Browsing by Author "Wu, Chia Huang"

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An improved measure of quality loss for notching processes
(1970-01-01)
Wu, Chia Huang
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Hsu, Ya Chen
;
Pearn, Wen Lea
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工業工程與管理學系
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Department of Industrial Engineering and Management
Nowadays, electronic products are progressively becoming thinner, lighter, and more convenient for people to use. Printed circuit boards, and especially integrated circuit (IC) substrates, are among the essential component of these products. The IC substrate not only protects circuits, fixes lines, and conducts heat, but is also the critical component that provides signal connectivity between the chip, the printed circuit boards, and other crucial parts during the packaging process. The process capability indexC(pm)is commonly used to assess the product quality loss for decision making in modern semiconductor packaging manufacturing. For high-definition products, packaging processes often have very strict quality requirements and thus the quality inspection procedure is time-consuming and complicated. Therefore, because of the limitation of manpower and capacity of the inspection instruments, the collected sample for quality assessment may be with small to moderate sample sizes. In this paper, we introduce an unbiased estimator forC(pm)and provide a step-by-step parametric bootstrap procedure for obtaining a composite lower confidence bound onC(pm). To compare with the approaches discussed in the literature, numerical simulations are conducted under various process parameter settings. The results show that for small to moderate sample sizes, the proposed method applying the unbiased estimator has more accurate coverage rates than the existing methods. At the end of this paper, an application of quality loss assessment in notching processes is demonstrated.
Analytic Solution to Product Acceptance Determination for Gold Bumping Process With Multiple Manufacturing Lines
(2013-11-01)
Pearn, Wen Lea
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Tai, Yu Ting
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Wu, Chia Huang
;
Chuang, Ching Ching
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工業工程與管理學系
In recent years, gold bumping process has been applied extensively for the package technology of liquid crystal display driver integrated circuit, which is an essential component in portable devices. Because the increasing requirement of high-definition display devices, the gold bumping process has become more difficult and it is requested to be of high quality with very low fraction of defectives. Unfortunately, conventional methods for product acceptance determination no longer work because any sample of reasonable size probably contains no defective gold bump product items. In addition, in the globally competitive manufacturing environment, gold bumping processes involving multiple manufacturing lines are quite common in the Science-Based Industrial Park in Hsinchu, Taiwan, because of economic scale considerations. In this paper, we provide analytical solutions to gold bump product acceptance determination, which provide both manufacturers and customers to reserve their own rights by compromising on a rule for gold bumping process with multiple manufacturing lines. For the convenience of inplant applications, we tabulate the number of required inspection units, the critical acceptance values for various manufacturer's risks and consumer's risks, and various number of manufacturing lines. For illustration purpose, a real application in a gold bumping factory, which is located in the Science-Based Industrial Park in Hsinchu, Taiwan, is included.
Estimating process capability index C-pk: classical approach versus Bayesian approach
(2015-07-03)
Pearn, Wen Lea
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Wu, Chin Chieh
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Wu, Chia Huang
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統計學研究所
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工業工程與管理學系
Process capability index C-pk has been the most popular one used in the manufacturing industry dealing with problems of measuring reproduction capability of processes to enhance product development with very low fraction of defectives. In the manufacturing industry, lower confidence bound (LCB) estimates the minimum process capability providing pivotal information for quality engineers to monitoring the process and assessing process performance for quality assurance. The main objective of this paper is to compare and contrast the LCBs on C-pk using two approaches, Classical method and Bayesian method.
Lower confidence bounds as precision measure for truncated processes
(2017)
Wu, Chia Huang
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Pearn, Wen Lea
;
Tai, Yu Ting
;
Lin, Pi Chuan
;
工業工程與管理學系
Process capability index C-p has been the most popular one used in the manufacturing industry to provide numerical measures on process precision. For normally distributed processes with automatic fully inspections, the inspected processes follow truncated normal distributions. In this article, we provide the formulae of moments used for the Edgeworth approximation on the precision measurement C-p for truncated normally distributed processes. Based on the developed moments, lower confidence bounds with various sample sizes and confidence levels are provided and tabulated. Consequently, practitioners can use lower confidence bounds to determine whether their manufacturing processes are capable of preset precision requirements.