Yield integrated scheduling using machine condition parameter

Currently machines in a parallel work center in semiconductor manufactory are assumed uniform in terms of impact on yield for most logic to dispatch schedule this machine set. But in reality machines are different even though they are allowed for the same products. In some layer forming areas machines can get a so called health parameter which describes the current condition of the machine. A high health value means, that defects produced with a machine are less probable. Also the products, which are processed at this work center, differ in their complexity and wafer area used for one chip. The goal is to schedule products with a high complexity and a larger chip size to those machines with the best health value. Doing so will minimize defect wafer area. For this, different dispatching rules and a mixed integer programming approach are compared within a simulation model for practical test data.