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Patent US5968712 - Radiation sensitive compositions and methods - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsThe present invention provides radiation sensitive compositions and methods that comprise novel means for providing relief images of enhanced resolution. In one aspect the invention provides a method for controlling diffusion of photogenerated acid comprising adding a polar compound to a radiation sensitive...http://www.google.com/patents/US5968712?utm_source=gb-gplus-sharePatent US5968712 - Radiation sensitive compositions and methodsAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS5968712 APublication typeGrantApplication numberUS 08/152,084Publication dateOct 19, 1999Filing dateNov 12, 1993Priority dateOct 17, 1991Fee statusPaidAlso published asEP0537524A1, US6607870, US6727049, US7060413, US7166414, US20010038964, US20030203310, US20040161699, US20060051706Publication number08152084, 152084, US 5968712 A, US 5968712A, US-A-5968712, US5968712 A, US5968712AInventorsJames W. Thackeray, Angelo A. LamolaOriginal AssigneeShipley Company, L.L.C.Export CitationBiBTeX, EndNote, RefManPatent Citations (15), Non-Patent Citations (40), Referenced by (45), Classifications (29), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetRadiation sensitive compositions and methods
5. The method of claim 1 wherein the photoresist layer is heated at 90° C. or less after the forming and prior to the exposing, and the aliphatic amine is not volatized from the photoresist layer during the heating at 90° C. or less.
The polar compounds useful in the invention are characterized by having one or more moieties that can complex with photogenerated acid. A complex of the polar compound and acid should release an activating amount of acid upon heating at temperatures of the post exposure bake to effect the desired acid-catalyzed reaction. Typically post exposure bake temperatures range from about 50° C. or greater. Hence a complex of photogenerated acid and the polar compound suitably releases an activating amount of acid at about 50° C. or greater. Post exposure bakes of 80° C., 100° C., 110° C., 120° C., 140° C. or greater are common; therefore release of an activating amount of acid at any of these temperatures or greater can be suitable.
It is common to perform a pre-exposure bake after coating a liquid photosensitive composition on a surface to remove solvents. Such a pre-exposure bake is typically conducted at temperatures of 90° C. or less. It is thus preferred that a sufficient amount of the polar compound remain disposed within a radiation sensitive composition, and not be volatilized, at such pre-exposure bake temperatures, so that an effective amount of the polar compound is present to complex with acid generated during imaging.
The preferred method for formation of the copolymer comprises hydrogenation of a preformed novolak resin or a preformed poly(vinylphenol) resin. Hydrogenation may be carried out using art recognized hydrogenation procedures, for example, by passing a solution of the phenolic resin over a reducing catalyst such as a platinum or palladium coated carbon substrate or preferably over Raney nickel at elevated temperature and pressure. The specific conditions are dependent upon the polymer to be hydrogenated. More particularly, the polymer is dissolved in a suitable solvent such as ethyl alcohol or acetic acid, and then the solution is contacted with a finely divided Raney nickel catalyst and allowed to react at a temperature of from about 100 to 300° C. at a pressure of from about 50 to 300 atmospheres or more. The finely divided nickel catalyst may be a nickel-on-silica, nickel-on-alumina, or nickel-on-carbon catalyst depending upon the resin to be hydrogenated. Hydrogenation is believed to reduce the double bonds in some of the phenolic units resulting in a random copolymer of phenolic and cyclic alcohol units randomly interspersed in the polymer in percentages dependent upon the reaction conditions used.
In the negative resist systems, amine-based crosslinkers are preferred. Suitable amine-containing crosslinkers include urea-formaldehyde, melamineformaldehyde, benzoguanamine-formaldehyde, glycoluril-formaldehyde resins and combinations thereof. Other suitable amine-based crosslinkers include the melamines manufactured by American Cyanamid Company such as Cymel® 300, 301, 303, 350, 370, 380, 1116 and 1130; benzoguanamine resins such as Cymel® 1123 and 1125; glycoluril resins Cymel® 1170, 1171, 1172; and urea-based resins Beetle® 60, 65 and 80. A large number of similar amine-based compounds are presently commercially available from various suppliers. As known to those in the art, polymeric amine-based resins may be prepared by the reaction of acrylamide or methacrylamide copolymers with formaldehyde in an alcohol-containing solution, or alternatively by the copolymerization of N-alkoxymethyl acrylamide or methacrylamide with other suitable monomers.
