A Novel Bonding Architecture Based on AAO

Packaging is the most serious problem and challenge in MEMS device manufacturing, which costs 50-80 percent of the total cost (Bryzek, 1996). In this paper, Si-Au eutectic bonding, a packaging technology is researched based on Si-based anodized aluminum oxidation (AAO). In Si-Au bonding process, because of the different thermal expansion coefficients of Si and Au, the residual stress occurs in the bonding area even during the anneal process, which will result in the early failure in the life time. In order to improve the quality of Si-Au bonded wafer, a method which utilizes AAO film between Si and Au, is presented in this paper to release the residual stress of Si-Au bonded wafer during the anneal process due to the pores and the thin side wall of AAO. It can be seen from the test that the addition of AAO in Si-Au bonded wafer make the bonding strength of Si-Au eutectic bonded wafer increases from 1.78MPa to 3.03 MPa, but the broken zone of bonded wafer doesn't change, still takes place in Au layers.