Broad band optical reduction system using matched multiple refractive element materials
AssigneeSVG Lithography Systems, Inc.
InventorsDavid Williamson, Satish DeSai
Life of this patent
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Abstract
A broad band catadioptric optical reduction system using refractive elements made of different types of glass matched for color correction over a broad band width. A combination of fused silica and crown glass is used. An aspheric mirror is used for improved aberration correction. The optical system is adapted for use in lithography for semiconductor manufacturing in the I-line and is capable of 0.5 micron resolution at a wavelength of 365 nanometers.
Claims13
A catadioptric optical reduction system, from the long conjugate end to the short conjugate end comprising:
- a first lens group, said first lens group including refractive elements made from at least two different materials;
- a second lens group, said second lens group including refractive elements made from at least two different materials;
- a beamsplitter;
- a third lens;
- a reduction mirror;
- and
- a fourth lens group, said fourth lens group including refractive elements made from at least two different materials
- arranged such that radiation entering the system passes through said first lens group, said second lens group, said beamsplitter, said third lens, is reflected by said mirror back through said third lens, through said beamsplitter, and through said fourth lens group.
A catadioptric optical reduction system for use in photolithography as applied to semiconductor manufacturing, from the long conjugate end to the short conjugate end comprising:
- a first positive lens made from crown glass;
- a first negative lens made from fused silica glass;
- a second positive lens made from fused silica glass;
- a folding mirror;
- a second negative lens made from fused silica glass;
- a third positive lens made from crown glass;
- a beamsplitter made from fused silica glass;
- a quarter wave plate made from fused silica glass;
- a third negative lens made from crown glass;
- an aspheric reduction mirror;
- a fourth positive lens made from crown glass;
- a first shell made from fused silica;
- a second shell made from fused silica;
- a fifth positive lens made from fused silica;
- a sixth positive lens made from crown glass;
- arranged such that radiation entering said system passes through said first positive lens, said first negative lens, said second positive lens, and is folded by said folding mirror, and passes through said second negative lens and said third positive lens, and is reflected by said beamsplitter through said quarter wave plate and said third negative lens and is reflected by said aspheric reduction mirror back through said beamsplitter, and through said fourth positive lens, said first shell, said second shell, said fifth positive lens, and said sixth positive lens.
A catadioptric optical reduction system for use in photolithography as applied to semiconductor manufacturing having the following prescription:
- TABLE I ______________________________________ Surface Surface Radius Thickness Number Shape (mm) (mm) Glass ______________________________________ 1 Spherical Infinite 194.1150 Air 2 Spherical -1184.7428 13.6174 FK 5 3 Spherical -616.5730 11.9192 Air 4 Spherical 276.4000 17.8788 FQTZ 5 Spherical 210.0800 25.6556 Air 6 Spherical 262.3992 22.8571 FQTZ 7 Spherical -1569.5990 115.8881 Air 8 Spherical Infinite 0.0000 -Air 9 Spherical Infinite -163.8330 -Air 10 Spherical -343.1990 -13.5000 -FQTZ 11 Spherical -169.4590 -11.6302 -Air 12 Spherical -417.6020 -14.6810 -FK 5 13 Spherical 519.0970 -37.3559 -Air 14 Spherical Infinite -59.0000 -FQTZ 15 Spherical Infinite -59.0000 -FQTZ 16 Spherical Infinite 59.0000 FQTZ 17 Spherical Infinite 2.0000 Air 18 Spherical Infinite 4.5000 FQTZ 19 Spherical Infinite 9.2000 Air 20 Spherical -263.3700 6.6000 FK 5 21 Spherical -537.1682 4.5000 Air 22 Aspherical -291.8474 -4.5000 -Air 23 Spherical -537.1682 -6.6000 -FK 5 24 Spherical -263.3700 -9.2000 -Air 25 Spherical Infinite -4.5000 -FQTZ 26 Spherical Infinite -2.0000 -Air 27 Spherical Infinite -118.0000 -FQTZ 28 Spherical Infinite -1.0000 -Air 29 Spherical -85.0630 -9.9285 -FK 5 30 Spherical -413.4166 -1.0000 -Air 31 Spherical -41.6090 -7.2704 -FQTZ 32 Spherical -37.1820 -6.7667 -Air 33 Spherical -53.0900 -7.8493 -FQTZ 34 Spherical -52.3059 -5.6405 -Air 35 Spherical -101.9830 -25.3250 -FQTZ 36 Spherical -111.4400 -2.8000 -Air 37 Spherical -75.0130 -5.7500 -FK 5 38 Spherical -678.6834 -3.9999 -Air 39 Spherical Infinite 0.0000 -Air ______________________________________
- wherein the aspherical surface has the following aspheric coefficients,
- TABLE II __________________________________________________________________________ Number E A(4) A(6) A(8) A(10) __________________________________________________________________________ 22 1.00 -2.733860 .times. 10.sup.-9 -5.28608 .times. 10.sup.-14 0 0 __________________________________________________________________________
Dependencies are inferred from the claim text.