• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.798-802
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• 2002

Metallurgical studies on the bonded interlayer of directionally solidified Ni-base superalloy GTD111 joints were carried out during transient liquid phase bonding. The formation mechanism of solid during solidification process was also investigated. Microstructures at the bonded interlayer of joints were characterized with bonding temperature. In the bonding process held at 1403K, liquid insert metal was eliminated by well known mechanism of isothermal solidification process and formation of the solid from the liquid at the bonded interlayer were achieved by epitaxial growth. In addition, grain boundary formed at bonded interlayer is consistent with those of base metal. However, in the bonding process held at 1453K, extensive formation of the liquid phase was found to have taken place along dendrite boundaries and grain boundaries adjacent to bonded interlayer. Liquid phases were also observed at grain boundaries far from the bonding interface. This phenomenon results in liquation of grain boundaries. With prolonged holding, liquid phases decreased gradually and changed to isolated granules, but did not disappeared after holding for 7.2ks at 1473K. This isothermal solidification occurs by diffusion of Ti to be result in liquation. In addition, grain boundaries formed at bonded interlayer were corresponded with those of base metal. In the GTD-ll1 alloy, bonding mechanism differs with bonding temperature.

• 한국분말재료학회지
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• 제8권4호
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• pp.258-267
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• 2001

In this work, the conventional transient liquid phase(TLP) bonding was modified. An attempt was made of using a liquid phase sintered alloy, which will be a liquid phase coexisting with a solid phase at the bonding temperature, as an interlayer for bonding metals. With an aim of revealing the fundamental features of this modified TLP bonding, the kinetics concerned with the growth of solid particles and the isothermal solidification process in Fe-1.16wt%B and Fe-4.5wt%P interlayers for the bonding pure iron, as well as the morphological change of the solid particle, were investigated.

• Journal of Welding and Joining
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• 제21권2호
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• pp.82-88
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• 2003

The bonding phenomenon and mechanism in the transient liquid phase bonding(TLP Bonding) of directionally solidified Ni base superalloy, GTD-111 was investigated. At the bonding temperature of 1403K, liquid insert metal was eliminated by isothermal solidification which was controlled by the diffusion of B and Si into the base metal and solids in the bonded interlayer grew epitaxially from mating base metal inward the insert metal. The number of grain boundaries formed at the bonded interlayer was corresponded with those of base metal. The liquation of grain boundary and dendrite boundary occurred at 1433K. At the bonding temperature of 1453K which is higher than liquation temperature of grain boundary, liquids of the Insert metal were connected with liquated grain boundaries and compositions in each region mixed mutually. In Joints held for various time at 1453t phases formed at liquated grain boundary far from the interface were similar to those of bonded interlayer. With prolonged holding time, liquid phases decreased gradually and liquids of continuous band shape divided many island shape. But liquid phases did not disappeared after holding for 7.2ks at 1453k. Isothermal solidification process at the bonding temperature which is higher than the liquation temperature of the grain boundary was controlled by diffusion of Ti to be result in liquation than B or Si. in insert metal. (Received January 15, 2003)

• Journal of Welding and Joining
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• 제19권4호
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• pp.423-428
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• 2001

The bonding phenomena of Ni base single crystal superalloy. CMSX-4 during transient liquid phase(TLP) bonding was investigated using MBF-80 insert metal. Bonding of CMSX-4 was carried out at 1,373∼1,548K for 0∼19.6ks in vacuum. The (001) orientation of each test specimen was aligned perpendicular to the bonding interface. The dissolution width of base metal was increased when the bonding temperature and holding time were increased. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process. Borides were formed in the bonded layer during TLP bonding operation. The solid phase grew epitaxially into the liquid phase from substrates and single crystallization could be readily achieved during the isothermal solidification.

• 마이크로전자및패키징학회지
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• 제24권1호
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• pp.27-34
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• 2017

Recently, a demand in sustainable green technologies is requiring the lead free bonding for high power module packaging due to the environmental pollution. The Transient-liquid phase (TLP) bonding can be a good alternative to a high Pb-bearing soldering. Basically, TLP bonding is known as the combination of soldering and diffusion bonding. Since the low melting temperature material is fully consumed after TLP bonding, the remelting temperature of joint layer becomes higher than the operating temperature of the power module. Also, TLP bonding is cost-effective process than metal nanopaste bonding such as Ag. In this paper, various TLP bonding techniques for power semiconductor were described.

