Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F12/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F12/02—Monomers containing only one unsaturated aliphatic radical
  • C08F12/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F12/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by hetero atoms or groups containing heteroatoms
  • C08F12/22—Oxygen
  • C08F12/24—Phenols or alcohols
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
  • C08J3/09—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F6/00—Post-polymerisation treatments
  • C08F6/02—Neutralisation of the polymerisation mass, e.g. killing the catalyst also removal of catalyst residues
• • 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
  • G03F7/039—Macromolecular compounds which are photodegradable, e.g. positive electron resists
• • 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
  • G03F7/26—Processing photosensitive materials; Apparatus therefor
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
  • C08J2325/18—Homopolymers or copolymers of aromatic monomers containing elements other than carbon and hydrogen

Definitions

• the present invention is directed to a process for producing blocked polyhydroxystyrene resins or blocked, crosslinked polyhydroxystyrene resins that are useful in chemical amplified photoresist formulations.
• Polyhydroxystyrene resins where some or all of the hydroxy groups in the resin are converted into acid-labile protecting groups are commonly used as polymeric materials in chemically amplified photoresists. These chemically amplified photoresists are employed in advanced photolithographic processes of semiconductor fabrication.
• Crosslinked polyhydroxystyrene resins having some or all of the hydroxy groups converted to acid-labile protecting groups and also possessing crosslinking moieties (“blocked, crosslinked polymers”) are also well known. See, for example, European Published Patent Application Nos. 0718316 A2, published on June 26, 1996, and 0738744 A2, published on October 23, 1997. Both of these published European Patent Applications are incorporated herein by reference in their entireties.
• blocked, crosslinked resins are employed instead of or in conjunction with blocked resins as the polymeric materials in chemical amplified photoresists.
• the precursors e.g., the polyhydroxystyrene, the protecting group precursor and, optionally, the crosslinking agent
• the reaction mixture was then passed through a bed of strong base ion exchange resin to remove the acid catalyst.
• the treated reaction solution was then combined with deionized water or a mixture of deionized water and an alcohol (e.g., ethanol or isopropanol) to precipitate the blocked resin or blocked, crosslinked resin in solid form.
• the precipitated solid resin was then separated from the reaction mixture, preferably by filtration or centrifugation.
• the separated resin was then washed with more deionized water and then vacuum dried.
• the dried, solid blocked resin or blocked, crosslinked resin was later dissolved in a suitable organic photoresist solvent and then used to make a chemical amplified photoresist formulation.
• This prior art method of making these blocked resins and blocked, crosslinked resins has several disadvantages associated with it, including: (1) The resin bed employed to remove the acid catalyst must have a very low trace metals content. This need can be met by only either using a high purity and expensive ion exchange resin or using a special cleanup procedure for standard ion exchange resins after each run. Furthermore, the ion exchange resin bed must be very dry (i.e., contain no water therein) when the reaction mixture is passed through it. Otherwise, the water (in the presence of the catalyst or ion exchange resin) may hydrolyze the blocked polymer.
• the ion exchange resin may act as a catalyst for unwanted reactions or may retain some of the blocked polymer or blocked, crosslinked polymer, thereby reducing the yield of the blocked polymers or blocked, crosslinked polymer. And, in any case, the employment of the ion exchange resin also requires cleanup and disposal.
• the phase change precipitation step requires a large amount of water (; ' .e., at least 20 times the weight of the reaction mixture). The use of smaller amounts of water will result in sticky solids that adhere to the sides of the precipitation vessel. The large amount of water results in a large quantity of wastewater that must be disposed of. Also, a large and costly precipitation vessel must be employed.
• the separation step requires special and costly filtration and centrifugation equipment. Handling these solids during and after this separation step is a potential source of contamination because it is almost impossible to keep these solids isolated from the environment.
• the drying of the solids is another potential source of contamination, both from the dryer equipment itself and the handling required to load and unload the dryer. Also, drying may cause unwanted side reactions in the product to occur. Accordingly, there is a need for an improved process for preparing pure blocked resins or pure blocked, crosslinked resins without the above disadvantages of the prior art.
• the present invention offers such a process.
• the process of the present invention reduces waste generation, reduces the probability of product contamination and eliminates solids handling. This process allows for the purified resin to be directly dissolved in the photoresist solvent rather than having this purified resin put in solid form and then redissolved in the photoresist solvent.
