CA2090039A1 - Top coat and acid catalyzed resists - Google Patents
Top coat and acid catalyzed resistsInfo
- Publication number
- CA2090039A1 CA2090039A1 CA 2090039 CA2090039A CA2090039A1 CA 2090039 A1 CA2090039 A1 CA 2090039A1 CA 2090039 CA2090039 CA 2090039 CA 2090039 A CA2090039 A CA 2090039A CA 2090039 A1 CA2090039 A1 CA 2090039A1
- Authority
- CA
- Canada
- Prior art keywords
- acid
- polymeric film
- resist
- film forming
- protective topcoat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
- G03F7/092—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers characterised by backside coating or layers, by lubricating-slip layers or means, by oxygen barrier layers or by stripping-release layers or means
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Structural Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
- Management, Administration, Business Operations System, And Electronic Commerce (AREA)
Abstract
A protective material for use as an overcoating film for acid catalyzed resist compositions comprising a polymeric film forming compound, the films of which are impermeable to vapors of organic and inorganic bases.
Description
WO 92~0!S474 P~/U~;~0/0761~ l ~09003~
~roP COAT FOR ACID CAI'ALYZED RESISTS
;
Background of the Invention 1. Field of the Invention The inYention relates to acid catalyzed resist formulations. More particularly, the present invention is concerned with a protective topcoat material for use as an overcoating film Eor acid catalyzed resist compositions.
..
~roP COAT FOR ACID CAI'ALYZED RESISTS
;
Background of the Invention 1. Field of the Invention The inYention relates to acid catalyzed resist formulations. More particularly, the present invention is concerned with a protective topcoat material for use as an overcoating film Eor acid catalyzed resist compositions.
..
2. ~ackground Art 10The problem of protecting materials from gaseous contamination is one of long standing. The solution :. has generally been to provide a coating or encapsulation with a material which is impervious to . the deleterious gas.
i 15U.S. Patent No. 3,753,715 discloses the use of :3, , certain water soluble macromolecular organic polymers . : in controlling oxygen diffusion in photopolymerizable copying process. The barrier materials include polyvinyl alcohol and its partial esters, and partial '5 20 acetals, as well as other natural and synthetic . materi~ls of higher molecular weights such as ; gelatin, ~um arabic, copolymer of methylvinyl ether and maleic anhydride, polyvinyl pyrrGlidones, and water soluble polymers of ethylene oxide with ~ 25 molecular weights in the range from lO0,000 to sl 3,000,000. rfletti~g agents in relatively small ' 3 quantities have been included in such aqueous coating solutions. The drawbacks of suc}l barrier materials (at least as they apply to photopolymerization ~l 30 copying) include the necessity for certain minimum , : :
.
W092/~4 P~T/US90/07618 ~90~3g drying times to form homogeneous coatings and the impermeability of the layers to light that an effective oxygen transfer cannot be maintained.
U.S. Patent No. 3,652,273 discloses the use of polyvinyl butyral as a topcoat for photoresist. This topcoat provides protection against oxygen and high humidity and results in less scumming of and pinholing in the hydrophobic resist. The topcoat film is soluble in the developer and does not interfere with imaging.
U.S. Patent No. 4,756,988 discloses tl-e use of a non-photosensitive crosslinkable adhesive layer to ;provide performance improvements in the areas of ~,resistance to crazing of the film during storage, -15 photosensitivity in that the pho~ospeed is increased to make the films more processable, enabling the fabrication of photoresists without using alkoxysilane adhesion promoters, ~and improving thermal dimensional stability of the film during plating and etching processes. The topcoat compositions include terpolymers of ethylacrylate, methylacrylate and acrylic acid.
I~M Technical Disclosurs Bulletin, Vol. 12, No.
9, pp. 141~-19, discloses the use of azidosulfono-stilbene ~ilms as a topcoat to prevent oxygen diffusion into photoresist films to consume sensitizer radicals. The polyvinyl acetate impedes oxygen difusionO
Japanese Patent Publication 58-17834~ is ;30 direc~ed to a proce~s for forming imagss by exposing ~a photosensitivP material prepare~ by coating a , ' ' .
