(A) new class of sequences that minimizes work cycle interferences for cluster tools with wafer delay constraints

Abstract

A cluster tool which consists of several single-wafer processing chambers and a wafer-handling robot is widely used in semiconductor manufacturing systems. It is known that the swap and backward sequences are optimal for dual- and single-armed cluster tools, respectively. As wafer fabrication processes become dense and complicated, a cluster tool requires strict wafer delay constraints, and the conventional sequences may not satisfy such time constraints. In the thesis, we suggest a new class of robot task sequences which minimizes work cycle interferences for cluster tools. The suggested sequences are very simple to be performed in practice. Furthermore, we extend the suggested sequences to resolve scheduling issues for chamber cleaning operations. We also suggest the scheduling methods to handle the process time variation in real time. Experimental results show that our suggested robot task sequences have significantly high performance for cluster tools with diverse requirements.