” is meant that all condensable silicon-containing moieties present in the polymer have undergone a condensation or hydrolysis reaction. The present uncondensed polymers typically have a Mw of 1000 to 10000 Da, preferably from 2000 to 8000 Da, and more preferably from 2500 to 6000 Da. The present condensed polymers typically have a Mw of 5000 to 75000 Da, preferably from 10000 to 50000 Da, and more preferably from 20000 to 40000 Da. It will be appreciated by those skilled in the art that mixtures of condensed polymers may suitably be used in the present process.
In addition to one or more of the above-described condensed polymers, the present compositions further comprise one or more crosslinkers free of Si—O linkages and one or more organic solvents. Any crosslinker may be suitably used in the present coating compositions, provided such crosslinker is free of Si—O linkages and has a plurality of functional groups capable of reacting with the condensed polymer upon curing. The crosslinker has at least 2 functional groups, preferably at least 3, and more preferably at least 4, functional groups capable of reacting with the condensed polymer upon curing. Exemplary functional groups capable of reacting with the condensed polymer upon curing include, without limitation, hydroxyl groups, epoxy groups, oxetane groups, thiol groups, lactone moieties, isothiocyanate groups, anhydride moieties, maleimide moieties, carboxylic acid groups, alkynyl groups, halogens, aldehyde groups, allyl ether moieties, imine groups, unsaturated ketone moieties, and the like. Preferred functional groups are hydroxyl groups. Preferably, the crosslinker has at least 2 of the same functional group, more preferably at least 3, and even more preferably at least 4 of the same functional group. When the functional group is a hydroxyl group, such hydroxyl group may be a primary, secondary or tertiary aliphatic hydroxyl group or an aromatic hydroxyl group, and more preferably a primary aliphatic hydroxyl or a secondary aliphatic hydroxyl group. Suitable crosslinkers may be polymeric or non-polymeric. Polymeric crosslinkers useful in the present compositions may be linear, branched, star or dendritic polymers. When the crosslinker is polymeric, the functional groups capable of reacting with the condensed polymer upon curing may be terminal groups on the polymer chain or be pendently-bound to the polymer chain, or a combination thereof. Preferably, the crosslinker is a non-polymeric aliphatic polyol, a polymer having pendently bound hydroxyl groups, or a mixture thereof. As an upper limit, each terminus and/or each repeating unit of the polymeric crosslinker may have a functional group capable of reacting with the condensed polymer upon curing. Preferably, up to 50 mol %, more preferably up to 40 mol %, even more preferably up to 30 mol %, and yet more preferably from 10 to 30 mol %, of the repeating units of the polymeric crosslinker have a functional group capable of reacting with the condensed polymer upon curing. Preferred polymeric crosslinkers useful in the present invention are hydroxy-terminated alkylene oxide polymers and polymers having pendently bound hydroxyl groups. In general, weight ratio of the condensed polymer to the crosslinker is from 95:5 to 60:40, preferably from 90:10 to 70:30, more preferably from 85:15 to 70:30.
Suitable non-polymeric crosslinkers have at least 2 functional groups, preferably at least 3, more preferably at least 4, and still more preferably 4 to 6, functional groups capable of reacting with the condensed polymer upon curing. In general, non-polymeric crosslinkers have 10 or fewer functional groups capable of reacting with the condensed polymer during curing. Typical non-polymeric crosslinkers are those having an organic residue of 2 to 40, preferably 3 to 30, and more preferably 4 to 30, carbon atoms and from 2 to 10 hydroxyl groups, preferably 2 to 8 hydroxyl groups, more preferably 3 to 8 hydroxyl groups, and yet more preferably 4 to 6 hydroxyl groups. Optionally, the suitable non-polymeric crosslinkers may be alkoxylated, that is they may be reacted with, on average, less than or equal to 2 moles of alkylene oxide, such as ethylene oxide and/or propylene oxide, per hydroxyl group. By way of example, if the non-polymeric crosslinker has 4 hydroxyl groups, such as pentaerythritol, it may be reacted with up to 8 moles of alkylene oxide (that is, an average 2 moles of alkylene oxide per hydroxyl group). Exemplary non-polymeric crosslinkers are, without limitation, glycerol, trimethylol ethane, trimethylol propane, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, di(trimethylolpropane), 