Solid-state reactions between Ni and Sn–Ag–Cu solders with different Cu concentrations

Luo, Wei‐Chen; Ho, Cheng–En; Tsai, Jang-Zern; Lin, Yen‐Ting; Kao, C. R.

doi:10.1016/j.msea.2005.02.008

Cited by 119 publications

(54 citation statements)

References 25 publications

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“…For example, a detailed study of the microstructures of the regions next to the Sn/Cu interface revealed numerous tubes and bundles of Cu 6 Sn 5 fibers inside the solder matrix, the formation of which has not been clarified. 13 In a few recent publications [14][15][16][17][18][19][20] the formation of intermetallic layers between Cu-bearing lead-free solders and a Ni substrate or between Ni-bearing lead-free solders and a Cu substrate have been explained by making use of the diagram proposed by Lin et al 21 On the other hand, Hsu et al 22 and Wang and Liu 23 used an earlier preliminary version of the Sn-Cu-Ni isothermal section 24,25 to explain the formation of (Cu,Ni) 6 Sn 5 in soldering reactions between Cu-alloyed Sn-Ag solders and a Ni substrate as well as in the Ni/Sn-3.5Ag/Cu sandwich structure. However, the authors did not consider either the supersaturation of the solder with dissolved Cu and Ni atoms or the existence of the metastable solubility limit.…”

Section: Introductionmentioning

confidence: 99%

“…The published results show slightly different values related to the minimum amount of Cu in Sn-based solders which is required to change the primary intermetallic compound from (Ni,-Cu) 3 Sn 4 to (Cu,Ni) 6 Sn 5 between the solder and Ni metallization. [14][15][16][17][18][19][20][21][22][23] For example, Alam et al presented that after 20 min annealing of Sn-3.5Ag-0.5Cu (wt.%) on Ni/Au metallization at 240°C the Cu content of the liquid has decreased to 0.2 wt.%, and that was the reason why (Ni,Cu) 3 Sn 4 started to form between Ni and (Cu,Ni) 6 Sn 5 . 26 Hsu et al annealed the binary liquid SnCu solders on Ni/Ti thin-film metallization at 250°C for different periods of time up to 20 min.…”

Section: Introductionmentioning

confidence: 99%

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Formation of Intermetallic Compounds Between Liquid Sn and Various CuNi x Metallizations

Vuorinen

Laurila

et al. 2008

Journal of Elec Materi

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Interfacial reactions between liquid Sn and various Cu-Ni alloy metallizations as well as the subsequent phase transformations during the cooling were investigated with an emphasis on the microstructures of the reaction zones. It was found that the extent of the microstructurally complex reaction layer (during reflow at 240°C) does not depend linearly on the Ni content of the alloy metallization. On the contrary, when Cu is alloyed with Ni, the rate of thickness change of the total reaction layer first increases and reaches a maximum at a composition of about 10 at.% Ni. The reaction layer is composed of a relatively uniform continuous (Cu,Ni) 6 Sn 5 reaction layer (a uniphase layer) next to the NiCu metallizations and is followed by the two-phase solidification structures between the single-phase layer and Sn matrix. The thickness of the two-phase layer, where the intermetallic tubes and fibers have grown from the continuous interfacial (Cu,Ni) 6 Sn 5 layer, varies with the Ni-to-Cu ratio of the alloy metallization. In order to explain the formation mechanism of the reaction layers and their observed kinetics, the phase equilibria in the Sn-rich side of the SnCuNi system at 240°C were evaluated thermodynamically utilizing the available data, and the results of the Sn/Cu x Ni 1-x diffusion couple experiments. With the help of the assessed data, one can also evaluate the minimum Cu content of Sn-(Ag)-Cu solder, at which (Ni,Cu) 3 Sn 4 transforms into (Cu,Ni) 6 Sn 5 , as a function of temperature and the composition of the liquid solders.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Formation of Intermetallic Compounds Between Liquid Sn and Various CuNi x Metallizations

