Double-sided structured mask for sub-micron resolution proximity i-line mask-aligner lithography

Area of Science:

• Optics and Photonics
• Nanofabrication
• Materials Science

Background:

• Mask-aligner lithography achieves sub-micrometer resolution using non-contact methods.
• Conventional techniques often require separate spectral filters and polarizers for linearly polarized light.
• Existing methods limit polarization control and flexibility during high-resolution patterning.

Purpose of the Study:

• To propose and demonstrate a novel mask design for mask-aligner lithography.
• To enable the printing of high-resolution gratings with controlled polarization.
• To enhance the flexibility and efficiency of lithographic processes.

Main Methods:

• Integration of a wire-grid polarizer (WGP) on the top of a photomask.
• Incorporation of a diffractive element on the bottom of the photomask.
• Utilization of a classical mask-aligner in proximity exposure mode with unpolarized light.

Main Results:

• Successful printing of a 350 nm period grating.
• Demonstration of local linear polarization of an unpolarized incident beam using the WGP.
• Achieved capability to print structures with different orientations within a single exposure.

Conclusions:

• The proposed mask design offers a versatile solution for high-resolution lithography.
• This approach allows for flexible control over polarization orientation on a single mask.
• The method enhances the efficiency of fabricating complex nanostructures.