US-12625431-B2 - EUV resist underlayer film-forming composition

Abstract

A composition for forming a resist underlayer film that enables the formation of a desired resist pattern; and a method for producing a resist pattern and a method for producing a semiconductor device, each of which uses the composition for forming a resist underlayer film. The composition for forming an EUV resist underlayer film has a basic organic group substituted with a protective group on a side chain of a (meth)acrylic polymer and further includes a solvent, but does not include a polymer other than the (meth)acrylic polymer. The organic group is an acyloxy group that has an amino group substituted with a protective group, or that has a nitrogen-containing heterocycle substituted with a protective group.

Inventors

• Shou SHIMIZU
• Mamoru Tamura

Assignees

• NISSAN CHEMICAL CORPORATION

Dates

Publication Date

20260512

Application Date

20210205

Priority Date

20200207

Claims (9)

1. 1 . An EUV resist underlayer film-forming composition comprising a (meth)acrylic polymer having a basic organic group substituted with a protecting group on a side chain thereof and further comprising an organic solvent, and comprising no polymer other than the (meth)acrylic polymer, wherein the protecting group is selected from a benzyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, a 2,2,2-trichloroethoxycarbonyl group and an allyloxycarbonyl group.
2. 2 . The EUV resist underlayer film-forming composition according to claim 1 , wherein the (meth)acrylic polymer is a polymer having a unit structure represented by the following formula (1): wherein, R 1 represents a hydrogen atom or a methyl group, L represents a divalent linking group, and X represents an acyloxy group having an amino group substituted with a protecting group or an acyloxy group having a nitrogen-containing heterocyclic ring substituted with a protecting group.
3. 3 . The EUV resist underlayer film-forming composition according to claim 1 , further comprising a crosslinking catalyst.
4. 4 . The EUV resist underlayer film-forming composition according to claim 1 , further comprising a crosslinking agent.
5. 5 . An EUV resist underlayer film, which is a baked product of an applied film consisting of the EUV resist underlayer film-forming composition according to claim 1 .
6. 6 . The EUV resist underlayer film-forming composition according to claim 2 , wherein L in formula (1) represents a —C(═O)OR 2 — group, wherein R 2 represents an alkylene group having 1 to 10 carbon atoms, part of the hydrogen atoms of the alkylene group being replaced by a hydroxy group.
7. 7 . An EUV resist underlayer film, which is a baked product of an applied film consisting of the EUV resist underlayer film-forming composition according to claim 2 .
8. 8 . An EUV resist underlayer film, which is a baked product of an applied film consisting of the EUV resist underlayer film-forming composition according to claim 3 .
9. 9 . An EUV resist underlayer film, which is a baked product of an applied film consisting of the EUV resist underlayer film-forming composition according to claim 4 .

Description

TECHNICAL FIELD The present invention relates to a composition used in a lithography process in the production of a semiconductor, particularly in the state-of-the-art (ArF, EUV, EB, and the like) lithography process. In addition, the present invention relates to a method for producing a substrate having a resist pattern applied with the resist underlayer film, and a method for producing a semiconductor device. BACKGROUND ART Conventionally, lithographic microfabrication using resist compositions has been used in the production of semiconductor devices. Microfabrication is a processing method which includes forming a thin film of photoresist composition on a semiconductor substrate such as silicon wafer, irradiating the film with active beams such as ultraviolet rays through a mask pattern on which a device pattern is drawn, developing this, and then performing etching treatment on the substrate with the obtained photoresist pattern as a protective film, thereby forming micro unevenness corresponding to said pattern on the substrate surface. In recent years, because semiconductor devices have become more highly integrated, as the active beams used, EUV light (wavelength: 13.5 nm) or EB (electron beams) for cutting-edge microfabrication has also been examined for application, in addition to the conventionally used i-line (wavelength of 365 nm), KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength: 193 nm). In line with this, the defects of resist pattern formation due to the influences from the semiconductor substrates and the like have become a major problem. To solve this problem, a method of providing a resist underlayer film between the resist and the semiconductor substrate has been widely examined. To solve this problem, a method of providing a resist underlayer film between the resist and the semiconductor substrate has been widely examined. Patent Literature 1 discloses an additive for a resist underlayer film-forming composition to increase the adhesion of the resist pattern formed on the resist underlayer film. CITATION LIST Patent Literature Patent Literature 1: WO 2013/058189 A1 SUMMARY OF INVENTION Technical Problem The properties required for the resist underlayer film include, for example, not intermixing with the resist film formed on the upper layer (insoluble in resist solvent) and a higher dry etching speed than the resist film. In the case of lithography with EUV exposure, the line width of the resist pattern formed is 32 nm or less, and the resist underlayer film for EUV exposure is formed to have a thinner film thickness than the conventional films and then is subjected for use. When forming such thin films, pinholes, agglomerations, and the like, easily occur due to the influences from the substrate surface and polymers used, making it difficult to form a uniform film without defects. On the other hand, when forming resist patterns, in the development step, a method which uses a solvent, generally an organic solvent, that could dissolve a resist film for removing an unexposed part of the resist film, and leaving the exposed part of the resist film as a resist pattern may be adopted. In such a negative development process, improving the adhesion of the resist pattern is a major issue. In addition, it is desired to suppress the deterioration of LWR (Line Width Roughness) when forming a resist pattern, to form a resist pattern with a good rectangular shape, and to improve resist sensitivity. An object of the present invention is to provide a composition for forming a resist underlayer film capable of forming a desired resist pattern and a resist pattern forming method using the resist underlayer film-forming composition, which allow to solve the above-mentioned problems. Solution to Problem The present invention encompasses the followings. [1] An EUV resist underlayer film-forming composition comprising a (meth)acrylic polymer having a basic organic group substituted with a protecting group on a side chain thereof and further comprising an organic solvent, and comprising no polymer other than the (meth)acrylic polymer. [2] The EUV resist underlayer film-forming composition according to [1], wherein the organic group is an acyloxy group having an amino group substituted with a protecting group or an acyloxy group having a nitrogen-containing heterocyclic ring substituted with a protecting group. [3] The EUV resist underlayer film-forming composition according to [1] or [2], wherein the protecting group is selected from a tert-butoxycarbonyl group, a benzyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, a 2,2,2-trichloroethoxycarbonyl group and an allyloxycarbonyl group. [4] The EUV resist underlayer film-forming composition according to any one of [1] to [3], wherein the (meth)acrylic polymer is a polymer having a unit structure represented by the following formula (1): (wherein, R1 represents a hydrogen atom or a methyl group, L represents a divalent linking grou