Feb.4,2021  33  US 2021/0033971 Al  (AL-3)-22  -continued  [0097]  In formula (AL-3)-22,  RA  is as defined above.  RLc1 2  and  RLc1 3  are each independently a C$_{1 }$-C$_{10 }$hydrocar› byl group, or  RLc1 2  and  RLc1 3 ,  taken together, may form an  aliphatic ring with the carbon atom to which they are  attached.  RLc1 4  is furandiyl, tetrahydrofurandiyl or oxanor- [0096]  Examples of the monomer from which the recur› ring units having an acid labile group of formula (AL-3) are  derived include (meth)acrylates having a furandiyl, tetrahy› drofurandiyl or oxanorbornanediyl group as represented by  the following formula (AL-3)-22. 