Projection optical system and exposure apparatus using the same

Claim 2

A projection optical system according to claim 1, wherein when I is an axial distance from said first object to a first-object-side focal point of said entire projection optical system and L is the distance from said first object to said second object, the following condition is satisfied: 1.0 < I/L.

Claim 3

A projection optical system according to claim 1, wherein said fourth lens group comprises: a front lens group disposed as closest to the first object, said front lens group having two negative meniscus lenses each shaped with a concave surface to said second object; a rear lens group disposed as closest to the second object, said rear lens group having a negative lens with a concave surface to said first object; and an intermediate lens group disposed between said front lens group in said fourth lens group and said rear lens group in said fourth lens group, said intermediate lens group having first and second negative lenses in order from the side of said first object, and wherein when f 4A is a focal length of said first negative lens in said fourth lens group and f 4B is a focal length of said second negative lens in said fourth lens group, the following condition is satisfied: 0.05 < f 4A /f 4B < 20.

Claim 4

A projection optical system according to claim 1, wherein when F 2Ff is a radius of curvature of a first-object-side surface of said front lens and r 2Fr is a radius of curvature of a second-object-side surface of said front lens, the front lens in said second lens group satisfies the following condition: 1.00 ≦ (r 2Ff - r 2Fr )/(r 2Ff + r 2Fr ) < 5.0.

Claim 5

A projection optical system according to claim 1, wherein said fourth lens group has: a front lens group having a negative lens disposed as closest to said first object and shaped with a concave surface to said second object; a rear lens group having a negative lens disposed as closest to the second object and shaped with a concave surface to said first object; and an intermediate lens group having a negative lens and a positive lens with a convex surface adjacent to a concave surface of said negative lens is disposed between said front lens group in said fourth lens group and said rear lens group in said fourth lens group, and wherein when r 4N is a radius of curvature of said concave surface of the negative lens in said intermediate lens group and r 4P is a radius of curvature of said convex surface of the positive lens in said intermediate lens group, the following condition is satisfied: -0.9 < (r 4N - r 4P )/(r 4N + r 4P ) < 0.9, provided that when L is the distance from said first object to said second object, said concave surface of said negative lens in said intermediate lens group or said convex surface of said positive lens in said intermediate lens group satisfies at least one of the following conditions: [r 4N /L| < 2.0 |r 4P /L| < 2.0.

Claim 6

A projection optical system according to claim 1, wherein when f 22 is a focal length of the second lens with the negative refracting power in said second lens group and f 23 is a focal length of the third lens with the negative refracting power in said second lens group, the following condition is satisfied: 0.1 < f 22 /f 23 < 10.

Claim 7

A projection optical system according to claim 1, wherein said fifth lens group has a negative meniscus lens, and a positive lens disposed as adjacent to a concave surface of said negative meniscus lens and having a convex surface opposed to the concave surface of said negative meniscus lens, and wherein when r 5n is a radius of curvature of the concave surface of said negative meniscus lens in said fifth lens group and r 5P is a radius of curvature of the convex surface, opposed to the concave surface of the negative meniscus lens, of the positive lens disposed as adjacent to the concave surface of said negative meniscus lens in said fifth lens group, the following condition is satisfied: 0 < (r 5P - r 5n )/(r 5P + r 5n ) < 1.

Claim 8

A projection optical system according to claim 7, wherein said negative meniscus lens and said positive lens adjacent to the concave surface of said negative meniscus lens are disposed between at least one positive lens in said fifth lens group and at least one positive lens in said fifth lens group.

Claim 9

A projection optical system according to claim 1, wherein said fifth lens group has a negative lens disposed as closest to the second object and shaped with a concave surface to the second object and the sixth lens group has a lens disposed as closest to the first object and shaped with a convex surface to the first object, and wherein when r 5R is a radius of curvature of a second-object-side surface of the negative lens disposed as closest to the second object in said fifth lens group and r 6F is a radius of curvature of a first-object-side surface of the lens disposed as closest to the first object in said sixth lens group, the following condition is satisfied: -0.90 < (r 5R - r 6F )/(r 5R + r 6F ) < -0.001.

