Alignment of Silicon wafers for 3D Packaging

Abstract

Wafer level self-alignment is investigated with a Self assembled monolayer (SAM) deposition, SAM termination modification, friction dry and capillary alignment forces. SAMs are deposited on oxide layer, and characterized by ellipsometry and contact angle. Vinyl-terminated SAMs are oxidized to carboxyl-termination, which changes the wetting characteristics. Measurements for characterizing the layers are presented. The relative surface energies can also be estimated. From these characteristics it will be shown how surface energy is modified for the purpose of generating surface energy gradients in use with a self-alignment process. Self-alignment is observed using capillary forces, and exhibits a reasonable capture range. The self-alignment masks are used to increase this force and will be discussed.