Cycle Time Analysis For Photolithography Tools In Semiconductor Manufacturing Industry With Simulation Model : A Case Study [TR940. S618 2008 f rb].

Perkembangan industri semikonduktor dalam bidang fabrikasi biasanya melibatkan kos pelaburan yang tinggi terutamanya dalam alatan photolithography. The industry of semiconductor wafer fabrication (“fab”) has invested a huge amount of capital on the manufacturing equipments particular in photolithograph

Entwicklung und Einführung von Produktionssteuerungsverbesserungen für die kundenorientierte Halbleiterfertigung

Production control in a semiconductor production facility is a very complex and timeconsuming task. Different demands regarding facility performance parameters are defined by customer and facility management. These requirements are usually opponents, and an efficient strategy is not simple to define. In semiconductor manufacturing, the available production control systems often use priorities to define the importance of each production lot. The production lots are ranked according to the defined priorities. This process is called dispatching. The priority allocation is carried out by special algorithms. In literature, a huge variety of different strategies and rules is available. For the semiconductor foundry business, there is a need for a very flexible and adaptable policy taking the facility state and the defined requirements into account. At our case the production processes are characterized by a low-volume high-mix product portfolio. This portfolio causes additional stability problems and performance lags. The unstable characteristic increases the influence of reasonable production control logic. This thesis offers a very flexible and adaptable production control policy. This policy is based on a detailed facility model with real-life production data. The data is extracted from a real high-mix low-volume semiconductor facility. The dispatching strategy combines several dispatching rules. Different requirements like line balance, throughput optimization and on-time delivery targets can be taken into account. An automated detailed facility model calculates a semi-optimal combination of the different dispatching rules under a defined objective function. The objective function includes different demands from the management and the customer. The optimization is realized by a genetic heuristic for a fast and efficient finding of a close-to-optimal solution. The strategy is evaluated with real-life production data. The analysis with the detailed facility model of this fab shows an average improvement of 5% to 8% for several facility performance parameters like cycle time per mask layer. Finally the approach is realized and applied at a typical high-mix low-volume semiconductor facility. The system realization bases on a JAVA implementation. This implementation includes common state-of-the-art technologies such as web services. The system replaces the older production control solution. Besides the dispatching algorithm, the production policy includes the possibility to skip several metrology operations under defined boundary conditions. In a real-life production process, not all metrology operations are necessary for each lot. The thesis evaluates the influence of the sampling mechanism to the production process. The solution is included into the system implementation as a framework to assign different sampling rules to different metrology operations. Evaluations show greater improvements at bottleneck situations. After the productive introduction and usage of both systems, the practical results are evaluated. The staff survey offers good acceptance and response to the system. Furthermore positive effects on the performance measures are visible. The implemented system became part of the daily tools of a real semiconductor facility.Produktionssteuerung im Bereich der kundenorientierten Halbleiterfertigung ist heutzutage eine sehr komplexe und zeitintensive Aufgabe. Verschiedene Anforderungen bezüglich der Fabrikperformance werden seitens der Kunden als auch des Fabrikmanagements definiert. Diese Anforderungen stehen oftmals in Konkurrenz. Dadurch ist eine effiziente Strategie zur Kompromissfindung nicht einfach zu definieren. Heutige Halbleiterfabriken mit ihren verfügbaren Produktionssteuerungssystemen nutzen oft prioritätsbasierte Lösungen zur Definition der Wichtigkeit eines jeden Produktionsloses. Anhand dieser Prioritäten werden die Produktionslose sortiert und bearbeitet. In der Literatur existiert eine große Bandbreite verschiedener Algorithmen. Im Bereich der kundenorientierten Halbleiterfertigung wird eine sehr flexible und anpassbare Strategie benötigt, die auch den aktuellen Fabrikzustand als auch die wechselnden Kundenanforderungen berücksichtigt. Dies gilt insbesondere für den hochvariablen geringvolumigen Produktionsfall. Diese Arbeit behandelt eine flexible Strategie für den hochvariablen Produktionsfall einer solchen Produktionsstätte. Der Algorithmus basiert auf einem detaillierten Fabriksimulationsmodell mit Rückgriff auf Realdaten. Neben synthetischen Testdaten wurde der Algorithmus auch anhand einer realen Fertigungsumgebung geprüft. Verschiedene Steuerungsregeln werden hierbei sinnvoll kombiniert und gewichtet. Wechselnde Anforderungen wie Linienbalance, Durchsatz oder Liefertermintreue können adressiert und optimiert werden. Mittels einer definierten Zielfunktion erlaubt die automatische Modellgenerierung eine Optimierung anhand des aktuellen Fabrikzustandes. Die Optimierung basiert auf einen genetischen Algorithmus für eine flexible und effiziente Lösungssuche. Die Strategie wurde mit Realdaten aus der Fertigung einer typischen hochvariablen geringvolumigen Halbleiterfertigung geprüft und analysiert. Die Analyse zeigt ein Verbesserungspotential von 5% bis 8% für die bekannten Performancekriterien wie Cycletime im Vergleich zu gewöhnlichen statischen Steuerungspolitiken. Eine prototypische Implementierung realisiert diesen Ansatz zur Nutzung in der realen Fabrikumgebung. Die Implementierung basiert auf der JAVA-Programmiersprache. Aktuelle Implementierungsmethoden erlauben den flexiblen Einsatz in der Produktionsumgebung. Neben der Fabriksteuerung wurde die Möglichkeit der Reduktion von Messoperationszeit (auch bekannt unter Sampling) unter gegebenen Randbedingungen einer hochvariablen geringvolumigen Fertigung untersucht und geprüft. Oftmals ist aufgrund stabiler Prozesse in der Fertigung die Messung aller Lose an einem bestimmten Produktionsschritt nicht notwendig. Diese Arbeit untersucht den Einfluss dieses gängigen Verfahrens aus der Massenfertigung für die spezielle geringvolumige Produktionsumgebung. Die Analysen zeigen insbesondere in Ausnahmesituationen wie Anlagenausfällen und Kapazitätsengpässe einen positiven Effekt, während der Einfluss unter normalen Produktionsbedingungen aufgrund der hohen Produktvariabilität als gering angesehen werden kann. Nach produktiver Einführung in einem typischen Vertreter dieser Halbleiterfabriken zeigten sich schnell positive Effekte auf die Fabrikperformance als auch eine breite Nutzerakzeptanz. Das implementierte System wurde Bestandteil der täglichen genutzten Werkzeuglandschaft an diesem Standort

