Transient Process Optimization for Dual-Arm Cluster Tools With Wafer Revisiting

Abstract

In wafer fabrication, it is imperative to minimize the transient process of cluster tools for the sake of on-demand and preventive maintenance. Due to the trend of multi-type and small-batch production, transient processes appear more and more frequently. Thus, the optimization problems of transient processes have gained increasing attention from both industry and academia. The requirement for wafer revisiting tend to complicate this problem significantly. However, only a few studies take such a challenge for cluster tools with wafer revisiting. This paper focuses on the schedule optimization of transient processes for dual-arm cluster tools with wafer revisiting. To accelerate transient processes, including both start-up and close-down ones, we adopt a program evaluation and review technique to analyze and harness a cluster tool's state evolution. We then propose computationally efficient algorithms to speed up transient processes. Finally, we provide illustrative examples to show their applications and validate their effectiveness.INDEX TERMS Cluster tool, semiconductor manufacturing, wafer fabrication, scheduling, transient process, wafer revisiting.{0}. PM Process module. SACT Single-arm cluster tool. DACT Dual-arm cluster tool. ALD Atomic layer deposition. WRP Wafer revisiting process. k-WRP k-time Wafer revisiting process. 1-WCS One-wafer cyclic scheduling. 3-WCS Three-wafer cyclic scheduling. VWM Virtual wafer method. SUTP Start-up transient process. CDTP Close-down transient process. PERT Program evaluation and review technique.