1,1-bis[p-methoxyphenyl]-2,2,2-trichloroethane (methoxychlor®); 1,2,5,6,9,10-hexabromocyclododecane;
4,4'-dichloro-2-(trichloromethyl)benzhydrol or 1,-bis(chlorophenyl)-2-2,2-trichloroethanol (Kelthane®);
O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl)phosphorothioate (Dursban®);
The compositions of the invention are generally prepared following prior art procedures for the preparation of photoresists and other photocurable compositions. For a liquid coating composition, the solids portion of the composition is conventionally dissolved in a solvent. The solvent used does not constitute a part of the invention. However, for purposes of exemplification, useful solvents include glycol ethers, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, methoxy benzene and the like; Cellosolve® esters such as methyl Cellosolve acetate, ethyl Cellosolve acetate and propylene glycol monomethyl ether acetate; aromatic hydrocarbons such as toluene, xylene and the like; ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone; esters such as ethyl acetate, butyl acetate, hexyl acetate, isobutyl isobutyrate and butyl lactone; amides such as dimethylacetamide, N-methyl pyrrolidione and dimethyl formamide; chlorinated hydrocarbons such as methylene chloride, ethylene dichloride, 1,1,1-trichloroethane, chlorobenzene and ortho-dichlorobenzene; nitrobenzene; dimethyl sulfoxide; alcohols such as diacetone alcohol; and mixtures of the foregoing.
For typical photoresist applications, following coating of a composition of the invention onto a surface, it is subjected to a pre-exposure soft bake, i.e. heated to about 90° C. to remove the solvent until preferably the resist coating is tack free. Thereafter, it is imaged through a mask in conventional manner. The exposure is sufficient to effectively activate the photoactive component of the resist system to produce a patterned image in the resist coating layer and, more specifically, the exposure energy typically ranges from about 10 to 300 mJ/cm2, dependent upon the exposure tool. The wavelength of activating radiation will, of course, vary with the photoactive components of a given radiation sensitive composition and will be known to those skilled in the art. The spectral response of a radiation sensitive composition can be expanded by the use of suitable radiation sensitizer compounds.
Following exposure, the composition is preferably baked at temperatures ranging from about 50° C. to about 140° C. to release an activating amount of acid from the complex of the polar compound and the photogenerated acid, and effect the acid-catalyzed reaction. Preferably the activating amount of acid released from the polar compound-photogenerated acid complex during post exposure bake is sufficient to catalyze a reaction that results in a solubility differential of preferably at least about 10:1, more preferably at least about 100:1, between exposed and unexposed regions of a coating layer of the radiation sensitive composition. Thereafter, the film is developed, preferably with an aqueous based developer such as an inorganic alkali exemplified by sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, sodium silicate, sodium metasilicate, aqueous ammonia or the like. Alternatively, organic developers can be used such as choline based solutions; quaternary ammonium hydroxide solutions such as a tetra-alkyl ammonium hydroxide solution; various amine solutions such as ethyl amine, n-propyl amine, diethyl amine, di-n-propyl amine, triethyl amine or methyldiethyl amine; alcohol amines such as diethanol amine or triethanol amine; cyclic amines such as pyrrole, piperidine, etc. In general, development is in accordance with art recognized procedures.
Following development, a bake at temperatures of from about 100° C. to about 250° C. for several minutes may be employed if desired.
A photoresist composition was prepared consisting of 10 g of poly(p-vinyl)phenol (hereafter "PVP") at a 10% level of hydrogenation, 2 g of t-butyloxycarbonato-bis-phenol-A and 1.5 g of tris(1,2,3-methane-sulfonyl) benzene dissolved in 27.5 g of diethylene glycol dimethyl ether. This resist formulation was coated to 1.0 micron thickness on three separate silicon wafers (hereafter "the first wafer", "second wafer" and "third wafer") using a conventional spin coater. The wafers were each soft baked at 90° C. for 1 minute, and then exposed for 10 seconds on an HTG deep UV exposure unit with a variable optical density mask placed between the source and the wafer. The first wafer was subjected to a time delay between exposure and post exposure bake of 5 minutes; the second wafer was subjected to a time delay of 120 minutes; and the third wafer was subjected to a time delay of 24 hours between exposure and post exposure bake. All three wafers were post exposure baked at 120° C. for 1 minute. The three wafers were then batch developed in MF-321 (tetramethylammonium hydroxide sold by Shipley Company of Newton, Mass.) for 60 seconds. For the first and second wafers with delay times of 5 and 60 minutes, respectively, the contrast curves overlapped. For the third wafer stored for 24 hours, it was observed that the resist slowed down as a function of the delay between exposure and post exposure bake. Further, in the case of the third wafer, the photoresist became, for practical purposes, insoluble in the developer. While not wishing to be bound by theory, it is believed this result indicates slow diffusion of acid in the unexposed areas leading to lower concentration of acid in the exposed areas during the bake step and thereby decreasing the number of blocked sites deprotected in the exposed areas.
