JP2002514664A - Method for producing a purified solution of a blocked polyhydroxystyrene resin - Google Patents

Abstract

  (57) [Summary] (1) a step of forming an impure reaction solution containing a blocked polyhydroxystyrene resin and an acidic catalyst in a reaction solvent; and (2) an amine, water, at least one hydrocarbon solvent, and at least one photoresist solvent. To form an aqueous phase comprising water and an amine / at least one salt of said acidic catalyst, and an organic phase comprising said reaction solvent, said hydrocarbon solvent, said photoresist solvent and said blocking polyhydroxystyrene resin. And (3) separating the aqueous phase from the organic phase; and (4) removing the hydrocarbon solvent and the reaction solvent from the organic phase, thus removing the barrier polyhydroxystyrene in the photoresist solvent. Forming a purified solution of the resin, the method comprising the steps of:

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of making a barrier polyhydroxystyrene resin or barrier cross-linked polyhydroxystyrene resin that is useful in chemically amplified photoresist formulations.

BRIEF DESCRIPTION OF THE TECHNOLOGY Polyhydroxystyrene resins, in which some or all of the hydroxy groups in the resin are converted to acid-labile protecting groups ("blocking groups"), are chemically amplified photoresists. It is generally used as a polymer material inside. These chemically amplified photoresists have been used in advanced photolithographic processes in semiconductor manufacturing.

[0003] Cross-linked polyhydroxystyrene resins (blocking cross-linked polymers) in which some or all of the hydroxy groups have been converted to acid-labile protecting groups and the cross-linking moiety has also been treated are well known. For example, European Patent Application Publication No. 07183, issued June 26, 1996
See No. 16A2 and No. 0738744A2, issued Oct. 23, 1997. Both of these European Patent Application publications are incorporated herein by reference in their entirety.
These barrier cross-linking resins have been used as polymeric materials in chemically amplified photoresists instead of or in conjunction with barrier resins.

[0004] In the preparation of these barrier resins or these barrier cross-linked polyhydroxystyrene resins, the precursors (eg, polyhydroxystyrene, protecting group precursors and, optionally, a cross-linking agent) require the presence of acidic catalysts and suitable organic reaction solvents The combined reaction was carried out below to form an impure solution of the barrier polymer or barrier cross-linked polymer in the reaction solvent. After the reaction was completed, the reaction mixture was then passed through a layer of a strongly basic ion exchange resin to remove the acidic catalyst. The treated reaction solution was then mixed with deionized water or a mixture of deionized water and an alcohol (eg, ethanol or isopropanol) to precipitate the barrier resin or barrier cross-linking resin in the form of a solid. Thereafter, the precipitated solid resin was separated from the reaction mixture, preferably by filtration or centrifugation. Next, the separated resin was washed with another deionized water, and then dried under vacuum. The dried solid barrier resin or barrier cross-linking resin was later dissolved in a suitable organic photoresist solvent and then used to produce chemically amplified photoresist formulations.

[0005] This prior art method of making these barrier resins and barrier cross-linking resins has several disadvantages associated with the method. Its disadvantages include:

(1) The resin layer used to remove the acidic catalyst needs to have a very small metal content. This requirement is to use high-purity and expensive ion exchange resin,
Alternatively, it can only be satisfied by using a special cleanup procedure for the standard ion exchange resin after each run. In addition, the ion exchange resin layer must be very dry when passing the reaction mixture through it (ie, contains no water in the layer). Otherwise, water (in the presence of a catalyst or ion exchange resin) can hydrolyze the blocking polymer. Still further, in some cases, the ion exchange resin may act as a catalyst for undesired reactions or may retain some of the barrier or barrier cross-linking polymers. And in any case, the use of ion exchange resins also requires cleanup and disposal. (2) The phase change precipitation step requires a large amount of water (ie, at least 20 times the weight of the reaction mixture). The use of less water results in sticky solids that adhere to the sides of the settling tank. Large amounts of water cause large amounts of wastewater to be treated. Large and expensive sedimentation tanks must also be used. (3) The separation step requires special and expensive filtration and centrifugation equipment. Handling of these solids during and after this separation step is a potential source of contamination since it is almost impossible to keep these solids separated from the environment. (4) Drying of the solids is another potential source of contamination both from the dryer equipment itself and the handling required for unloading and unloading the dryer. Drying causes undesirable side reactions in the product.

