Abstract
In this study, soldering is conducted between a chip and a CLCC-3 shell base with a sheet-like AuGa0.03 alloy solder as the encapsulating material. X-ray images of chip soldering samples, XRD diffraction analysis of the joints, SEM images reflecting the microstructures of the joints, and EDS of the cross sections of the chip soldering samples show that with gradually increasing soldering temperature, the phase composition is not affected, and all the joint structures are an Au + Si eutectic structure; the Au–Si eutectic reaction occurs during the soldering process. No deposition of meta-stable phases, such as Au7Si, Au5Si, or Au3S, is found. A soldering temperature of 420 °C can reduce the negative impacts of secondary cap welding soldering on the joint and improve the structure and mechanical properties of the joint.
Highlights
Along with the ongoing development of very large scale integration (VLSI) and miniaturized chip components, the encapsulation and assembly of circuits or systems has been used to realize high performance and the small form factor (SFF) in electronic components and systems [1,2,3,4]
1. surface, high was measure the temperature theFigure heating and the temperature was with controlled stability was used to measure the temperature of the heating surface, and the temperature was by the deep-cavity eutectic soldering table
The joint close to the chip has an Au + Si eutectic structure, no compounds formed from other metals, and some holes distributed therein due to the large density difference between the Au–Si liquid phase (18.64 g/cm3) and Si (2.33 g/cm3)
Summary
Along with the ongoing development of very large scale integration (VLSI) and miniaturized chip components, the encapsulation and assembly of circuits or systems has been used to realize high performance and the small form factor (SFF) in electronic components and systems [1,2,3,4]. The reliability demands on electronic components in the rapidly developing aerospace and avionics industry are increasing With this trend, hermetically welded seams have been widely used by the military for their high reliability [5,6]. For a long period of time, more tin–lead eutectic and hypo-eutectic solders were used for encapsulation; lead is a toxic metal element in these solders that is hazardous to humans and the environment [13,14,15,16,17] To resolve this problem, gold-based solders [18,19] are a good substitution for the encapsulation of semiconductor components. Gold-based solders have anti-corrosion 2and anti-oxidation properties and good fluidity, and are stable under high temperatures.
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