Nanocomposite photoresist composition for imaging thick films

1. A photoresist composition suitable for image-wise exposure and development comprising a positive photoresist composition and a nonfunctionalized inorganic particle material, the inorganic particle material being dispersed in propylene glycol mono-methyl ether prior to mixing with the positive photoresist composition, having an average particle size equal or greater than 10 nanometers, wherein the photoresist composition is capable of forming a photoresist coating film with a thickness greater than 5 microns.

2. The photoresist composition of claim 1 wherein the positive photoresist composition selected from

(1) a composition comprising (i) a film-forming resin having acid labile groups, and (ii) a photoacid generator, or

(2) a composition comprising (i) a film-forming novolak resin, and (ii) a photoactive compound, or

(3) a composition comprising (i) a film-forming resin, (ii) a photoacid generator, and (iii) a dissolution inhibitor.

3. The photoresist composition of claim 2 wherein the positive photoresist composition is (1) a composition comprising (i) a film-forming resin having acid labile groups, and (ii) a photoacid generator.

4. The photoresist composition of claim 2 wherein the positive photoresist composition is (2) a composition comprising (i) a film-forming novolak resin, and (ii) a photoactive compound.

5. The photoresist composition of claim 2 wherein the positive photoresist composition is (3) a composition comprising (i) a film-forming resin, (ii) a photoacid generator, and (iii) a dissolution inhibitor.

6. The photoresist composition according to claim 1 , where the film has a thickness greater than 10 microns.

7. The photoresist composition according to claim 1 , where the film has a thickness greater than 20 microns.

8. The photoresist composition according to claim 1 , where the film has a thickness less than 150 microns.

9. The photoresist composition according to claim 1 , where the inorganic particle material is colloidal silica.

10. The photoresist composition according to claim 1 , where the inorganic particle material has an average particle size from about 10 to about 50 nanometers.

11. The photoresist composition according to claim 1 , where the inorganic particle material has an average particle size from about 20 to about 50 nanometers.

12. The photoresist composition according to claim 1 , where the inorganic particle material is present in an amount of from about 0.1% and about 90% by weight of the photoresist.

13. The photoresist composition according to claim 1 , where the inorganic particle material is present in an amount of from about 5% and about 75% by weight of the photoresist.

14. The photoresist composition according to claim 1 , where the inorganic particle material is present in an amount of from about 10% and about 50% by weight of the photoresist.

15. The photoresist composition according to claim 1 , where the inorganic particle material is present in an amount of from about 10% and about 30% by weight of the photoresist.

16. The photoresist composition according to claim 4 , which further contains a nonionic surfactant.

17. The photoresist composition according to claim 16 , where the surfactant is a fluorinated and /or a silicone polymer.

18. The photoresist composition according to claim 4 , where the photoactive compound is a reaction product of a 2,1,5-, or 2,1,4-diazonaphthoquinone compound and a hydroxyl containing compound.

19. A process of forming a positive photoresist image on a substrate, comprising the steps of:

(a) coating the photoresist composition of claim 1 on a substrate, thereby forming a photoresist coating film with a thickness greater than 5 microns;

(b) image-wise exposing the coated substrate to actinic radiation; and

(c) developing the exposed substrate to form the photoresist image.