Objective for an IC mask testing device

Claim 2

An objective for an IC mask testing device comprising a first, second, third, fourth, fifth and sixth lens components, said first lens component being a positive meniscus lens, said second lens component being a biconvex lens, said third lens component being a cemented doublet consisting of a biconvex lens and a biconcave lens, said fourth lens component being a cemented doublet consisting of a biconcave lens and a biconvex lens, said fifth lens component being a biconvex lens, said sixth lens component being a negative meniscus lens, said objective for an IC mask testing device being arranged to fulfill the conditions (1) through (5) shown below: (1) 1.2f<f.sub.p <1.8f (2) 1.5f<f.sub.1 (3) d.sub.1 <0.36f (4) 1.27f<r.sub.13 <1.40f (5) 1.0f<r.sub.14 <1.05f where, reference symbol f represents the focal length of the lens system as a whole, reference symbol f p represents the total focal length of the first through the fifth lens components, reference symbol f 1 represents the focal length of the first lens component, and reference symbol d 1 represents the thickness of the first lens component, and reference symbols r 13 and r 14 respectively represent radii of curvature of respective surfaces of the sixth lens component.

Claim 3

An objective for an IC mask testing device according to claim 1 further fulfilling the conditions (6) and (10) shown below: (6) ν.sub.2, ν.sub.3, ν.sub.6 >65 (10) ν.sub.4, ν.sub.5,<40 where, reference symbols ν 2 , ν 3 and ν 6 respectively represent Abbe's numbers of the second lens component, lens element on the object side in the third lens component, and lens elements on the image side in the fourth lens component, and reference symbols ν 4 and ν 5 respectively represent Abbe's numbers of the lens element on the image side in the third lens component and lens element on the object side in the fourth lens component.

Claim 4

An objective for an IC mask testing device according to claim 2 further fulfilling the conditions (7) through (9) shown below: (7) 0.6f<d.sub.13 <0.7f (8) 0.03f<d.sub.12 <0.13f (9) n.sub.4, n.sub.5 >1.65 where, reference symbol d 13 represents the thickness of the sixth lens component, reference symbol d 12 represents the airspace between the fifth and sixth lens components, and reference symbols n 4 and n 5 respectively represent refractive indices of the lens element on the image side in the third lens component and lens element on the object side in the fourth lens component.

Claim 5

An objective for an IC mask testing device according to claim 3, in which said objective for an IC mask testing device has the following numerical data: ______________________________________ r.sub.1 = -0.907 d.sub.1 = 0.347 n.sub.1 = 1.72916 ν.sub.1 = 54.68 r.sub.2 = -0.692 d.sub.2 = 0.017 r.sub.3 = 1.287 d.sub.3 = 0.268 n.sub.2 = 1.49700 ν.sub.2 = 81.61 r.sub.4 = -1.517 d.sub.4 = 0.017 r.sub.5 = 0.789 d.sub.5 = 0.330 n.sub.3 = 1.49700 ν.sub.3 = 81.61 r.sub.6 = -7.468 d.sub.6 = 0.267 n.sub.4 = 1.65128 ν.sub.4 = 38.25 r.sub.7 = 0.573 d.sub.7 = 0.309 r.sub.8 = -0.419 d.sub.8 = 0.124 n.sub.5 = 1.72047 ν.sub.5 = 34.72 r.sub.9 = 1.892 d.sub.9 = 0.361 n.sub.6 = 1.51728 ν.sub.6 = 69.56 r.sub.10 = -0.758 d.sub.10 = 0.019 r.sub.11 = 7.471 d.sub.11 = 0.253 n.sub.7 = 1.65830 ν.sub.7 = 57.33 r.sub.12 = -1.314 d.sub.12 = 0.050 r.sub.13 = 1.354 d.sub.13 = 0.699 n.sub.8 = 1.78650 ν.sub.8 = 50.00 r.sub.14 = 1.032 f = 1, NA = 0.4, magnification 140X fp = 1.31, f.sub.1 = 2.38, WD = 0.478 ______________________________________ where, reference symbols r 1 through r 14 respectively represent radii of curvature of respective lens surfaces, reference symbols d 1 through d 13 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n 1 through n 8 respectively represent refractive indices of respective lenses for d-line, and reference symbols ν 1 through ν 8 respectively represent Abbe's numbers of respective lenses for d-line.

