A numerical method for predicting intermetallic layer thickness developed during the formation of solder joints

Schaefer, M.; Laub, W.; Sabee, Janet M.; Fournelle, R.A.; Lee, Ping S.

doi:10.1007/bf02666735

Cited by 56 publications

(43 citation statements)

References 14 publications

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“…[18,19] We will show that for a stoichiometric intermetallic phase, reaction leads to a linear growth behavior, d / t. For mixed modes of diffusion and reaction, the growth factor is between 1/2 and 1. This finding is contrary to the existing relation, [20,21] d / t n , n 1/2. (ii) Secondly, the existing works explain the formation of the sandwich-like structure by nucleation and grain growth theories.…”

Section: Introductioncontrasting

confidence: 91%

Numerical and Experimental Investigations on the Growth of the Intermetallic Mg₂Si Phase in Mg Infiltrated Si‐Foams

et al. 2017

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The present work explores the growing behavior of the intermetallic layer in the Mg-Si system. Following achievements have been obtained in our investigation: (i) A complete wetting concept is proposed for the lateral spreading of the intermetallic layer. (ii) In contrast to the stoichiometric property for the intermetallic phase in the phase diagram, the authors show that concentration gradients are able to be established in the kinetic process. (iii) Contrary to the reported growth behavior, d / t 0.25-0.5 in other intermetallics, the authors find a transition from d / ffiffi t p to d / t with an increase of the temperature, where d is the thickness of the intermetallic layer and t is the time.

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Section: Introductioncontrasting

confidence: 91%

Numerical and Experimental Investigations on the Growth of the Intermetallic Mg₂Si Phase in Mg Infiltrated Si‐Foams

et al. 2017

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“…Time exponents of the growth curve measured with eutectic Sn-Pb solder on a Cu pad, however, were significantly different from the theoretical values, ranging from 0.21 to 0.37. [1][2][3][4][5] These results indicate that neither the volumetric diffusion through the layer nor the reaction at the interface is the rate-controlling step of the intermetallic layer formation reaction. In addition, the wide variation in time-exponent values might be an indication of varying rate-controlling steps depending on the conditions of reflow soldering.…”

Section: Introductionmentioning

confidence: 97%

Kinetics of intermetallic formation at Sn-37Pb/Cu interface during reflow soldering

Lee

Kim

2002

Journal of Elec Materi

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INTRODUCTIONThe growth of intermetallic layers at the solder/contact pad interface is an important concern in microelectronic packages, as the reliability of the solder interconnection may be degraded by their growth. It has been noted during reflow soldering of Sn-based solder on a Cu pad that the growth of Cu 6 Sn 5 and Cu 3 Sn intermetallic layers cannot be described accurately as a parabolic function of reflow time. Instead, the growth was predicted well with power-law kinetics. When the growth kinetics of a layer are controlled by volumetric diffusion through the planar intermetallic layer, the time exponent should be 1/2, and when controlled by chemical reaction at the interface, the exponent should be 1.0. Time exponents of the growth curve measured with eutectic Sn-Pb solder on a Cu pad, however, were significantly different from the theoretical values, ranging from 0.21 to 0.37. 1-5 These results indicate that neither the volumetric diffusion through the layer nor the reaction at the interface is the rate-controlling step of the intermetallic layer formation reaction. In addition, the wide variation in time-exponent values might be an indication of varying rate-controlling steps depending on the conditions of reflow soldering.A number of studies have been conducted to investigate the causes of such nonparabolic growth behaviors. Several authors claim that channels between scalloplike grains filled with liquid solder or coarsening of grains in the intermetallic layer are responsible for such behavior. 2-4,6-10 The channels were found to form as a result of wetting of grain boundaries by liquid-phase solders 11 and may serve as a fast mass-transport route for the formation reaction. Coarsening of the grains reduces the area fractions of the channel and of the grain boundary, which is also a fast mass-transport route.The coarsening kinetics of grains in the intermetallic layer during reflow soldering are complicated because of the presence of mass fluxes originating not only from the Gibbs-Thompson effect but also from Cu dissolution. Kim and Tu 9 analyzed the coarsening of scalloplike grains during reflow soldering by considering two types of mass fluxes, namely, reaction and ripening flux. The reaction flux denotes the mass flux of Cu through the channel, driven by the Cu-concentration gradient. The Cu dissolves at the bottom of the channel, where the solder and the Cu pad are in direct contact. The Cu atoms diffuse through the channel and react with Sn at the surface of the layer to increase the thickness of the intermetallic layer, i.e., reaction flux. The ripening flux denotes the mass flux driven by the Gibbs-Thompson effect. The coarsening behavior of scalloplike grains predicted from the two types of mass fluxes was in good agreement with experimental measurements. 6The kinetics of the intermetallic layer formation at Sn-37wt.%Pb solder/Cu pad interface during reflow soldering were studied. The growth kinetics were analyzed theoretically by assuming that the mass flux of Cu through channels between ...

