Source: http://www.google.com/patents/US7261997?dq=mezick
Timestamp: 2017-09-21 02:54:40
Document Index: 144345059

Matched Legal Cases: ['art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 2', 'art 2', 'art 2', 'art 2']

Patent US7261997 - Spin bowl compatible polyamic acids/imides as wet developable polymer ... - Google Patents
Anti-reflective compositions and methods of using these compositions to form circuits are provided. The compositions comprise a polymer dissolved or dispersed in a solvent system. In a preferred embodiment the polymers of the composition include recurring monomers having the formulas where: (1) each...http://www.google.com/patents/US7261997?utm_source=gb-gplus-sharePatent US7261997 - Spin bowl compatible polyamic acids/imides as wet developable polymer binders for anti-reflective coatings
Publication number US7261997 B2
Application number US 10/180,624
Also published as EP1540420A2, EP1540420A4, EP1540420B1, US7608380, US20030166828, US20040210034, US20060063106, US20100040988, WO2004000928A2, WO2004000928A3
Publication number 10180624, 180624, US 7261997 B2, US 7261997B2, US-B2-7261997, US7261997 B2, US7261997B2
Inventors Robert Christian Cox, Charles J. Neef
Original Assignee Brewer Science Inc.
Patent Citations (19), Non-Patent Citations (3), Referenced by (8), Classifications (35), Legal Events (4)
US 7261997 B2
Anti-reflective compositions and methods of using these compositions to form circuits are provided. The compositions comprise a polymer dissolved or dispersed in a solvent system. In a preferred embodiment the polymers of the composition include recurring monomers having the formulas
where: (1) each R is individually selected from the group consisting of hydrogen, —OH, aliphatics, and phenyls; and (2) L is selected from the group consisting of —SO2— and —CR′2—, where each R′ is individually selected from the group consisting of hydrogen, aliphatics, phenyls, and —CX3, where each X is individually selected from the group consisting of the halogens. The resulting compositions are spin bowl compatible (i.e., they do not crosslink prior to the bake stages of the microlithographic processes or during storage at room temperature), are wet developable, and have superior optical properties.
1. In a composition for use in photolithographic processes wherein the composition comprises a polymer dissolved or dispersed in a solvent system, the improvement being that said composition comprises a crosslinking agent and said polymer comprises recurring monomers having the formulas
each R is individually selected from the group consisting of hydrogen, —OH, aliphatics, and phenyls; and
L is selected from the group consisting of —SO2— and —CR′2—, where each R′ is individually selected from the group consisting of hydrogen, aliphatics, phenyls, and —CX3, where each X is individually selected from the group consisting of the halogens.
2. The polymer of claim 1, wherein at least one R on each ring is —OH.
3. The polymer of claim 1, wherein L is —SO2—.
4. The polymer of claim 1, wherein L is —CR′2—.
5. The combination of:
an anti-reflective layer adjacent said surface, said anti-reflective layer being formed from a composition comprising a polymer dissolved or dispersed in a solvent system, said polymer comprising recurring monomers having the formulas
6. The combination of claim 5, said layer being a cured layer.
7. The combination of claim 6, said cured layer being wet developable.
8. The combination of claim 6, wherein said cured layer has a percent solubility of at least about 50% when propylene glycol methyl ether acetate is the solvent.
9. The combination of claim 5, wherein said substrate is selected from the group consisting of silicon wafers and ion implant layers.
10. The combination of claim 6, said combination further comprising a photoresist layer adjacent said cured layer.
11. The combination of claim 6, said cured layer being at least about 90% soluble in a base developer.
12. The combination of claim 5, wherein at least one R on each ring is —OH.
13. The combination of claim 5, wherein L is —SO2—.
14. The combination of claim 5, wherein L is —CR′2—.
15. The combination of claim 14, where each R′ is —CF3.
16. A method of using a composition in photolithographic processes, said method comprising the step of applying a quantity of a composition to a substrate to form a layer thereon, said composition comprising a polymer dissolved or dispersed in a solvent system, said composition comprising a crosslinking agent, said polymer comprising recurring monomers having the formulas
L is selected from the group consisting of SO2and —CR′2—, where each R′ is individually selected from the group consisting of hydrogen, aliphatics, phenyls, and —CX3, where each X is individually selected from the group consisting of the halogens.
