Positive resist

Foto resist. A polymer lacquer which is almost unsoluable after hardening. However the lacquer contains an additive which is sensitive to electromagnetic radiation (visible or UV). The additive is designated foto initiator. Radiation causes conversion of the foto initiator to carbonic acid H2CO3 and because of this modification the lacquer will be easily soluable by lyes (alcaline solcents). After irradiation and the development process by a dye the areas which have been exposed to radiation will be removed, the areas non irradiated remain.