1,721,019 research outputs found
The effects of the degree of cure of anisotropic conductive films (ACFs) on the contraction stress build-up of ACFs and ACF joints stability for chip-on-flex (COF) applications
No full textNon-Conductive Films (NCFs) with multi-functional epoxies and silica fillers for reliable NCFs Flip Chip on Organic Boards (FCOB)
No full textThe effects of the degree of cure of anisotropic conductive films (ACFs) on the contraction stress build-up of ACFs and ACF joints stability for ACF FlipChip interconnection
No full textEffect of conductive particle properties on the reliability of anisotropic conductive film for Chip-On-Glass (COG) applications
No full textEffect of conductive particle properties on the reliability of anisotropic conductive film for chip-on-glass applications
No full textThis paper describes how the material properties of conductive particles in anisotropic conductive films (ACFs) affect the electrical conductivity and the reliability of ACF interconnections for chip-on-glass (COG) applications. For the conductive particles, Au/Ni-coated polymer particles with a 5-mu m diameter were used. Two different types of conductive particles were characterized with respect to their mechanical and electrical properties, such as ball hardness, recovery behavior, and electrical resistance. In addition, two ACFs were fabricated in the form of a double-layered structure, in which the thickness of the ACF and a nonconductive film (NCF) layer were optimized to have as many conductive particles as possible on the bump after COG bonding. The electrical contact resistance of an ACF interconnection in a COG structure depends mainly on the electrical properties of conductive particles in the ACF. The electrical reliability of an ACF interconnection in a COG structure also depends more on the electrical properties than the mechanical properties of conductive particles under a high-temperature and humid condition. Conductive particles with a lower electrical resistance, higher mechanical hardness, and lower recovery rate show better reliability than conductive particles with a higher electrical resistance, lower mechanical hardness, and higher recovery rate. Cross-sectional scanning electron microscopic (SEM) pictures of a COG interconnection show the deformation of two different conductive particles after the reliability tests. The ACF interconnections in the edge or corner of a driver IC show less reliable joints due to high absorption of moisture
Nanofiber anisotropic conductive adhesives (ACAs) for ultra fine pitch chip-on-film (COF) packaging
No full textSite assessment and evaluation of spatial earthquake ground motion of Kyeongju
No full textThe earthquake hazard has been evaluated for 10 km x 10 km area around Kyeongju. The ground motion potentials were determined based on equivalent linear analysis by using the data obtained from in situ and laboratory tests. In situ tests include 16 boring investigations, 4 crosshole, 12 downhole, 26 spectral analysis of surface waves tests, and in the laboratory, resonant column tests were performed. The peak ground accelerations range between 0.141g and 0.299g on collapse level earthquake and between 0.050g and 0.120g on operation level earthquake, respectively, showing the high potential of amplification in the deep alluvial layer in Kyeongju area. Distribution maps of site amplification for the peak acceleration, amplification factors (F-a and F-v) and dominant site period of Kyeongju are constructed using geographic information system tools. The amplification factor based on the Korean seismic design guide underestimated the motion in short range and overestimated the motion in mid-period range in Kyeongju. The importance of site-specific analysis and the need for the improved site characterization method are introduced. (C) 2002 Elsevier Science Ltd. All rights reserved
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
Wafer level package using pre-applied Anisotropic Conductive Films (ACFs) for flip-chip interconnections
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