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Transparent and conductive ZnO 50 nm/Au 8 nm/ZnO 50 nm tri-layer films were deposited on poly-imide films by radio frequency (RF) and direct current (DC) magnetron sputtering at room temperature, and then the effect of electron irradiation on the crystallization, electrical resistivity and optical properties of the films was considered with X-ray diffraction, UV-visible spectrometer, Atomic force microscope and Hall measurement system. All the films were deposited at a fixed sputtering power, Ar gas flow rate, and distance between target and substrate, while the post-deposition electron irradiation energy was varied from 300 to 900 eV. The electron irradiated films exhibited a flatter surface than the as deposited films that were not electron irradiated, and the XRD patterns also revealed that the electron irradiated films had larger grain sizes than that of as deposited films. The films electron irradiated at 900 eV also showed a higher visible transmittance of 79.8% and a lower sheet resistance of 56.0 Ω/□. Post-deposition films electron irradiated at 900 eV showed a higher figure of merit of 1.86×10-3 Ω-1 than that of the as deposited film of 1.29×10-3 Ω-1. The optical band gap was also enhanced by electron irradiation. The films electron irradiated at 900 eV showed a higher optical band gap of 4.07 eV.

Transparent and conductive Ti-doped In2O3 (TIO)/Ag/Ti-doped In2O3 (TAT) multilayer films were deposited on colorless poly imide (CPI) substrates by direct current (DC) and radio frequency (RF) magnetron sputtering at room temperature. During deposition the thickness of both the top and bottom TIO layer was fixed at 30 nm, while the thickness of the Ag interlayer was varied, to 5, 10, and 15 nm, to enhance the optical, electrical and mechanical properties of the films. In the XRD analysis the TIO films did not show any characteristic peaks in the diffraction pattern. The 10 nm thick Ag inter layer showed some characteristic peaks of Ag (111), (200), (220) and (311), respectively, and the grain size of the Ag interlayer enlarged as Ag thickness increased. To investigate the most efficient Ag interlayer thickness, a figure of merit (FOM) based on the opto-electrical performance of the transparent conducting films was compared. The films with a 10 nm thick Ag interlayer exhibited a higher FOM of 1.71 × 10-2 Ω-1 than the other films. When the radius of the film's curvature was reduced to 1.7 mm, the TIO single layer films showed a 13 times increase in sheet resistance, while the TAT (30/10/30 nm) films showed an insignificant change in sheet resistance. From the observed results, it was concluded that the Ag interlayer in the TAT multilayer films enhanced the opto-electrical performance of the films and also acted as a potent bridge which assured the high flexibility endurance of the films.

A new microporous Zr(IV)-based metal–organic framework (MOF) containing 4,4′,4″,4‴-(9,9′-spirobi[fluorene]-2,2′,7,7′-tetrayl)tetrabenzoic acid (Spirof-MOF) was synthesized, characterized, and size-controlled for the adsorption and decomposition of a nerve agent simulant, dimethyl 4-nitrophenylphosphate (DMNP). Spirof-MOF showed a hydrolysis half-life (t1/2) of 7.5 min to DMNP, which was confirmed by using in situ 31P NMR spectroscopy. Additionally, size-controlled Spirof-MOFb (∼1 μm) exhibited a half-life of 1.8 min and 99% removal within 18 min for DMNP. The results show that Spirof-MOF is a new active material in removing nerve agent simulants by adsorption and hydrolytic decomposition.

The effect of displacement rate and intermetallic compound (IMC) growth on the shear strength of electroplated Sn-2.5Ag (in wt.%) flip chip solder with Cu under-bump metallization (UBM) were investigated after multiple reflows. Cu"6Sn"5 IMC was formed at the interface after one reflow. After five reflows, two different IMC layers, consisting of a scallop-shaped Cu"6Sn"5 phase and a planar Cu"3Sn phase, and their thicknesses increased with increasing reflow number up to 10. The shear strengths peaked after four reflows, and then decreased with increasing reflow number. Increasing displacement rate increased the shear force. The tendency toward brittle fracture characteristics was intensified with increasing displacement rate and reflow number.

The traditional ball shear test is not suitable for evaluating joint reliability under drop loading, since the applied test speeds, usually lower than 5 mm/s, are well below the impact velocity applied to the solder joint in a drop test. The present study expands recently reported research by investigating the effect of thermal aging on the joint strength and fracture mode of Sn-3.0Ag-0.5Cu ball grid arrays during high-speed shear testing, with a shear height of 50 μm and a shear speed ranging from 0.01 m/s to 3 m/s. The test specimens were aged at 393 K for 1000 h. After reflow, a (Ni,Cu)3Sn4 intermetallic compound (IMC) layer was observed at the solder/Ni-P interface and the thickness of the IMC layer was increased through the aging process. The shear strength increased with increasing shear speed. The fracture surface of the solder joints showed three different fracture modes according to the shear speed and aging time. The fracture mode changed from ductile fracture to brittle fracture with increasing shear speed.

The failure behaviors of flip chip solder joints under various loading conditions of the high-speed shear test (H-SST) were investigated with an experimental and non-linear 3-dimensional finite element modeling study. The solder composition used in this study was Sn -3.0 Ag -0.5 Cu ( in wt .%). The shear forces were far greater by H-SST than by low-speed shear test (L-SST). The shear force further increased with increasing shear speed, mainly due to the high strain-rate sensitivity of the solder alloy. Brittle interfacial fractures were more easily achieved by H-SST, especially at the higher shear speed. This was discussed in terms of the relationship between the strain-rate and work-hardening effect and the resulting stress concentration at the interfacial regions

In this study, the electrodes on the flexible printed circuit board (FPCB) and rigid PCB (RPCB) were bonded by a thermo-compression bonding. The surface finishes on Cu electrodes of RPCB and FPCB were electroless Ni/immersion Au (ENIG) and electroless Ni/electroless Pd/Immersion Au (ENEPIG), respectively. In order to determine the optimum bonding conditions, a 90° peel test of the FPCB-RPCB joint was conducted. The optimum bonding pressure and time were 2.04 MPa and 5 s at 260°C, respectively. Thin and uniform (Ni,Cu) 3 Sn 4 intermetallic compound (IMC) layers formed at both ENEPIG(FPCB)/Sn-3.0Ag-0.5Cu/ENIG(RPCB) interfaces. We successfully accomplished the thermo-compression bonding for a reliable FPCB-RPCB connection by using a Pb-free Sn-3.0Ag-0.5Cu interlayer.