Nanomechanical mass sensor for monitoring deposition rates through confined apertures

A nanoelectromechanical mass sensor is used to characterize material deposition rates in stencil lithography. The material flux through micron size apertures is mapped with high spatial (below 1 µm) and deposition rate (below 10 µm/s) resolutions by displacing stencil apertures above the sensor. The sensor is based on a resonating metallic beam with submicron-size width and thickness. The beam is monolithically integrated with a CMOS readout and amplifier circuit to constitute a self-oscillator.