Measure structure of MEMS

Measuring the success of fabrication and design in manufacturing microscopic structures such as micro-electronic machine systems (also known as MEMS), is an instrumental benefit to the development of new design and micromachining or etching, ion beam, or laser-cutting MEMS fabrication processes.

Measuring MEMS function

In one experiment1 surface measurements using 3D optical profilometry measured diaphragm deflection in fluid gate microvalve arrays. Using a vertical scanning interferometer, deflection of closing plates in micro-valve arrays was measured on live, electrically activated MEMS arrays. By providing a three dimensional map of the activated MEMS, deflection was seen to be essentially 2-dimensional. The measurements helped to prove the effectiveness of the design concept, and measure the success of the valve in fluid control. By varying differential pressure and obtaining a new non-contact measurement of the deflection of the valve diaphragm at each pressure variable, the relative shape of the diaphragm could be known at varying flow rates.

3D optical surface profilers are useful in measurements of deformable mirrors, electrostatic actuators, adaptive optics and MEMS fluid or gas flow control. Measurements can be made at various steps in the process, including alterations due to plasma deposition, heat-transfer phenomena and so on. Micromachined devices with engineered surfaces, deformable mirrors and membrane active micromirrors are also candidates for successful structure characterization. Indeed, MicroXam is programmable to measure micromechanical arrays automatically, or to create 3D large-area stitched profiles of contiguous surface material.

Non-contact profiling of MEMS

Measure the response of MEMS to mechanical processes or electric fields — electro-mechanical means are often used for activating MEMS. As the National Physical Laboratory (UK) has reported2, "the optical interferometric system is particularly suitable for on-line [in-line] inspection." Measurements in situ of activated MEMS provides live feedback of the process and success of designs, which allows further technological development of microstructures and micromachined arrays.