Effect of oxide thickness of solder powders on the coalescence of SnAgCu lead-free solder pastes

Zhang, Shasha; Zhang, Yijie; Wang, Haowei

doi:10.1016/j.jallcom.2009.08.035

Cited by 37 publications

(16 citation statements)

References 17 publications

(25 reference statements)

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“…Because of lacking a clear solder-oxide interface as in the case of TEM HAADF imaging, it is empirical to determine the thickness of the oxide layer from the O curve. Neither all oxygen [6] nor half-height method [11,14] was correct in terms of the results of TEM works ( Fig. 4 and 5).…”

Section: Resultsmentioning

confidence: 88%

“…S. Zhang etc. [11] estimated the thickness of surface oxide of solder powders with AES and found that the coalescence of solder pastes was degraded when the thickness of solder powders increased from 2.7 nm to 5.6 nm. It is shown that even a small different thickness of surface oxide of lead-free solder powders would change the performance of solder joints dramatically.…”

Section: Introductionmentioning

confidence: 99%

“…Auger Electron Spectroscopy (AES) was developed and was employed for deepness analysis of Sn oxide later. [6,11] This measurement could provide oxygen concentration-deepness curve, but the criterion of oxide thickness is arbitrary. Ref.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of accelerated surface oxidation of Sn-3.5Ag-0.5Cu solder particles by TEM and STEM

et al. 2011

2011 International Symposium on Advanced Packaging Materials (APM)

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The composition and thickness of surface oxide of solder particles has a direct effect on adhesion and electrical resistance of soldering joint and resultant the quality of interconnect and the reliability of packaged system. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) were used to examine the oxide layer on solder powders in the present paper. However, for the surface oxide layer of a lead-free solder particle, the TEM sample for the oxide layer has never been done for studying its thickness or appearance before. And it is the first time in this work to use Focus Ion Beam (FIB) technology to prepare TEM specimen for solder particles and show TEM pictures of their surface oxide layer. High angle annular dark field (HAADF) pattern was applied to distinguish between the oxide layer and the solder matrix by the contrast of average atomic number. The solder powders were exposed in air (70% relative humidity) at 150ć for 0, 120 and 240 h to simulate the accelerated growth of oxide. The surface oxide thickness was 6 nm and 50 nm measured by TEM for 0 h and 120 h samples respectively. Confirming by AES measurement, the thickness of 5 nm and 50 nm were gotten using intersection analysis method for AES depth profiles. It is found that the increase of surface oxide thickness of solder particles is proportional to the rooting of time. The elemental distribution along the oxide was quantified by line scanning using STEM and the atomic ratio of Sn to O in the oxide layer nearer to the outer, the middle, and the inner (adjacent to the solder matrix) were found to be 1:2, 2:3 and 1:1, respectively. The result was validated using XPS which gave Sn to O ratio of 1:2 at 5 nm depth of surface oxide.

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Section: Resultsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Investigation of accelerated surface oxidation of Sn-3.5Ag-0.5Cu solder particles by TEM and STEM

et al. 2011

2011 International Symposium on Advanced Packaging Materials (APM)

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“…The maximum wetting force and wetting area decrease as the thickness of the oxidation film of solder ball increases (Yahya et al , 2012). Solder balling, head-in-pillow and discoloring et al defects appear if the oxide is too thick (Nobari and Laurent, 2018; Pandher et al , 2010; Zhang et al , 2009; Cavasin, 2006). The agglomeration results in the non-uniformity of solder paste and the incomplete wetting of solder powder.…”

Section: Introductionmentioning

confidence: 99%

Effect of stearic acid coating on anti-oxidation property of Sn-Ag-Cu solder powder

Peng

Liu

Huang

et al. 2019

SSMT

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Purpose The purpose of this study is to develop a monolayer surface coating of stearic acid on Sn-Ag-Cu solder powder to limit oxidation. Design/methodology/approach Stearic acid was adsorbed onto Sn-Ag-Cu solder powder through liquid-phase adsorption. The isotherm of adsorption was measured and then the microstructure of coated powder was characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. Findings The adsorption isotherm of stearic acid on the powder was “H” type, which revealed the layer-by-layer adsorption on non-porous surface. When the concentration of solution was in the range of 0.001-0.006 mol/L, with an adsorption amount of 0.12 ± 0.1 mg/g, monolayer stearic acid covered the solder powder completely. Uniform and integrated self-assembled monolayer coating was formed through hydrogen bonds between the oxygen ions in surface lattice of Sn3.0Ag0.5Cu solder powder and the —O—H hydroxyl group of stearic acid. The maximum angle of stability of coated powder also reduced by 2.87° compared with that of non-coated powder. The increase rate of oxygen content of coated powder was much slower than that of non-coated powder when they were exposed to humid air. Originality/value As a result, oxidation of fine solder powder was effectively limited. Essentially, this method can also be applied to the coating of other types of solder powder and has reference significance to other coating by liquid-phase method.

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“…Due to this shi, the development of the ball-grid-array (BGA) and ip chips has gained momentum. [5][6][7] The increasing trend of miniaturization raises the reliability concerns. The interconnections have become ner in size, with the intentions of enhancing mechanical and electrical resistivity.…”

Section: Introductionmentioning

confidence: 99%

Effect of temperature and alloying elements (Fe and Bi) on the electrical resistivity of Sn–0.7Cu solder alloy

et al. 2016

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In this paper, we investigated the electrical resistivity as a function of temperature of the Sn-0.7Cu solder alloy with the addition of Fe and Bi. The electrical resistivity were characterized by the four-point probe method. Apparent change in electrical resistivity was witnessed by the addition of both Fe and Bi. At room temperature, the electrical resistivity was found to be increased with the addition of Fe, as well as a further increase with the addition of Bi. Fe and Bi modified Sn-0.7Cu alloys also experienced the similar increasing trend when they were subjected to higher temperatures within the range of 300-423 K. Chemical state of Sn was analyzed by means of X-ray photoelectron spectroscopy (XPS). The results revealed the presence of Sn in Sn 2+ , Sn 4+ and state of metallic Sn. With the addition of Fe & Bi, a substantial decrease was observed in the atomic percent of the Sn 4+ chemical state. X-ray diffraction (XRD) was performed on the alloys. The XRD pattern showed disturbance in the 2 theta values with the addition of Bi. The disturbance confirmed the presence of stress and imperfections in the crystal lattice. Field emission scanning electron microscope (FESEM) micrographs revealed the formation of the FeSn 2 intermetallic compound with the addition of Fe. However, the addition of Bi promotes the formation of solid solution and goes into primary b-Sn dendrites. Microstructural changes, shifts in the chemical state of Sn and a disturbance in the XRD peaks resulting from the addition of Fe and Bi have been correlated to the variation in electrical resistivity.

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Effect of oxide thickness of solder powders on the coalescence of SnAgCu lead-free solder pastes

Cited by 37 publications

References 17 publications

Investigation of accelerated surface oxidation of Sn-3.5Ag-0.5Cu solder particles by TEM and STEM

Investigation of accelerated surface oxidation of Sn-3.5Ag-0.5Cu solder particles by TEM and STEM

Effect of stearic acid coating on anti-oxidation property of Sn-Ag-Cu solder powder

Effect of temperature and alloying elements (Fe and Bi) on the electrical resistivity of Sn–0.7Cu solder alloy

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