Illumination optical system and exposure apparatus having the same

• US 6,441,886 B2
• Filed: 10/07/1999
• Issued: 08/27/2002
• Est. Priority Date: 10/08/1998
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Sekine, Yoshiyuki, Suzuki, Akiyoshi
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): NGUYEN, HUNG
• Application Number:
  US09/414,437
• Publication Number:
  US 20020015142A1
• Time in Patent Office: 1,055 Days
• Field of Search: 355/71, 355/73, 355/53, 355/67, 356/400, 378/34, 250/492.2, 250/492.22, 250/458, 359/708, 359/618, 359/629
• US Class Current: 355/71
• CPC Class Codes: G03B 27/54 Lamp housings; Illuminating means
• CPC Class Codes: G03F 7/70091 Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]

Abstract

An illumination optical system for use in an exposure apparatus for projecting a pattern of a mask onto a substrate. The illumination system includes a first beam shape changing optical system for transforming a light, supplied from a light source, into a slit-like light of an oblong shape, and a second beam shape changing optical system for transforming the slit-like light of oblong shape into a slit-like light of an arcuate shape, the second beam shape changing optical system having a prism element. The mask is illuminated with the slit-like light of arcuate shape.

Claims

1. An illumination optical system for use in an exposure apparatus for projecting a pattern of a mask onto a substrate, wherein the mask is to be illuminated with light of an arcuate shape, said illumination optical system comprising:

a first optical system for providing light having a predetermined shape; and

a second optical system for transforming the light of predetermined shape into light of arcuate shape, said second optical system including a first condenser for condensing the light of predetermined shape, a prism element for refracting the light from said first condenser, and a second condenser for condensing the light from said prism element.

9. An exposure apparatus, comprising:

an illumination optical system as recited in any one of claims 1-8, for illuminating a mask having a pattern formed thereon; and

a projection optical system for projecting the pattern of the mask onto a wafer.

10. An apparatus according to claim 9, further comprising scanning means for scanning the mask and the wafer during an exposure process, in a widthwise direction of the slit-like light of arcuate shape.

11. A device manufacturing method, comprising the steps of:

exposing a wafer to a device pattern by using an exposure apparatus as recited in claim 9; and

developing a resist of the exposed wafer.

12. A device manufacturing method, comprising the steps of:

exposing a wafer to a device pattern by using an exposure apparatus as recited in claim 10; and

developing a resist of the exposed wafer.

2. An illumination optical system for use in an exposure apparatus for projecting a pattern of a mask onto a substrate, wherein the mask is to be illuminated with light of an arcuate shape, said illumination optical system comprising:

a first transforming optical system for transforming light, supplied from a light source, into light of an oblong shape; and

a second transforming optical system for transforming the light of oblong shape into light of arcuate shape, said second transforming optical system including a first condenser for condensing the light of oblong shape, a prism element for refracting the light from said first condenser, and a second condenser for condensing the light from said prism element.

3. An illumination optical system according to claim 2, further comprising dividing means for dividing the slit-like light of arcuate shape into plural slit-like lights of arcuate shape, and combining means for combining the plural slit-like lights of arcuate shape along a circumferential direction to provide second slit-like light of arcuate shape being longer, in the circumferential direction, than the slit-like light of arcuate shape provided by said first transforming optical system.

4. An illumination optical system according to claim 2, wherein said second transforming system includes correcting means for correcting dispersion of said prism element.

5. An illumination optical system according to claim 4, wherein said correcting means comprises a diffractive element.

6. An illumination optical system according to claim 4, wherein said correcting means comprises a prism element of the same shape as that of said prism element for refracting the light from said first condenser.

7. An illumination optical system according to claim 2, further comprising luminance distribution adjusting means for adjusting a luminance distribution of the slit-like light of oblong shape so that an illuminance distribution of the slit-like light of arcuate shape becomes substantially uniform.

8. An illumination optical system according to claim 2, wherein said second transforming optical system comprises a first lens for converging the oblong-shaped light and for directing the oblong-shaped light to the prism element, and a second lens for converging the oblong-shaped light to be divergently emitted from the prism element.