Direct bonding of micromachined silicon wafers for laser diode heat exchanger applications

A novel application of silicon direct-thermal-wafer bonding is demonstrated using micromachined wafers. Two (110) Si wafers are patterned and micromachined using wet chemistry. The prepared wafers are cleaned, leaving only native chemical oxides on the Si surfaces. After the cleaning steps, the wafers are thermally bonded without electrostatic pressure. The points of bonded contact are 410 mu m*25 mu m. Hydraulic pressure testing on the bonded wafers has substantiated a bond strength comparable to contiguous SiO2. The final structure is intended as a micromachined heat exchanger for cooling laser diodes.