A Flexible PCB Based Out of Plane Bimorph MEMS Thermal Actuator

The fabrication of micro-devices and MEMS using flexible polyimide substrate and leveraging PCB manufacturing process is a new microfabrication trend in recent years. It has some benefits compared to conventional micromachining processes, such as low cost, and minimal cleanroom requirement. Thermal actuators are one of main types of actuators in MEMS devices and are used in many applications. For out of plane movement, bimorph thermal actuators are often used. FPCB substrates employing metal-polymer layers can be configured to form bimorph actuator. In this work, we design and fabricate a U-shaped bimorph thermal actuator based on FPCB. Simulations are performed to investigate the stationery and time dependent performance. The fabricated actuator is tested using a 0.5 A driving current, and the actuator measured 11 μm displacement. The spring constant is measured to be 4.7 N/m.