SUPPORTING PAD

摘要

A supporting pad is provided which has a supporting face with heightened flatness precision and can improve the in-plane evenness of an object to be polished.  The supporting pad (10) includes a urethane sheet (2).  The urethane sheet (2) has been formed by the wet solidification method and has a supporting face (Sh) for supporting an object to be polished.  The urethane sheet (2) has a skin layer (2a) of a microporous structure, and has many cells (3) formed on the inner side of the skin layer (2a) and having such a size that the cells (3) extend over almost the whole thickness of the urethane sheet.  In the urethane sheet (2), the bottoms of the cells (3) are located in the range of from the back side (Sr) to a depth of 0.1t therefrom, provided that t is the thickness of the urethane sheet (2).  In a lower layer part (Pr) sandwiched between the section which is located 0.1t inward from the back side (Sr) and is parallel to the back side (Sr) and the section which is located 0.4t inward from the back side (Sr) and is parallel to the back side (Sr), the urethane sheet has a porosity, concerning the cells (3), regulated to 75-95%.  In polishing, the urethane sheet (2) shows an increased compressive deformation in the lower layer part (Pr).