Low-temperature copper–copper quasi-direct bonding with cobalt passivation layer
In this work, an ultra-thin cobalt film is used as a passivation layer to achieve a Cu–Cu quasi-direct bonding process, and successful bonding was achieved at the bonding temperature of 230 °C with the bonding pressure of 0.5 MPa in non-vacuum conditions. A tensile bonding strength of over 12.8 MPa...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2022-11-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/5.0108693 |
| _version_ | 1828058437015044096 |
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| author | Peng Wang Yun-Hao Shao Zi-Hong Ni Chun-Feng Hu Xin-Ping Qu |
| author_facet | Peng Wang Yun-Hao Shao Zi-Hong Ni Chun-Feng Hu Xin-Ping Qu |
| author_sort | Peng Wang |
| collection | DOAJ |
| description | In this work, an ultra-thin cobalt film is used as a passivation layer to achieve a Cu–Cu quasi-direct bonding process, and successful bonding was achieved at the bonding temperature of 230 °C with the bonding pressure of 0.5 MPa in non-vacuum conditions. A tensile bonding strength of over 12.8 MPa can be achieved. With the cobalt layer, the total film roughness is greatly reduced to around 1 nm, and the cross-sectional transmission electron microscope images reveal the presence of a void-free bonding interface. Time-of-flight secondary ion mass spectrometry depth analysis is carried out using a PVD deposited multilayer sample, which simulates the bonding process without pressure. It is found that a Cu–Co intermixing layer formed between the Cu and Co interfaces during annealing, and Cu has diffused into the Co layer. Due to the nanocrystalline structure of the Co film and the low roughness of the system, a low bonding temperature can be achieved. These results demonstrate that Co, which can be selectively grown on the Cu surface, can be used as a passivation layer to achieve low-cost and high-quality interconnect for the three-dimensional integrated circuits. |
| first_indexed | 2024-04-10T21:27:08Z |
| format | Article |
| id | doaj.art-67b61b8b5f5d47b8a0161a25e0ebed42 |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-04-10T21:27:08Z |
| publishDate | 2022-11-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-67b61b8b5f5d47b8a0161a25e0ebed422023-01-19T16:29:02ZengAIP Publishing LLCAIP Advances2158-32262022-11-011211115101115101-810.1063/5.0108693Low-temperature copper–copper quasi-direct bonding with cobalt passivation layerPeng Wang0Yun-Hao Shao1Zi-Hong Ni2Chun-Feng Hu3Xin-Ping Qu4State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, 220 Handan Rd., Shanghai 200433, ChinaState Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, 220 Handan Rd., Shanghai 200433, ChinaState Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, 220 Handan Rd., Shanghai 200433, ChinaState Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, 220 Handan Rd., Shanghai 200433, ChinaState Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, 220 Handan Rd., Shanghai 200433, ChinaIn this work, an ultra-thin cobalt film is used as a passivation layer to achieve a Cu–Cu quasi-direct bonding process, and successful bonding was achieved at the bonding temperature of 230 °C with the bonding pressure of 0.5 MPa in non-vacuum conditions. A tensile bonding strength of over 12.8 MPa can be achieved. With the cobalt layer, the total film roughness is greatly reduced to around 1 nm, and the cross-sectional transmission electron microscope images reveal the presence of a void-free bonding interface. Time-of-flight secondary ion mass spectrometry depth analysis is carried out using a PVD deposited multilayer sample, which simulates the bonding process without pressure. It is found that a Cu–Co intermixing layer formed between the Cu and Co interfaces during annealing, and Cu has diffused into the Co layer. Due to the nanocrystalline structure of the Co film and the low roughness of the system, a low bonding temperature can be achieved. These results demonstrate that Co, which can be selectively grown on the Cu surface, can be used as a passivation layer to achieve low-cost and high-quality interconnect for the three-dimensional integrated circuits.http://dx.doi.org/10.1063/5.0108693 |
| spellingShingle | Peng Wang Yun-Hao Shao Zi-Hong Ni Chun-Feng Hu Xin-Ping Qu Low-temperature copper–copper quasi-direct bonding with cobalt passivation layer AIP Advances |
| title | Low-temperature copper–copper quasi-direct bonding with cobalt passivation layer |
| title_full | Low-temperature copper–copper quasi-direct bonding with cobalt passivation layer |
| title_fullStr | Low-temperature copper–copper quasi-direct bonding with cobalt passivation layer |
| title_full_unstemmed | Low-temperature copper–copper quasi-direct bonding with cobalt passivation layer |
| title_short | Low-temperature copper–copper quasi-direct bonding with cobalt passivation layer |
| title_sort | low temperature copper copper quasi direct bonding with cobalt passivation layer |
| url | http://dx.doi.org/10.1063/5.0108693 |
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