Method of detecting positions

• US 5,500,736 A
• Filed: 11/07/1994
• Issued: 03/19/1996
• Est. Priority Date: 07/29/1992
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Yanagihara, Masamitsu, Hazama, Junji, Koitabashi, Hideki
• Primary Examiner(s): Pham, Hoa Q.
• Application Number:
  US08/339,284
• Time in Patent Office: 498 Days
• Field of Search: 356/372, 356/375, 356/394, 356/399-401, 250/548, 250/561, 382/8, 382/48, 382/61
• US Class Current: 356/620
• CPC Class Codes: G03F 9/70 for microlithography measuring printed patterns for monitoring overlay G03F7/70633 or focus G03F7/70641; projection system adjustment G03F7/70258; position control G03F7/70775

Abstract

A position detecting method detects each position of a photosensitive substrate when executing shots of circuit patterns so that the circuit patterns are further superposed on the photosensitive substrate already formed with the circuit patterns. The method comprises the steps of performing a shot of a circuit pattern of a reticle in superposition on liquid crystal pixel segments already formed on a glass plate, registering, in a memory, a circuit pattern as a reference image in the liquid crystal pixel segment and performing pattern matching with other fields of the liquid crystal pixel segments by use of this reference image. An alignment is conducted based on a position of circuit pattern extracted thereby.

Claims

1. A method of detecting position of a substrate formed with at least one pattern field in which a plurality of pattern elements having a predetermined shape to form a circuit pattern are repeatedly disposed at a predetermined interval, said method comprising the steps of:

(a) imaging, as a first processed image, a part of said at least one pattern field;

(b) storing, as a reference image, at least one first video signal of images of said pattern elements within said first processed image and obtaining a position of said first video signal in said first processed image;

(c) imaging a part of said at least one pattern field including a pattern element different from said pattern elements in step (b) by moving said substrate by a distance corresponding to said predetermined interval and detecting a second video signal as a second processed image;

(d) detecting a video signal corresponding to said reference image from said second video signal and detecting a position of said corresponding video signal in said second processed image; and

(e) detecting a position of said substrate based on a position of said first video signal and a position of said corresponding video signal.

2. A method according to claim 1, further comprising the step of detecting a position of a fiducial mark formed off of said at least one pattern field, prior to said storing of said at least one video signal, and wherein said plurality of pattern elements have a predetermined positional relationship with said fiducial mark.