CN100480772C - Refraction-reflection type projection optical system - Google Patents
Refraction-reflection type projection optical system Download PDFInfo
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- CN100480772C CN100480772C CNB2007101719661A CN200710171966A CN100480772C CN 100480772 C CN100480772 C CN 100480772C CN B2007101719661 A CNB2007101719661 A CN B2007101719661A CN 200710171966 A CN200710171966 A CN 200710171966A CN 100480772 C CN100480772 C CN 100480772C
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Abstract
The invention discloses a catadioptric projection optical system. The invention can apply the full view field of the optical system design, which avoids the half utilization efficiency of the view field and improves the manufacture efficiency of the product. The catadioptric projection optical system applies two spherical reflectors and a plane reflector (with light blocking function); the invention avoids the utilization of polarization beam splitter with a large size and the application of 1/4 polarization beam splitting film within the deep ultraviolet range; the invention reduces the manufacture difficulty; the catadioptric projection optical system avoids the utilization of reflector with super size and reduces the manufacture and assembly difficulty of the spherical reflector with super size.
Description
Technical field
The present invention relates to a kind of optical system, relate in particular to a kind of refraction-reflection type projection optical system.
Background technology
Photoetching is a very important procedure in the semiconductor fabrication process, employed exposure device in the photo-mask process, by projection optical system the graphic pattern projection of mask is exposed on the photonasty substrate as wafer etc. again, the quality of exposure quality will have very big influence to follow-up etching procedure.Along with the raising of semiconductor element integrated level, semiconductor fabrication process also increases to the requirement of projection optical system resolution.In order to satisfy the requirement to projection optical system resolution, exposure device need shorten the wavelength of illumination light (exposure light), perhaps improves the picture number formulary value aperture (NA) of projection optical system.
Patent US 6,496, and 306 B1 and patent US 6,195, the described two kinds of refraction-reflection type projection optical systems of 213B1 can actual visual field of using only have half of optical design, and the reduction of exposure visual field will influence productive rate.
The described a kind of refraction and reflection projection optical system of patent US 2002/0167737 A1 has used bigger polarization splitting prism, increase along with projection objective numerical aperture and visual field, cause the size of polarization splitting prism to become increasing, make the difficulty of processing of polarization splitting prism strengthen; And in the deep UV (ultraviolet light) spectral limit, it is extremely difficult that the realization of 1/4 polarization beam splitter also becomes.
Patent US 6,169, and the described a kind of refraction-reflection type projection optical system of 627 B1 has used the catoptron of two oversizes, and the difficulty of the oversize catoptron of realization high-precision processing demand is bigger, and the assembly difficulty of oversize catoptron is also bigger.
This patent is the practical problems that runs into for fear of above-mentioned patent, and a kind of refraction-reflection type projection optical system of invention.
Summary of the invention
The object of the present invention is to provide a kind of refraction-reflection type projection optical system,, shorten the wavelength of illumination light (exposure light), the picture number formulary value aperture (NA) of improving projection optical system to satisfy requirement to projection optical system resolution.
In order to achieve the above object, the invention provides a kind of refraction-reflection type projection optical system, comprise first lens combination formed by first lens combination and second lens combination, be plane mirror that 45 degree are provided with the incident primary optical axis, reflective concave surface is towards described plane mirror and be in spherical reflector one and the spherical reflector two that the right angle is provided with, and the 3rd lens combination; After imaging passes this first lens combination, the back side of this plane mirror of directive; This imaging part is absorbed by this plane mirror, this spherical reflector one of unabsorbed part directive; This spherical reflector one catoptric imaging light is to the reflecting surface of this plane mirror; The reflecting surface of this plane mirror reflexes to this spherical reflector two with this imaging; This imaging is through these spherical reflector two reflections, and a part is blocked by this plane mirror, and the part that is not blocked enters the 3rd lens combination in the image planes imaging.
Space length between this first lens combination and second lens combination need be greater than 1.5 times of this imaging size that incides described second lens combination.Use catoptron turnover light path to satisfy, make object plane and image planes keeping parallelism, be convenient to the control of mask platform and work stage synchronization accuracy in this space.
Spend less than 5 from the beam angle of this second lens combination outgoing, be convenient to the size of about light beams on plane mirror.
This plane mirror block the light zone less than 30% of this imaging of incident.
A surface of this plane mirror is coated with highly reflecting films, another surperficial coating ahsorption membrane.
The material substrate of this plane mirror is the material of low thermal coefficient of expansion, and the material of this low thermal coefficient of expansion can be SiO
2
The 3rd lens combination group can be the plane near the lens surface of image planes, is convenient to be applied to the leveling and focusing technology in the exposure process.
When this refraction-reflection type projection optical system is applied to greater than 0.75 numerical aperture, spherical reflector one and spherical reflector two can be replaced with non-spherical reflector, to reach the image quality that better arrives.
These image planes and the 3rd lens combination are near can the filling liquid medium between the eyeglass of image planes, to increase the picture number formulary value aperture (〉 1.0 of this refraction-reflection type projection optical system) thus raising resolution.