2-hydroxymethyl-1,3-propanediol, sorbitol, xylitol, ethoxylated glycercol having 2 to 6 moles of ethylene oxide, propoxylated glycerol having 2 to 6 moles of propylene oxide, ethoxylated trimethylol ethane having 2 to 6 moles of ethylene oxide, propoxylated trimethylol ethane having 2 to 6 moles of propylene oxide, ethoxylated trimethylol propane having 2 to 6 moles of ethylene eoxide, propoxylated trimethylol propane having 2 to 6 moles of propylene oxide, ethoxylated erythritol having 3 to 8 moles of ethylene oxide, propoxylated erythritol having 3 to 8 moles of propylene oxide, ethoxylated pentaerythritol having 3 to 8 moles of ethylene oxide, propoxylated pentaerythritol having 3 to 8 moles of propylene oxide, ethoxylated dipentaerythritol having 4 to 12 moles of ethylene oxide, propoxylated dipentaerythritol having 4 to 12 moles of propylene oxide, ethoxylated tripentaerythritol having 6 to 16 moles of ethylene oxide, propoxylated tripentaerythritol having 6 to 16 moles of propylene oxide, ethoxylated di(trimethylolpropane) having 3 to 8 moles of ethylene oxide, propoxylated di(trimethylolpropane) having 3 to 8 moles of propylene oxide, and mixtures thereof. Preferred non-polymeric crosslinkers are trimethylol propane, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, 2-hydroxymethyl-1,3-propanediol, ethoxylated trimethylol ethane having 2 to 6 moles of ethylene oxide, propoxylated trimethylol ethane having 2 to 6 moles of propylene oxide, ethoxylated trimethylol propane having 2 to 6 moles of ethylene eoxide, propoxylated trimethylol propane having 2 to 6 moles of propylene oxide, ethoxylated erythritol having 3 to 8 moles of ethylene oxide, propoxylated erythritol having 3 to 8 moles of propylene oxide, ethoxylated pentaerythritol having 3 to 8 moles of ethylene oxide, propoxylated pentaerythritol having 3 to 8 moles of propylene oxide, ethoxylated dipentaerythritol having 4 to 12 moles of ethylene oxide, propoxylated dipentaerythritol having 4 to 12 moles of propylene oxide, ethoxylated tripentaerythritol having 6 to 16 moles of ethylene oxide, propoxylated tripentaerythritol having 6 to 16 moles of propylene oxide, ethoxylated di(trimethylolpropane) having 3 to 8 moles of ethylene oxide, propoxylated di(trimethylolpropane) having 3 to 8 moles of propylene oxide, and mixtures thereof.
One class of polymeric crosslinkers useful in the present compositions are alkylene oxide polymers having C2-4-alkyleneoxy repeating units and 2 or more terminal hydroxyl groups, and polymers having pendently bound hydroxyl groups. Preferred alkylene oxide polymers have 3 or more terminal hydroxyl groups, and more preferably 4 or more terminal hydroxy groups. Exemplary alkyleneoxy repeating units are ethyleneoxy, propyleneoxy, butyleneoxy, and combinations thereof. Preferred alkylene oxide polymers are glycerol ethoxylate having an average of 3-30 ethyleneoxy units, glycerol propxylate having an average of 3-30 propyleneoxy units, trimethylolpropane ethoxylate having an average of 3-30 ethyleneoxy units, trimethylolpropane propxylate having an average of 3-30 propyleneoxy units, pentaerythritol ethoxylate having an average of 3-30 ethyleneoxy units, pentaerythritol propxylate having an average of 3-30 propyleneoxy units, pentaerythritol ethoxylate/propoxylate having an average of 3-30 ethyleneoxy units and an average of 3-30 propyleneoxy units, dipentaerythritol ethoxylate having an average of 4-30 ethyleneoxy units, dipentaerythritol propxylate having an average of 4-30 propyleneoxy units, and combinations thereof
Preferred polymeric crosslinkers useful in the present compositions are polymers having pendently bound hydroxyl groups, and preferably comprise as polymerized units one or more unsaturated monomers having a hydroxy-substituted moiety of the formula *-L3—OH, where * denotes the point of attachment to the monomer; and L3 is a C1-30-divalent linking group. Preferably, the polymeric crosslinkers having hydroxyl-substituted pendent groups comprise as polymerized units one or more monomers of formula (10)
wherein R60 and R61 are independently H, C1-10-alkyl, C6-20-aryl, C1-10-haloalkyl, halogen, or -L3-OH; R62 is H, C1-4-alkyl, C1-4-haloalkyl, halogen, CN, or -L3-OH; and L3 is a C1-30-divalent linking group. It is preferred that R60 and R61 are independently H or -L3-OH, and more preferably H. Preferably, R62 is H, C1-4-alkyl, C1-4-haloalkyl, halogen, or CN; and more preferably H or methyl. L3 is preferably a C1-30-organic residue optionally having from 1 to 10 heteroatoms. Preferred monomers of formula (10) are C2-10-hydroxyalkyl (meth)acrylates of formula (10A) and alkyleneoxy (meth)acrylates of formula (10B)
