Characterization of localized laser assisted eutectic bonds

An innovative bonding process for silicon and single crystal quartz has been developed and investigated using various material science characterization methods, such as TOF-SIMS, SEM, EDX and XRD. The bonding process combines the principles of laser transmission welding, eutectic bonding and bonding by localized heating. A focused laser beam (low power, max. 0.83 W) is transmitted through a quartz medium to intermediate layers of chromium, gold and tin at the silicon–quartz interface to provide localized heating and bonding. This bonding process is particularly suitable for bonding wafers containing temperature sensitive devices as it confines the temperature increase to a small area. Bond strength of over 15 MPa is comparable to most localized bonding schemes. This process provides a simple yet robust bonding solution with rapid processing time, selectivity of bonded area and corrosion resistant joints.