Consideration of Burn-In acceleration and effective screening procedure in latest System LSI

Abstract

An effective procedure to determine the burn-in acceleration factors for latest system LSI (Large Scale Integration) with 90 nm and 65 nm technology are discussed in this paper. The relationship among yield, defect density, and reliability, is well known and well documented for defect mechanisms. In particular, it is important to determine the suitable acceleration factors for temperature and voltage to estimate the exact burn-in conditions needed to screen these defects. The approach in this paper is found to be useful for recent Cu-processes which are difficult to control from a defectivity standpoint. Performing an evaluation with test vehicles of from 130 nm to 65 nm technology, the following acceleration factors were obtained, Ea>0.9 ev and gamma(Gamma)>-5.85. In addition, it was determined that a lower defect density gave a lower Weibull shape parameter. As a result of failure analysis, it is found that the main failures in these technologies were caused by particles, and their Weibull shape parameter ldquobetardquo was changed depending of the related defect density. These factors can be applied for an immature time period where the process and products have failure mechanisms dominated by defects. Thus, an effective Burn-In is possible with classification from the standpoint of defect density, even from a period of technology immaturity.