Cooling rate in diode laser bonding

Diode laser die bonding parameters were measured for the cases of slow cool and rapid cool die bonding processes. The thermal strain, solder composition and structure, thermal impedance, and bond strength of InP based diode lasers bonded to AlN chip carriers using pre-deposited Au-Sn solder were examined. Relative to the rapid cool process, the slow cool process was found on average: to induce greater strain in the laser chips; to exhibit a larger thermal impedance in the die bonds; to produce a rougher solder structure; and, to promote alloying of the solder material and chip carrier metallization.