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Abstract: The existence of defects in the corresponding interfaces can gradually degrade the interfacial adhesion when the flip chip package is exposed to the high temperature and humidity. This study used the fuzzy controller to stabilize both the moisture weight gain and adhesion strength together for the button shear test specimen. Parameters design, although based on the Taguchi method, can optimize the performance characteristic through the setting of process parameters and can reduce the sensitivity of the system performance to sources of variation. However, most published Taguchi applications to date have been concerned with the optimization of a single performance characteristic only. For example, it is only concerned a single performance characteristic with the optimization of the adhesion strength or the moisture gain weight individually. In this study, the control rules of the fuzzy controller were formed using the authors’ experience and knowledge of the IC packaging process. The control parameters to be tuned were the membership functions. Therefore, the controller’s performance depended on the membership functions. The fuzzy controller combined Taguchi parameter design, which makes the control performance insensitive to the operating condition changes and noise was used to determine the membership functions. [Copyright &y& Elsevier]

Abstract: The mechanisms underlying age-related loss of muscle and bone tissue are poorly understood but are thought to involve changes in sex hormone status, physical activity, and circulating levels of inflammatory cytokines. This study attempts to develop an animal model useful for evaluating these mechanisms in vivo. Male C57BL/6 mice were included for study at 3, 6, 12, 18, 24, and 29 months of age. Endocortical mineralizing surface, serum leptin, body weight, and percentage of body fat all increased between 6 and 12 months of age as activity level declined. Serum levels of the inflammatory marker IL-6 increased significantly after 12 months of age, following the observed increase in body weight and percent body fat. Hindlimb muscle mass declined significantly between 18 and 24 months of age, both absolutely and relative to total body mass, with a further decline (∼15%) between 24 and 29 months. Loss of muscle mass after 18 months of age was accompanied by a significant increase in bone resorption, as indicated by serum pyridinoline cross-links, and a significant decrease in fat mass, serum leptin, bone strength, bone mineral density, and vertical cage activity. No significant changes in serum testosterone with aging were detected in the mice, as levels were essentially constant between 6 and 29 months. Our data show that mice lose a significant amount of muscle and bone tissue with age, and this loss of musculoskeletal tissue is accompanied by a drop in serum leptin and preceded by a significant decrease in physical activity. [Copyright &y& Elsevier]

Abstract: The CTE and CHE mismatch between materials in a thin PBGA package is primarily attributed to the warpage which occurs when the package is being mounted on to a PCB, especially when the moisture content reaches a specified value. In this paper, the stability equations for the warpage in a PBGA package without the solder balls being subjected to hygro-thermal loading, by modeling it as an initially perfect/imperfect composite plate, have been developed. The analytical closed-form solutions are found and used to compute not only the critical moisture content but also the warpage occurring before the critical loads are reached. The buckling of the PBGA package, at the solder reflow peak temperature, occurs when the theoretical moisture content reaches 0.259–0.283wt.%. This theoretical critical moisture content accurately predicts the experimental critical moisture content (0.25–0.30wt.%) derived from our previous work. The results, from comparison between theoretical and experimental critical moisture content, indirectly indicate that the PBGA package has little imperfection. However, the large initial imperfect structure of the package does not easily reach the buckling stage because of moisture absorption. In addition to this, the structure of the PBGA package before buckling become stress-free at the moisture level of 0.077wt.% and at room temperature during moisture conditioning. [Copyright &y& Elsevier]

The coefficient of temperature expansion mismatch between materials in a thin plastic ball grid array package is primarily attributed to the warpage when mounting the package to a printed circuit board, especially when the moisture concentration reaches a specified value. The influence of variations in storage conditions on warpage was investigated in this paper. The effects of the reflow parameters on warpage were also examined. Taguchi’s method was implemented for experimental design and data analyses. A critical relative moisture absorption between 0.25% and 0.30% was found for a considerable warpage response. [Copyright &y& Elsevier]