腔室清洗的单臂组合设备初始暂态调度

为了提升腔室洁净度,晶圆厂需对组合设备腔室进行清洗操作,从而提高晶圆的加工质量.考虑腔室清洗时间和晶圆驻留时间的约束条件下,本文研究了单臂组合设备的初始暂态调度问题.首先,提出了机械手的初始暂态活动规则,并对机械手活动序列进行描述,实现了系统的初始暂态可调度性;其次,对机械手在初始暂态和稳态的活动时间进行了建模;然后,根据系统的时间特性,建立了初始暂态调度的线性规划模型;最后,通过实例验证了该方法的有效性.与已有的虚拟晶圆方法相比,该调度方法能有效减少初始暂态的完工时间,提高了组合设备的晶圆生产效率.     

晶圆重入加工的组合设备终止暂态的调度与分析

晶圆重入是半导体组合设备加工中典型的复杂加工工艺,分析和优化暂态加工过程对于晶圆重入加工具有重要意义.为了满足加工需求和提高组合设备的加工性能,基于稳态重入加工的双臂组合设备Petri网模型和1-晶圆周期调度策略,采用虚拟晶圆的加工模式分析了系统的终止暂态过程,讨论了系统终止暂态的加工时间分布,并给出相应的解析式进行描述.利用eM-Plant仿真平台建立了重入加工的双臂组合设备终止暂态的仿真模型,并用例子验证了1-晶圆周期调度的可行性及解析式的有效性,为研究晶圆重入加工过程的优化提供了有效方法和手段.     

稳态调度下单臂组合设备时间延迟分析与优化

在半导体晶圆制造过程中,驻留时间延迟过长对晶圆质量具有消极影响.本文研究单臂组合设备稳态调度中如何合理地分配机械手等待时间,抵消驻留时间延迟的问题.首先,采用Petri网模型描述晶圆制造过程,分析了单臂组合设备稳态调度的时间特性,获得了稳态下工序驻留时间延迟计算表达式.其次,通过解构机械手等待时间对驻留时间延迟的影响机理,提出了一种机械手等待时间分配优先级规则.进一步,将虚拟瓶颈工序用于辅助分配机械手等待时间,结合优先级规则,提出了一种单臂组合设备稳态调度启发式算法.最后,通过例子验证了算法的可行性与有效性.与传统拉式策略和尽早加工策略对比,该算法能有效地减少单臂组合设备稳态调度下的驻留时间延迟并能满足晶圆制造的严格要求.     

面向单臂组合设备中紧急订单的调度

随着晶圆制造模式向多品种、小批量的转变，在实际生产过程中频繁出现紧急订单插入的情况，不合理的调度策略将降低组合设备生产效率。为了提高组合设备的生产柔性，研究了在考虑晶圆逗留时间约束条件下，单臂组合设备面对紧急插单时的调度问题。首先，对紧急插单的加工过程进行分析，提出针对单臂组合设备的机械手调度规则，实现了加工过程的可调度性。其次，对于因加工参数不同产生的两种加工状态，分别推导出可调度性判断条件，然后给出用于求解机械手等待时间的数学解析式。最后，提出组合设备面对紧急插单时的最优调度算法，并通过实例验证和对比分析的方法验证了该调度方法的有效性。     

具有多品种晶圆混合加工的单臂组合设备调度

为了提高晶圆制造中组合设备的生产效率,在考虑晶圆驻留时间约束条件下,研究没有共享加工模块的多品种晶圆混合加工的单臂组合设备调度问题.首先,采用面向资源的Petri网模型描述多种晶圆产品的混合加工过程,引入控制变迁避免模型的死锁,采用赋时库所和赋时变迁模拟系统资源的活动时间.其次,通过虚拟加工的方法平衡工序的负载,基于系统Petri网模型和拉式调度策略,推导出单臂组合设备在多品种晶圆混合加工情形下的可调度性判定条件,并以解析形式描述.最后,提出了系统稳态调度求解算法并以实例验证了算法的有效性和可行性.     

基于Petri网的组合设备建模与调度综述

组合设备是半导体晶圆制造的核心装备,其调度与控制优化是半导体制造领域极具挑战性的课题. Petri网因其强大的建模能力和简约的图形化表达优势,被广泛地应用于组合设备的建模与调度.对基于Petri网的组合设备建模与调度方法进行综述,归纳总结了组合设备的结构类型、晶圆流模式、调度策略及Petri网建模方法,并系统阐述组合设备的7类典型调度问题,包括驻留时间约束、作业时间波动、晶圆重入加工、多品种晶圆加工、加工模块(Process module, PM)故障、PM清洗和组合设备群.最后,讨论了当前组合设备调度存在的挑战及后续可能的研究方向.     

基于eM-Plant的虚拟晶圆制造自动组合装置

针对难以用解析法验证半导体加工装置的调度可行性问题,提出仿真建模研究的新方法。利用仿真软件eM-Plant建立晶圆制造中单臂自动组合装置的参数化仿真模型,构建一个虚拟的晶圆制造系统。该系统为研究自动组合装置控制问题提供有效手段,是验证半导体制造生产调度可行性的仿真平台。     

基于时间约束集的集束型设备群调度方法

随着300mm晶圆的加工技术问世,工业界开始采用一种全新的晶圆制造设备——集束型设备群(Multi-cluster tools).对于单个集束型设备(Single-cluster tools)调度研究已比较成熟,并提出了多种调度方法,然而对于集束型设备群调度研究尚处在一个起步阶段. 本文对带有驻留约束且具有多种晶圆类型的集束型设备群的调度问题进行了研究,在引入时间约束集概念的基础上建立了调度模型, 同时,提出了一种逐级回溯的调度方法,并对调度算法进行了仿真实验分析. 仿真结果表明本文提出的算法是有效且可行的.     

