The possibility of using residual stresses favorably as a means of self-assembling
MEMS during material deposition is experimentally investigated. Two atomic force
microscope cantilevers are placed in contact at their free ends. Material is isothermally
electroplated onto one (the deposition) cantilever, but no material is deposited onto the
other (spring) cantilever. The deposited layer contains residual stresses that deform the
deposition cantilever. The deposition cantilever in turn deforms the spring cantilever,
thereby doing work in the spring cantilever and proving that the two structures can selfassemble
during deposition processing. An insoluble nickel electroplating process and an
all-sulfate nickel solution are used for the deposition. The deflection of the selfassembled
cantilevers is measured in-situ as a function of the deposited thin film
thickness through the optical method of atomic force microscopy.
The experimental results are compared to an analytical model which consists of
Euler-Bernoulli beam theory that is modified to account for moving boundaries as the material is deposited. The model accounts for the through-thickness variation of the
intrinsic strain during the electroplating. Closed-form solutions are not possible, but
numerical solutions are plotted for the cantilever deflection and work on the spring
cantilever as functions of the deposition thickness.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2507 |
| Date | 01 November 2005 |
| Creators | Kim, Sang-Hyun |
| Contributors | Boyd, James G. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 4896967 bytes, electronic, application/pdf, born digital |
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