User friendly progress reporting system for construction projects

Construction is a dynamic and fragmented industry which has many interacting stakeholders’ represented by either individuals or organizations who are involved in a common project for a certain period of time. The simple form for the stakeholders consists of owner, consultant and contractor. As such, construction industry is depending on appointing a consultant, by the owner, to carry out the design of the project and then assigning a contractor, which is responsible to allocate a team to build and give them the sufficient tool to communicate and report. Each party shall formulate its organization chart for such project and assign a project manager on top of hierarchy of this chart. For all involved stakeholders, managing construction projects requires controlling its running schedule and cost comparing to the planned ones. In order to do that, project managers for each stakeholders need periodical reports that represent the status of the project to predict any potential problems and consider taking the necessary measures on the proper time to maintain the project course and budget. Most problems in the construction industry are referred to communication and reporting problems. The links between the different stakeholders have to be built on a robust communication and reporting system that allows to acquire precise, simple and accurate information. Lack in communication and reporting system, shall result in having a misleading information which consequently lead to wrong decisions. This research tackles the consequences of poor communication and reporting systems and provide some tips to have an effective one. Followed by, describing the current used reporting techniques where their suitability for use is assessed. Furthermore, a user friendly reporting technique is presented where the used data in developing the technique was acquired from literature study and structured interviews with 29 professional expert in construction industry. The proposed technique aims to integrate the communication process to allow project managers to acquire a simple overview about the projects progress and obstacles. The suggested interface is pointing to achieve the balance between simplicity, accuracy and effectiveness with a reasonable cost. Through simple tables and graphs, it gives a quick overview for the managers to understand the status of their projects for each activity and the assigned resources, evaluate the progress through the key performance indicators, predict the problems at early stage and appraise the project’s cash flow to act in a proactive mode not in a reactive one. The proposed interface depends on acquiring on-spot information from each of the project team members about the progress and incurred costs for all project activities through user friendly interface which is designated with its simplicity. Formerly, the acquired information for the progress shall be translated to comprehensive progress report which allows the project manager to understand the status of the project. The offered technique is suitable to be used in any of stakeholders firms as long as it has projects enclose planned activities associated with costs. However, the contractor perspective is considered in this study