wherein R62a is H or methyl; R63 is C2-10-alkylene; R62b is H or methyl; and p4 is the average number of O—C2-3-alkylene units and is an integer from 1 to 10. Exemplary monomers of formulae (10A) and (10B) are hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methyacrylate, ethoxylated (meth)acrylate having an average of 1-10 ethyleneoxy units, and propoxylated (meth)acrylate having an average of 1-10 propyleneoxy units. Preferred polymeric crosslinkers having pendently bound hydroxy groups are those comprising as polymerized units one or more monomers of formula (10) and one or more monomers chosen from (meth)acrylic acid, C1-20-alkyl (meth)acrylates, C6-20-aryl (meth)acrylates, C7-20-arylalkyl (meth)acrylates, vinyl aromatic monomers, monomers of formula (4), and monomers of formula (6)
wherein ADG is an acid decomposable group as described above; each of R20 and R20a is independently chosen from H, C1-4-alkyl, C1-4-haloalkyl, halogen, and CN; and R30 is a monovalent organic residue having a lactone moiety as described above. Preferably, the polymeric crosslinkers comprise as polymerized units from 5 to 50 mol %, more preferably 5 to 40 mol %, even more preferably 5 to 30 mol %, and yet more preferably from 10 to 30 mol %, of monomers of formula (10). Other preferred monomers of formula (10) include hydroxystyrene and hydroxy(vinylnaphthalene).
A variety of organic solvents and water may be used in the present compositions, provided that such solvent dissolves the components of the composition. Preferably, the present compositions comprise one or more organic solvents and optionally water. Organic solvents may be used alone or a mixture of organic solvents may be used. Suitable organic solvents include, but are not limited to; ketones such as cyclohexanone and methyl-2-n-amylketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol methyl ether (PGME), propylene glycol ethyl ether (PGEE), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate (EL), methyl hydroxyisobutyrate (HBM), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as gamma-butyrolactone; ionic liquids; and any combination of the foregoing. Preferred solvents are PGME, PGEE, PGMEA, EL, HBM, and combinations thereof.
The present compositions may further comprise one or more optional components, such as cure catalysts, coating enhancers, one or more stabilizers, and the like. The amount of such optional components used in the present compositions is well within the ability of those skilled in the art.
Suitable cure catalysts include, but are not limited to, thermal acid generators, photoacid generators, photobase generators, and quaternary ammonium salts, preferably thermal acid generators and quaternary ammonium salts, and more preferably quaternary ammonium salts. A thermal acid generator is any compound which liberates acid upon exposure to heat. Thermal acid generators are well-known in the art and are generally commercially available, such as from King Industries, Norwalk, Conn. Exemplary thermal acid generators include, without limitation, amine blocked strong acids, such as amine blocked sulfonic acids like amine blocked dodecylbenzenesulfonic acid. A wide variety of photoacid generators are known in the art and are also generally commercially available, such as from Wako Pure Chemical Industries, Ltd., and from BASF SE. Suitable quaternary ammonium salts are: quaternary ammonium halides; quaternary ammonium carboxylates; quaternary ammonium sulfonates; quaternary ammonium bisulfates; and the like. Preferred quaternary ammonium salts include; benzyltrialkylammonium halides such as benzyltrimethylammonium chloride and benzyltriethylammonium chloride; tetraalkylammonium halides such as tetramethylammonium halides, tetraethylammonium halides, and tetrabutylammonium halides; tetraalkylammonium carboxylates such as tetramethylammonium formate, tetramethylammonium acetate, tetramethylammonium triflate, tetrabutylammonium acetate, and tetrabutylammonium triflate; tetraalkylammonium sulfonates such as tetramethylammonium sulfonate and tetrabutylammonium sulfonate; and the like. Preferred cure catalysts are tetraalkylammonium halides, and more preferably tetraalkylammonium chlorides. Such quaternary ammonium salts are generally commercially available, such as from Sigma-Aldrich, or may be prepared by procedures known in the art. Such optional curing catalysts are used in the present compositions in an amount of from 0 to 10% of total solids, preferably from 0.01 to 7% of total solids, and more preferably from 0.05 to 5% of total solids.
