Reduction of buried microstructure diffraction in fabricating curved microstructure by multiple exposure method.

Area of Science:

• Optical Engineering
• Microfabrication
• Nanotechnology

Background:

• Digital micromirror device (DMD)-based digital lithography is used for microfabrication.
• Buried microstructures in photoresist cause diffraction, reducing fabrication fidelity for curved designs.

Purpose of the Study:

• To demonstrate a multiple exposure method to reduce diffraction effects from buried microstructures.
• To improve fabrication fidelity in DMD-based digital lithography for curved microstructures.

Main Methods:

• Decomposing high-space-frequency curved microstructures into multiple low-space-frequency sub-microstructures.
• Successively exposing corresponding digital masks at the same substrate position.
• Utilizing the Finite-Difference Time-Domain (FDTD) method to analyze diffraction.

Main Results:

• The multiple exposure method effectively reduced superimposed diffraction effects on lithography patterns.
• Experimental results confirmed a significant reduction in buried microstructure diffraction.
• FDTD analysis provided insights into factors influencing diffraction.

Conclusions:

• The multiple exposure method enhances fabrication fidelity in DMD-based digital lithography.
• This technique is particularly promising for fabricating deep and curved microstructures.
• The study offers a viable solution for overcoming diffraction limitations in microfabrication.