• Journal of Welding and Joining
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• v.29 no.6
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• pp.65-70
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• 2011

The effect of flip chip bonding parameters on formation of intermetallic compounds (IMCs) between Au stud bumps and Sn-3.5Ag solder was investigated. In this study, flip chip bonding temperature was performed at $260^{\circ}C$ and $300^{\circ}C$ with various bonding times of 5, 10, and 20 sec. AuSn, $AuSn_2$ and $AuSn_4$ IMCs were formed at the interface of joints and (Au, Cu)$_6Sn_5$ IMC was observed near Cu pad side in the joint. At bonding temperature of $260^{\circ}C$, $AuSn_4$ IMC was dominant in the joint compared to other Au-Sn IMCs as bonding time increased. At bonding temperature of $300^{\circ}C$, $AuSn_2$ IMC clusters, which were surrounded by $AuSn_4$ IMC, were observed in the solder joint due to fast diffusivity of Au to molten solder with increased bonding temperature. Bond strength of Au stud bump joined with Sn-3.5Ag solder was about 23 gf/bump and fracture mode of the joint was intergranular fracture between $AuSn_2$ and $AuSn_4$ IMCs regardless bonding conditions.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.1
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• pp.19-26
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• 2007

This study was focused on the feasibility of ultrasonic bonding of Au flip chip bumps for a practical complementary metal oxide semiconductor (CMOS) image sensor with electroplated Au substrate. The ultrasonic bonding was carried out with different bonding pressures and times after the atmospheric pressure plasma cleaning, and then the die shear test was performed to optimize the ultrasonic bonding parameters. The bonding pressure and time strongly affected the bonding strength of the bumps. The Au flip chip bumps were successfully bonded with the electroplated Au substrate at room temperature, and the bonding strength reached approximate 73 MPa under the optimum conditions.

• Journal of Technologic Dentistry
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• v.31 no.4
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• pp.15-23
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• 2009

The aim of this study was to evaluate the bond strength of using a Au bonding agent applied on cp-Ti and nonprecious metal-gold-ceramic system. Metallic frameworks(diameter: 5mm, height: 20mm)(N=56, n=7per group) cast in Ni-Cr alloy, Co-Cr alloy and cp-Ti were obtained using acrylic templates and airborne particle abraded with $110{\mu}m$ aluminum oxide. Au bonding agent was applied on wash opaque firing as intermediate layer. SEM and SEM/EDS line profile were performed on the cutting the cross-section of the metal substrate-porcelain with intermediate Au coating. Groups were tested using shear bond strength(SBS) testing at 0.5mm/min. The mean SBS values for the ceramic-Au layer-metal combination were significantly higher than those ceramic-metal combination. While ceramic-Au layer-cp-Ti combinations failed to increase bond strength instead of using a titanium bonding porcelain. The appication of using Au intermediate layer significantly improve the bond strength combination with metal-ceramic system.

• Journal of Technologic Dentistry
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• v.24 no.1
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• pp.65-71
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• 2002

This study was performed to observe the microhardness change of the surface and the bonding strength between the porcelain and alloy specimens in order to investigate the effects of appended indium, tin and copper on interfacial properties of Au-Pd-Ag alloys. The hardness of castings was measured with a micro-Vicker's hardness tester. The interfacial shear bonding strength between alloy specimen and fused porcelain was measured with a mechanical testing system(MTS 858.20). The microhardness of Au-Pd-Ag alloy was increased by adding indium and tin, but not increased by adding copper. The shear bonding strength of Au-Pd-Ag-Sn alloy and Au-Pd-Ag-Cu alloy showed 87MPa, 57MPa. The higher concentration of adding elements showed the higher shear bonding strength.

• Journal of dental hygiene science
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• v.9 no.2
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• pp.153-160
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• 2009

The purposed of this study was to investigate the effect of Gold bonding agent as intermediate layer between metal substrate and ceramic coating. Gold bonding agent used to seal off any surface porosity, to mask the greyish color of the metal, and to provide an underlying bright golden hue to the ceramic coverage. The adhesion between metal substrate and ceramic is related to diffusion of oxygen during ceramic firing. The oxide layer produced on non-precious alloy anti titanium was considered to have a potentially adverse effect on metal-ceramic bonding. The oxidation characteristics of titanium and non-precious alloys are the main problem. Every group were divided into test and control groups. Control groups are carried out process of degassing for product oxide layer. Au coating was applied on each Ni-Cr, Co-Cr alloys and cp-Ti specimens with difference surface condition or degassing. Specimens surfaces and cutting plane was characterized by SEM/EDS. Results suggested that Au coating is effective barriers to protect metal oxidation during ceramic firing.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.367-372
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• 2020

