Two in One: Light as a Tool for 3D Printing and Erasing at the Microscale

Area of Science:

• Materials Science
• Additive Manufacturing
• Photochemistry

Background:

• High-resolution selective removal of 3D-printed structures is a significant challenge in 3D laser lithography.
• Existing methods often lack the precision required for complex microfabrication tasks.

Purpose of the Study:

• To introduce a novel photoresist enabling both additive fabrication and selective cleavage of 3D microstructures.
• To demonstrate spatially controlled removal of printed features using distinct laser wavelengths.

Main Methods:

• Development of a photoresist based on a difunctional acrylate cross-linker with a photolabile o-nitrobenzyl ether group.
• 3D microstructure fabrication via two-photon absorption polymerization using 900 nm laser light and Ivocerin photoinitiator.
• Selective resist cleavage via two-photon absorption using 700 nm laser light to photocleave the o-nitrobenzyl moiety.

Main Results:

• Successful additive fabrication of 3D microstructures with high resolution.
• Demonstration of selective, spatially controlled removal of printed resist sections.
• Complete elimination of a single wire bond from an array, validating on-demand structure modification.
• Imaging of fabricated and erased features using scanning electron microscopy (SEM) and laser scanning microscopy (LSM).

Conclusions:

• The novel photoresist facilitates dual-wavelength, two-photon absorption-based 3D laser lithography for both fabrication and selective removal.
• This technology offers on-demand control over 3D microstructures, opening possibilities for advanced applications in microfabrication.