Effect of Composition and Cooling Rate on the Microstructure of SnAgCu-Solder Joints

Mueller, Maik; Wiese, S.; Roellig, M.; Wolter, Klaus‐Jürgen

doi:10.1109/ectc.2007.374006

Cited by 28 publications

(16 citation statements)

References 12 publications

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“…The resulting solder spheres have diameters of 1100 µm, 590 µm, 270 µm and 130 µm. For more details on solder sphere preparation also see [1] After molding the solder spheres in epoxy resin, crosssections of the specimen have been prepared using SiC for grinding (1200 and 2400 FEPA) and diamond suspension (3 µm and 1 µm) for polishing. Final polishing was done with colloidal silica (0.05µm).…”

Section: Methodsmentioning

confidence: 99%

“…SnAgCu based lead-free solder materials have been investigated towards the mechanical and microstructural properties in a lot of studies during the last years [1][2][3]. The focus of the present study is a particular solidification phenomenon that can be found in SnAgCu based alloys.…”

Section: Introductionmentioning

confidence: 98%

“…There is a region with small grains (Fig. 1b), that is surrounded by six The lower line shows the corresponding microstructure (differential interference contrast) [1] large and areas characterized by larger grain size and three major grain orientations, which are represented by the different gray scale for contrast (black, gray, white - Fig. 1a, Fig.…”

Section: Introductionmentioning

confidence: 99%

“…1, the microstructure of a single SnAg3.0Cu0.5 solder ball (Ø 1100 μm -cooled with 1.1 K/s) is shown [1]. The solder sphere was solidified without contact to any metallization.…”

Section: Introductionmentioning

confidence: 99%

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The twinning phenomenon in SnAgCu solder balls

Mueller

Wiese

Wolter

2009

2009 59th Electronic Components and Technology Conference

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The study focuses on a particular solidification phenomenon found in SnAg3.0Cu0.5 solder balls. Investigations on the microstructure of as cast solder spheres showed, that there is an abrupt change in grain structure during solidification. The microstructure of these specimen consists of areas with small grains that are surrounded by large areas with major grain orientations. In order to characterize this phenomenon Orientation Imaging Microscopy (OIM) done by Electron Backscatter Diffraction (EBSD) has been carried out. It will be shown that the fine grains as well as the large grains show three major, distinct orientations. These measurements indicate the existence of a phenomenon, which is supposed to be caused by a twinning mechanism that creates a misorientation angle of approx. 60° between adjoining grains. In further investigations multilayer cross-sections have been carried out, in order to get a 3- dimensional overview of this phenomenon. In a third row of expe riments the influence of solder volume and composition on the twinning phenomenon has been investigated. Therefore solder spheres of different diameter (130m - 1100m) and different solder alloys (SnAg3.5; SnCu0.7; SnAg3.8Cu0.7; SnAg2.7Cu0.4Ni0.005) were analyzed. It turned out that very little change in composition cause significant changes for this phenomenon. Moreover it was discovered, that the grain structure becomes finer with decreasing volume. In a final row of experiments the influence of the metallization system on the twinning phenomenon has been investigated and the differences between the chosen metallization systems Cu/Sn and Ni/Au will be shown. The effect of individual factors like composition, cooling rate, substrate metallization and solder volume on the phenomenon will be explained and discussed in comparison to real solder joints

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

“…1, the microstructure of a single SnAg3.0Cu0.5 solder ball (Ø 1100 μm -cooled with 1.1 K/s) is shown [1]. The solder sphere was solidified without contact to any metallization.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The twinning phenomenon in SnAgCu solder balls

Mueller

Wiese

Wolter

2009

2009 59th Electronic Components and Technology Conference

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“…The fatigue life of a near eutectic SnAgCu solder joint is a function of thermal history and applied stress, and also initial solder joint microstructure. Both the Sn grain morphology and the precipitate size and number are important [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Therefore, the control and prediction of the performance and reliability of these materials would be facilitated by an understanding of the factors which affect their initial microstructure.…”

Section: Introductionmentioning

confidence: 99%

Effect of variation in the reflow profile on the microstructure of near eutectic SnAgCu alloys

Mutuku

Arfaei

Cotts

2014

2014 IEEE 64th Electronic Components and Technology Conference (ECTC)

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The effects of changes in thermal history (changes in the reflow profile) on solder joint microstructure are examined. The effects of variations in the reflow temperature, and in the cooling rate from the melt, on the microstructure of near eutectic lead free SnAgCu solder joints were investigated. Changes in precipitate or Sn grain morphologies have previously been correlated with changes in the failure rates in these Pb free alloys. Thus correlations were sought between changes in reflow parameters and in both precipitate and Sn grain morphologies. Precise reflows were conducted in a differential scanning calorimeter and it was found that changes in microstructure were correlated with large changes in the reflow temperature, and that the precipitate microstructure was a strong function of the cooling rate. This effect was similar in magnitude to that observed in relatively large changes (1 to 3wt%) in the Ag concentration of these near eutectic SnAgCu alloys.

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Scaling Effects for Miniaturized Solder Interconnects in Electronic Packages

Müller

Wolter

2012

Bio and Nano Packaging Techniques for Electron Devices

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Effect of Composition and Cooling Rate on the Microstructure of SnAgCu-Solder Joints

Cited by 28 publications

References 12 publications

The twinning phenomenon in SnAgCu solder balls

The twinning phenomenon in SnAgCu solder balls

Effect of variation in the reflow profile on the microstructure of near eutectic SnAgCu alloys

Scaling Effects for Miniaturized Solder Interconnects in Electronic Packages

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