Coordinate measurement of micro groove on MEMS device by optically controlled microprobe

Abstract

Recently, ultra-high accuracy coordinate measuring m achine (Nano-CMM) is demanded for inspecting 3D shapes of micro components. The most important element to achieve the Nano-CMM is the probe for sensing surfaces of 3D components. In this study, laser trapping probe, which is the micro-sphere trapped in air by optical radiation pressures, is proposed as a novel probe. In this paper, micro-groove structure on micro electromechanical system (MEMS) device is measured by using laser trapping probe with circular motion, which is improved to have same sensing property by use of the element of radial polarization. The probe has a diameter of 8 μm while conventional micro probes have a diameter of several tens of μm. The small probe makes it possible to measure narrow space of 50 μm. Moreover, the probe enables to measure specimen regardless of the approaching direction. This shows the potential that laser trapping probe enables to measure any micro structure with same manner. Although there are some conjectures to resolve, it seems that the laser trapping probe is validity as a probe for Nano-CMM.