Laser beam shape effect in optical control of the μ-fluidic channel depth employing scatterometry

In this work system of the μ-fluidic devices of different depths was fabricated in fused quartz substrates employing standard contact optical lithography and plasma chemical etching in CF4/O2 feedstock gas mixture. To evaluate linear dimensions (depth and microrelief) of the fabricated structures we have employed monochromatic light diffraction efficiency measurements applying different wavelength lasers: 405, 532, 632.8 nm and theoretical simulations performed with GSolver software—scatterometry technique (SC). Additionally, depth and profile of the etched structures was evaluated employing roughness meter (RM) and scanning electron microscope (SEM). We have analyzed feasibility of the method when diameter of the laser beam exceeds the width of the periodic structure and laser beam intensity distribution coefficients should be taken into account.