A photoresist 10 is exposed to light from behind a substrate by using as photomask a wiring electrodes 2 and 4 and a switching element 8 which are individually composed of an opaque member, whereby a passivation layer 9 for the switching element 8 is patterned. By virtue of this method, a photomask becomes...http://www.google.de/patents/US5477355?utm_source=gb-gplus-sharePatent US5477355 - Process for producing the passivation layer of an active matrix substrate by back exposure
