Low temperature full wafer adhesive bonding of structured wafers

In this paper, we present a technology for void free low temperature full w afer adhesive bonding of structured wafers. Benzocyclobutene (BCB) is used as the intermediate bonding material. BCB bonds well with various materials and does not release significant amounts of byproducts during the curing p rocess. Thus void-free bond interfaces can be achieved. Cured BCB coatings have an excellent resistance to a variety of acids, alkalines and solvents and a high transparency for light across the visible spectrum, which makes it a good material for fluidic, optical and packaging applications. We demo nstrate the fabrication of fluidic structures and the embedding of protrudi ng surface structures. An important finding is that the pre-cured BCB coati ngs are extremely deformable and have a "liquid-like" behaviour during bond ing. (C) 2001 Elsevier Science B.V. All rights reserved.