W092/0~74 PCr/US90/076l8 _ ~it;, ~09~39 substxate with a photosensitive layer and a protective layer of polyvinyl alcohol which is water insoluble but is water swellable after exposure to light, removing the polyvinyl alcohol layer with water and developing the phot~sensitive layer.
European Patent Application 0160468 is directed to the use of a number of materials including polyethylene oxide as a protective topcoat against ozone generated in a flexographic printing process.
The use of this topcoat leads to the improved adhesion of i~ks to corona treated cardboard.
Japanese Patent Publication No. 60 200249 relates to the use of a polyvinyl alcohol as an antisticking layer between a topcoat layer and a photosensitive layer on a substrate.
IBM Technical Disclosure Bulletin Vol. 27, No.
11, April 1985, p 6521 discloses the use of polyvinyl alcohol as a top depth of-focus enhancement layer owing to the optical properties of the polyvinvl alcohol film. No suggestion of barrier properties is ` made.
.~.
.
~ cid catalyzed resists are based upon mechanisms which involve the radiation induced generation of a Lewis or ~ronsted acid from acid precursors such as sulfonates and triflates of onium salts and oxime and dicarboximide derivatives. The radiation induced ' formation of acid catalyzes the decarbonylation of i the rlesist such as the poly-p-tertbutyloxycarbonyloxystyrene compositions as set orth in U.S. Paten~ No. 4,491,628. Other acid i cataIy2ed reactions include the cleaving of diacetals t ~ , :1 ,, ~`
WQ92/~74 P~r/USgO/076l8 æo90039 of novolaks and the acid catalyzed crosslinking of epoxy and melamine based resists. Although acid catalyzed image amplified resist are very reactive compositions, i.e., they have a high photospeed, they also exhibit an extreme sensitivity to environmental chemicals present in .the process areas, even when they are pre~ent only at the p.p.b. level. If wafers havlng an imaged and exposed acid catalyzed resist such as poly-p-tertbutyloxycarbonyloxystyrene are ; 10 left open to process air, they suffer from profile deterioration and eventually no discernible images will be for~ed. The desensitization o~ the resist is believed to be due to the poisoning of the acid generator and the acids formed by the absorption of vapors of organic amines and/or inorganic bases.
Controll~d laboratory experlments in which chemically amplified resist compositions were - prepared using trifluoromethylsulfonyloxy bicyclo~2.2.1]-hept-5-ene-2,3-dicarboximide (hereinafter MDT) which i5 disclosed in U.S. Patent ~pplication, Serial No.07/322,848 filed March 14, 1989 a~ the sensitizer and on one hand poly-p-tertbutyloxycarbonyloxystyrene and on the other poly-p-hydroxystrene-p-tertbutyloxycarbonyloxystyrene. These compositions were exposed to pph levels of organic vapors of . N-methyl-2-pyrrolidone(NMP)~ ammonia, pyridine and triethylamine and rapid desensitization of the resists was noted. .Since these resists are sensitive to organic vapors at the ppb levels, it is not practical or economical to remove all of these vapors from a manllfacturing process area or from inside of those tools, designed to operate at atmospheric ; conditions. Additionally, a wafer may be e:cpose~ to ., .
wo sa/os~74 PCr/U590/1)7618 2~900~9 process air for up to 15 minutes inside a deep UV
stepper or scanning tool. Different portions of large wafers, e.g., 200 mm diameter wafers may experience different periods of exposure to process air. Desensiti~ation may cauc;e certain portions of the wafer to be undeveloped or have localized distorted images.
We have found that the application of a thin (about 1200 Angstroms) barrier layer on top o~ an acid sensitized, environmentally sensitive resist provides adequate short term protection (up to 24 hours) ~or such resist even when it is processecl in atmospheres having an organic amine or NMP vapor `,concentration greater than or equal to 1 part per million, The barrier layer has also been found to increase the sensitivity of coated acid sensitized resists when such resists are used in electron beam tools. Uncoated resists tend to experience an , ., -` 20 outgassing of acid and acid-degraded fragments due to their partial pressures. The use of the barrier ~, inhibits the removal of acid from the resist film and, therefore, enhances the effect of the acid in prom~tin~ e ~atterne~ exposure.
