Packaging of multiple active optical devices

Abstract

A cost effective 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 with fine pitch and high accuracy “after-bonding” alignment to the alignment features on substrate and/or to other elements of the hybrid circuit. A Flip-Chip Bonder equipped with high precision Bonding Arm and optical and mechanical system, heated substrate chuck and heated pick-up tool may be used both for alignment and thermal bonding of active component dies to corresponding bonding pads on the common substrate 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 (Au—Sn) solder at the bond of previously attached die does not melt and, consequently, the alignment is not compromised.

What is claimed is:  
     
         1 . An apparatus, comprising: 
 an active optoelectronic device die bonded to a substrate using a zeta-phase composition of a gold-tin (Au—Sn) solder.    
     
     
         2 . The apparatus of  claim 1 , wherein the zeta-phase composition of Au—Sn solder comprises an 88-90% wt/12-10% wt Au—Sn solder composition.  
     
     
         3 . The apparatus of  claim 1 , wherein the active optoelectronic device die comprises an optical modulator die.  
     
     
         4 . The apparatus of  claim 3 , wherein the substrate comprises a silicon substrate.  
     
     
         5 . An apparatus, comprising: 
 an active optoelectronic device die bonded to a substrate using a gold-tin (Au—Sn) solder composition whose melting temperature is greater than the eutectic temperature of eutectic Au—Sn solder, the die further comprising a gold-layered die bonding pad and a gold-layered substrate bonding pad disposed in a well of the substrate.    
     
     
         6 . The apparatus of  claim 5 , wherein the solder composition whose melting temperature is greater than the eutectic temperature of eutectic Au—Sn solder comprises an Au—Sn solder composition whose melting temperature is greater than approximately two hundred seventy-eight degrees Centigrade.  
     
     
         7 . The apparatus of  claim 5 , wherein the active optoelectronic device die comprises light emitting diode die.  
     
     
         8 . The apparatus of  claim 7 , wherein the substrate comprises a silicon substrate having wire-bonding pads routed to either side of the substrate.  
     
     
         9 . A system, comprising: 
 an active optoelectronic device die bonded to a substrate using a zeta-phase composition of a gold-tin (Au—Sn) solder; and    a waveguide disposed on the substrate and operatively aligned to the active optoelectronic device die.    
     
     
         10 . The system of  claim 9 , further comprising: 
 a second active device die bonded to the substrate using a zeta-phase composition of a gold-tin (Au—Sn) solder; and    a second waveguide disposed on the substrate and operatively coupled to receive light from the second active optoelectronic device die.    
     
     
         11 . The system of  claim 10 , further comprising a light combiner disposed on the substrate and operatively coupled to receive and combine light from the first and the second active device dies.  
     
     
         12 . The system of  claim 11 , further comprising a third waveguide disposed on the substrate and operatively coupled to receive light from the light combiner.  
     
     
         13 . The system of  claim 11 , wherein the first and second active optoelectronic devices comprise a first and a second laser die having a first and a second operating wavelength, respectively.  
     
     
         14 . The system of  claim 10 , further comprising a demultiplexer disposed on the substrate and operatively coupled to separate and transmit light having a first wavelength to the first active optoelectronic device die and light having a second wavelength to the second active optoelectronic device die.