Preparation of reversible thermosets and their application in temporary adhesive for thin wafer handling

Adhesive materials are the key component in the whole temporary bonding/debonding process for thin wafer handling. In this study, a reversible thermoset was synthesized by polycondensation between methyl diamine and aldehydes and was used as the basic resin for temporary adhesive. The use of thermoset endows the adhesive with excellent thermal and chemical stabilities. Moreover, the thermoset can be depolymerized to recover the monomers at a low pH and thus the adhesion was switched off by soaking in strong acids. A perforated glass wafer was bonded with a silicon wafer using the thermoset-based adhesive. It was shown the bonded pair can be separated after soaking in acids. It was further demonstrated that the debonding efficiency can be increased by optimizing the distribution and diameter of the holes in the carrier.