A radiation detackifiable adhesive composition comprising a (meth)acrylate copolymer including from about 85 wt. % to about 97.5 wt. % of a (meth)acrylate ester and from about 2.5 wt. % to about 15 wt. % of a copolymerizable carboxylate monomer and a multi-functional urethane acrylate oligomer combined with the (meth)acrylate copolymer to provide from about 25 parts to about 40 parts of the oligomer per 100 parts of the copolymer. The adhesive composition becomes progressively detackified during exposure to ultraviolet radiation. The present invention further provides a clear adhesive coated sheet for supporting a silicon wafer during manufacture of semiconductor microchips. The coated sheet comprises a transparent film substrate coated with a radiation detackifiable adhesive composition.