Unit magnification large-format catadioptric lens for microlithography

1. A microlithographic lens for imaging over an image field at an image plane a photomask that defines a plurality of die at an object plane, comprising along an optical axis:

a concave mirror having an aspheric concave surface;

a positive lens group spaced apart from the concave surface of the concave mirror;

first and second total-internal-reflection (TIR) prisms disposed adjacent the positive lens group opposite the concave mirror and on respective sides of the optical axis, with the first prism having a first surface adjacent the object plane and the second prism having a second surface adjacent the image plane, wherein each prism has a refractive index of 1.5357 or greater at an i-line wavelength and respective TIR surfaces each having a phase-preserving coating;

wherein the positive lens group consists of either three or four air-spaced lens elements, with one of the lens elements being a most mirror-wise lens element, having a positive meniscus shape and including a prism-wise concave aspheric surface; and

wherein the image field is sized to include from four to six die, with each die having a nominal size of 26 mm×34 mm, the lens having substantially unit magnification at a numerical aperture of nominally 0.32, and wherein the lens has a Strehl ratio of >0.95 over the image field for at least an i-line wavelength of light.

2. The microlithographic lens of claim 1 , further comprising a resolution of about 1 micron at a wavelength of 365 nm.

3. The microlithographic lens of claim 1 , further comprising a resolution of about 2 microns for light having g-line, h-line and i-line wavelengths.

4. The microlithographic lens of claim 1 , further comprising an amount of distortion that is less that 100 nm over the image field.

5. The microlithographic lens of claim 1 , further comprising an amount of distortion that is less than 50 nm over the image field.

6. The microlithographic lens of claim 1 , further comprising an amount of distortion that is less than 10 nm over the image field.

7. The microlithographic lens of claim 1 , further comprising a depth of focus of about 3 microns or greater over the image field.

8. The microlithographic lens of claim 1 , wherein the microlithographic lens images light over an i-line LED spectrum.

9. The microlithographic lens of claim 1 , further comprising:

a first protective window disposed between the object plane and the first TIR prism surface; and

a second protective window disposed between the image plane and the second TIR prism surface.

10. The microlithographic lens of claim 9 , wherein the protective windows are each made of fused quartz and have a thickness of about 1 mm.

11. The microlithographic lens of claim 1 , wherein the lens has an amount of non-telecentricity that allows for the unit magnification to be adjusted by up to about 5 parts per million.

12. The microlithographic lens of claim 1 , wherein one of the lens elements includes either a concave surface or a planar surface that resides immediately adjacent the first and second prisms.

13. The microlithographic lens of claim 1 , wherein the image field size is nominally 68 mm×52 mm and accommodates four die.

14. The microlithographic lens of claim 1 , wherein the image field size is nominally 102 mm×52 mm and accommodates six die.

15. A microlithographic lens for imaging over an image field at an image plane a photomask that defines a plurality of die at an object plane, comprising along an optical axis:

a concave mirror having an aspheric concave surface;

a positive lens group spaced apart from the concave surface of the concave mirror and consisting of three spaced-apart lens elements, including a most mirror-wise lens element having a positive meniscus shape and including a prism-wise concave aspheric surface;

first and second total-internal-reflection (TIR) prisms disposed adjacent the positive lens group opposite the concave mirror and on respective sides of the optical axis, with the first prism having a first surface adjacent the object plane and the second prism having a second surface adjacent the image plane, wherein each prism has a refractive index of 1.5357 or greater at an i-line wavelength and respective TIR surfaces each having a phase-preserving coating; and

wherein the image field is sized to include six die, with each die having a nominal size of 26 mm×34 mm, the lens having substantially unit magnification at a numerical aperture of nominally 0.32, and wherein the lens has a Strehl ratio of >0.95 over the image field for either an i-line LED wavelength spectrum or for g-line, h-line and i-line light.

16. The microlithographic lens of claim 15 , wherein the lens has an amount of non-telecentricity that allows for the unit magnification to be adjusted by up to about 5 parts per million.

17. The microlithographic lens of claim 15 , wherein the image field size is nominally 102 mm×52 mm.

18. A microlithographic lens for imaging over an image field at an image plane a photomask that defines a plurality of die at an object plane, comprising along an optical axis:

a concave mirror having an aspheric concave surface;

first and second total-internal-reflection (TIR) prisms disposed on respective sides of the optical axis, with the first prism having a first surface adjacent the object plane and the second prism having a second surface adjacent the image plane, wherein each prism has a refractive index of 1.5357 or greater at an i-line wavelength and respective TIR surfaces each having a phase-preserving coating;

a positive lens group spaced apart from the concave surface of the concave mirror and between the prisms and the concave mirror, the positive lens group consisting of four spaced-apart lens elements, including a most mirror-wise lens element that has a positive meniscus shape and a prism-wise concave aspheric surface and a most prism-wise lens element that has a prism-wise concave surface that resides adjacent the prisms; and

wherein the image field is sized to include four die, with each die having a nominal size of 26 mm×34 mm, the lens having substantially unit magnification at a numerical aperture of nominally 0.32, and wherein the lens has a Strehl ratio of >0.95 over the image field for either an i-line LED wavelength spectrum or for g-line, h-line and i-line light.

19. The microlithographic lens of claim 18 , wherein the image field size is nominally 68 mm×52 mm.

20. The microlithographic lens of claim 18 , further comprising an amount of distortion that is less than 10 nm over the image field.