Position measurement apparatus and exposure apparatus which measure position of object using reference mark, and method of manufacturing device

摘要

A position measurement apparatus that measures a position of an object using a reference mark includes a first illumination optical system configured to illuminate the object using measurement light from a light source which emits light of a first wavelength band, a second illumination optical system configured to illuminate the reference mark using reference light of a second wavelength band, and a position measurement unit configured to detect light from the object and light from the reference mark and to obtain the position of the object based on the detection result, and the second wavelength band of the reference light is set between an upper limit and a lower limit of the first wavelength band of the measurement light from the light source.

主权项

1. A position measurement apparatus that measures a position of an object, the position measurement apparatus comprising:
an image sensor; a first illumination optical system configured to illuminate a mark of the object using measurement light in a first wavelength band; an imaging optical system configured to cause light from the object illuminated by the measurement light in the first wavelength band to image on the image sensor; a reference mark configured to be arranged outside an optical path of the first illumination optical system and the imaging optical system; a second illumination optical system configured to illuminate the reference mark using reference light of a second wavelength band; an optical element configured to guide light from the reference mark illuminated by the reference light of the second wavelength band to the image sensor through the optical path of the imaging optical system; and a position measurement unit configured to detect the position of the object based on an image of the object and an image of the reference mark detected by the image sensor, wherein the second wavelength band of the reference light is set between an upper limit and a lower limit of the first wavelength band, wherein the optical element is a mirror which transmits a part of incident light and reflects another part of the incident light, and wherein an optical characteristic of the mirror is set so that light amount of light arriving at the image sensor from the object through the mirror is larger than that arriving at the image sensor from the reference mark through the mirror.