Rapid penetration of liquid Bi along Cu grain boundaries

Joseph, B.; Barbier, F.; Dagoury, G.; Aucouturier, Marc

doi:10.1016/s1359-6462(98)00230-9

Cited by 53 publications

(21 citation statements)

References 5 publications

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“…In our case, Cu/Bi system after heat-treatment at 500°C for 137 hours, we did not observe such a phenomenon. This is in apparent contradiction with earlier results obtained using XPS for the same Cu/Bi system where several monolayers of bismuth were thought to exist in a copper grain boundary 6 (heat treatment: 8 h at 600°C). Yet, Joseph 33 made complementary AES analyses on a 2.0 ð 3.5 mm 2 bicrystalline fracture surface (heat treatment: 2 h at 600°C) and found an homogeneous bismuth coverage of about 93% of the monolayer, which is in reasonable agreement with our present results.…”

Section: Implications On Lme Phenomenoncontrasting

confidence: 99%

Quantitative AES, XPS and RBS determination of intergranular bismuth coverage in copper bicrystals at 500 °C

Laporte

Berger²,

Wolski

2005

Surface & Interface Analysis

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We report on a comparative measurement of intergranular bismuth coverage on a copper substrate using Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy (RBS). Bicrystalline copper samples were put in presence of bismuth vapour at 500°C (consequently embrittled by the grain-boundary penetration of Bi atoms), water-quenched and subsequently fractured at room temperature. Each fracture surface was analysed by AES, XPS and RBS with the help of quantitative procedures developed for each of the three techniques. All possible sources of discrepancy were carefully examined. The combined quantitative approaches have led to excellent agreement. Such a good agreement constitutes a necessary condition to begin a critical discussion on the mechanisms potentially involved in the liquid metal embrittlement (LME) phenomenon.

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Section: Implications On Lme Phenomenoncontrasting

confidence: 99%

Quantitative AES, XPS and RBS determination of intergranular bismuth coverage in copper bicrystals at 500 °C

Laporte

Berger²,

Wolski

2005

Surface & Interface Analysis

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“…20 According to the classic theory, the grain-boundary grooving depth is time dependent, which is controlled by the reflow temperature, boundary curvatures, grain-boundary diffusion, dissolution of solids into the liquid (nature of solid), stress in tip region, convection, etc. [19][20][21][22] The penetrated Sn was encapsulated inside and formed the so-called white patches after the reflow solidification process. Because the metallic bonds among the IMC atoms have to be broken first before the IMC can dissolve into the molten solder, the bonding strength is believed to be a controlling factor governing the dissolution rate.…”

Section: Effects Of Ni From the Substrate On The Fast Spalling Of Thementioning

confidence: 99%

Effects of substrate metallization of solder/under-bump metallization interfacial reactions in flip-chip packages during multiple reflow cycles

Zhang

Chum

Shao³

2003

Journal of Elec Materi

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The effects of various elements of substrate metallization, namely, Au, Ni, and P, on the solder/under-bump metallization (UBM), (Al/Ni(V)/Cu) interfacial reactions in flip-chip packages during multiple reflow processes were systematically investigated. It was found that Au and P had negligible effects on the liquid-solid interfacial reactions. However, Ni in the substrate metallization greatly accelerated the interfacial reactions at chip side and degraded the thermal stability of the UBM through formation of a (Cu,Ni) 6 Sn 5 ternary compound at the solder/UBM interface. This phenomenon can be explained in terms of enhanced grain-boundary grooving on (Cu,Ni) 6 Sn 5 in the molten solder during the reflow process. This could eventually cause the rapid spalling of an intermetallic compound (IMC) from the solder/UBM interface and early failure of the packages. Our results showed that formation of multicomponent intermetallics, such as (Cu,Ni) 6 Sn 5 or (Ni,Cu) 3 Sn 4 , at the solder/UBM interface is detrimental to the solder-joint reliability.

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“…Joseph et al 32 studied the dissolution and grooving along grain boundaries of copper immersed in pure bismuth and in bismuth nearly saturated with copper (at 873 K, the solubility of copper is $11 wt.%). They observed the dissolution of Cu in both liquids; however grooving along grain boundaries was observed in the case of bismuth saturated with copper.…”

Section: Wetting and Interfacial Chemistrymentioning

confidence: 99%

Wetting of Cu Pads by Bi-2.6Ag-xCu Alloys and Phase Equilibria in the Ag-Bi-Cu System

Fima

Garzeł

Sypień

2014

Journal of Elec Materi

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The phase equilibrium in the Ag-Bi-Cu system was experimentally determined at 573 K, 773 K, and 973 K by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) on annealed alloys and liquid/solid couples. The experimental results indicate that the mutual solubility of the components is limited. Based on the present results and literature data, phase equilibria in the Ag-Bi-Cu system were thermodynamically assessed. Wetting of Bi-2.6Ag-xCu alloys on Cu substrates was studied with the sessile drop method in the presence of flux at 573 K and 623 K. It was found that the wetting to non-wetting transition corresponds to the solubility limit of Cu in liquid. Selected solidified solder-substrate couples were cross-sectioned and their interfacial microstructure examined with SEM-EDS. There are no reaction products at the interface, but the copper surface becomes rough because of dissolution by liquid solder.

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Rapid penetration of liquid Bi along Cu grain boundaries

Cited by 53 publications

References 5 publications

Quantitative AES, XPS and RBS determination of intergranular bismuth coverage in copper bicrystals at 500 °C

Quantitative AES, XPS and RBS determination of intergranular bismuth coverage in copper bicrystals at 500 °C

Effects of substrate metallization of solder/under-bump metallization interfacial reactions in flip-chip packages during multiple reflow cycles

Wetting of Cu Pads by Bi-2.6Ag-xCu Alloys and Phase Equilibria in the Ag-Bi-Cu System

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