Comparative study of the dissolution kinetics of electrolytic Ni and electroless Ni–P by the molten Sn3.5Ag0.5Cu solder alloy

Islam, M. N.; Chan, Yiu Che; Sharif, Ahmed; Alam, Md. Mahbubul

doi:10.1016/s0026-2714(03)00190-2

Cited by 57 publications

(36 citation statements)

References 7 publications

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“…Although the thickness reduction of the Ni(-P) layers was smaller than the increase of the IMC thickness during aging, the average consumption rate of the electroless Ni-P layer was much lower than that of the electrolytic Ni layer. A similar result has been reported by Chan and co-authors, 25 providing the dissolution rates of both electroless Ni-P and electrolytic Ni layers as functions of SAC reflow time. According to their result, for up to 50 min of reflow, 150°C for 125 h (a, c) and 500 h (b, d).…”

Section: Growth Of Imcs After Reflow Soldering and Agingsupporting

confidence: 89%

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Inhomogeneous Consumption of the Electroless Ni-P Layer at the Solder Joint Formed with Sn-3.5Ag-0.7Cu

2009

Journal of Elec Materi

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This report investigates the phenomenon of interfacial serration at the joint between Sn-3.5Ag-0.7Cu solder (SAC) and electroless Ni-P underbump metallization (UBM) during aging. For comparison, the interface between SAC and electrolytic Ni UBM was also examined under similar aging conditions. The joint in the electrolytic Ni/SAC sample showed a smooth, flat interface between the Ni and intermetallic compounds, even after a long aging time. In contrast, electroless Ni-P/SAC exhibited an irregular interface, the irregularity of which became more severe with increased aging time. This observed roughness was initiated by large breaks across the P-rich layer. The breaks were filled with the overlying Ni-Sn-P phase material, which provided an easier interdiffusion path for Ni and Sn in the opposite direction. As a result, the local consumption of the Ni(-P) layer was accelerated, and the interface was serrated. The local maximum consumption rate of the Ni-P layer, as calculated from the minimum thickness of this layer in each sample with aging time, was similar to that of an electrolytic Ni layer.

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Section: Growth Of Imcs After Reflow Soldering and Agingsupporting

confidence: 89%

“…14,15 These additional crystalline P-rich layers with lower Ni contents retard the diffusion of Ni atoms toward the IMCs. 25 In contrast, the interface of the electrolytically pure Ni/IMCs permits Ni atoms to directly diffuse into the IMCs. This phenomenon is also revealed in Fig.…”

Section: Growth Of Imcs After Reflow Soldering and Agingmentioning

confidence: 99%

Inhomogeneous Consumption of the Electroless Ni-P Layer at the Solder Joint Formed with Sn-3.5Ag-0.7Cu

2009

Journal of Elec Materi

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“…20 As previously mentioned, the reactive diffusion between the Sn-base solder and the electroless Ni-P has been experimentally studied by many investigators. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] According to these studies, the enrichment of P in the Ni-P occurs owing to growth of Ni 3 Sn 4 and causes formation of Ni 3 P in the Ni-P adjacent to Ni 3 Sn 4 . In the case of the experiment by Li et al, 37) diffusion couples composed of electroless Ni-P Fig.…”

Section: Growth Behavior Of Ni 3 Snmentioning

confidence: 99%

“…[18][19][20] The Ni layer electrolessly deposited onto the Cu-base alloy usually contains 5-20 at% of P. The reactive diffusion between the electroless Ni-P layer and the Sn-base solder has been experimentally studied by many researchers. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] However, a soldering technique has been used in most of these studies. In this technique, a diffusion couple is prepared from a molten Sn-base solder and a (Ni-P)/Cu conductor material at soldering temperatures, and then isothermally annealed at solid-state temperatures.…”

Section: Introductionmentioning

confidence: 99%

Solid-State Reactive Diffusion between Sn and Electroless Ni–P at 473 K

Yamakami

Kajihara

2009

Mater. Trans.

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Nickel-phosphorus alloys are electrolessly deposited onto Cu-base conductors to suppress formation of Cu-Sn compounds during soldering using Sn-base solders. However, a Ni-Sn compound is produced during soldering, and continuously grows during energization heating at solid-state temperatures. To examine influence of P on the growth behavior of the Ni-Sn compound during energization heating, the kinetics of the solid-state reactive diffusion between Sn and electroless Ni-P alloys was experimentally determined at 473 K in the present study. For the experiment, pure Cu sheets were electrolessly deposited with Ni-P alloys containing 4.6 at%, 18.5 at% and 20.4 at% of P, and then sandwiched between pure Sn plates. Such Sn/(Ni-P)/Cu/(Ni-P)/Sn diffusion couples were isothermally annealed at 473 K for various periods up to 1307 h. During annealing, a layer of Ni 3 Sn 4 is formed along the Sn/(Ni-P) interface in the diffusion couple. The annealing time dependence of the mean thickness of the Ni 3 Sn 4 layer is expressed by a parabolic relationship. The parabolic coefficient slightly increases with increasing P concentration in the Ni-P. Thus, P in the Ni-P lightly accelerates the growth of Ni 3 Sn 4 at the interconnection between the Ni-P and the Sn-base solder. Using the experimentally determined values of the parabolic coefficient, the interdiffusion coefficient in Ni 3 Sn 4 was analytically evaluated by a mathematical model. The acceleration effect of P on the growth of Ni 3 Sn 4 is quantitatively explained by the dependence of the interdiffusion coefficient on the P concentration in the Ni-P.

