Microlithographic reduction projection catadioptric objective

A microlithographic reduction projection catadioptric objective devoid of planar folding mirrors and comprising an aperture plane on an image side of a most imageward curved mirror.

A microlithographic reduction projection catadioptric objective, wherein after a most imageward mirror, an incident beam is diverging.

A microlithographic reduction projection catadioptric objective, comprising an unobscured system comprising a straight axis of symmetry of all curvatures of all optical elements, wherein no more than two optical elements are cut to deviate substantially from disk form.

A microlithographic reduction projection catadioptric objective consisting of in sequence, from an object side to an image side, of a catadioptric group giving a real intermediate image, an optical group selected from the group of optical groups consisting of a catoptric group and a catadioptric group for providing a virtual image, and a dioptric group for providing a real image.

A microlithographic reduction projection catadioptric objective having a positive overall reduction ratio, and comprising a focussing lens group downstream of a catadioptric group including mirrors having a negative reduction ratio.

A microlithographic reduction projection catadioptric objective comprising in sequence, from an object side to an image side, a field lens group, a catadioptric group comprising one or more negative lenses and a concave mirror generating axial chromatic aberration, a group comprising an odd number of mirrors, and a positive lens group.

A microlithographic reduction projection catadioptric objective comprising in sequence, from an object side to an image side, a catadioptric group comprising one mirror and having a negative reduction ratio, a group comprising an odd number of mirrors and having a positive reduction ratio, and a dioptric lens group having a negative reduction ratio.

A microlithographic reduction projection catadioptric objective, wherein a most imageward mirror is convex.

A microlithographic reduction projection catadioptric objective, having an object side and an image side, comprising an even number greater than two of curved mirrors with an unobscured system aperture and including more lenses than curved mirrors, being devoid of planar folding mirrors and comprising an aperture plane on the image side of a most imageward curved mirror.

A microlithographic reduction projection catadioptric objective having an object side and an image side, comprising an even number greater than two of curved mirrors, with an unobscured system aperture and including more lenses than curved mirrors, wherein after a more imageward curved mirror the beam diverges.

A microlithographic reduction projection objective, k comprising four curved mirrors and more than eight lenses forming a system with an unobscured pupil, comprising a straight axis of symmetry of all curvatures of all optical elements, wherein no more than two optical elements deviate substantially from disk form.

A microlithographic reduction projection objective having an object side and an image side, comprising more than two curved mirrors and no more than one optical element that is in a substantially non rotationally symmetric form, consisting of in sequence from the object side to the image side, a catadioptric group providing a real intermediate image, an optical group selected from the group of optical groups consisting of a catoptric group and a catadioptric group, for providing a virtual image, and a dioptric group providing a real image.

A photolithographic reduction projection catadioptric objective, comprising:

• a first optical group including an even number of at least four mirrors for producing a virtual intermediate image for reduction by the second optical group which receives the virtual image;
• and
• a second substantially refractive optical group more imageward than said first optical group including a number of lenses and having a negative overall magnifying power for providing image reduction.

A photolithographic reduction projection catadioptric objective, comprising:

• a first optical group including an even number of at least four mirrors including a convex most imageward mirror;
• and
• a second substantially refractive optical group more imageward than said first optical group for receiving a beam from the convex most imageward mirror of the first group and including a number of lenses for providing image reduction.