E.B. Hakim, J. Fink, S.M. Tam, P. McCluskey and M. Pecht
For many years, the concern over the use of plastic encapsulated microcircuits(PEMs) has been their capability to survive in harsh environments over a long termwith continuous or…
Abstract
For many years, the concern over the use of plastic encapsulated microcircuits (PEMs) has been their capability to survive in harsh environments over a long term with continuous or intermittent operation. The issues centred around operational life limitation, due to failure mechanisms associated with internal corrosion, wires and wire bonds, and surface effects, It has now been conclusively demonstrated that best commercial practices will ensure that PEMs made using best commercial materials, processes, and quality techniques will permit devices to perform reliably in the most severe environments. Missile systems are low volume production items, which use relatively few microcircuits. They are required to operate for very short times after being unpowered (dormant) for very long times (10 to 20 years) and exposed to humidity, temperature cycle, and mechanical shock. This paper will address reliability concerns and provide data from studies which were performed to determine if PEMs could survive such long‐term unbiased applications. These studies include analysis of PEMs (some date coded 1968) from inventory or various storage locations and from applications where the electronic modules containing PEMs were stored for 10‐12 years in various environments. Regardless of the storage conditions, the significant factor is that these early vintage commercial grade PEMs, without screening or incoming inspection, survived assembly and extended storage.
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Michael Pecht, Keith Rogers and Andre Fowler
Non‐woven laminates have begun to gain recognition in the electronics industry because they are generally thinner and flatter than woven laminates. This study characterizes the…
Abstract
Non‐woven laminates have begun to gain recognition in the electronics industry because they are generally thinner and flatter than woven laminates. This study characterizes the mechanical and thermo‐mechanical properties of non‐woven, randomly dispersed, short fiber laminates, and identifies potential failure mechanisms which must be addressed in the design and utilization of printed circuit boards using non‐woven technology.
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Michael Pecht and Chung‐Shing Lee
Summarizes the flat panel display (FPD) industry outside of Japan, with a focus on advances in Korea and Taiwan. Discusses the major manufacturers in each country as well as their…
Abstract
Summarizes the flat panel display (FPD) industry outside of Japan, with a focus on advances in Korea and Taiwan. Discusses the major manufacturers in each country as well as their current status. Concludes with a brief discussion on the future outlook of the FPD market.
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Michael Pecht and Dave Humphrey
The paper presents an alternative solution to address part obsolescence. This paper discusses approaches to solve part obsolescence including an uprating approach. This paper also…
Abstract
Purpose
The paper presents an alternative solution to address part obsolescence. This paper discusses approaches to solve part obsolescence including an uprating approach. This paper also describes the methods to uprate parts, and demonstrates the practical application of the uprating approach in the form of a case study.
Design/methodology/approach
This paper has been written to provide an understanding of the uprating approach to mitigate the problems caused by part obsolescence. The paper discusses the challenge faced due to part obsolescence, the temperature ratings for electronic parts, the uprating methods and finally explains the use of uprating to mitigate part obsolescence in the form of a case study. The part being uprated is a microcontroller unit used in many avionics applications. The case study describes a particular use of uprating and the return on investment.
Findings
Based on the uprating approach, it was discovered that for the particular application, the commercially available plastic quad flat pack microcontroller could be used as a substitute for the “military” ceramic BGA version, which was discontinued by the manufacturer. It was discovered that there would be no problem with the commercial part's quality or reliability for the particular application. Parametric tests showed no evidence of instability of electrical characteristics over the uprated temperature range. There was substantial return on investment due to the use of uprated parts.
Practical implications
This paper can help electronics manufactures deal with part obsolescence. This paper demonstrates the practicality of uprating parts. Uprating can save companies money by reducing the need for life‐time buys, substitution of parts and even redesign.
Originality/value
The paper provides an alternative approach to address the problem of part obsolescence. This paper shows that proper uprating leads to cost saving while continuing to provide reliable service.
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Abstract
This paper presents a study to determine the extent to which delamination at the die to encapsulant interface affects the package moisture content, and electrical failures when subjected to unbiased temperature‐humidity testing. Moisture absorption experiments showed that the presence of delamination did not significantly after the measurable moisture absorption characteristics of packages. Reliability testing indicated that although delamination is generally thought of as a reliability risk, it may not be a sufficient condition to promote damage in packages under dormant storage conditions. Experimental results showed no parametric or functional failures (or visible degradation) in packages with 100% die surface delamination after 1000 hours of unbiased testing at 140°C/85%RH.
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Keith L. Rogers and Michael G. Pecht
To show how the use of conductor spacings below 4 mil in printed wiring boards (PWBs) can introduce an unanticipated failure mechanism, leading to current leakage and short…
Abstract
Purpose
To show how the use of conductor spacings below 4 mil in printed wiring boards (PWBs) can introduce an unanticipated failure mechanism, leading to current leakage and short circuit failure.
