Copper substrate dissolution in eutectic Sn-Ag solder and its effect on microstructure

Chada, Srinivas; Fournelle, R.A.; Laub, W.; Shangguan, Dongkai

doi:10.1007/s11664-000-0015-6

Cited by 106 publications

(77 citation statements)

References 4 publications

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“…The values for the SnAg and SnCu alloys are consistent with those reported previously for IMC layer growth for eutectic Sn-Ag solder. 11,12) (2) Initial stage of intermetallic growth on Cu substrate As shown above, some IMC thickness values, notably those for short and long holding times, deviate from the least square fitted average growth line. The deviations are indeed the greatest on a percentage basis at short and long times and they are the greatest for the lower temperatures.…”

Section: )mentioning

confidence: 99%

Metallurgy and Kinetics of Liquid–Solid Interfacial Reaction during Lead-Free Soldering

Liang¹,

Dariavach²,

Callahan³

et al. 2006

Mater. Trans.

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The wetting of a molten solder on metallic surfaces is a rather complex phenomenon. In addition to physical spreading due to surface tension reduction, there are interfacial metallurgical and flux chemical reactions with the metallic substrate surface. Substrate dissolution and intermetallic formation take place rapidly during soldering. Since lead-free soldering requires substantially higher soldering temperatures (around 250 C), the rates of intermetallic growth and substrate dissolution for lead-free solders are expected to be significantly greater than those for the current Sn-Pb eutectic solder. This study systematically investigates the metallurgy of the solid-liquid interface reactions and intermetallic growth kinetics for three lead-free solders: Sn-Ag eutectic (96.5%Sn-3.5%Ag), Sn-Cu eutectic (99.3%Sn-0.7%Cu) and Sn-AgCu eutectic (Sn-3.8Ag-0.7Cu, SAC 387) with three metallic substrates: Cu, Ni, and Alloy 42 (42%Ni-52%Fe) over temperatures ranging from 225 to 280 C for reaction time from 10 s to 16 h. Wetting behavior of these three alloys on PCBs with OSP, immersion Sn, and Ni/Au finishes, was also examined from 220 C up to 260 C. A thorough understanding of lead-free solder/substrate interfacial reactions should give guidance to the optimum lead-free soldering processes and to the optimum lead-free coating thicknesses for component and PCB terminal finishes, as well as for under-chip metallurgical coatings for flip-chip and BGA applications.

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Section: )mentioning

confidence: 99%

Metallurgy and Kinetics of Liquid–Solid Interfacial Reaction during Lead-Free Soldering

Liang¹,

Dariavach²,

Callahan³

et al. 2006

Mater. Trans.

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“…Primary Cu6Sn5 has been reported to grow with various morphologies such as needles [10][11][12], hollow rods [11,13], X-shapes [9,14,15], Y-shapes [8,9], H-and M-shapes [16,17] and as dendrites [6,18]. Since many of these studies have been based on arbitrary 2D cross sections, it is not clear how many of these morphologies are separate growth forms in 3D.…”

Section: Introductionmentioning

confidence: 99%

Cu6Sn5 crystal growth mechanisms during solidification of electronic interconnections

et al. 2017

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The growth mechanisms of primary Cu6Sn5 are studied in Sn-Cu alloys and solder joints by combining EBSD, FIB-tomography and synchrotron radiography. With increasing cooling rate and Cu content, Cu6Sn5 crystals developed from faceted hexagonal rods to grooved rods, in-plane branched faceted crystals and, finally, to nonfaceted dendrites. This range of growth morphologies has been rationalised into a kinetic microstructure map. Cu6Sn5 hexagonal rods grew along [0001] bounded by {101 ̅ 0} facets and Cu6Sn5 dendrites branched along <405> in the {101 ̅ 0} planes. The faceted to nonfaceted transition indicates a kinetic interface roughening transition and a gradual change in mechanism from lateral growth governed by anisotropic attachment kinetics to continuous growth governed by diffusion and curvature. Finally, it is shown that the full range of Cu6Sn5 morphologies that grew for different composition and cooling rate combinations in bulk alloys can be engineered to grow in solder joints made with a single composition (Sn-0.7wt%Cu/Cu) by altering the peak temperature and the cooling rate.

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“…30,31) It is caused by that Ag promotes the formation of the Cu 6 Sn 5 layer because Ag increases the solubility of Cu in Sn. 32) The Ag 3 Sn IMC forms at the solder alloy/Cu interface when the Ag content in solder alloy is above 0.1 mass% as reported by Huh et al 33) From the XRD pattern, the Ag 3 Sn is found at the Sn-9Zn-0.5Ag/Cu interface because the Ag content in the solder alloy is higher than 0.1 mass%.…”

Section: Thermal Properties Of the Solder Alloysmentioning

confidence: 70%

Thermal Characteristics and Intermetallic Compounds Formed at Sn-9Zn-0.5Ag/Cu Interface

Chang

Hon

Wang³

2004

Mater. Trans.

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The thermal characteristics of various Sn-based solder alloys and intermetallic compounds (IMCs) formed at the Sn-9Zn-0.5Ag/Cu interface have been investigated by using differential scanning calorimetry, X-ray diffractometry, scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy and electron diffraction. The melting ranges of the Sn-37Pb, Sn-9Zn and Sn-3.5Ag alloys are 179:5$191:0, 195:5$208:1 and 220:4$227:8 C, and the heats of fusion are 104.2, 163.9 and 151.0 J/g, respectively. When 0.5 mass% Ag is added to the Sn-9Zn alloy, the melting temperature of the solder alloy increases from 195.5 to 196.7 C, but the melting range and heat of fusion decrease from 12.6 to 11.3 C and 163.9 to 74.7 J/g, respectively. The IMCs formed at the Sn-9Zn-0.5Ag/Cu interface are determined as a scallop-shaped Cu 6 Sn 5 near the solder alloy, a flat Cu 5 Zn 8 close to the Cu substrate and Ag 3 Sn particles between the Cu substrate and Cu 5 Zn 8 layer. The Cu 6 Sn 5 is bi-structural, namely, hexagonal and monoclinic, which is caused by the Ag dissolution in the Cu 6 Sn 5 layer.

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Copper substrate dissolution in eutectic Sn-Ag solder and its effect on microstructure

Cited by 106 publications

References 4 publications

Metallurgy and Kinetics of Liquid–Solid Interfacial Reaction during Lead-Free Soldering

Metallurgy and Kinetics of Liquid–Solid Interfacial Reaction during Lead-Free Soldering

Cu6Sn5 crystal growth mechanisms during solidification of electronic interconnections

Thermal Characteristics and Intermetallic Compounds Formed at Sn-9Zn-0.5Ag/Cu Interface

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Copper substrate dissolution in eutectic Sn-Ag solder and its effect on microstructure

Cited by 106 publications

References 4 publications

Metallurgy and Kinetics of Liquid&ndash;Solid Interfacial Reaction during Lead-Free Soldering

Metallurgy and Kinetics of Liquid&ndash;Solid Interfacial Reaction during Lead-Free Soldering

Cu6Sn5 crystal growth mechanisms during solidification of electronic interconnections

Thermal Characteristics and Intermetallic Compounds Formed at Sn-9Zn-0.5Ag/Cu Interface

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Metallurgy and Kinetics of Liquid–Solid Interfacial Reaction during Lead-Free Soldering

Metallurgy and Kinetics of Liquid–Solid Interfacial Reaction during Lead-Free Soldering