Triage and treatment of strategic and operational problems in a semiconductor equipment consumables manufacturing company

Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.Includes bibliographical references (leaf 98).The company studied in this internship project supplies consumable copper components to the semiconductor equipment industry. Growing in this industry has been much more difficult than the company's original 1995 business plan had anticipated. Customers' aversion to change, intolerance for failure, and competitive reactions (some customers are also competitors) have all taken their toll on the company's ability to establish itself in this industry. The business is currently under pressure from corporate management to improve its financial performance, which has not met corporate goals since the company's inception. It has been unable to win production volume orders from customers; thus economies of scale in production have been unachievable. Further, the delivery performance of several suppliers and the aggregate supply chain are very poor. Although the company's technology is still being developed to accommodate some unique wafer fabrication process challenges, the semiconductor industry has little tolerance for product test failures. Several such failures have degraded the company's reputation as a viable solution provider for some fab (semiconductor fabrication facility) processes. There is no systematic process for order fulfillment in place and many important tasks frequently fall between the cracks. The company is also constrained for both personnel and financial resources. A significant portion of the limited personnel resources is spent tending to emergency situations and performing repetitive tasks. Lack of personnel resources, inefficient business processes, and corporate pressures for performance improvements have necessitated a short-term business focus. Thus many strategic and fundamental issues have become secondary. This work took a triage perspective on the problems defined above. The internship began with a problem definition phase. Interviews were scheduled with each of the company's employees to define the internal perspective on the company's situation. Then, the author immersed himself in the company's value chain and took on temporary responsibility for processing several customer orders through the order fulfillment process. The author's perspective was combined with those of the internal players and a list of priority problems was created for further investigation. A common theme throughout all interviews and experiences in the value chain was a lack of understanding of costs. It quickly became clear that the organization did not have an accurate means of calculating either overhead costs or the costs of an anodizing operation across product families. In light of the recent corporate pressures to improve financial performance, this area was chosen early as one on which to focus the author's efforts. Several cost models were developed and iterated to provide insights on several cost issues. In particular, models were developed to predict the effects of demand mix and volume upon product costs, the ability of the company's anodizing facility to produce forecasted or hypothetical volume levels, the impact of reductions in anodizing line downtime downtime, and the implications for cost and relationships of a proposed contract with a new anodizing supplier. Several of these models became tools for the business to utilize in improving the accuracy of the cost estimates it uses in quoting. Other issues were much more ambiguous. In particular, the various members of the company had described the extraordinary test results achieved by their product relative to the product currently available in the market. Yet, in over three years, the company had been unable to penetrate the market with significant volumes in production fab processes. Each employee seemed to have a different opinion as to why the organization had failed to be successful. These inconsistencies drove the author to design and administer a voice-of-the-customer (VOC) survey with several different customers. The goal of the survey was to get all employees on the same page and to provide customer opinions as to what the most critical areas for improvement were. The survey uncovered several large problems. Some of the problems were too technical and lengthy in time commitment to justify further work during this project. One area that was rated as being an important problem by customers was delivery performance. In fact, this problem would become much more of a roadblock as the company got closer to winning contracts to provide consumables to production fab processes, especially given the generally high expectations of this industry and the ongoing fab efforts to reduce inventories. Delivery performance was found to be significantly affected by machining supplier delivery performance, anodizing supplier delivery performance, and internal order processing systems (or lack thereof). Each of these areas was investigated and diagnosed. Supplier discussions and surveys were critical to understanding the root cause of the supplier delivery problems.by James Ryan Griffith.S.M

