Au Wire Ball Welding and Its Reliability Test for High-Temperature Environment.

Area of Science:

• Materials Science
• Sensor Technology
• Surface Engineering

Background:

• Long-term sensor application in high temperatures faces challenges in stability and reliable connections.
• Addressing these challenges is crucial for developing robust sensor systems.

Purpose of the Study:

• To systematically investigate the long-term reliability of thin gold (Au) and chromium (Cr) coatings at high temperatures.
• To understand the effects of electrode thickness, annealing temperature, and duration on coating reliability.

Main Methods:

• Deposition of Au and Cr layers on silicon substrates using magnetron sputtering.
• Annealing of samples with varying electrode thicknesses at different temperatures and durations.
• Mechanical (tensile) and electrical (probe) testing before and after annealing.
• Cross-sectional electron microscopy for bonding interface analysis.

Main Results:

• High-temperature annealing altered mechanical strength and electrical properties.
• Long-term exposure caused electrode thinning, pore formation, recrystallization, and grain growth.
• Increased gold layer thickness improved coating reliability.
• Even thin metal layers, despite degradation, remained usable.

Conclusions:

• Thin coatings exhibit degradation under prolonged high-temperature exposure due to microstructural changes.
• Optimizing electrode thickness, particularly for gold layers, is key to enhancing reliability.
• The findings provide theoretical support for applying thin coatings in high-temperature, harsh environments.