17. The method of claim 16, wherein said applying step comprises spin-coating said composition onto said substrate surface.
18. The method of claim 16, wherein said substrate has a hole formed therein, said hole being defined by a bottom wall and sidewalls, and said applying step comprises applying said composition to at least a portion of said bottom wall and sidewalls.
19. The method of claim 16, further including the step of baking said layer, after said applying step, at a temperature of from about 100-250° C. to yield a cured layer.
20. The method of claim 19, further including the step of applying a photoresist to said cured layer.
21. The method of claim 20, furthering including the steps of:
exposing at least a portion of said photoresist to activating radiation; and
developing said exposed photoresist.
22. The method of claim 21, wherein said developing step results in the removal of said cured layer from areas adjacent said exposed photoresist.
23. The method of claim 16, wherein said substrate comprises an ion implant layer.
This application claims the priority benefit of a provisional application entitled SPIN BOWL COMPATIBLE POLYAMIC ACIDS/IMIDES AS WET DEVELOPABLE POLYMER BINDERS FOR BARCS, Ser. No. 60/349,569, filed Jan. 17, 2002, incorporated by reference herein.
The present invention is concerned with new polymers and anti-reflective compositions for use in the manufacture of microelectronic devices. These compositions include a polyamic acid and are developable in aqueous photoresist developers.
However, a frequent problem encountered by photoresists during the manufacture of semiconductor devices is that activating radiation is reflected back into the photoresist by the substrate on which it is supported. Such reflectivity tends to cause blurred patterns which degrade the resolution of the photoresist. Degradation of the image in the processed photoresist is particularly problematic when the substrate is non-planar and/or highly reflective. One approach to address this problem is the use of an anti-reflective coating applied to the substrate beneath the photoresist layer. While anti-reflective coatings are effective at preventing or minimizing reflection, their use requires an additional break-through step in the process in order to remove the coatings. This necessarily results in an increased process cost.
One solution to this problem has been the use of wet developable anti-reflective coatings. These types of coating can be removed along with the exposed areas of the photoresist material. That is, after the photoresist layer is exposed to light through a patterned mask, the exposed areas of the photoresist are wet developable and are subsequently removed with an aqueous developer to leave behind the desired trench and hole pattern. Wet developable anti-reflective coatings are removed during this developing step, thus eliminating the need for an additional removal step. Unfortunately, wet developable anti-reflective coatings have not seen widespread use due to the fact that they must also exhibit good spin bowl compatibility and superior optical properties to be useful as an anti-reflective coating. Thus, there is a need for anti-reflective coating compositions which are removed by conventional photoresist developers while simultaneously exhibiting good coating and optical properties.
The present invention broadly comprises microlithographic compositions (and particularly anti-reflective coating compositions) that are useful in the manufacture of microelectronic devices.
In more detail, the compositions comprise a polymer dispersed or dissolved in a solvent system. In one embodiment, the preferred polymers are polyamic acids. The polyamic acids preferably include recurring monomers having the formulas
where each of
individually represent an aryl or aliphatic group.
In this embodiment, the polyamic acids are preferably formed by polymerizing a dianhydride with a diamine. Preferred dianhydrides have the formula
represents an aryl or aliphatic group.
Particularly preferred dianhydrides are:
Preferred diamines have the formula
represents an arly or aliphatic group.