Coating enhancers are optionally added to the present compositions to improve the quality of a film or layer of the composition that is coated on a substrate. Such coating enhancers may function as plasticizers, surface leveling agents, and the like. Such coating enhancers are well-known to those skilled in the art, and are generally commercially available. Exemplary coating enhancers are: long chain alkanols such as oleyl alcohol, cetyl alcohol, and the like; glycols such as tripropylene glycol, tetraethylene glycol, and the like; and surfactants. While any suitable surfactant may be used as a coating enhancer, such surfactants are typically non-ionic. Exemplary non-ionic surfactants are those containing an alkyleneoxy linkage, such as ethyleneoxy, propyleneoxy, or a combination of ethyleneoxy and propyleneoxy linkages. It is preferred that one or more coating enhancers are used in the present compositions. The coating enhancers are typically used in the present compositions in an amount of 0 to 10% of total solids, preferably from 0.5 to 10% of total solids, and more preferably from 1 to 8% of total solids.
One or more stabilizers may optionally be added to the present compositions. Such stabilizers are useful for preventing unwanted hydrolysis or condensation of the silicon-containing moieties during storage. A variety of such stabilizers are known, and preferably the silicon-containing polymer stabilizer is an acid. Suitable acid stabilizers for the siloxane polymers include, without limitation, carboxylic acids, carboxylic acid anhydrides, mineral acids, and the like, and mixtures of any of the forgoing. Exemplary stabilizers include acetic acid, oxalic acid, malonic acid, malonic anhydride, malic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaric acid, glutaric anhydride, adipic acid, succinic acid, succinic anhydride, nitric acid and mixtures thereof. Carboxylic acids are preferred stabilizers, and more preferably the stabilizers are acetic acid, oxalic acid, malonic acid, malic acid, maleic acid, fumaric acid, citraconic acid, glutaric acid, adipic acid, succinic acid, and mixtures thereof. Such stabilizers are used in an amount of 0 to 20% of total solids, preferably from 0.1 to 15% of total solids, more preferably from 0.5 to 10% of total solids, and yet more preferably from 1 to 10% of total solids.
The compositions of the invention are prepared by combining the one or more present condensed polymers; one or more solvents; and any optional components, in any order. The compositions may be used as is, or may be further purified, such as by filtration.
The process of the present invention comprises (a) coating a substrate with the composition described above to form a coating layer; (b) curing the coating layer to form a polymeric underlayer; (c) disposing a layer of a photoresist on the polymeric underlayer; (d) pattern-wise exposing the photoresist layer to form a latent image; (e) developing the latent image to form a patterned photoresist layer having a relief image therein; (f) transferring the relief image to the substrate; and (g) removing the polymeric underlayer by wet stripping.
A coating layer comprising the present compositions may be coated on an electronic device substrate by any suitable means, such as spin-coating, slot-die coating, doctor blading, curtain coating, roller coating, spray coating, dip coating, and the like. Spin-coating is preferred. In a typical spin-coating method, the present compositions are applied to a substrate which is spinning at a rate of 500 to 4000 rpm for a period of 15 to 90 seconds to obtain a desired layer of the condensed polymer on the substrate. It will be appreciated by those skilled in the art that the thickness of the condensed polymer mixture layer may be adjusted by changing the spin speed, as well as the solids content of the composition.
A wide variety of electronic device substrates may be used in the present invention, such as: packaging substrates such as multichip modules; flat panel display substrates; integrated circuit substrates; substrates for light emitting diodes (LEDs) including organic light emitting diodes (OLEDs); semiconductor wafers; polycrystalline silicon substrates; and the like. Such substrates are typically composed of one or more of silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon germanium, gallium arsenide, aluminum, sapphire, tungsten, titanium, titanium-tungsten, nickel, copper, and gold. Suitable substrates may be in the form of wafers such as those used in the manufacture of integrated circuits, optical sensors, flat panel displays, integrated optical circuits, and LEDs. As used herein, the term “semiconductor wafer” is intended to encompass “an electronic device substrate,” “a semiconductor substrate,” “a semiconductor device,” and various packages for various levels of interconnection, including a single-chip wafer, multiple-chip wafer, packages for various levels, or other assemblies requiring solder connections. Such substrates may be any suitable size. Preferred wafer substrate diameters are 200 mm to 300 mm, although wafers having smaller and larger diameters may be suitably employed according to the present invention. As used herein, the term “semiconductor substrate” includes any substrate having one or more semiconductor layers or structures which may optionally include active or operable portions of semiconductor devices. A semiconductor device refers to a semiconductor substrate upon which at least one microelectronic device has been or is being batch fabricated.
