4:15 PM - 4:30 PM
[14p-423-12] Homogenization of Patterning Characteristics in an Exposure Field of Projection Lithography
Using a Gradient-Index Lens Array
Keywords:optical lithography, gradient-index lens array, projection exposure system
A simple and low-cost projection exposure system using a gradient-index lens array is under development for printing large patterns with widths of 20-100 μm. In the system, patterning performance in an exposure field was not uniform, and pattern widths distributed caused by individual optical property of each element lens. Although back-and-forth sub-scans in the lens array direction were added to the main scan in perpendicular to the lens array, the homogeneity was not sufficiently improved. In this research, the sub-scan length was extended, and sub-scan stages were returned at the outsides of the lens arrays used for the exposure. By this countermeasure, no places in the exposure field were exposed when the sub-scan stages were stopped for scan direction reversals, and all the patterns in the exposure field were printed under almost same exposure conditions. As a result, width homogeneity of printed 15-μm line-and-space patterns was vastly improved.<!--EndFragment-->