CN102981249B - Projection optical system - Google Patents
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- CN102981249B CN102981249B CN201210360715.9A CN201210360715A CN102981249B CN 102981249 B CN102981249 B CN 102981249B CN 201210360715 A CN201210360715 A CN 201210360715A CN 102981249 B CN102981249 B CN 102981249B
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Abstract
The invention provides a projection optical system. A first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group are sequentially arranged along the direction of an optical axis of the projection optical system and located on the same optical axis. The first lens group and the third lens group are provided with negative focal power. The second lens group, the fourth lens group and the fifth lens group are provided with positive focal power. The first lens group receives input light beams and outputs first divergent beams; the second lens group receives the first divergent beams and output second divergent beams; the third lens group receives the second divergent beam and output first convergent beams; the fourth lens group receives the first convergent beams and outputs third divergent beams; and the fifth lens group receives the third divergent beams, outputs second convergent beams, and converges the second convergent beams to an image surface. On the condition of high resolutions and high numerical apertures, the projection optical system effectively reduces the number of lenses, reduces cost of processing, detecting and adjusting, and provides relatively large object space and image space working distances at the same time.
Description
Technical field
The present invention relates to the projection optical system in etching system, particularly relate to a kind of high-resolution projection optical system.
Background technology
Since the seventies, integrated circuit (IC) was come out, experienced by from a small scale to ultra-large developing stage, its progressive develop rapidly having benefited from photoetching.Photoetching is one of most important operation during large scale integrated circuit manufactures, the exposure sources used in photoetching, exposed to the silicon chip scribbling photoresist by figure accurate projection on mask with Step-and-repeat or scan mode by projection optical system, the quality of exposure quality is very large on follow-up development, etching, degumming process impact.Along with the development of IC manufacturing, also more and more higher to the resolution requirement of projection optical system.According to Rayleigh rule, resolution expression formula is as follows:
R＝k
1λ/NA
In above formula, R represents the resolution of litho machine, k
1represent process factor, λ represents the operation wavelength of projection optical system, and NA represents the numerical aperture of projection optical system.So, in order to improve resolution, need the wavelength of light source to be shortened or the numerical aperture of projection optical system is increased.In in the past more than 30 year, projection optical system wavelength has shortened to 365nm (i line) from 436nm (g line) and then has turned to the 248nm (KrF excimer laser) of deep ultraviolet wave band, 193nm (ArF excimer laser).Numerical aperture increases gradually by initial 0.3, but the various aberrations adopting the projection optical system of large-numerical aperture that more eyeglass must be used to carry out corrective system all control to obtain wave aberration RMS and to distort the projection optical system that the high picture element in 1nm requires.In US Patent No. 6349005B1, the operation wavelength of the projection optical system described in embodiment 3 is 248.38nm, is made up of 31 eyeglasses, but wave aberration RMS is larger with distortion.Wave aberration RMS is about 13m λ, i.e. 3.2nm, and distortion is about 3nm.Numerical aperture is only 0.7.In another patent US6522484B1 of the U.S., the operation wavelength of the projection optical system described in embodiment 6 is 193nm, is made up of 31 eyeglasses, but distortion is still comparatively large, is about 2nm.Numerical aperture is only 0.7.In two above-mentioned patents, although the number of lenses of projection optical system has all exceeded 30, wave aberration RMS and distortion are still comparatively large, do not meet the demands; Meanwhile, number of lenses is too many, and processing, detect and debug cost also and then increases.Further, the numerical aperture of two projection optical systems all only has 0.7.In addition, projection optical system in patent US6522484B1 described in embodiment 6, object space working distance and image space working distance are only 13mm, 12mm, object space working distance and image space working distance too short, bring very large difficulty to the positioning control of the design of mask and silicon slice workpiece platform and processing, mask and silicon chip.
Summary of the invention
In order to solve projection optical system number of lenses in prior art too much, wave aberration RMS with distortion is comparatively large, numerical aperture is less, object space working distance and the too short problem of image space working distance, the object of the present invention is to provide that a kind of number of lenses is less, wave aberration RMS and the projection optical system that distortion is less, numerical aperture is larger.In addition, this projection optical system can also provide larger object space and image space working distance, and this greatly reduces the design of mask and silicon slice workpiece platform and the positioning control difficulty of difficulty of processing, mask and silicon chip, and this projection optical system can also provide high resolving power.
