| 摘要 |
PURPOSE:To improve the position aligning accuracy of a reticle and a wafer, i.e. the overlapping accuracy in light transfer by setting the specified relationship between the intersecting angle formed by two reflecting surfaces and the angle formed by an incident light beam and an emitting light beam. CONSTITUTION:A pentagonal prism has a reflecting surface 31 which receives and reflects an incident beam and a reflecting surface 32 which receives the reflected light beam and reflects the beam again. The reflecting surface 32 guides the reflected and emitted light beam to positioning marks 22 and 25 to two bodies of a reticle and a wafer. The reflecting surfaces 31 and 32 are arranged so that the intersecting angle alpha formed by the reflecting surfaces 31 and 32 and the angle theta formed by both beams of the incident light beam and the emitted light beam have the relationship of theta = 2alpha. Even if the incident angle of the light beam with respect to the reflecting surface 31 is changed, the angle theta formed by the incident light beam and the emitted light beam is kept constant. The incident angles of thelight beam emitted from the reflecting surface 32 at the position aligning marks 22 and 25 are kept constant. Therefore, the detecting error caused by the position deviation data between the reticle and the wafer does not occur. |
