Inspection microscope for several wavelength ranges and reflection reducing layer for an inspection microscope for several wavelength ranges
View Patent ↗An inspection microscope for several wavelength ranges with at least one illuminating beam path and at least one imaging beam path. Those optical elements in the illuminating beam path and in the imaging beam path, through which beams of all wavelengths pass, are provided with a reflection-reducing layer, by means of which the wavelength ranges with reduced reflection are the visible VIS-wavelength range up to 650 nm, the i-lines at λ=365 nm and the ultraviolet DUV-wavelength range from 240 nm to 270 nm. The reflection-reducing layer is a sandwich structure, comprising various material combinations, such as for example, M2/MgF 2 or M2/MgF 2 /SiO 2 or M2/MgF 2 /Al 2 O 3 , where M2 is a mixed substance from the company Merck, comprising Al 2 O 3 . The optical components with reduced reflectance preferably comprise quartz glass or CaF 2 .
1. An inspection microscope for a plurality of wavelength regions comprising:
at least one illumination beam path and
at least one imaging beam path;
wherein optical components in the illumination beam path and in the imaging beam path through which beams of all wavelength regions pass are covered with a reflection-reducing layer,
wherein the reflection-reducing layer reduces an amount of reflection of light at specific reduced-reflection wavelength regions incident on the optical components relative to an amount of reflection of light at the reduced-reflection wavelength regions incident on the optical components without such a layer,
wherein the reduced-reflection wavelength regions are the visible (“VIS”) wavelength region up to approximately 650 nm, the i line at λ=365 nm and the deep ultraviolet (“DUV”) wavelength region from 240 nm to 270 nm,
wherein the reflection-reducing layer has a sandwich structure which comprises the materials:
M2,
and MgF 2 ;
wherein the sandwich structure comprises a plurality of layers of M2 and MgF 2 applied alternately and the final layer comprising MgF 2 ; and
wherein M2 is a mixed substance comprising La 2 O 3 .3.3 Al 2 O 3 .
2. An inspection microscope for a plurality of wavelength regions comprising:
at least one illumination beam path and
at least one imaging beam path;
wherein optical components in the illumination beam path and in the imaging beam path through which beams of all wavelength regions pass are covered with a reflection-reducing layer,
wherein the reflection-reducing layer reduces an amount of reflection of light at specific reduced-reflection wavelength regions incident on the optical components relative to an amount of reflection of light at the reduced-reflection wavelength regions incident on the optical components without such a layer,
wherein the reduced-reflection wavelength regions are the visible (“VIS”) wavelength region up to approximately 650 nm, the i line at λ=365 nm and the deep ultraviolet (“DUV”) wavelength region from 240 nm to 270 nm,
wherein the reflection-reducing layer has a sandwich structure which comprises the materials:
M2,
MgF 2 ,
and Al 2 O 3 ;
wherein the sandwich structure comprises a plurality of layers of Al 2 O 3 and MgF 2 being applied alternately in the lower part of the sandwich structure and a plurality of layers of M2 and MgF 2 being applied alternately in the upper part of the sandwich structure, and with the final layer comprising MgF 2 ; and
wherein M2 is a mixed substance comprising La 2 O 3 .3.3 Al 2 O 3 .
3. A reflection-reducing layer for a plurality of wavelength regions, wherein the reflection-reducing layer is configured to reduce an amount of reflection of light at specific reduced-reflection wavelength regions incident on optical components relative to an amount of reflection of light at the reduced-reflection wavelength regions incident on the optical components without such a layer, wherein the reduced-reflection wavelength regions are the visible (“VIS”) wavelength region up to approximately 650 nm, the i line at λ=365 nm and the deep ultraviolet (“DUV”) wavelength region at 240 to 270 nm,
wherein the reflection-reducing layer has a sandwich structure which comprises the materials:
M2,
and MgF 2 ;
wherein the sandwich structure comprises a plurality of layers of M2 and MgF 2 being applied alternately and the final layer comprising MgF 2 ; and
wherein M2 is a mixed substance comprising La 2 O 3 .3.3 Al 2 O 3 .
4. The reflection-reducing layer as claimed in claim 3 , wherein the reflection-reducing layer is designed for optical components made from quartz glass or from CaF 2 and has a structure corresponding to Table F below, where layer 1 is the bottom layer:
TABLE F
Approximate
Layer No.