For achieving the above object, the invention provides a kind of projection optical system, for by the pattern projection in object plane to picture plane, the first lens combination is mounted with along projection optical system optical axis direction, second lens combination, 3rd lens combination, 4th lens combination and the 5th lens combination, and the first lens combination, second lens combination, 3rd lens combination, 4th lens combination and the 5th lens combination are in same optical axis, from light beam incident direction order the first lens combination, there is negative power, second lens combination has positive light coke, 3rd lens combination has negative power, 4th lens combination has positive light coke and the 5th lens combination has positive light coke, wherein: the first lens combination, receive input beam, the light beam that object plane sends is dispersed, obtain and export the first divergent beams, second lens combination, receives the first divergent beams, assembles the first divergent beams, obtains and exports the second divergent beams, 3rd lens combination, receives the second divergent beams, disperses the second divergent beams, obtains and exports the 3rd divergent beams, 4th lens combination, receives the 3rd divergent beams, assembles, obtain and export the 4th divergent beams the 3rd divergent beams, 5th lens combination, receives the 4th divergent beams, assembles, obtain the first convergent beam, and the first convergent beam is converged to image planes to the 4th divergent beams.
The technique scheme that the present invention adopts compared with prior art, has following advantage:
1, five lens combination G1 to G5 of projection optical system of the present invention only adopt 20 a slice lens, but the wave aberration RMS of projection optical system has been reduced to 0.8nm, and the distortion of projection optical system has been reduced to 0.6nm.
2, numerical aperture of the present invention is larger, can reach 0.75.
3, projection optical system object space of the present invention and image space working distance increase 68mm, 18mm respectively, provide larger degree of freedom, reduce the positioning control difficulty of mask and silicon chip to the design of mask and silicon slice workpiece platform and processing.
4, projection optical system of the present invention, have employed three aspheric surfaces, and all control the high imaging quality requirement in 1nm with the wave aberration RMS and distortion that meet projection optical system, structure of the present invention greatly reduces the quantity of eyeglass, and system does not have cemented component.Therefore whole system structure is simple, reduces processing, detects, debugs cost.
5, in projection optical system of the present invention, all lens only use commaterial, reduce processing, testing cost.
Accompanying drawing explanation
Fig. 1 is the structural representation of projection optical system of the present invention;
Fig. 2 a, Fig. 2 b are projection optical system optical-modulation transfer function schematic diagram within the scope of full filed;
Fig. 3 is projection optical system astigmatism, the curvature of field and distortion schematic diagram;
Fig. 4 is the lines profile after development;
Fig. 5 is the process window of system.
Part description in figure:
1-first positive lens, 2-first meniscus lens,
3-first negative lens, 4-second negative lens,
5-the 3rd negative lens, 6-second positive lens,
7-the 3rd positive lens, 8-the 4th positive lens,
9-the 4th negative lens, 10-the 5th negative lens,
11-the 6th negative lens, 12-second meniscus lens,
13-the 7th negative lens, 14-the 5th positive lens,
15-the 3rd meniscus lens, 16-the 6th positive lens,
17-the 7th positive lens, 18-the 8th positive lens,
19-the 8th negative lens, 20-the 4th meniscus lens,
21-the 9th positive lens.
Embodiment
In order to better objects and advantages of the present invention are described, below in conjunction with accompanying drawing, the specific embodiment of the present invention is further described.
Fig. 1 is projection optical system structural representation of the present invention, projection optical system for by the pattern projection in object plane to picture plane, the first lens combination G1 is mounted with along projection optical system optical axis direction, second lens combination G2, 3rd lens combination G3, 4th lens combination G4 and the 5th lens combination G5, and the first lens combination G1, second lens combination G2, 3rd lens combination G3, 4th lens combination G4 and the 5th lens combination are in same optical axis, from light beam incident direction order the first lens combination G1, there is negative power, second lens combination G2 has positive light coke, 3rd lens combination G3 has negative power, 4th lens combination G4 has positive light coke and the 5th lens combination G5 has positive light coke, wherein: the first lens combination G1, receive input beam, the light beam that object plane sends is dispersed, obtain and export the first divergent beams, second lens combination G2, receives the first divergent beams, assembles the first divergent beams, obtains and exports the second divergent beams, 3rd lens combination G3, receives the second divergent beams, disperses the second divergent beams, obtains and exports the 3rd divergent beams, 4th lens combination G4, receives the 3rd divergent beams, assembles, obtain and export the 4th divergent beams the 3rd divergent beams, 5th lens combination G5, receives the 4th divergent beams, assembles, obtain the first convergent beam, and the first convergent beam is converged to image planes to the 4th divergent beams.
