An optical workstation for characterization and modification of MEMS

An optical workstation consisting of a surface profiler, laser vibrometer and a high power pulsed laser has been constructed for mechanical testing of MEMS. Through a series of static and dynamic measurements, the performance of a device is determined in seconds. For these measurements the device is induced to move by either using mechanical, electrostatic or optical actuation methods. In the latter case this is achieved by directing high power light pulses onto a silicon surface. The same laser can also be used to trim and frequency tune resonant devices. The workstation has been designed to incorporate single devices, wafers and packaged devices so that devices may be characterised at any stage of processing. The speed and non-contact nature of this workstation makes it suitable for industrial metrology. A variety of MEMS have been characterised, examples of which are presented. The workstation has also proved to be an invaluable tool for determining the cause of device failure in prototype designs.