Investigation into the evolution and failure mechanism of IMCs in Au wire bond interconnections under long-term wet heat conditions
This research analyzed the microstructure evolution, defect formation, and mechanical performance degradation mechanism of the bonding wire and Au-/Al interface with long-term exposure to 85 °C/85 %RH thermal-humidity bias (THB). The results showed that intermetallic compound (IMC) mainly appeared a...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425020708 |
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| Summary: | This research analyzed the microstructure evolution, defect formation, and mechanical performance degradation mechanism of the bonding wire and Au-/Al interface with long-term exposure to 85 °C/85 %RH thermal-humidity bias (THB). The results showed that intermetallic compound (IMC) mainly appeared at the Au-/Al interface, initially composed of AuAl and Au2Al, and transformed into Au4Al after THB, with a small amount of Au8Al3 phase present. The formation of IMC was attributed to the mutual diffusion of Au and Al. The wet heat environment accelerated the formation of IMC. The average thickness of IMC increased the fastest after 200 h THB. With the extension of the aging time, the growth rate of IMC gradually decreased, following the power function law. After THB, irregular particles containing Ag appeared on the surface of the Au wire, and the particles gradually moved from the second joint to the first joint as the aging continued. The mechanical performance results indicated that excessive IMCs, cracks, and voids at the interface deteriorated the mechanical properties of the Au wire bonds. The average maximum tensile force decreased by 62.42 %, and the average fracture energy also decreased by 49.35 %. The failure mode changed from wire fracture to bond ball detachment. This research explored the evolution of IMCs, element diffusion, and failure mechanism of bonding joints in the long-term wet heat environment, established the IMC growth rate equation and Au wire bonding electrochemical corrosion model, which is helpful for promoting further understanding in the field of metal wire bonding materials research and application. |
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| ISSN: | 2238-7854 |