content_image/915690.jpg
## RESIST COMPOSITION AND PATTERNING PROCESS 

## CROSS-REFERENCE TO RELATED APPLICATION 

[0001] This non-provisional application claims pnonty under 35 U.S.C. § 119(a) on Patent Application No. 2018- 150050 filed in Japan on Aug. 9, 2018, the entire contents of which are hereby incorporated by reference. 

[0002] This invention relates to a resist composition and a pattern forming process. 

[0003] To meet the demand for higher integration density and operating speed of LS Is, the effort to reduce the pattern rule is in rapid progress. In particular, the enlargement of the logic memory market to comply with the wide-spread use of smart phones drives forward the miniaturization technology. As the advanced miniaturization technology, manufacturing of microelectronic devices at the 10-nm node by double patterning of the ArF immersion lithography has been imple› mented in a mass scale. Manufacturing of 7-nm node devices as the next generation by the double patterning technology is approaching to the verge of high-volume application. The candidate for 5-nm node devices as the next generation but one is EUV lithography. 

[0004] As the pattern feature size is reduced, approaching to the diffraction limit of light, light contrast lowers. In the case of positive resist film, a lowering of light contrast leads to reductions of resolution and focus margin of hole and trench patterns. For mitigating the influence of reduced resolution of resist pattern due to a lowering of light con› trast, an attempt is made to enhance the dissolution contrast of resist film. 

[0005] Chemically amplified resist compositions compris› ing an acid generator capable of generating an acid upon exposure to light or EB include chemically amplified posi› tive resist compositions wherein deprotection reaction takes place under the action of acid and chemically amplified negative resist compositions wherein polarity switch or crosslinking reaction takes place under the action of acid. Quenchers are often added to these resist compositions for the purpose of controlling the diffusion of the acid to unexposed region to improve the contrast. The addition of quenchers is fully effective to this purpose. A number of amine quenchers were proposed as disclosed in Patent Documents 1 to 3. 

[0006] With respect to the acid labile group used in methacrylate polymers for the ArF lithography resist mate› rial, deprotection reaction takes place when a photoacid generator capable of generating a sulfonic acid having fluorine substituted at a-position (referred to "a-fluorinated sulfonic acid") is used, but not when an acid generator capable of generating a sulfonic acid not having fluorine substituted at a-position (referred to "a-non-fluorinated sulfonic acid") or carboxylic acid is used. If a sulfonium or iodonium salt capable of generating an a-fluorinated sulfo› nic acid is combined with a sulfonium or iodonium salt capable of generating an a-non-fluorinated sulfonic acid, the sulfonium or iodonium salt capable of generating an a-non› fluorinated sulfonic acid undergoes ion exchange with the 

## TECHNICAL FIELD 

## BACKGROUND ART 

a-fluorinated sulfonic acid. Through the ion exchange, the a-fluorinated sulfonic acid thus generated by light exposure is converted back to the sulfonium or iodonium salt while the sulfonium or iodonium salt of an a-non-fluorinated sulfonic acid or carboxylic acid functions as a quencher. Patent Document 4 discloses a resist composition compris› ing a sulfonium or iodonium salt capable of generating carboxylic acid as a quencher. 

[0007] Patent Document 5 discloses a resist composition comprising an iodized aniline as a quencher. The aniline has a low basicity which is insufficient to suppress acid diffu› s10n. 

[0008] Sulfonium and iodonium salt type quenchers are photo-decomposable like photoacid generators. That is, the amount of quencher in the exposed region is reduced. Since acid is generated in the exposed region, the reduced amount of quencher leads to a relatively increased concentration of acid and hence, an improved contrast. However, the acid diffusion in the exposed region is not suppressed, indicating the difficulty of acid diffusion control. 

[0009] Patent Document 1: JP-A 2001-194776 

[0010] Patent Document 2: JP-A 2002-226470 

[0011] Patent Document 3: JP-A 2002-363148 

[0012] Patent Document 4: WO 2008/066011 

[0013] Patent Document 5: JP-A 2018-097356 

[0014] For the acid-catalyzed chemically amplified resist, it is desired to develop a quencher capable of reducing the LWR of line patterns or the CDU of hole patterns and improving sensitivity. 

[0015] An object of the invention is to provide a resist composition which exhibits a high sensitivity and a reduced LWR or improved CDU, independent of whether it is of positive tone or negative tone; and a pattern forming process using the same. 

[0016] The inventors have found that using an amine compound having an iodine-substituted aromatic ring (also referred to as iodized aromatic ring-containing amine com› pound, hereinafter) as the quencher, a resist material having a reduced LWR, improved CDU, high contrast, improved resolution, and wide process margin is obtainable. 

[0017] In one aspect, the invention provides a resist com› position comprising a base polymer and a quencher, the quencher being an amine compound having an iodine› substituted aromatic ring bonded to the nitrogen atom via a C$_{1 }$-C$_{20 }$ divalent hydrocarbon group which may contain at least one moiety selected from ester bond and ether bond. [0018] Specifically, the amine compound has the formula (A). 

<img src='content_image/915690.jpg'>

## DISCLOSURE OF INVENTION 

## CITATION LIST 