Particularly preferred diamines are:
X=O, S, —CH2, —C(CH3)2, or —C(CF3)2,
n=2-8,
In another preferred embodiment, the preferred polymers include recurring monomers having the formulas
In the foregoing formulas, each R is individually selected from the group consisting of hydrogen, —OH, aliphatics, and phenyls. Preferred aliphatics are C1-C8 branched and unbranched alkyl groups such as t-butyl and isopropyl groups.
L is selected from the group consisting of —SO2— and —CR′2—. When L is —CR′2—, then each R′ is individually selected from the group consisting of hydrogen, aliphatics (preferably C1-C8 branched and unbranched alkyls), and phenyls, and —CX3. In embodiments where R′ is —CX3, each X is individually selected from the group consisting of the halogens, with fluorine and chlorine being the most preferred halogens.
In yet another embodiment, the polymers are formed by polymerizing a compound having the formula
In the formulas of this embodiment, each R is individually selected from the group consisting of —OH, —NH2, hydrogen, aliphatics, and phenyls. Again, as with the first embodiment, preferred aliphatics are C1-C8 branched and unbranched alkyl groups such as t-butyl and isopropyl groups. Furthermore, it is preferred that at least one R on each ring of (I) be —NH2.
L is preferably selected from the group consisting of —SO2— and —CR′2—, where each R′ is individually selected from the group consisting of hydrogen, aliphatics (preferably C1-C8 branched and unbranched alkyl groups), phenyls, and —CX3. When L is —CX3, each X is individually selected from the group consisting of the halogens.
Regardless of the embodiment, the compositions are formed by simply dispersing or dissolving the polymers in a suitable solvent system, preferably at ambient conditions and for a sufficient amount of time to form a substantially homogeneous dispersion. The polymer should be present in the composition at a level of 1-100% by weight, more preferably from about 20-80% by weight, and more preferably from about 40-60% by weight, based upon the total weight of solids in the composition taken as 100% by weight. The weight average molecular weight of this polymer is preferably from about 2,000-1,000,000 Daltons, more preferably from about 5,000-500,000 Daltons, and even more preferably from about 10,000-100,000 Daltons.
Preferred solvent systems include a solvent selected from the group consisting of propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), and mixtures thereof. The solvent system should have a boiling point of from about 50-250° C., and more preferably from about 150-200° C., and should be utilized at a level of from about 50-99% by weight, and preferably from about 90-98% by weight, based upon the total weight of the solids in the composition taken as 100% by weight.
Any other ingredients should be dissolved or dispersed in the solvent system along with the polymer. One such ingredient is a crosslinking agent. Preferred crosslinking agents include aminoplasts (e.g., POWDERLINK® 174, Cymel® products) and epoxies. The crosslinking agent should be present in the composition at a level of from about 0-50% by weight, and preferably from about 10-20% by weight, based upon the total weight of the solids in the composition taken as 100% by weight. Thus, the compositions of the invention should crosslink at a temperature of from about 100-250° C., and more preferably from about 150-200° C.
It is preferred that the compositions also include a light attenuating compound or chromophore. The light attenuating compound should be present in the composition at a level of from about 0-50% by weight, and preferably from about 15-30% by weight, based upon the total weight of solids in the composition taken as 100% by weight. The light attenuating compound should be selected based upon the wavelength at which the compositions will be processed. Thus, at wavelengths of 248 nm, preferred light attenuating compounds include napthalenes and anthracenes, with 3,7-dihydroxy-2-napthoic acid being particularly preferred. At wavelengths of 365 nm, preferred light attenuating compounds include diazo dyes and highly conjugated phenolic dyes. At wavelengths of 193 nm, preferred light attenuating compounds include compounds containing phenyl rings.
The method of applying the inventive compositions to a substrate simply comprises applying a quantity of a composition hereof to the substrate surface by any known application method (including spin-coating). The substrate can be any conventional chip (e.g., silicon wafer) or an ion implant layer.
