• Transactions of Materials Processing
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• v.31 no.4
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• pp.179-185
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• 2022

The influence of post-roll bonding heat treatment conditions such as temperature and time on the variation in the diffusion layer, generated at the bonding interface and the subsequent mechanical properties of the roll-bonded Ti grade 1/Al1050/Ti grade 1 sheets, was systematically investigated. The intermetallic compound (IMC) phase generated by post heat treatment conditions adopted in this study was obviously indexed as monolithic TiAl₃. Whereas the thickness of IMC layer generated by annealing at 500 ℃ was approximately 100 nm scale, it drastically increased above 1.5 ㎛ when annealed at 600 ℃. Uniaxial tensile and peel tests were then performed to compare mechanical properties. As a result, the bonding strength drastically increased above 7.9 N/mm by annealing at 600 ℃, which implies that proper annealing condition was a prerequisite, to improving interface bonding strength as well as global elongation properties for Ti/Al/Ti 3-ply sheet.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4062-4071
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• 2022

Long-term aluminum (Al) corrosion tests were designed to investigate the condition that would generate severe Al corrosion and precipitation. Buffer agents of sodium tetraborate (NaTB), trisodium phosphate (TSP) and sodium hydroxide (NaOH) were adopted. The insulation materials, fiberglass and calcium silicate (Ca-sil), were examined to explore their effects on Al corrosion. The results show that significant precipitates were formed in both NaTB/TSP-buffered solutions at high pH. The precipitates formed in NaTB solution raise more concerns on chemical effects in GSI-191. A passivation layer formed on the surfaces of coupon in solution with the presence of insulations could effectively mitigate Al corrosion. The Fe-enriched intermetallic particles (IPs) embedded in coupon appeared to serve as seeds to readily induce precipitation via providing extra area for heterogeneous Al hydroxide precipitation. X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses indicate that the precipitates are mainly boehmite (γ-AlOOH) and no direct evidence confirms the presence of sodium aluminum silicate or calcium phosphate.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.84-87
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• 2003

Since Pb-free solder alloys have been used extensively in microelectronic packaging industry, the interaction between UBM (Under Bump Metallurgy) and solder is a critical issue because IMC (Intermetallic Compound) at the interface is critical for the adhesion of mechanical and the electrical contact for flip chip bonding. IMC growth must be fast during the reflow process to form stable IMC. Too fast IMC growth, however, is undesirable because it causes the dewetting of UBM and the unstable mechanical stability of thick IMC. UP to now. Ni and Cu are the most popular UBMs because electroplating is lower cost process than thin film deposition in vacuum for Al/Ni(V)/Cu or phased Cr-Cu. The consumption rate and the growth rate of IMC on Ni are lower than those of Cu. In contrast, the wetting of solder bumps on Cu is better than Ni. In addition, the residual stress of Cu is lower than that of Ni. Therefore, the alloy of Cu and Ni could be used as optimum UBM with both advantages of Ni and Cu. In this paper, the interfacial reactions of Sn-3.5Ag-0.7Cu solder on Ni-xCu alloy UBMs were investigated. The UBMs of Ni-Cu alloy were made on Si wafer. Thin Cr film and Cu film were used as adhesion layer and electroplating seed layer, respectively. And then, the solderable layer, Ni-Cu alloy, was deposited on the seed layer by electroplating. The UBM consumption rate and intermetallic growth on Ni-Cu alloy were studied as a function of time and Cu contents. And the IMCs between solder and UBM were analyzed with SEM, EDS, and TEM.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.1-7
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• 2010

Interfacial reaction characteristics of a Bi-10Cu-20Sb-0.3Ni Pb-free alloy on Cu pad was investigated by reflow soldering at $430^{\circ}C$. The thickness of interfacial reaction layers with respect to the soldering time was also measured. After the reflow soldering, it was observed that a $(Cu,Ni)_2Sb$, a $Cu_4Sb$ intermetallic layer, and a haze layer, which is consisted of Bi and $Cu_4Sb$ phases, were successively formed at the Bi-10Cu-20Sb-0.3Ni/Cu interface. The total thickness of the reaction layers was found to be linearly increased with increasing of the reflow soldering time up to 120 s. As the added Ni element did not participate in the formation of the thickest $Cu_4Sb$ interfacial layer, suppression of the interfacial growth was not observed.

