We studied a growth behavior of Intermetallic compounds(IMCs) during solder bumping with two reflow methods. Ti(50 nm), Cu(), Au(50 nm) and Ti(50 nm) thin films were deposited on /Si wafer using the DC magnetron sputtering system as the under bump metallization(UBM). And the thick Cu bumps and thick Sn bumps were fabricated on UBM by electroplating. Sn bumps were reflowed in RTA(Rapid Thermal Annealing) system and convection reflow oven. When RTA system was used, reflow was possible without using flux and IMC thickness formed in the solder interface was thinner than that of a convectional method.

Microstructure and contact resistance of the Au-Sn solder joints were characterized after flip-chip bonding of the Au/Sn bumps processed by successive electrodeposition of Au and Sn. Microstructure of the Au-Sn solder joints, formed by flip-chip bonding at for 30 sec, was composed of the +AuSn lamellar structure. The interlamellar spacing of the +AuSn structure increased by reflowing at for 3 min after flip-chip bonding. While the Au-Sn solder joints formed by flip-chip bonding at for 30 sec exhibited an average contact resistance of 15.6 /bump, the Au-Sn solder joints reflowed at for 3 min after flip-chip bonding possessed an average contact resistance of 15.0 /bump.

Thermal annealing and electromigration test were performed at and conditions, respectively, in order to compare the growth kinetics of intermetallic compound(IMC) in Cu pillar bump. The quantitative interfacial adhesion energy with annealing was measured by using four-point bending strength test in order to assess the effect of IMC growth on the mechanical reliability of Cu pillar bump. Only was observed in the Cu pillar/Sn interface after reflow. However, formed and grew at Cu pillar/ interface with increasing annealing and stressing time. The growth kinetics of total() IMC changed when all Sn phases in Cu pillar bump were exhausted. The complete consumption time of Sn phase in electromigration condition was faster than that in annealing condition. The quantitative interfacial adhesion energy after 24h at was while it was before annealing. Therefore, the growth of IMC seem to strongly affect the mechanical reliability of Cu pillar bump.

Reliability and performance in metal gate/high-k device with multiple gate dielectrics were investigated. MOSFETs with a thin layer on a thermal Si02 dielectric as gate dielectrics exhibit excellent mobility and low interface trap density. However, the distribution of threshold voltages of stack devices were wider than those of and single layer devices due to the penetration of Hf and/or intermixing of with underlying . The results of TZDB and SILC characteristics suggested that a certain portion of layer reacted with the underlying thick layer, which in turn affected the reliability characteristics.

To develop the MEMS cap bonding process without cavity formation, we electroplated Cu/Sn rim structures and measured the bonding characteristics for the Cu/Sn rims of width. As the effective device-mounting area ratio decreased and the failure strength ratio increased for wider Cu/Sn rim, these two properties were estimated to be optimized for the Cu/Sn rim with 150 width. Complete bonding was accomplished at the whole interfaces of the Cu/Sn packages with the rim widths of 25 and 50 . However, voids were observed locally at the interfaces with the rim widths larger than 100 . Such voids were formed by local non-contact between the upper and lower rims due to the surface roughness of the electroplated Sn.

Thermoelectric properties of the n-type Bi-Te and the p-type Bi-Sb-Te films were measured and the growth behaviors of the electrodeposited Bi-Te and Bi-Sb-Te nanowires were characterized. Filling ratios of 81% and 77% were obtained for electrodeposition of the Bi-Te and the Bi-Sb-Te nanowires, respectively, into the nano pores of 200 nm-diameter of an alumina template. A thermoelectric module, composed of the Bi-Te nanowires and the Bi-Sb-Te nanowires was processed by electrodeposition, and a resistance value of was measured between the Ni electrodes formed on the Bi-Te nanowires and the Bi-Sb-Te nanowires of the module.

In this paper, wetting and interfacial reaction properties for low Ag containing Sn-Ag-Cu Pb-free solder alloy, i.e., Sn-0.3Ag-0.7Cu were investigated and compared with those of Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu. Melting behavior and stress-strain curves of some Sn-xAg-xCu alloys were also measured using a differential scanning calorimeter(DSC) and a tensile test machine, respectively. In order to enhance insufficient wetting properties of Sn-0.3Ag-0.7Cu alloy, the improvement of wetting properties were analyzed by applying fluxes containing higher content of halide or indium adding of 0.2wt.% into the solder alloy. It was concluded that the small addition of indium is more effective for the improvement of wettability in low temperature range of than applying flux containing higher content of halide.

