Study On Capacity Improvement Of TiW Etching Equipment Based On Witness Simulation Technology

As we know,in the semiconductor fab for packaging and testing, cost controlling in production is a key index both for management efficiency and overall competitiveness. As the competition in the semiconductor industry is more and more fierce, the leaders must find a better solution to control the production cost and reduce it after all. More and more company realize that it is feasible to reduce the equipment investment by increasing the on-hand equipment capacity through varies methods.With the complex manufacturing system in semiconductor industry, traditional methods contribute little in capacity analysis and have difficulty in searching for potential room of capacity increasing.In this paper, we mainly focus on the TiW etching stage in the gold bump process. We will use working hour analysis, model simulation and sensitivity analysis to find a way for capacity improvement.First, this paper analyzes the working flow of TiW etching; Second, set up a model by Witness to simulate the whole working flow, including wafer storage, transmission, etching(2 steps), washing and packaging; Third, study the capacity by adjusting single parameter, such as processing time, equipment setting time, parameter setting time and so on; Forth,study the capacity through multi parameters adjustment under practical engineering constraints. Simulation results show that TiW etching tank one processing time reduced by 6%, setting time reduced by 630 seconds and the parameter setting time reduced by 8 seconds can make the productivity capacity increase 10%.With the help of sensitivity analysis, this paper finds a solution and applies it in the production. Finally, the equipment capacity is increased by 10% without any cost. Daily capacity has increased from 1564pcs to 1743pcs. No significant effect on product quality before and after improvement. Undercut and TiW residue ppm, two quality indexes, are both in the normal level.This study results in good economic benefits. Different from the traditional way of capacity study, this paper simulate the whole process flow by setting up the TiW etching stage in Witness. Furthermore, the results are based on operation research and sensitivity analysis,it has universal reference value to similar etching process or semiconductor manufacturing process.