The effect of laser irradiation on peel strength of temporary adhesives for wafer bonding

Thin silicon wafers are usually used for many devices and electronic fabrication development. But handling thin wafers are not easy since thin wafers may lose the supporting strength and crack. Using adhesives is the one of the possible solutions for thin wafer handling, and how to synthesize adhesives materials and investigate debonding behaviors for temporary bonding and debonding are an important research. In this work, laser irradiation is considered for debonding temporary adhesives in a 3D multi-chip package process because of its very fast debonding time about few seconds and irradiation stability than thermal or chemical debonding. The thermal curable adhesives were fast cured on high temperature by the laser irradiation. The emphasis is the choice of the specific laser process parameters such as the out-focusing length, the line spacing, and the scan speed. The surface morphology with various sets of these parameters is examined by optical microscopy. Also, peel strength before/after the laser irradiation is investigated. Based on this study, suitable process parameters and conditions are proposed for clean surface of silicon wafers and lower peel strength for easy debonding.