Patent ID: 7927697

Claim:
A double-sided pressure-sensitive adhesive tape or sheet for wiring circuit board, comprising a pressure-sensitive adhesive layer formed by a pressure-sensitive adhesive composition containing an acrylic polymer and a chain transfer substance, the chain transfer substance being a tackifier resin containing a phenolic hydroxyl group, in a proportion of from 5 to 45 parts by weight with respect to 100 parts by weight of the acrylic polymer, wherein said pressure-sensitive adhesive layer has characteristics in which a gel fraction in the initial stage is from 40 to 70% by weight, and a difference between a gel fraction after a solder reflow step and the gel fraction in the initial stage is 10 or less, said solder reflow step satisfying the following heat treatment conditions: (a) a surface temperature of said pressure-sensitive adhesive tape or sheet reaches 175±10° C. within 130 to 180 seconds after start of the solder reflow step for said pressure-sensitive adhesive tape or sheet; (b) the surface temperature of said pressure-sensitive adhesive tape or sheet reaches 230±10° C. within 200 to 250 seconds after start of the solder reflow step for said pressure-sensitive adhesive tape or sheet; (c) the surface temperature of said pressure-sensitive adhesive tape or sheet reaches 255±15° C. within 260 to 300 seconds after start of the solder reflow step for said pressure-sensitive adhesive tape or sheet; and (d) the solder reflow step finishes within 370 seconds after start of the solder reflow step for said pressure-sensitive adhesive tape or sheet.