Search query: Production control in semiconductor manufacturing with time constraints

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abstract: In this paper, production of lots under time constraints in a semiconductor wafer fabrication is investigated. A time constraint covers a sequence of process steps and has a maximum time that lots must spend in these steps. Lots which violate a recommended time constraint have to be scrapped or reprocessed. Accordingly, controlling the entrance of lots in a time constraint is critical in semiconductor fabrication. An approach is developed to estimate whether a given lot may satisfy time constraints or not. Some numerical experiments are presented with industrial data.
author_names: Rezvan Sadeghi

Stephane Dauzere-Peres

Claude Yugma

Guillaume Lepelletier
title: Production control in semiconductor manufacturing with time constraints
venue: 2015 26th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)
year: 2015

abstract: This paper investigates and compares different control mechanisms for timelink areas in a semiconductor manufacturing line with tool downs. Timelinks are time constraints between consecutive process steps. The goal of this paper is to search for good and practicable control mechanisms, that determine optimal release dates for lots in front of a timelink area with a minimum of time constraint violations. To evaluate good control mechanisms, this paper will investigate risk factors which are based especially on failure probability of tools, with the aid of survival analysis, at the end of a timelink area. These risk factors will be included in a mixed integer program (MIP) together with the time constraints. To test the developed scheduling method the MIP will be simulated in a hybrid model (symbioses of simulation and a mathematical solver) under the aspect of rolling horizon planning with a simulation of unscheduled tool downs. On the basis of the failure probability there will be also different capacity calculations to derive and compare dispatching rules. The dispatching rules are tested by a discrete simulation model that considers also unscheduled tool downs. At last the results of the MIP are compared with the prepared dispatching rules.
author_names: Christian Maleck

Tobias Eckert
title: A comparison of control methods for production areas with time constraints and tool interruptions in semiconductor manufacturing
venue: 2017 40th International Spring Seminar on Electronics Technology (ISSE)
year: 2017

abstract: In this paper we will present a multi stage scheduling approach to generate robust schedules for a challenging aspect of semiconductor manufacturing called time link areas. A time link is a technologically induced time constraint between one or more consecutive process steps requiring the process steps to be executed within a predefined time window. Time links are often introduced to control contamination or unwanted oxidation. Violating time link constraints may lead to extra effort due to additional rework steps and may have negative yield impact or may even, result in scrap.
author_names: Christian Maleck

Gottfried Nieke

Karlheinz Bock

Detlef Pabst

Meinhard Schulze

Marcel Stehli
title: A Robust Multi Stage Scheduling Approach for Semiconductor Manufacturing Production Areas with Time Contraints
venue: 2019 30th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)
year: 2019

abstract: This research develops production control methods for multi product systems under process queue time (PQT) constraints.A single flexible upstream workstation and multiple dedicated downstream workstations are considered.Under the PQT constraint, jobs are scrapped if the waiting time before a queue is longer than a pre defined upper limit.An innovative multiple product admission control heuristic is developed using Markov decision processes.The proposed MPAC method reduces production costs and scrap counts by 33.8% and 59.5% in our numerical study. In a multi product manufacture system, the complexity of production control increases. Because multiple products are competing for limited resource, managers need to dynamically adjust production priority based on customer demand and distribution of work in processes (WIP) The production control in multi product system becomes even more complicated when process queue time (PQT) constraints exist. Under PQT constraints, administrators setup upper limits for the waiting time between specific manufacturing steps to ensure quality of products. This upper limit of waiting time makes dynamic production control very challenging.The objective of this paper is to develop production control methods for multi product systems subject to PQT constraints. However, it is computationally infeasible to solve multiple product problems in a single dynamic optimization model, and we therefore first formulate a single product admission control problems using Markov decision processes (MDP) Based on observations from the single product MDP model, an innovative multiple product admission control (MPAC) heuristic is developed. In simulation study, we compare the performance of MPAC with other popular dispatching methods in literature. Compare to other control methods in literature, the proposed (MPAC) method can reduce production costs by at least 33.8% and reduce scrap count by at least 59.5% in average.
author_names: Cheng-Hung Wu

Wen-Chi Chien

Ya-Tang Chuang

Yu-Ching Cheng
title: Multiple product admission control in semiconductor manufacturing systems with process queue time (PQT) constraints
venue: Comput. Ind. Eng.
year: 2016

abstract: Reinforcement learning (RL) offers promising opportunities to handle the ever increasing complexity in managing modern production systems. We apply a Q learning algorithm in combination with a process based discrete event simulation in order to train a self learning, intelligent, and autonomous agent for the decision problem of order dispatching in a complex job shop with strict time constraints. For the first time, we combine RL in production control with strict time constraints. The simulation represents the characteristics of complex job shops typically found in semiconductor manufacturing. A real world use case from a wafer fab is addressed with a developed and implemented framework. The performance of an RL approach and benchmark heuristics are compared. It is shown that RL can be successfully applied to manage order dispatching in a complex environment including time constraints. An RL agent with a gain function rewarding the selection of the least critical order with respect to time constraints beats heuristic rules strictly by picking the most critical lot first. Hence, this work demonstrates that a self learning agent can successfully manage time constraints with the agent performing better than the traditional benchmark, a time constraint heuristic combining due date deviations and a classical first in first out approach.
author_names: Thomas Altenmuller

