| 摘要 |
PROBLEM TO BE SOLVED: To provide a heating release-type adhesive sheet enabling adhesive strength to be decreased to a defined level even in the case that many cut grooves have been formed accompanying the miniaturization of electronic parts. SOLUTION: This heating release-type adhesive sheet has a superimposed layer made of two or more thermally expandable layers each containing thermally expandable microspheres on at least one side of a substrate 1. The thermally expandable layer 4 located in the longest distance from the substrate 1 contains thermally expandable microspheres having the highest thermal expansion-starting temperature and shows stickiness. A thermally expandable layer 3 containing thermally expandable microspheres having a lower thermal expansion-starting temperature than the mirospheres in the layer 4 exists between the layer 4 and the substrate 1. The inside thermally expandable layer capable of expanding at a lower temperature expands to fill in the cut grooves formed on the adhesive thermally expandable layer before the thermally expandable layer adhesively holding electronic parts, etc., expands, and then the adhesive thermally expandable layer expands. The deformation due to the expansion is efficiently utilized for the reduction of adhesive strength and can stably decrease adhesive strength.
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