Onium salt, photo-acid generator, chemically-amplified resist composition, and patterning process

Abstract

This invention relates to onium salts represented by general formula (A). It provides onium salts for use in photolithography using high-energy rays, providing high sensitivity and excellent photolithography performance for components such as CDU and LWR. [Chemical 1] m1 is 1 to 4. m2 is 0 or 1. R1 is any one of an electron-withdrawing group such as a hydrogen atom, a hydrocarbon group, or a cyano group. LA and LB are single bonds, carbonyl groups, ether bonds, and ester bonds. At least one of W1 and W2 has an aromatic ring. The portion represented by (W2-[LA-W1]m2-LB-) has at least two iodine atoms directly bonded to the aromatic ring. Z+ is an onium cation.

Claims

1. An onium salt, characterized by being represented by the following general formula (A2); wherein m1 is 1; m3 is 2 or 3; m4 is an integer from 0 to 3; R1 is independently either a hydrogen atom or an electron-withdrawing group, wherein the electron-withdrawing group is a cyano or a nitro group, and one of R1 is the electron-withdrawing group; LB is a single bond, carbonyl group, ether bond, ester bond, amide bond, sulfonate bond, sulfonamide bond, carbonate bond, carbamate bond, or ethylenediamine (-C(=O)C(=O)-) bond; R3 is a chlorine atom, a bromine atom, a nitro group, or an alkyl group with 1 to 20 carbon atoms; Z+ is a strontium cation represented by the following general formula (Z-1) or a monazine cation represented by the following general formula (Z-2); In the formula, Rct1 to Rct5 are each independently a hydrocarbon group with 1 to 30 carbon atoms, which may also contain heteroatoms; furthermore, Rct1 and Rct2 may also bond to each other and form a ring together with the sulfur atoms they are bonded to.

2. As in request item 1, the onium salt, where, The sulfonic acid anion portion of the onium salt is any one of the following formulas (T1), (T3), and (T4): (T1) (T3) (T4).

3. The onium salt of claim 1 is represented by the following general formula (A3); where m3, m4, LB, R1, R3, and Z+ are the same as above; m5 is 0; and R4 and R1 are the same.

4. A photoacid generator, characterized in that it is composed of an onium salt of any one of claims 1 to 3.

5. A chemical amplification inhibitor composition, characterized in that it contains a photoacid generator as claimed in claim 4.

6. The chemical amplification inhibitor composition as described in claim 5 further contains a base polymer.

7. The chemical amplification inhibitor composition as claimed in claim 6, wherein, The basic polymer contains repeating units represented by formula (b1) or (b2); where RA is independently a hydrogen atom or a methyl group; Y1 is a single bond, a p-phenyl or p-naphthyl group, or a linking group containing at least one of the following carbons: ester, ether, and lactone rings, and the p-phenyl, p-naphthyl, and linking group may also contain at least one of the following: hydroxyl, halogen atom, saturated hydrocarbon oxygen group containing 1 to 8 carbons, and saturated hydrocarbon carbonyl oxygen group containing 2 to 8 carbons; Y2 is a single bond or ester bond; Y3 is a single bond, ether bond, or ester bond; R11 and R12 are independently acid-labile groups; R13 is a saturated hydrocarbon group containing 1 to 4 carbons, a halogen atom, a saturated hydrocarbon carbonyl group containing 2 to 5 carbons, a cyano group, or a saturated hydrocarbon oxygen carbonyl group containing 2 to 5 carbons; R14 is a single bond or an alkyldiyl group having 1 to 6 carbon atoms, and the alkyldiyl group may also contain at least one of the following: hydroxyl group, saturated hydrocarbon oxy group having 1 to 8 carbon atoms, saturated hydrocarbon carbonyl oxy group having 2 to 8 carbon atoms, ether bond, and ester bond; a is an integer from 0 to 4.

8. The chemical amplification inhibitor composition of claim 6 further contains at least one selected from organic solvents, quenchers, surfactants, and dissolution inhibitors.

9. A pattern forming method, characterized by comprising the following steps: forming a resist film on a substrate using a chemical amplifying resist composition as claimed in claim 5, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developing solution.

10. The pattern forming method as described in claim 9, wherein, The high-energy rays are KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light with a wavelength of 3~15nm.