Production Scheduling

Generally speaking, scheduling is the procedure of mapping a set of tasks or jobs (studied objects) to a set of target resources efficiently. More specifically, as a part of a larger planning and scheduling process, production scheduling is essential for the proper functioning of a manufacturing enterprise. This book presents ten chapters divided into five sections. Section 1 discusses rescheduling strategies, policies, and methods for production scheduling. Section 2 presents two chapters about flow shop scheduling. Section 3 describes heuristic and metaheuristic methods for treating the scheduling problem in an efficient manner. In addition, two test cases are presented in Section 4. The first uses simulation, while the second shows a real implementation of a production scheduling system. Finally, Section 5 presents some modeling strategies for building production scheduling systems. This book will be of interest to those working in the decision-making branches of production, in various operational research areas, as well as computational methods design. People from a diverse background ranging from academia and research to those working in industry, can take advantage of this volume

Modeling, design and scheduling of computer integrated manufacturing and demanufacturing systems

This doctoral dissertation work aims to provide a discrete-event system-based methodology for design, implementation, and operation of flexible and agile manufacturing and demanufacturing systems. After a review of the current academic and industrial activities in these fields, a Virtual Production Lines (VPLs) design methodology is proposed to facilitate a Manufacturing Execution System integrated with a shop floor system. A case study on a back-end semiconductor line is performed to demonstrate that the proposed methodology is effective to increase system throughput and decrease tardiness. An adaptive algorithm is proposed to deal with the machine failure and maintenance. To minimize the environmental impacts caused by end-of-life or faulty products, this research addresses the fundamental design and implementation issues of an integrated flexible demanufacturing system (IFDS). In virtue of the success of the VPL design and differences between disassembly and assembly, a systematic approach is developed for disassembly line design. This thesis presents a novel disassembly planning and demanufacturing scheduling method for such a system. Case studies on the disassembly of personal computers are performed illustrating how the proposed approaches work

Air traffic management in the South East European countries. Current situation and prospects

This paper deals with the Air Traffic Management (ATM) situation in the South East Europe (SEE) countries. The current status indicates that the SEE air space users require increased capacity, higher flexibility and improved cost efficiency. On the other hand, some of these countries were in a war situation a few years ago, and now they are seeking a regional cooperation to ensure regional stability and prosperity towards their integration to the European Union. The paper starts with a description of the cooperation schemes, already in operation in the area. Then the attempt to converge the ATM of the region towards the EU Single European Sky is investigated. The FABA (Functional Airspace Block Approach), a European Union (EU) initiative, applied in the SEE is presented in detail. In the continuation, the paper reports on the definition phase of the SEE FABA initiative, which is to provide a well founded basis for the reorganisation of the SEE air space into FAB’s. It is concluded that the FAB solution stemming from the EU Single European Sky policy is feasible, highly beneficial and necessary for the SEE region development

Optimizing inventory levels using financial, lifecycle and forecast variance data

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; in conjunction with the Leaders for Manufacturing Program at MIT, 2007.Includes bibliographical references (leaves 47-48).Significant inventory write-offs have recently plagued ATI Technologies, a world leader in graphics and media processors. ATI's product-centric culture has long deterred attention from supply chain efficiency. Given that manufacturing lead time exceeds customer order lead time for its semiconductors, ATI relies heavily on their demand forecasting team to instigate supply chain activities. The PC business unit forecasting team translates market information into product-line forecast and also sets finished goods inventory levels intended to offset demand uncertainty. Today's inventory decisions are made in response to customer escalations, often ignoring financial implications. To add necessary rigor when setting these inventory levels, this thesis presents a model using wafer and unit cost, profit margin, product lifecycle stage and historical forecast error to categorize products into inventory risk levels. The resultant risk levels become a critical input to monthly demand-supply meetings with marketing, operations and senior executives - the outcome of which are wafer orders and assembly and test plans at the world's largest contract foundries and subcontractors. Finally, the 2006 acquisition of ATI by Advanced Micro Devices (AMD) offers unforeseen flexibility, scale and challenges to the outsourced semiconductor supply chain.by Irene S. Hwang.S.M.M.B.A