US 12,253,802 B2
Positive resist composition and pattern forming process
Jun Hatakeyama, Joetsu (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed on Jan. 5, 2022, as Appl. No. 17/568,870.
Claims priority of application No. 2021-008403 (JP), filed on Jan. 22, 2021.
Prior Publication US 2022/0252983 A1, Aug. 11, 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)] 11 Claims
 
1. A positive resist composition comprising a base polymer comprising repeat units (a) consisting of a fluorinated carboxylate anion, fluorinated phenoxide anion, fluorinated sulfonamide anion, fluorinated alkoxide anion, fluorinated 1,3-diketone anion, fluorinated β-keto ester anion or fluorinated imide anion and a nitrogen-containing cation having a tertiary ester structure, and repeat units (b1) having a carboxy group in which the hydrogen is substituted by an acid labile group and/or repeat units (b2) having a phenolic hydroxy group in which the hydrogen is substituted by an acid labile group,
wherein the repeat units (a) have the formula (a):

OG Complex Work Unit Chemistry
wherein RA is hydrogen or methyl,
X1 is each independently a single bond, phenylene, naphthylene, or a C1-C16 linking group containing an ester bond, ether bond or lactone ring, and
R is a nitrogen-containing tertiary hydrocarbon group having the formula (a1) or (a2):

OG Complex Work Unit Chemistry
wherein R1, R2 and R3 are each independently a C1-C8 aliphatic hydrocarbyl group or C6-C10 aryl group, which may contain an ether bond, ester bond, halogen or trifluoromethyl,
RN1 and RN2 are each independently hydrogen, or a C1-C10 alkyl or C2-C10 alkoxycarbonyl group which may contain an ether bond,
the circle Ra is a C2-C10 alicyclic group including the nitrogen atom,
the broken line designates a valence bond, and
X− is a fluorinated carboxylate anion, fluorinated phenoxide anion, fluorinated sulfonamide anion, fluorinated alkoxide anion, fluorinated 1,3-diketone anion, fluorinated β-keto ester anion or fluorinated imide anion,
wherein the fluorinated carboxylate anion has the formula (Xa), the fluorinated phenoxide anion has the formula (Xb), the fluorinated sulfonamide anion has the formula (Xc) and the fluorinated alkoxide anion has the formula (Xd), the fluorinated 1,3-diketone anion, fluorinated β-keto ester anion and fluorinated imide anion have the formula (Xe):

OG Complex Work Unit Chemistry
wherein R4 and R6 are each independently fluorine or a C1-C30 fluorinated hydrocarbyl group which may contain at least one moiety selected from among an ester bond, lactone ring, ether bond, carbonate bond, thioether bond, hydroxy, amino, nitro, cyano, sulfo, sulfonic ester bond, and chlorine,
Rf is fluorine, trifluoromethyl or 1,1,1-trifluoro-2-propanol,
R5 is chlorine, hydroxy, a C1-C6 saturated hydrocarbyloxy group, C2-C6 saturated hydrocarbyloxycarbonyl group, amino group or nitro group,
R7 is hydrogen or a C1-C3 hydrocarbyl group which may contain an ester bond, ether bond, thioether bond, carbonyl, sulfonyl, carbonate, carbamate, sulfone, amino, amide bond, hydroxy, thiol, or nitro, wherein the C1-C3 hydrocarbyl group does not contain halogen,
R8 is trifluoromethyl, a C1-C20 hydrocarbyloxy group, or C2-C21 hydrocarbyloxycarbonyl group, the hydrocarbyl moiety in the hydrocarbyloxy group and hydrocarbyloxycarbonyl group may contain at least one moiety selected from an ether bond, ester bond, thiol, cyano, nitro, hydroxy, sultone, sulfonic ester bond, amide bond, and halogen,
R9 and R10 are each independently a C1-C10 alkyl group or phenyl group, at least one hydrogen in one or both of R9 and R10 is substituted by fluorine,
X is —C(H)═ or —N═,
m is an integer of 1 to 5, n is an integer of 0 to 3, and m+n is from 1 to 5.