Metal-armouring for shock protection of MEMS

• Highly compliant MEMS suspension systems are fabricated from silicon using DRIE.
• Metal-armouring in the form of solder is used to protect the silicon suspension systems from shock-induced damage.
• The MEMS suspension systems, both armoured and unarmoured, are shock tested in a drop-test rig at accelerations levels up to 6000 × g.
• Plastic deformation of the solder absorbs ∼90% of the collision kinetic energy.
• The solder–armour proved to double the robustness of the MEMS suspension systems.

This paper demonstrates a novel concept for the shock protection of MEMS suspensions: solder is incorporated within the sidewalls of the suspension to produce protective metal armouring. This provides solder–solder contact at the extremes of the suspension travel, greatly increasing the shock resistance. Model suspension systems were fabricated using deep reactive ion etching (DRIE) and shock tested in a drop-test rig at acceleration levels up to 6000 × g. The solder armour proved to absorb ∼90% of the collision kinetic energy and double the shock resistance of the MEMS suspension.