Development of a wide-width raster scanning optical system for high-resolution ultraviolet laser direct micro-patterning

We developed F-theta raster scanning optics for high-resolution ultraviolet (UV) beam direct micro-patterning, capable of machining on a 300-mm wide image with a confined beam spot of less than 20 μm, a 13.5% spot size. To achieve the imaging performance with resolution, F-theta optics based on synthetic silica glass were designed using a high-power laser light source with a wavelength of 355 nm. In addition, to improve the difficulty of optical alignment in conventional systems and the scan linearity between the scan angle and exposing position, F-theta scanning optics were designed to contain two lenses with a rotationally asymmetric high-order polynomial surface. The designed optical system showed a performance of 20 ± 2 μm at the full width of a 1/e² maximum intensity value through a 0.8 mm focal depth. The scanning linearity error and root-mean-square (RMS) wavefront error were designed to be less than 0.2% and 0.05 λ, respectively.