METHODS OF FORMING MASKING LAYERS FOR USE IN FORMING INTEGRATED CIRCUIT PRODUCTS
One illustrative method disclosed herein includes forming a seed layer above a structure, forming a nucleation layer on the seed layer, forming a plurality of spaced-apart, vertically oriented alloy structures that are comprised of materials from the seed layer and the nucleation layer, forming a sacrificial material layer above the nucleation layer and around the alloy structures, performing an etching process to remove the alloy structures and portions of the seed layer so as to thereby define a plurality of openings, forming an initial masking structure in each of the openings, performing an etching process to remove the sacrificial material layer and the nucleation layer so as to thereby expose the structure and define a masking layer comprised of the initial masking structures, and performing at least one process operation on the structure through the masking layer.
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1. Field of the Invention
Generally, the present disclosure relates to the manufacture of sophisticated semiconductor devices, and, more specifically, to various methods of forming masking layers for use in forming integrated circuit products.
2. Description of the Related Art
The fabrication of advanced integrated circuits, such as CPUs, storage devices, ASICs (application specific integrated circuits) and the like, requires a large number of circuit elements, such as transistors, capacitors, resistors, etc., to be formed on a given chip area according to a specified circuit layout. During the fabrication of complex integrated circuits using, for instance, MOS (Metal-Oxide-Semiconductor) technology, millions of transistors, e.g., N-channel transistors (NFETs) and/or P-channel transistors (PFETs), are formed on a substrate including a crystalline semiconductor layer. A field effect transistor, irrespective of whether an NFET transistor or a PFET transistor is considered, typically includes doped source and drain regions that are formed in a semiconducting substrate and separated by a channel region. A gate insulation layer is positioned above the channel region and a conductive gate electrode is positioned above the gate insulation layer. By applying an appropriate voltage to the gate electrode, the channel region becomes conductive and current is allowed to flow from the source region to the drain region.
Fabricating such circuit elements involves forming various “features” or “structures” of the devices, such as gate electrode structures, metal lines, conductive contacts, etc. Each of these features has a so-called “critical dimension,” which is typically the smallest size of a particular feature, e.g., the width of a line. As another example, for transistor devices, the critical dimension is gate length, which approximately corresponds to the width of the gate electrode that is positioned above the channel region of the device. Historically, such features and structures are typically formed by depositing a layer of material, forming a patterned photoresist mask layer above the layer of material and thereafter performing an etching process on the layer of material through the patterned photoresist mask layer, wherein the remaining portion of the layer of material after the etching process is the desired feature or structure. In other cases, a trench may be formed in a layer of material by performing an etching process through a patterned photoresist mask layer and thereafter a desired feature, e.g., a metal line, may be formed in the trench. The deposition, masking and etching techniques are performed using a variety of known deposition, etching and photolithography tools and techniques.
As should be clear from the foregoing, photolithography is one of the basic processes used in manufacturing integrated circuit products. At a very high level, photolithography involves (1) forming a layer of light or radiation-sensitive material, such as photoresist, above a layer of material or a substrate, (2) selectively exposing the radiation-sensitive material to a light generated by a light source (such as a DUV or EUV source) to transfer a pattern defined by a mask or reticle (interchangeable terms) to the radiation-sensitive material, and (3) developing the exposed layer of radiation-sensitive material to define a patterned mask layer. In general, the illuminated regions of the layer of photoresist material are chemically activated. In the case of a so-called “positive” resist mask, the exposed regions of the layer of photoresist material are subsequently removed in the developing process. In the case of a so-called “negative” resist mask, the illuminated regions of the layer of photoresist material are not removed during the developing process. Various process operations, such as etching or ion implantation processes, may then be performed on the underlying layer of material or substrate through the patterned photoresist mask layer.
Over the recent years and continuing to present day, there has been a constant demand for electrical consumer devices with improved operating characteristics, such as operating speed, and for physically smaller devices. As a result, device designers have reduced the physical size of the various features that are used in manufacturing integrated circuit devices to increase their performance capability and to produce smaller devices with more functionality, e.g., cell phones. To be more specific, the gate length of current generation transistor devices has been reduced to about 25-30 nm, and further reductions are contemplated in the future. Of course, the ultimate goal in integrated circuit fabrication is to faithfully reproduce the original circuit design on the integrated circuit product. Historically, the feature sizes and pitches (spacing between features) employed in integrated circuit products were such that a desired pattern could be formed using a single patterned photoresist masking layer. However, in recent years, device dimensions and pitches have been reduced to the point where existing photolithography tools, e.g., 193 nm wavelength photolithography tools, cannot form single patterned mask layers with all of the features of the overall target pattern.