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“…The possible reasons for this spalling of medium-Cu containing TIMCs in the NiP/Sn-Ag-Cu system are as follows: (1) high-Cu containing TIMCs may be more dense than the medium-Cu containing TIMCs, thus the first diffusion of atoms and interfacial reactions increases the dissolution rate of the NiP layer and the thickness of TIMCs, resulting in the greater spalling of medium-Cu containing TIMCs from the interface. 20,21 (2) Slightly brighter (in the SEM image) low-Cu containing (about 8.5 at.%) TIMCs formed between the medium-Cu containing TIMCs and the P-rich Ni layer (Fig. 8b), due to a lower supply of Cu from the Sn-Ag-Cu solder suggesting that medium-Cu containing TIMCs may not be stable on low-Cu containing TIMCs during extended reflow; (3) spalling may be due to the larger volume change between the medium-Cu containing TIMCs and P-rich Ni layer in this case compared to the other solder joints; 2 (4) the changes of interfacial energies between the P-rich Ni layer and low-Cu containing TIMCs, between low-Cu containing TIMCs and medium-Cu containing TIMCs layer, and between the medium-Cu containing TIMCs and the molten solder will have an effect on the morphology and may influence the degree of spalling.…”

Section: Interfaces After Long-time Molten Reactionsmentioning

confidence: 99%

Interfacial reactions of Cu-containing lead-free solders with Au/NiP metallization

Islam

Chan

2005

Journal of Elec Materi

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Cu-containing solder alloys have been used to identify their interfacial reactions with electroless NiP. As-reflowed, AuSn 4 intermetallic compounds (IMCs) are formed in the Sn-Cu and Sn-Ag-Cu solders, but in the cases of Sn-Ag-Cu-In, In-Sn-Au IMCs are formed and are uniformly distributed in the solder. Different types of IMCs such as high-Cu (Ͼ30 at.%), medium-Cu (30-15 at.%), and low-Cu (Ͻ15 at.%) containing IMCs are formed at the interface. High-Cu and medium-Cu containing ternary intermetallic compounds (TIMCs) are found in the Sn-Cu and Sn-Ag-Cu solder joints, respectively. Medium-Cu containing quaternary intermetallic compounds (QIMCs) are found in the Sn-Ag-Cu-In joints. Initially, TIMCs and QIMCs have higher growth rates, resulting in the entrapment of some Pb-rich phase in the high-Cu containing TIMCs and some In-Sn-Au phase in the QIMCs. High-Cu containing TIMCs have a lower growth rate and consume less of the NiP layer. The spalling of medium-Cu containing TIMCs in the Sn-Ag-Cu solder increases both the growth rate of TIMCs and the consumption rate of the NiP layer. Low-Cu containing QIMCs in the Sn-Ag-CuIn solder are stable on P-rich Ni and reduce the dissolution rate of the NiP layer. Consumption of the NiP layer can be reduced by adding Cu or In, because of the changes of the interfacial IMCs phases, which are stable and adhere well to the P-rich Ni layer during reflow.

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Comparative study of the dissolution kinetics of electrolytic Ni and electroless Ni–P by the molten Sn3.5Ag0.5Cu solder alloy

Cited by 57 publications

References 7 publications

Inhomogeneous Consumption of the Electroless Ni-P Layer at the Solder Joint Formed with Sn-3.5Ag-0.7Cu

Inhomogeneous Consumption of the Electroless Ni-P Layer at the Solder Joint Formed with Sn-3.5Ag-0.7Cu

Solid-State Reactive Diffusion between Sn and Electroless Ni–P at 473 K

Interfacial reactions of Cu-containing lead-free solders with Au/NiP metallization

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Comparative study of the dissolution kinetics of electrolytic Ni and electroless Ni–P by the molten Sn3.5Ag0.5Cu solder alloy

Cited by 57 publications

References 7 publications

Inhomogeneous Consumption of the Electroless Ni-P Layer at the Solder Joint Formed with Sn-3.5Ag-0.7Cu

Inhomogeneous Consumption of the Electroless Ni-P Layer at the Solder Joint Formed with Sn-3.5Ag-0.7Cu

Solid-State Reactive Diffusion between Sn and Electroless Ni&ndash;P at 473 K

Interfacial reactions of Cu-containing lead-free solders with Au/NiP metallization

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Solid-State Reactive Diffusion between Sn and Electroless Ni–P at 473 K