Abstract: A process is disclosed for forming multilayered polyimide structure from negative photosensitive polyimide precursors. An initial polyimide layer is deposited and imagewise exposed. The unexposed portions of the initial polyimide layer are inhibited and then a second polyimide layer is deposited and likewise imagewise exposed. The films are developed, thereby forming a multilayer polyimide structure. After formation of the multilayer polyimide structure, a conductive material is applied on a substrate and then the polyimide layers are lifted off thereby forming a desired pattern of metallization.

Abstract: Thermostable compounds are prepared by mixing perylene dianhydride with one or more aminosilanes in a molar ratio of 1:4 in an inert solvent, and the aminosilanes may comprise aminoalkylakoxysilanes. Upon heating the mixture a thermostable coating is formed. Prior to heating the mixture may be spin-applied to a substrate. The coating may be used in semiconductor device fabrication as the mixture has good spin-on characteristics with the cured compound being thermally stable over 600.degree. C. and having good etch characteristics.

Abstract: A process is disclosed for making circuit elements by photolithography comprising depositing an antireflective polyimide or polyimide precursor layer on a substrate and heating the substrate at 200.degree. C. to 500.degree. C. to provide a functional integrated circuit element that includes an antireflective polyimide layer. The antireflective polyimide layer contains a sufficient concentration of at least one chromophore to give rise to an absorbance sufficient to attenuate actinic radiation at 405 or 436 nm. Preferred chromophores include those arising from perylenes, naphthalenes and anthraquinones. The chromophore may reside in a dye which is a component of the polyimide coating mixture or it may reside in a residue which is incorporated into the polyimide itself.

Abstract: Methods and compositions for the selective etching of silicon in the presence of p-doped silicon are disclosed whereby a portion of a silicon surface may be dissolved while a p-doped pattern in the surface remains substantially undissolved. The compositions comprise (a) an aqueous solution of an alkali metal hydroxide or a tetraalkylammonium hydroxide; and (b) a high flash point alcohol, phenol, polymeric alcohol, or polymeric phenol.

Abstract: A process is disclosed for making circuit elements by photolithography comprising depositing an antireflective polyimide or polyimide precursor layer on a substrate and heating the substrate at 200.degree. C. to 500.degree. to provide a functional integrated circuit element that includes an antireflective polyimide layer. The antireflective polyimide layer contains a sufficient concentration of at least one chromophore to give rise to an absorbance sufficient to attenuate actinic radiation at 405 or 436 nm. Preferred chromophores include those arising from perylenes, naphthalenes and anthraquinones. The chromophore may reside in a dye which is a component of the polyimide coating mixture or it may reside in a residue which is incorporated into the polyimide itself.

Abstract: Disclosed is a process for passivating a metal surface in a metal/polyimide structure, such as a polyimide layer on a semiconductor substrate containing a pattern of metallization. The process involves the formation of an intermediate layer of a silsesquioxane polymer between the polyimide layer and the substrate. The silsesquioxane layer passivates the metal, to inhibit interaction between the metal surface and the polyimide precursor material used in forming the polyimide, to provide a moisture-resistant and oxidation-resistant interface.

Abstract: Solutions of polyamide alkyl esters are stabilized by incorporation of a select acidic compound, which inhibits premature imidization of the ester.

Abstract: Disclosed is a process for passivating a metal surface in a metal/polyimide structure, such as a polyimide layer on a semiconductor substrate containing a pattern of metallization. The process invovles the formation of an intermediate layer of a silsesquioxane polymer between the polyimide layer and the substrate. The silsesquioxane layer passivates the metal, to inhibit interaction between the metal surface and the polyimide precursor material used in forming the polyimide, to provide a moisture-resistant and oxidation-resistant interface.

Abstract: In order to improve the adhesion of a polyimide layer to an underlying metal surface, an organic solution which cures to a silsesquioxane copolymer is applied to the surface. The polyimide and the copolymer are formed during a simultaneous curing step.

