Oriented design of wafer-level stacking structures to enhance reliability of laser debonding of thin devices

Abstract

The laser debonding process in advanced packaging has become a key technology for the debonding of ultra-thin wafers. However, improving the reliability of debonding and efficient removal of adhesive residues from thin and brittle devices remains challenging. Here, we fabricated bonding pairs formed by inorganic responsive layer, thermal buffer layer, and adhesive layer based on a structural design-oriented strategy. Experimental results showed that the thinned device wafers did not show any damage after laser debonding, and the residual adhesive film could be easily torn off. The response layer (a-Si:H) with high temperature resistance and corrosion resistance has strong photosensitivity under the action of ultraviolet laser with a wavelength of 355 nm, and rapidly decomposes to release H2 and polysilicon nanoparticles. The thermal buffer layer is primarily intended to block the heat flow and compensate internal stress. The adhesive layer acts both as an adhesive during temporary bonding and as a barrier to laser-induced gas shock waves and plasma etching of device layers during debonding. This rational structural design contributes to improves the reliability of the laser debonding process and shows great potential for application in the next generation of thin device debonding.