Polymer based micro-transducers have many advantages over the traditional silicon based micro-transducers, such as easy integration with metal structures, design flexibility, and low fabrication costs. The characteristics of micro-transducers include converting electrical signals to/from mechanical response, the ability to sustain loading, sensitivity to external excitation, and etc. Some of the difficulties in realizing these characteristics include: characterizing material mechanical properties, techniques for producing electrically conductive polymer structures, and reliable fabrication procedures.
In this dissertation, research addressing these difficulties is presented. The developed techniques are demonstrated in the design and fabrication of a SU-8 polymer based comb-drive micro-actuator. The micro-actuator used SU-8 polymer as the main structural material and gold coating film for realizing electrical conduction. It was fabricated with multi-layer, multi-step UV-lithography technology and metallized with titled E-beam deposition and selectively electroless plating techniques.
The adhesion properties between metallic surface and SU-8 polymer were measured firstly. After comparing different metals, Au was chosen as the base material for electroplating for its good adhesion to SU-8. Customized micro-fracture toughness measurement procedure was then designed based on ASTM standards to measure the fracture toughness of Ni micro-structures.
The difficulties in micro-fabrication were then addressed. Two different approaches were evaluated for fabricating the SU-8 micro-structure: (1) multilayer processing using modified SU-8 with reduced PAG; (2) multilayer processing using normal SU-8 with copper as sacrificial layer. The second method was shown more reliable. The polymer structures were surface metallized using two methods: (1) titled E-beam deposition; (2) selectively electroless plating. The latter was proven to be more suitable for high aspect ratio sidewalls. The proper UV exposure dosage, duration, and other parameters were also established.
A novel structural design of comb drive micro-actuator was studied using analytical and finite element analysis. The design was realized with the developed fabrication technologies. Finally, the resulted micro-actuators were tested to prove the feasibility of the design and fabrication.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-11142006-015043 |
| Date | 16 November 2006 |
| Creators | Dai, Wen |
| Contributors | T. Gregory Guzik, Wanjun Wang, Jin-Woo Choi, Ashok Srivastava, Wenjing Meng |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-11142006-015043/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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