Authors:

Hevi Medde-Witage

Date Created:

Not specified

Course Title:

Professor:

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About Paper:

Solder joints in electronic packaging undergo deformation due to thermal cycles and mechanical loads. High reflow temperatures in manufacturing cause warpage and manufacturing defects lowering the reliability of the package. Thus, it is important to develop solders with low-melting temperatures to prevent such manufacturing defects. Solder joints are vital components to ensuring reliable mechanical and electronic connections between computer board components. When solder joints deform, these electrical connections weaken, inhibiting electrical components' functionality and eventually ending the component's life cycle. Modern-day low- temperature solder joints are commonly made of eutectic Sn-Bi. Although eutectic Sn-Bi has a low melting temperature, it performs poorly at high strain rates. By improving the ductility and strength of solder joints, with the addition of alloy elements to the Sn-Bi structures, these solder joints' life cycles will increase. This project uses microstructure analysis of various solder joints that undergo aging, thermal cycling, and creep testing. Aging tests replicate the long-term behavior of solder joints and thermal cycling simulates the repeated heating and cooling of solder joints. Additionally, creep testing simulates the resistance to deformation based on a mechanical load. The microstructure analysis involves analyzing grain boundaries and intermetallic components within the solder alloy. This research aims to determine the optimal alloy structure and conditions to maximize the reliability of low-temperature solder alloys. Additionally, testing has determined that antimony and silver additions increase the ductility and strength of eutectic Sn-Bi. Aging tests have revealed the development of an intermetallic Cu6Sn5 layer and Cu3Sn layer which causes brittle failure.

Source:

Purdue University / 2023

Topics:

No topics listed

Co-authors:

Hevi Medde-Witage