Switchable antireflective coatings

1. An antireflective coating compositions comprising

(I) a silsesquioxane comprising the units

(Ph(CH 2 ) r SiO (3-x)/2 (OR′) x ) m

(HSiO (3-x)/2 (OR′) x ) n

(MeSiO (3-x)/2 (OR′) x ) o

(RSiO (3-x)/2 (OR′) x ) p

(R 1 SiO (3-x)/2 (OR′) x ) q

(II) a compound selected from photo-acid generators and thermal acid generators; and

(III) a solvent

wherein in the silsesquioxane resin Ph is a phenyl group, Me is a methyl group; R′ is hydrogen atom or a hydrocarbon group having from 1 to 4 carbon atoms; each R is a carboxylic acid forming group of general formula —R 2 C(O)OR 3 or a sulfuric acid forming group of general formula —R 2 SO 3 R 3 with optionally trace amounts of the corresponding carboxylic acid or sulfuric acid, wherein R 2 is selected from alkylene groups having 1-10 carbon atoms and polyether groups having the general formula —(CH 2 ) a [O(CH 2 ) b ] f — where a has a value of 1 to 12, b has a value of 2 to 6 and f has a value of 1 to 10 and R 3 is a protecting group selected from t-butyl, trimethylsilyl, anhydride groups, methylthiomethyl ester, benzyloxymethyl ester, diphenylmethyl ester and p-methoxybenzyl ester; and each R 1 is independently selected from substituted phenyl groups, ester groups, polyether groups; mercapto groups, sulfur-containing organic functional groups, hydroxyl producing group, aryl sulfonic ester groups, and reactive or curable organic functional groups; and r has a value of 0, 1, 2, 3, or 4; x has a value of 0, 1 or 2; m has a value of 0 to 0.95; n has a value of 0.05 to 0.95; o has a value of 0 to 0.95; p has a value of 0.05 to 0.5; q has a value of 0 to 0.95; and m+n+o+p+q≈1.

2. The anti-reflective coating composition as claimed in claim 1 wherein compound (II) is a photo-acid generator.

3. The anti-reflective coating composition as claimed in claim 1 wherein compound (II) is a thermal acid generator.

4. The anti-reflective coating composition as claimed in claim 1 wherein the silsesquioxane resin comprises the units

(Ph(CH 2 ) r SiO (3-x)/2 (OR′) x ) m

(HSiO (3-x)/2 (OR′) x ) n

(MeSiO (3-x)/2 (OR′) x ) o

(RSiO (3-x)/2 (OR′) x ) p

where m has a value of 0.05 to 0.25, n has a value of 0.15 to 0.80, o has a value of 0.25 to 0.80 and p has a value of 0.015 to 0.35 and m+n+o+p≈1.

5. The anti-reflective coating composition as claimed in claim 1 wherein the solvent (III) is selected from 1-methoxy-2-propanol, propylene glycol monomethyl ethyl acetate, gamma-butyrolactone, and cyclohexanone.

6. The anti-reflective coating composition as claimed in claim 5 wherein the solvent is present at 10 to 99.9 wt % based on the total weight of the antireflective coating composition.

7. A method for forming an antireflective coating on an electronic device comprising

(A) applying to an electronic device an anti-reflective coating composition according to claim 1 , and,

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

8. A method comprising

(a) forming a antireflective coating on a substrate;

(b) forming a resist coating over the antireflective coating

(c) exposing the resist to radiation;

(d) developing the resist and the antireflective coating;

wherein the antireflective coating is produced from anti-reflective coating composition according to claim 1 .

9. The method as claimed in claim 7 or 8 wherein the antireflective coating composition is applied by spin-coating.

10. The method as claimed in claim 7 or 8 wherein the solvent is removed and the silsesquioxane resin is cured by heating at 80° C. to 450° C. for 0.1 to 60 minutes.

