This paper aims to present an adaptation of digital image correlation (DIC) to the electronics industry for reliability assessment of electronic packages. Two case studies are…
Abstract
Purpose
This paper aims to present an adaptation of digital image correlation (DIC) to the electronics industry for reliability assessment of electronic packages. Two case studies are presented: one for warpage measurement of a micro-electro-mechanical system (MEMS) package under different temperature conditions and the other for the measurement of transient displacements on the surface of a printed circuit board (PCB) assembly under free-fall drop conditions, which is for explaining the typical camera setup requirement and comparing among different boundary conditions by fastening methods of PCB.
Design/methodology/approach
DIC warpage measurements on a small device, such as a MEMS package, require a special speckle pattern. A new method for the creation of speckle patterns was developed using carbon coating and aluminum evaporative deposition. To measure the transient response on the surface of a PCB during a free-fall impact event, three-dimensional (3D) DIC was integrated with synchronized stereo-high speed cameras. This approach enables the measurement of full-field displacement on the PCB surface during a free-fall impact event, contrary to the localized information that is obtained by the conventional strain gage and accelerometer method.
Findings
The authors suggest the proposed patterning method to the small-sized microelectronics packages for DIC measurements. More generally, the idea is to have a thin layer of the dark or bright color of the background and then apply the white or black colored pattern, respectively, so that the surface has high contrast. Also, to achieve a proper size of speckles, this paper does not want to expose the measuring objects to high temperatures or pressures during the sample preparation stage. Of course, it seems a complicated process to use aluminum evaporator, carbon coater and electroformed mesh. However, the authors intend to share one of the solutions to achieve a proper pattern on such small-sized electronic packages.
Originality/value
3D DIC technique can be successfully implemented for the measurement of micro-scale deformations in small packages (such as MEMS) and for the analysis of dynamic deformation of complex PCB.
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The purpose of this paper is to assess the thermo-mechanical reliability of a solder bump with different underfills, with the evaluation of different underfill materials. As there…
Abstract
Purpose
The purpose of this paper is to assess the thermo-mechanical reliability of a solder bump with different underfills, with the evaluation of different underfill materials. As there is more demand in higher input/output, smaller package size and lower cost, a flip chip mounted at the module level of a board is considered. However, bonding large chips (die) to organic module means a larger differential thermal expansion mismatch between the module and the chip. To reduce the thermal stresses and strains at solder joints, a polymer underfill is added to fill the cavity between the chip and the module. This procedure has typically, at least, resulted in an increase of the thermal fatigue life by a factor of ten, as compared to the non-underfilled case. Yet, this particular case is to deal with a flip chip mounted on both sides of a printed circuit board (PCB) module symmetrically (solder bump interconnection with Cu-Pillar). Note that Cu-Pillar bumping is known to possess good electrical properties and better electromigration performance. The drawback is that the Cu-Pillar bump can introduce high stress due to the higher stiffness of Cu compared to the solder material.
Design/methodology/approach
As a reliability assessment, thermal cyclic loading condition was considered in this case. Thermal life prediction was conducted by using finite element analysis (FEA) and modified Darveaux’s model, considering microsize of the solder bump. In addition, thermo-mechanical properties of four different underfill materials were characterized, such as Young’s modulus at various temperatures, coefficient of temperature expansion and glass transition temperature. By implementing these properties into FEA, life prediction was accurately achieved and verified with experimental results.
Findings
The modified life prediction method was successfully adopted for the case of Cu-Pillar bump interconnection in flip chip on the module package. Using this method, four different underfill materials were evaluated in terms of material property and affection to the fatigue life. Both predicted life and experimental results are obtained.
Originality/value
This study introduces the technique to accurately predict thermal fatigue life for such a small scale of solder interconnection in a newly designed flip chip package. In addition, a guideline of underfill material selection was established by understanding its affection to thermo-mechanical reliability of this particular flip chip package structure.
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This paper aims to develop an estimation tool for warpage behavior of slim printed circuit board (PCB) array while soldering with electronic components by using finite element…
Abstract
Purpose
This paper aims to develop an estimation tool for warpage behavior of slim printed circuit board (PCB) array while soldering with electronic components by using finite element method. One of the essential requirements for handheld devices, such as smart phone, digital camera, and Note-PC, is the slim design to satisfy the customers’ desires. Accordingly, the printed circuit board (PCB) should be also thinner for a slim appearance, which would result in decreasing the PCB’s bending stiffness. This means that PCB deforms severely during the reflow (soldering) process where the peak temperature goes up to 250°C. Therefore, it is important to estimate PCB deformation at a high temperature for thermo-mechanical quality/reliability after reflow process.
Design/methodology/approach
A numerical simulation technique was devised and customized to accurately estimate the behavior of a thin printed board assembly (PBA) during reflow by considering all components, including PCB, microelectronic packages and solder interconnects.
Findings
By applying appropriate constraints and boundary conditions, it was found that PBA’s warpage can be accurately predicted during the reflow process. The results were also validated by warpage measurement, which showed a fairly good agreement with one and another.