多目标环境下的生产资源平衡和优化调度研究

基于调度周期订单所映射的工件集合,讨论了以生产资源和工艺方案为约束的多工艺方案推荐方法,有目的地为生产调度进行工艺选择,提高生产调度的运行效率.基于遗传算法,考虑设备负荷均衡、关键设备利用率、所有设备利用率等多目标,进行了基于可用资源的生产调度基础数据优化处理.结合实例,根据不同的目标得到了有效的可选工艺方案,仿真结果表明,经过生产资源平衡后,较易得到满意的调度方案.     

单阶段多产品批处理过程的短期调度1. 基本模型的建立

具有并行设备的多产品单阶段批处理过程短期 调度问题需考虑订单发布时间、交货期，订单生产的顺序相关建立时间、禁止生产子序列， 及设备的准备时间等生产约束．本文在考虑上述约束的基础的上，利用时间间隙的概念和连 续时间表达，将设备、订单分配给时间间隙分别表达为两类0-1变量，建立了具有并行生产 线的多产品单阶段批处理过程的短期调度数学模型．模型表达为一个混合整数规划（MILP） 问题．该模型不但比已有的基于时间间隙描述的调度模型0-1变量少，而且能优 化多种目标函数．本文的第二部分将引入一些适当的启发性规则，减小了模型的规模，并应 用大量的计算实例说明该模型的有效性和适用性．     

Optimal Integrated Schedule of Entire Process of Dual-blade Multi-cluster Tools From Start-up to Close-down

Multi-cluster tools are widely used in majority of wafer fabrication processes in semiconductor industry. Smaller lot production, thinner circuit width in wafers, larger wafer size, and maintenance have resulted in a large quantity of their start-up and close-down transient periods. Yet, most of existing efforts have been concentrated on scheduling their steady states. Different from such efforts, this work schedules their transient and steady-state periods subject to wafer residency constraints. It gives the schedulability conditions for the steady-state scheduling of dual-blade robotic multi-cluster tools and a corresponding algorithm for finding an optimal schedule. Based on the robot synchronization conditions, a linear program is proposed to figure out an optimal schedule for a start-up period, which ensures a tool to enter the desired optimal steady state. Another linear program is proposed to find an optimal schedule for a close-down period that evolves from the steady state period. Finally, industrial cases are presented to illustrate how the provided method outperforms the existing approach in terms of system throughput improvement.      

Cycle time analysis for wafer revisiting process in scheduling of single-arm cluster tools

Some wafer fabrication processes performed by cluster tools require revisiting. With wafer revisiting, a cluster tool is very difficult to be scheduled due to a large number of possible schedules for the revisiting process. Atomic layer deposition (ALD) is a typical process with wafer revisiting that should be performed by cluster tools. This paper discusses the scheduling problem of single-arm cluster tools for the ALD process. In scheduling such a system, the most difficult part is to schedule the revisit...     

Post-Processing Time-Aware Optimal Scheduling of Single Robotic Cluster Tools

Integrated circuit chips are produced on silicon wafers. Robotic cluster tools are widely used since they provide a reconfigurable and efficient environment for most wafer fabrication processes. Recent advances in new semiconductor materials bring about new functionality for integrated circuits. After a wafer is processed in a processing chamber, the wafer should be removed from there as fast as possible to guarantee its high-quality integrated circuits. Meanwhile, maximization of the throughput of robotic cluster tools is desired. This work aims to perform post-processing time-aware scheduling for such tools subject to wafer residency time constraints. To do so, closed-form expression algorithms are derived to compute robot waiting time accurately upon the analysis of particular events of robot waiting for single-arm cluster tools. Examples are given to show the application and effectiveness of the proposed algorithms.      

Scheduling Dual-Arm Cluster Tools With Multiple Wafer Types and Residency Time Constraints

Accompanying the unceasing progress of integrated circuit manufacturing technology, the mainstream production mode of current semiconductor wafer fabrication is featured with multi-variety, small batch, and individual customization, which poses a huge challenge to the scheduling of cluster tools with single-wafer-type fabrication. Concurrent processing multiple wafer types in cluster tools, as a novel production pattern, has drawn increasing attention from industry to academia, whereas the corresponding research remains insufficient. This paper investigates the scheduling problems of dual-arm cluster tools with multiple wafer types and residency time constraints. To pursue an easy-to-implement cyclic operation under diverse flow patterns,we develop a novel robot activity strategy called multiplex swap sequence. In the light of the virtual module technology, the workloads that stem from bottleneck process steps and asymmetrical process configuration are balanced satisfactorily. Moreover, several sufficient and necessary conditions with closed-form expressions are obtained for checking the system's schedulability. Finally, efficient algorithms with polynomial complexity are developed to find the periodic scheduling, and its practicability and availability are demonstrated by the offered illustrative examples.     

有滞留时间约束的集束型装备在线调度问题研究

针对半导体制造中有滞留时间约束的集束型装备,研究了临时晶网到达时的在线调度问题,描述了调度问题域.建立了问题的数学模型,并根据模型提出了两层调度方法.外层算法通过粒子群优化过程求解临时晶网的加工顺序;内层算法在给定加工顺序的基础上,采用前向和后向递推方法获得口,行解窄问,并从可行解窄问获得最优完工时间.从理论上证明了算...