Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments
This study employed finite element analysis to simulate ultrasonic metal bump direct bonding. The stress distribution on bonding interfaces in metal bump arrays made of Al, Cu, and Ni/Pd/Au was simulated by adjusting geometrical parameters of the bumps, including the shape, size, and height; the bon...
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| Format: | Article |
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MDPI AG
2021-06-01
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| Series: | Micromachines |
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| Online Access: | https://www.mdpi.com/2072-666X/12/7/750 |
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| author | Jun-Hao Lee Pin-Kuan Li Hai-Wen Hung Wallace Chuang Eckart Schellkes Kiyokazu Yasuda Jenn-Ming Song |
| author_facet | Jun-Hao Lee Pin-Kuan Li Hai-Wen Hung Wallace Chuang Eckart Schellkes Kiyokazu Yasuda Jenn-Ming Song |
| author_sort | Jun-Hao Lee |
| collection | DOAJ |
| description | This study employed finite element analysis to simulate ultrasonic metal bump direct bonding. The stress distribution on bonding interfaces in metal bump arrays made of Al, Cu, and Ni/Pd/Au was simulated by adjusting geometrical parameters of the bumps, including the shape, size, and height; the bonding was performed with ultrasonic vibration with a frequency of 35 kHz under a force of 200 N, temperature of 200 °C, and duration of 5 s. The simulation results revealed that the maximum stress of square bumps was greater than that of round bumps. The maximum stress of little square bumps was at least 15% greater than those of little round bumps and big round bumps. An experimental demonstration was performed in which bumps were created on Si chips through Al sputtering and lithography processes. Subtractive lithography etching was the only effective process for the bonding of bumps, and Ar plasma treatment magnified the joint strength. The actual joint shear strength was positively proportional to the simulated maximum stress. Specifically, the shear strength reached 44.6 MPa in the case of ultrasonic bonding for the little Al square bumps. |
| first_indexed | 2024-03-10T10:02:05Z |
| format | Article |
| id | doaj.art-e825b2d15279464c81ef38a9ea465caf |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-03-10T10:02:05Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-e825b2d15279464c81ef38a9ea465caf2023-11-22T01:51:35ZengMDPI AGMicromachines2072-666X2021-06-0112775010.3390/mi12070750Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and ExperimentsJun-Hao Lee0Pin-Kuan Li1Hai-Wen Hung2Wallace Chuang3Eckart Schellkes4Kiyokazu Yasuda5Jenn-Ming Song6Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, TaiwanDepartment of Materials Science and Engineering, National Chung Hsing University, Taichung 402, TaiwanDepartment of Materials Science and Engineering, National Chung Hsing University, Taichung 402, TaiwanAutomotive Electronics Department, Robert Bosch Taiwan Co., Ltd., Taipei 104, TaiwanAutomotive Electronics Department, Robert Bosch Taiwan Co., Ltd., Taipei 104, TaiwanDivision of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, Osaka 565-0871, JapanDepartment of Materials Science and Engineering, National Chung Hsing University, Taichung 402, TaiwanThis study employed finite element analysis to simulate ultrasonic metal bump direct bonding. The stress distribution on bonding interfaces in metal bump arrays made of Al, Cu, and Ni/Pd/Au was simulated by adjusting geometrical parameters of the bumps, including the shape, size, and height; the bonding was performed with ultrasonic vibration with a frequency of 35 kHz under a force of 200 N, temperature of 200 °C, and duration of 5 s. The simulation results revealed that the maximum stress of square bumps was greater than that of round bumps. The maximum stress of little square bumps was at least 15% greater than those of little round bumps and big round bumps. An experimental demonstration was performed in which bumps were created on Si chips through Al sputtering and lithography processes. Subtractive lithography etching was the only effective process for the bonding of bumps, and Ar plasma treatment magnified the joint strength. The actual joint shear strength was positively proportional to the simulated maximum stress. Specifically, the shear strength reached 44.6 MPa in the case of ultrasonic bonding for the little Al square bumps.https://www.mdpi.com/2072-666X/12/7/750finite element analysisultrasonic bondingmetal direct bondingmicrosystem integration |
| spellingShingle | Jun-Hao Lee Pin-Kuan Li Hai-Wen Hung Wallace Chuang Eckart Schellkes Kiyokazu Yasuda Jenn-Ming Song Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments Micromachines finite element analysis ultrasonic bonding metal direct bonding microsystem integration |
| title | Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments |
| title_full | Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments |
| title_fullStr | Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments |
| title_full_unstemmed | Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments |
| title_short | Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments |
| title_sort | geometrical effects on ultrasonic al bump direct bonding for microsystem integration simulation and experiments |
| topic | finite element analysis ultrasonic bonding metal direct bonding microsystem integration |
| url | https://www.mdpi.com/2072-666X/12/7/750 |
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