~' Barrier topcoats have been previously used to protect free radical based resist systems which are oxygen sensit7ve. These include a 25 um Mylar film ~`~ on DuPont Riston acrylate crosslinking resist and the use of 2 um Eilm o~ poly~inylalcohol on top of a free radical polyolein sulfone-novolak based x-ray resist. For such uses, fil~s of polyvinylalcohol thinner than about 0.5~m does not function as an :,~
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~:
, . .
~.
:,;
W092/0~74 PCT/US90/07618 2 Q 9 ~ Or~9 ~
-6- `
effective oxygen barrier topcoat. The thicker barriers are thought to prevent oxygen from diffusing into the exposed resist films and consuming some or all of the xadical initiators. Topcoats which inhibit oxygen poisoning of radical systems are not inherently useful in the inhibition or "poisoning" of acid ba~ed resist systems which are quite tol~rant o~
oxygen. To be effective, a topcoat has to be compatible with the particular resist protected and designed to prevent deleterious vapor phase reactions. In the case of acid catalyzed resists ;entailing the cleavage of an acid la~ile protecting group from a reactive functional site, the acid initiator cause the production of a large amount of gaseous products. A protective topcoat has to be thin and permeable in order to allow the gaseous reaction products formed during post exposure bake to diffuse through the resist and the topcoat film without bubble formation or distortion of the underlying resist.
Some considerations which contribute to the -~usefulnes~ of polyacrylic acid as topcoat are:
(1) a low molecular weight < 5000 (Higher molecular weights caused blistering in postexposure bake of par~ially t-butylcarboxylated poly-p-hydroxystyrene~;
(2) a low sodi~m metal or ammonium ion content ~ 100 ppm~ Metallic or basic im~uritie~ in topcoat can desensitize the acid formed during exposure;
~3) an acid p}l level ~ 2 to prevent undesired . 30 acidolysis o~ the undexlying resist during prebake;
. ~ .
WO9~ 74 PCT/US~0/0761~
20~003!) (4) optical transparency in the deep UV: Absorb-ence ~n. 1 before or during exposure:
(5) a rapid dissolution in alkaLine developer, ~6) upper film thickness limit of about 200 nm to prevent blistering of the acid ci~talyzed resist which evolve gases.
5imilar properties for polyvinylbutyral topcoat were noted.
Example 1 - A lum film on silicon wafer of an acid catalyzed resist comprising poly-p-tertbutyloxycarbonyloxystyrene resist containing 4~
by weight of triphenysulfonium hexafluoroantimonate made in accordance with the method set forth in U.S.
Patent 4,491,628 was exposed on Perkin-Elmer deep UV
scanner (200-290 nm exposure band) and left standing for several minutes in a lab before post-exposure bakin~. After post expose baking and development in anisole, the 1 ~m lines of resist images were found to have overhanging "T" shapes. A companion wafer processed with a topcoat of 100 nm of polyvinylbutyral cast from butanol was found to form good straight wall profiles without "T" overhangs.
, When the uncoated resist was exposed to longer periods of time of process air t25 hours) no imaqes were formed in the uncoated resist film and only - slight traces of overhang formation in the polyvinylbut~ral topcoated acid catalyzed resist. A
protection ~ime of 30 minutes is considered adequate ~or e~en ~he slowest e~posure tools.
~ , .
., .
.
WO~2/0~7q PCT/US90/0761~ I
2~9003~ I
Example 2 - A l.O~m film on silicon wafer of an acid catalyzed resist comprising a partially t-butyloxycarbonyloxylated poly-p-hydroxystyrene sensitized with 8% MDT was e.xposed by Perkin-Elmer deep UV scanner and left in lab air for fifteen minutes prior to postexpose baking and developing in 0.25N alkaline T~AH. No images were formed. A
second film of prebaked partialiy t-butyloxycarbonyloxylated poly-p-hydroxystyrene was overcoated with a lOUnm (O.l~m) topcoat of polyacrylic acid cast from 6~ by weight water based system and dried for 3 minutes at 90C. The film was exposed and processed in a similar manner. Good 1 ~m profiles were formed.
