7  4  -continued  62  US 8,962,233 B2  61  (pl) to (pV). Structures resulting from replacement of a  hydrogen atom of a carboxylic acid group or sulfonic acid  group with any of the structures of the general formulae (pl)  to (p V) are preferred.  As preferred repeating units having any of the alkali- soluble groups protected by the structures of the general  formulae (pl) to (p V), there can be mentioned those of general  formula (pA) below.  A represents any one or a combination of two or more  groups selected from the group consisting of a single bond, an  alkylene group, an ether group, a thioether group, a carbonyl  group, an ester group, an amido group, a sulfonamido group,  a urethane group and a urea group. A single bond is preferred.  Ppl represents any of the groups of the above general  formulae (pl) to (p V).  The repeating units of the general formula (pA) are most  preferably those derived from a 2-alkyl-2-adamantyl(meth)  acrylate and a dialkyl(l-adamantyl)methyl(meth)acrylate.  Specific examples of the repeating units of the general  formula (pA) will be shown below.  2  (pA)  R  #  A710-Rp1  0 