Upper layer-forming composition and photoresist patterning method
An upper layer-forming composition includes a resin, and a solvent. The resin is dissolvable in a developer for a photoresist film which is to be covered by the upper layer-forming composition to form a pattern by exposure to radiation. The solvent dissolves the resin in the solvent. The solvent includes a compound shown by a formula (1). Each of R 1 and R 2 independently represents a hydrocarbon group having 1 to 8 carbon atoms or a halogenated hydrocarbon group. R 1 —O—R 2 (1)
1. An upper layer-forming composition comprising:
a resin dissolvable in a developer for a photoresist film which is to be covered by the upper layer-forming composition to form a pattern by exposure to radiation; and
a solvent to dissolve the resin in the solvent, the solvent including a compound shown by a formula (1),
R 1 —O—R 2 (1)
wherein each of R 1 and R 2 independently represents a hydrocarbon group having 1 to 8 carbon atoms or a halogenated hydrocarbon group.
2. The upper layer-forming composition according to claim 1 , wherein the solvent does not cause intermixing of the photoresist film and the upper layer-forming composition.
3. The upper layer-forming composition according to claim 1 , wherein the solvent further includes a monohydric alcohol having 1 to 10 carbon atoms.
4. The upper layer-forming composition according to claim 2 , wherein the solvent further includes a monohydric alcohol having 1 to 10 carbon atoms.
5. The upper layer-forming composition according to claim 1 , wherein the resin includes a first recurring unit having a group shown by a formula (2), a second recurring unit having a group shown by a formula (3), a third recurring unit having a group shown by a formula (4), a fourth recurring unit having a carboxyl group, a fifth recurring unit having a sulfo group, or a combination thereof and has a weight average molecular weight measured by gel permeation chromatography of 2,000 to 100,000,
wherein
each of R 3 and R 4 independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluoroalkyl group having 1 to 4 carbon atoms,
R 5 represents a fluoroalkyl group having 1 to 20 carbon atoms,
and
R 6 represents an organic group having a polar group.
6. The upper layer-forming composition according to claim 1 , further comprising:
an acid, an acid-generator which generates an acid by being exposed to radiation, or a combination of the acid and the acid-generator.
7. A photoresist patterning method comprising:
applying a photoresist composition to a substrate to form a photoresist film;
applying the upper layer-forming composition according to claim 1 on the photoresist film to form an upper layer film;
irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and
developing the resist pattern.
8. A photoresist patterning method comprising:
applying a photoresist composition to a substrate to form a photoresist film;
applying the upper layer-forming composition according to claim 2 on the photoresist film to form an upper layer film;
irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and
developing the resist pattern.
9. A photoresist patterning method comprising:
applying a photoresist composition to a substrate to form a photoresist film;
applying the upper layer-forming composition according to claim 3 on the photoresist film to form an upper layer film;
irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and
developing the resist pattern.
10. A photoresist patterning method comprising:
applying a photoresist composition to a substrate to form a photoresist film;
applying the upper layer-forming composition according to claim 4 on the photoresist film to form an upper layer film;
irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and
developing the resist pattern.
11. A photoresist patterning method comprising:
applying a photoresist composition to a substrate to form a photoresist film;
applying the upper layer-forming composition according to claim 5 on the photoresist film to form an upper layer film;
irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and
developing the resist pattern.
12. A photoresist patterning method comprising:
applying a photoresist composition to a substrate to form a photoresist film;
applying the upper layer-forming composition according to claim 6 on the photoresist film to form an upper layer film;
irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and
developing the resist pattern.