A study of a method to improve the productivity of mixed semiconductor manufacturing

我从以下两个角度来进行这个项目；对调度算法进行了研究，并对制造模拟器的开发进行了研究。提出了一种用于在制品动态分配的新调度算法——伪周期优先级调度算法。研究了应用P3D时的性能参数、调整速率、吞吐量、响应时间和延迟性，并通过泊松到达的模拟与FCFS和SPT的结果进行了比较。调整速率最小为P3D。P3D在瓶颈建模的加工步骤和非瓶颈建模的加工步骤中都是有效的。特别是在瓶颈建模的处理步骤中，虽然SPT的平均响应时间最小，但P3D的平均响应时间约为FCFS的65%，P3D的延迟时间约为SPT的28%。然后对P3D进行确认，实现了公平调度。最后得出结论：P3D是一种适用于大产品组合的有效调度算法。基于彩色Petri网理论开发了制造模拟器。半导体制造系统可以用一个环型网络来描述，尽管该系统有300多个加工步骤。然而，描述半导体制造系统需要新的机制。应定义与处理步骤相对应的令牌的新属性，并通过参考大规模集成电路制造的序列表来定义转换的属性。此外，我还提出了一些新的Petri网组件，以方便地描述系统。在实际半导体设备中的评估将是本研究的未来主题。

I performed this project from fo11owing two view points; a research on a dispatching algorithm, and a research on a development of a manufacturing simulator.A new dispatching algorithm for dynamic allocation of Work-In-Process (WIP) named Pseudo Periodical Priority Dispatching (P3D) is proposed. Performance parameters, adjustment rate, throughput, response time and tardiness, when applying P3D are studied and compared with the results of FCFS and SPT by simulations assuming a Poisson arrival. The adjustment rate is the minimum is P3D. P3D is effective both in the bottleneck modeled processing step and in the non-bottleneck modeled processing step. Especially in the bottleneck modeled processing step, although the average response time of SPT is minimum, that for P3D is about 65% of that for FCFS and the tardiness for P3D is about 28% of that for SPT. Then P3D is confirmed that the fair dispatching is achieved. Finally the author concluded that P3D is an effective dispatching algorithm in the case of the broad product-mix.The manufacturing simulator is developed based on a color Petri Net theory. The semiconductor manufacturing system can be described by a loop-type net, although the system has more than 300 processing steps. However, new mechanisms are required for describing the semiconductor manufacturing system. A new attributes shall be defined for the tokens corresponding to the processing step, and attribute for the transition shall be defined by referring the sequence table for the LSI fabrication. Also I have proposed some new component for the Petri Net to describe the system easily.The evaluation in the actual semiconductor facilities will be the future subject of this research.