ASSEMBLY OF ACTIVE OPTICAL DEVICES ON A SUBSTRATE

摘要

A method is provided for assembly of hybrid optoelectronic circuits requiring flip-chip bonding of multiple active optoelectronic devices onto common substrate or optical bench platform. Thermal bonding of active component dies to corresponding bonding pads on the common substrate is achieved using gold-tin (Au-Sn) solder disposed between die bonding pad and the corresponding substrate bonding pad. During bonding of the first die, tin (Sn) diffuses from a eutectic composition of gold-tin (Au-Sn) solder to (gold (Au) on) the die-bonding pad and/or (gold (Au) on) the substrate bonding-pad resulting in transformation of the Au-Sn eutectic composition to a zeta-phase composition having much higher melting temperature as compared to that of a eutectic composition. As bonding of one or more subsequent dies is performed at temperatures equal to or slightly higher than the melting temperature of a eutectic composition and significantly lower than the melting temperature of a zeta-phase composition, the gold-tin (Au­Sn) solder at the bond of previously attached die does not melt and, consequently, the alignment is not compromised.