Provided are a semiconductor surface protecting method and surface protecting sheet employing a material having adequate conformability for irregularities on semiconductor wafer circuit sides and sufficient rigidity as a support during grinding, and which does not become fluid with repeated temperature increases. Also provided is a surface protecting sheet for protection of the circuit side in the step of back side grinding of a semiconductor wafer, the surface protecting sheet having a polymeric film material with a surface protecting layer thereon that may become fluid upon heating and which hardens upon exposure to radiation or upon heating.