Method of processing workpiece and resin sheet unit

A method of processing a workpiece with devices formed on a face side thereof by polishing a reverse side of the workpiece, comprising:

• sticking an adhesive layer side of a resin sheet having a layered structure that includes an adhesive layer and a base material layer, to a support base;
• before or after sticking the adhesive layer side, forming surface irregularities on a face side of the base material layer that is opposite the adhesive layer;
• after sticking the adhesive layer side and forming the surface irregularities, placing the face side of the workpiece and the face side of the base material layer in facing relation to each other, and pressing the workpiece against the resin sheet or pressing the resin sheet against the workpiece, thereby bringing the workpiece into intimate contact with the resin sheet to fix the workpiece to the resin sheet, thereby forming a workpiece unit that includes the workpiece, the resin sheet, and the support base;
• placing the workpiece unit on a holding surface of a rotatable chuck table such that a surface of the support base is held by the holding surface of the rotatable chuck table;
• and
• after holding the surface of the support base, polishing the reverse side of the workpiece with a polishing pad disposed in facing relation to the holding surface.

A resin sheet unit for fixing a workpiece in intimate contact therewith, comprising:

• a resin sheet having a layered structure that includes an adhesive layer and a base material layer, with surface irregularities formed on a face side of the base material layer that is opposite the adhesive layer, the surface irregularities being defined by grooves in the face side of the base material layer and remaining portions of the face side of the base material layer;
• and
• a support base to which an adhesive layer side of the resin sheet is stuck,
• wherein the resin sheet unit fixes the workpiece to the support base by placing the face side of the workpiece and the face side of the base material layer in facing relation to each other and bringing the face side of the workpiece into intimate contact with the face side of the base material layer on which the surface irregularities are formed,
• wherein the grooves in the base material layer do not extend completely through the resin sheet.