WO2005031821A1 - 光学系、露光装置、およびそれらの製造方法 - Google Patents
光学系、露光装置、およびそれらの製造方法 Download PDFInfo
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- WO2005031821A1 WO2005031821A1 PCT/JP2004/014149 JP2004014149W WO2005031821A1 WO 2005031821 A1 WO2005031821 A1 WO 2005031821A1 JP 2004014149 W JP2004014149 W JP 2004014149W WO 2005031821 A1 WO2005031821 A1 WO 2005031821A1
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- optical
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- optical system
- fluoride
- birefringence
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Classifications
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- 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
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/7055—Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
- G03F7/70566—Polarisation control
-
- 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
- G03F7/70966—Birefringence
Definitions
- the present invention relates to an optical system, an exposure apparatus, and a method for manufacturing the same, and particularly to an exposure apparatus useful for manufacturing microdevices such as semiconductor devices, imaging devices, liquid crystal display devices, and thin-film magnetic heads by lithography. It concerns the device.
- a secondary light source is formed as a substantial surface light source composed of a large number of light sources.
- the light flux from the secondary light source is condensed by the condenser lens, and then illuminates the mask on which the predetermined pattern is formed in a superimposed manner.
- a KrF excimer laser light source that supplies light having a wavelength of about 248 nm and an ArF excimer laser light source that supplies light having a wavelength of about 193 nm are used as exposure light sources.
- the wavelength of exposure light becomes shorter, the types of optical materials that can withstand practical use due to light absorption are limited.
- the absorption edge wavelength is short!
- a mirror-type beam splitter is arranged in the optical path, and The reflected light from the beam splitter is detected as monitor light.
- the beam splitter has a polarization characteristic that the reflectance changes depending on the polarization state of the incident light. Therefore, in order to control the exposure light amount on the wafer to be substantially constant during the exposure, and perform good exposure, it is necessary to stabilize the polarization state of the light incident on the beam splitter.
- a light transmitting member such as fluorite has a property of receiving a laser beam and changing the polarization state of emitted light. discovered.
- the present invention has been made in view of the above-described problems, and can stabilize the polarization state of light incident on a beam splitter disposed in an optical path. It is an object of the present invention to provide an exposure apparatus capable of controlling exposure light amount to be substantially constant during exposure based on reflected light and performing good exposure, a method of manufacturing the same, and an exposure method using the same.
- the present invention also relates to an exposure apparatus that uses, for example, an ArF excimer laser light source or a KrF excimer laser light source to stabilize the polarization state of light incident on a beam splitter disposed in the optical path. It is an object of the present invention to provide an optical system capable of realizing the above, and a manufacturing method thereof.
- a light transmitting member such as fluorite has the property of changing the polarization state of emission light upon irradiation with laser light. And found that the above-mentioned object was achieved by using an optical member made of an optical material having a variation in birefringence before and after laser beam irradiation within a predetermined range under predetermined use conditions, The present invention has been completed.
- the present invention provides the following optical system and method for manufacturing the same, an exposure apparatus and a method for manufacturing the same, and an exposure method using the exposure apparatus, which solves the above-mentioned problems.
- An optical system that uses light having a wavelength of 250 nm or less as transmitted light, and is an optical material having transparency to the light, wherein 0.1 lmj / cm 2 / pulse-150 mjZcm 2 Under certain conditions of use in the energy density range of the Z pulse and the pulse frequency range of 0.1 kHz to 100 MHz, the birefringence in the initial state before the light enters and the equilibrium state after the light enters Light whose difference from refraction is 3nmZcm or less An optical system in which optical members made of scientific materials are arranged.
- ⁇ 2> The optical device according to ⁇ 1>, wherein the sum of the optical path lengths in the optical member made of the optical material is 70% or more of the sum of the optical path lengths in all the optical members constituting the optical system. system.
- optical material is at least one selected from the group consisting of a fluoride crystal, quartz glass, and quartz.
- the fluoride crystal is at least one selected from the group consisting of calcium fluoride, barium fluoride, lithium fluoride, sodium fluoride, and strontium fluoride. Optical system.