Thickness in nm
Material
1
14.56
M2
2
15.38
MgF 2
3
19.55
M2
4
10.64
MgF 2
5
87.07
M2
6
22.38
MgF 2
7
21.89
M2
8
123.66
MgF 2
9
17.88
M2
10
26.19
MgF 2
11
68.93
M2
12
12.7
MgF 2
13
16.16
M2
14
66.19
MgF 2 .
5. The use of the reflection-reducing layer as claimed in claim 4 , wherein the reflection from optical components made from either quartz glass or CaF 2 is reduced by application of the reflection-reducing layer.
6. A reflection-reducing layer for a plurality of wavelength regions, wherein the reflection-reducing layer is configured to reduce an amount of reflection of light at specific reduced-reflection wavelength regions incident on optical components relative to an amount of reflection of light at the reduced-reflection wavelength regions incident on the optical components without such a layer, wherein the reduced-reflection wavelength regions are the visible (“VIS”) wavelength region up to approximately 650 nm, the i line at λ=365 nm and the deep ultraviolet (“DUV”) wavelength region at 240 to 270 nm,
wherein the reflection-reducing layer has a sandwich structure which comprises the materials:
M2,
MgF 2 ,
and Al 2 O 3 ;
wherein the sandwich structure comprises a plurality of layers comprising Al 2 O 3 and MgF 2 being applied alternately in the lower part of the sandwich structure and a plurality of layers comprising M2 and MgF 2 being applied alternately in the upper part of the sandwich structure, and with the final layer comprising MgF 2 ; and
wherein M2 is a mixed substance comprising La 2 O 3 .3.3 Al 2 O 3 .
7. The reflection-reducing layer as claimed in claim 6 , wherein the reflection-reducing layer has only a single layer of Al 2 O 3 .
8. The reflection-reducing layer as claimed in claim 6 , wherein the reflection-reducing layer is designed for optical components made from quartz glass or from CaF 2 and has a structure as shown in Table E below, with layer 1 being the bottom layer:
TABLE E
Approximate
Layer No.
Thickness in nm
Material
1
136.17
Al 2 O 3
2
175
MgF 2
3
24.26
M2
4
26.85
MgF 2
5
14.66
M2
6
77.29
MgF 2 .
9. An inspection microscope for a plurality of wavelength regions composing:
at least one illumination beam path and
at least one imaging beam path;
wherein optical components in the illumination beam path and in the imaging beam path through which beams of all wavelength regions pass are covered with a reflection-reducing layer,
wherein the reflection-reducing layer reduces an amount of reflection of light at specific reduced-reflection wavelength regions incident on the optical components relative to an amount of reflection of light at the reduced-reflection wavelength regions incident on the optical components without such a layer,
wherein the reduced-reflection wavelength regions are the visible (“VIS”) wavelength region up to approximately 650 nm, the i line at λ=365 nm and the deep ultraviolet (“DUV”) wavelength region from 240 nm to 270 nm, and
wherein the reflection-reducing layer has a sandwich structure which comprises La 2 O 3 .3.3 Al 2 O 3 and MgF 2 .
10. The inspection microscope as claimed in claim 9 , wherein the reflection-reducing layer has a sandwich structure which comprises the materials:
M2,
MgF 2 , and
SiO 2 ;
wherein the sandwich structure comprises a plurality of layers of M2 and SiO 2 being applied alternately in the lower part of the sandwich structure and a plurality of layers of M2 and MgF 2 being applied alternately in the upper part of the sandwich structure, and with the final layer comprising MgF 2 ; and
wherein M2 is a mixed substance comprising La 2 O 3 .3.3 Al 2 O 3 .
11. The inspection microscope as claimed in claim 10 , wherein at the reflection-reducing layer the mean reflection value for the VIS wavelength region and the i line is ≦1.0% and the mean reflection value for the DUV wavelength region is ≦0.5%.
12. The inspection microscope as claimed in claim 9 , wherein the optical components covered with the reflection-reducing layer comprise quartz glass or CaF 2 and have a uniform reflection-reducing layer.
13. The inspection microscope as claimed in claim 9 , wherein one or more component changers having at least two wavelength region-specific optical components for optionally introducing in each case at least one of these components into the illumination beam path and the imaging beam path are arranged in the associated beam path.
