Macau University of Science and Technology

Yan Qiao

Mengchu Zhou

Naiqi Wu

Fajun Yang

Qinghua Zhu

Zhiwu Li

Chunrong Pan

A system and method of controlling a cluster tool apparatus, wherein the cluster tool includes one or more processing modules and a robot that is configured to move a semiconductor product to and from the one or more processing modules, the cluster tool configured for processing semiconductor products. The method of controlling the cluster tool apparatus to perform a processing cycle includes receiving a plurality of system parameters from a user interface, wherein the system parameters relate to one or more processing steps of the processing cycle, determining a schedule for performing the processing cycle utilizing the one or more processing modules, wherein the schedule being determined based on a semiconductor product residency parameter.

Cluster tool apparatus and a method of controlling a cluster tool apparatus

A system and method for a cluster tool apparatus for processing a semiconductor product including processing modules located adjacent each other and configured to process a semiconductor module, loadlocks configured to retain and dispense unprocessed semiconductor products and each positioned adjacent one of the processing modules, a robot configured to load, transfer and unload a semiconductor product to and from the processing modules, a hardware controller in communication with the robot and executing a method to close down the cluster tool apparatus to an idle state, the method including determining a status of the processing modules, determining if a close down process is required based on the status or based on a close down signal, and, if required, determining a schedule for a close down process based on a semiconductor product residency parameter, and controlling the operation of the robot based on the schedule to perform the close down process.

A method determines an optimized production schedule of a production line including a hybrid multi-cluster tool formed by a plurality of single-arm tools and dual-arm tools interconnected with each other. The method includes determining time for individual operations of a robotic arm and a processing module in the plurality of single-arm tools and dual-arm tools; determining robot waiting time of the single-arm tools and dual-arm tools based on the time for individual operations and different connection relationships of the plurality of single-arm tools and dual-arm tools; determining whether the optimized production schedule exists using the determined waiting time, wherein the optimized production schedule only exists if the hybrid multi-cluster tool is process-dominant where the robot activity time of the plurality of single-arm tools and dual-arm tools is substantially shorter than processing time at the processing module; and determining the optimized production schedule if the optimized production schedule exists.

System and method for determining an optimized schedule of a production line

Since single and dual-arm tools behave differently, it is difficult to coordinate their activities in a hybrid multi-cluster tool that is composed of both single- and dual-arm tools. Aiming at finding an optimal one-wafer cyclic schedule for a treelike hybrid multi-cluster tool whose bottleneck tool is process-bound, the present work extends a resource-oriented Petri net to model such system. By the developed Petri net model, to find a one-wafer cyclic schedule is to determine robot waiting times. By doing so, it is shown that, for any treelike hybrid multi-cluster tool whose bottleneck tool is process-bound, there is always a one-wafer cyclic schedule. Then, computationally efficient algorithms are developed to obtain the minimal cycle time and the optimal one-wafer cyclic schedule. Examples are given to illustrate the developed method.

Petri net-based optimal one-wafer cyclic scheduling of treelike hybrid multi-cluster tools

The scheduling problem of a multi-cluster tool with a tree topology whose bottleneck tool is process-bound is investigated. A method for scheduling the multi-cluster tool to thereby generate an optimal one-wafer cyclic schedule for this multi-cluster tool is provided. A Petri net (PN) model is developed for the multi-cluster tool by explicitly modeling robot waiting times such that a schedule is determined by setting the robot waiting times. Based on the PN model, sufficient and necessary conditions under which a one-wafer cyclic schedule exists are derived and it is shown that an optimal one-wafer cyclic schedule can be always found. Then, efficient algorithms are given to find the optimal cycle time and its optimal schedule. Examples are used to demonstrate the scheduling method.

Optimal one-wafer scheduling of single-arm multi-cluster tools with tree-like topology

Recent trends of larger wafer and smaller lot sizes bring cluster tools with frequent lot switches. Practitioners must deal with more transient processes during such switches, including start-up and close-down processes. To obtain higher yield, it is necessary to shorten the duration of transient processes. Much prior effort was poured into the modeling and scheduling for the steady state of cluster tools. In the existing literature, no attention has been turned to optimize the close-down process for single-arm cluster tools with wafer residency constraints. This invention intends to do so by 1) developing a Petri net model to analyze their scheduling properties and 2) proposing Petri net-based methods to solve their close-down optimal scheduling problems under different workloads among their process steps. Industrial examples are used to illustrate the effectiveness and application of the proposed methods.

Optimally scheduling of close-down process for single-arm cluster tools with wafer residency time constraints

Due to the trend of using larger wafer diameter and smaller lot size, cluster tools need to switch from processing one lot of wafers to another frequently. It leads to more transient periods in wafer fabrication. Their efficient scheduling and control problems become more and more important. It becomes difficult to solve such problems, especially when wafer residency time constraints must be considered. This work develops a Petri net model to describe the behavior during the start-up transient processes of a single-arm cluster tool. Then, based on the model, for the case that the difference of workloads among the steps is not too large and can be properly balanced, a scheduling algorithm to find an optimal feasible schedule for the start-up process is given. For other cases schedulable at the steady state, a linear programming model is developed to find an optimal feasible schedule for the start-up process.

Scheduling start-up process for time-constrained single-arm cluster tools

A method for scheduling dual-armed cluster tools with wafer revisiting is provided. In order to speed up start-up transient processes, the present invention adopts a program evaluation and review technique for the analysis of start-up transient processes and develops optimization algorithms for their scheduling for dual-arm cluster tools. Then, their complexity is analyzed.

Optimization of start-up transient processes for dual-armed cluster tools with wafer revisiting

In semiconductor manufacturing, there are wafer fabrication processes in cluster tools that need a wafer to visit some processing steps for more than once, leading to a revisiting process. Also, wafers may be subject to wafer residency time constraints. By considering atomic layer deposition (ALD) as a typical wafer revisiting process, this invention studies the challenging scheduling problem of single-arm cluster tools for the ALD process with wafer residency time constraints. By recognizing that the key to this problem is to schedule the robot tasks, the present invention presents different robot task sequencing strategies. With these strategies for different cases, the present invention performs the schedulability analysis and derives the schedulability conditions for such tools for the first time. If schedulable, the present invention proposes scheduling algorithms to obtain an optimal schedule efficiently. Illustrative examples are given to show the application of the proposed concepts and approach.

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Macau, Macao

Yan Qiao