In above-mentioned projection optical system, lens combination G1 to G5 uses 21 lens altogether, described 21 lens comprise the first positive lens 1, first meniscus lens 2, first negative lens 3, second negative lens 4, 3rd negative lens 5, second positive lens 6, 3rd positive lens 7, 4th positive lens 8, 4th negative lens 9, 5th negative lens 10, 6th negative lens 11, second meniscus lens 12, 7th negative lens 13, 5th positive lens 14, 3rd meniscus lens 15, 6th positive lens 16, 7th positive lens 17, 8th positive lens 18, 8th negative lens 19, 4th meniscus lens 20, 9th positive lens 21.
In above-mentioned projection optical system, the first lens combination G1 comprises the first positive lens 1, first meniscus lens 2, first negative lens 3 and the second negative lens 4; The exit facet of the first meniscus lens 2 is the first aspheric surface, utilizes the astigmatism of the first Aspherical corrector projection optical system, coma, distortion.The light beam that object plane sends is successively through the first positive lens 1, first meniscus lens 2, first negative lens 3, second negative lens 4, for generating the first divergent beams, and exporting the first divergent beams by the second negative lens 4, described first divergent beams width is greater than the width of the light beam that object plane sends.In first lens combination G1, the clear aperture of the second negative lens 4 is maximum, reaches 153.4mm.
In above-mentioned projection optical system, the second lens combination G2 comprises the 3rd negative lens 5, second positive lens 6; Through the first divergent beams of the second negative lens 4 outgoing successively through the two or three negative lens 5, second positive lens 6, for generating the second divergent beams, and exporting the second divergent beams by the second positive lens 6, described second divergent beams width is greater than the width of the first divergent beams.In second lens combination G2, the clear aperture of the second positive lens 6 is maximum, reaches 255.6mm.
In above-mentioned projection optical system, the 3rd lens combination G3 comprises the 3rd positive lens 7, the 4th positive lens 8, the 4th negative lens 9, the 5th negative lens 10; Through the second divergent beams of the second positive lens 6 outgoing successively through the 3rd positive lens 7, the 4th positive lens 8, the 4th negative lens 9, the 5th negative lens 10, for generating the 3rd divergent beams, and exporting the 3rd divergent beams by the 5th negative lens 10, the 3rd divergent beams width is less than the width of the second divergent beams.In 3rd lens combination G3, the clear aperture of the 5th negative lens 10 is minimum, reaches 119mm.
In above-mentioned projection optical system, 4th lens combination G4 comprises the 6th negative lens 11, second meniscus lens 12, the 7th negative lens 13, the 5th positive lens 14, through the 3rd divergent beams of the 5th negative lens 10 outgoing successively through the 6th negative lens 11, second meniscus lens 12, the 7th negative lens 13, the 5th positive lens 14, for generating the 4th divergent beams, and export the 4th divergent beams by the 5th positive lens 14; Described 4th divergent beams width is greater than the width of the 3rd divergent beams.In 4th lens combination G4, the clear aperture of the 5th positive lens 14 is maximum, reaches 234.8mm.
In above-mentioned projection optical system, described 5th lens combination G5 comprises the 3rd meniscus lens 15, the 6th positive lens 16, the 7th positive lens 17, the 8th positive lens 18, the 8th negative lens 19, the 4th meniscus lens 20, the 9th positive lens 21; The plane of incidence of the 8th positive lens 18 is the second aspheric surface, utilizes the spherical aberration of the second Aspherical corrector projection optical system, coma, hereby all curvature of field; The exit facet of the 8th negative lens 19 is the 3rd aspheric surface, utilizes spherical aberration, coma, the astigmatism of the 3rd Aspherical corrector projection optical system; Through the 4th divergent beams of the 5th positive lens 14 outgoing successively through the 3rd meniscus lens 15, the 6th positive lens 16, the 7th positive lens 17, the 8th positive lens 18, the 8th negative lens 19, the 4th meniscus lens 20, for generating the first convergent beam, and export the first convergent beam by the 4th meniscus lens 20, first convergent beam outputs in image planes by the 9th positive lens 21, and described first convergent beam width is less than the width of the 4th divergent beams.In 5th lens combination G5, the clear aperture of the 9th lens 21 is minimum, reaches 97mm.