After being coated on the substrate, the coating layer is optionally soft-baked at a relatively low temperature to remove any solvent and other relatively volatile components from the underlayer. Typically, the substrate is baked at a temperature of ≤200° C., preferably from 100 to 200° C., and more preferably from 100 to 150° C. The baking time is typically from 10 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, and more preferably from 60 to 90 seconds. When the substrate is a wafer, such baking step may be performed by heating the wafer on a hot plate. Such soft-baking step may be performed as part of the curing of the coating layer, or may be omitted altogether.
The coating layer comprising the present condensed polymers and crosslinkers is then cured to form an underlayer. The coating layer is sufficiently cured such that the film does not intermix with a subsequently applied organic layer, such as a photoresist or other organic layer disposed directly on the coating layer, while still maintaining the desired antireflective properties (n and k values) and etch selectivity of the underlayer film. The coating layer may be cured in an oxygen-containing atmosphere, such as air, or in an inert atmosphere, such as nitrogen and under conditions, such as heating, sufficient to provide a cured underlayer. This curing step is conducted preferably on a hot plate-style apparatus, although oven curing may be used to obtain equivalent results. Typically, such curing is performed by heating the condensed polymer layer at a curing temperature of ≤350° C., and preferably 200 to 250° C. Alternatively, a two-step curing process or a ramped temperature curing process may be used. Such two-step and ramped temperature curing conditions are well-known to those skilled in the art. The curing temperature selected should be sufficient for any thermal acid generator used to liberate acid to aid in curing of the condensed polymer film. The curing time may be from 10 seconds to 10 minutes, preferably from 30 seconds to 5 minutes, more preferably from 45 seconds to 5 minutes, and yet more preferably from 45 to 90 seconds. The choice of final curing temperature depends mainly upon the desired curing rate, with higher curing temperatures requiring shorter curing times. Following this curing step, the underlayer surface may optionally be passivated by treatment with a passivating agent such as a disilazane compound, such as hexamethyldisilazane, or by a dehydration bake step to remove any adsorbed water. Such passivating treatment with a disilazane compound is typically performed at 120° C.
After curing of the coating layer comprising the condensed polymer and crosslinker to form an underlayer, one or more processing layers, such as photoresists, hardmask layers, bottom antireflective coating (or BARC) layers, and the like, may be disposed on the underlayer. For example, a photoresist layer may be disposed, such as by spin coating, directly on the surface of the underlayer. Alternatively, a BARC layer may be coated directly on the underlayer, followed by curing of the BARC layer, and coating a photoresist layer directly on the cured BARC layer. In another alternative, an organic underlayer is first coated on a substrate and cured, a condensed polymer layer of the invention is then coated on the cured organic underlayer, the coating layer is then cured to form an underlayer, an optional BARC layer may be coated directly on the underlayer, followed by curing of the optional BARC layer, and coating a photoresist layer directly on the cured BARC layer. A wide variety of photoresists may be suitably used, such as those used in 193 nm lithography, such as those sold under the EPIC™ brand available from Dow Electronic Materials (Marlborough, Mass.). Suitable photoresists may be either positive tone development or negative tone development resists, or may be conventional negative resists. The photoresist layer is then imaged (exposed) using patterned actinic radiation, and the exposed photoresist layer is then developed using the appropriate developer to provide a patterned photoresist layer. An advantage of the present invention is that pattern collapse of the patterned photoresist layer upon contact with developer is reduced as compared to conventional wet-strippable silicon-containing underlayers. The pattern is next transferred from the photoresist layer to any optional BARC layer, and then to the underlayer by an appropriate etching technique, such as dry etching with an appropriate plasma. Typically, the photoresist is also removed during such etching step. Next, the pattern is transferred to any organic underlayer present using an appropriate technique, such as dry etching with O2 plasma, and then to the substrate as appropriate. Following these pattern transfer steps, the underlayer, and any optional organic underlayers are removed using conventional techniques. The electronic device substrate is then further processed according to conventional means.