This imaging can use the spectrum of ultraviolet band, and the spectrum of this ultraviolet band can be 365nm, and can be 248nm, can be 193nm, can also be 157nm.
This plane mirror can use different size to replace.
Refraction-reflection type projection optical system of the present invention, the available rate of a half field-of-view is avoided only having in the full visual field that can use design of Optical System, has improved the productive rate of product; This refraction-reflection type projection optical system has used two spherical reflectors and a plane side to penetrate mirror (having the light of blocking function), avoid using the polarization splitting prism of large-size, avoid using 1/4 polarization beam splitter in the deep UV (ultraviolet light) spectral limit simultaneously, reduced manufacture difficulty; This refraction-reflection type projection optical system avoids using the catoptron of oversize, has reduced the processing and the assembly difficulty of oversize spherical reflector.
Description of drawings
Fig. 1 is a refraction-reflection type projection optical system optical principle synoptic diagram of the present invention;
Fig. 2 is a refraction-reflection type projection optical system optical texture synoptic diagram of the present invention.
In the accompanying drawing: 1, object; 2, optical system; 21, first lens combination; 211, first lens combination; 212, second lens combination; 22, mirror group; 221, spherical reflector one; 222, spherical reflector two; 223, plane mirror; 23, the 3rd lens combination; 3, as.
Embodiment
Below in conjunction with accompanying drawing the specific embodiment of the present invention is further described.
Accompanying drawing 1 shows refraction-reflection type projection optical system optical principle synoptic diagram of the present invention, object 1 obtains as 3 by optical system 2 imagings, wherein optical system 2 comprises first lens combination 21, mirror group 22 and 23 3 part compositions of the 3rd lens combination, mirror group 22 is made up of two spherical reflectors and a plane mirror, and this plane mirror has the light of blocking function in optical system.
First lens combination comprises first lens combination 211 and second lens combination 212.First lens combination 211 comprises eyeglass L1, and eyeglass L1 is a positive lens; Second lens combination 212 comprises eyeglass L2-L7, and eyeglass L2 is that positive lens, eyeglass L3 are that convex surface is that concave surface is that convex surface is that positive lens, eyeglass L7 are positive lenss towards diverging meniscus lens, the eyeglass L6 of object plane towards diverging meniscus lens, the eyeglass L5 of object plane towards diverging meniscus lens, the eyeglass L4 of object plane.Space length in first lens combination 21 between first lens combination 211 and second lens combination 212 need satisfy the distance that incides second lens combination, 212 beam sizes sizes greater than 1.5 times, to satisfy in this space use catoptron turnover light path, make object plane and image planes keeping parallelism, be convenient to the control of mask platform and work stage synchronization accuracy; Need be convenient to the size of about light beams on plane mirror 223 less than 5 degree from the angle of the parallel beam of second lens combination, 212 outgoing.
Comprise in the mirror group 22 that spherical reflector one 221 reflective concave surface are towards object plane, spherical reflector 2 222 reflective concave surface become 45 degree to place towards image planes and plane mirror 223 with the incident primary optical axis, light beam is after 212 outgoing of second lens combination, at first pass through plane mirror 223, light beam in plane mirror 223 range of size is blocked, beam Propagation outside the range of size is to spherical reflector 1, shine through spherical reflector one 221 beam reflected on the effective dimensions of plane mirror 223 and reflex on the spherical reflector 2 222, reflex to mirror group the 3rd lens combination 23 once more by spherical reflector 2 222.Wherein the size of plane mirror 223 need satisfy: block the light zone should less than total incident beam 30% in.A surface of plane mirror 223 needs the plating highly reflecting films, another surperficial coating ahsorption membrane, and material substrate need be the material such as the SiO of low thermal coefficient of expansion
2Deng.
The 3rd lens combination 23 comprises eyeglass L8-L12, and eyeglass L8 and L9 are that positive lens, eyeglass L10 and L11 are that concave surface is positive lenss towards positive lens, the eyeglass L12 of image planes.The 3rd lens combination 23 will be imaged onto image planes from the light beam of spherical reflector 2 222 incidents, be the plane near the lens surface of image planes wherein, be convenient to be applied to the leveling and focusing technology in the exposure process.
In another embodiment of the present invention, this refraction-reflection type projection optical system is applied to greater than 0.75, for example during 0.93 numerical aperture, two spherical reflectors 221 and 222 can be replaced with two non-spherical reflectors, can reach better image quality.
In another embodiment of the present invention, also can in the image planes of this refraction-reflection type projection optical system and near filling liquid medium between the eyeglass L12 surface of image planes, for example: refractive index be 1.437, corresponding wavelength is the ultrapure water of 193nm.Increase to 1.30 as number formulary value aperture from 0.93 by what the filling liquid medium can make this refraction-reflection type projection optical system, thereby improve resolution.
In another embodiment of the present invention, the size of the plane mirror that uses in this refraction-reflection type projection optical system can be selected the specific plane mirror that blocks the light size according to the actual user demand of litho machine, as blocks light and be of a size of 20%, 15% and 10%.
