Laser releasable temporary bond/de-bond materials for next 3D packages

Laser releasable temporary bond/de-bond (TBDB) materials we recently developed are described. Our laser TBDB materials are composed of two parts: release layer materials and adhesive layer materials. Release layer materials, which are essential for laser TBDB process, are designed to absorb UV laser such as 308 or 355 nm in wavelength. The de-bonding mechanism using such UV laser is based on direct decomposition of TBDB materials by photonic cleavage. This is one of the advantages compared to that of IR laser release system which decomposes TBDB materials by thermal degradation and may sometimes cause thermal damage for devices. The release layer materials developed have very high UV absorption property, which contributes to reduce laser irradiation energy and shorten laser release process time. Adhesive layer materials, which are required to hold device wafers correctly on rigid support wafers, are also developed. They shows good adhesion property against each materials which are expected to contact in actual use. Excellent thermal and chemical stability of the materials are also described.