Design/methodology/approach
The tests in this study were conducted in accordance with IPC‐TM‐650 2.6.25, using boards designed with conductor spacings between plated through holes (PTHs) ranging from 6 to 3 mil and from 8 to 3 mil between PTHs and ground planes. The board types and conductor spacings were selected to include current and future printed circuit board fabrication technology.
Findings
For PWBs that may be used in harsh environments where the relative humidity and temperature may approach those of the test environments, even for relatively short periods of time, spacings of 4 mil or less in the materials tested may not be appropriate. However, it is unlikely that the 85°C and 85 percent RH conditions are the minimum conditions to induce this failure mechanism. More tests at lower temperatures and relative humidity combinations should be conducted to evaluate conditions at which this type of failure begins.
Originality/value
The value of the paper lies in that the tests show that the IPC industry standard for conductive filament formation (CFF) testing of PTH‐PTH conductor spacings of 4 mil or less, at 85°C/85 percent RH can introduce a CFF variant failure mechanism, and therefore, may need to be modified to ensure that the test conditions accelerate the CFF mechanism and not other low resistance paths.
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Keith Rogers, Craig Hillman, Michael Pecht and Suzanne Nachbor
A defective printed circuit board assembly that exhibited excessive current leakage was examined to determine the responsible failure mechanisms. Observation of the failure site…
Abstract
A defective printed circuit board assembly that exhibited excessive current leakage was examined to determine the responsible failure mechanisms. Observation of the failure site (determined electrically) by optical and electron microscopy revealed an area in the circuit board where debonded fiber bundles bridged a plated‐through‐hole (PTH) to a copper plane. This phenomenon is highly suggestive of conductive filament formation.
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Increasing board densities, decreasing spacing between holes and features and the growing requirement for printed circuit boards to perform in high temperature/high humidity…
Abstract
Increasing board densities, decreasing spacing between holes and features and the growing requirement for printed circuit boards to perform in high temperature/high humidity environments have led to renewed concerns about possible reliability problems caused by the growth of Conductive Anodic Filaments (CAF). To date, there has been a lack of information on standardized test procedures and failure analysis methods for various types of prepregs and laminates.This paper introduces a standard test vehicle design and discusses suitable testing, failure analysis and board manufacturing methods. It also includes the requirements for CAF resistance and there is a discussion of material benchmarking tests with some preliminary results from this testing. These methods should be applicable to boards used in all market segments, including high density interconnect, and automotive applications.
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Du Sig Choi, Paul Michell and Dayananda Palihawadana
This paper aims to discuss the profiles of Korean chaebols involved in global electronics
Abstract
Purpose
This paper aims to discuss the profiles of Korean chaebols involved in global electronics
Design/methodology/approach
The research was conducted among 132 of their Korean suppliers, with linked in‐depth interviews with chaebol managers. From an initial set of literature‐based variables, factor analysis is used to generate six chaebol characteristics, which are then correlated with four chaebol‐supplier relationship outcomes.
Findings
“Decision making” and “social exchange”, in particular, are found to correlate positively with all four chaebol‐supplier relationship outcome measures, relationship satisfaction, performance, cooperation and conflict resolution. “Partnership” is associated positively with three of these outcomes, and “strategy‐longevity” with relationship satisfaction. The chaebols' “structure‐control” and “leadership” are not found to be predictors of successful relationship outcomes as measured in this study. A combination of higher quality, lower cost products with linkages to a foundation of decision making, social exchange, partnership and strategy‐longevity appears to be a potent mix for global players.
Originality/value
The paper provides the underpinnings of the marketing strategy and component strategy profiles of a number of major Korean multinationals in the belief that they would inform western relationship marketing strategies.
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Ryspek Usubamatov, Abdul Rahman Riza and Muhamad Nasir Murad
The purpose of this paper is to study and perform a system analysis of car assembly line processes, to show productivity losses and their causes, and to derive a mathematical…
Abstract
Purpose
The purpose of this paper is to study and perform a system analysis of car assembly line processes, to show productivity losses and their causes, and to derive a mathematical model of the productivity rate of the assembly line.
Design/methodology/approach
The paper performs productivity calculations based on data obtained from the assembly processes of a car cabin and shows the losses of productivity and their causes. The equations of the assembly line productivity rate and the optimal number of assembly stations are derived by the criterion of maximum productivity.
Findings
The paper provides a productivity diagram that illustrates various productivity losses and their associated causes together with the output of car assembly processes. The diagram is based on proposed mathematical calculations. It is a derived analytical model of the productivity rate of the assembly line as a function of the assembly technology, number of stations, reliability of machine and mechanisms, as well as managerial and organizational factors.
Research limitations/implications
Solutions to decrease the productivity losses of the assembly line are given based on the results of the study and analysis of the assembly processes in real industrial environments.
Practical implications
The paper includes implications of the methodology used in the investigation of the productivity of the assembly line, and the equation of the productivity rate, which allows for the calculation of maximum productivity and the optimal number of assembly stations.
Originality/value
The paper presents a method of analysis of the productivity and a mathematical model for calculating the productivity rate of the assembly line. The results of the research are obtained from a real industrial environment.