A low power, tight seal, polyimide electrostatic microvalve Page: 6 of 10
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
The critical voltage that causes the cantilever to roll flat onto the substrate is derived in
2 Eh3 d p d,
12R2( op en
where Vc is the critical voltage, E is the equivalent Youn'g modulus of the multilayer can-
tilever, h is the thickness, d and E are the dielectric gap and dielectric constants of polyim-
ide and silicon nitride, and R is the radius of curvature of the curled cantilever. For the
microvalve, the thin film layers layers are illustrated in Fig. 1(d). The bottom-most layer is
du Pont polyimide PI2611 and the thickness is 0.08 gm, the metal layer Ti/Au is 0.15 gm,
the second PI2611 is 1.5 pm, and the top-most layer is du Pont PI2555 with a thickness of
2.5 m. The thickness of the insulating silicon nitride is 0.1 pm. The effective Young's
modulus is 3GPa and the initial curvature is 294 m. The dielectric constants of PI2611 and
nitride are 3.3 and 8, respectively. With these dimensions, Eq(1) gives us a critical voltage
VC = 35V.
FIGURE 2. Finite element analysis of residual stress generated initial curvature.
Cantilever beam is 500 gm long and 200 gm wide, with
The width and length of the cantilever was 200 gm and 500 jm, respectively. For the
design of the initial curvature in the cantilever, since there are four layers in the cantilever
and the width-to-length ration is much greater than 0.1, finite element analysis using
Abaqus was used instead of deriving an analytical solution. Figure 2 shows the finite ele-
ment analysis results of the multilayer indicating the resultant opening of the cantilever
caused by the built-in residual stress in the polyimide/Au/Ti thin film design. The resulting
IMECE 1996 paper
Here’s what’s next.
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Lee, A.P.; Hamilton, J. & Trevino, J. A low power, tight seal, polyimide electrostatic microvalve, article, April 17, 1996; California. (https://digital.library.unt.edu/ark:/67531/metadc686540/m1/6/: accessed March 24, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.