Investigation on Thermal Resistance of Cracked AlInGaP Die Substrateand In-line Die Crack Testing Method

Abstract

This paper has demonstrated correlation between cracks at an LED germanium (Ge) substrate to its thermal resistance. The finding shows, the Rth value, increases with the crack severity. Further analysis, shows the presence of many cracks inside the Ge-substrate, that were die attach at bond-force 140 gF as compared to at 60 gF. This impedes the heat flow and thus cause increase in Rth value. A unique test apparatus that uses Temperature Sensitive Parameters (TSP) method was designed to capture the voltage variation of cracked-dice. The results proofed, this apparatus successfully detects cracked-dice without compromising the testing throughput time.