The coating layers comprising the present condensed polymers and underlayers described herein are wet strippable. By “wet strippable” is meant that the coating layers and underlayers of the invention are removed, and preferably substantially removed (≥95% of film thickness), by contacting the coating layer or underlayer with conventional wet stripping compositions, such as: (1) an aqueous base composition, such as aqueous alkali (typically about 5%) or aqueous tetramethylammonium hydroxide (typically ≥5 wt %), (2) aqueous fluoride ion strippers such as ammonium fluoride/ammonium bifluoride mixtures, (3) a mixture of mineral acid, such as sulfuric acid or hydrochloric acid, and hydrogen peroxide, or (4) a mixture of ammonia, water and optionally hydrogen peroxide. A particular advantage of the present polymers, and particularly of the present underlayers, is that they are wet strippable upon contact with a mixture of ammonia and hydrogen peroxide. A suitable mixture of sulfuric acid and hydrogen peroxide is concentrated sulfuric acid+30% hydrogen peroxide. A wide range of ammonia and water mixtures may be used. A suitable mixture of ammonia, water and hydrogen peroxide is a mixture of ammonia+hydrogen peroxide+water in a weight ratio of 1:1:5 to 1:10:50, such as ratios of 1:1:10, 1:1:40, 1:5:40 or 1:1:50. Typically, such mixtures are used at temperatures of from room temperature to about 75° C. Preferably, ≥97%, and more preferably ≥99%, of the film thickness of the polymer layer or underlayer is removed by contacting the polymer layer or siloxane underlayer with either (i) mixture of sulfuric acid and hydrogen peroxide or (ii) a mixture of ammonium hydroxide and hydrogen peroxide.
Another advantage of the present polymer layers is that they are easily removed to allow re-work of the substrate, such as a wafer. In such a re-work process, a composition described above comprising one or more condensed polymers of the invention is coated on a substrate. The coated polymer layer is then optionally soft-baked, and then cured to form an underlayer. Next, a photoresist layer is coated on the underlayer, and the resist layer is imaged and developed. The patterned resist layer and the underlayer may then each be removed to allow the wafer to be re-worked. The underlayer is contacted with any of the above-described wet stripping compositions, such as aqueous tetramethylammonium hydroxide compositions (typically ≥5 wt %) and aqueous fluoride ion strippers such as ammonium fluoride/ammonium bifluoride mixtures, at a suitable temperature to remove the underlayer to provide the substrate free, or substantially free, of underlayer and readily undergo additional re-work as may be necessary. Such re-work includes coating another layer of the present condensed polymers on the substrate and processing the polymer coating as described above.
Example 1. A solution of tent-butyl methacrylate (tBMA), (173 g), gamma butyrolactone (GBLMA), (166 g) and 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), (60.6 g) dissolved in 1,3-dioxolane (304 g) and a solution of V-65 initiator (60.6 g) dissolved in 2:1 v/v tetrahydrofurane/acetonitrile (60.6 g) were both added dropwise over 2 hr. to 3-dioxolane (710 g) at 75° C. under a nitrogen blanket. After addition the reaction solution was held at 75° C. for an additional two hours, cooled to room temperature and precipitated into heptanes:MTBE (1:1 v/v, 14 L). The precipitated polymer was collected by vacuum filtration and vacuum oven dried for 24 hours to afford Polymer 1 (tBMA/GBLMA/TMSPMA 50/40/10) as a white solid (271 g, 68%). Mw was determined by GPC relative to polystyrene standard and was found to be 5700 Da.
Example 2. Polymers 2 to 12, reported in Table 2 below, were synthesized according to the procedure of Example 1 using the monomers listed in Table 1 below. The amount of each monomer used is reported in Table 2 in mol %. Polymers 2 to 12 were isolated in 20-99% yield and had the Mw reported in Table 2.
Example 3. The procedure of Example 2 is repeated and is expected to provide Polymers 13-18 reported in Table 3. The monomer numbers reported in Table 3 refer to the monomers in Table 1 of Example 2.
Example 4. A solution of hydrochloric acid (37 wt % in water, 7.76 g) in water (25.9 g) was added over 10 minutes to a mixture of TEOS (63.5 g, 50 mol %) and Polymer 1 from Example 1 (50.0 g, 50 mol %) in THF (270 g) and stirred at room temperature for 1 hr. The reaction mixture was heated to 63° C. for 20 hr. and then cooled to room temperature. PGEE (200 g) was added, the volatile species removed under reduced pressure, and the resulting solution was diluted with PGEE to provide Condensed Polymer 1 (10 wt % in PGEE, 600g) as a clear solution. Mw was determined by GPC relative to polystyrene standards (28,100 Da).