- An exposure apparatus including an illumination optical system for illuminating a mask using light having a wavelength of 250 nm or less and a projection optical system for projecting and exposing the pattern image of the mask on a substrate to be exposed.
- An exposure apparatus provided with an optical member made of an optical material having a difference between a birefringence in an initial state before the light is incident and a birefringence in an equilibrium state after the light is incident is 3 nmZcm or less.
- the sum of the optical path lengths in the optical member made of the optical material is the total of the optical members constituting the optical system.
- the exposure apparatus according to ⁇ 5> which is 70% or more of the total optical path length in the medium.
- optical material is at least one selected from the group consisting of a fluoride crystal, quartz glass, and quartz.
- the fluoride crystal is at least one selected from the group consisting of calcium fluoride, barium fluoride, lithium fluoride, sodium fluoride, and strontium fluoride.
- Exposure equipment Exposure equipment.
- An optical material having a difference between a birefringence in an initial state before the light is incident and a birefringence in an equilibrium state after the light is incident is 3 nmZcm or less under predetermined use conditions in several ranges.
- An optical system manufacturing method including:
- optical material is at least one selected from the group consisting of a fluoride crystal, quartz glass, and quartz.
- the fluoride crystal is at least one selected from the group consisting of calcium fluoride, barium fluoride, lithium fluoride, sodium fluoride, and strontium fluoride. Method for manufacturing an optical system.
- An exposure apparatus comprising: an illumination optical system that illuminates a mask using light having a wavelength of 250 nm or less; and a projection optical system that projects and exposes a pattern image of the mask onto a substrate to be exposed.
- An optical material having a light-transmitting property comprising: an energy density range of 0.1 lmj / cm 2 / pulse-150 mjZcm 2 Z pulse; and a predetermined use condition in a pulse frequency range of 0.1 kHz to 100 MHz.
- an optical member made of an optical material having a difference of 3 nmZcm or less between an initial state birefringence before the light is incident and an equilibrium state birefringence after the light is incident is selected and prepared.
- the members necessary for the exposure apparatus are assembled together with the optical member made of the optical material, and the illumination optical system and the Z or the projection optical system are made of the optical part made of the optical material. Obtaining an exposure apparatus in which materials are arranged;
- the sum of the optical path lengths in the optical member made of the optical material is equal to the optical path in all the optical members constituting the optical system.
- ⁇ 15> The method for manufacturing an exposure apparatus according to ⁇ 13>, wherein the optical material is at least one selected from the group consisting of a fluoride crystal, quartz glass, and quartz.
- the fluoride crystal is at least one selected from the group consisting of calcium fluoride, barium fluoride, lithium fluoride, sodium fluoride, and strontium fluoride. Of manufacturing an exposure apparatus.
- the mask is illuminated with light having a wavelength of 250 nm or less, and the pattern image of the mask is exposed.
- an optical member formed of, for example, a fluoride crystal (fluorite), quartz glass or quartz, birefringence when illumination light is incident under predetermined use conditions
- An optical member having an optical material strength of 3 nmZcm or less is used as an optical member.
- the fluctuation of the polarization state caused by the birefringence fluctuation of the optical member can be suppressed to a small degree, so that the polarization state of the light incident on the beam splitter disposed in the optical path can be stabilized, and as a result, Good exposure can be performed by controlling the amount of exposure light to be substantially constant during exposure based on the light reflected from the beam splitter.
- FIG. 1 schematically shows how a polarization state changes after passing through a medium when a laser beam is irradiated in the form of linearly polarized light into an optical medium in which irradiation fluctuation occurs.
- FIG. 2 is a diagram schematically showing a preferred example of an experimental system for evaluating birefringence of an optical material according to the present invention.
- FIG. 3 is a diagram schematically showing a state in which incident linearly polarized light is preserved as it is when no birefringence exists in the sample.
- FIG. 4 shows that the incident linearly polarized light is elliptical when the sample has birefringence in the initial state. It is a figure which shows the state changed to circularly polarized light typically.