A photoresist composition was prepared by mixing 10 g of PVP at 10% hydrogenation, 0.75 g of purified hexamethoxymethylmelamine, and 0.5 g tris(trichloromethyl)triazine dissolved in 28.25 g diethylene glycol dimethyl ether. The resist was coated to 1.0 micron thickness on three separate silicon wafers using a conventional spin coater. The wafers were then baked at 90° C. for 1 minute, and then exposed on a GCA ALS Laserstep 5:1 excimer laser stepper. The first wafer was subjected to a time delay between exposure and post exposure bake of 5 minutes; the second wafer was subjected to a time delay of 120 minutes; and the third wafer was subjected to a time delay of 24 hours. All three wafers were post exposure baked at 130° C. for 1 minute. The wafers were batch developed in 0.135 N MF-312 (tetramethyl ammonium hydroxide) for 150 seconds. As a measure of diffusion, the changes in linewidth of a 0.5 micron feature were observed during the time delay between exposure and post exposure bake. The line width change increased with increasing time delay between exposure and post exposure bake. For the wafer subjected to the 24 hour time delay, the 0.5 micron linewidth was reduced to 0.2 micron. While again not wishing to be bound by theory, it is believed this loss of linewidth resulted from diffusion of acid into the unexposed regions of the resist coating layer, leading to less acid in the exposed areas and hence linewidth shrinkage as if the resist layer had been underexposed.
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and methodsUS20060051706 *Oct 12, 2005Mar 9, 2006Shipley Company, L.L.C.Radiation sensitive compositions and methodsUS20060183218 *Jun 4, 2004Aug 17, 2006Kiyohisa TakahashiMaterial for forming fine pattern and method for forming fine pattern using the sameUS20070287087 *May 24, 2007Dec 13, 2007Yoshiko MiyaColored photosensitive resin composition, color filter, image sensor, and camera systemUS20080241764 *Sep 5, 2006Oct 2, 2008Nxp B.V.Lithographic MethodUS20090130611 *Sep 5, 2006May 21, 2009Nxp B.V.Lithographic MethodUS20110097667 *Oct 25, 2010Apr 28, 2011Tokyo Ohka Kogyo Co., Ltd.Positive resist composition, method of forming resist pattern, and polymeric compoundUS20110117491 *Aug 23, 2010May 19, 2011Tokyo Ohka Kogyo Co., Ltd.Resist composition and method of forming resist patternUS20110165512 *Nov 5, 2010Jul 7, 2011Tokyo Ohka Kogyo Co., Ltd.Resist composition and method of forming resist patternEP1860503A2 *May 24, 2007Nov 28, 2007Sumitomo Chemical Company, LimitedColored photosensitive resin composition, color filter, image sensor, and camera systemEP1860503A3 *May 24, 2007Oct 1, 2008Sumitomo Chemical Company, LimitedColored photosensitive resin composition, color filter, image sensor, and camera systemWO2007029177A1 *Sep 5, 2006Mar 15, 2007Nxp B.V.Lithographic method* Cited by examinerClassifications U.S. Classification430/326, 430/270.1, 430/327, 430/325, 430/330International ClassificationG03F7/004, G03F7/38, G03F7/032, G03F7/028, G03F7/038, G03F7/40, G03F7/039, G03F7/022, G03F7/30Cooperative ClassificationG03F7/0382, G03F7/038, G03F7/0045, G03F7/004, G03F7/40, G03F7/039, G03F7/0226, G03F7/0392European ClassificationG03F7/038C, G03F7/004D, G03F7/038, G03F7/004, G03F7/40, G03F7/022M, G03F7/039Legal EventsDateCodeEventDescriptionApr 18, 2003FPAYFee paymentYear of fee payment: 4Apr 19, 2007FPAYFee paymentYear of fee payment: 8Mar 24, 2011FPAYFee paymentYear of fee payment: 12RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy 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