14. A reflection-reducing layer for a plurality of wavelength regions, wherein the reflection-reducing layer is configured to reduce an amount of reflection of light at specific reduced-reflection wavelength regions incident on optical components relative to an amount of reflection of light at the reduced-reflection wavelength regions incident on the optical components without such a layer, wherein the reduced-reflection wavelength regions are the visible (“VIS”) wavelength region up to approximately 650 nm, the i line at λ=365 nm and the deep ultraviolet (“DUV”) wavelength region at 240 to 270 nm, and wherein the reflection-reducing layer has a sandwich structure which comprises La 2 O 3 ·3.3 Al 2 O 3 and MgF 2 .
15. The reflection-reducing layer as claimed in claim 14 , wherein the reflection-reducing layer is designed for optical components made from quartz glass or from CaF 2 .
16. The reflection-reducing layer as claimed in claim 14 , wherein the reflection-reducing layer has a sandwich structure which comprises the materials:
M2,
MgF 2 ,
and SiO 2 ;
wherein the sandwich structure comprises a plurality of layers comprising M2 and SiO 2 being applied alternately in the lower part of the sandwich structure and a plurality of layers comprising M2 and MgF 2 being applied alternately in the upper part of the sandwich structure, and with the final layer comprising MgF 2 ; and
wherein M2 is a mixed substance comprising La 2 O 3 .3.3 Al 2 O 3 .
17. The reflection-reducing layer as claimed in claim 16 , wherein the reflection-reducing layer has at least three layers of SiO 2 and at least three layers of MgF 2 .
18. The reflection-reducing layer as claimed in claim 16 , wherein the mean reflection value for the VIS wavelength region and the i line is ≦1.0% and the mean reflection value for the DUV wavelength region is ≦0.5%.
19. The reflection-reducing layer as claimed in claim 18 , wherein the reflection-reducing layer is designed for optical components made from quartz glass or from CaF 2 and has a structure corresponding to Table A below, where layer 1 is the bottom layer:
TABLE A
Approximate
Layer No.
Thickness in nm
Material
1
14.9
M2
2
25.57
SiO 2
3
20.72
M2
4
10.12
SiO 2
5
66.94
M2
6
9.17
SiO 2
7
6.07
M2
8
14.44
SiO 2
9
21.87
M2
10
110.66
SiO 2
11
21.78
M2
12
20.16
MgF 2
13
70.39
M2
14
14.05
MgF 2
15
15.58
M2
16
66.86
MgF 2 .
20. The reflection-reducing layer as claimed in claim 18 , wherein the reflection-reducing layer is designed for optical components made from quartz glass or from CaF 2 and has a structure as given in Table B below, where layer 1 is the bottom layer:
TABLE B
Approximate
Layer No.
Thickness in nm
Material
1
13.95
M2
2
27.60
SiO 2
3
20.66
M2
4
8.84
SiO 2
5
69.42
M2
6
20.90
SiO 2
7
24.61
M2
8
112.60
SiO 2
9
21.02
M2
10
20.60
MgF 2
11
69.85
M2
12
13.97
MgF 2
13
16.01
M2
14
66.65
MgF 2 .
21. The reflection-reducing layer as claimed in claim 16 , wherein the reflection-reducing layer is designed for optical components made from quartz glass or from CaF 2 and has a structure as given in Table C below, where layer 1 is the bottom layer:
TABLE C
Approximate
Layer No.
Thickness in nm
Material
1
15.71
M2
2
21.57
SiO 2
3
96.82
M2
4
20.75
SiO 2
5
25.35
M2
6
114.91
SiO 2
7
19.29
M2
8
20.47
MgF 2
9
67.52
M2
10
14.19
MgF 2
11
17.22
M2
12
65.82
MgF 2 .
22. The reflection-reducing layer as claimed in claim 16 , wherein the reflection-reducing layer is designed for optical components made from quartz glass or from CaF 2 and has a structure as given in Table D below, where layer 1 is the bottom layer:
TABLE D
Approximate
Layer No.
Thickness in nm
Material
1
7.08
M2
2
28.54
SiO 2
3
18.90
M2
4
11.79
SiO 2
5
99.82
M2
6
15.97
SiO 2
7
15.98
M2
8
126.92
SiO 2
9
19.24
M2
10
12.55
MgF 2
11
63.48
M2
12
8.65
MgF 2
13
25.04
M2
14
65.56
MgF 2 .