After the desired coverage is achieved, the resulting layer should be heated to induce crosslinking (e.g., to a temperature of from about 100-250° C.). At a film thickness of about 40 nm and a wavelength of about 248 nm, the cured layers will have a k value (i.e., the imaginary component of the complex index of refraction) of at least about 0.3, and preferably at least about 0.45, and an n value (i.e., the real component of the complex index of refraction) of at least about 1.0, and preferably at least about 1.8. That is, a cured layer formed from the inventive composition will absorb at least about 90%, and preferably at least about 99% of light at a wavelength of about 248 nm. This ability to absorb light at DUV wavelengths is a particularly useful advantage of the inventive compositions.
A photoresist can then be applied to the cured material, followed by exposing, developing, and etching of the photoresist. Following the methods of the invention will yield precursor structures which have the foregoing desirable properties.
It will further be appreciated that the cured inventive composition is wet developable. That is, the cured composition can be removed with conventional aqueous developers such as tetramethyl ammonium hydroxide or potassium hydroxide developers. At least about 90%, and preferably at least about 98% of the inventive coatings will be removed by a base developer such as a tetramethyl ammonium hydroxide developer (e.g., OPD262, available from Olin Photodeveloper). This percent solubility in commercially-available developers is a significant advantage over the prior art as this shortens the manufacturing process and makes it less costly.
Finally, in addition to the many advantages described above, the present composition is spin bowl compatible. This is determined as described in Example 2, using PGMEA as the solvent and taking five measurements to determine the average thicknesses. The percent solubility is calculated as follows:
% solubility = [ ( ave . initial sample thickness - ave . final sample thickness ) ( initial sample thickness ) ] * 100.
The inventive compositions show a percent solubility of at least about 50%, and more preferably at least about 90%.
FIG. 1 is a Scanning Electron Micrograph (SEM) depicting a cross-sectional view of a circuit structure showing how a wet developable anti-reflective layer is removed when the photoresist is developed;
FIG. 2 is an SEM of a cross-section of a circuit structure showing how a conventional thermosetting anti-reflective layer remains when the photoresist is developed; and
FIG. 3 an SEM depicting a cross-sectional view of a circuit structure showing how a wet developable anti-reflective layer according to the invention is removed when the photoresist is developed.
Example 1 Preparation of Anti-Reflective Coating Composition
1. Polymer Preparation
A polyamic acid was produced by combining 4,4′-diaminodiphenyl sulfone (4,4′-DPS), 3,3′-dihydroxybenzidene (HAB), and 4,4′-hexafluoroisopropylidene dipthalic anhydride (6FDA) (each obtained from KrisKev Corporation) at a molar ratio of 0.46:0.46:1. These ingredients were combined at 60° C. in diacetone alcohol (obtained from Aldrich). The mixture was stirred overnight and resulted in a dark brown, viscous liquid having a solids content of 10% by weight.
2. Anti-Reflective Coating Preparation
The ingredients of Table 1 were mixed to yield an anti-reflective coating composition.
Formulation I Percentage By Weighta
Polymer from Part 1 of this Example 1.58%
PGMEAb 48.50%
Diacetone alcohol 48.5%
3,7-dihydroxy-2-napthoic acid 0.95%
Crosslinking Agentc 0.47%
aBased upon the total weight of all ingredients in the composition taken as 100% by weight.
bpropylene glycol monomethyl ether acetate.
cMY720, a tetra functional epoxy resin available from Araldite; diluted 50% by weight in diacetone alcohol
Formulation II Percentage By Weight
Polymer from Part 1 of this Example 1.23%
PGMEA 48.80%
Diacetone alcohol 48.8%
37-dihydroxy-2-napthoic acid 0.74%
Crosslinking Agent 0.43%
Formulation III Percentage By Weight
Polymer from Part 1 of this Example 1.20%
PGMEA 48.50%
3,7-dihydroxy-2-napthoic acid 0.72%
Crosslinking Agent 0.48%
Formulation IV Percentage By Weight
Polymer from Part 1 of this Example 2.25%
PGMEA 47.75%
Diacetone alcohol 47.75%
3,7-dihydroxy-2-napthoic acid 1.35%
Crosslinking Agent 0.90%
Example 2 Testing Methods and Results
1. GPC Analysis
The polymers prepared in Part 1 of this example were analyzed to determine molecular weight using HPLC with an attached gel permeation column where n-methyl pyrillidone with tetrahydrofuran were used as the mobile phase. The polymer prepared in Part 1 of Example 1 had a molecular weight of 24,908 and a molecular number of 13,462.