Example 5. Condensed Polymers 2 to 26, reported in Table 5 below, were synthesized according to the procedure of Example 4 using Polymers 1 to 12 from Examples 1 and 2 and the monomers listed in Table 4 below. The amount of each monomer used is reported in Table 5 in mol %. Condensed Polymers 2 to 12 were isolated in 20-99% yield and had the Mw reported in Table 5.
Example 6. The following components were combined: 1.6 wt % of Condensed Polymer 1; 0.09 wt % of a 0.1 wt % solution of tetrabutylammonium chloride in PGEE; 49 wt % of PGEE; 49.2 wt % of 2-hydroxyisobutyric acid methyl ester; 0.009 wt % acetic acid; and 0.2 wt % coating enhancer. The mixture was filtered through 0.2 gm polytetrafluoroethylene syringe to provide Comparative Formulation 1.
Example 7. The procedure of Example 6 was repeated to prepare Comparative Formulations 2 to 8 by replacing Condensed Polymer 1 with the Condensed Polymers reported in Table 6.
Example 8. The procedure of Example 6 was repeated except that Condensed Polymer 1 was replaced with a 85/15 w/w mixture of Condensed Polymer 1 and propoxylated pentaerythritol having on average 5 moles of propylene oxide (formula (11), a+b+c+d≈5) as a crosslinker to provide Formulation 1.
Example 9. The procedure of Example 6 was repeated to provide Formulations 2 to 15 by replacing Condensed Polymer 1 with the condensed polymer/crosslinker mixtures reported in Table 7. Crosslinker C1 is propoxylated pentaerythritol having on average 5 moles of propylene oxide of formula (11). Crosslinker C2 is a polymer of tert-butyl methacrylate/alpha-gammabutyrolactone methacrylate/hydroxyethyl methacrylate/methacrylic acid in a mole ratio of 25/25/25/25. Crosslinker C3 is a polymer of tert-butyl methacrylate/alpha-gammabutyrolactone methacrylate/hydroxyethyl methacrylate in a mole ratio of 50/25/25. Crosslinker C4 is polymer of methacrylic acid and hydroxyethyl methacrylate in a mole ratio of 60/40.
Example 10. Comparative Formulations from Examples 6 and 7 and Formulations of the invention from Examples 8 and 9 were spin-coated on a bare 200 mm silicon wafers at 1500 rpm and baked at 240° C. for 60 seconds using an ACT-8 Clean Track (Tokyo Electron Co.). The thickness of each coated film after baking of was measured with an OptiProbe™ instrument from Therma-wave Co. Each coated sample was then evaluated for SC-1 wet strippability using a 1/1/40 wt/wt/wt mixture of 30% NH4OH/30% H2O2/water. The SC-1 mixture was heated to 60° C., and coupons of each coated wafer were immersed into the solution for 1 min. The coupons were removed from the SC-1 mixture and rinsed with deionized water, and the film thickness was again measured. The film thickness loss for each sample was calculated as the difference in film thickness before and after contact with the stripping agent. A separate film prepared as described above was optionally tested for SC-1 strippability after etching. Etching was performed for 60 seconds using RIE790 from Plasma-Therm Co. with oxygen gas, 25 sscm flow, 180 W of power, and 6 mTorr of pressure. The stripping results, obtained as the rate of film removal in A/min, are reported in Table 8.
Comparative Formulations from Examples 6 and 7 and Formulations of the invention from Examples 8 and 9, at either 1.7% or 3.5% solids, were coated on 200 mm silicon wafers as described above with a target thickness of 400 Å or 1000 Å and measured (post cure) as described above. A puddle of commercially available 0.26N TMAH developer (MF CD-26) was applied to each wafer for 60 seconds, after which the wafers were rinsed with DI water, spin dried and the film thickness was re-measured. A final drying bake of 105° C./60 seconds was applied to each wafer and final film thickness was measured. The thickness loss of each film, reported as the rate of film removal in A/min, resulting from this TMAH strip is reported in Table 8. A negative film strip value indicates an increase in film thickness.
