Foreword

Kang, Sung K.; Mavoori, H.; Chada, Srinivas; Kao, C. R.

doi:10.1007/s11664-001-0128-6

Cited by 10 publications

(5 citation statements)

References 0 publications

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“…1 However, with the concern of human health and nature environment, the investigation of an alternative Pb-free solder is necessary. [3][4][5][6][7][8][9][10][11][12][13][14][15] A large number of Pbfree solder alloys have been proposed, such as Sn-Ag, Sn-Bi, Sn-Ag-Bi, and Sn-Ag-Cu. The Sn-Ag-Cu system has low eutectic temperature, slow growth rate of the intermetallic layer at the interface, high strength, and a low wetting angle.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cu concentration on morphology of Sn-Ag-Cu solders by mechanical alloying

Kao

Duh

2004

Journal of Elec Materi

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The mechanical alloying (MA) process is considered an alternative approach to produce solder materials. In this study, the effect of Cu concentration in the ternary Sn-3.5Ag-xCu (x ϭ 0.2, 0.7, and 1) solder by MA was investigated. The (Cu,Sn) solid solution was precipitated as the Cu 6 Sn 5 intermetallic compound (IMC), which was distributed nonuniformly through the microstructure. The Cu 6 Sn 5 IMC, which was present in the SnAgCu solder with high Cu composition, causes the as-milled MA particle to fracture to a smaller size. Appreciable distinction on morphology of as-milled MA powders with different Cu content was revealed. When the Cu concentration was low (x ϭ 0.2), MA particle aggregated to a spherical ingot with large particle size. For higher Cu concentration (x ϭ 0.7 and x ϭ 1), the MA particle turned to flakes with smaller particle size. The distinction of the milling mechanism of Sn-3.5Ag-xCu (x ϭ 0.2, 0.7, and 1) solder by the MA process was discussed. An effective approach was developed to reduce the particle size of the SnAgCu solder from 1 mm down to 10-100 µm by doping the Cu 6 Sn 5 nanoparticle during the MA process. In addition, the differential scanning calorimetry (DSC) results also ensure the compatibility to apply the solder material for the reflow process.

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Section: Introductionmentioning

confidence: 99%

Effect of Cu concentration on morphology of Sn-Ag-Cu solders by mechanical alloying

Kao

Duh

2004

Journal of Elec Materi

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“…Several promising lead-free solders to replace Pbcontaining solders in microelectronic applications have been identified. [1][2][3][4][5][6][7][8][9][10][11][12][13] They include Sn-3.5Ag, Sn-0.7Cu, Sn-3.8Ag-0.7Cu, Sn-3.5Ag-4.8Bi, and Sn8Zn-3Bi among others (in weight percent). These lead-free solders are all tin-rich with a melting point between 190°C and 227°C.…”

Section: Introductionmentioning

confidence: 99%

Effects of mechanical deformation and annealing on the microstructure and hardness of Pb-free solders

Lauro

Kang

Choi

et al. 2003

Journal of Elec Materi

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The microstructure property relations of several Pb-free solders are investigated to understand the microstructural changes during thermal and mechanical processes of Pb-free solders. The Pb-free solder alloys investigated include pure Sn, Sn-0.7% Cu, Sn-3.5% Ag, and Sn-3.8% Ag-0.7% Cu (in weight percent). To reproduce a typical microstructure observed in solder joints, the cooling rate, ingot size, and reflow conditions of cast alloys were carefully controlled. The cast-alloy pellets are subjected to compressive deformation up to 50% and annealing at 150°C for 48 h. The microstructure of Pb-free solders is evaluated as a function of alloy composition, plastic deformation, and annealing. The changes in mechanical property are measured by a microhardness test. The work hardening in Sn-based alloys is found to increase as the amount of alloying elements and/or deformation increases. The changes in microhardness upon deformation and annealing are correlated with the microstructural changes, such as recrystallization or grain growth, in Pb-free solder alloys.

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“…[1][2][3][4][5][6][7][8][9][10][11][12] The candidates include Sn-3.5Ag (SA), Sn-3.5Ag-0.7Cu (SAC), Sn-3.5Ag-4.8Bi (SAB), and Sn-0.7Cu (with slight variations in composition). Although a considerable amount of publications on Pbfree solders can be found in the recent literature, 13,14 research is still at the infancy stage as compared to the vast amount of data accumulated for the Pbcontaining solders over the last several decades. [15][16][17] In this study, we investigated the mechanical and electrical properties of several Pb-free solder joints as a function of their interfacial reactions, namely, the intermetallic compound (IMC) thickness and morphology.…”

Section: Introductionmentioning

confidence: 99%