Homework #5
Assigned: Sep. 21st, 2010
Due: Sep. 28th, 2010
Points: 50

• 50 points
  You have 50 mm² area on a chip. The thickness of the structural layer that you can anchor, etch away, or suspend is 25 um. Design a suspension that gives as much static displacement as possible along an in-plane axis under 1 g (=9.81 m/s²) acceleration load along the same axis. The following conditions must be obeyed.
  • Use the following material properties: Y = Young's modulus; 159 GPa, nu = Poisson's ratio = 0.25; rho = material density = 2300 kg/m³
  • The stiffness of the suspension in the in-plane cross-axis must be 50 times larger than that in the acceleration axis.
  • Anchor pads must be larger than 100 um by 100 um squares.
  • In-plane beam width must be larger than 5 um, and the beam length cannot be more than 600 um.
  • Smallest in-plane gap should be larger than 4 um.
  Please submit the full details of your design with a neat sketch and properly marked dimensions. Provide the analysis details that you used to arrive at your design.