Patent ID: 7564119

Claim:
An adhesive sheet for laser dicing used for dicing a workpiece into individual chips by forming a reformed region inside the workpiece by light absorption ablation of laser beam, wherein the adhesive sheet has at least an adhesive layer on one side of a base material, wherein the base material has a surface having an arithmetic average height Ra of 0.4-0.9 μm, wherein said adhesive sheet is prepared by: disposing a separator on the adhesive layer to form a laminated sheet; taking up the laminated sheet in roll; heating the rolled laminated sheet at a temperature of 30 to 60° C. for 12 to 100 hours; and said adhesive sheet is cut from said rolled laminated sheet, wherein the surface of the base material that does not contact the adhesive layer is free from convex parts that have a height (h) of 1 μm or more over a width (W) of 20 mm or less, and concave parts that have a depth (d) of 1 μm or more over a width (W) of 20 mm or less, and wherein said separator comprises a surface not contacting with the adhesive layer that has an arithmetic average height Ra of 0.2 to 2 μm.