Improved projection-matrix-exposure using a liquid crystal display panel for printing smooth arbitrary patterns without reticles
Projection-matrix-exposure using a liquid crystal display (LCD) panel in place of a reticle is convenient for printing various patterns easily. However, since there are black matrix lines formed by opaque cell boundaries, undesirable notch defects or extrusion defects are printed. For this reason, two approaches are tried here for reducing the defects. In the first approach, a tapered optical fiber bundle is put contacting to the LCD panel. Because the opaque cell boundaries are made vague, smooth patterns with a width of 3.5 ?m are printed successfully. In the second approach, a cell-window reshaping aperture plate was attached to the LCD panel. Stitching the circular exposure elements, smooth patterns with a width of about 8 ?m are obtained successfully. Thus, disadvantageous pattern width fluctuation ratios are improved to less than half the conventional value.
liquid crystal display tapered optical fiber bundle cell-window reshaping aperture optical projection lithography matrix exposure