Claim 6

An objective for an IC mask testing device according to claim 3, in which said objective for an IC mask testing device has the following numerical data: ______________________________________ r.sub.1 = 0.903 d.sub.1 = 0.343 n.sub.1 = 1.72916 ν.sub.1 = 54.68 r.sub.2 = -0.651 d.sub.2 = 0.017 r.sub.3 = 1.652 d.sub.3 = 0.266 n.sub.2 = 1.49700 ν.sub.2 = 81.61 r.sub.4 = -1.333 d.sub.4 = 0.017 r.sub.5 = 0.641 d.sub.5 = 0.327 n.sub.3 = 1.49700 ν.sub.3 = 81.61 r.sub.6 = -3.387 d.sub.6 = 0.265 n.sub.4 = 1.65412 ν.sub.4 = 39.70 r.sub.7 = 0.514 d.sub.7 = 0.306 r.sub.8 = -0.426 d.sub.8 = 0.265 n.sub.5 = 1.72047 ν.sub.5 = 34.72 r.sub.9 = 1.579 d.sub.9 = 0.327 n.sub.6 = 1.51821 ν.sub.6 = 65.04 r.sub.10 = -0.803 d.sub.10 = 0.018 r.sub.11 = 4.165 d.sub.11 = 0.266 n.sub.7 = 1.65830 ν.sub.7 = 57.33 r.sub.12 = -1.636 d.sub.12 = 0.049 r.sub.13 = 1.286 d.sub.13 = 0.615 n.sub.8 = 1.78650 ν.sub.8 = 50.00 r.sub.14 = 1.023 f = 1, NA = 0.4, magnification 140X fp = 1.22, f.sub.1 = 1.855, WD = 0.425 ______________________________________ where, reference symbols r 1 through r 14 respectively represent radii of curvature of respective lens surfaces, reference symbols d 1 through d 13 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n 1 through n 8 respectively represent refractive indices of respective lenses for d-line, and reference symbols ν 1 through ν 8 respectively represent Abbe's numbers of respective lenses for d-line.

Claim 7

An objective for an IC mask testing device according to claim 3, in which said objective for an IC mask testing device has the following numerical data: ______________________________________ r.sub.1 = -0.901 d.sub.1 = 0.317 n.sub.1 = 1.72916 ν.sub.1 = 54.68 r.sub.2 = -0.645 d.sub.2 = 0.017 r.sub.3 = 1.396 d.sub.3 = 0.266 n.sub.2 = 1.49700 ν.sub.2 = 81.61 r.sub.4 = -1.569 d.sub.4 = 0.017 r.sub.5 = 0.749 d.sub.5 = 0.328 n.sub.3 = 1.49700 ν.sub.3 = 81.61 r.sub.6 = -5.979 d.sub.6 = 0.266 n.sub.4 = 1.66998 ν.sub.4 = 39.32 r.sub.7 = 0.534 d.sub.7 = 0.307 r.sub.8 = -0.408 d.sub.8 = 0.123 n.sub.5 = 1.72047 ν.sub.5 = 34.72 r.sub.9 = 6.597 d.sub.9 = 0.359 n.sub.6 = 1.49700 ν.sub.6 = 81.61 r.sub.10 = -0.647 d.sub.10 = 0.018 r.sub.11 = 4.339 d.sub.11 = 0.252 n.sub.7 = 1.65830 ν.sub.7 = 57.33 r.sub.12 = -1.697 d.sub.12 = 0.127 r.sub.13 = 1.341 d.sub.13 = 0.617 n.sub.8 = 1.78650 ν.sub.8 = 50.00 r.sub.14 = 1.016 f = 1, NA = 0.4, magnification 140X fp = 1.26, f.sub.1 = 2.03, WD = 0.412 ______________________________________ where, reference symbols r 1 through r 14 respectively represent radii of curvature of respective lens surfaces, reference symbols d 1 through d 13 respectively represent thicknesses of respective lenses and airspaces between respective lenses, reference symbols n 1 through n 8 respectively represent refractive indices of respective lenses for d-line, and reference symbols ν 1 through ν 8 respectively represent Abbe's numbers of respective lenses for d-line.