Example 3 -- A l.O~m film on a silicon wafer of the partially t-butyloxycarbonyloxylated :~poly-p-hydroxystyrene sensitized with MDT was exposed at 2.5 ~cJcm2 with a 25 KeV electrons. A faint image which was not developed out was formed. A similar partially t-butyloxycarbonyloxylated poly-p-hydroxystyrene with a 150nm topcoat of polyacrylic acid processed in a similar manner gave good 0.5~m profiles.
E~ample 4 - A l.O~m film on silicon of Ray PF
llloecllst, positive to~e acid catalyzed resist3 was exposed to x rays under partial va~uum conditions. A
dose of 60 mJ/cm2 was required to resolve images and the smallest feature resolved was a 0.75~m line/space arxay. A similar film overcoated with 0~12~m of ~~0 poly(acrylic acid~ required a ~ose of 20mJ/cm2 to -resolve images and the smallest feature on the mask (0.25~m spac~ ~ 0.50~m line) was resolved.
The following t~hles show the usefulness of some :~, .
... . . .....
W092/~74 PCT/VS~/0761~ ¦
_g_ topcoat materials with specific acid catalyzed resists.
TABLE 1 ~ Partially t-Butyloxycarhonyloxylated poly-p-hydroxYstyrene Resist Polyacrylic acid 24 hrs protect, no blister Polyvinyl AlCOhOl 15-20 min protect, slight blister and image residues after development Polyvinylpyrrolidone no protection, desensitization Polystyrene sulfonic no protection, acid NH4 desensitization Polystyrene sulfonic good protection as acid effective as I polyacrylic acid (pH has to be above 2) .1 - Polymethacrylic acid blistering .
...
.
....
Q ' ';' ., W0~2J~74 PCT/US90J076~8 ~i 20~003~
TABLE 2 - ~~Bu~ ox~carbonYloxystyrene ~eslst TOPCOAT PERFORrlANCE
Polyvinylbutyral 24 hr protection Novolak resin limited protection ~ 5 ( 20 minl;
: image residues Polybutylmethacrylate limited protection (10 min) Thus, different resist and topcoa~ combination are selected to provide protection of acid sensitive resist with a minimum of one extra coat and bake process step.
While only the preferred embodiments of the present invention are described above, many potenti~l modifications which fall within the generic conc~pt . will occur ~o those skilled in the art upon a reading ' of the present discl~sure. Such modi~ications in ', terms of topcoat polymeric materials which have the properties and performances as here set forth are . 20 Wit}lin the teaching of the present invention and within its ~cope as set forth in the claims which ollow.
.`
j: What is Claimed is:
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.. . .
i 15U.S. Patent No. 3,753,715 discloses the use of :3, , certain water soluble macromolecular organic polymers . : in controlling oxygen diffusion in photopolymerizable copying process. The barrier materials include polyvinyl alcohol and its partial esters, and partial '5 20 acetals, as well as other natural and synthetic . materi~ls of higher molecular weights such as ; gelatin, ~um arabic, copolymer of methylvinyl ether and maleic anhydride, polyvinyl pyrrGlidones, and water soluble polymers of ethylene oxide with ~ 25 molecular weights in the range from lO0,000 to sl 3,000,000. rfletti~g agents in relatively small ' 3 quantities have been included in such aqueous coating solutions. The drawbacks of suc}l barrier materials (at least as they apply to photopolymerization ~l 30 copying) include the necessity for certain minimum , : :
.
W092/~4 P~T/US90/07618 ~90~3g drying times to form homogeneous coatings and the impermeability of the layers to light that an effective oxygen transfer cannot be maintained.
U.S. Patent No. 3,652,273 discloses the use of polyvinyl butyral as a topcoat for photoresist. This topcoat provides protection against oxygen and high humidity and results in less scumming of and pinholing in the hydrophobic resist. The topcoat film is soluble in the developer and does not interfere with imaging.
