Quasi-Random Gratings Enabled by Wrinkled Photoresist Surfaces on a Rigid Substrate

Area of Science:

• Materials Science
• Nanotechnology
• Surface Engineering

Background:

• Micro- and nanoscale surface wrinkling is typically studied in soft materials like polydimethylsiloxane.
• Existing methods often rely on thermal stresses or tensile prestrains to induce wrinkling.
• A need exists for new wrinkling regimes applicable to rigid substrates.

Purpose of the Study:

• To introduce a novel wrinkling regime on photoresist layers atop rigid substrates.
• To achieve controllable fabrication of micro- and nanoscale wrinkles with specific wavelengths.
• To demonstrate the utility of these wrinkled surfaces for creating advanced materials.

Main Methods:

• Utilizing bending deformation combined with fluorine-based plasma treatment on photoresist layers.
• Incorporating micropatterns on photoresists with standard UV exposure to achieve ordered wrinkles.
• Applying the technique to commercially available photoresists.

Main Results:

• Successfully created wrinkles with characteristic wavelengths less than 1 μm.
• Demonstrated the ability to realize ordered wrinkles through micropatterning.
• Showcased the application of wrinkled patterns for fabricating high-aspect-ratio silicon gratings and large-area silicon dioxide membranes.

Conclusions:

• A new, controllable wrinkling regime on rigid substrates using photoresists has been established.
• This technique expands the range of materials for creating wrinkled surfaces.
• Provides a versatile platform for fabricating wrinkle-based devices and nanostructures.