Effects of Trace Oxygen Content on Microstructure and Performances of Au-20Sn/Cu Solder Joints
| Autor: | Di Wu, Yabin Zhang, Songbai Xue, Yang Li, Liujue Wang |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
fluxless packaging General Chemical Engineering chemistry.chemical_element 02 engineering and technology 01 natural sciences Oxygen Inorganic Chemistry High oxygen 0103 physical sciences Shear strength General Materials Science shear strength Oxygen content 010302 applied physics Crystallography Metallurgy Au-20Sn solder 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure trace oxygen content Substrate (building) chemistry QD901-999 Soldering ratio of soldering area gas tightness Wetting 0210 nano-technology |
| Zdroj: | Crystals Volume 11 Issue 6 Crystals, Vol 11, Iss 601, p 601 (2021) |
| ISSN: | 2073-4352 |
| DOI: | 10.3390/cryst11060601 |
| Popis: | The Au-20Sn solder is widely used in the packaging of high-end electronic products, and the requirement on the reliability of the solder joints is more and more strict with a continuous increase in the performance of the package products. As the oxygen content in the Au-Sn solder is a key factor dominating the quality of fluxless packaging, in this study, the wettability and spreading performance of the Au-20Sn solder with different oxygen contents and the interfacial microstructure, mechanical properties, gas tightness and ratio of soldering area of the Au-Sn/Cu solder joints prepared using these solders were comprehensively investigated to clarify the effects of trace oxygen content. The results reveal that the wetting and spreading performances of the solder decrease sharply with increasing oxygen conte[nt. When the oxygen content increased from 18 to 77 ppm, the spreading area of the solder on the Cu substrate decreased from 92.8 to 49.2 mm2, reducing by 47%. Meanwhile, pores and microcracks appear in the solder joint with relatively high oxygen content, making the shear strength decrease from 56.6 to 31.7 MPa. The oxygen also greatly affects the gas tightness and ratio of soldering area. For the optical window packaged using Au-Sn solder containing 40 ppm of oxygen, the leakage rate was higher than 5 × 10−11 mbar·m−3·s−1 and cannot fulfill the requirements. With increasing oxygen content in the Au-Sn solder, the cleanliness of the chip packaged with these solders deteriorated, and the solder surface was obviously oxidized. When the oxygen content was 18 ppm, the ratio of soldering area was 92%, but decreased sharply to 53% when the oxygen content increased to 77 ppm. It is demonstrated that an oxygen content lower than 27 ppm is required for the Au-20Sn solder used in fluxless packaging. |
| Databáze: | OpenAIRE |
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