CAR 44 on copper
If negative photoresist CAR 44 (AR-N 4400) is directly used on copper or copper-containing substrates, the following points must be observed.
Fabrication of vertical flanks with CAR 44
AR-N 4400-50 was investigated at the TU Braunschweig with particular regard to the fabrication of well-defined resist architectures with vertical flanks.
Surface imaging resist system SX AR-N 7100 – silylable photoresist
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.
Alkali-stable positive resist obtained after treatment with HMDS
A large variety of applications include a wet-chemical etching step which very often involves highly alkaline etching baths.
Adaptable two-layer resist AR-BR 5460 for variable lift-off structures
Bottom resist AR-BR 5460 has already been used for a decade in combination with positive (e.g. AR-P 3510) or negative resists (e.g. AR-N 4340) for a large variety of lift-off applications.
Structuring of polyphthalaldehydes with photolithography
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.
Ethanol and toluene-resistant photoresist AR-U 4060
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.
Two-layer photoresist system for water-sensitive substrates
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.
Dose-dependent structure size with negative resists
The desired structure size also largely depends on the exposure dose used. In the case of overexposure, structures begin to widen which is particularly pronounced during laser exposure.
Generation of undercut structures with negative resists
With laser direct exposure, a slight undercut of the structures can be generated: The upper part of the layer is more strongly irradiated due to the absorption of the resist and consequently more intensely crosslinked.