The Effect of Eutectic Structure on the Creep Properties of Sn-3.0Ag-0.5Cu and Sn-8.0Sb-3.0Ag Solders

Abstract

Solder joints are the main weak points of power modules used in harsh environments. For the power module of electric vehicles, the maximum operating temperature of a chip can reach 175 • C under driving conditions. Therefore, it is necessary to study the high-temperature reliability of solder joints. This study investigated the creep properties of Sn-3.0Ag-0.5Cu (SAC305) and Sn-8.0Sb-3.0Ag (SSA8030) solder joints. The creep test was conducted at 175 and 190 • C with the application of 2.45 MPa. The SAC305 solder had superior creep properties to those of SSA8030 solder at 175 • C and at largely the same homologous temperature (T H~0 .91 for SAC305 and T H~0 .92 for SSA8030). Both solders had primary β-Sn and a eutectic mixture of β-Sn and Ag 3 Sn. Compared to SSA8030, the SAC305 solder contained~10% more eutectic structure and contained Ag 3 Sn that was 3 times smaller and more round in shape. Furthermore, the SSA8030 solder precipitated SnSb in an elongated fiber shape (1-50 µm in size) after the creep test. Coarse and elongated Ag 3 Sn and SnSb of the SSA8030 solder negatively affected crack propagation in the dislocation creep region and decreased the creep resistance.

Microstructure and properties of Sn-Ag and Sn-Sb lead-free solders in electronics packaging: a review

“…Sn-5Sb-1.5Au solder had higher creep resistance and fracture life compared with Sn-5Sb and Sn-5Sb-3.5Ag, mainly because hard AuSn 4 IMC hindered the dislocation movement to a large extent [31]. Park et al [112] researched the creep properties of Sn-8.0Sb-3.0Ag by the creep experiment which was carried out at 175 °C under the load of 2.45 MPa on Sn-8.0Sb-3.0Ag solder. It was found that the Sn-8.0Sb-3.0Ag solder will form a slender Ag 3 Sn structure, and Ag 3 Sn can inhibit the dislocation movement, thereby improving the creep resistance of the solder.…”

Microstructure and Mechanical Properties of Structural Metals and Alloys

“…The major portion of these papers is focused on the mechanisms of microstructure evolution and the mechanical properties of metallic materials subjected to various thermo-mechanical, deformation, or heat treatments [1][2][3][4][5][6][7][8][9][10][11][12]. Another large portion of the studies is aimed on the elaboration of alloying design of advanced steels and alloys [13][14][15][16]. The changes in phase content, transformation, and particle precipitation and their effect on the properties are also broadly presented in this collection [17][18][19][20][21].…”

“…As a guest editor, I have the pleasure to note that present collection is not limited to such frequently used materials like steel and aluminum alloys. Interested readers will find attractive reports on magnesium [1], nickel [3], titanium [4,5], copper [6,11], and tin [14] alloys. Those who are interested in innovative materials, and their processing and applications, are suggested to take a good look at Ti/TiB metal-matrix composite [5] and high-entropy alloys [9].…”

The Interface Microstructure and Shear Strength of Sn2.5Ag0.7Cu0.1RExNi/Cu Solder Joints under Thermal-Cycle Loading

“…Park et al investigated the creep properties of Sn3.0Ag0.5Cu (SAC305) solder to study the high-temperature reliability of solder joints. The results show that the SAC305 solder has superior creep properties to those of Sn8.0Sb3.0Ag solder at 175 • C [18]. Li et al investigated IMCs growth of Sn-3.0Ag-0.5Cu/Cu solder joint during isothermal aging, thermal cycling, and thermal shock.…”