6,271 research outputs found
Exothermic reaction induced eutectic Pb-Sn solder ball melting in the underfill curing process
No full textThe effects of exothermic heat generated during underfill curing on the integrity of the solder bumped package, which is an important issue for the package reliability, have been overlooked. In this study, theoretical exotherm of underfill materials during underfill curing has been calculated using a differential scanning calorimeter (DSC) at cure temperature range from 100 degreesC to 200 degreesC. The calculated exotherm was compared with the exotherm profile measured at the typical cure temperature. The effects of cure temperature, amount of underfill, and initial underfill curing temperature on the exotherm profile of underfill materials have been investigated.This work was
supported in part by the Center for Electronic Packaging Materials, Korea Science
and Engineering Foundation
Study on the Nano and Micro Surface Morphology Effects on Interfacial Strength of Adhesively Bonded Bi-materials
No full textFactors related to return to work following a work-oriented occupational therapy program for individuals with physical disabilities
No full textEffects of silica filler and diluent on material properties and reliability of nonconductive pastes (NCPs) for flip-chip applications
No full textIn this paper, thermomechanical and theological properties of nonconductive pastes (NCPs) depending on silica filler contents and diluent contents were investigated. And then, thermal cycling (T/C) reliability of flip chip assembly using selected NCPs was verified. As the silica filler content increased, thermomechanical properties of NCPs were changed. The higher the silica filler content was added, glass transition temperature (T-g) and storage modulus at room temperature became higher while coefficient of thermal expansion (CTE) decreased. On the other hand, theological properties of NCPs were significantly affected by diluent content. As the diluent content increased, viscosity of NCP decreased and thixotropic index increased. However, the addition of diluent deteriorated thermomechanical properties such as modulus, CTE, and T-g. Based on these results, three candidates of NCPs with various silica filler and diluent contents were selected and used as adhesives for reliability test of flip chip assemblies. T/C reliability test was performed by measuring changes of NCP bump connection resistance. Results showed that flip chip assembly using NCP with lower CTE and higher modulus exhibited better T/C reliability behavior because of reduced shear strain in NCP adhesive layer
UBM (Under Bump Metallization) study for Pb-free electroplating bumping: Interface reaction and electromigration
No full textThe authors would like to express sincere appreciations to
Herbert Reichl (Fraunhofer IZM) for the support of KAISTFraunhofer
IZM co-work program. Special thanks to Hans
Auer and Heinz Gloor (Unaxis Balzers) for the UBM
depostion and to J.H.Lee (Daeduck Electronics) for providing
test substrates. They also thank to J.H.Kim and H. Ezawa
(Toshiba) for helpful technical advising. This work was
supported by Center for Electronic Packaging Materials of
Korea Science and Engineering Foundation
Material properties of anisotropic conductive films (ACFs) and their flip chip assembly reliability in NAND flash memory applications
No full textIn this paper, the material properties of anisotropic conductive films (ACFs) and ACF flip chip assembly reliability for a NAND flash memory application were investigated. Measurements were taken on the curing behaviors, the coefficient of thermal expansion (CTE), the modulus, the glass transition temperature T-g), and the die adhesion strength of six types of ACF. Furthermore, the bonding processes of the ACFs were optimized. After the ACF flip chip assemblies were fabricated with optimized bonding processes, reliability tests were then carried out. In the pressure cooker test, the ACF with the highest adhesion strength showed the best reliability and the ACF flip chip assembly revealed no delamination at the chip-ACF interface, even after 96 h. In the high temperature storage test and the thermal cycling test, the reliability of the ACF flip chip assembly strongly depends on the Tg value of the ACF. In the thermal cycling test, in particular, which gives ACF flip chip assemblies repetitive shear stress, high value of CTE above T-g accelerates the failure rate of the ACF flip chip assembly. From the reliability test results, ACFs with a high T-g and a low CTE are preferable for enhancing the thermal and thermo-mechanical reliability. In addition, a new double-sided chip package with a thickness of 570 mu m was demonstrated for NAND flash memory application. In conclusion, this study verifies the ACF feasibility, and recommends the optimum ACF material properties, for NAND flash memory application. (C) 2008 Elsevier Ltd. All rights reserved
Internal stresses evolution of non conductive pastes (NCPs) and underfill materials for flip chip applications
No full textNano and Micro Scale Surface Morphology Effects on Adhesion Strength for CFRP/Aluminum Bi-material Interfaces
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