US 12,222,649 B2
Positive resist composition and pattern forming process
Jun Hatakeyama, Joetsu (JP); and Koji Hasegawa, Tokyo (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed on Jan. 7, 2022, as Appl. No. 17/570,612.
Claims priority of application No. 2021-010844 (JP), filed on Jan. 27, 2021.
Prior Publication US 2022/0244643 A1, Aug. 4, 2022
Int. Cl. G03F 7/039 (2006.01); G03F 7/004 (2006.01); G03F 7/20 (2006.01); G03F 7/32 (2006.01); G03F 7/38 (2006.01); G03F 7/40 (2006.01)
CPC G03F 7/0397 (2013.01) [G03F 7/0045 (2013.01); G03F 7/2006 (2013.01); G03F 7/322 (2013.01); G03F 7/38 (2013.01); G03F 7/40 (2013.01)] 13 Claims
 
1. A positive resist composition comprising a base polymer comprising repeat units (a) having the structure of a sulfonium salt of a fluorinated phenol compound; wherein the repeat units (a) have the formula (a):

OG Complex Work Unit Chemistry
wherein RA is hydrogen or methyl,
X1 is, an ester bond, ether bond, phenylene group or naphthylene group,
X2 is a single bond, a phenylene group, or a C1-C12 saturated hydrocarbylene group which may contain an ether bond, ester bond, amide bond, lactone ring or sultone ring,
X3 is a single bond, ester bond or ether bond,
Rf is a fluorine atom, trifluoromethyl, trifluoromethoxy, or trifluoromethylthio group,
R1 is a C1-C4 alkyl group,
R2 to R4 are each independently a halogen or a C1-C20 hydrocarbyl group which may contain a heteroatom, R2 and R3 may bond together to form a ring with the sulfur atom to which they are attached,
m is an integer of 1 to 4, n is an integer of 0 to 3, and m+n is from 1 to 4.