Edge smoothness enhancement in DMD scanning lithography system based on a wobulation technique

Area of Science:

• Microfabrication
• Optical Engineering
• Materials Science

Background:

• Digital micro-mirror device (DMD) scanning lithography faces transverse resolution limits due to micro-mirror size and low projection magnification.
• These limitations result in a noticeable saw-tooth edge pattern in lithography, impacting pattern quality except in the scanning direction.

Purpose of the Study:

• To propose and demonstrate an optimized sub-pattern construction method for smoothing the saw-tooth edge in DMD scanning lithography.
• To investigate the effectiveness of combining wobulation techniques with continuous scanning lithography.

Main Methods:

• Implemented wobulation techniques within a DMD scanning lithography system.
• Conducted lithography experiments to evaluate edge smoothness after applying the proposed method.

Main Results:

• The saw-tooth edge size was reduced to approximately 0.5 pixels after 1/2 pixel dislocation superposition exposure.
• Further reduction of the saw-tooth edge to less than 0.1 pixels was achieved with 1/4 pixel dislocation superposition exposure.
• Demonstrated significant improvement in the edge smoothness of lithography patterns.

Conclusions:

• The proposed method, combining wobulation and continuous scanning lithography, effectively smooths the saw-tooth edge.
• This technique enhances the resolution and quality of patterns produced by DMD scanning lithography.
• The findings validate the practical application of wobulation for improving microfabrication processes.