[0007] Accordingly, there is a need for an improved method for producing a pure barrier resin or a pure barrier cross-linked resin without the above-mentioned disadvantages of the prior art. The present invention provides such a method. In particular, the method of the present invention reduces waste generation, reduces the potential for product contamination, and eliminates the handling of solids. This method allows the purified resin to be directly dissolved in the photoresist solvent, rather than solidifying the purified resin and then redissolving it in the photoresist solvent.

BRIEF SUMMARY OF THE INVENTION [0008] One embodiment of the present invention comprises: (1) forming an impure reaction solution comprising a blocked polyhydroxystyrene resin and an acidic catalyst in a reaction solvent; Adding water, at least one hydrocarbon solvent, and at least one photoresist solvent, and thus an aqueous phase comprising water and an amine / at least one salt of the acidic catalyst, and the reaction solvent, the photoresist solvent, Forming an organic phase containing a hydrocarbon solvent and the blocking polyhydroxystyrene resin; (3) separating the aqueous phase from the organic phase; and (4) combining the hydrocarbon solvent and the reaction solvent with the organic phase. Removing from the phase, thus forming a purified solution of the blocking polyhydroxystyrene resin in the photoresist solvent. It relates to a method for producing a purified solution of blocking polyhydroxystyrene resins bets solvent.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As used herein and in the claims, the term "reaction solvent" is used to refer to any single unit in which either a blocked polyhydroxystyrene resin or a blocked crosslinked polyhydroxystyrene resin is prepared. It means one solvent or a mixed solvent. A preferred reaction solvent is tetrahydrofuran (THF). This solvent is a good solvent for the reactants and products, is not reactive, is hydrophilic, has a low specific gravity (so that the resulting organic phase has a lower specific gravity than water) It is preferred because it has a very low boiling point (so that it would be easy to separate this solvent from PGMEA or other selected photoresist solvents that have a higher boiling point). Another suitable reaction solvent is 1,4-dioxane.

As used herein, the term “photoresist solvent” refers to a solvent or mixture of solvents in which a radiation-sensitive composition, such as a photoresist, is made. Generally, such radiation-sensitive compositions of the present invention comprise a purified blocked polyhydroxystyrene resin, or a purified blocked crosslinked polyhydroxystyrene resin, and at least one photoacid generator and optionally other resins and dissolution inhibitors. And other components. A "photoresist solvent" as referred to herein is different from a "reaction solvent" referred to herein.

As used herein, the term “blocked polyhydroxystyrene resin” refers to the conversion of some or all of the hydroxy groups in the resin to protecting groups (eg, vinyl ether groups) as well as chemically amplified. Any and all polyhydroxystyrene resins that are useful in the type of photoresist indicated are meant. As used herein, the term "blocked polyhydroxystyrene resin" refers to "
Resins of the class "blocked crosslinked polyhydroxystyrene resins".

The term “blocked cross-linked polyhydroxystyrene resin” as used herein and in the claims means that some or all of the hydroxy groups in the resin have been converted to protecting groups (eg, vinyl ether groups). It includes any and all polyhydroxystyrene resins that include crosslinkable moieties that link the polymer chains and that are useful in chemically amplified types of photoresist.

[0013] As used herein and in the claims, the phrase "impure solution of a blocked polyhydroxystyrene resin in a reaction solvent" refers to all of the compounds containing the blocked polyhydroxystyrene resin in a single reaction solvent or mixture of reaction solvents. And any solution is meant and further contains unacceptable amounts of impurities and / or reaction by-products and / or unreacted reaction precursors.

