Method for forming anti-reflective coating

1. A method of forming an antireflective coating (ARC) on an electronic device comprising

(A) applying to an electronic device an ARC composition comprising

(i) a silsesquioxane resin having the formula

(PhSiO (3-x)/2 (OH) x ) m (HSiO (3-x)/2 (OH) x ) n (MeSiO (3-x)/2 (OH) x ) p

where Ph is a phenyl group, Me is a methyl group, x has a value of 0, 1 or 2; m has a value of 0.05 to 0.95, n has a value of 0.05 to 0.95, p has a value of 0.05 to 0.95, and m+n+p≈1; and

(ii) a solvent selected from 1-methoxy-2-propanol, propylene methyl ether acetate and cyclohexanone; and

(B) removing the solvent and curing the silsesquioxane resin to form an antireflective coating on the electronic device.

2. The method as claimed in claim 1 wherein m has a value of 0.05 to 0.50, n has a value of 0.10 to 0.70 and p has a value of 0.10 to 0.70.

3. The method as claimed in claim 1 wherein in the silsesquioxane resin less than 40 mole % of the units contains Si—OH groups.

4. The method as claimed in claim 1 wherein in the silsesquioxane resin 6 to 38 mol % of the units contain Si—OH groups.

5. The method as claimed in claim 1 wherein the ARC composition contains 80 to 95 wt % of solvent, based on the weight of the ARC composition.

6. The method as claimed in claim 1 wherein the ARC composition additionally contains a cure catalyst.

7. The method as claimed in claim 1 wherein the ARC composition is applied by spin-coating.

8. The method as claimed in claim 1 wherein the silsesquioxane resin is cured by heating.

9. The method as claimed in claim 8 wherein the silsesquioxane resin is cured by heating at a temperature in the range of 150° C. to 275° C.

10. The method as claimed in claim 1 wherein the silsesquioxane resin is cured by heating at a temperature in the range of 200° C. to 250° C.

11. The method as claimed in claim 1 wherein the silsesquioxane resin is cured by heating in an inert atmosphere.

12. A method of forming a resist image on an electronic device comprising the method according to claim 1 , further comprising the step of (C) forming a resist image over the antireflective coating.

13. The method as claimed in claim 12 wherein the resist image is formed by

(a) forming a film of a resist composition on top of the anti-reflective coating;

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

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

14. A method of forming a pattern on an antireflective coating on an electronic device comprising the method according to claim 12 , further comprising the step of (D) etching a pattern in the anti-reflective coating.

15. The method according to claim 14 , further comprising the step of (E) removing the resist image and the anti-reflective coating.