To overcome the limitations of current-day photolithography tools and techniques, the semiconductor manufacturing industry has developed and employed several so-called double patterning techniques to be able to manufacture devices with features sizes that are smaller than can be patterned using a single exposure photolithography process. Double patterning generally involves the formation and use of two separate patterned photoresist mask layers instead of one to form the desired feature. Using these techniques, the second mask must be accurately aligned with the first mask. Two examples of known double patterning techniques include a so-called LELE (Litho-Etch-Litho-Etch) process and an LFLE (Litho-Freeze-Litho-Etch) process. However, such double patterning techniques are expensive and add to processing complexity.
The present disclosure is directed to various methods of forming masking layers for use in forming integrated circuit products that may solve or at least reduce some of the problems identified above.
SUMMARY OF THE INVENTIONThe following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.
Generally, the present disclosure is directed to various methods of forming masking layers for use in forming integrated circuit products. One illustrative method disclosed herein includes forming a seed layer above a structure, e.g., a layer of material, wherein the seed layer is comprised of a metal-containing material, forming a nucleation layer on the seed layer, wherein the nucleation layer is comprised of a transition metal oxide ceramic material, performing at least one thermal treatment process at a temperature so as to generate a plurality of spaced-apart, vertically oriented alloy structures, wherein the alloy structures are comprised of at least one material from the seed layer and at least one material from the nucleation layer and, after forming the alloy structures, forming a sacrificial material layer above the nucleation layer and around the alloy structures. In this example, the method also includes the steps of performing at least one etching process to remove the alloy structures and portions of the seed layer so as to thereby define a plurality of openings, forming an initial masking structure in each of the openings, performing at least one etching process to remove the sacrificial material layer and the nucleation layer so as to thereby expose the structure and the initial masking structures, forming additional masking material selectively on the initial masking structures so as to thereby define a plurality of final masking structures, wherein the final masking structures define a masking layer, and performing at least one process operation on the structure through the masking layer.
Another illustrative method disclosed herein includes forming a seed layer above a structure, wherein the seed layer is comprised of a metal-containing material, forming a nucleation layer on the seed layer, wherein the nucleation layer is comprised of a transition metal oxide ceramic material, performing at least one thermal treatment process at a temperature so as to generate a plurality of spaced-apart, vertically oriented alloy structures, wherein the alloy structures are comprised of at least one material from the seed layer and at least one material from the nucleation layer and, after forming the alloy structures, forming a sacrificial material layer above the nucleation layer and around the alloy structures. In this example, the method further includes the steps of performing at least one etching process to remove the sacrificial material layer and the nucleation layer and to pattern the seed layer so as to thereby expose the alloy structures and portions of the structure, forming a spacer structure around each of the exposed alloy structures, forming a layer of masking material around the spacer structures, performing at least one etching process to remove the spacer structure, the alloy structure and the patterned seed layer so as to thereby define a masking layer comprised of a plurality of openings, and performing at least one process operation on the structure through the masking layer.
The disclosure may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:
While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTIONVarious illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.
The present disclosure is directed to various methods of forming masking layers, both positive and negative masking layers, for use in forming integrated circuit products. The masking layers disclosed herein may be employed for any purpose in the manufacture of integrated circuit products, e.g., the formation of a patterned hard mask, as used in etching or ion implantation processes, etc. Moreover, as will be readily apparent to those skilled in the art upon a complete reading of the present application, the methods disclosed herein may be used in manufacturing integrated circuit products that are fabricated using any of a variety of different technologies, e.g., NFET, PFET, CMOS, etc., and they may be employed in manufacturing a variety of different integrated circuit products, including, but not limited to, ASIC's, logic devices, memory devices, etc. With reference to the attached drawings, various illustrative embodiments of the methods disclosed herein will now be described in more detail.
As mentioned above, by controlling various parameters of the thermal treatment processes, such as thermal budget, ramp rate, temperature and/or duration, the pitch or pattern of the alloy structures 18 may be controlled. For example, the ramp rate used in the first thermal treatment process may range from 10-80° C./sec. In general, the greater the ramp rate, the more closely spaced will be the alloy structures 18, i.e., the greater the ramp rate, the greater the density of the alloy structures. Additionally, the higher the temperature of the thermal treatment process, the more SBT material is transformed from amorphous to crystalline material (closes the matrix). The longer the duration of the first thermal treatment process, the more SBT material is crystallized. The thickness of the layer 16 also influences the nucleation within a certain range of thickness: the thicker the layer 16, the more grain nuclei are formed and hence the denser is the matrix. However, at some point above a certain thickness (e.g., about 100 nm), this effect goes into a saturation. Additionally, above a certain temperature/time combination (thermal budget) of the thermal treatment process, the crystalline matrix is closed and grains could grow together. The thermal budget of the thermal treatment process could also influence the diameter of the resulting alloy structures 18. In general, the greater the thermal budget for the second forming gas anneal process, the taller and larger (diameter) will be the resulting alloy structures 18.
