The growth of Cu-Sn intermetallics at a pretinned copper-solder interface

Sunwoo, A.J.; Morris, J. W.; Lucey, G. K.

doi:10.1007/bf02665064

Cited by 169 publications

(88 citation statements)

References 20 publications

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“…However, CuSn intermetallic compounds are produced at the interface between the solder and conductor alloys during soldering and then soakingly grow owing to heating under usual energization conditions. [1][2][3][4][5][6][7][8][9] The Cu-Sn compounds are very brittle and possess high electrical resistivities. Hence, the growth of such compounds gradually deteriorates the electrical and mechanical properties of the interconnection.…”

Section: Introductionmentioning

confidence: 99%

Reactive Diffusion between Ag and Sn at Solid State Temperatures

et al. 2005

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The reactive diffusion at solid-state temperatures was experimentally studied for the binary Ag-Sn system. Sn/Ag/Sn diffusion couples were prepared by a diffusion bonding technique and then annealed at temperatures between T ¼ 433 and 473 K for various periods in an oil bath with silicone oil. After annealing, layers of the " (Ag 3 Sn) and compounds were observed to form at the Sn/Ag interface. Furthermore, a thin layer alloyed with Sn was produced into the Ag specimen from the /Ag interface owing to diffusion induced recrystallization (DIR). The thickness is about one order of magnitude greater for the " layer than for the and DIR layers. The total thickness l of the " and layers is described as a function of the annealing time t by the equation l ¼ kðt=t 0 Þ n . Here, t 0 is unit time, 1 s. The exponent n is 0.40, 0.38 and 0.36 at T ¼ 433, 453 and 473 K, respectively. If the reactive diffusion is controlled by the volume diffusion, n is equal to 0.5. However, n is actually smaller than 0.5 at all the annealing temperatures. This indicates that the grain boundary diffusion contributes to the reactive diffusion and the grain growth occurs at certain rates. As the annealing temperature decreases, the contribution of the grain boundary diffusion should be more remarkable, but the grain growth will become sluggish. This is the reason why the value of n increases with decreasing annealing temperature.

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Section: Introductionmentioning

confidence: 99%

Reactive Diffusion between Ag and Sn at Solid State Temperatures

et al. 2005

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“…(Tl-phase andTl'-phase) andCu3Sn (E-phase). The crystallography ofthese phases has bccnrecently reviewed by Sunwoo [7]. "Thevl-phase (Cu6Sn5)hasanordered, hours in a saturated steam zone above vigorously boiling-distilled water held to within 6"C of the local boiling point.…”

Section: 23 Tho Sessile Drop Methodsmentioning

confidence: 99%

“…[ 11] As can be seen from the varied test results and conclusions drawn from the investigations listed above, there is not a standard accelerated aging method which corresponds directly to natural aging. [7,13,14,15]. Curves showing the growth rate of the duplex intermetallic layer were determined experimentally for storage times greater than 4 years [ 12].…”

Section: 23 Tho Sessile Drop Methodsmentioning

confidence: 99%

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Aging effects on the microstructure, surface characteristics and wettability of Cu pretinned with Sn-Pb solders

Linch

1993

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This study investigates the effects of aging in air and argon at 170°C on Cu coupons which were pretinned with 75Sn-25Pb, 8Sn-92Pb, and 5Sn-95Pb solders. Coatings were applied using electroplating or hot dipping techniques.The coating thickness was controlled between 3 to 30ktm and the specimens were aged for 0 hours, 2 hours, 24 hours and 2 weeks. Wetting balance tests were used to evaluate the wettability of the test specimens. Microstructural development was evaluated using X-ray diffraction, energy d_spersive X-ray and Auger spectroscopy, as well as optical and scanning electron microscopy.The wetting behavior of the test specimens is interpreted with respect to observed microstructural changes and as a function of aging time, solder composition, and processing conditions. i Graph showing the net (excluding plateau) time to 90% of the maximum wetting force as a function of coating thickness and aging time for the Sn-rich (75Sn-25Pb), electroplated samples aged in air. showing cross-section of a Pb-rich (5Sn-95Pb), hot-dipped (360°C) specimen which was aged in argon at 170°C for 2 weeks. LIST of TABLESix

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“…Because Zn has a higher heat of fusion of 115.79 J/g and the heat of fusion for melting the Znrich phase in the Sn-9Zn solder alloy is not necessary to consume for the one of Sn-9Zn-0.5Ag, which make the Sn9Zn-0.5Ag solder alloy have a heat of fusion close to pure Sn. 28,29) it was found that the IMCs formed at the Cu-Sn diffusion couple and Sn-37Pb/Cu interface are -Cu 6 Sn 5 and "-Cu 3 Sn. Suganuma et al 30) have reported that the first IMC layer at the Sn-9Zn/Cu interface is Cu reported by Yu et al 31) In the present study, the bi-structural Cu 6 Sn 5 and bcc Cu 5 Zn 8 layers coexist at the Sn-9Zn-0.5Ag/ Cu interface, which are different from the result obtained in the Sn-9Zn solder system.…”

Section: Thermal Properties Of the Solder Alloysmentioning

confidence: 99%

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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The growth of Cu-Sn intermetallics at a pretinned copper-solder interface

Cited by 169 publications

References 20 publications

Reactive Diffusion between Ag and Sn at Solid State Temperatures

Reactive Diffusion between Ag and Sn at Solid State Temperatures

Aging effects on the microstructure, surface characteristics and wettability of Cu pretinned with Sn-Pb solders

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

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