Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B9/00—Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
  • G03F7/70975—Assembly, maintenance, transport or storage of apparatus
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B13/00—Optical objectives specially designed for the purposes specified below
  • G02B13/24—Optical objectives specially designed for the purposes specified below for reproducing or copying at short object distances
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/20—Exposure; Apparatus therefor
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70216—Mask projection systems
  • G03F7/70241—Optical aspects of refractive lens systems, i.e. comprising only refractive elements
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
  • G03F7/7095—Materials, e.g. materials for housing, stage or other support having particular properties, e.g. weight, strength, conductivity, thermal expansion coefficient
  • G03F7/70958—Optical materials or coatings, e.g. with particular transmittance, reflectance or anti-reflection properties

Definitions

• the invention relates to a refractive projection lens for Mi rolithography that consists of a first belly, a waist and a second belly in the direction of propagation of the light.
• Such refractive projection lens are also referred to as a waist system.
• Such waist systems are known for example from US60 / 160799, EP 1 061 396 A2 and from EP 1 139 138 AI or WO 01/23933 -WO 01 / 23935_. It is already known from these documents that the first or the first two lenses on the object side have negative refractive power. It is also known from these writings that the use of aspheres can improve the image quality. Since the resolution that can be achieved with a projection lens increases proportionally with the numerical aperture of the projection lens on the image side and continues to increase in proportion to the reciprocal of the observation wavelength, there is a tendency to provide projection lenses with the largest possible numerical aperture to increase the resolution.
• the invention has for its object to provide a refractive projection lens that has reduced manufacturing costs due to a reduced material use with a high numerical apatur.
• menisci have a convex surface on the side facing the object.
• Figure 1 projection exposure system
• Figure 2 projection lens for the wavelength 193 n
• FIG. 3 projection objective for the exposure wavelength 193 nm
• FIG. 4 projection objective for the wavelength 193 nm
• Figure 5 Projection lens for the exposure wavelength 157 nm.
• FIG. 6 projection objective for the wavelength 193 nm
• FIG. 7 projection objective for the exposure wavelength 193 nm
• FIG. 8 projection objective for the wavelength 193 nm
• Figure 9 Projection objective for the exposure wavelength 193 nm.
• the projection equipment 101 has an illumination device 103 and a projection objective 105.
• the projection objective 105 comprises a lens arrangement 121 with an aperture diaphragm 119, an optical axis 107 being defined by the lens arrangement 121.
• a mask 109 is arranged between the illumination device 3 and the projection objective 105 and is held in the beam path by means of a mask holder 111.
• Such masks 109 used in microlithography have a micrometer to nanometer structure, which is imaged on the image plane 113 by the projection objective 105 or by the lens arrangement 121 down to a factor of 10, in particular by a factor of 4.
• 1h of the image plane 113 is a substrate or ' positioned by a substrate holder 117. a wafer 115 held.
• the minimum structures that can still be resolved depend on the wavelength of the light used for the exposure and on the aperture of the projection lens 5; being the maximum achievable resolution the projection exposure system 1 increases with decreasing length of the lens and with increasing numerical aperture of the projection lens 5 on the image side.
• FIGS. 2 to 5 show possible lens arrangements 121 of the projection objectives 105 in more detail.
• These lens arrangements 1 21 shown which are also referred to as designs, have a numerical aperture of 0.85 or 0.9 on the image side.
• the designs shown in FIGS. 2 to 4 and 6 to 9 are designed for the exposure wavelength of 193 nm.
• the projection objective shown in FIG. 5 is designed for the exposure wavelength of 157 nm. All of these designs have in common that the aberrations that occur are very small and can therefore be resolved with structure widths of up to 70 nm.
