Apparatus for aligning mask and wafer used in semiconductor circuit element fabrication
 An alignment apparatus for aligning a semiconductor wafer with an optical mask containing a circuit pattern to be exposed onto the wafer in the fabrication of semiconductor devices by a proximity exposure apparatus. The alignment apparatus includes light beam radiating means for radiating a first and second light beams which are imaged at positions separated by a given gap in a direction substantially perpendicular to two flat sheets, first and second detecting means for respectively detecting the imaging condition of the first and second light beams at the flat sheets, means for relatively moving the light beam radiating means and the flat sheets, and means for discriminating the order of generation of signals from the first and second detecting means, whereby the value of each gap between the selected areas of the two flat sheets at a plurality of places is detected with a high degree of accuracy without changing the gap between the flat sheets thereby making it possible to correct the parallelism, inclination, etc., of the flat sheets. 
Nippon Kogaku K.K.
G
G03F
inventional
Akikazu Kinya Junji Hisao
Tanimoto Kato Hazama Izawa