US 6,486,940 B1 · High numerical aperture catadioptric lens

Abstract

A catadioptric projection optical system for use in photolithography used in manufacturing semiconductors having a quarter waveplate following a reticle and multiple aspheric surfaces and calcium fluoride lens elements. A quarter waveplate following the reticle eliminates asymmetry in reticle diffraction caused by polarized illumination. The use of additional aspheric surfaces reduces the number of lens elements and aids in reducing aberrations. Calcium fluoride elements are used in the lens group adjacent the wafer to help minimize compaction. In one embodiment, only calcium fluoride material is used. The present invention provides a projection optics system having a numerical aperture of 0.75 for use with wavelengths in the 248, 193, and 157 nanometer range. The object and image locations are separated by a predetermined distance, making possible retrofitting of older optical systems. The present invention is particularly suited for use in semiconductor manufacturing and has improved imaging with less aberrations, particularly at shorter wavelengths.

Claims20

Dependent claims

A catadioptric optical projection system for use in projecting a reduced image of a reticle onto a photosensitive surface, from the long conjugate end to the short conjugate end, comprising:

a first lens group;
a second lens group following said first lens group, one lens in said second lens group having a first aspheric surface;
a beamsplitter placed adjacent said second lens group;
a concave mirror placed adjacent said beamsplitter;
a third lens group placed adjacent said beamsplitter opposite said concave mirror, said third lens group having a majority of the lenses therein made of calcium fluoride,
whereby the reduced image of the reticle is projected onto the photosensitive surface.

3 more elements

An optical reduction system comprising:

a construction substantially according to the following construction data in Table 1
TABLE 1 Element Radius of Radius of Thickness Number Curvature(Front)mm Curvature(Back)mm mm Glass 10 Infinite 71.0257 12 Infinite Infinite 6.0000 Silica space 6.0000 14 Infinite −1637.5100 CX 17.8788 Silica space 7.6907 16 −507.9899 CC 425.0110 CC 23.6604 Silica space 23.6491 18 482.8744 CX −334.9535 CX 32.3037 Silica space 12.0839 20 −210.1022 CC −342.7380 CX 35.5779 Silica space 1.5001 22 254.8364 CX −1377.8565 CX 38.5079 Silica space 83.5499 24 Infinite −64.0738 Reflec- tor 26 −200.6185 CX −294.6182 CC −30.0000 Silica space −33.6639 28 A(1) 207.0105 CX −30.2428 Silica space −1.9989 30 2223.6648 CC −166.4311 CC −27.4282 Silica space −21.5924 31 Infinity Infinity −91.0000 Silica 32 Infinity Reflec- tor 31 Infinity Infinity 91.0000 Silica space 1.7156 34 Infinity Infinity 6.000 Silica space 23.3211 36 A(2) −23.3211 Reflec- tor 34 Infinity Infinity −6.000 Silica space −1.7156 31 Infinity Infinity −91.0000 Silica 31 Infinity Infinity −68.0000 Silica space −1.7156 38 Infinity Infinity −4.4503 Silica space −0.5000 40 −627.6194 CX 211.4176 CX −21.5127 CaF2 space −0.5000 42 −87.2228 CX −200.3029 CC −19.1435 CaF2 space −0.5000 44 −91.9856 CX −59.4578 CC −27.1671 Silica space −2.9551 46 −73.3403 CX −160.4650 CC −21.3988 CaF2 space −1.4194 48 −126.8033 CX −368.0257 CC −5.2755 CaF2 space −1.0000 49 Infinity Infinity −0.9000 Silica Image Distance = −2.3000 50 Infinity
and the aspheric constants A(1) and A(2) are provided according to the following equation and Table 1A
TABLE 1A z = ( curv ) ⁢ y 2 1 + ( 1 - ( 1 + K ) ⁢ ⁢ ( curv ) 2 ⁢ y 2 ) 1 / 2 + ⁢ ( A ) ⁢ y 4 + ⁢ ( B ) ⁢ y 6 + ⁢ ( C ) ⁢ y 8 + ⁢ ( D ) ⁢ y 10 + ⁢ ( E ) ⁢ y 12 + ⁢ ( F ) ⁢ y 14 + ( G ) ⁢ y 16 + ( H ) ⁢ y 18 + ( J ) ⁢ y 20 Aspheric Curv K A B C D A(1) 0.00497390 0.000000 2.35640E−08 −7.81654E−14 −4.40789E−17 2.12263E−20 A(2) −0.00289239 0.000000 2.36370E−09 1.65324E−13 7.69607E−18 9.96953E−23 E F G H J A(1) −6.05312E−24 9.94327E−28 −8.75026E−28 3.18657E−36 0.00000E+00 A(2) 4.61249E−26 −3.24220E−30 2.06573E−34 −4.86011E−40 0.00000E+00
whereby an image field is formed.

