US 10,921,710 B2  115  116  TABLE 7-continued  2-7  2-8  2-9  2-10  2-11  2-12  2-13  2-14  2-15  2-16  2-17  2-18  2-19  2-20  2-21  2-22  2-23  2-24  2-25  2-26  2-27  2-28  2-29  CD  CDU  CD  CDU  L\.PPD  Resist  (nm)  (30, nm)  (nm)  (30, nm)  CD  composition  @PPD Oh  @PPD Oh @PPD 6h  @PPD 6h (nm)  R-31  47.5  5.6  R-32  50.9  6.7  R-33  50.7  6.8  R-34  51.9  5.9  R-35  52.3  6.1  R-36  51.4  6.3  R-37  52.1  6.2  R-38  50.8  5.8  R-39  50.6  6.1  R-40  51.2  6.2  R-41  50.2  5.9  R-42  50.4  6.2  R-43  51.6  6.1  R-44  51.8  5.8  R-45  50.3  6.0  R-46  49.8  5.8  R-47  52.4  5.9  R-48  52.6  6.1  R-49  50.1  6.1  R-50  52.1  6.2  R-51  50.8  6.0  R-52  50.7  5.8  R-53  49.7  6.1  42.1  44.8  45.1  46.8  46.1  47.2  47.5  46.5  45.5  46.8  45.9  46.2  45.8  46.8  46.1  45.1  44.2  45.9  46.0  45.6  46.5  46.1  45.2  5.8  6.9  6.9  6.2  6.5  6.3  6.4  5.9  6.5  6.6  6.4  6.3  6.5  6.9  6.7  6.5  6.9  6.7  6.4  6.6  6.7  6.2  6.3  5.4  6.1  5.6  5.1  6.2  4.2  4.6  4.3  5.1  4.4  4.3  4.2  5.8  5.0  4.2  4.7  8.2  7.8  4.1  6.5  4.3  4.6  4.5  It  is evident from Tables 4 to 7 that the resist compositions  within the scope of the invention show improved DOF and  CDU and reduced CD shrinkage amounts by PPD (small CD  changes), as compared with well-known resist composi› tions.  Japanese Patent Application No. 2017-148008 is incor› porated herein by reference.  wherein  RA  is hydrogen or methyl, R 1  is a C$_{1}$-C$_{10 }$ straight,  branched or cyclic divalent hydrocarbon group in which at  least one carbon atom may be substituted by an ether or  carbonyl moiety,  Although  some  preferred  embodiments  have  been  described, many modifications and variations may be made  thereto in light of the above teachings.  It  is therefore to be  understood that the invention may be practiced otherwise  than as specifically described without departing from the  scope of the appended claims.  The invention claimed is:  wherein  RA  is as defined above and X is an acid labile group,  (1)  (3)  (4)  (2)  +to  $^{0 }$\ $_{X }$ (A)  a base resin consisting of recurring units having the  formula ( 1) shown below and recurring units having an  acid labile group having the formula (2) shown below,  and optionally at least one recurring unit selected from  the group consisting of recurring units having the  formulae (3) to (5) shown below,  (B) a photoacid generator consisting of a compound  having the formula (B-2) shown below, and  (C) a solvent,  1.  A  resist composition comprising: 