In another embodiment of the present invention, this refraction-reflection type projection optical system uses the spectrum of 365nm, 248nm, 193nm and 157nm wave band respectively.
Claims (12)
1, a kind of refraction-reflection type projection optical system is characterized in that: described refraction-reflection type projection optical system comprises:
First lens combination of forming by first lens combination and second lens combination;
Be the plane mirror that 45 degree are provided with the incident primary optical axis;
Reflective concave surface is towards described plane mirror and be in spherical reflector one and the spherical reflector two that the right angle is provided with; And
The 3rd lens combination;
After imaging passes described first lens combination, the back side of the described plane mirror of directive; A described imaging part is absorbed by described plane mirror, the described spherical reflector one of unabsorbed part directive; Described spherical reflector one catoptric imaging light is to the reflecting surface of described plane mirror; The reflecting surface of described plane mirror reflexes to described spherical reflector two with described imaging; Described imaging is through described spherical reflector two reflections, and a part is blocked by described plane mirror, and the part that is not blocked enters described the 3rd lens combination in the image planes imaging.
2, refraction-reflection type projection optical system according to claim 1 is characterized in that: the space length between described first lens combination and second lens combination need be greater than 1.5 times of the described imaging size that incides described second lens combination.
3, refraction-reflection type projection optical system according to claim 1 is characterized in that: spend less than 5 from the beam angle of the described second lens combination outgoing.
4, refraction-reflection type projection optical system according to claim 1 is characterized in that: described plane mirror block the light zone less than 30% of the described imaging of incident.
5, refraction-reflection type projection optical system according to claim 1 is characterized in that: a surface of described plane mirror is coated with highly reflecting films, another surperficial coating ahsorption membrane.
6, refraction-reflection type projection optical system according to claim 1 is characterized in that: the material substrate of described plane mirror is the material of low thermal coefficient of expansion.
7, refraction-reflection type projection optical system according to claim 6 is characterized in that: the material of described low thermal coefficient of expansion is SiO
2
8, refraction-reflection type projection optical system according to claim 1 is characterized in that: described the 3rd lens combination is the plane near the lens surface of image planes.
9, refraction-reflection type projection optical system according to claim 1 is characterized in that: when described refraction-reflection type projection optical system is applied to greater than 0.75 numerical aperture, spherical reflector one and spherical reflector two are replaced with non-spherical reflector.
10, refraction-reflection type projection optical system according to claim 1 is characterized in that: described image planes and described the 3rd lens combination are near filling liquid medium between the eyeglass of image planes.
11, refraction-reflection type projection optical system according to claim 1 is characterized in that: described imaging uses the spectrum of ultraviolet band, and the spectrum of described ultraviolet band is 365nm, 248nm, 193nm or 157nm.
12, refraction-reflection type projection optical system according to claim 1 is characterized in that: described plane mirror uses different size to replace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007101719661A CN100480772C (en) | 2007-12-07 | 2007-12-07 | Refraction-reflection type projection optical system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007101719661A CN100480772C (en) | 2007-12-07 | 2007-12-07 | Refraction-reflection type projection optical system |
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| Publication Number | Publication Date |
|---|---|
| CN101201451A CN101201451A (en) | 2008-06-18 |
| CN100480772C true CN100480772C (en) | 2009-04-22 |
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| CNB2007101719661A Active CN100480772C (en) | 2007-12-07 | 2007-12-07 | Refraction-reflection type projection optical system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102012201075A1 (en) | 2012-01-25 | 2013-07-25 | Carl Zeiss Smt Gmbh | Optical assembly, EUV lithography apparatus and method of configuring an optical assembly |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0964307A2 (en) * | 1998-06-08 | 1999-12-15 | Nikon Corporation | Projection exposure apparatus and method |
| CN1637464A (en) * | 2003-12-23 | 2005-07-13 | 三星电子株式会社 | Projection lens unit and projection system employing the same |
| CN1851526A (en) * | 2006-06-02 | 2006-10-25 | 上海微电子装备有限公司 | Projection objective lens optical system |
-
2007
- 2007-12-07 CN CNB2007101719661A patent/CN100480772C/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0964307A2 (en) * | 1998-06-08 | 1999-12-15 | Nikon Corporation | Projection exposure apparatus and method |
| CN1637464A (en) * | 2003-12-23 | 2005-07-13 | 三星电子株式会社 | Projection lens unit and projection system employing the same |
| CN1851526A (en) * | 2006-06-02 | 2006-10-25 | 上海微电子装备有限公司 | Projection objective lens optical system |
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| Publication number | Publication date |
|---|---|
| CN101201451A (en) | 2008-06-18 |
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Address after: 201203 Zhangjiang High Tech Park, Shanghai, Zhang Dong Road, No. 1525 Patentee after: Shanghai microelectronics equipment (Group) Limited by Share Ltd Address before: 201203 Zhangjiang High Tech Park, Shanghai, Zhang Dong Road, No. 1525 Patentee before: Shanghai Micro Electronics Equipment Co., Ltd. |