Five lens combination G1 to G5 in above-mentioned projection optical system adopt 21 eyeglasses altogether, and each eyeglass is all refraction type eyeglass, does not have reflective eyeglass.Adopt all-refraction type eyeglass reduce projection optical system processing, detect, debug cost.
In above-mentioned projection optical system, aperture diaphragm is set between the 5th positive lens 14 and the 3rd meniscus lens 15.The numerical aperture of described projection optical system is 0.75.
The optical material that first lens combination G1, the second lens combination G2, the 3rd lens combination G3, the 4th lens combination G4 and the 5th lens combination G5 adopt refractive index to be greater than 1.5 is respectively made, described optical material is the one in fused quartz, calcium fluoride, barium fluoride, or the one combination in fused quartz and calcium fluoride, fused quartz and barium fluoride, calcium fluoride and barium fluoride, fused quartz and calcium fluoride and barium fluoride.
The course of work of projection optical system embodiment of the present invention is: thing and mask are put in 68mm place before the first positive lens 1 of objective system, each field of view center light vertical incidence first positive lens 1, light enters the second lens combination G2 after the first lens combination G1 disperses, second lens combination G2 assembles light, obtains and exports divergent beams.Divergent beams are after the 3rd lens combination G3 disperses, and now the clear aperture of optical system reaches minimum.Light beam after dispersing assembles the aperture diaphragm place of arrival system through the 4th lens combination G4, and divergent beams, through the 5th lens combination G5 Refractive focusing, reduce four times and are imaged on the image planes after the 9th positive lens 21 and silicon chip.This projection optical system is object space and image space double telecentric structure.
In order to improve resolution, projection optical system of the present invention adopt operation wavelength be the ArF excimer laser of 193.4nm as light source, numerical aperture is 0.75.In order to reduce the positioning control difficulty of the design of mask and silicon slice workpiece platform and processing, mask and silicon chip, object space and image space working distance are increased to 68mm and 18mm respectively.
In order to reduce processing, detecting, debug cost, meet again large-numerical aperture, wave aberration RMS and distortion simultaneously and all control the high picture element requirement in 1nm, the all lens of projection optical system of the present invention are all in same optical axis, only be made up of 20 a slice lens, have employed three containing aspheric lens.First aspheric surface is positioned at the exit facet of the first meniscus lens 2, utilizes the astigmatism of the first Aspherical corrector projection optical system, coma, distortion.Second aspheric surface is positioned at the plane of incidence of the 8th positive lens 18, utilizes the spherical aberration of the second Aspherical corrector projection optical system, coma, hereby all curvature of field.3rd aspheric surface is positioned at the exit facet of the 8th negative lens 19, utilizes spherical aberration, coma, the astigmatism of the 3rd Aspherical corrector projection optical system.Certainly, aspheric position and variable amounts change, but the first lens combination G1 of projection optical system or the second lens combination G2 has 1 aspheric surface at least, and the 5th lens combination G5 has 1 aspheric surface at least.Because only have and adopt this structure, guarantee projection optical system had both met the large-numerical aperture demand that numerical aperture is 0.75, wave aberration RMS and the high picture element requirement all controlled within 1nm that distorts were met again.Such as, described aspheric quantity can also be four aspheric surfaces, aspheric position is the plane of incidence that the first aspheric surface is positioned at the first meniscus lens 2, second aspheric surface is positioned at the exit facet of the second positive lens 6,3rd aspheric surface is positioned at the exit facet of the 3rd meniscus lens 15, and the 4th aspheric surface is positioned at the plane of incidence of the 7th positive lens 17.
