Hot embossing is very similar to thermal nanoimprint lithography. It is the process of structuring polymer films or pieces, by pressing a stamp into the polymer while it is heated above its glass transition temperature.
In nanoimprint lithography, you press a stamp into a polymer layer and leave behind a relief of the stamp topology. In hot embossing, you press a stamp into a polymer surface and leave behind a relief of the stamp topology. So what is actually the difference?
Hot embossing versus nanoimprint lithography
The difference between hot embossing and nanoimprint lithography is that when you perform hot embossing, the polymer is much thicker than the height of the stamp structures. The relief is only a perturbation of the total polymer thickness.
In nanoimprint lithography, the thickness of the polymer layer is comparable with the stamp structure height, and the relief might thin down the polymer thickness to a small percentage of the initial thickness under the protrusions.
Squeezing polymer into a nanometer thin layer takes much more force and mechanical work compared to perturbation of the surface of a thick polymer. The latter process is almost instantaneous, and the polymer flow is almost without resistance. A nanoimprint process takes longer time, and it takes lots of force to drive the polymer flow.
Furthermore, hot embossing is less prone to defects than nanoimprint lithography and it is not limited to nano or microstructures. Embossing plastic parts by pressing a heated stamp with macro scale features into the plastic is a standard procedure.
In the world of micro and nanotechnology, hot embossing is often used for large area polymer devices with micro and nanostructures. Examples include microfluidic devices potentially with multiple length scales and structure levels in a single fabrication step, Lab-on-a-chip components, microlenses, anti-reflective polymer films, and non-stick polymer films.
Typical materials used for the process are PMMA, COP, COC and PC.
Please contact us if you would like to know more.