Claims
- 1. The method of making a substituted polymeric material for use in resist compositions, comprising the steps of:
- (a) dissolving a polymer having acid labile groups pendent to the polymer backbone thereof in an acid stable solvent,
- (b) heating the solution with stirring under an unreactive atmosphere to a temperature in the range 20 to 70.degree. C.,
- (c) adding concentrated mineral acid to the stirred solution in an amount sufficient to remove acid labile groups from the polymer,
- (d) continuing the reaction until the desired degree of substitution is achieved,
- (e) quenching the reaction with base, and
- (f) precipitating the substituted polymeric material.
- 2. The method of claim 1 wherein the polymer is polystyrene.
- 3. The method of claim 1 wherein the acid labile groups are selected from the group consisting of alkyloxycarbonyl, aryloxycarbonyloxy and alkyloxycarbonyloxy.
- 4. The method of claim 3 wherein the alkyl portion of the acid labile group has an available hydrogen on an a carbon atom.
- 5. The method of claim 4 wherein the alkyl portion of the acid labile group is secondary alkyl or tertiary alkyl.
- 6. The method of claim 5 wherein the acid labile group is t-butyloxycarbonyloxy.
- 7. The method fo claim 1 wherein the pKa of the acid is less than about 4.
- 8. The method of claim 7 wherein the mineral acid is sulfuric acid.
- 9. The method of claim 1 wherein the reaction temperature is in the range of 50-60.degree. C.
- 10. The method of claim 1 wherein the reaction is quenched with ammonium hydroxide.
- 11. The method of claim 1 wherein the substituted polymeric material is precipitated in ammonium acetate.
Parent Case Info
This application is a Continuation of Application Ser. No. 07/933,432, Aug. 8, 1992, now abandoned.
US Referenced Citations (8)
Non-Patent Literature Citations (1)
Entry |
H, Ito, "Solid-State Thermolysis of Poly(p-t-Butoxycarbonyloxystyrene) Catalyzed by Polymeric Phenol: Effect of Phase Separation", Journal of Polymer Science: Part A, vol. 24, p. 2971-2980, (1986). |
Continuations (1)
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Number |
Date |
Country |
Parent |
933432 |
Aug 1992 |
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