In this paper, white polymer light emitting diodes(WPLEDs) were fabricated and investigated the electrical and optical properties for the prepared devices. ITO(indium tin oxide) and PEDOT:PSS [poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)] as anode and hole injection materials, PFO [poly(9,9-dioctylfluorene)] and MEH-PPV [poly(2-methoxy-5(2-ethylhe xoxy)-1,4-phenylenevinyle)] were used as the light emitting host and guest materials, respectively. The LiF(lithium flouride) and Al(aluminum) were used electron injection materials and cathode materials. Finally, the WPLED with structure of ITO/PEDOT:PSS/PFO:MEH-PPV/LiF/Al was fabricated. The prepared WPLED showed white emission with CIE coordinates of (x=0.36, y=0.35) at the applied voltage of 9V. The maximum current density and luminance were about at 13V, respectively. And the maximum current efficiency was 0.37 cd/A at in luminance.

The mechanical shear strength of BGA(Ball Grid Array) solder joints under high impact loading was investigated. The Sn-37Pb solder balls with a diameter of were placed on the pads of FR-4 substrates with ENIG(Electroless Nickel Immersion Gold) surface treatment and reflowed. For the High Temperature Storage(HTS) test, the samples were aged a constant testing temperature of for up to 250h. After the HTS test, high speed shear tests with various shear speed of 0.01, 0.1, 1, 3 m/s were conducted. intermetallic compound(IMC) layer was observed at the solder/Ni-P interface and thickness of IMC was increased with aging process. The shear strength increased with increasing shear speed. The fracture surfaces of solder joints showed various fracture modes dependent on shear speed and aging time. Fracture mode was changed from ductile fracture to brittle fracture with increasing shear speed.

The mechanical properties of Ni-Fe alloy were varied with the current type, current density and bath conditions such as concentrations and temperature. The effect of electroplating parameters on the surface hardness, mechanical strength, residual stress and wear properties were investigated. The mechanical properties of electrodeposits with PC plating is superior to those with DC plating. Ni-Fe electrodeposits with PC has approximately 50% lower residual stress than that of DC plating. The tensile strength of PC electroplated specimen was 15% higher than that of DC electroplated specimen. The wear resistance of PC specimen was 30% improved relative to that of DC specimen.

The reliability of leaded and lead-free solders of BGA type packages on a printed circuit board was investigated by employing the standard drop test and 4-point bending test. Tested solder joints were examined by optical microscopy to identify associated failure mode. Three-dimensional finite element analysis(FEM) with ANSYS Workbench v.11 was carried out to understand the mechanical behavior of solder joints under the influence of bending or drop impact. The results of numerical analysis are in good agreement with those obtained by experiments. Packages in the center of the PCB experienced higher stress than those in the perimeter of the PCB. The solder joints located in the outermost comer of the package suffered from higher stress than those located in center region. In both drop and bending impact tests, the lead-free solder showed better performances than the leaded solders. The numerical analysis results indicated that stress and strain behavior of solder joint were dependent on various effective parameters.

The interface microstructure of Sn-3.5Ag/Cu joint was modified by electroplating varying amount of Zn on Cu UBM. As the amount of Zn dissolved in Sn-3.5Ag solder increased with the electroplating Zn thickness, Cu-Sn IMCs such as and were replaced by Zn-containing IMCs such as and , which increased the drop reliability of solder joints significantly. When the amount of Zn dissolved in solder was about 3.8wt%, drop resistance was best due to the effective suppression of Cu-Sn IMC and voids at the interface.

The one and two pair of oxide modules for high temperature thermoelectric power generation were fabricated with (p-type) and (n-type) on substrate. For the optimizing of the design process, contact resistance was derived from the results of the one pair modules, and then the resistance of two pair modules were calculated to use the derived data. Those values were compared with the measured values for the optimizing of this design process. The resistance of calculated and measured two pairs modules was 0.956 and 1.110 Q =833 K, respectively, the difference of resistance was about 0.15 . From the result, proposed design process is effective for high temperature thermoelectric oxide modules fabrication.

The thin films doped with Pd and CNT as gas sensor were prepared by spin coating and then the gas response of these films were evaluated under concentration and operating temperature of . It was found that the sensor resistance was increased with exposure and concentration. The 3wt% Pd doped sample showed a sensitivity of 26.5 which was 10 times higher than that of pure . And also the sensitivity of CNT doped sample increased with CNT content and it had 72 when 0.225 wt% of CNT was added under 5ppm concentration.