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“…Typical soldering of copper consists of (i) eutectic melting (reflow) of solder bump and (ii) reaction of molten solder with substrate leading to formation and growth of one or two intermetallics, g-Cu 6 Sn 5 phase and e-Cu 3 Sn phase [3][4][5][6][7][8][9][10]. Mechanical bonding is provided mainly by g-phase, which has peculiar morphology-scallops of individual grains separated by some boundaries, nature of which is still under discussion-liquid channels of molten solder [8,9,11], prewetted grain boundaries [12], ordinary grain boundaries [13,14].…”

Section: Introductionmentioning

confidence: 99%

Phase growth competition in solid/liquid reactions between copper or Cu3Sn compound and liquid tin-based solder

Liashenko

Гусак

Hodaj

2014

J Mater Sci: Mater Electron

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International audienceInterfacial reaction between solid e-Cu3Sn compound and liquid Sn at 250 °C is studied for the first time. The reaction product formed at the e-Cu3Sn/liquid Sn interface consists of the single g-Cu6Sn5 phase. The growth kinetics of the g phase formed at the incremental e/liquid Sn couple (e/g/Sn configuration) is compared to that of g phase formed at the classical Cu/liquid Sn couple (Cu/e/g/Sn configuration). The experimental method con- sists first in processing of intimate interfaces by dipping peaces of solid e-Cu3Sn compound and Cu in liquid Sn for 1 s at 250 °C. Afterwards, isothermal holding of such pre- performed couples for 10, 30, 120 and 480 min at 250 °C are performed for both couples. A theoretical analysis of the growth kinetics of g phase and comparison of its in both configurations are performed

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A numerical method for predicting intermetallic layer thickness developed during the formation of solder joints

Cited by 56 publications

References 14 publications

Numerical and Experimental Investigations on the Growth of the Intermetallic Mg₂Si Phase in Mg Infiltrated Si‐Foams

Numerical and Experimental Investigations on the Growth of the Intermetallic Mg₂Si Phase in Mg Infiltrated Si‐Foams

Kinetics of intermetallic formation at Sn-37Pb/Cu interface during reflow soldering

Phase growth competition in solid/liquid reactions between copper or Cu3Sn compound and liquid tin-based solder

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A numerical method for predicting intermetallic layer thickness developed during the formation of solder joints

Cited by 56 publications

References 14 publications

Numerical and Experimental Investigations on the Growth of the Intermetallic Mg2Si Phase in Mg Infiltrated Si‐Foams

Numerical and Experimental Investigations on the Growth of the Intermetallic Mg2Si Phase in Mg Infiltrated Si‐Foams

Kinetics of intermetallic formation at Sn-37Pb/Cu interface during reflow soldering

Phase growth competition in solid/liquid reactions between copper or Cu3Sn compound and liquid tin-based solder

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Numerical and Experimental Investigations on the Growth of the Intermetallic Mg₂Si Phase in Mg Infiltrated Si‐Foams

Numerical and Experimental Investigations on the Growth of the Intermetallic Mg₂Si Phase in Mg Infiltrated Si‐Foams