- FIG. 5 is a diagram schematically showing a state in which the birefringence of the sample fluctuates and elliptically polarized light changes.
- FIG. 6 is a graph showing the relationship between measurement conditions (repetition frequency X fluence) and birefringence (retardation).
- FIG. 7 is a diagram schematically showing a configuration of a preferred embodiment of an exposure apparatus of the present invention including the optical system of the present invention.
- FIG. 8 is a graph showing, as a result of continuous irradiation with an ArF excimer laser at a frequency of lkHz and a fluence of lOmjZcm 2 , fluctuations in sensor output immediately after the start of irradiation in%.
- FIG. 9 is a flowchart of a method for obtaining a semiconductor device as a micro device.
- FIG. 10 is a flowchart of a method for obtaining a liquid crystal display element as a micro device.
- the optical member used in the present invention is an optical material having a transmittance for light having a wavelength of 250 nm or less, and has an energy density range of 0.1 lnijZcm 2 Z pulse to 150 mjZcm 2 Z pulse. And under a specified use condition in the pulse frequency range of 0.1 kHz to 100 MHz, the difference between the birefringence in the initial state before the light is incident and the birefringence in the equilibrium state after the light is incident is 3 nmZcm or less.
- the optical material is an optical member.
- the specific form of the powerful optical member is not particularly limited, and is preferably used as various light-transmitting refraction members (such as lenses) used in an optical system such as an exposure apparatus.
- the main mechanism of fluctuation of birefringence due to irradiation of light (laser light) to an optical material (optical medium) is absorption of irradiation light by a medium, heat generation due to absorption, thermal expansion due to heat generation, and thermal expansion.
- the present inventors presume that the fluctuation of the internal stress state is accompanied by the fluctuation of the stress birefringence caused by the fluctuation of the internal stress state. That is, the amount of change in stress birefringence is the amount of change in irradiation birefringence, which is the amount to be evaluated here.
- a change in the polarization state of one laser beam after passing through the medium due to the change in the stress birefringence is a fatal problem in the conventional polarization optical system.
- Birefringence is roughly classified into birefringence, stress birefringence, intrinsic birefringence, birefringence due to application of an electric field, and the like due to the symmetry of the structure itself.
- birefringence caused by the symmetry of the structure itself is used when the birefringence phenomenon is intentionally used in an optical member (optical element).
- optical member optical element
- Exists intrinsic birefringence is due to the repetitive structure of the crystal, and is generally an amount of birefringence that does not matter at all unless it approaches the absorption edge wavelength.
- birefringence While the above two types of birefringence are the essential birefringence that exists even when the optical medium is in an ideal state, stress birefringence is when the residual stress exists inside the optical medium or when external stress is present. This is the birefringence induced when stress is generated for a specific reason. This is due to the birefringence caused by the deviation from the ideal state of the optical medium, which is a perfect isotropic body in the case of glass, or a perfectly ideal atomic structure in the case of a crystal. In addition, the appearance of birefringence differs depending on how the symmetry is reduced due to the deviation.
- the mechanism described above causes a change in the stress state in the optical medium.
- the irradiation power density is an amount determined by the product of the fluence of the irradiation laser and the repetition frequency.
- Such a change in birefringence occurs in about 10 seconds to several tens of seconds after the start of irradiation, and then saturates and stabilizes. This is thought to be the transition of the internal stress state to a new equilibrium state due to the balance between absorption heat generation and cooling of the optical medium.
- this new equilibrium state is determined by the fluence of the irradiation laser and the repetition frequency, and has a proportional relationship as long as it is determined by the amount of change in the birefringence (retardation).
- the birefringence saturated and stabilized after the start of light irradiation in this way is referred to as “birefringence in an equilibrium state (after light is incident)” in the present invention.
- the present inventors have also confirmed that such a new equilibrium state birefringence rapidly returns to the initial state of birefringence when laser irradiation is stopped, and almost recovers in several tens of seconds. are doing.
