Evaluation of Microstructures and Mechanical Properties of Sn-10Sb-Ni Lead-Free Solder Alloys with Small Amount of Ni Using Miniature Size Specimens

Abstract

Sn-Sb-Ni solder alloy is expected to be used as a die-attach material for a next-generation power semiconductors in power module. The aim of this paper is to investigate the effects of the Ni content on microstructures, tensile, and fatigue properties of Sn-10Sb-xNi (x = 0.05, 0.10, 0.25, 0.50) (mass%) lead-free solder alloys using miniature size specimens. The Sn-10Sb-Ni solder alloys have the microstructure in which Sb-Sn and Ni-Sb compounds are dispersed in the β-Sn matrix. As the Sb and Ni content increases, Sb-Sn and Ni-Sb compounds are coarsened, respectively. The effect of the Ni content on tensile properties of the alloy is slight at 25 °C. At 150 °C and 200 °C, 0.1% proof stress and tensile strength increase gradually with the Ni content increases, and saturate at the Ni amount over 0.25 mass%. According to the fatigue test at 200 °C, the fatigue properties of Sn-10Sb-Ni with 0.10–0.25 mass% Ni are better than that of the Sn-10Sb. From the experimental results, Sn-10Sb-Ni with 0.10–0.25 mass% Ni have superior mechanical properties.

Effect of Small Amount of Ni Addition on Microstructure and Fatigue Properties of Sn-Sb-Ag Lead-Free Solder

“…It was found that there are fine grains in the vicinity of the crack. As described later, in Sn with high stacking fault energy, fine grains were formed by continuous dynamic recrystallization with dynamic recovery in the thermal cycle test in the temperature range from −55 °C to 125 °C [ 38 ] and the fatigue test at 125 °C [ 23 ] and 200 °C [ 25 ]. The crack progresses at the grain boundaries of fine grains with high-angle grain boundaries [ 23 , 38 ].…”

“…scribed in Section 3.1, the addition of Ni into Sn-Sb alloys causes the formation of SbNi phases in the matrix [24][25][26]. Such SbNi phases became the origin of recrystallization, and continuous dynamic recrystallization with dynamic recovery occurred easily in Sn-6.4Sb-3.9Ag-0.4Ni.…”

“…In such next-generation semiconductors, operation temperature and surrounding environmental temperature are higher and thus the die attach materials must have improved thermal fatigue resistance. Therefore, various lead-free solders with higher solidus and liquidus temperatures than the Sn-Ag-Cu solder [ 22 , 23 , 24 , 25 , 26 , 27 ] and various nanopaste [ 28 , 29 , 30 , 31 ] have been researched to develop die attach materials with excellent thermal fatigue resistance.…”

“…We focused on Sn-Sb system alloys as high-temperature lead-free solder and investigated their mechanical properties and microstructures [ 24 , 25 , 26 ]. In particular, fatigue properties at temperatures ranging from 25 °C to 200 °C were investigated using micro-size specimens [ 8 ].…”

The Use of IR Soldering Stations in the Process of Disassembling in BGA Packaging

“…In addition, the RoHS Directive (2002/95/EC), including its amendments, which have been in force in the European Union Member States since 2006, prohibit the manufacturers of electronic and electrical equipment from using lead-type materials, which had been in use as an admixture in adhesives for many years [2,6,7,15,17].…”