A fault-tolerant algorithm with cycled resetting discount factor in semiconductor manufacturing industry

The threaded-EWMA run-to-run control is an important stable control scheme. However, the process outputs will deviate largely in the first few runs of each cycle if the disturbance follows an IMA(1,1) series with deterministic linear drift/fault and the thread has a long break length. In this paper, we analyzed the output of the threaded-EWMA run-to-run control. Based on the analysis of system performance, cycled resetting (CR) algorithm for discount factor is proposed to reduce the large deviations as well as a step fault to achieve the minimum asymptotic variance control. By analysis the influence of the fault, discount factor resetting and fault tolerant (RFT) approach is presented. Simulation study showed that the proposed approach is effective.