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

本课题从调度算法研究和制造仿真系统开发两个方面展开，提出了一种新的在制品动态分配调度算法--伪周期优先调度算法（P3 D）。性能参数，调整率，吞吐量，响应时间和拖期，当应用P3 D的FCFS和SPT的结果进行了研究和比较，通过模拟假设泊松到达。调整率最小为P3 D。P3 D在瓶颈建模加工步骤和非瓶颈建模加工步骤中均有效。特别是在瓶颈模型的处理步骤中，虽然SPT的平均响应时间最小，但P3 D的平均响应时间约为FCFS的65%，P3 D的拖期约为SPT的28%。然后，P3 D被确认为实现了公平调度。最后，作者得出结论，P3 D是一种有效的调度算法的情况下，广泛的产品组合。半导体制造系统可以用一个环型网来描述，尽管该系统有300多个处理步骤。然而，需要新的机制来描述半导体制造系统。应针对与处理步骤相对应的标记定义新属性，并且应通过参考LSI制造的序列表来定义转换的属性。此外，我也提出了一些新的Petri网组件，以便于描述系统。在实际的半导体设备的评估将是未来的研究课题。

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.