US 10,162,262 B2  38  37  -continued  Monomers containing an acid labile group other than the  foregoing are exemplified in U.S. Pat. No. 9,335,633 (JP-A  2015-166833, paragraphs [0061 ]-[0085]).  The base resin may further comprise recurring units of at  least one type selected from the formulae (cl), (c2) and (c3),  which are simply referred to as units (cl), (c2) and (c3).  (cl)  (c2)  R3  R3  R3  ~o ~o OH~o  O'+c6  0  R3  R3  ~o OH ~o  &6  0  R3  R3  ~o oM, ~o  +c6  0  MeO  R3  R3  ~o oM, ~o  00  0  R3  R3  ~o oA, ~o  +c6  0  R3  R3  ~o OA, ~o  &6  0  -continued  R101  I  +s-R 108  I  R109 