• Journal of the Korean institute of surface engineering
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• v.29 no.4
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• pp.278-285
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• 1996

The structure of coating layer formed by hot dip Al-Cu alloy coating on Monel 1400 metal was studied. The coating layer consists of alloyed layer adjacent to the Monel 400 substrate and Al-Cu alloy. It was found that the hardness of coating increased with dipping time and heat treatment associated with the diffusion and the formation of intermetallic compound at the interface. However the thickness of coating layer was decreased at high dipping temperature due to tile higher viscosity of liquid coating alloy. Diffusion heat treatment at $600^{\circ}C$ after coating resulted in the disappearence of adhered Al(Cu) and $CuAl_2$ phases, and then they transformed into the new phases of CuAl and Al7Cu4Ni at coating layer.

• Journal of Welding and Joining
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• v.15 no.3
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• pp.128-135
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• 1997

Reaction diffusion and formation of $Ni_3Al$phase with $L1_2$ structure have been studied in temperature range of 1432K to 1573K using the diffusion couple of (Ni-40, 5at%Al)/(Ni-14, 1at%Al) and (Ni-49, 2at%Al)/ (Nickel). The layer growth of Ni$_{3}$Al pyhase in the annealed diffusion couple was measured by optical microscope and electron probe microanalyzer (EPMA). The layer growth of $Ni_3Al$phase in diffusion zone obeyed the parabolic law without any indication of grain boundary effects. The layer growth of $Ni_3Al$phase in temperature range of 1423K to 1573K was mainly controlled by the volume diffusion mechanism. The rate of layer growth of $Ni_3Al$phase was found to be colsely related to the composition of intermetallic compound NiAl phase. The activation energy for layer growth of $Ni_3Al$phase was calculated to be 127kJ/mol.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.332-336
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• 2001

In this study, the reaction at UBM(Under Bump Metallurgy) and solder interface was investigated. The UBM employed in conventional optical packages, Au/Pt/Ti layer, were found to dissolve into molten Au-Sn eutectic solder during reflow soldering. Therefore, the reaction with different diffusion barrier layer such as Fe, Co, Ni were investigated to replace the conventional Pt layer. The reaction behavior was investigated by reflowing the solder on the pad of the metals defined by Cr layer for 1, 2, 3, 4, and 5 minutes at $330^{\circ}C$. Among the metals, Co was found to be most suitable for the diffusion barrier layer as the wettability with the solder was reasonable and the reaction rate of intermetallic formation at the interface is relatively slow.

• Journal of the Korean institute of surface engineering
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• v.35 no.4
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• pp.193-198
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• 2002

Alloys of XD45 (Ti45A12Nb2Mn-0.8vol%TiB$_2$) and XD47 (Ti47A12Nb2Mn-0.8vol%TiB$_2$) were oxidized between 800 and $1000^{\circ}C$ in air, and their oxidation characteristics were studied. The oxide scales consisted primarily of an outer $TiO_2$ layer, an intermediate $Al_2$$O_3$-rich layer, and an inner mixed layer of ($TiO_2$+$Al_2$$O_3$). Nb tended to present at the lower part of the oxide scale, whereas Mn at the upper part of the oxide scale. The Pt marker tests indicated that the outer oxide layer grew primarily by the outward diffusion of Ti and Mn, and the inner mixed layer by the inward transport of oxygen.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.332-336
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• 2001

In this study, the reaction at UBM(Under Bump Metallurgy) and solder interface was investigated. The UBM employed in conventional optical packages, Au/Pt/Ti layer, were found to dissolve into molten Au-Sn eutectic solder during reflow soldering. Therefore, the reaction with different diffusion barrier layer such as Fe, Co, Ni were investigated to replace the conventional R layer. The reaction behavior was investigated by reflowing the solder on the pad of the metals defined by Cr layer for 1, 2, 3, 4, and 5 minutes at 330$^{\circ}C$. Among the metals, Co was found to be most suitable for the diffusion barrier layer as the wettability with the solder was reasonable and the reaction rate of intermetallic formation at the interface is relatively slow.

• Journal of the Korean institute of surface engineering
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• v.16 no.4
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• pp.153-159
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• 1983

The growth rate equation of Fe-Zn alloy layer was represented by x = Kt, and hence the growth of alloy layer was considered to be controlled by diffusion process. The constituent of alloy layer formed on the steel surface was identified to be intermetallic compound of Fe3Zn10 and FeZn10. The ultimate tensile strength and elongation of galvanized steel showed a nearly constant value at the thickness below about 30$\mu\textrm{m}$, and both properties decreased with increasing thickness above about 30$\mu\textrm{m}$. In the case of galvanied steel with a great thickness of alloy layer, crack was formed below yield point of base metal, which is considered to be attributed to the alloy layer failure.