In order to easily manufactured and reduction processing, testing cost, in described projection optical system, all lens all use fused quartz (refractive index is 1.5602) as lens material.Certainly, also can adopt calcium fluoride or fluoridize, or combinationally use fused quartz and calcium fluoride, fused quartz and barium fluoride, calcium fluoride and barium fluoride, fused quartz and calcium fluoride and barium fluoride, especially the operation wavelength of projection optical system is not Single wavelength, but time in certain spectral range, preferably adopt the combination of two of the above-mentioned material mentioned, or use three kinds of materials simultaneously, this is beneficial to projection optical system, in optical design, for multi-wavelength system, correcting chromatic aberration must be carried out with two or more material.
The present embodiment is realized by following technical measures: lighting source is ArF laser instrument, and optical source wavelength is the numerical aperture NA=0.75 of 193.4nm, projection optical system, wave aberration RMS is 0.8nm, distorts as 0.6nm, and projection optical system reduction magnification is 4 times.
Table 1 gives the design parameter value of every a slice lens of the projection optical system of the present embodiment." sequence number " in table arranges from light end, and the beam incident surface of the first positive lens 1 is sequence number S1, and beam exit face is sequence number S2, and other minute surface sequence number by that analogy; " radius " provides the radius-of-curvature corresponding to each surface respectively; " spacing " provides the centre distance along optical axis between adjacent two surfaces, if two surfaces belong to same eyeglass, then spacing represents the thickness of this eyeglass.If two surfaces do not belong to same eyeglass, then spacing represents the distance between adjacent two eyeglasses.The design parameter of each lens is as follows:
Table 1
| Sequence number | Radius (mm) | Spacing (mm) | Material |
| Object plane | ∞ | 6.779e+001 | ? |
| S1 | ∞ | 4.882e+001 | SiO 2 |
| S2 | -2.413e+002 | 1.000e-001 | ? |
| S3 | 1.570e+002 | 1.100e+001 | SiO 2 |
| S4 | 1.020e+002 | 2.849e+001 | aspheric |
| S5 | -1.249e+002 | 1.100e+001 | SiO 2 |
| S6 | 3.340e+002 | 1.642e+001 | ? |
| S7 | -1.799e+002 | 1.100e+001 | SiO 2 |
| S8 | 1.201e+002 | 6.691e+001 | ? |
| S9 | -1.695e+002 | 5.362e+001 | SiO 2 |
| S10 | -2.537e+002 | 5.100e+001 | ? |
| S11 | 6.238e+002 | 4.632e+001 | SiO 2 |
| S12 | -4.445e+002 | 9.328e+001 | ? |
| S13 | 2.144e+002 | 5.961e+001 | SiO 2 |
| S14 | -2.318e+002 | 2.234e+001 | ? |
| S15 | 2.059e+002 | 5.134e+001 | SiO 2 |
| S16 | 5.501e+002 | 1.008e+001 | ? |
| S17 | -9.971e+002 | 1.821e+001 | SiO 2 |
| S18 | 1.117e+002 | 2.619e+001 | ? |
| S19 | -2.333e+002 | 1.100e+001 | SiO 2 |
| S20 | 1.234e+002 | 2.791e+001 | ? |
| S21 | -1.372e+002 | 1.898e+001 | SiO 2 |
| S22 | 4.026e+002 | 1.608e+001 | ? |
| S23 | -2.898e+002 | 2.942e+001 | SiO 2 |
| S24 | -2.417e+002 | 1.000e-001 | ? |
| S25 | -1.999e+002 | 4.542e+001 | SiO 2 |
| S26 | -2.969e+002 | 4.997e-001 | ? |
| S27 | 5.502e+002 | 7.285e+001 | SiO 2 |
| S28 | -3.889e+002 | 3.452e+001 | ? |
| stop | ∞ | 4.569e+001 | ? |
| S30 | 3.404e+002 | 3.513e+001 | SiO 2 |
| S31 | 2.262e+002 | 1.712e+001 | ? |
| S32 | 3.936e+002 | 5.152e+001 | SiO 2 |
| S33 | -3.953e+002 | 8.949e+001 | ? |
| S34 | 1.486e+002 | 5.545e+001 | SiO 2 |
| S35 | 2.864e+002 | 2.862e+000 | ? |
| S36 | 1.931e+002 | 5.854e+001 | SiO 2/aspheric |
| S37 | -2.170e+002 | 2.729e+001 | ? |
| S38 | -9.007e+002 | 3.834e+001 | SiO 2 |
| S39 | 1.734e+002 | 3.293e+001 | aspheric |
| S40 | 9.376e+001 | 1.100e+001 | SiO 2 |
| S41 | 5.938e+001 | 8.856e-001 | ? |
| S42 | 5.948e+001 | 5.503e+001 | SiO 2 |
| S43 | 4.687e+002 | 1.768e+001 | ? |
In upper table, " aspheric " represents that this surface is for aspheric surface.Aspheric expression formula is as follows:
In above formula, z represents aspheric rotation axes of symmetry, and y represents the height of incident ray in aspheric surface, n=1,2,3 ...C represents vertex curvature, and k is conic constant, c
nfor coefficient.Table 2 will provide aspheric correlation parameter.The conic constant k of S4, S36, S39 is 0.The asphericity coefficient of S4, S36, S39 is as follows:
Table 2
The design parameter of each lens is in practical operation above, can adjust to meet different systematic parameter requirements.
