Hot Embossing Lithography

Hot Embossing Lithography (HEL) is a Nano Imprint Lithography (NIL) method using controlled temperature and pressure during the imprint process.

It permits to replicate patterns which dimensions can be as small as few tens or hundreds of nanometers.

Unless the substrate is itself a thermoplastic material, such as polycarbonate for instance, it is coated with the hot embossing material (thermoplastic resist or polymer) using spin coater.

HEL Process

The stamp is aligned to the substrate. The accuracy requirement varies with the application. For some single or first level application, there is no need for alignment: a rough pre-alignment can be sufficient.

To transfer the stamp patterns into the material, the stamp and the substrate are heated above the glass transition temperature of the resist material to soften it and to minimize the force required for the material to flow into the stamp cavities.

After the pattern is imprinted into the material (pattern transfer), the temperature of the substrate and the stamp return below the Glass Transition Temperature (Tg) of the material, the stamp is separated from the imprinted material layer which retains the features transferred from the stamp patterns.


NIL Technology

Low cost production solutions of nanostructures are in development that may be the driving forces of Semiconductor, MOEMS and optoelectronics technology tomorrow. In particular, Nanoimprint lithography (NIL) and its variations have been developed as a cost-effective alternative to high-resolution e-beam lithography to print sub-20 nm geometries.

Imprinting is based on the principle of mechanically pressing thin polymer film with a stamp containing the nanopattern, in a thermo-mechanical or UV curing process. The patterned polymer can act as a final device, e.g. lense for imaging sensors, micro fluidic chip, biomedical array etc. It can also be used as a high resolution mask for subsequent steps of the process.

Imprinting is a straightforward lithography technology. There are three basic process steps:

  • Align the stamp with the substrate which has been pre-coated with the imprinting material
  • Press the stamp into the imprinting material to transfer the pattern
    written on the stamp surface
  • Separate the stamp from the imprinting material

We can describe three imprinting or embossing techniques: Hot Embossing Lithography (HEL) using thermal plastic material, UV-NIL using a liquid resist which is then cured with UV light after molding and Soft Lithography which transfers ink previously applied to a soft stamp onto a substrate using a stamping method.

NaPa Library of Processes

The NaPa library is  a collection of 27 processes, recipes, references performed in the field of nanopatterning. It aims to enable researchers and engineers to choose from different processes depending on the specific challenges of a new application.


 About NaPANIL

NaPANIL is a NMP thematic priority European-funded Framework 7 Large-Scale Project, bringing together 18 partners from: industry, academia, and private institutes, to achieve ambitious goals.
Click here to learn more about the European NaPANIL Project!

NIL Papers





NaPa "Library of Processes"

January 2010

This FREE 152 pages book gives all directions needed to chose and apply an alternative nano-patterning technique: it is a must read for all! 


Access to NaPANIL's website:
=> Please click on Direct Link to download it!

UV nanoimprint lithography process optimization for electron device manufacturing on nanosized scale

November 2008

Imprint specific process parameters like the residual layer thickness and the etch resistance of the UV polymers for the substrate etch process have to be optimized to introduce UV nanoimprint lithography (UV NIL) as a high-resolution, low-cost patterning technique...

Access to IISB's Library:

=> Please click on Begin Search, type "schmitt" as person and "nanoimprint" as keyword.

=> Then you will access to all latest papers!

UV nanoimprint lithography process optimization for electron device manufacturing on nanosized scale

September 2008

It's a poster


UV nanoimprinting lithography using nanostructured quartz molds with antisticking functionalization

February 2008

In this paper, we report the results obtained by the application of the SET FC150 equipment for UV-NIL...


Partnerships in NIL