Patent ID: 8502978
Filing Date: 2013-08-06
Classification: G03F

Abstract:
1. A surface position detecting apparatus for detecting a surface position of a predetermined surface, said apparatus comprising: a light-sending optical system which makes first light from a first pattern and second light from a second pattern incident at different incidence angles to the predetermined surface to project an intermediate image of the first pattern and an intermediate image of the second pattern onto the predetermined surface; a light-receiving optical system which guides the first light and the second light reflected by the predetermined surface, to a first observation surface and to a second observation surface, respectively, to form an observation image of the first pattern on the first observation surface and an observation image of the second pattern on the second observation surface; and a detecting section which detects a piece of position information of the observation image of the first pattern on the first observation surface and a piece of position information of the observation image of the second pattern on the second observation surface and which calculates a surface position of the predetermined surface, based on the pieces of position information, wherein the light-sending optical system has at least one sending-side common optical member provided in common to the first light and the second light, and a sending-side reflecting section which reflects the second light having passed via the sending-side common optical member, an even number of times to make the second light incident at the incidence angle smaller than that of the first light to the predetermined surface, wherein the sending-side reflecting section is arranged immediately above the predetermined surface, and wherein the light-sending optical system has a sending-side deflecting section which deflects the first light and the second light having passed via the sending-side common optical member, relative to each other to guide the first light to the predetermined surface and the second light to the sending-side reflecting section.