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In FIG. 2Hm one or more etching processes have been performed through the positive masking layer 10P (depicted in
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The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the process steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.
Claims
1. A method, comprising:
- forming a seed layer above a structure, said seed layer being comprised of a metal-containing material;
- forming a nucleation layer on said seed layer, said nucleation layer comprising a transition metal oxide ceramic material;
- performing at least one thermal treatment process at a temperature so as to generate a plurality of spaced-apart, vertically oriented alloy structures, wherein said alloy structures are comprised of at least one material from said seed layer and at least one material from said nucleation layers;
- after forming said alloy structures, forming a sacrificial material layer above said nucleation layer and around said alloy structures;
- performing at least one etching process to remove said alloy structures and portions of said seed layer so as to thereby define a plurality of openings;
- forming an initial masking structure in each of said openings;
- performing at least one etching process to remove said sacrificial material layer and said nucleation layer so as to thereby expose said structure and define a masking layer comprised of at least said initial masking structures; and
- performing at least one process operation on said structure through said masking layer.
2. The method of claim 1, wherein said seed layer is comprised of one of the following materials: platinum, copper or aluminum.
3. The method of claim 1, wherein said nucleation layer is comprised of a strontium, bismuth, tantalum, or niobium containing material.
4. The method of claim 1, wherein performing said at least one thermal treatment process comprises performing a first thermal treatment process at a temperature that falls within the range of about 600-850° C. in an oxygen-containing ambient.
5. The method of claim 4, wherein a temperature ramp rate during said first thermal treatment process falls within a range of about 10-80° C./sec.
6. The method of claim 4, further comprising performing a second thermal treatment process at a temperature that falls within the range of about 230-430° C. in a hydrogen-containing ambient.
7. The method of claim 1, wherein performing said at least one process operation comprises performing at least one etching process.
8. The method of claim 1, wherein said sacrificial material layer is comprised of silicon dioxide, silicon nitride or polysilicon.
9. The method of claim 1, wherein said structure is a layer of material.
10. A method, comprising:
- forming a seed layer above a structure, said seed layer being comprised of a metal-containing material;
- forming a nucleation layer on said seed layer, said nucleation layer comprising a transition metal oxide ceramic material;
- performing at least one thermal treatment process at a temperature so as to generate a plurality of spaced-apart, vertically oriented alloy structures, wherein said alloy structures are comprised of at least one material from said seed layer and at least one material from said nucleation layer;
- after forming said alloy structures, forming a sacrificial material layer above said nucleation layer and around said alloy structures;
- performing at least one etching process to remove said alloy structures and portions of said seed layer so as to thereby define a plurality of openings;
- forming an initial masking structure in each of said openings;
- performing at least one etching process to remove said sacrificial material layer and said nucleation layer so as to thereby expose said structure and said initial masking structures;
- forming additional masking material selectively on said initial masking structures so as to thereby define a plurality of final masking structures, wherein said final masking structures define a masking layer; and
- performing at least one process operation on said structure through said masking layer.
11. The method of claim 10, wherein said seed layer is comprised of one of the following materials: platinum, copper or aluminum.
12. The method of claim 10, wherein said nucleation layer is comprised of a strontium, bismuth, tantalum, or niobium containing material.
13. The method of claim 10, wherein performing said at least one thermal treatment process comprises performing a first thermal treatment process at a temperature that falls within the range of about 600-850° C. in an oxygen-containing ambient.
14. The method of claim 13, wherein a temperature ramp rate during said thermal treatment process falls within a range of about 10-80° C./sec.
15. The method of claim 13, further comprising performing a second thermal treatment process at a temperature that falls within the range of about 230-430° C. in a hydrogen-containing ambient.