As used herein and in the claims, the phrase “purified solution of a blocked polyhydroxystyrene resin in a photoresist solvent” is used to refer to any and all of the resins that contain the blocked polyhydroxystyrene resin in the photoresist solvent or mixture of solvents. Purified solutions can be used in chemically amplified types of photoresists, since any solution implies further containing an acceptably small amount of impurities.

[0015] The first step of the present invention is aimed at forming an impure reaction solution containing a blocking polyhydroxystyrene resin and an acidic catalyst in one or more reaction solvents.

The impure reaction solution is preferably placed in a reactor containing a reaction solvent, preferably at least one polyhydroxystyrene resin, at least one protecting group precursor, an acidic catalyst,
And optionally adding the required amount of at least one cross-linking agent, and then reacting the reaction mixture for a sufficient time to form a blocked polyhydroxystyrene resin or a cross-linked blocked polyhydroxystyrene resin in the reaction mixture. Manufactured by heating to temperature.

[0017] Polyhydroxystyrene resins useful for this method include any polymeric resin containing hydroxystyrene repeat units, including poly (4-hydroxystyrene) homopolymer, poly (4-hydroxy-a -Methylstyrene) homopolymer and poly (3-hydroxystyrene) homopolymer, or a hydroxystyrene-containing monomer (eg, 4-hydroxystyrene), and acrylic acid, methacrylic acid, alkyl methacrylate, alkyl acrylate, styrene,
Copolymers formed from other monomers such as fumaronitrile, vinylcyclohexanol, maleic anhydride, maleimide and derivatives thereof, or mixtures of such homopolymers or copolymers. Preferred polyhydroxystyrene resin precursors include European Patent Applications 718316 and 73
No. 8744.

The protecting group precursor added to the reaction mixture is any such compound capable of forming an acid-labile protecting or blocking group on a hydroxy group in the side chain of the polyhydroxystyrene resin. These preferably include vinyl ethers (e.g.,
t-butyl vinyl ether or ethyl vinyl ether), carbonate (eg, t-butyl carbonate), or silyl ether, cumyl ether, tetrahydropyranyl ether, tetrahydropyranyl ester, enol ether, enol ester, t-alkyl ether, t-alkyl ester, Other precursors of suitable acid-labile protecting groups are included, including t-alkyl carbonate, acetal and ketal groups.

The one or more cross-linking agents can include any suitable chemical that cross-links the polyhydroxystyrene in a manner necessary to achieve a resin suitable for photoresist applications. One preferred crosslinker is 4,4'-isopropylidenedicyclohexanol.

This reaction is performed in the presence of an acidic catalyst. Examples of suitable acidic catalysts include acidic ion exchange resins or acids such as sulfonic acids (preferably toluenesulfonic acid) or salts of sulfonic acids, for example, pyridinium tosylate.

[0021] The reaction is also carried out in the presence of a suitable reaction solvent.

The reaction is generally carried out at a reaction temperature of about 10 ° C. to about 80 ° C. for a time sufficient to effect sufficient conversion of the hydroxyl groups to protecting groups and crosslinking of any resin. The reaction is generally performed in any standard reactor apparatus, preferably a glass reactor or a Teflon coated reactor to prevent the build up of cationic and anionic impurities in the reaction mixture.

The relative percentage of resin precursor added to the reactor depends on the final desired properties of the resin. Generally, the resulting blocked polyhydroxystyrene resin or blocked crosslinked polyhydroxystyrene resin is preferably between 1,000 and 1,000,000.
000, more preferably about 3,000 to about 500,000, and most preferably about 6
It has a weight average molecular weight of from 000 to about 100,000. The percentage of hydroxyl groups in the polyhydroxystyrene resin precursor that is converted to acid-labile protecting groups is
Generally about 5% to about 95%, more preferably about 10% to 50%. Degree of crosslinking (v
= O / m + n + o) is preferably 0.001 to 0.5, more preferably 0.0
Where m is the average number of acid cleavable protecting groups per molecule of the resulting resin, and n is the sum of COOH groups and phenolic hydroxyls per resin obtained. And o is the number of bridging groups per resin obtained.

