Min-Hsiung Hung

A Novel Virtual Metrology Scheme for Predicting CVD Thickness in Semiconductor Manufacturing

In an advanced semiconductor fab, online quality monitoring of wafers is required for maintaining high stability and yield of production equipment. The current practice of only measuring monitor wafers may not be able to timely detect the equipment-performance drift happening in-between the scheduled measurements. This may cause defects of production wafers and, thereby, raise the production cost. In this paper, a novel virtual metrology scheme (VMS) is proposed for overcoming this problem. The proposed VMS is capable of predicting the quality of each production wafer using parameters data from production equipment. Consequently, equipment-performance drift can be detected promptly. A radial basis function neural network is adopted to construct the virtual metrology model. Also, a model parameter coordinator is developed to effectively increase the prediction accuracy of the VMS. The chemical vapor deposition (CVD) process in semiconductor manufacturing is used to test and verify the effectiveness of the proposed VMS. Test results show that the proposed VMS demonstrates several advantages over the one based on back-propagation neural network and can achieve high prediction accuracy with mean absolute percentage error being 0.34% and maximum error being 1.15%. The proposed VMS is simple yet effective, and can be practically applied to construct the prediction models of semiconductor CVD processes.

A processing quality prognostics scheme for plasma sputtering in TFT-LCD manufacturing

A novel quality prognostics scheme (QPS) for plasma sputtering in TFT-LCD manufacturing processes is proposed. The QPS consists of a conjecture model and a prediction model. The conjecture model can use processing parameters and sensor data to estimate the processing quality (sputtering thickness) in real time. This conjecture function is also called virtual metrology. On the other hand, the prediction model is capable of predicting the processing quality of the next-lot glasses. Neural networks and weighted moving average algorithms are applied to construct the QPS. In particular, a reliance index is developed such that online evaluation of whether the conjecture results of the QPS are trustworthy or not is possible. For increasing the accuracy of the QPS, a self-searching mechanism is designed to automatically search the best set of parameters and functions used by the conjecture and prediction algorithms for cases that the processing properties vary or the recipe changes. Also, an auto-adjusting mechanism is developed for tuning the system parameters of the QPS and bringing the conjecture accuracy within an acceptable bound. Thorough tests using normal and abnormal processing data on one set of plasma sputtering equipment in a TFT-LCD plant show that the values of the mean absolute percentage error of both the conjecture and the prediction results are less than 2%, which validates the effectiveness of the proposed QPS.

Torque optimization schemes for kinematically redundant manipulators

One of the important applications for the resolution of redundant manipulators is torque optimization, due to the fact that the actuators used for driving a manipulator have finite power ratings. Nevertheless, not many algorithms have been proposed to accomplish this objective. A survey of the existing local torque optimization control schemes is given in this article. It will be shown that all of them either encounter instability problems for long trajectories or fail in certain cases. For remedying these problems, the authors present the Minimum Velocity Norm (MVN) method, which is the most common approach for kinematic redundancy resolution and has never been adopted for torque optimization by other researchers. Simulation results show that the simple MVN method is moderate for short movements and is stable for long movements. Also, the MVN method can be applied to cases that may not be accomplished by some other approaches. Therefore, the MVN method is better than the other existing approaches for torque optimization.

Development of an e-Diagnostics/Maintenance framework for semiconductor factories with security considerations

Abstract In recent years, the concept of e-Diagnostics and e-Maintenance is proposed in the semiconductor industry. By using Internet and information technologies, e-Diagnostics and e-Maintenance intend to provide equipment specialists with the remote capabilities of connectivity, manipulation, configuration, performance monitoring, and data collection and analysis on equipment to achieve the goal of promptly diagnosing, repairing, and maintaining equipment. In this paper, new-generation information software technologies and object-oriented technologies, such as Web Services, XML signature, XML encryption, UML, etc. are used to develop an e-Diagnostics/Maintenance framework with security considerations. The proposed framework can achieve the automaton of diagnostic processes and the integration of diagnostics and maintenance information under a secure communication infrastructure.

Development of a web-services-based e-diagnostics framework for semiconductor manufacturing industry

Recently, the emerging Web-Services technology has provided a new and excellent solution to the data integration among heterogeneous systems. A Web-Services-based e-diagnostics framework (WSDF) is proposed. It can achieve the automation of diagnostic processes and diagnostics information integration for semiconductor equipment. First, the system framework and the system component model are designed. Then, the object-oriented analysis and design of system components are accomplished. In particular, for the purpose of code reuse, several common functions, such as simple object access protocol communication, universal description discovery and integration registration, security mechanism, data exchange mechanism, and local database access, are built into a generic component called Web-Service agent. By inheriting the Web-service agent, other system components can be constructed and have these common functions. In addition, a unified authentication-service mechanism and a safe network connection are also designed in the framework. WSDF is intended to support the e-diagnostics functions defined by International SEMATECH. It is believed that WSDF can be applied to construct e-diagnostics systems for the semiconductor manufacturing industry.

