Study On Control And Scheduling Of Production In Ic Final Test Production Sysytem Based On Em-plant Softeware

The productive process of IC is very complex,and the cost of the facility for the IC productive line is very high.What's more,the IC production Line has the character of multiple re-entrant,it means the work products need processed in the same process center in different operation stages.So the work products in different process center need compete for the same resource of the same process center.The make the production scheduling much harder.Currently the most research focus on the front end of IC production line,which is more complex and moe expensive,this make the bottleneck of the IC production line transfer from the front end to the back end.And the Final test production line is the important part of IC production line,and also has the character of the multiple re-entrant,unscientific method of scheduling will make the bottleneck more obviously.So the research on the Final test production system is significant to optimize the scheduling of the whole IC production line.This paper will make research on the production scheduling of Final test production system which has two Re-entrant centers,Test center and Oven Center.The work products need to be processed three times in the Test Center and two times in the Oven center,and the sequential scheduling and batch scheduling exist the same time.This paper raise the 4HCS(4 Hierarchy Scheduling Strategy)scheduling strategy based on the DBR and TOC theory.Firstly,confirm the ratio of machines in the key center;Secondly,recognize the bottleneck in the Final Test stage;Thirdly make the batch feeding strategy;Fourthly,make the rule of scheduling in the buffer of the key resource.For the batch feeding strategy,will combine the CONWIP and SA batch feeding strategy,control the open or close the batch feeding based on the WIP status of the buffer of key process,avoiding the starvation of the key process and also avoiding the work product lot start too early with adding the waiting time.For the scheduling rule in the buffer of waiting time.And the simulate the Final test production system with the eM-Plant software,and use the Simtalk language to programme to realize all the function and all the steps in the Final test production system.Finally paper will compare with the usual scheduling strategy based on the index of MinCmax and MinMCT and also balance other,to prove the 4HCS strategy is advantage on the Final Test production system.