16. A method, comprising:
- forming a seed layer above a structure, said seed layer being comprised of one of the following materials: platinum, copper or aluminum;
- forming a nucleation layer on said seed layer, said nucleation layer being comprised of a strontium, bismuth, tantalum, or niobium containing material;
- performing a first thermal treatment process at a temperature so as to generate a plurality of spaced-apart, vertically oriented alloy structures, wherein said alloy structures are comprised of at least one material from said seed layer and at least one material from said nucleation layer and wherein said first thermal treatment process is performed at a temperature that falls within the range of about 600-850° C.;
- after forming said alloy structures, forming a sacrificial material layer above said nucleation layer and around said alloy structures;
- performing at least one etching process to remove said alloy structures and portions of said seed layer so as to thereby define a plurality of openings;
- forming an initial masking structure in each of said openings;
- performing at least one etching process to remove said sacrificial material layer and said nucleation layer so as to thereby expose said structure and said initial masking structures;
- forming additional masking material selectively on said initial masking structures so as to thereby define a plurality of final masking structures, wherein said final masking structures define a masking layer; and
- performing at least one process operation on said structure through said masking layer.
17. The method of claim 16, wherein a temperature ramp rate during at least a portion of said thermal treatment process falls within a range of about 10-80° C./sec.
18. The method of claim 16, further comprising performing a second thermal treatment process at a temperature that falls within the range of about 230-430° C. in a hydrogen-containing ambient prior to forming said sacrificial material layer.
19. A method, comprising:
- forming a seed layer above a structure, said seed layer being comprised of a metal-containing material;
- forming a nucleation layer on said seed layer, said nucleation layer comprising a transition metal oxide ceramic material;
- performing a first thermal treatment process at a temperature so as to generate a plurality of spaced-apart, vertically oriented alloy structures, wherein said alloy structures are comprised of at least one material from said seed layer and at least one material from said nucleation layer;
- after forming said alloy structures, forming a sacrificial material layer above said nucleation layer and around said alloy structures;
- performing at least one etching process to remove said sacrificial material layer and said nucleation layer and to pattern said seed layer so as to thereby expose said alloy structures and portions of said structure;
- forming a spacer structure around each of said exposed alloy structures;
- forming a layer of masking material around said spacer structures;
- performing at least one etching process to remove said spacer structures, said alloy structure and said patterned seed layer so as to thereby define a masking layer comprised of a plurality of openings; and
- performing at least one process operation on said structure through said masking layer.
20. The method of claim 19, wherein said seed layer is comprised of one of the following materials: platinum, copper or aluminum.
21. The method of claim 19, wherein said nucleation layer is comprised of a strontium, bismuth, tantalum, or niobium containing material.
22. The method of claim 19, wherein said first thermal treatment process is performed at a temperature that falls within the range of about 600-850° C. in an oxygen-containing ambient prior to forming said sacrificial material layer.
23. The method of claim 22, wherein a temperature ramp rate during at least a portion of said first thermal treatment process falls within a range of about 10-80° C./sec.
24. The method of claim 22, further comprising performing a second thermal treatment process at a temperature that falls within the range of about 230-430° C. in a hydrogen-containing ambient.
25. A method, comprising:
- forming a seed layer above a structure, said seed layer being comprised of one of the following materials: platinum, copper or aluminum;
- forming a nucleation layer on said seed layer, said nucleation layer being comprised of a strontium, bismuth, tantalum, or niobium containing material;
- performing a first thermal treatment process at a temperature so as to generate a plurality of spaced-apart, vertically oriented alloy structures, wherein said alloy structures are comprised of at least one material from said seed layer and at least one material from said nucleation layer and wherein said first thermal treatment process is performed at a temperature that falls within the range of about 600-850° C.;
- after forming said alloy structures, forming a sacrificial material layer above said nucleation layer and around said alloy structures;
- performing at least one etching process to remove said sacrificial material layer and said nucleation layer and to pattern said seed layer so as to thereby expose said alloy structures and portions of said structure;
- forming a spacer structure around each of said exposed alloy structures;
- forming a layer of masking material around said spacer structures;
- performing at least one etching process to remove said spacer structures, said alloy structures and said patterned seed layer so as to thereby define a masking layer comprised of a plurality of openings; and
- performing at least one process operation on said structure through said masking layer.
26. The method of claim 25, wherein a temperature ramp rate during at least a portion of said first thermal treatment process falls within a range of about 10-80° C./sec.
27. The method of claim 25, further comprising performing a second thermal treatment process at a temperature that falls within the range of about 230-430° C. in a hydrogen-containing ambient prior to forming said sacrificial material layer.
Type: Application
Filed: Mar 28, 2013
Publication Date: Oct 2, 2014
Applicant: GLOBALFOUNDRIES Inc. (Grand Cayman)
Inventor: Manfred Heinrich Moert (Dresden)
Application Number: 13/852,043
International Classification: H01L 21/768 (20060101);