Intelligent prognostics system design and implementation

This paper proposes an intelligent prognostics system JPS) for semiconductor and TFT-LCD manufacturing. The IPS comprises several generic embedded devices (GEDs) and remote clients. The GED can be easily embedded into various types of equipment to acquire equipment engineering data and meet the specification requirements of Interface A for supporting semiconductor industry equipment engineering capabilities. Furthermore, the GED has an open-standard application interface offering pluggable and customized intelligent applications. With this feature, the intelligent applications can be distributed and localized, releasing the factory network burden and enhancing equipment reliability and processing quality. This paper also develops two typical pluggable applications: the predictive maintenance scheme (PMS) for detecting equipment faults and the virtual metrology scheme (VMS) for conjecturing equipment-processing quality. Integrating the PMS into the IPS and the VMS into the IPS are, respectively, accomplished using the conveyor equipment and the sputtering equipment in a TFT-LCD factory. These two illustrative examples clearly demonstrate that IPS is versatile, configurable, and effective.

A ZigBee-Based Power Monitoring System with Direct Load Control Capabilities

ZigBee is a wireless networking standard that has characteristics of low power consumption, having up to 65535 device nodes, and low data rates. It is suitable to be applied in many home and industrial applications that could operate in harsh radio environments and in isolated locations. In this paper, a novel ZigBee-based powering monitoring system (PMS) is proposed. In particular, the proposed PMS utilizes ZigBee for wireless communication, DSP (Digital Signal Processing) for realtime power parameters computation, and Web Services for constructing the communication infrastructure among distributed systems across networks. A paradigm system for monitoring campus power consumptions is constructed and experimented to validate the effectiveness of the proposed PMS. The testing results show that the functions of the proposed PMS comply with the designed objectives. The paradigm PMS also demonstrates good performances in direct load control and warning message transmission. This work possesses novelty for first time integrating ZigBee, DSP, and Web Services technologies to develop PMS, and can be a useful reference for future developments of PMS.

A generic embedded device for retrieving and transmitting information of various customized applications

A generic embedded device (GED) that can be installed to various kinds of information equipment, such as manufacturing equipment, portal servers, automatic guided vehicles, etc., is successfully developed In this work. GED is equipped with an embedded real-time operating system and several software modules to retrieve, collect, and manage equipment data. In particular, the communication management module of GED can transmit and receive data to/from remote clients via both wired and wireless networks. Moreover, GED has an object-oriented application interface that flexibly enables GED to add-in or update any customized application. Three typical communication mechanisms, namely the standard processes of exception notification, periodic inspection, and data inquiry are built in GED. As such, GED is able to handle a variety of customized applications, such as monitoring, detection, diagnostics, and prognostics of various kinds of information equipment. We believe that GED possesses the potentiality of information acquisition and transmission so that it can assist all kinds of information equipment to reach the goal of equipment-to-system (E2S) communication and facilitate the maintenance tasks.

Development of an Ease-of-Use Remote Healthcare System Architecture Using RFID and Networking Technologies

The study aims to provide an ease-of-use approach for senior patients to utilize remote healthcare systems. An ease-of-use remote healthcare system (RHS) architecture using RFID (Radio Frequency Identification) and networking technologies is developed. Specifically, the codes in RFID tags are used for authenticating the patients’ ID to secure and ease the login process. The patient needs only to take one action, i.e. placing a RFID tag onto the reader, to automatically login and start the RHS and then acquire automatic medical services. An ease-of-use emergency monitoring and reporting mechanism is developed as well to monitor and protect the safety of the senior patients who have to be left alone at home. By just pressing a single button, the RHS can automatically report the patient’s emergency information to the clinic side so that the responsible medical personnel can take proper urgent actions for the patient. Besides, Web services technology is used to build the Internet communication scheme of the RHS so that the interoperability and data transmission security between the home server and the clinical server can be enhanced. A prototype RHS is constructed to validate the effectiveness of our designs. Testing results show that the proposed RHS architecture possesses the characteristics of ease to use, simplicity to operate, promptness in login, and no need to preserve identity information. The proposed RHS architecture can effectively increase the willingness of senior patients who act slowly or are unfamiliar with computer operations to use the RHS. The research results can be used as an add-on for developing future remote healthcare systems.

Development of a Web-Services-based remote monitoring and control architecture

In this paper, a remote monitoring and control architecture is developed. The architecture consists of a Web-services-based monitoring and control gateway (WSMCG), distributed Ethernet-ready I/O modules, safety detection modules, Web cameras, and networks. It can not only provide general functions of remote monitoring and control but also possess the mechanism of actively detecting appliances abnormal power consumption and ensuring appliance safety. This research incorporates the newest network-related technologies with the concept of ensuring appliance safety for developing remote monitoring and control systems. The research results are with novelty and high practicability. It is believed that the developed technologies and concepts can be applied in constructing new-generation remote monitoring and control systems.