Optimal Parameters on IRED Wire Bonding Process Capability : Power, Time

Abstract

LED / IRED had been widely used for a long time due to its low cost and low current characteristic. Also it is a mature process in Taiwan. There are many steps in LED package process, die mount, wire bond, encap…. and so on. But wire bonding is the most critical & important process due to reliability concern. In general speaking, pull tension test had been used to measure the bonding quality. Conventional repeatability and reproducibility studies involve multiple measurements of same specimen by multiple operators. All results base on the samples are non-destructed after test. This approach can’t be applied on pull tension test. As a result, within-sample variability become an issue. In this study, we selected 1 low variation material from 2 experimental groups and treat the variability comes from equipment. Comparing to normal pull tension test, equipment variation only take 17% of total variation. We can conclude that this measurement system is “ Fair “. On the other hand, one year process pull tension test data are collected and process capability index (CPL) is applied to find out the optimal range of parameters through “ Quadratic Smooth “ of “ Statistica “.