EVGNEWS Issue 4 2016


Nanoimprint Lithography: Innovative patterning processes for bio- and medical devices

Hot Embossing
Replication of microfluidic patterns into polymer materials and glass

With hot embossing, a polymer sheet or spin-on-polymer is heated above its glass transition temperature, which transforms the material into a viscous state. A stamp containing the negative copy of the structures is then pressed into the polymer with sufficient force to conformally mold the polymer. De-embossing is done after cooling the substrate below a certain temperature where the material retains its shape when removing the stamp. During hot-embossing, the structure is transferred by displacement of the viscous material.

Key features:

  • Simultaneous replication of micro- and nanostructures
  • Imprinting into bulk polymer materials or glass
  • Suitable for spin-on thermoplastics
  • Low residual stress
  • High replication accuracy down to 50 nm
  • High aspect ratio features


UV-Nanoimprint Lithography (UV-NIL)

Nanostructured surfaces with the highest resolution

UV-NIL refers to a technique where a transparent stamp is pressed into a photo-curable resist and crosslinked by UV light while still in contact. In biotechnology applications, the resist is usually coated onto silicon or glass substrates. Unlike hot-embossing, the UV-NIL stamp is brought in contact with the resist using minimum force to conformally join the stamp and substrate.

Key features:

  • Robust and field-proven proprietary SmartNILTM technology
  • Volume-proven imprinting technology with superior replication fidelity and resolution down to 20 nm
  • Room-temperature process based on UV-curable resist
  • Imprinted UV-NIL resist directly suitable as functional layer
  • High-uniform residual layers for optimum pattern transfer by etching


µ-contact Printing (µ-CP)
Transfer of biomolecules onto substrates in a distinct pattern

In µ-CP, a structured elastic stamp is used to transfer materials such as biomolecules onto a substrate. The structure of the stamp is thereby replicated as a molecular layer pattern on the substrate. This technique is applicable on all common surfaces, such as silicon, glass or polymers with micrometer and nanometer resolution, and offers new possibilities for the surface functionalization of biotechnology devices. 

Key features:

  • Local modification of surface chemistry
  • Precise placement of capture molecules for bio-sensing applications
  • Applicable on all common surfaces
  • Micrometer and nanometer resolution


200 µm wide microfluidic channels
Courtesy of National Research Council Canada

10 µm pillar arrays with high aspect ratios (7:1)
Courtesy of National Research Council Canada

100 nm grating with residual layer <10 nm imprinted into 90 nm height resist on silicon substrate

350 nm photonic crystal

Biological sample interacting with directly imprinted functional array
Courtesy of FH Wels

Click to read our article "Processes for Next-Gen Biotech Devices"