Tillmann Stuker

Bernd Waschneck

Andreas Kuhnle

Gisela Lanza
title: Reinforcement learning for an intelligent and autonomous production control of complex job shops under time constraints
year: 2020

abstract: Abstract Waiting time constraints between two processes are one of common scheduling requirements in many production systems, such as semiconductor, automotive, food, and battery manufacturing. When the time constraints are introduced, quality inspection should be carried out on parts that have exceeded a given time limit and such parts are subject to be re processed or scrapped, which incurs additional expenses and efforts. Therefore, the foremost goal is to maximize yield, which is defined by the production rate of parts that do not violate the time constraints. In this paper, we present a mathematical model of Bernoulli production lines to evaluate yield and examine its properties with respect to time constraints, buffer capacity, and machine reliability. System properties such as monotonicity and asymptotic characteristics are analyzed. With the analysis results, an efficient algorithm to design an optimal buffer capacity is developed. It is shown that, in contrast to traditional production lines, there is no monotonicity of yield on the reliability of an upstream machine; that is, an upstream machine becoming more reliable does not always contribute to increasing yield. Therefore, optimal control policies are presented to control the upstream machine for maximal yield. Finally, a case study is introduced to illustrate the applicability of the method.
author_names: Jun-Ho Lee

Cong Zhao

Jingshan Li

C T Papadopoulos
title: Analysis, design, and control of Bernoulli production lines with waiting time constraints
year: 2018

abstract: Semiconductor manufacturing processes often come with stringent requirements for product quality. In order to satisfy these requirements, time window constraints have been imposed. Typically, violation of the time windows can result in a lot being either reworked or scrapped. The presence of overlapped time window constraints renders the control of production lines very challenging as it involves managing the production process of many lots across multiple workstations. We study the performance of a production line with deterministic service times and predetermined, overlapped time windows. We solve the {P|r_{j}|C_{\max problem to estimate the queue time at each workstation, and develop an algorithm to decide whether a new lot can be released for processing at its first workstation so as to meet all time window constraints.
author_names: MengChang Wang

Sandeep Srivathsan

Edward Huang

Kan Wu
title: Job Dispatch Control for Production Lines With Overlapped Time Window Constraints
venue: IEEE Transactions on Semiconductor Manufacturing
year: 2018

abstract: Scheduling optimization in semiconductor manufacturing is always a crucial task in production performance indicators such as machine utilization, cycle time and delivery times. With the increasing complexity of fabrication techniques and scales, scheduling and control activities are inevitably confronted with each other and shall be integrated correspondingly. In particular scheduling and control are mutually dependent as control requires decisions from schedules, and scheduling should take control information into account. Based on a literature survey, we propose a general review and an outlook of the expected improvements related to binding scheduling decisions and information/constraints coming from Advanced Process Control systems in semiconductor manufacturing. Potential issues and tasks concerning this integration are addressed in this paper in order to stimulate more work in research and industrial practices.
author_names: Claude Yugma

Jakey Blue

Stephane Dauzere-Peres

Philippe Vialletelle
title: Integration of scheduling and advanced process control in semiconductor manufacturing: review and outlook
venue: CASE
year: 2014

abstract: Abstract It is commonly observed in the food industry, battery production, automotive paint shop, and semiconductor manufacturing that an intermediate product's residence time in the buffer within a production line is controlled by a time window to guarantee product quality. There is typically a minimum time limit reflected by a part's travel time or process requirement. Meanwhile, these intermediate parts are prevented from staying in the buffer for too long by an upper time limit, exceeding which a part will be scrapped or need additional treatment. To increase production throughput and reduce scrap, one needs to control machines' working mode according to real time system information in the stochastic production environment, which is a difficult problem to solve, due to the system's complexity. In this article, we propose a novel decomposition based control approach by decomposing a production system into small scale subsystems based on domain knowledge and their structural relationship. An iterative aggregation procedure is then used to generate a production control policy with convergence guarantee. Numerical studies suggest that the decomposition based control approach outperforms general purpose reinforcement learning method by delivering significant system performance improvement and substantial reduction on computation overhead.
author_names: Feifan Wang

Feng Ju
title: Decomposition based real time control of multi stage transfer lines with residence time constraints
venue: IISE Trans.
year: 2021

abstract: This paper presented solutions respond to three issues of scheduling of semiconductor manufacturing. As the First, we introduced how to apply SCKB REFS rule, which is the optimal re entrant flow dispatching for maximizing throughput of quality product in Q time constraints processes, to the case of more than two different re entrant flows. The performance of SCKB REFS rule is evaluated by comparing with typical rules, FCFS CT and LPFS CT, in case that three different flows (i.e. specifications) share the same production tools. SCKB REFS rule achieved the best performance in terms of mean cycle time and the throughput ratio in every traffic intensity as the result.
author_names: Akihiro Kobayashi

Takahiro Kuno

Sumika Arima
title: Re entrant flow control in Q time constraints processes for actual applications
venue: 2013 e Manufacturing Design Collaboration Symposium (eMDC)
year: 2013