文档介绍：Iterative ic/Structural Simulation of a MEMS
Micro-shutter
Abed M. Khaskia, David J. Power,
Mallett Technology, Laurel, MD 20707
James P. Loughlin
NASA/Goddard Space Flight Center, Greenbelt, MD 20771

Abstract
A finite element model has been created that simulates the ic actuation of a cobalt-iron covered,
µm thick, silicon nitride micro-shutter. The micro-shutter will be used as a transmissible filter in a
space-based Multi-object Spectrograph (MOS). A laminated tri-pole permanent is scanned across
an array of shutters. The applied ic force twists the shutter’s torsion hinge and actuates the shutter
from the closed, 0 degree, position, to the open, 90 degree position. A sequential analysis method was
selected. This method uses the interaction between the ic and structural fields and is plished
via the load vectors. The simulation results pared to experimental measurements of fabricated
micro-shutter devices.
Introduction
The James Webb Space Telescope (JWST) is being developed to determine the origin of galaxies. To
plish this, JWST needs a Multi-object Spectrograph (MOS) for Near Infrared (NIR) observations. In
order to reduce the background noise during observation, the MOS must have field selection capabilities.
The field selector will eliminate unwanted cosmic observations and leave only the object that the science
team wishes to observe. One method being considered for field selection is a transmissive
microelectromechanical (MEMS) micro-shutter array.
The micro-shutter array is created by etching a 100µm thick silicon wafer down to an embedded µm
silicon nitride membrane. The silicon nitride is etched away using a deep reactive ion etch (DRIE)
procedure. What remains is an 80µm x 90µm shutter with a 90µm x 3µm torsion hinge, Figure 1. The
overall dimension of the shutter pixel, including sidewalls, is 100µm x 100µm. Two more layers of
aluminum and iron cobalt providing the electric and ic prop