US 2019/0196326 Al  28  Jun.27,2019  -continued  4  7  9  2  1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an  alkoxy group (having 1 to 4 carbon atoms), a carboxy group,  and an alkoxycarbonyl group (having 2 to 6 carbon atoms),  and a group having 8 or less carbon atoms is preferable.  [0207]  The content of the sum of the repeating units  having acid-decomposable groups is preferably 20 to 90 mo!  %, more preferably 25 to 85 mo! %, and even more  preferably 30 to 80 mo!  % with respect to the all repeating  units in the resin (A).  [0208]  Specific examples of the repeating unit having an  acid-decomposable group are provided below, but the pres› ent invention is not limited thereto.  [0209]  In the specific examples, Rx and Xa$_{1 }$ each inde› pendently represent a hydrogen atom,  CH$_{3}$ ,  CF $_{3}$ ,  or  CH$_{2}$0H.  Rxa and Rxb each represent an alkyl group having 1 to 4  carbon atoms. Z represents a substituent including a polar  group, and in a case where there are a plurality of Z’s, Z’s  each independently represent a substituent including a polar  group. p represents 0 or a positive integer. Examples of the  substituent including a polar group represented by Z include  a linear or branched alkyl group having a hydroxyl group, a  cyano group, an amino group, an alkylamido group, or a  sulfonamide group, or a cycloalkyl group, and the substitu› ent is preferably an alkyl group having a hydroxyl group.  The branched alkyl group is more preferably an isopropyl  group.  Rx  I  --+CH2-C+- j  O=C  Rxa  I  0-+---<  (Z)p  Rxa  Rxb 