Copolymer and associated layered article, and device-forming method

Patent metadata

Field	Value
Publication number	US-9957339-B2
Application number	US-201514820699-A
Country	US
Kind code	B2
Filing date	Aug 7, 2015
Priority date	Aug 7, 2015
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A copolymer is prepared by the polymerization of monomers that include an ultraviolet absorbing monomer, and a base-solubility-enhancing monomer. The copolymer is useful for forming a topcoat layer for electron beam and extreme ultraviolet lithographies. Also described are a layered article including the topcoat layer, and an associated method of forming an electronic device.

First claim

The invention claimed is:

1. A copolymer,
wherein the copolymer comprises the polymerization product of monomers comprising:
an out-of-band absorbing monomer comprising an unsubstituted or substituted C 6 -C 18 aryl group that is free of fluorine, an unsubstituted or substituted C 2 -C 17 heteroaryl group, a C 5 -C 12 dienone group, or a combination thereof; and
a base-solubility-enhancing monomer selected from the group consisting of (meth)acrylate esters of poly(ethylene oxide)s, (meth)acrylate esters of poly(propylene oxide)s, base-labile (meth)acrylate esters, (meth)acrylate esters substituted with a group having a pK a of 2 to 12, and combinations thereof;

wherein the out-of-band absorbing monomer comprising an unsubstituted or substituted C 6 -C 18 aryl group that is free of fluorine has the structure

wherein
R 1 is hydrogen or methyl,
n is 0, 1, 2, 3, or 4, and
Ar 1 is an unsubstituted or substituted C 6 -C 18 aryl group that is free of fluorine;

wherein a film cast from the copolymer has an extinction coefficient, k, of 0.1 to 0.5 at a wavelength in the range of 150 to 400 nanometers; and
wherein the copolymer has a dispersity (M w /M n ) of 1.05 to 1.2.

2. The copolymer of claim 1 , wherein the base-solubility-enhancing monomer comprises a (meth)acrylate ester of a poly(ethylene oxide) and a (meth)acrylate ester substituted with a 1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl group.

3. A method of forming a polymer layer, comprising spin-coating a polymer solution comprising 0.1 to 3 weight percent of the copolymer of claim 1 in a solvent selected from the group consisting of 2-methyl-2-butanol, 2-methyl-2-pentanol, combinations of 2-methyl-2-butanol and 2-methyl-2-pentanol, combinations of dipropylene glycol monomethyl ether and 2-methyl-2-butanol containing at least 90 weight percent 2-methyl-2-butanol, combinations of dipropylene glycol monomethyl ether and 2-methyl-2-pentanol containing at least 90 weight percent 2-methyl-2-pentanol, and combinations of dipropylene glycol monomethyl ether and 2-methyl-2-butanol and 2-methyl-2-pentanol containing at least 90 weight percent total of 2-methyl-2-butanol and 2-methyl-2-pentanol.

4. A layered article comprising:
a substrate;
a photoresist layer over the substrate; and
a topcoat layer comprising the copolymer of claim 1 , over and in contact with the photoresist layer.

5. A method of forming an electronic device, comprising:
(a) applying a photoresist layer onto a substrate;
(b) applying a topcoat layer comprising the copolymer of claim 1 , onto the photoresist layer;
(c) pattern-wise exposing the photoresist layer through the topcoat layer to activating radiation; and
(d) developing the exposed photoresist layer to provide a resist relief image.

6. The method of claim 5 , wherein the activating radiation comprises electron beam or extreme ultraviolet radiation.

7. A copolymer,
wherein the copolymer comprises the polymerization product of monomers comprising:
an out-of-band absorbing monomer having the structure

wherein R 1 is hydrogen or methyl, n is 0, 1, 2, 3, or 4, and Ar 1 is an unsubstituted or substituted C 6 -C 18 aryl group that is free of fluorine; and
a base-solubility-enhancing monomer comprising a (meth)acrylate ester of a poly(ethylene oxide) and a (meth)acrylate ester substituted with a 1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl group;
wherein the monomers comprise, based on the total moles of monomer,
30 to 50 mole percent of the out-of-band absorbing monomer, 30 to 50 mole percent of the (meth)acrylate ester of a poly(ethylene oxide), and
10 to 30 mole percent of the (meth)acrylate ester substituted with a 1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl group;

wherein the copolymer has a dispersity (M w /M n ) of 1.05 to 1.2; and
wherein a film cast from the copolymer has an extinction coefficient, k, of 0.1 to 0.5 at a wavelength in the range of 150 to 400 nanometers.

8. A copolymer,
wherein the copolymer comprises the polymerization product of monomers comprising:
an out-of-band absorbing monomer comprising an unsubstituted or substituted C 6 -C 18 aryl group that is free of fluorine, an unsubstituted or substituted C 2 -C 17 heteroaryl group, a C 5 -C 12 dienone group, or a combination thereof; and
a base-solubility-enhancing monomer selected from the group consisting of (meth)acrylate esters of poly(ethylene oxide)s, (meth)acrylate esters of poly(propylene oxide)s, base-labile (meth)acrylate esters, (meth)acrylate esters substituted with a group having a pK a of 2 to 12, and combinations thereof;

wherein the base-solubility-enhancing monomer comprises a (meth)acrylate ester of a poly(ethylene oxide) and a (meth)acrylate ester substituted with a 1,1,1,3,3,3-hexafluoro-2-hydroxy-2-propyl group;
wherein a film cast from the copolymer has an extinction coefficient, k, of 0.1 to 0.5 at a wavelength in the range of 150 to 400 nanometers; and
wherein the copolymer has a dispersity (M w /M n ) of 1.05 to 1.2.

Assignees

• Univ Queensland
• Rohm & Haas Elect Mat

Inventors

• Thackeray James W
• Du Ke
• Trefonas Iii Peter
• Blakey Idriss
• Whittaker Andrew Keith

Classifications

• C10N2040/42

  Flashing oils or marking oils · CPC title

• G03F7/091

  characterised by antireflection means or light filtering or absorbing means, e.g. anti-halation, contrast enhancement · CPC title

• A24B1/04 Primary

  Sifting, sorting, cleaning or removing impurities from tobacco · CPC title

• G03F7/20

  Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00) · CPC title

• C09D151/08

  grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title