2. Spin Bowl/Solvent Compatibility Test
Each of the four formulations prepared in Part 2 of Example 1 was subjected to a spin bowl/solvent compatibility test. This test was carried out by spin-coating the composition onto five 4″ silicon wafers for each sample. After spin-coating, the resulting layer was allowed to dry for 24 hours at ambient conditions. At that time, the average initial film thickness on each wafer was determined using a Stokes ellipsometer. After determining the thicknesses, each wafer was soaked with a different solvent (acetone, ethyl lactate, PGMEA, propylene glycol monomethyl ether (PGME), and 2-heptanone) for 180 seconds, followed by spin drying at 3500 rpm. The respective average final film thicknesses were then remeasured using a Stokes ellipsometer. The final thickness measurements of the samples showed that 100% of the anti-reflective coating layers had been removed for each solvent.
3. Film Stripping Test
Each of the anti-reflective coating compositions prepared in Part 2 of Example 1 were subjected to a film stripping test to determine the amount of interaction between typical photoresist solvents and the underlying anti-reflective coating layer. In this test, a 4″ silicon wafer was coated with the particular anti-reflective coating formulation followed by baking at 130° C. for 30 seconds and a second bake at 150° C. for 60 seconds. The film thickness was then measured using a Stokes ellipsometer. After measuring the thickness, the wafer was sprayed with ethyl lactate. The resulting puddle was allowed to stand on the wafer for 10 seconds followed by spin-drying of the wafer at 3500 rpm for 20 seconds. The wafer was then remeasured with a Stokes ellipsometer to determine the film thickness. The amount of stripping is the difference between the initial and final film thickness measurements. The percent stripping is
% stripping = ( amount of stripping initial average film thickness ) × 100.
Compositions according to the invention will give a percent stripping of less than about 20%, and preferably less than about 5%. Each of these formulations exhibited no stripping at bake temperatures of 150-205° C.
4. V.A.S.E. Measurements
In this procedure, 4″ silicon wafers were individually coated with each of the formulations from Part 2 of Example 1. The respective refractive indices (i.e., n value) and imaginary refractive indices (i.e., k value) were determined using variable angle spectrophotometric ellipsometery. Each formulation showed an n value of 1.1 and a k value of 0.45 at 248 nm.
5. Photolithography
The formulations of Part 2 of Example 1 were spin-coated onto respective 8″ silicon substrate at 3500 rpm for 60 seconds, yielding a film having a thickness of 40 nm. The films were then baked at 130° C. for 30 seconds, followed by 175° C. bake for 60 seconds. A commercially available, 500 nm photoresist (SEPR430, available from Shmetsu) was spin-coated on each anti-reflective coating layer followed by a soft bake at 90° C. The photoresist was then patterned with lines and spaces using an ASML 5500/300 stepper with NANA of 0.63 and annular illumination with outer sigma of 0.87 and inner sigma of 0.57. After a KrF excimer laser exposure of 26 mj/cm2, the photoresist was baked at 110° C. for 90 seconds. The photoresist and the anti-reflective coating layer were then developed using a 0.26 N tetramethyl ammonium hydroxide aqueous developer (available under the name OPD262). A cross-sectional view of one of the sample wafers is shown in FIG. 3.