2 more elements

An optical reduction system comprising:

a construction substantially according to the following construction data in Table 2
TABLE 2 Element Radius of Radius of Thickness Number Curvature(Front)mm Curvature(Back)mm mm Glass 10 Infinite 71.0257 112 Infinity Infinity 6.0000 Silica space 6.0014 114 Infinity −1637.5100 CX 17.8788 Silica space 9.1702 116 −433.0968 CC 2598.0412 CC 29.3027 Silica space 28.9382 118 −5578.3482 CC −382.9273 CX 29.8579 Silica space 16.6017 120 −189.0676 CC −239.8621 CX 18.0000 Silica space 1.5014 122 259.603 CX −2163.768 CX 37.8249 Silica space 86.0743 124 Infinity −64.0738 Reflec- tor 126 −200.8102 CX −363.2248 CC −28.2406 Silica space −48.5160 128 A(1) 215.5519 CX −30.2428 Silica space −2.0011 130 −718.0642 CX −142.9228 CC −12.1060 Silica space −23.8197 131 Infinity Infinity −91.0000 Silica 132 Infinity Reflec- tor 131 Infinity Infinity 91.0000 Silica space 1.7156 134 Infinity Infinity 6.0000 Silica space 25.1737 136 A(2) −25.1737 Reflec- tor 134 Infinity Infinity −6.0000 Silica space −1.7156 131 Infinity Infinity −91.0000 Silica 131 Infinity Infinity −68.000 Silica space −1.7156 138 Infinity Infinity −4.4503 Silica space −0.5000 140 −366.1837 CX 259.6264 CX −22.6130 CaF2 space −0.5000 142 −85.8999 CX −176.3075 CC −19.0232 CaF2 space −0.5000 144 −86.4495 CX −64.6738 CC −15.3239 CaF2 space −5.5180 146 −100.7188 CX −180.9651 CC −31.1363 CaF2 space −1.2329 148 −138.0675 CX −502.9595 CC −5.2755 CaF2 space −1.0000 149 Infinity Infinity −0.9000 Silica Image Distance = −2.3000 50 Infinity
and the aspheric constants A(1) and A(2) are provided according to the following equation and Table 2A
TABLE 2A z = ( curv ) ⁢ y 2 1 + ( 1 - ( 1 + K ) ⁢ ⁢ ( curv ) 2 ⁢ y 2 ) 1 / 2 + ⁢ ( A ) ⁢ y 4 + ⁢ ( B ) ⁢ y 6 + ⁢ ( C ) ⁢ y 8 + ⁢ ( D ) ⁢ y 10 + ⁢ ( E ) ⁢ y 12 + ⁢ ( F ) ⁢ y 14 + ( G ) ⁢ y 16 + ( H ) ⁢ y 18 + ( J ) ⁢ y 20 Aspheric Curv K A B C D A(1) 0.00576125 0.000000 3.60293E−09 −4.18487E−13 −4.80164E−17 1.86225E−20 A(2) −0.00288476 0.000000 1.74269E−09 1.17255E−13 6.94898E−18 −2.48358E−22 E F G H J A(1) −5.22691E−24 8.72143E−28 −7.89947E−32 2.97093E−36 0.00000E+00 A(2) 7.10580E−26 −5.86680E−30 3.49595E−34 −6.83625E−39 0.00000E+00
whereby an image field is formed.

