In The Wafer Test Slaughter (overkill) Judgment And Handling By Mistake

Wafer probe is an important proccess of IC manufacture.As the fast development of IC technology, there are more and more challenge for wafer prboe. The ratio of the cost of wafer probe is increased in the total IC manufacutre cost. Hense the business value of wafer probe is becoming important.The familiar abnormal and chanllenge in wafer probe mass production is the accuracy of test result, specifically the overkill issue.The purpose of wafer probe is to identify the good die and bad die in one wafer. It has limit on hardware, software, and test time. All this limit in processs is related to cost. Wafer probe in mass production should guarantee the accuracy base on limited cost. The result of wafer probe is wafer map. If a bad die is identified as a good die, it’s under kill. While if a good die is identified as a bad die, it’s a overkill. The most abnormal case is come from overkill. There are many factor in wafer sort system to induce overkill. It need to identify the factor from mass prodcution, and take the different improvement for various factors. Also need consider the flexibility of implement on mass production situation.This paper collect and study some typical case on overkill issue base on mass prodcution situation. Identify and fix the overkill, fix the abnormal factors to eliminate overkill. Then use PDCA method to perform continuous improement process(CIP) to setup a system to prevent overkill and identify overkill more efficiencily.