A PRODUCTION PLANNING METHODOLOGY FOR SEMICONDUCTOR MANUFACTURING BASED ON ITERATIVE SIMULATION AND LINEAR-PROGRAMMING CALCULATIONS

We introduce a methodology for automated production planning of semico nductor manufacturing based on iterative linear programming (LP) optim ization and discrete-event simulation calculations, The LP formulation incorporates epoch-dependent parameters for flow times from lot relea se up to each operation on each manufacturing route, LP-derived releas e schedules are used as input to the simulation model, from which stat istics on pow times are collected and used to reformulate the LP model for a revised planning Calculation, Iteration continues until satisfa ctory agreement between simulation and LP models is obtained, We demon strate in experiments on an industry data set that a relatively small number of iterations is required to develop a production plan correctl y characterizing future flow times as a function of factory load and p roduct mix, The methodology makes possible automated production planni ng of semiconductor manufacturing on an engineering work station.