2 more elements

An optical reduction system comprising:

a construction substantially according to the following construction data in Table 3
TABLE 3 Element Radius of Radius of Thickness Number Curvature(Front)mm Curvature(Back)mm mm Glass 10 Infinite 71.0257 212 Infinite Infinite 6.0000 Silica space 5.9995 214 Infinite −1637.5100 CX 17.8788 Silica space 4.5575 216 −1237.3096 CC A(1) 19.5803 Silica space 7.4171 218 364.2097 CX −674.5230 CX 25.6054 Silica space 25.3077 220 −185.3015 CC −283.9553 CX 30.8746 Silica space 1.5004 222 332.0965 CX −480.2185 CX 42.1200 Silica 224 Infinite −64.0738 Reflec- tor 226 −197.3304 CX −362.9388 CC −30.0000 Silica space −38.3129 228 A(2) 303.6930 CX −30.2428 Silica space −2.0000 230 −686.9764 CX −140.3749 CC −19.1575 Silica space −25.2130 231 Infinite Infinite −91.000 Silica 232 Infinite Reflec- tor 231 Infinity Infinite 91.0000 Silica space 1.7156 234 Infinite Infinite 6.0000 Silica space 23.4104 236 A(3) −23.4104 Reflec- tor 234 Infinite Infinite −6.0000 Silica space −1.7156 231 Infinite Infinite −91.0000 Silica 231 Infinity Infinite −68.0000 Silica space −1.7156 238 Infinite Infinite −4.4503 Silica space −0.5000 240 −294.3870 CX 285.2516 CX −22.3559 CaF2 space −0.5000 242 −90.0227 CX −143.4682 CC −15.3841 CaF2 space −0.5000 244 −86.3937 CX A(4) −16.8094 CaF2 space −4.2386 246 −91.3982 CX A(5) −35.1077 CaF2 space −1.2404 248 −193.8008 CX −584.4706 CC −5.2755 CaF2 space −1.0000 249 Infinite Infinite −0.9000 Silica Image Distance = −2.3000 50 Infinite
and the aspheric constants A(1), A(2), A(3), A(4), and A(5) are provided according to the following equation and Table 3A
TABLE 3A z = ( curv ) ⁢ y 2 1 + ( 1 - ( 1 + K ) ⁢ ⁢ ( curv ) 2 ⁢ y 2 ) 1 / 2 + ⁢ ( A ) ⁢ y 4 + ⁢ ( B ) ⁢ y 6 + ⁢ ( C ) ⁢ y 8 + ⁢ ( D ) ⁢ y 10 + ⁢ ( E ) ⁢ y 12 + ⁢ ( F ) ⁢ y 14 + ( G ) ⁢ y 16 + ( H ) ⁢ y 18 + ( J ) ⁢ y 20 Aspheric Curv K A B C D A(1) 0.00383949 0.000000 −5.74812E−09 1.78952E−13 3.56502E−18 −4.29928E−22 A(2) 0.00408685 0.000000 3.46415E−09 −2.46236E−13 2.98339E−21 3.46678E−21 A(3) −0.00290152 0.000000 1.61839E−09 1.11129E−13 5.08685E−18 −5.96371E−23 A(4) −0.01476551 0.000000 6.79788E−08 2.28037E−11 4.76211E−15 2.35042E−18 A(5) −0.00407592 0.000000 −1.85475E−07 −5.95105E−11 2.46369E−14 −3.41676E−17 E F G H J A(1) 1.07476E−25 −7.13558E−30 0.00000E+00 0.00000E+00 0.00000E+00 A(2) −1.14760E−24 1.97684E−28 −1.74440E−32 6.27538E−37 0.00000E+00 A(3) 5.45877E−23 −5.30479E−30 3.27535E−34 −5.74203E−39 0.00000E+00 A(4) −3.36512E−22 2.71804E−25 0.00000E+00 0.00000E+00 0.00000E+00 A(5) 2.68515E−25 1.36619E−30 0.00000E+00 0.00000E+00 0.00000E+00
whereby an image field is formed.

