As wafer circuit widths shrink down, wafer fabrication processes require stringent quality control. Therefore, fabs recently tend to clean a chamber after processing each wafer, in order to remove chemical residuals within the chamber. Such chamber cleaning, called purge operation, increases scheduling complexity in robotized cluster tools. In this paper, we examine scheduling problems of single-armed cluster tools with purge operations for series-parallel chambers. By extending the wellknown backward sequence, we propose a backward(z) sequence that allows partial loading for parallel chambers, where vector z specifies how many chambers zi of each process step i are kept empty for cleaning. We then propose a way of finding optimal vector z* and identify when backward(z*) achieves the minimum cycle time among all possible sequences. We present experimental results on the accuracy of backward(z*).

中文翻译：

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安排单臂集群工具进行腔室清洁操作


随着晶圆电路宽度缩小，晶圆制造工艺需要严格的质量控制。因此，晶圆厂最近倾向于在处理每个晶圆之后清洁腔室，以去除腔室内的化学残留物。这种室清洁称为净化操作，增加了机器人集群工具中调度的复杂性。在本文中，我们研究了具有串并联室净化操作的单臂集群工具的调度问题。通过扩展众所周知的后向序列，我们提出了后向（z）序列，该序列允许并行腔室的部分加载，其中向量 z 指定每个工艺步骤 i 的多少个腔室 zi 保持空置以进行清洁。然后，我们提出了一种寻找最佳向量 z* 并识别何时 back(z*) 在所有可能序列中实现最小循环时间的方法。我们展示了向后（z*）的准确性的实验结果。