Patent ID: 7968039

Claim:
A method of producing a pressure-sensitive adhesive sheet that comprises at least a substrate and a base pressure-sensitive adhesive layer, the method comprising: directly irradiating a pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer with a CO 2 laser and forming through-holes as precise, uniform through-holes in the pressure-sensitive adhesive sheet, the CO 2 laser having a pulse width of from 1 to 140 μsec, a pulse energy at each processing point of from 0.01 to 3.0 mJ, and a beam spot diameter at each processing point of from 30 to 160 μm, wherein a diameter of the through-holes is smaller on the substrate side than on the base pressure-sensitive adhesive layer side, and a diameter of the through-holes in the substrate and the base pressure-sensitive adhesive layer is from 0.1 to 200 μm and a diameter at a surface of the substrate is from 0.1 to 42 μm at a hole density of from 30 to 50,000 per 100 cm 2 .