U.S. Patent No. 4,756,988 discloses tl-e use of a non-photosensitive crosslinkable adhesive layer to ;provide performance improvements in the areas of ~,resistance to crazing of the film during storage, -15 photosensitivity in that the pho~ospeed is increased to make the films more processable, enabling the fabrication of photoresists without using alkoxysilane adhesion promoters, ~and improving thermal dimensional stability of the film during plating and etching processes. The topcoat compositions include terpolymers of ethylacrylate, methylacrylate and acrylic acid.
I~M Technical Disclosurs Bulletin, Vol. 12, No.
9, pp. 141~-19, discloses the use of azidosulfono-stilbene ~ilms as a topcoat to prevent oxygen diffusion into photoresist films to consume sensitizer radicals. The polyvinyl acetate impedes oxygen difusionO
Japanese Patent Publication 58-17834~ is ;30 direc~ed to a proce~s for forming imagss by exposing ~a photosensitivP material prepare~ by coating a , ' ' .
W092/0~74 PCr/US90/076l8 _ ~it;, ~09~39 substxate with a photosensitive layer and a protective layer of polyvinyl alcohol which is water insoluble but is water swellable after exposure to light, removing the polyvinyl alcohol layer with water and developing the phot~sensitive layer.
European Patent Application 0160468 is directed to the use of a number of materials including polyethylene oxide as a protective topcoat against ozone generated in a flexographic printing process.
The use of this topcoat leads to the improved adhesion of i~ks to corona treated cardboard.
Japanese Patent Publication No. 60 200249 relates to the use of a polyvinyl alcohol as an antisticking layer between a topcoat layer and a photosensitive layer on a substrate.
IBM Technical Disclosure Bulletin Vol. 27, No.
11, April 1985, p 6521 discloses the use of polyvinyl alcohol as a top depth of-focus enhancement layer owing to the optical properties of the polyvinvl alcohol film. No suggestion of barrier properties is ` made.
.~.
.
~ cid catalyzed resists are based upon mechanisms which involve the radiation induced generation of a Lewis or ~ronsted acid from acid precursors such as sulfonates and triflates of onium salts and oxime and dicarboximide derivatives. The radiation induced ' formation of acid catalyzes the decarbonylation of i the rlesist such as the poly-p-tertbutyloxycarbonyloxystyrene compositions as set orth in U.S. Paten~ No. 4,491,628. Other acid i cataIy2ed reactions include the cleaving of diacetals t ~ , :1 ,, ~`
WQ92/~74 P~r/USgO/076l8 æo90039 of novolaks and the acid catalyzed crosslinking of epoxy and melamine based resists. Although acid catalyzed image amplified resist are very reactive compositions, i.e., they have a high photospeed, they also exhibit an extreme sensitivity to environmental chemicals present in .the process areas, even when they are pre~ent only at the p.p.b. level. If wafers havlng an imaged and exposed acid catalyzed resist such as poly-p-tertbutyloxycarbonyloxystyrene are ; 10 left open to process air, they suffer from profile deterioration and eventually no discernible images will be for~ed. The desensitization o~ the resist is believed to be due to the poisoning of the acid generator and the acids formed by the absorption of vapors of organic amines and/or inorganic bases.
Controll~d laboratory experlments in which chemically amplified resist compositions were - prepared using trifluoromethylsulfonyloxy bicyclo~2.2.1]-hept-5-ene-2,3-dicarboximide (hereinafter MDT) which i5 disclosed in U.S. Patent ~pplication, Serial No.07/322,848 filed March 14, 1989 a~ the sensitizer and on one hand poly-p-tertbutyloxycarbonyloxystyrene and on the other poly-p-hydroxystrene-p-tertbutyloxycarbonyloxystyrene. These compositions were exposed to pph levels of organic vapors of . N-methyl-2-pyrrolidone(NMP)~ ammonia, pyridine and triethylamine and rapid desensitization of the resists was noted. .Since these resists are sensitive to organic vapors at the ppb levels, it is not practical or economical to remove all of these vapors from a manllfacturing process area or from inside of those tools, designed to operate at atmospheric ; conditions. Additionally, a wafer may be e:cpose~ to ., .
wo sa/os~74 PCr/U590/1)7618 2~900~9 process air for up to 15 minutes inside a deep UV
stepper or scanning tool. Different portions of large wafers, e.g., 200 mm diameter wafers may experience different periods of exposure to process air. Desensiti~ation may cauc;e certain portions of the wafer to be undeveloped or have localized distorted images.
