Pressure-sensitive adhesive for wafer grinding and preparation method thereof

Abstract

The invention discloses a pressure-sensitive adhesive for wafer grinding and a preparation method thereof. The adhesive comprises a plastic base material, an adhesive layer coated on the base plastic material, and a release film which covers the adhesive layer. The preparation method of the pressure-sensitive adhesive comprises the following steps of: A) preparing a prepolymer; B) preparing an adhesive; C) preparing an adhesive tape. Compared with the prior art, the preparation method has the advantages that the dose and addition way of an initiating agent as well as the polymerizing temperature are controlled to realize the maximum molecular weight as well as high cohesive strength, and the problems of relatively high peeling strength and small shearing strength of the traditional pressure-sensitive adhesive are solved. In addition, a hard monomer added brings the pressure-sensitive adhesive with high shearing strength, and the demand on wafer grinding is met. The pressure-sensitive adhesive for wafer grinding is different from other adhesive tapes for wafer grinding in that a silane coupling agent bringing water resistance is directly polymerized onto a polymer molecular chain, instead of being directly added. Therefore, the migration of micromolecule in storage process is avoided, and the resulting influence to the effect or the resulting residue on a wafer is removed.

Description

technical field [0001] The invention relates to a pressure-sensitive adhesive, in particular to a pressure-sensitive adhesive coated on a plastic base material for fixing the wafer when thinning and protecting the front of the wafer from contamination. The pressure-sensitive adhesive is acrylic resin, It also contains a certain amount of photocurable acrylate double bonds. Before photocuring, this adhesive has good adhesion to wafers with various roughnesses. When irradiated with ultraviolet light, the adhesion decreases rapidly. There is even little to no adhesion, making wafers easy to pick up. Background technique [0002] Usually, before integrated circuit packaging, two or more layers of chips are stacked together for system packaging, which requires the wafer to be thinned to 150um or even below 150um. Since the back of the wafer has no practical effect, it can The excess matrix material on the back of the wafer is removed to a certain thickness. This process is call...

AI Technical Summary

Problems solved by technology

[0005] At the same time, during the back sanding process, heat will be generated, and this heat will be transferred to the adhesive layer of the tape, causing the temperature of the adhesive layer to rise. The adhesive layer of ordinary tape is easy to soften due to heating, and the shear strength decreases, which causes the wafer to move.