Shape Transformation Photolithography: Self-Assembled Arrays of Suspended MEMS Structures from Patterned Polymer...

Area of Science:

• Materials Science
• Nanotechnology
• Mechanical Engineering

Background:

• Traditional methods for suspended micromechanical structures risk damage from capillary forces during solvent removal.
• Existing capillary force-directed fabrication methods have limitations in manufacturing speed and pattern flexibility.

Purpose of the Study:

• To introduce Shape Transformation Photolithography (STP) for fabricating arbitrarily patterned arrays of suspended fibers.
• To demonstrate a method capable of high fabrication rates for suspended fiber structures.

Main Methods:

• STP involves prepatterning holes in a polymer nanofilm on a micropillar array.
• Heating the film above its glass transition temperature causes holes to expand via dewetting.
• Capillary forces then thin polymer channels, forming suspended fibers.

Main Results:

• Prepatterning ensures simultaneous fiber formation with uniform diameters by overcoming nucleation energy barriers.
• Arrays of fibers and lattice networks were successfully fabricated from dyed polystyrene films using nanosecond laser pulses.
• The exposure threshold for hole formation is compatible with existing wafer-stepping projection printers.

Conclusions:

• STP offers a versatile and potentially high-throughput method for creating complex suspended fiber structures.
• The technique overcomes limitations of previous fabrication methods, enabling arbitrary patterning.
• STP shows promise for integration into industrial manufacturing processes for microdevices.