After the reaction is completed, at least one photoresist solvent and at least one hydrocarbon solvent are added to the reaction mixture in addition to water and the amine compound. Their addition causes the formation of an organic phase and an aqueous phase in the resulting mixture.

[0025] The photoresist solvent is preferably propylene glycol monomethyl ether acetate (PGMEA). Other conventional photoresist solvents can also be used.

The hydrocarbon solvent is preferably hexane, and the hydrocarbon solvent is used because of its hydrophobicity and its ability to dissolve impurities in the organic phase. Generally, the amount of photoresist solvent and hydrocarbon solvent is about 1:20 to 20: 1 by weight.

It is particularly preferred to use hexane as the hydrocarbon solvent. This solvent has minimal water solubility, can promote the solubility of the barrier resin, has a low specific gravity (so that the resulting organic phase has a lower specific gravity than water), and has propylene glycol monomethyl ether acetate ( Because it has a lower boiling point than conventional photoresist solvents such as PGMEA). In all, the solvent is PGM
It has been found that when EA is the photoresist solvent, it provides good separation of the organic and aqueous phases.

The relative amount of water is preferably from about 1:10 to about 10: 1 of the total amount of organic solvent.

[0029] The amount of amine is preferably sufficient to neutralize the amount of acidic catalyst present. Any conventional amine useful for this purpose can be used. Triethylamine is particularly preferred.

Next, the obtained organic phase is separated from the aqueous phase. This is generally performed by simple phase separation. The bottom aqueous phase is usually withdrawn from the reactor, leaving the organic phase in the reactor.

Preferably, after this phase separation, an additional water wash is optionally performed. This involves adding an amount of water to the reactor, so that the reaction mixture can settle, after which the added water is removed. Generally, it is preferable to perform at least one water washing operation.

[0032] After the phase separation step and after any optional water washing, the hydrocarbon solvent is removed from the reaction mixture. Preferably, this is performed by simple distillation to distill off the hydrocarbon solvent, leaving a final purified solution consisting of the photoresist solvent and the barrier polyhydroxystyrene resin or barrier crosslinked polyhydroxystyrene resin.

The photoresist composition may comprise at least one photoacid generator, at least one other dissolution inhibitor, such as any dissolution inhibitor, and, if necessary, more photoresist solvent and / or other photoresist. It can be produced by simply adding a resist solvent to this purified solution.

The following examples and comparative examples are shown in order to better explain the present invention. Unless indicated otherwise, all parts and percentages are by weight and all temperatures are in degrees Celsius.

Example 1 A. Synthesis of Blocked Crosslinked Polyhydroxystyrene Resin 380 grams of dry polyhydroxystyrene (PHS) (weight average molecular weight (M
W) = 8700), 7.8 grams of 4,4'-isopropylidenedicyclohexanol (IPDCH) and 1592.7 grams of tetrahydrofuran (THF
) Was added to a 2 liter plastic bottle. The jar was rolled for 2 days to dissolve the solids. The solution was transferred to a 5 liter kettle. 100.2 grams of t-butyl vinyl ether (TBVE) (0.315 mole per mole of PHS) and 26.75 grams of a 0.1% by weight solution of p-toluenesulfonic acid catalyst (PTSA) in THF were added to the kettle. . The materials in the kettle were mixed at 25 ° C. overnight. The next morning, the contents of the kettle were split into two parts and further processed as described below.

