Effects of surface properties on solder bump formation by direct droplet deposition
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
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| Format: | Thesis |
| Language: | en_US |
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Massachusetts Institute of Technology
2005
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| Online Access: | http://hdl.handle.net/1721.1/27100 |
| _version_ | 1826198533048369152 |
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| author | Hsiao, Wen Kai, 1972- |
| author2 | Jung Hoon Chun. |
| author_facet | Jung Hoon Chun. Hsiao, Wen Kai, 1972- |
| author_sort | Hsiao, Wen Kai, 1972- |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. |
| first_indexed | 2024-09-23T11:06:21Z |
| format | Thesis |
| id | mit-1721.1/27100 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:06:21Z |
| publishDate | 2005 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/271002019-04-13T00:06:55Z Effects of surface properties on solder bump formation by direct droplet deposition Hsiao, Wen Kai, 1972- Jung Hoon Chun. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Mechanical Engineering. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. Includes bibliographical references (leaves 158-162). Recent advances in microdroplet generation and deposition processes have made it possible to directly form solder bumps on integrated circuits using micron-sized molten metal droplets. The direct droplet deposition bumping process can potentially produce uniform-sized bumps more economically than the existing processes such as plating and stencil printing. However, the development of this new bumping method is still in its infancy, particularly because of a lack of understanding about the post-impact deposition behavior of molten droplets on solid targets. A deposited molten on the deposition efficiency, as well as on the final bump size and shape. The present study investigates the effects of wetting and surface roughness on droplet bouncing during solder bump formation. The potential for droplet bouncing is modeled based on the energy difference between the maximum spreading and equilibrium sessile stages of a deposited droplet. Validated by experimental results, the model shows that strong droplet-surface wetting can significantly reduce the tendency for a deposited droplet to bounce. The effect of surface droplet can sometimes recoil violently after the initial spreading and rebound off the target surface. Such behavior, known as bouncing, has a strong influence roughness on the bouncing potential is represented by the roughness-induced incomplete wetting during droplet deposition, a phenomenon quantified by a change in the effective contact area under the deposited droplet. An idealized surface model is used to represent the real surface and to describe the relationship between various roughness parameters to changes in the effective contact area. The theoretical analysis, validated by empirical data, shows that surface effective (cont.) contact area. The theoretical analysis, validated by empirical data, shows that surface roughness promotes bouncing during solder bump formation. The results from this study suggest that droplet bouncing during solder bump formation may be effectively controlled by improving the surface wetting and minimizing the substrate surface roughness. The knowledge gained is also relevant to other droplet-based manufacturing processes such as spray forming, coating, and rapid prototyping. by Wen-Kai Hsiao. Ph.D. 2005-09-06T21:44:29Z 2005-09-06T21:44:29Z 2004 2004 Thesis http://hdl.handle.net/1721.1/27100 56835672 en_US M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 166 leaves 13354521 bytes 13376541 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology |
| spellingShingle | Mechanical Engineering. Hsiao, Wen Kai, 1972- Effects of surface properties on solder bump formation by direct droplet deposition |
| title | Effects of surface properties on solder bump formation by direct droplet deposition |
| title_full | Effects of surface properties on solder bump formation by direct droplet deposition |
| title_fullStr | Effects of surface properties on solder bump formation by direct droplet deposition |
| title_full_unstemmed | Effects of surface properties on solder bump formation by direct droplet deposition |
| title_short | Effects of surface properties on solder bump formation by direct droplet deposition |
| title_sort | effects of surface properties on solder bump formation by direct droplet deposition |
| topic | Mechanical Engineering. |
| url | http://hdl.handle.net/1721.1/27100 |
| work_keys_str_mv | AT hsiaowenkai1972 effectsofsurfacepropertiesonsolderbumpformationbydirectdropletdeposition |