Device for projecting mask pattern onto substrate

Abstract

Abstract PURPOSE: To provide a device for correcting focusing error with a simple structure, by providing a correction element which allows only a sub-beam deflected as primary diffraction light to be deflected and focused on the second alignment mark by the first alignment mark of alignment beam. CONSTITUTION: An alignment beam (b) incident on a grating P2 is split into zero-order sub-beam b (0), primary sub-beam (+1) and b (-1), and such high- order beam as 3-order and 4-order, etc. The primary sub-beam is incident on a correction lens positioned at a surface 24. The correction lens has such lens power that direction of the primary sub-beam b (-) and b (+1) is so displaced that the main light ray of the primary sub-beam b (+1) and the main light ray of b (-) cross each other in the plane of a mask alignment mark M2 . In addition, the correction lens's aperture is appropriately small, so that a high-order beam diffracted at a diffraction angle larger than the primary sub- beam does not pass the correction lens. Further, with an element assigned at the position of correction lens, the element blocks the zero-order sub-beam from passing the correction lens.

Inventors

• 👤 Stefan Wittekoek
• 👤 ステファン　ウィッテコック
• 👤 Den Brink Marinus A Van
• 👤 マリヌス　アールト　ファン　デン　ブリンク

Bibliographic Details