B. Treatment of Blocked Crosslinked Polyhydroxystyrene by Extraction 1.47 grams of a 1.0% by weight solution of triethylamine (TEA) in THF was added to the first portion of the material in the kettle synthesized in (A) above (1662.98). G). 1256.13 grams of propylene glycol monomethyl ether acetate (PGMEA) and 451.12 grams of hexane were also added. After mixing the solution in the kettle, 585.74 grams of deionized water (DI) was added to the kettle (first wash). The materials in the kettle were mixed for 5 minutes, the stirrer was stopped, and the materials were allowed to settle into two phases, a first aqueous phase and a first organic phase. The aqueous phase is composed of water and a small amount of triethylamine / p-toluenesulfonate,
And contained residual vinyl ether, water-soluble by-products, THF, small amounts of PGMEA and trace metals. The organic phase contained most of the PGMEA, THF, hexane, and some water in addition to the blocked cross-linked polystyrene. After holding for 90 minutes, 582.18 grams of the first aqueous phase was removed from the bottom of the kettle and another 586 of DI water
. 31 grams were added to the kettle (second wash). The materials in the kettle were mixed for 5 minutes, the stirrer was turned off and the materials were allowed to settle. After holding for 80 minutes, 755
. 8 grams of the second aqueous layer was removed from the bottom of the kettle and 586.54 grams of another DI water was added to the kettle (third wash). Mix the ingredients in the kettle for 5 minutes,
The stirrer was stopped and the material was allowed to settle. After a 75 minute hold, 751.08 grams of the third aqueous layer was removed from the bottom of the kettle. The organic layer remaining in the kettle was transferred to a rotary evaporator system where THF, hexane, residual water and some PGMEA were removed from the kettle.
Removed under vacuum at a bath temperature of ° C. The mixture was stripped until the resulting solution contained 0.07 wt% water and 45.1 wt% total solids. 401.3 grams of PGMEA was added to 830.19 grams of the stripped solution, resulting in a solution containing about 30% solids by weight. The solids yield was about 99% based on the solids in solution and assuming that all of the PHS and 85% of the IPDCH and 85% of the vinyl ether should eventually be in the solids. Was.

Comparative Example 1 A second portion (443.24 grams) of the blocked crosslinked polyhydroxystyrene material synthesized in (A) above was placed in an addition funnel. 1. Pyridine in THF.
0.42 grams of a 0% by weight solution was added to the funnel and shaken to mix in the pyridine solution. The mixture is equilibrated with THF with AMBERSEP900 (OH)
The solution was passed through a column of strongly basic ion exchange resin and added to 8750 grams of DI water in a 10 liter resin kettle. The addition time was about 60 minutes. After the addition was completed, the addition funnel and resin layer were rinsed with 20 ml of THF, which was also added to DI water. The precipitated solid was recovered from the DI water by vacuum filtration in a Buchner filter. The collected solid was washed twice with 500 ml of DI water and dried in a vacuum dryer at 50 ° C. for about 20 hours. Solid polymer 90 having a water content of 1.08% by weight
. Six grams were collected. The solids yield was about 91%.

The solid polymers and polymer solutions from Example 1 and Comparative Example 1 were analyzed by GPC for molecular weight distribution and by ¹³ CNMR for blocking levels, and the two polymers were identical within the accuracy of the test.

Comparative Example 2 Some amount of TBVE (0 per mole of PHS
. Another experiment was performed in the same manner as in Example 1, except that 36 mol) was used.
However, the two polymers were completely different. The polymer in solution had the expected level of blocking and molecular weight distribution. The solid polymer had very low blocking levels and low molecular weight. Apparently, the solid polymer became contaminated and unblocked during solids recovery or drying.

Example 2 About 650 grams of PHS was dried in a vacuum oven overnight to yield a moisture content of 0.65% by weight. 299.6 grams of dry PHS, 12.24 grams of IPDC
H and 1320.05 grams of THF were added to a 4 liter resin kettle.
The mixture was stirred for 80 minutes until the solids dissolved.

68.41 grams of ethyl vinyl ether and 0.1 of PTSA in THF
90.0 grams of the weight percent solution was added to the resin kettle. The mixture was stirred overnight at room temperature. After mixing overnight, 5.83 grams of a 1.0% by weight solution of triethylamine in THF was added to the reaction mixture to neutralize the PTSA catalyst.

