Wafer bonding for microsystems technologies

In microsystems technologies, frequently complex structures consisting of structured or plain silicon or other wafers have to be joined to one mechanically stable configuration. In many cases, wafer bonding, also termed fusion bonding, allows to achieve this objective. The present overview will introduce the different requirements surfaces have to fulfill for successful bonding especially in the case of silicon wafers. Special emphasis is put on understanding the atomistic reactions at the bonding interface. This understanding has allowed the development of a simple low temperature bonding approach which allows to reach high bonding energies at temperatures as low as 150 degrees C. Implications for pressure sensors will be discussed as well as various thinning approaches and bonding of dissimilar materials. (C) 1999 Elsevier Science S.A. All rights reserved.