Claim 10

A projection optical system according to claim 1, wherein when d 56 is a lens group separation between said fifth lens group and said sixth lens group and L is the distance from said first object to said second object, the following condition is satisfied: d 56 /L < 0.017.

Claim 11

A projection optical system according to claim 1, wherein when r 6F is a radius of curvature of a lens surface closest to the first object in said sixth lens group and d 6 is an axial distance from the lens surface closest to the first object in said sixth lens group to the second object, the following condition is satisfied: 0.50 < d 6 /r 6F < 1.50.

Claim 12

A projection optical system according to claim 1, wherein said fifth lens group has a negative lens disposed as closest to the second object and shaped with a concave surface to the second object, and wherein when r 5F is a radius of curvature of a first-object-side surface of the negative lens disposed as closest to the second object in said fifth lens group and r 5R is a radius of curvature of a second-object-side surface of the negative lens disposed as closest to the second object in said fifth lens group, the following condition is satisfied: 0.30 < (r 5F - r 5R )/(r 5F + r 5R ) < 1.28.

Claim 13

A projection optical system according to claim 1, wherein when f 21 is a focal length of the first lens with the positive refracting power in the intermediate lens group in said second lens group and L is the distance from said first object to said second object, the following condition is satisfied: 0.230 < f 21 /L < 0.40.

Claim 14

A projection optical system according to claim 1, wherein when f 2F is a focal length of the front lens with the negative refracting power disposed as closest to the first object in said second lens group and shaped with the concave surface to said second object and f 2R is a focal length of the rear lens with the negative refracting power disposed as closest to the second object in said second lens group and shaped with the concave surface to said first object, the following condition is satisfied: 0 ≦ f 2F /f 2R < 18.

Claim 15

A projection optical system according to claim 1, wherein the intermediate lens group in said second lens group has a negative refracting power.

Claim 16

A projection optical system according to claim 1, wherein said first lens group has at least two positive lenses, said third lens group has at least three positive lenses, said fourth lens group has at least three negative lenses, said fifth lens group has at least five positive lenses and at least one negative lens, and said sixth lens group has at least one positive lens.

Claim 17

A projection optical system according to claim 1, wherein said sixth lens group comprises three or less lenses having at least one lens surface satisfying the following condition: 1/|ΦL| < 20 where   Φ: a refractive power of said lens surface, and L: the object-to-image distance from said first object to said second object.

Claim 18

A projection optical system according to claim 1, wherein a magnification of said projection optical system is 1/5.

Claim 19

An exposure apparatus comprising: a stage allowing a photosensitive substrate to be held on a main surface thereof; an illumination optical system for emitting exposure light of a predetermined wavelength and transferring a predetermined pattern of a mask onto said substrate; and a projection optical system provided between said mask and said substrate, said projection optical system including a first lens group with a positive refracting power, a second lens group with a negative refracting power, a third lens group with a positive refracting power, a fourth lens group with a negative refracting power, a fifth lens group with a positive refracting power, and a sixth lens group with a positive refracting power in order from the side of said mask, wherein said second lens group comprises a front lens with a negative refracting power disposed as closest to said first object and shaped with a concave surface to said second object, a rear lens of a negative meniscus shape disposed as closest to said second object and shaped with a concave surface to said mask, and an intermediate lens group disposed between said front lens and said rear lens, said intermediate lens group having a first lens with a positive refracting power, a second lens with a negative refracting power, and a third lens with a negative refracting power in order from the side of said mask, and wherein when f 1 is a focal length of said first lens group, f 2 is a focal length of said second lens group, f 3 is a focal length of said third lens group, f 4 is a focal length of said fourth lens group, f 5 is a focal length of said fifth lens group, f 6 is a focal length of said sixth lens group, and L is a distance from said mask to said substrate, the following conditions are satisfied: f 1 /L < 0.8 -0.033 < f 2 /L 0.01 < f 3 /L < 1.0 f 4 /L < -0.005 0.01 < f 5 /L < 0.9 0.02 < f 6 /L < 1.6.

Claim 20

An exposure apparatus according to claim 19, wherein a magnification of said projection optical system is 1/5.