As packaging processes for atomic gyroscope vapor cells, the glass tube tip-off process, anodic bonding, and paste sealing have been widely studied. However, there are stability issues in the alkali metal which are caused by impurity elements and leakage during high-temperature processes. In this study, we investigated the applicability of a vapor cell low-temperature packaging process by depositing Au on a Pyrex cell in addition to forming an Au-Sn thin film on a cap to cover the cell, followed by laser irradiation of the Au/Au-Sn interface. The mechanism of the thin film bonding was evaluated by XRD, while the packaging reliability of an Ne gas-filled vapor cell was characterized by variation of plasma discharge behavior with time. Furthermore, we confirmed that the Rb alkaline metal inside the vapor cell showed no color change, indicating no oxidation occurred during the process.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.4
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• pp.79-85
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• 2007

This study was focused on the feasibility of ultrasonic bonding of Au stud flip chip bumps on the flexible printed circuit board (FPCB) with three different surface finishes: organic solderability preservative (OSP), electroplated Au and electroless Ni/immersion Au (ENIG). The Au stud flip chip bumps were successfully bonded to the bonding pads of the FPCBs, irrespective of surface finish. The bonding time strongly affected the joint integrity. The shear force increased with increasing bonding time, but the 'bridge' problem between bumps occurred at a bonding time over 2 s. The optimum condition was the ultrasonic bonding on the OSP-finished FPCB for 0.5 s.

• Journal of Welding and Joining
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• v.22 no.3
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• pp.62-68
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• 2004

The strip Au bumps are bonded using longitudinal ultrasonic far the electronic package. Au bumps on the chip and substrate are aligned in a crossed shape, and the ultrasonic is imposed on the chip to form the solid-state bond between the Au bumps. Deformed bump shapes are calculated using the finite element method, and the bond strength is measured experimentally. The crossed strip Au bumps are deformed similar to the saddle, which provides larger contact surface area and higher friction force. Compared with the previous bonding method between the Au bump and planar pad, higher bond strength is obtained using the crossed strip bumps.

• Journal of dental hygiene science
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• v.9 no.4
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• pp.405-412
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• 2009

The purpose of this study investigated the effect of Au coating on adhesion between porcelain matrix and metal substructure interface. Titanium, Ni-Cr alloy and Co-Cr alloy are well known as proper metal for the dental restorations. The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. However, adhesion between dental alloys and porcelain is related to diffusion of oxygen during ceramic firing. The excessive oxidized layers make hard adhesion between dental alloy and ceramic. Ni-Cr and Co-Cr specimens were divided into test and a control group and Titanium specimens were divided into three test groups and a control group. Each group had 20 specimens. The adhesion characteristics of porcelain and metal with Au coating layer and without Au coating layer were observed with scanning electron microscopy(SEM). The adhesion was evaluated by a biaxial flexure test and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that Au coating layer is effective barrier to diffuse oxide layer completely protect non-precious alloys from oxidation during the porcelain firing. The SEM photomicrographs of cross-section specimens showed a smooth interface between Au coating layer and metals and porcelain which suggested proper chemical bonding, and no gap, porosity were observed. The mode of failure was mainly adhesive for Ti tested specimens, but mixed failures with adhesive and cohesive were observed in Ni-Cr and Co-Cr specimens. The adhesion between non-precious metals and porcelain would not be improved by Au coating agent. However, It is suggested that the continuous study is required further investigation and development.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.2 s.43
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• pp.49-57
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• 2007

Au-Sn solder alloy were deposited in multilayer and co-sputtered film by rf-magnetron sputter and the composition control and analysis were studied. For the alloy deposition condition, each components of Au or Sn were deposited separately. On the basis of pure Sn and Au deposition, the deposition condition for Au-Sn solder alloy were set up. As variables, the substrate temperature, the rf-power, and the thickness ratio were used for the optimum composition. For multilayer solder alloy, the roughness and the composition of solder alloy were controlled more accurately at the higher substrate temperature. In contrast, for co-sputtered solder, the substrate temperature influenced little to the composition, but the composition could be controlled easily by rf-power. In addition, the co-sputtered solder film mostly consisted of intermetallic compound, which formed during deposition. The compound were confirmed by XRD. Without flux during bonding of solder alloy film on leadframe, the adhesion strength were measured. The maximum shear stress was $330(N/mm^2)$ for multilayer solder with Au 10wt% and $460(N/mm^2)$ for co-sputtered solder with Au 5wt%.