The basic principle of laser ablation is that laser irradiation of a certain wavelength introduces so much energy into the resist material which is modified for ablation that the resist polymer is destroyed and then vaporizes as low molecular weight fragments.
The basic idea behind dyed resists developed within the scope of the Photoenco project (June 2016 – May 2019) was that dyes are mixed into the polymer matrix of the resist which then either change their colour or become colourless upon irradiation.
Photoresists can also be used to incorporate fluorescent dyes. Particularly negative-tone photoresists are of interest in this regard, since the use of selected fluorescent dyes allows defining an adjustable emission in variable wavelength ranges. Resist layers with violet, blue, yellow, orange, or red fluorescence were produced by embedding the respective dyes into the negative-working Atlas 46 S resist.
The principle of chemical amplification could successfully be transferred to PMMA polymers. The new special resist SX AR-N 4810/1 is a chemically amplified photoresist based on PMMA that can be developed anhydrously with organic solvents – a crucial property in the case of moisture-sensitive substrates.
The new development Atlas 46 could also be successfully used for nanoimprinting (University of Wuppertal, working group of Prof. Scheer). In a first step, nanostructures were produced with the negative-working resist
The negative photoresist experimental sample SX AR-N 7100 is a surface imaging and dry developable system. With this system, structures can be transferred into thick resist layers by means of plasma etching.
A large variety of applications include a wet-chemical etching step which very often involves highly alkaline etching baths.
PPA layers are sensitive to light and can thus be structured directly by photolithography. Irradiation with light of wavelengths < 300 nm (Hg vapour lamp) results in a cleavage of the polymer chains and the formation of volatile components that partly begin to evaporate even at room temperature.
Structures of the image reversal resist AR-U 4060 show an increased resistance against organic solvents after flood exposure with subsequent tempering. Ethanol and toluene attack normal positive resist layers quickly, which are consequently dissolved in short time.
If contact of a substrate with water must be avoided during the patterning process, a two-component photoresist system composed of PMMA resist (bottom layer) and photoresist (top layer) offers an alternative to SX AR-N 4810/1.