The majority of photoresists is almost exclusively soluble in organic solvents like e.g. PGMEA (propylene glycol methyl acetate, German: PMA). But there are exceptions: cathode ray tube screens for example were in the past manufactured with casein and ammonium dichromate as crosslinking agent. Due to the toxic and carcinogenic properties of dichromate, this process is however no longer performed. In the manufacture of solar cells, preferably aqueous coatings on gelatine basis are used today. Layers are after exposure treated with H2O2 and developed with water. Allresist has developed similar negative resists within the framework of a research project. Many possible applications exist for water-based resists, since they are very well suited for multi-layer systems in combination with normal photoresists and also suitable for organic solvent-sensitive films. Photoresist patterns are in this case produced on the gelatine layer and structures are then removed in a water bath. By these means, patterned resist films are generated.
Overview Photoresists- Negative