Browsing by Author "Huang, Yuan-Te"

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A simulation model on photoresist SU-8 thickness after development under partial exposure with reflection effect
(2014-03-01)
Huang, Yuan-Te
;
Hsu, Wensyang
;
機械工程學系
;
Department of Mechanical Engineering
The negative photoresist SU-8 is often used to fabricate thick micro structures. It was known that reflection from the interface between SU-8 and the substrate surface would affect the thickness after development and profile of SU-8 structures. However, the model to predict the thickness after development of SU-8 under reflection effect has not been reported yet. Here, a simulation model to predict SU-8 thickness after development under partial exposure with reflection effects is proposed. Two kinds of SU-8 micro structures with different exposure dosages and coated thickness are fabricated on glass substrates to demonstrate the Capability of the proposed model. For different exposure dosages or coated SU-8 thickness, the maximum difference between simulated and experimental results is shown to be less than 3.1%, which verifies the accuracy of the proposed model. (C) 2014 The Japan Society of Applied Physics
An analytical model for calculating the pull-in voltage of micro cantilever beams subjected to tilted and curled effects
(2014-08-01)
Huang, Yuan-Te
;
Chen, He-Ling
;
Hsu, Wensyang
;
機械工程學系
;
Department of Mechanical Engineering
Pull-in is a fundamental phenomenon in electrostatic micro devices. In previous studies on modeling the pull-in voltage of suspended micro cantilever beam subject to residual stress, only curled deformation was considered. This study proposed a modified deformation function, which considered both curled and tilted deformations caused by gradient stress and mean stress, to calculate the pull-in voltage of the suspended cantilever beam with residual deformations. In order to verify the proposed analytical model, suspended poly-silicon cantilever beams with three different lengths, 260 mu m, 295 mu m and 330 mu m, are fabricated through surface micromachining process. It is shown that the residual deformations include both curled and tilted deformations, where the tilted angle and radius of curvature can be identified by white light interferometer (WLI). By comparing the analytical results with measurement results on pull-in voltages, it is found that while only considering curled effect, the average error of calculated pull-in voltage is 10.5%. On the other hand, when both tilted and curled effects are considered, the average error is reduced to 3.2%, which verifies the accuracy improvement of the proposed analytical model. (C) 2014 Elsevier B.V. All rights reserved.
Fabricating embedded SU-8 microstructures with asymmetric inside cross section by double-side multiple partial exposure method
(2014-06-01)
Huang, Yuan-Te
;
Hsu, Wensyang
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
Here a double-side multiple partial exposure (DoMPE) method is proposed to fabricate an embedded SU8 microstructure with more flexible inside cross section. The proposed method uses standard lithography equipment and needs only single-layer coating of negative photoresist SU-8 on glass substrate without bonding process. Process parameters, including development thickness at different front and back-side partial exposure doses, are experimentally characterized. Reflection effect due to Cr layer on glass substrate is shown to have influence on the development depth of SU-8 in front partial exposure. It is found that coating thicker SU-8 not only can reduce reflection effect, but also can attenuate cross-link effect due to exposure dose accumulation on SU-8 from both front and back sides. Finally, an embedded SU-8 microstructure is demonstrated to verify that the proposed DoMPE method needs only single-layer SU-8 coating to fabricate not just embedded microstructures, but also embedded microstructure with asymmetric inside cross section. (C) 2014 Elsevier B.V. All rights reserved.