Generation of trapezoidal illumination for the step-and-scan lithographic system

Abstract

To meet the uniform dose exposure in optical lithography, it is desirable to get uniform illumination and trapezoidal illumination in the scanning direction on the wafer for the step-and-scan lithographic system. A design strategy for trapezoidal illumination is proposed which offers both high uniformity illumination and fixed integral energy of trapezoidal illumination in a different illumination pattern. The strategy describes a light uniform device which contains a microlens array, a microcylindrical array, and a Fourier lens and produces trapezoidal illumination directly at the scanning slit. Compared with the conventional method to obtain the trapezoidal illumination, the strategy in this paper reduces the difficulty of assembly and has the advantage of simplicity and directness without blocking energy. This method utilizes energy of the lithographic system more effectively, and it improves the throughput of the lithography. The simulation results show that this method not only maintains the uniformity of trapezoidal illumination but also improves the energy utilization.

3D Printing of a PDMS Cylindrical Microlens Array with 100% Fill-Factor

“…Cylindrical MLAs (CMLAs), which act as typical noncircular MLAs, play a vital role in some applications including single-photon avalanche diodes (SPADs), 11 seam concealment in tiled displays, 12 Shack−Hartmann sensors, 13 3D imaging, 14 organic light-emitting diodes (OLEDs), 15,16 and trapezoidal illumination. 17 However, the fabrication of CMLAs still faces great challenges because there are differences in scale in the length direction and the width direction. So far, several fabrication strategies for CMLAs have been developed, such as femtosecond laser one-step direct-writing, 18 roll-to-roll ultraviolet embossing, 19 an ultrashort pulsed laser and CO 2 laser combining method, 20 and the pinning effect and UV curing.…”

“…The representative manufacturing strategies mainly include the surface-tension-effect-assisted technology, photolithography-assisted technology, mechanical manufacturing technology, graphic-transfer technology, and chemical synthesis. − Most fabricated MLAs have a center symmetrical footprint. Cylindrical MLAs (CMLAs), which act as typical noncircular MLAs, play a vital role in some applications including single-photon avalanche diodes (SPADs), seam concealment in tiled displays, Shack–Hartmann sensors, 3D imaging, organic light-emitting diodes (OLEDs), , and trapezoidal illumination . However, the fabrication of CMLAs still faces great challenges because there are differences in scale in the length direction and the width direction.…”