• One aspect of the present invention is directed to the process for preparing a purified solution of blocked polyhydroxystyrene resin in a photoresist solvent, comprising the steps of: (1) forming an impure reaction solution comprising blocked polyhydroxystyrene resin and acidic catalyst in reaction solvent; (2) adding amine, water, at least one hydrocarbon solvent, and at least one photoresist solvent, thereby forming an aqueous phase and an organic phase, said aqueous phase comprising water and salts of the amine/acidic catalyst and the organic phase comprising the reaction solvent, the photoresist solvent, the hydrocarbon solvent and the blocked polyhydroxystyrene resin;
• reaction solvent refers to any single solvent or mixture of solvents in which either the blocked polyhydroxy-styrene resin or blocked crosslinked polyhydroxystyrene resin is prepared.
• the preferred reaction solvent is tetrahydro-furan (THF). This solvent is preferred because it is a good solvent for reactants and products, is not reactive, is hydrophilic, has a low density (so that the resulting organic phase will have a density less than water), and has a relatively low boiling point (so it would be easy to separate from PGMEA or other selected photoresist solvents having higher boiling points).
• Another suitable reaction solvent is 1,4-dioxane.
• photoresist solvent refers to the solvent or mixtures of solvents in which a radiation-sensitive composition such as a photoresist is prepared.
• a radiation-sensitive composition such as a photoresist is prepared.
• such radiation- sensitive compositions of the present invention will contain the purified blocked polyhydroxystyrene resin or the purified blocked, crosslinked polyhydroxystyrene resin, as well as at least one photoacid generator and optionally other ingredients such as other resins and dissolution inhibitors and the like.
• the "photoresist solvent” as referred to herein is different from the “reaction solvent” referred to herein.
• blocked hydroxystyrene resin refers to any and all polyhydroxystyrene resins that have some or all of the hydroxy groups in the resin converted to protecting groups (e.g., vinyl ether groups) and are useful in chemically amplified-type photoresists.
• protected polyhydroxystyrene resins as used herein includes resins of the class “blocked, crosslinked polyhydroxy styrene resins”.
• blocked, crosslinked polyhydroxystyrene resins refers to any and all polyhydroxystyrene resins that have some or all of the hydroxy groups in the resin converted to protecting groups (e.g., vinyl ether groups) and also contain crosslinking moieties linking separate polymeric chains and are useful in chemically amplified-type photoresists.
• impure solution of blocked polyhydroxystyrene resin in reaction solvent refers to any and all solutions containing blocked polyhydroxystyrene resins in a single reaction solvent or a mixture of reaction solvents and further contain unacceptable amounts of impurities and/or reaction by-products and/or unreacted reaction precursors.
• purified solution of blocked polyhydroxy-styrene resin in the photoresist solvent refers to any and all solutions containing blocked polyhydroxystyrene resins in photoresist solvent or mixture of solvents and further contains acceptably low amounts of impurities so that the purified solution may be used in chemically amplified-type photoresists.
• the first step of the present invention is directed to forming an impure reaction solution containing the blocked, polyhydroxystyrene resin and acidic catalyst in a reaction solvent or solvents.
• This impure reaction solution is preferably prepared by adding the desired amounts of at least one polyhydroxystyrene resin, at least one protecting group precursor, the acid catalyst and, optionally, at least one crosslinking agent to a reactor containing the reaction solvent and then heating this reaction mixture to a desired reaction temperature for a sufficient amount of time to produce the blocked polyhydroxy-styrene resin or the crosslinked, blocked polyhydroxystyrene resin in the reaction mixture.
• the polyhydroxystyrene resins useful for this process would include any polymeric resin that contains hydroxystyrene repeating units, including poly(4-hydroxystyrene) homopolymers, poly(4-hydroxy-a-methylstyrene)
• hydroxystyrene resin precursors include those disclosed in European Patent Application Nos. 718316 and 738744.
• the protecting group precursors added to this reaction mixture are any such compounds capable of forming an acid-labile protecting or blocking group on the hydroxy groups in the side chain of the polyhydroxystyrene resin.
• These preferably include vinyl ethers (e.g., tert.- butylvinyl ether or ethylvinyl ether), carbonates (e.g., tert.-butyl carbonate) or other precursors to suitable acid-labile protecting groups including silyl ether, cumyl ester, tetrahydropyranyl ester, tetrahydropyranyl ester, enol ether, enol ester, tert-.alkyl ether, tert.-alkyl ester, tert. alkyl carbonate, acetal and ketal groups.
• Mixtures of protecting group precursors may also be added to the reaction mixture.
• the optional crosslinking agent or agents may include any suitable chemical agent that crosslinks polyhydroxystyrene in a desirable way to achieve a suitable resin for a photoresist application.
• One preferred crosslinking agent is 4,4'-isopropylidene dicyclohexanol.
• acidic catalysts include acidic ionic exchanger resins or acids such as sulfonic acids (preferably, toluene sulfonic acid) or salts thereof, for example, pyridinium tosylate.
• the reaction is also carried out in the presence of a suitable reaction solvent.