• the wavefront errors are less than 5/1000 of the wavelength of the light used for the exposure and, on the other hand, the distortion is less than 1 nm.
• the longitudinal color error is less than 380 nm pm.
• the large field size of 26 x 10.5 mm 2 in which the image is corrected in such a high quality, enables productive use in microlithography. Due to the design of the field size or field format, these projection objectives with such lens arrangements are particularly suitable for use in hthographic scanning devices.
• the lens arrangements 121 have a first belly 123, a waist 125 and a second belly 127.
• the waist 125 comprises a point of the narrowest constriction 129 in the second belly a system panel 119 is arranged.
• the first lens group LG1 comprises three negative lenses with the lens surfaces 2-7.
• the first two negative lenses are preferably bent towards the object.
• the third negative lens is preferably a meniscus lens that is bent towards the image. It connects to this first lens group the second lens group LG2, which has positive refractive power, with a lens of maximum diameter of the first belly in this second lens group is arranged.
• This second lens group LG2 preferably exclusively comprises lenses of positive refractive power.
• the third lens group LG3, the negative refractive power on ice, is connected to this lens group LG2.
• This third lens group LG3 comprises at least three successive lenses of negative refractive power.
• This third lens group LG3 is followed by a fourth lens group LG4, which has positive refractive power.
• This fourth lens group LG4 ends before the aperture.
• a fifth lens group LG5 is formed by the lenses arranged after the system diaphragm 119, which also has positive refraction.
• This fifth lens group LG5 comprises a lens of maximum diameter in the second belly, this diameter being designated D2.
• All of these examples are characterized by an excellent correction of the wavefront.
• the image errors that occur are corrected to values less than 5/1000 of the length.
• the main beam distortion is corrected to values less than 1 nm.
• the advantageous effect of the existing BrecMcraft distribution has been reinforced by the use of aspheres.
• the two aspheres on the diverging lenses in the first lens group LG1 are mainly used to correct the distortion and the object and image-side telecentricity of the main rays of the outermost field point.
• the third lens group LG3 begins with a weakly diverging meniscus, the convex side of which is arranged facing the mask 109.
• a lens with positive refractive power and at least two strongly diverging biconcave lenses is attached to this meniscus. If aspheres are provided in this second lens group LG2, they are arranged on a concave surface facing the wafer.
• At least one diverging meniscus is arranged between the waist and the diaphragm, that is to say in the fourth lens group LG4.
• the latter has a concave surface facing the wafer and thus has a shape similar to that of the diverging meniscus immediately behind the diaphragm.
• the correlation state is represented for each example on the basis of curves for spherical aberration and astigmatism and the key figures for the RMS value of the wavefront in FIGS. 2a-2c ... to FIGS. 5a-5c.
• the longitudinal color error CHL which is determined as follows:
• the use of only one material is provided in the exemplary embodiments shown in FIGS. 2-9, it being possible to achieve excellent image quality with regard to the chromatic aberrations precisely through the arrangement of the menisci provided after the point of the narrowest constriction.
• This image quality is characterized by a longitudinal chromatic aberration or "axial color” less than 385nm per pm in.
• the Farbver 'size approximation error or "lateral color” is less than 0.8 pprn pm, which is an excellent value. This corresponds to a color magnification error of 1 lnm / pm at the edge of the picture. Where pp stands for parts per million.
• a second material which may also be used, can be provided for color error correction and / or high energy density occurring in standing areas to avoid compaction and rarefaction effects.
• Compaction and rarefaction effects mean the material-dependent changes in refractive index in areas of high energy density.
• the excellent image quality with regard to color errors is significantly supported by the shapes of the two bellies.
• the ratio of the maximum diameters of the first belly Di and the second belly D 2 satisfies the following conditions 0.8 ⁇ D1 / D2 ⁇ 1.1. The following preferably applies: 0.8 ⁇ D1 / D2 ⁇ 1.0.
