Submount of semiconductor laser diode, method of manufacturing the same, and semiconductor laser diode assembly using the submount

Abstract

Provided is a submount flip-chip bonded to a semiconductor laser diode chip with stepped first and second electrodes. The submount includes a substrate having first and second surfaces which are separated by a step height corresponding to a height difference between the first and second electrodes; first and second metal layers being formed to the same thickness on the first and second surfaces, respectively; and first and second solder layers being formed to the same thickness on the first and second metal layers, respectively, and being bonded to the first and second electrodes, respectively.

1 . A method of manufacturing a submount flip-chip bonded to a semiconductor laser diode chip with stepped first and second electrodes, the method comprising: 
 (a) etching a substrate to form first and second surfaces that are separated by a step height corresponding to a height difference between the first and second electrodes;    (b) depositing a metal on the first and second surfaces to form first and second metal layers of the same thickness; and    (c) depositing a solder on the first and second metal layers to form first and second solder layers of the same thickness to be respectively bonded to the first and second electrodes.    
     
     
         2 . The method according to  claim 1 , wherein in step (a), the substrate is dry etched.  
     
     
         3 . The method according to  claim 1 , wherein the substrate is made of one of AlN, SiC, GaN, and an insulating material having a heat transfer coefficient corresponding to that of one of AlN, SiC, and GaN.  
     
     
         4 . The method according to  claim 1 , wherein the first and second metal layers are made of an alloy of two or more selected from the group consisting of Cr, Ti, Pt, and Au.  
     
     
         5 . The method according to  claim 1 , wherein the first and second solder layers are made of an alloy of two or more selected from the group consisting of Cr, Ti, Pt, Au, Mo, and Sn.