Monitoring apparatus and method particularly useful in photolithographically processing substrates

An apparatus for processing substrates according to a predetermined photolithography process, comprising:

• a loading station in which the substrates are loaded from at least one first cassette;
• a coating station in which the substrates are coated with a photoresist material;
• an exposing station in which the photoresist coating is exposed to light through a mask having a predetermined pattern to produce a latent image of the mask on the photoresist coating;
• a developing station in which the latent image is developed;
• an unloading station in which the substrates are unloaded;
• and
• a monitoring station for monitoring the substrates with respect to predetermined parameters of said photolithography process and before being unloaded in at least one second cassette at said unloading station, said monitoring station comprising:
• a supporting plate for receiving substrates to be inspected;
• a sealed enclosure having a transparent window aligned with and facing said supporting plate;
• said supporting plate being external to said sealed enclosure and spaced from said window thereof;
• an optical monitoring system with said sealed enclosure for inspecting substrates on said supporting plate via said transparent window;
• and
• a light source for illuminating the substrates via said optical monitoring system.