Vuorinen

Laurila

et al. 2008

Journal of Elec Materi

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“…8 This strong sensitivity is similar to the Cu concentration sensitivity in the reaction between SnAgCu solders and Ni substrates. [10][11][12][13][14] However, note that the above Zn concentration sensitivity was established in bulk reactions where the supply of Zn was large. In other words, the Zn concentration remained almost constant.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Experimental Verification of the Volume Effect in the Reaction Between Zn-Doped Solders and Cu

Yang

Wang

Chang

et al. 2008

Journal of Elec Materi

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The volume effect in the reaction between Zn-doped solders and Cu is reported and explained in this article. Zn-doped solders with two different volumes, bulk solder baths (6 g) and small solder balls (10 mg), were reacted with Cu substrates. It was found that the reaction at the interface depended not only on the Zn concentration but also on the volume of the solder. For the bulk solder reaction the Zn concentration stayed nearly constant, whereas in the small solder joint case the Zn concentration changed substantially with the reaction time. This was because the Zn concentration during reaction was different for different solder volumes when the volume effect became important. For bulk solder baths, when the Zn content was 0.5 wt.%, the reaction product was a Cu 6 Sn 5 -based compound. As the Zn content increased to 2 wt.%, the reaction product switched to a Cu 5 Zn 8 -based compound. When the Zn content was 1.0 wt.%, Cu 6 Sn 5 and CuZn formed simultaneously. When the solder volume became smaller, the Zn concentration was no longer constant, and the phase equilibrium at the interface changed with time. It was shown that the shifting of the equilibrium at the interface caused the massive spalling of CuZn.

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“…Among such Sn-base alloys, the Sn-Ag alloy is one of the most favorable candidates of Pb-free solders. [9][10][11][12][13][14][15][16][17][18][19][20] On the other hand, owing to high electrical conductivity, Cu-base alloys are widely utilized as conductor materials in the electronics industry. When the Cubase conductor is interconnected with a Sn-base solder, Cu 6 Sn 5 and Cu 3 Sn are formed at the interconnection between the conductor and the solder during soldering and then gradually grow during energization heating at solid-state temperatures.…”

Section: Introductionmentioning

confidence: 99%

Experimental Observation on Solid-State Reactive Diffusion between Sn–Ag Alloys and Ni

2017

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The kinetics of the solid-state reactive diffusion between Sn-Ag alloys and pure Ni was experimentally observed to examine effects of addition of Ag into Sn on the growth behavior of compound at the interconnection between the Sn-base solder and the multilayer Au/Ni/Cu conductor during energization heating. In this experiment, sandwich (Sn-Ag)/Ni/(Sn-Ag) diffusion couples with Ag concentrations of y = 0.011-0.033 were prepared by a diffusion bonding technique, and then isothermally annealed at temperatures of T = 453-473 K for various periods up to 3169 h, where y is the mol fraction of Ag. After annealing, an intermetallic layer consisting of Ni 3 Sn 4 was recognized between the Sn-Ag and Ni specimens in the diffusion couple. Here, the concentration of Ag in Ni 3 Sn 4 is negligible. The mean thickness of the intermetallic layer is proportional to a power function of the annealing time, and the exponent of the power function takes values of 0.33-0.43 at T = 453 K and those of 0.54-0.62 at T = 473 K. Thus, the growth of the intermetallic layer is controlled by boundary and volume diffusion at T = 453 K. In contrast, at T = 473 K, interface reaction and interdiffusion contribute to the rate-controlling process of the intermetallic growth. The addition of Ag into Sn accelerates the intermetallic growth within the experimental annealing times.

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Solid-state reactions between Ni and Sn–Ag–Cu solders with different Cu concentrations

Cited by 119 publications

References 25 publications

Formation of Intermetallic Compounds Between Liquid Sn and Various CuNi x Metallizations

Formation of Intermetallic Compounds Between Liquid Sn and Various CuNi x Metallizations

Analysis and Experimental Verification of the Volume Effect in the Reaction Between Zn-Doped Solders and Cu

Experimental Observation on Solid-State Reactive Diffusion between Sn–Ag Alloys and Ni

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