We have found that the application of a thin (about 1200 Angstroms) barrier layer on top o~ an acid sensitized, environmentally sensitive resist provides adequate short term protection (up to 24 hours) ~or such resist even when it is processecl in atmospheres having an organic amine or NMP vapor `,concentration greater than or equal to 1 part per million, The barrier layer has also been found to increase the sensitivity of coated acid sensitized resists when such resists are used in electron beam tools. Uncoated resists tend to experience an , ., -` 20 outgassing of acid and acid-degraded fragments due to their partial pressures. The use of the barrier ~, inhibits the removal of acid from the resist film and, therefore, enhances the effect of the acid in prom~tin~ e ~atterne~ exposure.
~' Barrier topcoats have been previously used to protect free radical based resist systems which are oxygen sensit7ve. These include a 25 um Mylar film ~`~ on DuPont Riston acrylate crosslinking resist and the use of 2 um Eilm o~ poly~inylalcohol on top of a free radical polyolein sulfone-novolak based x-ray resist. For such uses, fil~s of polyvinylalcohol thinner than about 0.5~m does not function as an :,~
~"' .
~:
, . .
~.
:,;
W092/0~74 PCT/US90/07618 2 Q 9 ~ Or~9 ~
-6- `
effective oxygen barrier topcoat. The thicker barriers are thought to prevent oxygen from diffusing into the exposed resist films and consuming some or all of the xadical initiators. Topcoats which inhibit oxygen poisoning of radical systems are not inherently useful in the inhibition or "poisoning" of acid ba~ed resist systems which are quite tol~rant o~
oxygen. To be effective, a topcoat has to be compatible with the particular resist protected and designed to prevent deleterious vapor phase reactions. In the case of acid catalyzed resists ;entailing the cleavage of an acid la~ile protecting group from a reactive functional site, the acid initiator cause the production of a large amount of gaseous products. A protective topcoat has to be thin and permeable in order to allow the gaseous reaction products formed during post exposure bake to diffuse through the resist and the topcoat film without bubble formation or distortion of the underlying resist.
Some considerations which contribute to the -~usefulnes~ of polyacrylic acid as topcoat are:
(1) a low molecular weight < 5000 (Higher molecular weights caused blistering in postexposure bake of par~ially t-butylcarboxylated poly-p-hydroxystyrene~;
(2) a low sodi~m metal or ammonium ion content ~ 100 ppm~ Metallic or basic im~uritie~ in topcoat can desensitize the acid formed during exposure;
~3) an acid p}l level ~ 2 to prevent undesired . 30 acidolysis o~ the undexlying resist during prebake;
. ~ .
WO9~ 74 PCT/US~0/0761~
20~003!) (4) optical transparency in the deep UV: Absorb-ence ~n. 1 before or during exposure:
(5) a rapid dissolution in alkaLine developer, ~6) upper film thickness limit of about 200 nm to prevent blistering of the acid ci~talyzed resist which evolve gases.
5imilar properties for polyvinylbutyral topcoat were noted.
Example 1 - A lum film on silicon wafer of an acid catalyzed resist comprising poly-p-tertbutyloxycarbonyloxystyrene resist containing 4~
by weight of triphenysulfonium hexafluoroantimonate made in accordance with the method set forth in U.S.
Patent 4,491,628 was exposed on Perkin-Elmer deep UV
scanner (200-290 nm exposure band) and left standing for several minutes in a lab before post-exposure bakin~. After post expose baking and development in anisole, the 1 ~m lines of resist images were found to have overhanging "T" shapes. A companion wafer processed with a topcoat of 100 nm of polyvinylbutyral cast from butanol was found to form good straight wall profiles without "T" overhangs.
