Microlithographic reduction projection catadioptric objective

A microlithographic reduction projection catadioptric objective comprising an object plane and an image plane, a plurality of curved mirrors and a light path propagating from said object plane imageward to said image plane, the light path being folded at each curved mirror, wherein after a curved mirror arranged most imageward on the light path, an incident beam is diverging and the light path from said curved mirror to the image plane is free of any intermediate image.

A microlithographic reduction projection catadioptric objective including an even number greater than two of mirrors and more lenses than mirrors, wherein after a most imageward mirror, an incident beam is diverging.

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

A microlithographic reduction projection catadioptric objective having at least two mirrors and more lenses than mirrors, wherein a most imageward mirror is convex and a light path from the most imageward convex mirror to an image plane is free of any intermediate image.

A microlithographic reduction projection catadioptric objective, having an object side and an image side, comprising an even number greater than two of curved mirrors, being devoid of planar folding mirrors and comprising an aperture plane on the image side of a most imageward curved mirror, wherein after a most imageward mirror, an incident beam is diverging.

A microlithographic reduction projection catadioptric objectve 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 most imageward curved mirror the beam diverges.

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 received the virtual image;
• and
• a second substantially refractive optical group more imageforward than said first optical group including a number of lenses and having a negative overall magnifying power for providing image reduction, wherein after a most imageward mirror of the first optical group, an incident beam is diverging.

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.