on total units of the polymer more preferably b is from 2 to about 75 or 80 mole percent of total polymer units still more preferably b is from 5 or 10 to about 75 or 80 mole percent of total polymer units as discussed above resins used in resists of the invention also may contain a heteroalicyclic ring that is preferably fused to a polymer backbone the fused heterocyclic ring units contain one or more oxygen and or sulfur atoms by stating herein that a cyclic group is fused to a polymer backbone it is meant that two ring members of the cyclic group typically two adjacent carbon atoms of the cyclic group are also part of the polymer backbone such a fused ring can be provided by polymerizing a cyclic monomer that has an endocyclic double bond the oxygen and or sulfur atoms of the heteroalicyclic ring are preferably direct ring members bi radical linkages rather than e g a multiple bond group such as a keto or thioketo ring member also less preferred are groups that contain any such saturated groups such as a ketone or other carbonyl including ester lactone anhydride etc preferred oxygen ring polymer units will be free of other hetero atoms such as sulfur i e only oxygen and carbon ring members typically the oxygen ring unit will contain a single oxygen ring atom and may have one or more ring substituents as discussed above it has been found that such ring substituents can significantly enhance substrate.