, When the uncoated resist was exposed to longer periods of time of process air t25 hours) no imaqes were formed in the uncoated resist film and only - slight traces of overhang formation in the polyvinylbut~ral topcoated acid catalyzed resist. A
protection ~ime of 30 minutes is considered adequate ~or e~en ~he slowest e~posure tools.
~ , .
., .
.
WO~2/0~7q PCT/US90/0761~ I
2~9003~ I
Example 2 - A l.O~m film on silicon wafer of an acid catalyzed resist comprising a partially t-butyloxycarbonyloxylated poly-p-hydroxystyrene sensitized with 8% MDT was e.xposed by Perkin-Elmer deep UV scanner and left in lab air for fifteen minutes prior to postexpose baking and developing in 0.25N alkaline T~AH. No images were formed. A
second film of prebaked partialiy t-butyloxycarbonyloxylated poly-p-hydroxystyrene was overcoated with a lOUnm (O.l~m) topcoat of polyacrylic acid cast from 6~ by weight water based system and dried for 3 minutes at 90C. The film was exposed and processed in a similar manner. Good 1 ~m profiles were formed.
Example 3 -- A l.O~m film on a silicon wafer of the partially t-butyloxycarbonyloxylated :~poly-p-hydroxystyrene sensitized with MDT was exposed at 2.5 ~cJcm2 with a 25 KeV electrons. A faint image which was not developed out was formed. A similar partially t-butyloxycarbonyloxylated poly-p-hydroxystyrene with a 150nm topcoat of polyacrylic acid processed in a similar manner gave good 0.5~m profiles.
E~ample 4 - A l.O~m film on silicon of Ray PF
llloecllst, positive to~e acid catalyzed resist3 was exposed to x rays under partial va~uum conditions. A
dose of 60 mJ/cm2 was required to resolve images and the smallest feature resolved was a 0.75~m line/space arxay. A similar film overcoated with 0~12~m of ~~0 poly(acrylic acid~ required a ~ose of 20mJ/cm2 to -resolve images and the smallest feature on the mask (0.25~m spac~ ~ 0.50~m line) was resolved.
The following t~hles show the usefulness of some :~, .
... . . .....
W092/~74 PCT/VS~/0761~ ¦
_g_ topcoat materials with specific acid catalyzed resists.
TABLE 1 ~ Partially t-Butyloxycarhonyloxylated poly-p-hydroxYstyrene Resist Polyacrylic acid 24 hrs protect, no blister Polyvinyl AlCOhOl 15-20 min protect, slight blister and image residues after development Polyvinylpyrrolidone no protection, desensitization Polystyrene sulfonic no protection, acid NH4 desensitization Polystyrene sulfonic good protection as acid effective as I polyacrylic acid (pH has to be above 2) .1 - Polymethacrylic acid blistering .
...
.
....
Q ' ';' ., W0~2J~74 PCT/US90J076~8 ~i 20~003~
TABLE 2 - ~~Bu~ ox~carbonYloxystyrene ~eslst TOPCOAT PERFORrlANCE
Polyvinylbutyral 24 hr protection Novolak resin limited protection ~ 5 ( 20 minl;
: image residues Polybutylmethacrylate limited protection (10 min) Thus, different resist and topcoa~ combination are selected to provide protection of acid sensitive resist with a minimum of one extra coat and bake process step.
While only the preferred embodiments of the present invention are described above, many potenti~l modifications which fall within the generic conc~pt . will occur ~o those skilled in the art upon a reading ' of the present discl~sure. Such modi~ications in ', terms of topcoat polymeric materials which have the properties and performances as here set forth are . 20 Wit}lin the teaching of the present invention and within its ~cope as set forth in the claims which ollow.
.`
j: What is Claimed is:
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... .
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.. . .
Claims (12)
1. A protective topcoat material for use as an overcoating film for an acid catalyzed resist composition which comprises a polymeric film forming compound, thin films of which are sufficiently impermeable to vapors of organic and inorganic bases to prevent desensitization of the resist composition.
2. The protective topcoat material of claim 1 which is selected from the group consisting of polyacrylic acid, polyvinyl butyral, polyvinyl alcohol, and polystyrene sulfonic acid.
