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# c12) United States Patent 

# Ohsawa et al. 

# (54) PHOTOACID GENERATOR, RESIST COMPOSITION, AND PATTERNING PROCESS 

(75) Inventors: Youichi Ohsawa, Joetsu (JP); Takeshi Kinsho, Joetsu (JP); Takeru Watanabe, Joetsu (JP); Koji Hasegawa, Joetsu (JP); Masaki Ohashi, Joetsu (JP) 

(73) Assignee: Shin-Etsu Chemical Co., Ltd., Tokyo (JP) 

( *) Notice: Subject to any disclaimer, the term ofthis patent is extended or adjusted under 35 U.S.C. 154(b) by 511 days. 

(21) Appl. No.: 12/410,357 

(22) Filed: Mar. 24, 2009 

(65) Prior Publication Data 

US 2009/0246694 Al Oct. 1, 2009 

## (30) Foreign Application Priority Data 

Mar. 25, 2008 (JP) ................................. 2008-078049 

(51) Int. Cl. 

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(52) U.S. Cl. ..................... 430/270.1; 430/326; 430/330; 430/91 O; 549/269; 549/300; 562/30; 562/111; 562/113 

(58) Field of Classification Search ............... 430/270.1, 430/326, 330, 910; 549/269, 300; 562/30, 562/111, 113 See application file for complete search history. 

## (56) References Cited 

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## U.S. PATENT DOCUMENTS 

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# (IO) Patent No.: US 8,114,570 B2 

# (45) Date of Patent: Feb.14,2012 

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Choi et al., "Improved Lithographic Performance with Ultra-thin 193 nm Resist" Journal of Photopolymer Science and Technology, vol. 19, No. 3, 2006, pp. 313-318. 

Lowe, "Synthesis of sulphonium salts" The chemistry of the sulphortiunn group Part 1, John Wiley & Sons, 1981, Chapter 11, pp. 267-312. 

Devoe et al., "Photochemistry and Photophysics of Onium Salts*" Advances in Photochemistry, vol. 17, 1992 by John Wiley & Sons, pp. 313-320. 

Primary Examiner - John Chu (74) Attorney, Agent, or Firm -Birch, Stewart, Kolasch & Birch, LLP 

## (57) ABSTRACT 

Photoacid generators generate sulfonic acids of formula (la) upon exposure to high-energy radiation. 

RO is OH or C$_{1}$-C$_{20 }$organoxy, R 1 is a divalent C$_{1}$-C$_{20 }$ali› phatic group or forms a cyclic structure with RO. The photo› acid generators are compatible with resins and can control acid diffusion and are thus suited for use in chemically ampli› fied resist compositions. 

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US008114570B2 

## FOREIGN PATENT DOCUMENTS 

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## OTHER PUBLICATIONS 

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## 16 Claims, 4 Drawing Sheets 