- the birefringence is evaluated in the retardation amount and the fast axis direction. It has been confirmed that the birefringence variation due to irradiation is generally preserved in the direction of the fast axis of the birefringence in the initial state, and if the variation in retardation due to irradiation can be evaluated, You can know the state of birefringence. Also, as described above, the amount of fluctuation of the retardation is proportional to both the fluence of the irradiation laser and the repetition frequency (that is, it is proportional to the irradiation power density). It is also possible to predict the behavior under other conditions.
- FIG. 1 shows how the initial state birefringence shifts to a new equilibrium state birefringence due to irradiation fluctuation.
- FIG. 1 schematically shows how the state of polarization changes after passing through a medium when laser light is irradiated in the form of linearly polarized light into an optical medium in which irradiation fluctuations occur.
- linearly polarized light is irradiated at an angle ⁇ with respect to the fast axis of birefringence in the initial state of the optical medium. This linearly polarized light and the intrinsic polarization component in the fast axis direction in the optical medium are retarded.
- the light is decomposed into intrinsic polarized light segments in the running axis direction and travels through the medium.
- a phase difference proportional to the optical path length occurs between the two due to the difference in the refractive index between the two polarization components, and the light coming out of the optical medium is elliptically polarized as shown in Fig. 1.
- the present inventors speculate.
- the elliptically polarized light changes to the initial state shown in FIG. This is elliptically polarized light due to birefringence. In other words, it is the polarization state immediately after irradiation and before thermal stress due to absorption occurs.
- the birefringence of the medium changes toward a saturation state at the same time as the start of irradiation.
- birefringence is evaluated as the difference between the retardation in the initial state and the retardation in a new equilibrium state after irradiation.
- the birefringence in the initial state is a combination of stress birefringence and intrinsic birefringence in a state where there is no absorption heat generated by irradiation.
- the intrinsic birefringence is not affected by the irradiation laser light, but the stress birefringence is affected by the irradiation laser light according to the irradiation power density.
- the determination of the retardation corresponding to the birefringence in the initial state is made by determining the Y intercept of the straight line connecting the plot of the measured retardation value (vertical axis) against the irradiation power density (horizontal axis) (retardation expected when the power density is 0). Power is also required.
- the birefringence in such an initial state can be obtained by measuring several points at least within a range of 100 Hz to 1.4 kHz.
- FIG. 2 shows a preferred example of a measuring apparatus (experimental system) for evaluating birefringence of an optical material (optical medium) according to the present invention.
- the evaluation system shown in Fig. 2 consists of an ArF excimer laser light source 21, a polarizer 22, a rotating sample holder 23, an analyzer 24, a first sensor 25, and a second sensor 26. (Not shown) ing.
- the ArF excimer laser light source 21 is G20A2-1F manufactured by Gigaphoton, the wavelength of one irradiation laser beam (ArF light L) is 193 nm, and the repetition frequency is 100 Hz to 1.4 kHz.
- a plate volatilizer is used for the analyzer 24 and the polarizer 22, and the polarizer 22 is arranged so as to be parallel to the polarization direction (horizontal polarization in the figure) of the ArF light beam L, and the linear polarization of the laser light is used. Is increasing the character.
- the extinction ratio at this time is less than 1Z5000.
- the analyzer 24 is arranged so as to be orthogonal to the polarizer 22, that is, in a cross-cor relationship.
- the analyzer 24, which is a plate volatilizer has the same function as a polarizing beam splitter, and sends the ArF light L having a polarization component (horizontal polarization in the figure) parallel to the polarizer 22 to the first sensor 25.
- the optical material (evaluation sample) 27 to be evaluated has been polished on two sides, and is set on a rotating sample holder 23 between the polarizer 22 and the analyzer 24. Then, by rotating the rotating sample holder 23 (indicated by an arrow 28 in the figure), the setting is made so that the fast axis of the sample 27 and the angle formed by the polarizer 22 and the analyzer 24 are both 45 °. Do.