Research limitations/implications
For research limitations, there are many assumptions regarding numerical modeling. That is, the viscoplastic material property of solder ball is ignored, the reflow profile is simplified and the accurate heat capacity is not considered. Furthermore, the residual stress within the PCB, generated at PCB manufacturing process, is not included in this paper.
Practical implications
This paper shows how to calculate PBA warpage during the reflow process as accurately as possible. This methodology helps a PCB designer and surface-mount technology (SMT) process manager to predict a PBA warpage issue and modify PCB design before PCB real fabrication. Practically, this modeling and simulation process can be easily performed by using a graphical user interface (GUI) module, so that the engineer can handle an issue by inputting some numbers and clicking some buttons.
Social implications
In a common sense manner, a numerical simulation method can decrease time and cost in manufacturing real samples. This PCB warpage method can also decrease product development duration and produce a new product earlier. Furthermore, PCB is a common component in all the electronic devices. So, this PCB warpage method can have various applications.
Originality/value
Because of an economic advantage, the development of a numerical simulation tool for estimating the thin PBA warpage behaviour during reflow process was attempted. The developed tool contains the features of detailed modeling for electronic components and contact boundary conditions of the supporting rails in the reflow oven.
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The purpose of this paper was to study the combined effect of hygro and thermo-mechanical behavior on a plastic encapsulated micro-electro-mechanical systems (MEMS) package during…
Abstract
Purpose
The purpose of this paper was to study the combined effect of hygro and thermo-mechanical behavior on a plastic encapsulated micro-electro-mechanical systems (MEMS) package during the reflow process after exposed to a humid environment for a prolonged time. Plastic encapsulated electronic packages absorb moisture when they are subjected to humid ambient conditions.
Design/methodology/approach
Thus, a comprehensive stress model is established for a three-axis accelerometer MEMS package, with detailed considerations of fundamentals of mechanics such as heat transfer, moisture diffusion and hygro-thermo-mechanical stress. In this study, the mold compound is considered to be the most critical plastic material in MEMS package. Other plastic components of thin film materials can be disregarded due to their small sizes such as die attach and Bismaleimide Triazine (BT) core, even though they are also susceptible to moisture. Thus, only the moisture-induced properties of mold compound were obtained from the proposed experiments. From the desorption measurement after preconditioning at 85°C/85 per cent relative humidity (RH), the saturated moisture content and diffusivity were obtained by curve fitting the data to Fick’s equation. In addition, a new experimental setup was devised using the digital image correlation system together with a precision weight scale to obtain the coefficient of hygroscopic swelling (CHS) at different temperatures.
Findings
The experimental results show that the diffusion coefficient of mold compound material follows Arrhenius equation well. Also, it is shown that the CHS of mold compound increases as temperature increases. Experimentally obtained moisture properties were then used to analyze the combined behavior (thermo-hygro-mechanical) of fully saturated MEMS package during the reflow process using a finite element analysis (FEA) with the classical analogy method. Finally, the warpage and stresses inside the MEMS package were analyzed to compare the effects of hygroscopic, thermal and hygro-thermo-mechancal behaviors.
Originality/value
In this study, unlike the other researches, the moisture effects are investigated specifically for MEMS package which is relatively smaller in scale than conventional electronic packages. Also, as a conjugated situation, MEMS package experiences both humid and temperature during the moisture resistance test. Thus, major objective of this study is to verify stress state inside MEMS package during the reflow process which follows the preconditioning at 85°C/85 per cent RH. To quantify the stresses in the package, accurate information of material properties is experimentally obtained and used to improve modeling accuracy.
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Daehwan Kim, Joon Sung Lee, Wonseok (Eric) Jang and Yong Jae Ko
Marketers and brand managers are subject to reputational crises when their endorsers are involved in scandals. To effectively manage such crises, it is imperative to understand…
Abstract
Purpose
Marketers and brand managers are subject to reputational crises when their endorsers are involved in scandals. To effectively manage such crises, it is imperative to understand (1) the underlying mechanisms through which consumers process negative information surrounding morally tainted endorsers, and (2) how these mechanisms affect consumer behavior in the context of athlete scandals.
Design/methodology/approach
Drawing on attribution theory and the moral reasoning strategy framework, we investigate the impact of attribution on moral reasoning strategies, and the impact of such strategies on consumers' responses to scandalized athletes and endorsements.
Findings
Overall, our results demonstrate that the same scandal can be evaluated differently, depending on its information, including the consensus, distinctiveness, and consistency of the scandal. The results of Study 1 show that in the context of an on-field scandal, individuals engage in a sequential cognitive process in which they go through attribution, the choice of a moral reasoning strategy, and ultimately a response. The results of Study 2 reveal that in the context of an off-field scandal, attribution directly influences consumers' responses.
Originality/value
We extend the existing literature on the moral reasoning of athlete scandals by suggesting that attribution is a determinant of moral reasoning choice in the context of on-field scandals. We also extend the sports marketing and consumer behavior literature by suggesting that consumers' diverse reactions to athlete scandals depend on their attribution patterns and moral reasoning choices.
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Shintaro Sato, Yong Jae Ko, Daehwan Kim and Joon Sung Lee
The purpose of this research is to examine how pre-scandal associations and scandal types interactively influence consumer judgment and negative electronic word-of-mouth (eWOM).
