具有晶圆重入加工的双臂组合设备终止暂态研究

发布时间：2018-10-26 19:57

【摘要】：晶圆制造是半导体制造过程的核心环节,随着晶圆的直径逐渐增大,加工工序日趋复杂,大直径的晶圆广泛采用组合设备(Cluster tools)加工。由于组合设备密闭空间的限制,内部除了机械手没有其他缓冲区,造成组合设备的运行控制异常困难。某些晶圆的加工常常出现重入加工,如原子层沉积(atomic layer deposition,ALD)通过多次重入加工达到离子层的厚度要求,这使组合设备出现死锁(deadlock)的可能性增大,其调度与控制也更复杂。对于具有重入加工的组合设备建模与调度,现有的研究都侧重于稳态条件下。然而,晶圆加工过程须经历初始暂态、稳态、终止暂态三个阶段,终止暂态加工过程的分析和优化对提高系统加工效率及多品种、少批量的加工趋势具有重要的实践意义。由于组合设备中资源的限制,采用有限资源的赋时Petri网(Timed Petri net,TPN)模拟系统能准确地描述晶圆加工的并行且异步事件,以及各资源之间的逻辑关系。因此,本文基于双臂组合设备稳态的Petri网模型和1-晶圆周期调度策略,采用虚拟晶圆的加工方式描述和分析了双臂组合设备晶圆重入加工的终止暂态过程,讨论了一般条件下系统终止暂态的加工时间分布,并采用解析式进行描述。基于1-晶圆周期调度的终止暂态过程的分析,以减少终止暂态的加工时间为目标,对终止暂态的加工过程调度进行优化,构建了双臂组合设备终止暂态改进的Petri网模型,并提出1-晶圆优化调度策略,使系统能快速切换至另一批晶圆产品的加工。同时,讨论了终止暂态加工时间分布,并通过解析式有效地表达出来。以Plant Simulation软件为仿真平台,分别建立了基于1-晶圆周期调度和1-晶圆优化调度的双臂组合设备的仿真模型,实现了不同调度策略的终止暂态仿真,并通过一些例子获得了两组终止暂态的加工时间。对比同等加工条件下的终止暂态加工时间可知,1-晶圆优化调度能明显改善终止暂态的加工过程并提高晶圆的加工效率,由此验证了优化调度的可行性和解析式的有效性。最后,对全文进行回顾,分析了内容中有待改进之处,指出了进一步的研究方向。
[Abstract]:Wafer manufacturing is the core of semiconductor manufacturing process. With the increasing of wafer diameter, the processing process is becoming more and more complex. The large diameter wafer is widely used in (Cluster tools) processing. Due to the limitation of the closed space of the combined equipment, there are no other buffers in the inner part except the manipulator, which makes the operation and control of the combined equipment extremely difficult. Some wafer processing often occurs reentry processing, such as atomic layer deposition (atomic layer deposition,ALD) through multiple reentry processing to meet the ion layer thickness requirements, which makes the combination equipment deadlock (deadlock) is more likely, Its scheduling and control are more complex. For the modeling and scheduling of combined equipment with reentry machining, the existing research focuses on steady state conditions. However, the analysis and optimization of the process of wafer processing must go through three stages: initial transient, steady state and termination transient. The analysis and optimization of the termination transient processing process have important practical significance for improving the system processing efficiency and variety, and less batch processing trend. Due to the limitation of resources in combinatorial devices, the time-timed Petri net (Timed Petri net,TPN) simulation system with finite resources can accurately describe the parallel and asynchronous events of wafer processing and the logical relationship between each resource. Therefore, based on the steady-state Petri net model and 1-wafer periodic scheduling strategy of dual-arm combinatorial equipment, this paper describes and analyzes the termination transient process of wafer reentry of dual-arm combiner by using virtual wafer machining method. The processing time distribution of system termination transient under general conditions is discussed and described by analytic formula. Based on the analysis of the termination transient process of 1- wafer periodic dispatching, with the goal of reducing the processing time of the termination transient, the process scheduling of the termination transient is optimized, and the improved Petri net model for the termination transient of the dual-arm combinational equipment is constructed. A 1-wafer optimal scheduling strategy is proposed to enable the system to quickly switch to another batch of wafer products. At the same time, the distribution of termination transient processing time is discussed and expressed effectively by analytic formula. Using Plant Simulation software as the simulation platform, the simulation models of dual-arm combinational equipment based on 1-wafer periodic scheduling and 1-wafer optimal scheduling are established, and the termination transient simulation of different scheduling strategies is realized. The processing time of two groups of termination transient is obtained by some examples. Compared with the processing time of termination transient under the same processing conditions, 1- wafer optimal scheduling can obviously improve the processing process of termination transient and improve the processing efficiency of wafer, which verifies the feasibility of optimal scheduling and the validity of analytical formula. Finally, the paper reviews the whole paper, analyzes the content of the need for improvement, and points out the direction of further research.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN405

【参考文献】