11. A method comprising

(a) applying an antireflective coating composition comprising a silsesquioxane resin and a thermal acid generator on a substrate;

(b) thermally curing the antireflective coating composition to produce a wet-etchable antireflective coating;

(c) forming a resist coating over the antireflective coating;

(d) exposing the resist to radiation;

(e) developing the resist and the antireflective coating

wherein the silsesquioxane resin comprises the units

(Ph(CH 2 ) r SiO (3-x)/2 (OR′) x ) m

(HSiO (3-x)/2 (OR′) x ) n

(MeSiO (3-x)/2 (OR′) x ) o

(RSiO (3-x)/2 (OR′) x ) p

(R 1 SiO (3-x)/2 (OR′) x ) q and

where Ph is a phenyl group, Me is a methyl group; R′ is hydrogen atom or a hydrocarbon group having from 1 to 4 carbon atoms; each R is a carboxylic acid forming group of general formula —R 2 C(O)OR 3 or a sulfuric acid forming group of general formula —R 2 SO 3 R 3 with optionally trace amounts of the corresponding carboxylic acid or sulfuric acid, wherein R 2 is selected from alkylene groups having 1-10 carbon atoms and polyether groups having the general formula —(CH 2 ) a [O(CH 2 ) b ] f — where a has a value of 1 to 12, b has a value of 2 to 6 and f has a value of 1 to 10 and R 3 is a protecting group selected from t-butyl, trimethylsilyl, anhydride groups, methylthiomethyl ester, benzyloxymethyl ester, diphenylmethyl ester and p-methoxybenzyl ester; and R 1 is selected from substituted phenyl groups, ester groups, polyether groups; mercapto groups, sulfur-containing organic functional groups, hydroxyl producing group, aryl sulfonic ester groups, and reactive or curable organic functional groups; and r has a value of 0, 1, 2, 3, or 4; x has a value of 0, 1 or 2; wherein in the resin m has a value of 0 to 0.95; n has a value of 0.05 to 0.95; o has a value of 0 to 0.95; p has a value of 0.05 to 0.5; q has a value of 0 to 0.95; and m+n+o+p+q≈1.

12. A method comprising

(a) forming an antireflective coating (ARC) on a substrate wherein the ARC composition comprises a silsesquioxane resin and a photo-acid generator;

optionally (b) exposing the ARC to radiation to produce a wet-etchable antireflective coating;

(c) forming a resist coating over the antireflective coating;

(d1) exposing the resist and ARC to radiation;

or, when (b) is performed, (d2) exposing the resist to radiation;

(e) developing the resist and the antireflective coating

wherein the silsesquioxane resin is comprised of the units

(Ph(CH 2 ) r SiO (3-x)/2 (OR′) x ) m

(HSiO (3-x)/2 (OR′) x ) n

(MeSiO (3-x)/2 (OR′) x ) o

(RSiO (3-x)/2 (OR′) x ) p

(R 1 SiO (3-x)/2 (OR′) x ) q and

where Ph is a phenyl group, Me is a methyl group; R′ is hydrogen atom or a hydrocarbon group having from 1 to 4 carbon atoms; each R is a carboxylic acid forming group or a sulfuric acid forming group with optionally trace amounts of the corresponding carboxylic acid of general formula —R 2 C(O)OR 3 or sulfuric acid of general formula —R 2 SO 3 R 3 , wherein R 2 is selected from alkylene groups having 1-10 carbon atoms and polyether groups having the general formula —(CH 2 ) a [O(CH 2 ) b ] f — where a has a value of 1 to 12, b has a value of 2 to 6 and f has a value of 1 to 10 and R 3 is a protecting group selected from t-butyl, trimethylsilyl, anhydride groups, methylthiomethyl ester, benzyloxymethyl ester, diphenylmethyl ester and p-methoxybenzyl ester; and R 1 is selected from substituted phenyl groups, ester groups, polyether groups; mercapto groups, sulfur-containing organic functional groups, hydroxyl producing group, aryl sulfonic ester groups, and reactive or curable organic functional groups; and r has a value of 0, 1, 2, 3, or 4; x has a value of 0, 1 or 2; wherein in the resin m has a value of 0 to 0.95; n has a value of 0.05 to 0.95; o has a value of 0 to 0.95; p has a value of 0.05 to 0.5; q has a value of 0 to 0.95; and m+n+o+p+q≈1.