• 마이크로전자및패키징학회지
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• 제24권1호
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• pp.17-25
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• 2017

Recently, research and application for a power module have been actively studied according to the increasing demand for the production of vehicles, smartphones and semiconductor devices. The power modules based on the transient liquid phase (TLP) technology for bonding of power semiconductor devices have been introduced in this paper. The TLP bonding has been widely used in semiconductor packaging industry due to inhibiting conventional Pb-base solder by the regulation of end of life vehicle (ELV) and restriction of hazardous substances (RoHS). In TLP bonding, the melting temperature of a joint layer becomes higher than bonding temperature and it is cost-effective technology than conventional Ag sintering process. In this paper, a variety of TLP bonding technologies and their characteristics for bonding of power module have been described.

• Journal of Welding and Joining
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• 제25권3호
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• pp.64-71
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• 2007

The dissolution phenomenon of the solid phase powder and base metal by liquid phase insert metal during Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111(base metal) powder and the GNi3 (Ni-l4Cr-9.5Co-3.5Al-2.5B) powder was investigated. In case of the mixed powder contains modified GTD111 powder 50wt%, all of the powder was melted by liquid phase at 1423K. At the temperature between solidus and liquidus of GNi3, liquid phase penetrated into the boundary of the modified GTD111 powder and solid particle separated from powder was melted easily because area of reaction was increased. With increasing mixing ratio of the modified GTD111, it needed the higher temperature to melt all of the modified GTD111 powder. During Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111 50wt% and GNi3 50wt% as insert metal, width of the bonded interlayer was increased with increasing bonding temperature by reaction of the base metal and liquid phase in insert metal. Dissolution of the base metal and modified powder by liquid phase progressed all together and after all of the powder was melted nearly, the dissolution of the base metal occurred quickly.

• 한국분말재료학회지
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• 제9권3호
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• pp.189-198
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• 2002

In this work, transient liquid phase (TLP) bonding of Ni-Cr heat resisted cast alloy (HP) was investigated. And also the behaviors of the solid particles distributed in the interlayer during TLP bonding were investigated. The MBF-60 and solid particles (Ni, Fe, and $Al_2O_3$ powders respectively) added MBF-60 which will be a liquid phase coexisting with solid particles at the bonding temperature were used as insert metal. The effective and sound bonding was possible by spark plasma sinter-bonding due to the differences of electric resistance between base metal and liquid insert layer which creates high temperature region. During the isothermal solidification, $Al_2O_3$ particles and solid particles of liquid phase sintered insert metal have shown no growth, while Ni and Fe particles grow rapidly. In this TLP bonding using the MBF-60 and distributed Fe, Ni particles as insert materials, the whole isothermal solidification process was dominated by the growth rate of the solid particles distributed in the interlayer.

• 마이크로전자및패키징학회지
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• 제25권4호
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• pp.9-15
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• 2018

This paper shows the principles and characteristics of the transient liquid phase (TLP) bonding technology for power modules packaging. The power module is semiconductor parts that change and manage power entering electronic devices, and demand is increasing due to the advent of the fourth industrial revolution. Higher operation temperatures and increasing current density are important for the performance of power modules. Conventional power modules using Si chip have reached the limit of theoretical performance development. In addition, their efficiency is reduced at high temperature because of the low properties of Si. Therefore, Si is changed to silicon carbide (SiC) and gallium nitride (GaN). Various methods of bonding have been studied, like Ag sintering and Sn-Au solder, to keep up with the development of chips, one of which is TLP bonding. TLP bonding has the advantages in price and junction temperature over other technologies. In this paper, TLP bonding using various materials and methods is introduced. In addition, new TLP technologies that are combined with other technologies such as metal powder mixing and ultrasonic technology are also reviewed.

• Journal of Welding and Joining
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• 제23권2호
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• pp.52-58
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• 2005

This study was carried out to investigate the effect of bonding temperature and heating rate on transient liquid phase diffusion bonding of Ni-base superalloy. The heating rate was varied by $0.1^{\circ}C$/sec, $1^{\circ}C$/sec, $10^{\circ}C$/sec to the bonding temperatures $1100^{\circ}C,\;1150^{\circ}C,\;1200^{\circ}C$ under vacuum. As bonding temperature increased, maximum dissolution width of base metal increased, but a dissolution finishing time decreased. The eutectic width of insert metal in the bonded interlayer decreased linearly in proportion to the square root of holding time during isothermal solidification stage. The bonding temperature was raised, isothermal solidification rate slightly increased. As the heating rate decreased and the bonding temperature increased, the completion time of dissolution after reaching bonding temperature decreased. When the heating rate was very slow, the solidification proceeded before reaching bonding temperature and the time required for the completion of isothermal solidification became reduced.