3. The protective topcoat material of claim 2 which has a molecular weight of from about 1000 to 5000.
4. The protective topcoat material of claim 3 which is polyacrylic acid.
5. The method of protecting acid catalyzed resist compositions from contamination by vapors of organic or inorganic bases comprising the steps of (a) coating a substrate with a layer of an acid catalyzed resist composition, (b) overcoating the layer of acid catalyzed resist composition with a thin film of a polymeric film forming composition which is sufficiently impermeable to organic and inorganic basis to prevent desensitization of the resist composition.
6. The method of claim 5 wherein the polymeric film forming composition is selected from the group consisting of polyacrylic acid, polyvinyl butyral, polyvinyl alcohol, and polystyrene sulfonic acid.
7. The method of claim 6 wherein the polymeric film forming composition has a molecular weight of from about 1000 to 5000.
8. The method of claim 6 wherein the polymeric film is applied in a thickness of from about 500 to 5000 Angstroms.
9. A protective topcoat for an acid catalyzed resist composition which comprises a thin film of a polymeric film forming composition which is sufficiently impermeable to vapors of organic and inorganic bases to prevent desensitization of the resist composition.
10. The protective topcoat of claim 9 wherein the polymeric film forming composition is selected from the group consisting of polyacrylic acid, polyvinyl butyral, polyvinyl alcohol, and polystyrene sulfonic acid.
11. The protective topcoat of claim 10 wherein the polymeric film forming composition has a molecular weight from about 1000 to 5000.
12. The protective topcoat of claim 9 wherein the thickness of the thin film of the polymeric film forming composition is from about 500 to 5000 Angstroms.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US58727390A | 1990-09-18 | 1990-09-18 | |
US587,273 | 1990-09-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2090039A1 true CA2090039A1 (en) | 1992-03-19 |
Family
ID=24349129
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA 2090039 Abandoned CA2090039A1 (en) | 1990-09-18 | 1990-12-21 | Top coat and acid catalyzed resists |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0556177A1 (en) |
JP (1) | JPH05507154A (en) |
CA (1) | CA2090039A1 (en) |
WO (1) | WO1992005474A1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5506090A (en) * | 1994-09-23 | 1996-04-09 | Minnesota Mining And Manufacturing Company | Process for making shoot and run printing plates |
KR100401116B1 (en) * | 1999-06-03 | 2003-10-10 | 주식회사 하이닉스반도체 | Amine contamination-protecting material and a fine pattern forming method using the same |
US6984482B2 (en) | 1999-06-03 | 2006-01-10 | Hynix Semiconductor Inc. | Top-coating composition for photoresist and process for forming fine pattern using the same |
DE102004030861A1 (en) * | 2004-06-25 | 2006-01-19 | Infineon Technologies Ag | Structuring a semiconductor substrate in a lithographic manner comprises preparing a semiconductor substrate, applying a first layer containing a photoresist and further processing |
WO2006059555A1 (en) | 2004-12-03 | 2006-06-08 | Jsr Corporation | Composition for forming antireflection film, layered product, and method of forming resist pattern |
JP4595606B2 (en) | 2005-03-17 | 2010-12-08 | Jsr株式会社 | Antireflection film forming composition, laminate, and resist pattern forming method |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS50152803A (en) * | 1974-05-29 | 1975-12-09 | ||
JPS57183030A (en) * | 1981-05-07 | 1982-11-11 | Toshiba Corp | Manufacture of semiconductor device |
DE3715790A1 (en) * | 1987-05-12 | 1988-11-24 | Hoechst Ag | RADIATION-SENSITIVE RECORDING MATERIAL |
-
1990
- 1990-12-21 EP EP19910906782 patent/EP0556177A1/en not_active Withdrawn
- 1990-12-21 WO PCT/US1990/007618 patent/WO1992005474A1/en not_active Application Discontinuation
- 1990-12-21 JP JP91507106A patent/JPH05507154A/en active Pending
- 1990-12-21 CA CA 2090039 patent/CA2090039A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
JPH05507154A (en) | 1993-10-14 |
WO1992005474A1 (en) | 1992-04-02 |
EP0556177A1 (en) | 1993-08-25 |
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