2 more elements

An optical reduction system comprising:

a construction substantially according to the following construction data in Table 4
TABLE 4 Element Radius of Radius of Thickness Number Curvature(Front)mm Curvature(Back)mm mm Glass 10 Infinite 71.0257 312 Infinite Infinite 6.0000 CaF2 space 5.9971 314 Infinite −1637.5100 CX 17.8788 CaF2 space 6.8555 316 −601.0743 CC 337.2385 CC 19.3530 CaF2 space 39.1414 318 372.9672 CX −444.4615 CX 35.0514 CaF2 space 17.5760 320 −238.7418 CC −374.7892 CX 33.5080 CaF2 space 1.5026 322 271.2372 CX −2141.5952 41.9745 CaF2 space 85.7471 324 Infinite −64.0738 Reflec- tor 326 −218.7966 CX −378.3046 CC −30.0000 CaF2 space −41.2869 328 A(1) 331.4015 CX −30.2428 CaF2 space −2.0021 330 −473.0920 CX −138.9426 CC −15.0066 CaF2 space −25.4542 331 Infinite Infinite −91.9338 CaF2 332 Infinite Reflec- tor 331 Infinite Infinite 91.9338 CaF2 space 1.7156 334 Infinite Infinite 6.0000 CaF2 space 23.9891 326 A(2) −23.2891 Reflec- tor 334 Infinite Infinite −6.0000 CaF2 space −1.7156 331 Infinite Infinite −91.9336 CaF2 331 Infinite Infinite −68.0000 CaF2 space −1.7156 328 Infinite Infinite −4.4503 CaF2 space −0.5000 340 −379.1353 CX 304.9678 CX −21.8077 CaF2 space −0.5000 342 −94.2814 CX −162.6972 CC −17.3319 CaF2 space −1.0800 344 −115.8596 CX −73.3964 CC −20.5225 CaF2 space −3.8075 346 −92.2350 CX −218.2297 CC −42.4471 CaF2 space −1.1466 348 −155.2317 CX −656.3405 CC −5.2755 CaF2 space −1.0000 349 Infinite Infinite −0.9000 CaF2 Image Distance = −2.3000 50 Infinite
and the aspheric constants A(1) and A(2) are provided according to the following equation and Table 4A
TABLE 4A z = ( curv ) ⁢ y 2 1 + ( 1 - ( 1 + K ) ⁢ ⁢ ( curv ) 2 ⁢ y 2 ) 1 / 2 + ⁢ ( A ) ⁢ y 4 + ⁢ ( B ) ⁢ y 6 + ⁢ ( C ) ⁢ y 8 + ⁢ ( D ) ⁢ y 10 + ⁢ ( E ) ⁢ y 12 + ⁢ ( F ) ⁢ y 14 + ( G ) ⁢ y 16 + ( H ) ⁢ y 18 + ( J ) ⁢ y 20 Aspheric Curv K A B C D A(1) 0.00475685 0.000000 8.25386E−09 −1.36412E−13 −4.41072E−17 2.29567E−20 A(2) −0.00272498 0.000000 1.82601E−09 9.56998E−14 6.16098E−18 −4.25832E−22 E F G H J A(1) −6.72654E−24 1.13058E−27 −1.00992E−31 3.72128E−36 0.00000E+00 A(2) 8.51395E−26 −7.80032E−30 4.75429E−34 −1.14164E−38 0.00000E+00
whereby an image field is formed.

2 more elements

Dependencies are inferred from the claim text.

High numerical aperture catadioptric lens

Life of this patent

High numerical aperture catadioptric lens

Life of this patent

Abstract

Claims20