Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packaging
This study addresses the critical challenge of achieving low-temperature Cu–Cu bonding for advanced packaging applications by optimizing area-selective electroless Au passivation. We demonstrate that an Ar/N2 plasma pretreatment, applied prior to Au deposition, substantially strips oxides, renders t...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-05-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425011950 |
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| author | Mu-Ping Hsu Chi-Yu Chen Hsin-Chi Chang Kuan-Neng Chen |
| author_facet | Mu-Ping Hsu Chi-Yu Chen Hsin-Chi Chang Kuan-Neng Chen |
| author_sort | Mu-Ping Hsu |
| collection | DOAJ |
| description | This study addresses the critical challenge of achieving low-temperature Cu–Cu bonding for advanced packaging applications by optimizing area-selective electroless Au passivation. We demonstrate that an Ar/N2 plasma pretreatment, applied prior to Au deposition, substantially strips oxides, renders the Cu surface amorphous and highly hydrophilic, and thus suppresses grain-boundary-selective Au displacement to form a smooth, continuous passivation layer. The resulting amorphous Cu surface layer facilitates the formation of continuous Au films without “lightning-like” patterns, enabling reliable chip-to-chip bonding at temperatures as low as 150 °C under ambient conditions. Compared to O2 or N2-only plasma treatments, the Ar/N2 approach yields stronger bonds, improved void filling by Cu diffusion, and higher electrical yields and stability. These findings underscore the importance of pretreatment engineering in electroless plating processes, paving the way for more robust, scalable, and cost-effective Cu–Cu bonding solutions in next-generation advanced packaging. |
| format | Article |
| id | doaj-art-79ee7a66336d46779b775ace52eef836 |
| institution | Kabale University |
| issn | 2238-7854 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj-art-79ee7a66336d46779b775ace52eef8362025-08-20T03:52:55ZengElsevierJournal of Materials Research and Technology2238-78542025-05-01367748775410.1016/j.jmrt.2025.05.041Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packagingMu-Ping Hsu0Chi-Yu Chen1Hsin-Chi Chang2Kuan-Neng Chen3Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, TaiwanInstitute of Pioneer Semiconductor Innovation, National Yang Ming Chiao Tung University, Hsinchu, TaiwanInstitute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, TaiwanInstitute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan; Institute of Pioneer Semiconductor Innovation, National Yang Ming Chiao Tung University, Hsinchu, Taiwan; Corresponding author. Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan.This study addresses the critical challenge of achieving low-temperature Cu–Cu bonding for advanced packaging applications by optimizing area-selective electroless Au passivation. We demonstrate that an Ar/N2 plasma pretreatment, applied prior to Au deposition, substantially strips oxides, renders the Cu surface amorphous and highly hydrophilic, and thus suppresses grain-boundary-selective Au displacement to form a smooth, continuous passivation layer. The resulting amorphous Cu surface layer facilitates the formation of continuous Au films without “lightning-like” patterns, enabling reliable chip-to-chip bonding at temperatures as low as 150 °C under ambient conditions. Compared to O2 or N2-only plasma treatments, the Ar/N2 approach yields stronger bonds, improved void filling by Cu diffusion, and higher electrical yields and stability. These findings underscore the importance of pretreatment engineering in electroless plating processes, paving the way for more robust, scalable, and cost-effective Cu–Cu bonding solutions in next-generation advanced packaging.http://www.sciencedirect.com/science/article/pii/S22387854250119503DICAdvanced packagingArea selective depositionLow temperature Cu–C bondingElectroless plating |
| spellingShingle | Mu-Ping Hsu Chi-Yu Chen Hsin-Chi Chang Kuan-Neng Chen Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packaging Journal of Materials Research and Technology 3DIC Advanced packaging Area selective deposition Low temperature Cu–C bonding Electroless plating |
| title | Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packaging |
| title_full | Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packaging |
| title_fullStr | Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packaging |
| title_full_unstemmed | Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packaging |
| title_short | Achieving low-temperature Cu–Cu bonding platform via area-selective metal films with superior surface roughness for advanced packaging |
| title_sort | achieving low temperature cu cu bonding platform via area selective metal films with superior surface roughness for advanced packaging |
| topic | 3DIC Advanced packaging Area selective deposition Low temperature Cu–C bonding Electroless plating |
| url | http://www.sciencedirect.com/science/article/pii/S2238785425011950 |
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