Claims
1. A composition comprising: (a) one or more solvents; (b) a condensate and/or hydrolyzate of (i) one or more condensed silicon-containing polymers comprising as polymerized units one or more first unsaturated monomers having a condensable silicon-containing moiety, wherein the condensable silicon-containing moiety is pendent to the polymer backbone, and (ii) one or more condensable silicon monomers; and (c) one or more crosslinkers free of Si—O linkages
2. The composition of claim 1 wherein at least one condensable silicon monomer has the formula (8)
- Si(R50)p(X)4-p (8)
- wherein p is an integer from 0 to 3; each R50 is independently chosen from a C1-30 hydrocarbyl moiety and a substituted C1-30 hydrocarbyl moiety; and each X is independently chosen from halogen, C1-10 alkoxy, —OH, —O—C(O)—R50, and —(O—Si(R51)2)p2—X1; X1 is independently chosen from halogen, C1-10 alkoxy, —OH, —O—C(O)—R50; each R51 is independently chosen from R50 and X; and p2 is an integer from 1 to 10.
3. The composition of claim 2 wherein p=0 or 1.
4. The composition of claim 1 wherein the condensable silicon-containing moiety has the formula
- *-L-SiR1bY13-b
- wherein L is a single bond or a divalent linking group; each R1 is independently chosen from H, C1-10-alkyl, C2-20-alkenyl, C5-20-aryl, and C6-20-aralkyl; each Y1 is independently chosen from halogen, C1-10-alkoxy, C5-10-aryloxy, C1-10-carboxy; b is an integer from 0 to 2; and * denotes the point of attachment to the polymer backbone.
5. The composition of claim 4 wherein L is a divalent linking group.
6. The composition of claim 5 wherein the divalent linking group is an organic radical having from 1 to 20 carbon atoms and optionally one or more heteroatoms.
7. The composition of claim 4 wherein the divalent linking group has the formula —C(═O)—O-L1- wherein L1 is a single bond or an organic radical having from 1 to 20 carbon atoms.
8. The composition of claim 1 wherein at least one first unsaturated monomer has the formula (1)
- wherein L is a single bond or a divalent linking group; each Rl is independently chosen from H, C1-10-alkyl, C2-20-alkenyl, C5-20-aryl, and C6-20-aralkyl; each of R2 and R3 are independently chosen from H, C1-4 alkyl, C1-4 haloalkyl, halogen, C5-20-aryl, C6-20 aralkyl, and CN; R4 is chosen from H, C1-10 alkyl, C1-10 haloalkyl, halogen, C5-20-aryl, C6-20 aralkyl, and C(═O)R5; R5 is chosen from OR6 and N(R7)2; R6 is chosen from H, and C1-20 alkyl; each R7 is independently chosen from H, C1-20 alkyl, and C6-20 aryl; each Y1 is independently chosen from halogen, C1-10-alkoxy, C5-10-aryloxy, C1-10-carboxy; and b is an integer from 0 to 2.
9. The composition of claim 1 wherein the condensate and/or hydrolyzate further comprises as polymerized units one or more second unsaturated monomers free of a condensable silicon-containing moiety.
10. The composition of claim 9 wherein at least one second unsaturated monomer has an acidic proton and having a pKa in water from −5 to 13.
11. The composition of claim 9 wherein at least one second unsaturated monomer has the formula (2)
- wherein Z is chosen from an acid decomposable group, a C4-30 organic residue bound to the oxygen through a tertiary carbon, a C4-30 organic residue comprising an acetal functional group, and a monovalent organic residue having a lactone moiety; and R10 is independently chosen from H, C1-4 alkyl, C1-4 haloalkyl, halogen, and CN.
12. The composition of claim 1 wherein the condensate and/or hydrolyzate further comprises as polymerized units one or more unsaturated monomers having a chromophore moiety.
13. The composition of claim 12 wherein the chromophore moiety is pendent from the polymer backbone.
14. A method comprising (a) coating a substrate with the composition of claim 1 to form a coating layer; (b) curing the coating layer to form a polymeric underlayer; (c) disposing a layer of a photoresist on the polymeric underlayer; (d) pattern-wise exposing the photoresist layer to form a latent image; (e) developing the latent image to form a patterned photoresist layer having a relief image therein; (f) transferring the relief image to the substrate; and (g) removing the polymeric underlayer by wet stripping.
15. The method of claim 14 wherein the polymeric underlayer is removed by wet stripping.
Type: Application
Filed: Sep 18, 2018
Publication Date: May 16, 2019
Inventors: Charlotte A Cutler (Hopkinton, MA), Li Cui (Westborough, MA), Shintaro Yamada (Shrewsbury, MA), Paul J. LaBeaume (Auburn, MA), Suzanne M. Coley (Mansfield, MA), James F. Cameron (Brookline, MA), Daniel Greene (Shrewsbury, MA)
Application Number: 16/133,739
