Alignment system for exposure apparatus

• US 4,962,318 A
• Filed: 08/17/1989
• Issued: 10/09/1990
• Est. Priority Date: 08/19/1988
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Nishi, Kenji
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Shami, K.
• Application Number:
  US07/395,078
• Time in Patent Office: 418 Days
• Field of Search: 250/548, 250/557, 250/561, 356/399-401, 356/141, 356/152
• US Class Current: 250/548
• CPC Class Codes: G03F 9/7049 Technique, e.g. interferometric
• CPC Class Codes: G03F 9/7088 Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection

Abstract

An exposure apparatus for transferring a mask pattern to a wafer having a surface photoresist layer. The apparatus is comprised of first and second detectors and a determination unit. The first detector includes a light-emitting system for generating first light to illuminate first marks on the substrate and provides first position data. The second mark position detector includes a light-emitting system for generating second light having a wider wavelength distribution than that of the first light to illuminate second marks on the substrate and provides second position data. Determination unit (EGA operational unit 502 or the like) is provided for determining the position of the substrate as a whole by using both of the first and second position data.

Claims

1. An exposure apparatus for transferring a mask pattern to a wafer having a surface photoresist layer sensitive to a predetermined wavelength range, comprising:

first mark position detection means for illuminating said wafer with single wavelength or quasi monochromatic light as first light, detecting a first mark on said wafer illuminated by said first light and providing first position data concerning the position of said first mark according to the result of said first mark detection;

second mark position detection means for illuminating said wafer with light having a wider wavelength distribution than said first light as second light, detecting a second mark on said wafer illuminated by said second light and providing second position data concerning the position of said second mark according to the result of said second mark detection; and

position determination means for determining relative positions of said wafer and said mark according to both said first and second position data.

2. The exposure apparatus according to claim 1, wherein said exposure apparatus further comprises an optical projecting system for focusing said mask pattern on said wafer and a stage moved with said wafer supported thereon two-dimensionally along a mask pattern image projection surface of said optical projecting system to successively change in image projection position on said wafer, said first mark position detection means for photoelectrically detecting said first mark provided on each said image projection position on said wafer via said optical projecting system, and said second mark position detection means disposed at a predetermined distance from said optical projecting system for photoelectrically detecting said second mark provided at each said image projection position on said wafer.

3. The exposure apparatus according to claim 2, wherein said position determination means includes means for statistically determining the position of a map of said image projection positions on said wafer.

4. The exposure apparatus according to claim 1, wherein said marks are formed in a common mark pattern.