1320.2 grams of PGMEA, 311.98 grams of hexane and 31
1.98 grams of DI water was added to the kettle (first wash). The resulting mixture was stirred for 8 minutes, stirring was stopped and the mixture was allowed to settle for about 1 hour. 183.86 grams of the first aqueous layer was removed from the bottom of the kettle and 312.94 grams of DI water was added to the kettle (second wash). The materials in the kettle were mixed for 15 minutes, the stirrer was stopped, and the materials were allowed to settle for about 1 hour. A second aqueous layer of 420.89 grams was removed from the bottom of the kettle and 311.98 grams of DI water was added to the kettle (third wash). The materials in the kettle were mixed for about 15 minutes, the stirrer was stopped, and the materials were allowed to settle for about 1 hour. Third water layer 43
8.32 grams were removed from the bottom of the kettle.

The organic layer remaining in the kettle in the third wash was transferred to a rotary evaporator system where THF, hexane, residual water and some PGMEA were removed under vacuum at a bath temperature of 55 ° C. The resulting solution was 0.06% by weight water and 39.9% by weight total solids
The mixture was stripped until it contained. PG in stripped solution
Addition of the MEA resulted in a solution containing about 30% solids by weight. The solids yield was about 99%. The resin in the product was analyzed by GPC, _{M W} is 32,
_Xrel was 2.22 [relative cross-linking (X _rel ) equals (total molecular weight of the resin divided by the molecular weight of the non-cross-linked portion of the resin) minus one].

Although the present invention has been described above with reference to specific embodiments thereof, it is evident that many changes, modifications and variations may be made without departing from the inventive concept disclosed herein. It is. It is therefore intended to cover all such changes, modifications and variations that fall within the spirit and scope of the appended claims. All patent applications, patents, and other publications mentioned herein are incorporated by reference in their entirety.

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Claims (13)

[Claims] 1. A step of (1) forming an impure reaction solution containing a blocked polyhydroxystyrene resin and an acidic catalyst in a reaction solvent; and (2) an amine, water, at least one kind of hydrocarbon solvent, and at least one kind. And thus an aqueous phase comprising water and an amine / at least one salt of said acidic catalyst, and comprising said reaction solvent, said hydrocarbon solvent, said photoresist solvent and said blocking polyhydroxystyrene resin Forming an organic phase; (3) separating the aqueous phase from the organic phase; and (4) removing the hydrocarbon solvent and the reaction solvent from the organic phase, thereby removing the organic solvent from the organic solvent. Forming a purified solution of the blocked polyhydroxystyrene resin, comprising the steps of: . 2. The method according to claim 1, wherein the blocking group of the blocking polyhydroxystyrene resin is t-butyl vinyl ether. 3. The method according to claim 1, wherein the removing step includes simple distillation. 4. The method according to claim 1, wherein the reaction solvent is tetrahydrofuran. 5. The method according to claim 1, wherein the acidic catalyst is toluenesulfonic acid. 6. The method according to claim 1, wherein the amine is triethylamine. 7. The method according to claim 1, wherein the hydrocarbon solvent is hexane. 8. The method according to claim 1, wherein the photoresist solvent is propylene glycol monomethyl ether acetate (PGMEA). 9. The method according to claim 1, wherein after the step (3) and before the step (4), the separated organic phase is subjected to at least one washing operation with water. 10. The method according to claim 1, wherein the blocking polyhydroxystyrene resin is a blocking crosslinked polyhydroxystyrene resin. 11. The method of claim 10, wherein said blocking cross-linked resin is formed using ethyl vinyl ether as a protecting group precursor, and isopropylidene dicyclohexanol is a cross-linking agent. 12. A chemically amplified photoresist formulation comprising adding at least one photoacid generator to a purified solution of a blocked polyhydroxystyrene resin produced by the production method of claim 1. How to manufacture. 13. A chemically amplified photoresist formulation, comprising adding at least one photoacid generator to a purified solution of a blocked cross-linked polyhydroxystyrene resin produced by the production method of claim 10. How to make things.