Product-mix decision in a mixed-yield wafer fabrication scenario

Abstract

The product mix decision problem for semiconductor manufacturing has been extensively studied in literature. However, most of them are based on a high-yield scenario. Yet, in a low-yield manufacturing environment, some research claims that scrap low-yield lots in an early stage may produce more profit. Considering the early scrapping characteristics, this paper aims to solve the product mix decision problem for a mixed-yield scenario, which involves the simultaneous production of high-yield and low-yield products. A nonlinear mathematical program is developed to model the decision problem. Two methods for solving the nonlinear program are proposed. Method 1 converts the nonlinear program into a linear program by setting some variables as parameters. The method provides an optimal solution by exhaustively searching these parameterized variables and solving the LP models iteratively. Method 2 aims to reduce the computation complexity while providing a near optimal solution. Experiment results show that method 2 is better than method 1, when aggregately considering solution quality and computation efforts.