Adhesive wafer bonding for MEMS applications

Abstract

Low temperature wafer bonding is a powerful technique for MEMS/MOEMS devices fabrication and packaging. Among the low temperature processes adhesive bonding focuses a high technological interest. Adhesive wafer bonding is a bonding approach using an intermediate layer for bonding (e.g. glass, polymers, resists, polyimides). The main advantages of this method are: surface planarization, encapsulation of structures on the wafer surface, particle compensation and decrease of annealing temperature after bonding. This paper presents results on adhesive bonding using spin-on glass and Benzocyclobutene (BCB) from Dow Chemicals. The advantages of using adhesive bonding for MEMS applications will be illustrated by presenting a technology of fabricating GaAs-on-Si substrates (up to 150 mm diameter) and results on BCB bonding of Si wafers (200 mm diameter).

Wafer-level plasma activated bonding: new technology for MEMS fabrication

“…Developments were carried in two main directions: bonding substrates using intermediate layers [adhesive bonding using polymers intermediate layers (Dragoi et al 2003), eutectic bonding (Turner et al 2002), metal diffusion bonding (Tsau et al 2004)] and direct bonding methods using special surface preparation techniques (Dragoi and Lindner 2006). Direct (fusion) bonding is based on molecular bonds established between molecules from the two substrates' surfaces.…”

Metrology, Inspection, and Process Control in Micro‐Scales

“…SAM enables a nondestructive technique for reliability inspection of micromachined components. Cracks, delamination, voids, and stiction can be detected by SAM [64][65][66]. A lateral resolution of a few microns and depth of field of few millimeters can be obtained.…”

Adhesive wafer bonding with photosensitive polymers for MEMS fabrication

“…Various types of polymer materials were reported being used as bonding layers (Alexe et al 2000;Dragoi et al 2003;Matthias et al 2006). Independent of the polymer class, from wafer bonding perspective there are two main categories of polymer materials based on their behavior during bonding: one is represented by materials which become viscous and flow during bonding process while the second category is formed by materials which remain rigid after baking process and subsequently during bonding.…”