- FIGS. 3 to 5 show the principle of measuring the amount of change in the birefringence of the optical material according to the present invention using the above-described measuring apparatus. That is, first, the irradiation laser light (ArF light L) is irradiated by the polarizer 22 in the form of linearly polarized light so as to have a vibration plane in a direction at 45 ° to the fast axis of the sample 27. At this time, if there is no birefringence in the sample 27, the linearly polarized light is stored as linearly polarized light, and all light is guided to the first sensor 25 (FIG. 3). That is, the incident linearly polarized light is preserved as it is, 100% is detected by the first sensor 25, and no output appears on the second sensor 26.
- the irradiation laser light ArF light L
- the polarizer 22 in the form of linearly polarized light so as to have a vibration plane in a direction at 45 ° to the fast axis of the sample 27.
- Equation (1) P is the output of the first sensor 25, P is the output of the second sensor 26, and ⁇ is the phase difference
- R is birefringence (retardation)
- ⁇ is the wavelength of the laser (here, 193 nm).
- the size of the retardation changes due to birefringence fluctuation, and at the same time the shape of the elliptically polarized light changes (Fig. 5). Accordingly, the output ratio between the first sensor 25 and the second sensor 26 also changes. Therefore, the birefringence (retardation) in the equilibrium state after fluctuation is calculated from the output ratio at this time, and the difference between this and the birefringence (retardation) in the initial state is a quantity representing the magnitude of birefringence fluctuation due to irradiation. Desired.
- the amount of fluctuation of the retardation due to the birefringence fluctuation thus obtained is large, this means that the change in the polarization state due to the birefringence fluctuation is large, and is given to the polarization optical system.
- the present inventors have found that the effect is large.
- the degree of change in the polarization state which is not only the amount of fluctuation of the retardation, but also the geometrical relationship between the fast axis direction of the optical medium and the vibration direction of the incident light beam.
- the intrinsic physical quantity of the optical medium itself in the phenomenon of birefringence fluctuation is the fluctuation amount of the retardation, and this is used in the present invention as an index for selecting an optical material (optical medium).
- sample 14 was irradiated with a 193 nm excimer laser beam in the range of (repetition frequency X fluence) of 20 mW / cm 2 or less. Then, measurement is performed based on the principle shown in Figs.
- the birefringence amount (retardation) of Samples 1-4 was calculated by the above equations (1) and (2).
- Fig. 6 shows the obtained results.
- FIG. 6 plots the birefringence (retardation) for each sample under each measurement condition (repetition frequency X fluence).
- the amount of change in birefringence (the amount of change in retardation) is proportional to the product of the repetition frequency and the fluence
- the plot of each sample can be connected by a straight line, and the Y intercept represents the initial state. Birefringence was required. Therefore, the amount of change in birefringence (the amount of change in retardation) under specific use conditions is calculated as the difference between the retardation and the retardation of the Y-intercept under the use conditions (indicated by the arrow in FIG. 6). was done.
- the variation of the birefringence (the variation of the retardation) of Sample 1 and Sample 4 shown in Fig. 6 were determined to be 6.2 nmZcm and 0.8 nmZcm, respectively. Therefore, the amount of variation in birefringence of sample 4 is 3 nmZcm or less, and the force that can be used as an optical material that also contributes to the present invention The force of sample 1 exceeds 3 nm / cm The force according to the present invention It was confirmed that it could not be used as an optical material.
- the difference between the birefringence in the initial state and the birefringence in the equilibrium state (variation in birefringence) in the wavelength range of 250 nm or less is obtained.
- a predetermined use condition in the energy density range of 0.1 mjZcm 2 Z pulse and 150 mjZcm Z pulse and the pulse frequency range of 0.1 kHz to 100 MHz it is 3 nmZcm or less (more preferably InmZcm or less).
- the variation in the polarization state caused by the birefringence variation of the optical member increases, and the optical member is disposed in the optical path in an exposure apparatus described later.
- the polarization state of the incident light on the beam splitter becomes unstable, and it becomes difficult to control the amount of exposure light based on the reflected light from the beam splitter.
