The Technical Study On Assebmly Defects And Final Test Of MOSFET

MOSFET is one of the most important discrete devices, which is playing irreplaceable function in many areas. The dissertation is going to study the characteristics of assembly defects in final test of MOSFET to improve the final test process, and so the quality could be elevated to meet the customer's growing demands on quality.The assembly of MOSFET is consisted of five main processes, which are wafer sawing, die attach, wire bond, molding, trim and form. Each process has some major defects impacting the passing yield of final test and the quality of products. The study of the dissertation will focus on studying the characteristics of each defect type in final test. Based on the conclusion of the study, current final test process will be synthetically improved at three aspects. First, define the methodology of setting the upper and low limit of test items and it could enhance the ability of screening out defects. Second, bin sort the defects by assembly defect corresponding to test data, so the failure mode could be fairly correctly concluded by bin result. Third, improve the yield management and it's for making up the insufficiency of the testability of test program to guarantee the quality of the finished products.By applying the study result and improvement methodology, the quality of finished goods and the passing yield could be enhanced. In SSU2N60B, yield is almost 1% higher than six month ago, quality test failures and customer complaints are obviously reduced too.