Electron-beam lithography for polymer bioMEMS with submicron features.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Flexible, thin-film structures require advanced fabrication techniques for high resolution.
• Poly(chloro-p-xylylene) (Parylene C) is a biocompatible polymer suitable for encapsulation.
• Prior methods had limitations in achieving submicron feature sizes.

Purpose of the Study:

• To develop a submicron fabrication method for flexible, thin-film structures encapsulated in Parylene C.
• To improve feature size and resolution by an order of magnitude.
• To demonstrate the fabrication of functional microelectronic components and a neural probe prototype.

Main Methods:

• Adapted electron beam lithography for vapor-deposited Parylene C-coated substrates.
• Fabricated encapsulated metal structures: conducting traces, serpentine resistors, and nano-patterned electrodes.
• Characterized electrical and mechanical properties, including performance under mechanical stress.

Main Results:

• Achieved critical dimensions as small as 250 nm, an order of magnitude improvement.
• Demonstrated robust electrical and mechanical performance of fabricated structures, even under flexion and torsion.
• Fabricated a Parylene-based neural probe prototype with 32 recording sites, achieving high electrode density.

Conclusions:

• The developed electron beam lithography process enables high-resolution submicron fabrication on Parylene C.
• The technique is suitable for creating robust, flexible microelectronic devices and advanced neural probes.
• This method significantly advances the capabilities for fabricating polymer-based microdevices.