A Dynamic 3-D Surface Profilometer With Nanoscale Measurement Resolution and MHz Bandwidth for MEMS Characterization

Commercialization of microelectromechanical systems (MEMS) has made accurate dynamic characterization a major challenge in design and fabrication. In view of this need, a dynamic 3-D surface profilometer involving white light interferometric scanning principle with a stroboscopic LED light source was developed. The developed instrument was applied to a microcantilever beam used in atomic force microscopy (AFM) to analyze its full-field resonant vibratory behavior. The first five resonant vibration modes were fully characterized with vertical measurement accuracy of 3-5 nm and vertical measurement in the range of tens of micrometers. The experimental results were consistent with the outcomes of the theoretical simulation by ANSYS. Using stroboscopic illumination and white light vertical scanning techniques, the developed static and dynamic 3D nanoscale surface profilometry of MEMS devices can achieve measurement range of tens of micrometers and dynamic bandwidth of up to 1-MHz resonance frequency.