Patent ID: 8599387
Filing Date: 2013-12-03
Classification: G03F

Abstract:
1. A surface position detecting apparatus, comprising: a light-sending optical system including a first lens system, the light-sending optical system guiding light to a detection target surface via the first lens system; a light-receiving optical system including a second lens system, the light-receiving optical system guiding the light reflected by the detection target surface to a light-receiving surface via the second lens system; a detector which detects the light via the light-receiving surface; a splitter arranged on an optical path between the first lens system and the detection target surface, which splits the light emerged from the first lens system into a first light and a second light; and a combiner arranged in an optical path between the detection target surface and the second lens system, which combines the first light reflected by the detection target surface with the second light which does not pass via the detection target surface, to orient the combined light toward the light receiving surface; wherein the first light and the second light are guided from the splitter to the combiner without passing through any lens system, wherein the detector detects the first light and the second light via the light receiving surface, to provide information regarding a surface position of the detection target surface on the basis of detection results of the first light and the second light.