Page 59 - MEMS Mechanical Sensors

48 MEMS Simulation and Design Tools

3.2.2.2 IntelliSuite

Intellisense Corning commercialized the MEMS CAD package IntelliSuite, current
version 7.1 [10]. It also is a FEM-based simulation and design tool specifically devel-
oped for MEMS and runs on a standard PC under Windows. The user starts by
drawing the masks in IntelliMask, which is a standard drawing package with typical
features for mask designs such as multiple translations copy, layer control, and hier-
archical cells. Each mask is drawn on a separate layer and saved in a different file. It
is also possible to import and export the masks in GDS II of DXF file format. The
next step is to define the fabrication process in a tool called IntelliFab. It contains a
large database of silicon base materials, deposition steps of various materials, and
etching steps for all commonly used materials in MEMS. The previously defined
masks are used to define areas in which material is removed or added. Once the user
has created the full process flow (referred to as Process Table) IntelliFab visualizes
the fabricated device in an easy-to-use viewer that allows zooming, panning, and
three-dimensional rotation of the virtual prototype. For standard MEMS processes,
templates are available. The properties of a material used in any process step can be
defined and altered in a powerful tool called MEMaterial. If, for example, one
process step is to deposit silicon nitride (Si N ) in a PECVD furnace, material proper-
3 4
ties include stress, density, thermal expansion coefficient, Young’s modulus, and
Poisson’s ratio. If the material property is not a constant but depends on one or sev-
eral fabrication conditions, their relationship may be graphically displayed. Stress of
silicon nitride, for instance, depends on the deposition temperature, and their rela-
tionship is shown in the graph in the top-right window of Figure 3.7. In the lower

Figure 3.7 The MEMaterial tool within IntelliSuite. The user can graphically view and change
material properties as a function of fabrication process parameters.