Abstract: An improved insulating layer is formed by applying to a suitable substrate an organic solution, prepared by reacting an aminoalkoxysilane monomer, an arylalkoxysilane or arylsilazane monomer and water in a solvent, and then heating the coated substrate under conditions so as to evaporate the solvent and form a layer of cured ladder-type silsesquioxane copolymer. The insulating layer, which demonstrates excellent planarizing and thermal stability characteristics, is particularly useful in semiconductor device applications.

Abstract: A process for forming a pattern on a substrate utilizing photolithographic techniques. In this process a layer of polymeric material containing a fluorine-containing compound is applied over the substrate and cured. A layer of photoresist material is applied over the polymeric material imagewise exposed and developed to reveal the image on the underlying polymeric material. Thereafter, the photoresist is silylated, and the structure is reactive ion etched to transfer the pattern to the underlying substrate. The fluorine component provides an underlying structure free of residue and cracking.

Abstract: The present invention provides a novel approach to forming a RIE etch barrier in processes where thermally stable polymeric materials containing free carboxyl groups, such as polyamic acid polymers, are present as masking layers in the electrical device to be fabricated. The present process takes advantage of the discovery that polyamic acids complex with certain metallic cations under slightly acidic conditions to form polyamic acid salts. These salts can be made to further react with a variety of etching gases to form a non-volatile salt or oxide which imparts etch barrier properties to that portion of the polyamic acid layer exposed to the metallic cations.

Abstract: An improved method for anisotropically etching the (100) crystallographic plane of silicon wafers, involves immersing the wafers in an etching solution containing an aromatic compound having at least two adjacent hydroxyl groups and a polar functional group on the ring, an amine and water. A quality etch at an appreciably greater rate is achieved.

Abstract: The cleaning compositions of the present invention comprise pyridine or substituted pyridines alone or in admixture with sulfoxides. Preferred compositions comprise pyridine and dimethylsulfoxide (DMSO). Any concentration of DMSO from 0-50% can be used, but preferred compositions contain 5-25% DMSO. The present invention is employed to treat integrated circuit modules enclosed in a cap or can. Following treatment the cap or can, which is sealed to the substrate by means of the cured epoxy, can be removed to allow rework. The preferred method of removing the cured epoxy from module substrates is by refluxing in the solution. The cured epoxy is totally removed and there is no attack of the Al-Cu or Sn-Pb metallurgies or chip polyimide passivation. The silicone overcoat material is not removed from behind the chips, eliminating the need to reapply the material after rework.

Abstract: A polyamic acid copolymer forming a polyimide comprising, in mole percent, from greater than 5 percent to about 45 percent pyromellitic dianhydride, from about 5 percent to about 45 percent oxydiphthalic dianhydride, and about 50 percent of oxydianiline. Polyimides formed by curing the copolymer are also disclosed as is a process for forming a heat sealable coating on or dielectric isolation layer within electronic circuitry using the copolymer.

Abstract: A method of forming an etch barrier in the reactive ion etching of an aromatic polyamic acid/imide which comprises:coating a surface with a layer of an aromatic polyamic acid;at least partially curing the layer of aromatic polyamic acid to the corresponding aromatic polyimide;in situ converting the surface layer of the aromatic polyimide to a silicon containing alkyl polyamide/imide;applying, exposing, and developing a layer of photoresist over the silicon containing alkyl polyamide/imide to selectively expose a portion of the silicon containing alkyl polyamide/imide surface layer;reactive ion etching the exposed portion of the surface layer of the silicon containing alkyl polyamide/imide with carbon tetrafluoride to remove the exposed portion of the silicon containing alkyl polyamide/imide surface layer;reactive ion etching the resultant structure with an oxygen agent to etch an interconnect in the aromatic polyimide while removing the photoresist down to the silicon containing alkyl polyamide/imide surface