• all lens arrangements 121 have a numerical aperture of at least 0.85.
• this special arrangement in a lens arrangement which has a lower numerical index on the image side, in order either to provide a larger field with undiminished image quality or to further improve the image quality by way of the quality shown in the exemplary embodiments or to improve its use of aspheres.
• the designs are characterized by low beam deflections or beam angles on most surfaces despite the high numerical apatur. As a result, only a few higher-order image errors are generated.
• the strongly yellowed menisci which have negative refractive power and are arranged in the fourth and fifth lens groups, are provided.
• Most lenses, however, at least 80% of all lenses have lens surfaces on which the incoming light has an angle of incidence of less than 60 °. The same applies to the lens surfaces at which the radiation emerges again.
• a free area which is designated as L AP
• panels can be used which can be adjusted depending on the requirements of the image.
• a wide variety of diaphragms can also be used, and diaphragm holders can be provided which already have a mechanism for adjusting the diaphragm, since sufficient space must be available to provide such a construction.
• the last two lenses arranged in front of the system aperture 119 have contributed significantly to the fact that the free space L AP could be provided.
• the small diameters D1 and D2 in the two bellies 123, 127, and the short overall length of 1000-1150 mm and the small number of lenses made it possible to reduce the lens material required. It was possible to achieve that the lens mass m is less than 55 kg in some exemplary embodiments, see Table 1.
• Lenses of the lens arrangements shown in FIGS. 2-9 are in the range from 54 to 68 kg.
• L is the length measured from the reticle to the wafer
• NA is the numerical aperture on the image side
• D AX is the maximum diameter of the system, i.e. 1 or D2
• 2yb is the diameter of the image field , It is particularly advantageous if the maximum diameter of the first belly D1 is at most equal to the maximum diameter of the second belly D2.
• L geo is the sum of the center thicknesses of all lenses in the lens.
• LV is a measure of the free space around a system aperture, with L AP being the free distance from the last lens surface before the aperture to the first lens surface after the aperture.
• L geo is the sum of the center thicknesses of all lenses arranged in the lens and L is the distance from image plane O 'to object plane O.
• P is the arrow height as a function of the radius h (height to the optical axis 7) with the aspherical constants K, Ci to Cn given in the tables.
• R is the vertex radius given in the tables.
• FIGS. 2a to 2c The distribution of the image errors over the image is shown in FIGS. 2a to 2c.
• the spherical longitudinal aberration is shown in FIG. 2a, the relative opening being plotted on the vertical axis and the longitudinal aberration being plotted on the horizontal axis.
• the course of the astigmatism can be seen from FIG. 2b.
• the object height is plotted on the vertical axis and the defocusing is plotted in mm on the horizontal axis.
• the distortion is shown in FIG. 2c, the distortion being plotted on the horizontal axis in% compared to the object height on the vertical axis.
• FIGS. 3a-3c show the spherical aberration, the astigmatism and the distortion as already described with reference to FIGS. 2a-2c.
• FIGS. 4a-4c The imaging quality with regard to spherical aberration, astigmatism and distortion are shown in FIGS. 4a-4c.
• OOOOOOOOO 31 OOOOOOOOO L710 0.99998200 • 56., 080

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Epidemiology (AREA)
• Public Health (AREA)
• Optics & Photonics (AREA)
• Lenses (AREA)
• Prostheses (AREA)
• Endoscopes (AREA)

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• 2003
  • 2003-02-06 JP JP2003573496A patent/JP2005519332A/ja active Pending
  • 2003-02-06 KR KR10-2004-7013547A patent/KR20040089688A/ko not_active Ceased
  • 2003-02-06 WO PCT/EP2003/001147 patent/WO2003075096A2/de not_active Ceased
  • 2003-02-06 EP EP03743308A patent/EP1483626A2/de not_active Withdrawn
  • 2003-02-06 AU AU2003210214A patent/AU2003210214A1/en not_active Abandoned
  • 2003-03-03 WO PCT/US2003/006592 patent/WO2003075049A2/en not_active Ceased
  • 2003-03-03 AU AU2003230593A patent/AU2003230593A1/en not_active Abandoned

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