Following three kinds of evaluation meanses are adopted to test and assess to the image quality of the projection optical system of the present embodiment:
1, optical-modulation transfer function
Optical modulation function (MTF) is the direct evaluation determining resolving power of lens, and the optical-modulation transfer function (MTF) of the projection optical system of the present embodiment as shown in Figure 2 a and 2 b.Horizontal ordinate is spatial frequency, unit be line right/millimeter, ordinate is modulating function value.This figure is 193.4nm based on projection optical system operation wavelength, wavelength weight be 1 setting obtain.Fig. 2 a is the modulating function of 0,0.2,0.3,0.4,0.5 several visual field and diffraction limit, and Fig. 2 b is the modulating function of 0.7,0.8,0.9,1.0 several visual fields and diffraction limit.During by Tu Ke get, MTF ≈ 30%, systemic resolution reaches 4600 lines right/millimeter, the modulating function of each visual field and the modulating function of diffraction limit very close.Therefore, projection optical system MTF reaches diffraction limit.Illustrate that projection optical system has the resolution close to diffraction limit in whole image planes.
2, astigmatism and the curvature of field and distortion
Fig. 3 is projection optical system astigmatism, the curvature of field and distortion schematic diagram, and left side is astigmatism, curvature of field schematic diagram, and horizontal ordinate is defocusing amount, and unit is millimeter, and ordinate is object height; Right side is distortion schematic diagram, and horizontal ordinate is distortion percentage, and ordinate is object height.The distribution that in figure, left figure block curve represents the distribution of meridian focal plane shift (meridianal curvature of field), dashed curve represents sagitta of arc focal plane shift (Sagittal field curvature), the absolute value of meridianal curvature of field and Sagittal field curvature all can be controlled in 11nm; The difference of meridianal curvature of field and Sagittal field curvature is astigmatism, and therefore, astigmatism can be controlled in 11nm.Right Tu Ke get from figure, distort and change with visual field and change, in whole field range, the maximal value of distortion is-0.000000048, and this ratio is multiplied with desirable image height 12.6mm, is about 0.6nm.Therefore, distortion can be controlled in 1nm.
3, wave aberration RMS
Another key parameter evaluating picture element of optical system is wave aberration RMS.Projection optical system designed by the present embodiment, the minimum value of wave aberration RMS is 0.0020 λ (0.39nm), and maximal value is 0.0042 λ (0.81nm).So wave aberration RMS can be controlled in 1nm.
By above three kinds of image quality evaluation results, can obtain projection optical system picture element of the present invention fine, astigmatism can be controlled in 11nm, and distortion and wave aberration RMS can be controlled in 1nm.Emulated by the lithography simulation software PROLITH of specialty and find: under the configuration adopting traditional lighting (partial coherence factor is 0.5) and photoresist JSR AR165J, in certain constraint condition, (lines change resolution scope is ± 10%, process window for oval, photoresist loss be less than 10%, side wall angle is greater than 80 degree) under, the whole exposure system comprising this projection optical system can expose the lines that resolution is 100nm.Fig. 4 is the lines profile after development, and horizontal ordinate is the locus of lines, and ordinate is the thickness of photoresist.Along with the change of photoresist thickness, line size change is less; Side wall angle a is comparatively large, is all greater than 86 degree, meets photoetching process requirement.Measure along dotted line in figure, lines resolution is 100.1nm.Fig. 5 is the process window of exposure system, and horizontal ordinate represents the size of defocusing amount, and ordinate represents the size of exposure dose.Under aforesaid constraint condition, the defocusing amount size that resolution, photoresist lose, the overlapping region of side wall angle three kinds of curves is corresponding is the depth of focus of system.By Tu Ke get, the depth of focus of whole exposure system can reach 0.8 μm.Therefore, comprise the whole exposure system of this projection optical system, adopt the configuration of traditional lighting and photoresist JSR AR165J, the lines meeting photoetching 100nm node requirements can be exposed.Certainly, lighting system also can adopt ring illumination, two poles illuminations, quadrupole illuminating, and photoresist also can adopt other photoresist, as TOK TArF.
