Heat-peelable adhesive sheet

Abstract

When a heat-peelable adhesive sheet is to be used, the heat-peelable adhesive sheet intended for a different work piece, a different step, or the like may be mistakenly used on occasion. For this reason, it is necessary to clearly confirm the heat-peelable adhesive sheet that can be used for a different work piece or a different step in order to prevent the occurrence of such an error. Further, in the case of a colorless, transparent heat-peelable adhesive sheet, it is difficult to confirm whether bonding onto the work piece has been accurately performed. Merely coloring the adhesive layer of a heat-peelable adhesive sheet is liable to contaminate and damage the electronic components in that metal ions originating from the coloring agent are deposited on the electronic components or other work piece surfaces. In order to resolve the foregoing problems, provided is a heat-peelable adhesive sheet characterized in that one or both surfaces of a substrate are provided with thermally expanding adhesive layer containing thermally expanding microspheres and a colorant, or one or both surfaces of a substrate are provided with a thermally expanding adhesive layer containing thermally expanding microspheres via a coloring intermediate layer, and in that the total light transmittance is at least 50%.

Description

technical field [0001] The present invention relates to a heat-peelable adhesive sheet. Background technique [0002] In processing such as dicing and back grinding of semiconductor wafers, processing such as cutting when manufacturing electronic parts, and processing such as optical parts, it is integrated by reliable adhesion to the workpiece. It is fixed on the processing machine by sandwiching the heat-peelable adhesive sheet, so that the processing can be carried out smoothly. [0003] When such a to-be-processed object is processed, the process of fixing a to-be-processed object to the adhesive layer of a heat release type adhesive sheet is required. [0004] In this step, an appropriate heat-peelable pressure-sensitive adhesive sheet is selected according to the type of workpiece. In this case, these heat-peelable pressure-sensitive adhesive sheets have in common that they are colorless and transparent sheets, and when the roll of the heat-peelable pressure-sensitiv...

AI Technical Summary

Problems solved by technology

Furthermore, as a result, heat-peelable PSA sheets of all product numbers were colored in the same way, and when heat-peelable PSA sheets were selected according to the workpiece, heat-peelable PSA sheets could not be distinguished

In addition, due to the absorption of infrared rays, the light transmittance of the heat-peelable adhesive sheet is reduced, and most of the light cannot pass through.

[0009] As shown in Patent Document 2, it is also known that a thermochromic microsphere pigment is contained in a heat-expandable adhesive layer of a heat-peelable adhesive sheet. Contained, so it is colorless and transparent before using the heat-peelable adhesive sheet before thermal expansion of the heat-expandable adhesive layer, so that the heat-peelable adhesive does not change according to the product number, etc. before using the heat-peelable adhesive sheet. The color of the agent layer

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