JP-7856150-B2 - Radiation-sensitive resin composition and method for forming a resist pattern

Inventors

• 大宮 拓也
• 錦織 克聡
• 桐山 和也
• 松村 裕史
• 寺田 望

Assignees

• ＪＳＲ株式会社

Dates

Publication Date

20260511

Application Date

20230330

Priority Date

20220622

Claims (6)

1. A polymer having a first structural unit represented by the following formula (1), wherein its solubility in a developer changes upon the action of an acid, A radiation-sensitive acid generator, A radiation-sensitive resin composition containing an acid diffusion control agent having a monovalent radiation-sensitive onium cation and a monovalent organic acid anion. (In formula (1), R 1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L 1 is a single bond or a divalent linking group. Ar 1 is a group obtained by removing one hydrogen atom from a substituted or unsubstituted condensed tetracyclic aromatic hydrocarbon ring with 16 or more members.)
2. The radiation-sensitive resin composition according to claim 1, wherein the number of ring members of the condensed tetracyclic aromatic hydrocarbon ring is 16 or more and 18 or less.
3. The radiation-sensitive resin composition according to claim 1, wherein the above-mentioned condensed tetracyclic aromatic hydrocarbon ring is a pyrene ring.
4. The radiation-sensitive resin composition according to claim 1, wherein the polymer further comprises a second structural unit containing an acid-dissociable group.
5. The radiation-sensitive resin composition according to claim 1, wherein the polymer further comprises a third structural unit containing a phenolic hydroxyl group.
6. A step of coating a substrate directly or indirectly with the radiation-sensitive resin composition described in any one of claims 1 to 5 , A step of exposing the resist film formed by the above coating, A method for forming a resist pattern, comprising the step of developing the above-mentioned exposed resist film.

Description

The present invention relates to a radiation-sensitive resin composition and a method for forming a resist pattern. The radiation-sensitive resin composition used in microfabrication by lithography generates acid in the exposed areas by irradiation with radiation such as far ultraviolet light (ArF excimer laser light, wavelength 193 nm) and KrF excimer laser light (wavelength 248 nm), electromagnetic waves such as extreme ultraviolet light (EUV), wavelength 13.5 nm, and charged particle beams such as electron beams. A chemical reaction catalyzed by this acid causes a difference in the dissolution rate in the developer between the exposed and unexposed areas, thereby forming a resist pattern on the substrate. Radiation-sensitive resin compositions are required to have good sensitivity to exposure light such as extreme ultraviolet light and electron beams, as well as excellent LWR (Line Width Roughness) performance. Furthermore, with the further miniaturization of resist patterns, even slight variations in exposure and development conditions have an increasingly significant impact on the shape of the resist pattern and the occurrence of defects. Therefore, there is a need for radiation-sensitive resin compositions with a wide process window (process margin) that can absorb such slight variations in process conditions. In response to these requirements, the types and molecular structures of polymers, acid generators, and other components used in radiation-sensitive resin compositions have been investigated, and their combinations have also been studied in detail (see Japanese Patent Publication No. 2010-134279, Japanese Patent Publication No. 2014-224984, and Japanese Patent Publication No. 2016-047815). Japanese Patent Publication No. 2010-134279Japanese Patent Publication No. 2014-224984Japanese Patent Publication No. 2016-047815 The radiation-sensitive resin composition and resist pattern formation method of the present invention will be described in detail below. <Radiation-sensitive resin composition> The radiation-sensitive resin composition contains [A] a polymer, [B] an acid generator, and [C] an acid diffusion control agent. The radiation-sensitive resin composition usually contains an organic solvent (hereinafter also referred to as "[D] organic solvent"). The radiation-sensitive resin composition may contain other optional components as long as they do not impair the effects of the present invention. The radiation-sensitive resin composition contains [A] polymer, [B] acid generator, and [C] acid diffusion control agent, resulting in excellent sensitivity and LWR performance, and a wide process window. The reason why the radiation-sensitive resin composition achieves the above effects through the above configuration is not entirely clear, but it can be inferred, for example, as follows: That is, because the [A] polymer has a first structural unit represented by formula (1) described later, it is thought that the amount of acid generated from the [B] acid generator etc. upon exposure increases. And, as the amount of acid generated from the [B] acid generator etc. increases, it is thought that the change in solubility in the developer increases due to the action of the acid possessed by the [A] polymer. As a result, it is thought that the above effects are achieved. The radiation-sensitive resin composition can be prepared by mixing, for example, [A] polymer, [B] acid generator, and [C] acid diffusion control agent, and optionally [D] organic solvent and other optional components in predetermined proportions, and preferably by filtering the resulting mixture through a membrane filter with a pore size of 0.20 μm or less. The following describes each component contained in the radiation-sensitive resin composition. <[A] Polymer> [A] The polymer has a first structural unit represented by formula (1) described below (hereinafter also referred to as "structural unit (I)"). [A] The polymer is a polymer whose solubility in a developer changes upon the action of an acid. The radiation-sensitive resin composition may contain one or more [A] polymers. [A] The polymer preferably further has a second structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (II)"). [A] The polymer preferably further has a third structural unit containing a phenolic hydroxyl group (hereinafter also referred to as "structural unit (III)"). [A] The polymer may further have other structural units other than structural units (I) to (III) (hereinafter simply referred to as "other structural units"). [A] The polymer may have one or more of each structural unit. Furthermore, the structural units of polymer [A] may be considered to belong to two or more classifications of structural units. For example, a structural unit may be considered to belong not only to structural unit (I) but also to structural units other than structural unit (I). In such cases, this specification will treat the structur