Adopt projection optical system of the present invention, under the condition of high resolving power and large-numerical aperture, effectively can reduce number of lenses, reduce the processing of system, detect, debug cost.Meanwhile, system has good image quality, can meet 100nm node requirements.Object space and the image space working distance of the optical system of the present embodiment reach 68mm, 18mm respectively.Larger degree of freedom is provided to the design of mask and silicon slice workpiece platform and processing.
Technician in the art will be appreciated that, above embodiment is only used to the present invention is described, and is not used as limitation of the invention, as long as in spirit of the present invention, change above embodiment, modification all will drop in the scope of claims of the present invention.
Claims (9)
1. a projection optical system, it is characterized in that: for by the pattern projection in object plane to picture plane, the first lens combination (G1) is mounted with along projection optical system optical axis direction, second lens combination (G2), 3rd lens combination (G3), 4th lens combination (G4) and the 5th lens combination (G5), and the first lens combination (G1), second lens combination (G2), 3rd lens combination (G3), 4th lens combination (G4) and the 5th lens combination (G5) are in same optical axis, from light beam incident direction order the first lens combination (G1), there is negative power, second lens combination (G2) has positive light coke, 3rd lens combination (G3) has negative power, 4th lens combination (G4) has positive light coke and the 5th lens combination (G5) has positive light coke, wherein:
First lens combination (G1), receives input beam, disperses, obtain and export the first divergent beams the light beam that object plane sends;
Second lens combination (G2), receives the first divergent beams, assembles the first divergent beams, obtains and exports the second divergent beams;
3rd lens combination (G3), receives the second divergent beams, disperses the second divergent beams, obtains and exports the 3rd divergent beams;
4th lens combination (G4), receives the 3rd divergent beams, assembles, obtain and export the 4th divergent beams the 3rd divergent beams;
5th lens combination (G5), receives the 4th divergent beams, assembles, obtain the first convergent beam, and the first convergent beam is converged to image planes to the 4th divergent beams; Described 5th lens combination (G5) comprises the 3rd meniscus lens (15), the 6th positive lens (16), the 7th positive lens (17), the 8th positive lens (18), the 8th negative lens (19), the 4th meniscus lens (20), the 9th positive lens (21); The plane of incidence of the 8th positive lens (18) is the second aspheric surface, utilizes the spherical aberration of the second Aspherical corrector projection optical system, coma, hereby all curvature of field; The exit facet of the 8th negative lens (19) is the 3rd aspheric surface, utilizes spherical aberration, coma, the astigmatism of the 3rd Aspherical corrector projection optical system; Through the 4th divergent beams of the 5th positive lens (14) outgoing successively through the 3rd meniscus lens (15), the 6th positive lens (16), the 7th positive lens (17), the 8th positive lens (18), the 8th negative lens (19), the 4th meniscus lens (20), for generating the first convergent beam, and export the first convergent beam by the 4th meniscus lens (20), first convergent beam outputs in image planes by the 9th positive lens (21), and described first convergent beam width is less than the width of the 4th divergent beams.
2. projection optical system according to claim 1, it is characterized in that, described first lens combination (G1) comprises the first positive lens (1), the first meniscus lens (2), the first negative lens (3) and the second negative lens (4); The exit facet of the first meniscus lens (2) is the first aspheric surface, utilizes the astigmatism of the first Aspherical corrector projection optical system, coma, distortion; The light beam that object plane sends is successively through the first positive lens (1), the first meniscus lens (2), the first negative lens (3), the second negative lens (4), for generating the first divergent beams, and exporting the first divergent beams by the second negative lens (4), described first divergent beams width is greater than the width of the light beam that object plane sends.
