Hegde, Sudarshan and Ananthasuresh, GK (2008) Topology Optimization of Micromachined Structures with the Manufacturing Constraints of KOH Etching of (110) Silicon. In: CD-ROM proceedings of the ASME 2008 International Design Engineering Technical Conferences, Aug. 3-6, 2008, New York City, NY, USA., Aug. 3-6, 2008, New York City, NY.Full text not available from this repository.
The focus of this paper is on designing useful compliant micro-mechanisms of high-aspect-ratio which can be microfabricated by the cost-effective wet etching of (110) orientation silicon (Si) wafers. Wet etching of (110) Si imposes constraints on the geometry of the realized mechanisms because it allows only etch-through in the form of slots parallel to the wafer's flat with a certain minimum length. In this paper, we incorporate this constraint in the topology optimization and obtain compliant designs that meet the specifications on the desired motion for given input forces. Using this design technique and wet etching, we show that we can realize high-aspect-ratio compliant micro-mechanisms. For a (110) Si wafer of 250 µm thickness, the minimum length of the etch opening to get a slot is found to be 866 µm. The minimum achievable width of the slot is limited by the resolution of the lithography process and this can be a very small value. This is studied by conducting trials with different mask layouts on a (110) Si wafer. These constraints are taken care of by using a suitable design parameterization rather than by imposing the constraints explicitly. Topology optimization, as is well known, gives designs using only the essential design specifications. In this work, we show that our technique also gives manufacturable mechanism designs along with lithography mask layouts. Some designs obtained are transferred to lithography masks and mechanisms are fabricated on (110) Si wafers.
|Item Type:||Conference Paper|
|Additional Information:||Copyright of this article belongs to ASME.|
|Department/Centre:||Division of Mechanical Sciences > Mechanical Engineering|
|Date Deposited:||29 Sep 2011 09:31|
|Last Modified:||29 Sep 2011 09:31|
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