Thickness measurement of Si substrate with infrared laser of Optical Beam Induced Resistor Change (OBIRCH) in failure analysis

With scaling down and multi-metal-layer of semiconductor devices, it was very difficult to perform OBIRCH analysis from front side in failure analysis (FA). Meanwhile information to us. So, backside technique for FA was developed in microelectronics yield in recent years. As is known to all, we could obtain clearer infrared (IR) image from backside as Si substrate occur die crack in physical analysis. Thus, we must make sure die thickness in backside step. In this paper we firstly proposed one novel method of thickness measurement of Si substrate with IR laser of OBIRCH in FA lab. The principle of this method was presented theoretically in detail. And then some experiments were performed, and the results matched theoretical analysis well. Finally, we summarized the step of method and pointed out some notes for this method.