US4742152 May 27, 1986 May 3, 1988 United Technologies Corporation High temperature fluorinated polyimides
US4803147 Nov 24, 1987 Feb 7, 1989 Hoechst Celanese Corporation Photosensitive polyimide polymer compositions
US4927736 Jul 21, 1987 May 22, 1990 Hoechst Celanese Corporation Hydroxy polyimides and high temperature positive photoresists therefrom
US5089593 Dec 22, 1989 Feb 18, 1992 Amoco Corporation Polyimide containing 4,4'-bis(4-amino-2-trifluoromethylphenoxy)-biphenyl moieties
US5304626 Sep 13, 1991 Apr 19, 1994 Amoco Corporation Polyimide copolymers containing 3,3',4,4'-tetracarboxybiphenyl dianhydride (BPDA) moieties
US5340684 * Nov 29, 1993 Aug 23, 1994 Kabushiki Kaisha Toshiba Photosensitive composition and resin-encapsulated semiconductor device
US5397684 Apr 27, 1993 Mar 14, 1995 International Business Machines Corporation Antireflective polyimide dielectric for photolithography
US5688987 Nov 9, 1994 Nov 18, 1997 Brewer Science, Inc. Non-subliming Mid-UV dyes and ultra-thin organic arcs having differential solubility
US5772925 Jul 10, 1997 Jun 30, 1998 Shin-Etsu Chemical Co., Ltd. Anti-reflective coating composition
US5892096 Feb 8, 1996 Apr 6, 1999 Brewer Science, Inc. Non-subliming mid-UV dyes and ultra-thin organic arcs having differential solubility
US5952448 Dec 30, 1997 Sep 14, 1999 Korea Research Institute Of Chemical Technology Stable precursor of polyimide and a process for preparing the same
US5998569 Mar 17, 1998 Dec 7, 1999 International Business Machines Corporation Environmentally stable optical filter materials
US20020120091 * Feb 15, 2002 Aug 29, 2002 Lisa Scott Poly amic acid system for polyimides
US20020160211 * Aug 2, 2001 Oct 31, 2002 Tomoharu Kurita Flexible metal-clad laminate and process for preparing the same
US20040010062 * Sep 27, 2002 Jan 15, 2004 Byeong-In Ahn Polyimide copolymer and methods for preparing the same
JPS48891U * Title not available
1 * Derwent abstract of JP 48-891.
2 * DN 78:112161 CAplus abstract of JP 48000891, Jan. 1993.
3 Translation of JP Pub No. JP 10307394.
US8053368 Mar 26, 2008 Nov 8, 2011 International Business Machines Corporation Method for removing residues from a patterned substrate
US8877430 Aug 4, 2011 Nov 4, 2014 Brewer Science Inc. Methods of producing structures using a developer-soluble layer with multilayer technology
US20090246958 * Mar 26, 2008 Oct 1, 2009 International Business Machines Corporation Method for removing residues from a patterned substrate
US20100040988 * Oct 20, 2009 Feb 18, 2010 Robert Christian Cox Spin bowl compatible polyamic acids/imides as wet developable polymer binders for anti-reflective coatings
U.S. Classification 430/271.1, 430/905, 528/391, 528/230, 430/325, 528/173, 430/326, 528/171, 528/170
International Classification H01L21/027, G03F7/037, G02B1/11, G03C5/00, G03F7/09, G03F7/038, G03F7/11, C08G73/10
Cooperative Classification Y10S430/106, Y10S430/151, G02B1/111, C09D179/08, C08G73/10, C08G73/1064, C08G73/1039, G03F7/091, C08G73/1025, G03F7/038
European Classification C09D179/08, G03F7/09A, C08G73/10M2, G02B1/11B, C08G73/10F, C08G73/10B1P, C08G73/10, G03F7/038
Owner name: BREWER SCIENCE, INC., MISSOURI
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:COX, ROBERT CHRISTIAN;NEEF, CHARLES J.;REEL/FRAME:013254/0976