Study of adhesion of crystals to a temporary carrier when using polyimide varnish as an adhesive

In wafer-level packaging technologies, polyimide can be used not only as a dielectric, but also at the same time play the role of an adhesive for attaching crystals. In this case, the crystals are mounted on liquid varnish, which then undergoes imidization. The work shows that the adhesion of crystals to polyimide can be up to 695.3 g/mm2 and depends both on the type of polyimide and on the exposure time of the varnish after application.