Volume effect on the soldering reaction between SnAgCu solders and Ni

Ho, Cheng–En; Lin, Yu-Mu; Yang, Shun‐Chung; Kao, C. R.

doi:10.1109/isapm.2005.1432042

Cited by 22 publications

(15 citation statements)

References 15 publications

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“…Therefore it can be concluded that the effect of temperature on the critical Cu composition is significant and thus it is now possible to explain the (Cu,Ni) 6 Sn 5 precipitates on the top of the (Ni, Cu) 3 Sn 4 observed in Refs. 14,15,18,19 when the Cu content of the Sn-Ag-Cu solder was 0.4 wt.%. As can be seen from Fig.…”

Section: Critical Cu Content In Reactions Between Sn-rich Solders Andmentioning

confidence: 99%

“…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: Critical Cu Content In Reactions Between Sn-rich Solders Andmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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“…The quantity of IMC formed is a function of soldering time and temperature and subsequent aging conditions. The degree to which a particular soldered interface is susceptible to brittle failure depends on the composition of the IMC e. g. Cu3Sn is the more brittle of the two binary CuSn IMCs, the thickness of the IMC and the presence of defects either as (Kirkendall) voids, incipient cracks or residual stress between IMC layers e. g. (Ni,Cu)6Sn5 over (Ni,Cu)3Sn4 [2,3]. Improved drop shock performance can be improved therefore by controlling the initial IMC formation, its subsequent development through device life and the IMC defects.…”

Section: Introductionmentioning

confidence: 99%

Drop Shock Reliability of Lead-Free Alloys - Effect of Micro-Additives

Pandher¹,

Lewis²,

Vangaveti³

et al. 2007

2007 Proceedings 57th Electronic Components and Technology Conference

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The drop shock reliability of solder joints has become a major issue for the electronic industry partly because of the ever increasing popularity of portable electronics and partly due the transition to lead free solders. Most of the commonly recommended lead-free are high Sn alloys which have relatively higher strength and modulus. This plays a critical role in the reliability of Pb-free solder joints. Further, even though metallugically it is the Sn in the solder alloys that principally participates in the solder joint formation, details of the IMC layers formed with SnPb and Pb-free alloys are different. The markedly different process conditions for SnPb and Pb-free alloys also bear on solder joint quality.Brittle failure of solder joints in drop shock occurs at or in the interfacial IMC layer(s). This is due to the inherent brittle nature of the IMC, defects within or at IMC interfaces or transfer of stress to the interfaces as a result of the low ductility of the bulk solder.In developing improved performance alloys, Cookson Electronics has addressed both issues -improved ductility and modification and control of the intermetallic layer. A broad range of base alloy compositions together with selected micro-alloying additions to SnAgCu alloys have been evaluated with the objective of controlling bulk alloy mechanical properties and the diffusion processes operating in the formation and growth of the intermetallic interfacial layer(s).In the present article a detailed study of a range of microalloy additives is presented. The alloy additives generally act as diffusion modifiers slowing interdiffusion between substrates and solder thereby reducing IMC thickness or the propensity for void formation. Alternatively additions can be made that act as diffusion compensatorsD. It should be noted that the level of the micro-additions does not measurably modify the bulk mechanical properties of the base alloys. Our results show that dramatic improvements in the solder joint reliability, as demonstrated by high-speed ball pull and drop shock tests, can be achieved.

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“…When the Cu concentration changes, the IMC growth mechanism at the interface may also change. This makes the situation much more complicated [19]. As the size of the joints shrinks, the variation in Cu concentration becomes more critical.…”

Section: Growth Mechanism Of the Imc Formationmentioning

confidence: 99%

Size effect on IMC growth in micro-scale Sn-3.0Ag-0.5Cu-0.1TiO2 solder joints in reflow process

et al. 2016

Journal of Alloys and Compounds

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Volume effect on the soldering reaction between SnAgCu solders and Ni

Cited by 22 publications

References 15 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

Drop Shock Reliability of Lead-Free Alloys - Effect of Micro-Additives

Size effect on IMC growth in micro-scale Sn-3.0Ag-0.5Cu-0.1TiO2 solder joints in reflow process

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