Application of laser deprocessing technique in PFA on chemical over-etched on bond-pad issue

Abstract

With technology scaling of semiconductor devices and further growth of the integrated circuit (IC)11Integrated Circuit (IC). design and function complexity, the package size has shrank down proportionally too. Hence, flip-chip solder bump mounting is the current semiconductor devices trend to replace the wire bonding technology.When come to PFA22Physical Failure Analysis (PFA). on the flip-chip devices with solder bump, wet etch for solder bump removal is an essential method. Upon using wet etch methodology; it is very dependent on etching timing and the chemical aggressiveness to get a good removal result for the solder bump. If there is an excessive period in etching or chemical reacts too aggressively, chemical over-etched on bond pad will occur. It is very unfavorable for FA33Failure Analysis (FA). engineer to perform subsequent reverse engineering on the bond pad over-etched device.In this paper, the application of laser deprocessing technique is proposed to solve the bond pad over-etched issue. This proposed technique is a quick and reversal way in deprocessing technique for defect identification in PFA.