Aqueous antireflective coatings for photoresist compositions

Abstract

The present invention relates to a novel aqueous antireflective coating solution and a process for its use in photolithography. The antireflective coating solution comprises a novel polymer and water, where the novel polymer of the antireflective coating comprises at least one unit containing a dye that absorbs from about 180 nm to about 450 nm, at least one unit containing a crosslinking group and at least one unit derived from a hydrophilic vinyl monomer or a vinyl monomer capable of becoming hydrophilic.

Description

Claims

1. An aqueous antireflective coating composition for use in photolithography, comprising water and a polymer containing:

a) at least one dye unit having the structure: ##STR1## where R.sub.1 -R.sub.4 is H, (C.sub.1 -C.sub.4) alkyl or (C.sub.1 -C.sub.4) alkoxy,

R.sub.5 is OH, NH.sub.2, OCH.sub.3 or OCH.sub.2 CH.sub.3,

R.sub.6 is H, (C.sub.1 -C.sub.4) alkyl or (C.sub.1 -C.sub.4) alkoxy,

R.sub.7 is H, (C.sub.1 -C.sub.4) alkyl or (C.sub.1 -C.sub.4) alkoxy, or nitro,

R.sub.8 is nitro, SONH.sub.2, COOY, SO.sub.3 Y, where Y is H, alkali metal, ammonium or alkyl ammonium,

X is a conjugated moiety e.g. N.dbd.N, CZ.dbd.CZ, CZ.dbd.N, N.dbd.CZ, where Z is H, (C.sub.1 -C.sub.4) alkyl or (C.sub.1 -C.sub.4) alkoxy,

m=1-3, and n=1-4;

b) at least one unit having the structure ##STR2## where R.sub.1 -R.sub.4 is H, (C.sub.1 -C.sub.4) alkyl or (C.sub.1 -C.sub.4) alkoxy and Y contains a crosslinking group; and

c) at least one unit derived from a hydrophilic vinyl monomer or a vinyl monomer capable of becoming hydrophilic.

2. The aqueous antireflective composition according to claim 1, where the hydrophilic vinyl monomer has the structure: ##STR3## where R.sub.1 -R.sub.3 is H, (C.sub.1 -C.sub.4) alkyl or (C.sub.1 -C.sub.4) alkoxy and W is a hydrophilic group.

3. The aqueous antireflective composition according to claim 2, wherein the hydrophilic group is selected from a group consisting of O(CH.sub.2).sub.2 --O--(CH.sub.2)--OH, O(CH.sub.2).sub.2 --OH, (CH.sub.2).sub.n --OH (where n=1-4), COO(C.sub.1 -C.sub.4)alkyl, COOX, SO.sub.3 X (where X is H, alkali metal, ammonium, alkyl ammonium) and CONHCH.sub.2 OH.

4. The aqueous antireflective composition according to claim 1, where the hydrophilic vinyl monomer is selected from a group consisting of maleic anhydride, fumaric anhydride, vinyl pyridines, and vinyl pyrollidones.

5. The aqueous antireflective composition according to claim 1, wherein the crosslinking group is selected from a group consisting of carbodiimide, isocyanate, blocked isocyanate, glycidyl methacrylate, alkylol acrylamide, alkylol methacrylamide and methyl acrylamidoglycolate.

6. The aqueous antireflective composition according to claim 1, wherein X in the dye unit is an azo group.

7. The aqueous antireflective composition according to claim 1, further comprising a water miscible alcohol or acetate.

8. The aqueous antireflective composition according to claim 1, wherein the dye unit ranges from about 5 to about 95 mole percent, the crosslinking unit ranges from about 1 to about 50 mole percent and the hydrophilic vinyl monomer ranges from about 1 to about 50 mole percent of the polymer.

9. The aqueous antireflective composition according to claim 1, wherein the polymer further comprises one or more vinyl monomers that are nonabsorbing, noncrosslinking and nonhydrophilic.

10. The aqueous antireflective composition according to claim 1, wherein the composition further comprises a crosslinking agent.

11. The aqueous antireflective composition according to claim 1, wherein the composition further comprises a dye.

12. The antireflective composition according to claim 1, wherein the polymer has a weight average molecular weight in the range of about 2,500 to about 1,000,000.

13. The antireflective composition according to claim 1, wherein the metal ion level is less than 50 ppb each metal ion.

14. The process of forming an image on a substrate comprising the steps of:

a) coating the substrate with the antireflective coating composition of claim 1,

b) heating the antireflective coating,

c) coating a photoresist solution on the substrate,

d) heating the photoresist coating to substantially remove solvent from the coating,

e) imagewise exposing the photoresist coating,

f) developing an image using an aqueous alkaline developer,

g) optionally, heating the substrate prior to and after development,

h) dry etching the antireflective coating.

15. The process of claim 14, wherein the photoresist solution comprises a novolak resin, a photosensitive compound and a solvent.

16. The process of claim 14, wherein the photoresist solution comprises a substituted polyhydroxystyrene, a photoactive compound and a solvent.

17. The process of claim 14, wherein the photoresist solution comprises polyhydroxystyrene, a photoactive compound, a dissolution inhibitor and a solvent.

18. The process of claim 14, wherein the heating temperature for hardening of the antireflective coating ranges from about 70.degree. C. to about 250.degree. C.

19. The process of claim 14, wherein the aqueous alkaline developer comprises tetramethyl ammonium hydroxide.