Two-layer resist system for hydrofluoric acid etching
Hydrofluoric acid etchings, even those in highly concentrated acids (48%), are technologically used despite the high risk involved with HF applications.
Hydrofluoric acid etchings, even those in highly concentrated acids (48%), are technologically used despite the high risk involved with HF applications.
Protective coatings AR-PC 503 and 504 are able to withstand the presence of 40%, 85°C warm KOH for several hours. The polymer PMMA is not attacked under these conditions. These resists can consequently be used to protect front and back surface of wafers during deep silicon etching.
Most novolac-based photoresists are characterized by high etch stability in the presence of acids (except in highly concentrated oxidizing acids or in concentrated hydrofluoric acid
New aqueous-alkali soluble polymers may even outperform novolacs in certain features. Standard novolacs generally melt in a range between 115–130°C. The thicker the resist film, the higher is the impact of this feature on the resist structure.
Solvents are the main component of all resists, with solvent contents ranging from 50% (thick resists) to up to 99% (spray resists).
Aqueous-alkaline developers are subjected to ageing, due to an uptake of CO 2 from the air. Buffered aqueous-alkaline developers ( AR 300-26, -35 ) are more stable in this respect than developers of the AR 300-40 -series containing TMAH.
First experiments with our SX AR-P 5000/82.7 using e-beam lithography clearly demonstrated that this resist can easily be patterned which offers the possibility to generate nanostructures which are thermally stable up to 350 °C.
A process-stable, sufficiently sensitive e-beam resist with a resolution of about 30 nm is urgently needed to accelerate the progress in electron beam lithography.
Two procedures are principally possible to manufacture e.g. conducting paths: 1. Etching technique: A thin metal film (e.g. aluminium) is deposited on a wafer (evaporation or sputtering)
Photoresists are particularly employed in microelectronics and in microsystems technology to generate µm- and sub-µm structures.