3. projection optical system according to claim 2, is characterized in that, described second lens combination (G2) comprises the 3rd negative lens (5), the second positive lens (6); Through the first divergent beams of the second negative lens (4) outgoing successively through the 3rd negative lens (5), the second positive lens (6), for generating the second divergent beams, and exporting the second divergent beams by the second positive lens (6), described second divergent beams width is greater than the width of the first divergent beams.
4. projection optical system according to claim 3, it is characterized in that, described 3rd lens combination (G3) comprises the 3rd positive lens (7), the 4th positive lens (8), the 4th negative lens (9), the 5th negative lens (10); Through the second divergent beams of the second positive lens (6) outgoing successively through the 3rd positive lens (7), the 4th positive lens (8), the 4th negative lens (9), the 5th negative lens (10), for generating the 3rd divergent beams, and exporting the 3rd divergent beams by the 5th negative lens (10), described 3rd divergent beams width is less than the width of the second divergent beams.
5. projection optical system according to claim 4, it is characterized in that, described 4th lens combination (G4) comprises the 6th negative lens (11), the second meniscus lens (12), the 7th negative lens (13), the 5th positive lens (14), through the 3rd divergent beams of the 5th negative lens (10) outgoing successively through the 6th negative lens (11), the second meniscus lens (12), the 7th negative lens (13), the 5th positive lens (14), for generating the 4th divergent beams, and export the 4th divergent beams by the 5th positive lens (14); Described 4th divergent beams width is greater than the width of the 3rd divergent beams.
6. projection optical system according to claim 5, is characterized in that, all lens all adopt refraction type eyeglass, does not have reflective eyeglass.
7. projection optical system according to claim 5, is characterized in that, between the 5th positive lens (14) and the 3rd meniscus lens (15), arrange aperture diaphragm.
8. projection optical system according to claim 1, is characterized in that, the numerical aperture of described system is 0.75.
9. projection optical system according to claim 1, it is characterized in that, the optical material that described first lens combination (G1), the second lens combination (G2), the 3rd lens combination (G3), the 4th lens combination (G4) and the 5th lens combination (G5) adopt refractive index to be greater than 1.5 is respectively made, described optical material is the one in fused quartz, calcium fluoride, barium fluoride, or the one combination in fused quartz and calcium fluoride, fused quartz and barium fluoride, calcium fluoride and barium fluoride, fused quartz and calcium fluoride and barium fluoride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210360715.9A CN102981249B (en) | 2012-09-21 | 2012-09-21 | Projection optical system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210360715.9A CN102981249B (en) | 2012-09-21 | 2012-09-21 | Projection optical system |
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| Publication Number | Publication Date |
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| CN102981249A CN102981249A (en) | 2013-03-20 |
| CN102981249B true CN102981249B (en) | 2015-01-28 |
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| CN201210360715.9A Expired - Fee Related CN102981249B (en) | 2012-09-21 | 2012-09-21 | Projection optical system |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103472586B (en) * | 2013-09-18 | 2015-06-24 | 中国科学院光电技术研究所 | Projection optical system |
| CN111381346B (en) * | 2018-12-30 | 2021-05-11 | 上海微电子装备（集团）股份有限公司 | Photoetching projection objective lens |
| CN112817122B (en) * | 2019-11-18 | 2022-05-20 | 成都理想境界科技有限公司 | Projection objective and scanning display device |
| CN112394481B (en) * | 2020-11-18 | 2023-10-24 | 西安玄瑞光电科技有限公司 | Ultra-large relative aperture low-light lens |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6349005B1 (en) * | 1998-11-30 | 2002-02-19 | Carl-Zeiss-Stiftung | Microlithographic reduction objective, projection exposure equipment and process |
| CN102662307A (en) * | 2012-05-02 | 2012-09-12 | 中国科学院光电技术研究所 | High-resolution projection optical system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| DE10151309A1 (en) * | 2001-10-17 | 2003-05-08 | Carl Zeiss Semiconductor Mfg S | Projection exposure system for microlithography for lambda <200 nm |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6349005B1 (en) * | 1998-11-30 | 2002-02-19 | Carl-Zeiss-Stiftung | Microlithographic reduction objective, projection exposure equipment and process |
| CN102662307A (en) * | 2012-05-02 | 2012-09-12 | 中国科学院光电技术研究所 | High-resolution projection optical system |
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