Abstract
Purpose
The purpose of this research is to examine how pre-scandal associations and scandal types interactively influence consumer judgment and negative electronic word-of-mouth (eWOM).
Design/methodology/approach
Drawing from cognitive dissonance theory and associative memory network model, the online experiments (Amazon Mechanical Turk; Nexperiment 1 = 146 and Nexperiment 2 = 189) were conducted to examine the effects of positive pre-scandal associations (performance vs pro-social) and scandal types (performance-related vs -unrelated) on consumer blame and eWOM toward scandalized athletes. Data were analyzed by employing t-test (experiment 1), Multivariate Analysis of Covariance (MANCOVA) and PROCESS Model 8 (experiment 2) to test the hypotheses.
Findings
The findings highlight that positive pre-scandal association demonstrated both protecting and backfiring effects depending on the types of scandals. Specifically, when performance-related scandals emerged, consumers made more negative blame judgment of athletes with salient performance association, relative to pro-social association. Inversely, when performance-unrelated scandals occurred, athletes with salient pro-social association were more likely to be blamed. Regarding eWOM, consumers generate more negative eWOM when athletes with pre-performance associations are involved with performance-related scandals. This pattern of the result was not observed when athletes' pro-social association and performance-unrelated scandals were prominent.
Originality/value
The current work adds consumers' negative eWOM toward scandalized athletes to the literature as a predictor of how athletes' pre-scandal association with consumers and scandal types are related. The findings indicate that consumers feel greater dissonance and generate more negative eWOM when athletes' pre-scandal associations and scandal types are closely related.
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Anubhav A. Mishra and Megha Verma
This research paper explores customer experience (CX) among low-literate customers in organized retail environments. It integrates theories from customer literacy, CX and…
Abstract
Purpose
This research paper explores customer experience (CX) among low-literate customers in organized retail environments. It integrates theories from customer literacy, CX and patronage literature to understand CX comprehensively.
Design/methodology/approach
The study gathered data from 470 respondents using mall intercept and snowball sampling. Data analysis employed partial least squares (PLS) modeling.
Findings
The results indicate that all the dimensions do not have the same effect on CX. Answering calls for future research, the results establish CX's nomological validity by showing its positive influence on retail reputation, retail quality and satisfaction. However, it does not directly affect patronage but has an indirect influence through retail quality and satisfaction. Also, the authors conclude that retail quality and satisfaction are consequences of CX and not previously conceptualized proxies for it.
Research limitations/implications
Conducting primary research with low-literate customers (LLCs) has its own set of limitations that give rise to further research directions. While acknowledging limitations, the study suggests avenues for future research by surveying LLCs with an objective questionnaire, contributing to limited empirical research in this segment.
Practical implications
The findings highlight the multidimensional nature of CX. In summary, this research paper provides insights into CX dimensions and outcomes for LLCs in organized retail. It contributes to marketing literature, assisting retailers in improving CX and driving patronage across customer segments.
Originality/value
The paper contributes to marketing literature by studying LLCs, testing a comprehensive CX model, confirming antecedents in retail patronage and exploring reciprocal relationships in retailing.
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Jae‐Young Moon and Jun‐Sik Kwak
The purpose of this paper is to verify the difference in the effect of art‐parody and art‐infusion advertisements depending on the product type and regulatory focus, and to expand…
Abstract
Purpose
The purpose of this paper is to verify the difference in the effect of art‐parody and art‐infusion advertisements depending on the product type and regulatory focus, and to expand the boundary of research in the field.
Design/methodology/approach
The paper examines their effect depending on product type and regulatory focus through two experiments. One is the effect of art‐parody and art‐infusion advertisements by product type and the other is the effect of art‐parody and art‐infusion advertisements by regulatory focus.
Findings
Art‐infusion is more effective than art‐parody for utilitarian products in terms of message credibility and brand attitude except for purchase intention although there is no difference between the two types for hedonic products. Participants with promotion focus favor art‐parody advertisement, while participants with prevention focus favor art‐infusion advertisement in terms of cognitive attitude toward advertisement.
Research limitations/implications
This study is conducted as a part of research on art infusion, which is in the primitive stage of development. Therefore, it shall be possible to extend the boundary of research by applying a variety of marketing theories in the future.
Originality/value
The results of this paper imply that the advertising technique must vary depending on the type of focus the target customer values.
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Yongjae Kim, Kitae Yim and Yong Jae Ko
This study develops and tests a theoretical research model delineating the relationships between consumers' patriotism and their response to patriotic advertising and the…
Abstract
This study develops and tests a theoretical research model delineating the relationships between consumers' patriotism and their response to patriotic advertising and the advertised brand, and examines if the research model has the same pattern across different sporting events. Structural Equation Modeling is employed to test the model by using data collected from three different sporting event contexts. The results provide empirical evidence of the positive influence of consumers' patriotism on attitudes towards patriotic advertising and brands in sporting event contexts. A direct effect of patriotism on sports event involvement is found in international mega-sporting events but not in a domestic (or national) sporting event.