Ageing, Solder Thickness and Solder Alloy Effects on Circuit Board Solderability

Hagge, J.K.; Davis, George J.

doi:10.1108/eb045997

Cited by 10 publications

(5 citation statements)

References 1 publication

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“…However, the number of defects per board ranged from 0 to 6, not substantially higher than the 0 -2 defects observed for the untreated boards. Consistent with this, an earlier study [Hagge and Davis 1985] found that circuit boards steam aged for 4 hours exhibited fewer soldering defects than typical production boards. A reasonable explanation for the good performance observed is that the very thick oxides produced by steam aging can crack during wave soldering and be removed as scale, allowing the underlying solder coating to melt.…”

Section: Oxides Produced By Steam Agingsupporting

confidence: 57%

“…Although many workers have relied heavily on subjective dip-and-look solderability tests and have not adequately controlled the oxygen content during steam aging, there is nonetheless general agreement on several important points. Solderability degradation occurs much more rapidly in the presence of water vapor, for both artificial [Edington and Lawrence 1988;Steen and Bengston 1987;Geist 1983] and natural aging [Stoneman and MacKay 1977], and is most severe for the steam aging procedure [Edington and Lawrence 1988;Hagge and Davis 1985]. Insufficient coating thickness has consistently been found to be the most important factor leading to solderability loss.…”

Section: Accelerated Aging Proceduresmentioning

confidence: 99%

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Oxidation of Solder Coatings

Tench

1993

The Mechanics of Solder Alloy Wetting and Spreading

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Section: Oxides Produced By Steam Agingsupporting

confidence: 57%

Section: Accelerated Aging Proceduresmentioning

confidence: 99%

Oxidation of Solder Coatings

Tench

1993

The Mechanics of Solder Alloy Wetting and Spreading

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“…[1][2][3][4][5] During the life time of the products, thermal excursion and shocks are encountered. Failures due to aging can occur in field use and are often the result of intermetallic compound (IMC) growth.…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution in the Sn-Cu-Ni and Pb-Sn solder joints with Cu and Pt-Ag metallized Al2O3 substrate

Young

Duh

Tsai³

2001

J. Electron. Mater.

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Special Issue PaperThe growth mechanism of intermetallics between solders and metallized substrates, after thermal aging, are investigated. The solders used in this study are unleaded Sn-Cu-Ni solder and eutectic Pb-Sn solder. The Pt-Ag/Al 2 O 3 , Cu block and the electroless Cu/Pt-Ag/Al 2 O 3 are employed as the metallized substrates. Microstructure evolution of the interfacial morphology, elemental, and phase distribution are probed with the aid of electron-probe microanalyzer (EPMA) and x-ray diffractometry. Two kinds of intermetallics, Cu 3 Sn and Cu 6 Sn 5 , are formed at the solder/Cu interface. However, for the solder/Pt-Ag system, only Ag 3 Sn is observed at the interface. The thickness of Cu 3 Sn, Cu 6 Sn 5 , and Ag 3 Sn compound layers for all solder/metallized substrate systems shows a t 0.5 dependence at 100, 125, 150 and 170∞C. According to the calculated activation energy and diffusion constant, the growth rate of Cu 3 Sn and Cu 6 Sn 5 intermetallics in the electroless Cu metallized substrate is relatively higher than that for Cu block one at the range of 100∞C to 170∞C. However, the growth rate of Cu 6 Sn 5 and Ag 3 Sn is reduced in the Sn-Cu-Ni solder with respect to the eutectic Pb-Sn solder. On the other hand, the Sn-Cu-Ni solder system exhibits a thicker Cu 3 Sn intermetallic layer than the eutectic Pb-Sn solder after various aging times at 100∞C. The thickness of Cu3Sn in the eutectic Pb-Sn solder is, however, thicker than that for Sn-Cu-Ni solder at 170∞C.

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“…Alternatively, signifi-cant reactivity occurs even below the melting temperature of the solder, as was shown by Walker and De-Haven (1984). These reactions between the solder and metallization form intermetallic phases, which are generally detrimental to solder wetting (Hagge and Davis, 1984;Klein Wassink, 1989;Walker and De-Haven, 1984) and may be responsible for dewetting behavior by consuming the Au reactant necessary for the wetting reaction to continue. Likewise, substantial premelting reaction will alter the subsequent flow behavior in that amounts of reactants and high-reactivity paths are diminished.…”

Section: Discussionmentioning

confidence: 99%

Dynamics of soldering reactions: Microscopic observations

Singler

Clum

Prack

1993

Microscopy Res & Technique

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This paper provides a summary of some in situ, high-resolution studies of solder spreading reactions on microelectronic circuit metallizations. Experiments are described that focus on the use of the environmental scanning electron microscope, or ESEM. Those experiments have been complemented by studies using optical hot-stage microscopy and have been supplemented by additional analytical tools such as energy dispersive X-ray microanalysis, Auger and ESCA to evaluate chemical processes. Two general results from dynamic scanning electron microscope observations are that 1) molten solder alloys undergo a segregation process during spreading in which a "precursor" film spreads in advance of the bulk solder and 2) the spreading front, which may be enriched in Sn from Pb-Sn or Bi-Sn solders, or In from Pb-In solders, spreads along high-reactivity features of the metallization surface as a reacting "precursor" film. A third observation from these tests is that, in unconfined geometries, the reactive metallization, if not sufficiently thick, can be dissolved by the solder before wetting is complete, leading to dewetting of the solder. Both the kinetics and extent of spreading of these films and the relationship of these phenomena to the commonly measured contact angle and wetting forces are currently being examined by a range of complementary techniques. Information gathered in these studies shows that process temperature as well as composition, reactivity, and relative amounts of the solder and metallization species should all be factors of interest to the those responsible for control of soldering processes.

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Ageing, Solder Thickness and Solder Alloy Effects on Circuit Board Solderability

Cited by 10 publications

References 1 publication

Oxidation of Solder Coatings

Oxidation of Solder Coatings

Microstructural evolution in the Sn-Cu-Ni and Pb-Sn solder joints with Cu and Pt-Ag metallized Al2O3 substrate

Dynamics of soldering reactions: Microscopic observations

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