具有清洗工艺的单臂组合设备终止暂态调度

随着多品种小批量生产模式的普及,导致了组合设备频繁的暂态加工过程.为了提高组合设备的生产柔性,同时考虑晶圆驻留时间约束和腔室清洗时间约束,研究了单臂组合设备的终止暂态调度问题.首先,提出了 1-周期清洗工艺的暂态调度规则,并采用了面向资源的Petri网对单臂组合设备的终止暂态过程进行建模,引入避免死锁的变迁触发规则;其次,根据系统的终止暂态时间特性并考虑不同的调度情形,建立了终止暂态调度的线性规划模型;最后,通过实例验证了该方法的可行性.实验结果表明,与运用改进拉式策略的虚拟晶圆方案相比,该调度方案可有效地减少组合设备终止暂态的完工时间,并满足晶圆制造的工艺要求.

Scheduling of close-down process for single-arm cluster tools with chamber cleaning operations

With the model of multi-variety and small-batch production applied widely, it led to frequent transient process of cluster tools. In order to improve the production flexibility of single-arm cluster tools, the scheduling of close-down process problem is addressed considering the time constraints of wafer residency and chamber cleaning. Firstly, a transient scheduling rule with 1-period of cleaning operations is proposed. Resource-oriented Petri net is used to model the closedown process of single-arm cluster tools and a rule of transition firing is introduced to avoid deadlock. Secondly, according to the close-down process time characteristics of the system and different scheduling situations, a corresponding linear programming model is established to achieve close-down process optimal scheduling. Finally, examples are given to verify the feasibility of the proposed approach. The experimental results show that the scheduling scheme can effectively reduce close-down process makespan of single-arm cluster tools and meet wafer fabrication process requirements, compared with the virtual wafer method based on extended backward strategy.