• This reaction is generally carried out at reaction temperatures from about 10°C to about 80°C for a sufficient amount of time so that sufficient conversion of the hydroxyl groups to protecting groups and optional resin crosslinking occurs.
• the reaction is generally carried out in any standard
• the relative percentages of the resin precursors added to the reactor will depend upon the final desired characteristics of the resin.
• the resultant blocked polyhydroxy-styrene or blocked, crosslinked polyhydroxystyrene resins will preferably have a weight- average molecular weight of from 1 ,000 to 1 ,000,000; more preferably from about 3,000 to about 500,000 and most preferably from about 6,000 to about 100,000.
• the percentage of hydroxy groups in the polyhydroxystyrene resin precursor converted to acid-labile protecting groups will generally be from about 5% to about 95%, more preferably, from about 10% to 50%.
• At least one photoresist solvent and at least one hydrocarbon solvent are added to the reaction mixture, along with water and an amine compound. Their addition results in the formation of organic phase and aqueous phase in the resulting mixture.
• the photoresist solvent is preferably propylene glycol monomethyl ether acetate (PGMEA). Other conventional photoresist solvents may also be employed.
• the hydrocarbon solvent is preferably hexane and is employed because of its hydrophobic nature and its ability to dissolve impurities in the organic phase. Generally, the amounts of photoresist solvent and hydrocarbon solvent are about 1 :20 to 20:1 by weight.
• hexane as the hydrocarbon solvent is particularly preferred because this solvent has minimal water solubility; is capable of aiding the solubility of the blocked resin; has a low density (so that the resultant organic phase has a density less than water) and has a lower
• the relative amount of water is preferably about 1 : 10 to about 10:1 of the total amount of organic solvents.
• the amount of amine is preferably sufficient to neutralize the amount of acidic catalyst present. Any conventional amine useful for this purpose may be used. Triethylamine is particularly preferred.
• the resulting organic phase is separated from the aqueous phase. This is generally accomplished by simple phase separation. The bottom aqueous phase is normally drawn out of the reactor, leaving the organic phase in the reactor.
• additional water washes are optionally carried out. This encompasses adding an amount of water to the reactor, allowing the reaction mixture to settle and then removing the added water. Generally, it is preferred to conduct at least one water wash operation.
• the hydrocarbon solvent is removed from the reaction mixture.
• this is accomplished by simple distillation to distill off the hydrocarbon solvent and leave a final purified solution comprised of the photoresist solvent and the blocked polyhydroxystyrene resin or the blocked, crosslinked polyhydroxystyrene resin.
• a photoresist composition can be prepared by simply adding other photoresist components such as at least one photoacid generator, at least one optional dissolution inhibitor, and, if desired, more photoresist solvent and/or other photoresist solvents to this purified solution.
• PHS polyhydroxystyrene
• IPDCH 4,4' -isopropylidene dicyclohexanol
• THF tetrahydrofuran
• aqueous phase contained water with minor amounts of triethylamine/p-toluene sulfonic acid salt, as well as residual vinyl ether, water-soluble by-products, THF, a small amount of PGMEA and trace metals.
• the organic phase contained most of the PGMEA, THF, hexane, as well as some water besides the blocked, crosslinked polystyrene.
• COMPARISON EXAMPLE 1 The second portion of the blocked crosslinked polyhydroxystyrene material synthesized in (A) above (443.24 grams) was placed in an additional funnel. 0.42 grams of 1.0 wt. % solution of pyridine in THF was added to the funnel, and shaken to mix in the pyridine solution. This mixture was passed through a column of AMBERSEP 900 (OH) strong base ion exchange resin equilibrated with THF and into 8750 grams of Dl water in a 10 liter resin kettle. Addition time was about 60 minutes. After the addition was complete, the additional funnel and resin bed were rinsed with 20 ml of THF which was also added to the Dl water.
• Precipitated solids were recovered from the Dl water by vacuum filtration in a Buchner filter. Recovered solids were washed twice with 500 ml of Dl water and dried in a vacuum drier at 50°C for about 20 hours. 90.6 grams of solid polymer were recovered with a water content of 1.08 wt. %. Solids yield was about 91%.
• Example 10 The solid polymers and the polymer solutions from Example 1 and Comparison Example 1 were analyzed by GPC for molecular weight distribution and by 13 C NMR for blocking level within the accuracy of the tests, the two polymers were identical.

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• 1999
  • 1999-04-23 EP EP99917661A patent/EP1086147A4/en not_active Withdrawn
  • 1999-04-23 WO PCT/US1999/008875 patent/WO1999058579A1/en not_active Application Discontinuation
  • 1999-04-23 JP JP2000548381A patent/JP2002514664A/ja active Pending
  • 1999-04-23 KR KR1020007012410A patent/KR20010043388A/ko not_active Application Discontinuation
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