λ/30 inorganic features achieved by multi-photon 3D lithography

Area of Science:

• Materials Science
• Nanotechnology
• Photolithography

Background:

• Hydrogen silsesquioxane (HSQ) is an inorganic photoresist suitable for high-resolution patterning.
• Conventional patterning methods using EUV and electron beams face limitations for 3D nanoscale feature fabrication with infrared light.

Purpose of the Study:

• To demonstrate the fabrication of 3D nanoscale inorganic features using femtosecond laser direct writing (FsLDW) of HSQ.
• To achieve super-diffraction limit resolution for HSQ patterning using infrared light.

Main Methods:

• Femtosecond laser direct writing (FsLDW) utilizing a multi-photon absorption process.
• Patterning of hydrogen silsesquioxane (HSQ) with a 780 nm femtosecond laser.

Main Results:

• Achieved a feature size of 26 nm, representing a resolution of λ/30 (super-diffraction limit photolithography).
• Fabricated HSQ microstructures with nanoscale resolution, smooth surfaces, and thermal stability up to 600°C.
• Demonstrated the construction of structural color and Fresnel lenses with desirable optical properties and resistance.

Conclusions:

• FsLDW of HSQ offers a flexible method for creating inorganic features with nanoscale resolution.
• The fabricated microstructures exhibit excellent thermal and chemical resistance.
• This technique holds promise for fabricating advanced micro-nano devices requiring high resolution and material robustness.