Resist composition

1. A resist composition consisting of (A) a hydrogen silsesquioxane resin having the formula

(HSi(OH)O 2/2 ) w (HSi(OR 1 )O 2/2 ) x (HSiO 3/2 ) y ((SiO 4/2 ) z ,

where R 1 is a linear or branched C 1 to C 6 alkyl or alkoxy group; w=0 to 1, x=0 to 1, y is >0 to 1,z is 0 to 1 and w+x+y+z≈1,

(B) an acid dissociable group-containing compound, (C) a photo-acid generator, (D) an organic solvent, and optionally (E) an additive.

2. The resist composition as claimed in claim 1 wherein the hydrogen silsesquioxane resin has a molecular weight of 1,000 to 50,000.

3. The resist composition as claimed in claim 1 wherein the acid dissociable groups in (B) have the formula

wherein each R 3 are independently a linking group;

R 4 a second linking group;

L is selected from the group consisting of linear or branch alkylene groups having 1 to 10 carbon atoms, fluoroalkylene groups having 2 to 20 carbon atoms, substituted and unsubstituted arylene groups, substituted and unsubstituted cycloalkylene groups, and substituted and unsubstituted alkarylene groups;

R 5 is hydrogen, linear or branched alkyl or fluoroalkyl;

R 6 is alkyl or fluoroalkyl;

Z is an acid-cleavable group; and

g may have a value of 0 or 1 and

h may have the value of 0 or 1; and

k may have the value of 0 or 1.

4. The resist composition as claimed in claim 3 wherein Z is selected from —OH, —COOH, esters of the formula —COOR 7 , carbonates of the formula —OCOOR 8 , ethers of the formula —OR 9 , wherein R 7 , R 8 and R 9 are selected to render Z acid-cleavable.

5. The resist composition as claimed in claim 3 wherein Z is an ester of the formula —COOR 7 and R 7 is a tertiary alkyl group.

6. The resist composition as claimed in claim 1 wherein (B) is poly(t-butylmethacrylate).

7. The resist composition as claimed in claim 1 wherein (B) is poly(t-butoxycarbonyl norbornyl silsesquioxane).

8. The resist composition as claimed in claim 1 wherein (B) is poly (methyl-co-t-butoxycarbonyl norbornyl)silsesquioxane.

9. The resist composition as claimed in claim 1 wherein (B) is present in an amount in a range of 20 to 50 parts by weight based on 100 parts by weight of (A).

10. The resist composition as claimed in claim 1 wherein (C) is selected from onium salts, halogen-containing compounds, diazoketone compounds, sulfone compounds, sulfonate compounds.

11. The resist composition as claimed in claim 10 wherein the acid generator is a sulfonate compound.

12. The resist composition as claimed in claim 1 wherein the photo-acid generator is present in an amount in a range of 2 to 5 parts by weight based on 100 parts by weight of (B).

13. The resist composition as claimed in claim 1 wherein there is additionally present (E) at least one additive selected from acid-diffusion controllers, surfactants, dissolution inhibitors, cross-linking agents, sensitizers, halation inhibitors, adhesion promoters, storage stabilizers, anti-foaming agents, coating aids, and plasticizers.

14. The resist composition as claimed in claim 13 wherein (E) is present in amount of less than 20 wt % based on solids.

15. The resist composition as claimed in claim 1 wherein (D) is selected from ether-, ester-, hydroxyl- and ketone-containing compounds.

16. The resist composition as claimed in claim 15 wherein (D) is present in an amount of 80 to 90 wt % based on the weight of the total photoresist composition.

17. A process for generating a resist image on a substrate comprising

(a) coating a substrate with a film comprising the resist composition as claimed in claim 1 ;

(b) imagewise exposing the film to radiation to produce an exposed film; and

(c) developing the exposed film to produce an image.

18. The process as claimed in claim 17 wherein the film is coated on the substrate by spin-coating.

19. The process as claimed in claim 17 wherein the film is dried before exposure to the radiation.

20. The process as claimed in claim 17 wherein the exposed film has a thickness of 0.01 to 5 microns.

21. The process as claimed in claim 17 wherein the radiation is selected from UV, X-ray, e-beam and EUV.

22. The process as claimed in claim 17 wherein the radiation has a wavelength in the range of 157 nm to 365 nm.

23. The process as claimed in claim 17 wherein the radiation has a wavelength in the range of 157 nm to 193 nm.

24. The process as claimed in claim 17 wherein the exposed film is heated at a temperature of 30° C. to 200° C. prior to being developed.

25. The process as claimed in claim 17 wherein the exposed film is developed by contacting the exposed film with an aqueous base solution.