- the predetermined use conditions in the present invention include a wavelength range of 250 nm or less (more preferably, 150 to 250 nm), an energy density range of 0.1 lmjZcm 2 Z pulse and 150 mjZcm 2 Z pulse, and (more preferably, 0.1 kHz to 10 MHz).
- 0.lmjZcm 2 Z noise is a value assuming a light transmitting member in the projection optical system.
- 150mjZcm 2 Z pulse is the limit value of the material of fluorite.
- the pulse frequency of 0.1 kHz is a limit value in consideration of the throughput of the exposure apparatus, and the pulse frequency of 100 MHz is a value assuming a solid-state laser light source.
- the actual upper limit of the frequency varies depending on the type of laser light source, but the upper limit of the pulse frequency when a solid-state laser light source is assumed is about 100 MHz, and the pulse frequency when an excimer laser light source is assumed.
- the upper limit of the pulse frequency is about 10 kHz, and the upper limit of the pulse frequency assuming the current excimer laser light source is about 8 kHz.
- FIG. 7 is a diagram schematically showing a configuration of a preferred embodiment of the exposure apparatus of the present invention including the optical system of the present invention.
- the exposure apparatus of the present embodiment includes a light source 1 for supplying exposure light (illumination light).
- a light source 1 for supplying exposure light (illumination light).
- the light source 1 for example, an ArF excimer laser light source that supplies light having a wavelength of about 193 nm or a KrF excimer laser light source that supplies light having a wavelength of about 248 nm can be used.
- the substantially parallel light beam emitted from the light source 1 is shaped into a light beam having a predetermined rectangular cross section through a beam transmitting system 2 having a known configuration. Incident.
- the beam transmission system 2 converts the incident light beam into a light beam having a cross section of an appropriate size and shape, guides the light beam to the beam shape variable unit 3, and changes the position and angle of the light beam entering the subsequent beam shape variable unit 3. It has a function to actively compensate for fluctuations.
- the light beam having passed through the beam shape variable unit 3 enters a microlens array (or fly-eye lens) 4.
- the beam shape variable unit 3 includes, for example, a diffractive optical element and a variable power optical system, and controls the size and shape of the illumination field formed on the entrance surface of the microlens array 4, and thus the rear side of the microlens array 4. It has the function of changing the size and shape of the surface light source formed on the focal plane (illumination pupil plane).
- the microlens array 4 is an optical element composed of, for example, a large number of microlenses having a positive bending force arranged vertically and horizontally and densely.
- the microlens group is formed by etching a parallel plane plate. It is constituted by forming. Where the micro lens array Is smaller than each lens element forming the fly-eye lens.
- the microlens array has a large number of microlenses (microrefractive surfaces) formed integrally without being isolated from each other. However, it is microscopic in that the lens elements are arranged vertically and horizontally.
- an optical integrator such as a diffractive optical element or a prismatic rod-type integrator can be used.
- the light beam incident on the microlens array 4 is two-dimensionally divided by a large number of minute lenses, and a light source is formed on the rear focal plane of each minute lens on which the light beam has entered.
- a substantial surface light source hereinafter, referred to as "secondary light source” having a large light source power is formed.
- the light flux of the secondary light source formed on the rear focal plane of the microlens array 4 passes through the beam splitter 5a and the condenser optical system 6, and then illuminates the mask blind 7 in a superimposed manner.
- a rectangular illumination field corresponding to the shape and the focal length of each micro lens constituting the micro lens array 4 is formed on the mask blind 7 as the illumination field stop.
- the light beam passing through the rectangular opening (light transmitting portion) of the mask blind 7 is condensed by the imaging optical system 8 and then superimposed on a mask (reticle) M on which a predetermined pattern is formed. Light up.
- the imaging optical system 8 forms an image of the rectangular opening of the mask blind 7 on the mask M.
- the light flux transmitted through the pattern of the mask M forms an image of the mask pattern on the wafer W as a photosensitive substrate via the projection optical system PL.
- the pattern of the mask M are sequentially exposed.
- the exposure apparatus of the present embodiment is a light amount monitor for detecting the light amount (light intensity) of the illumination light (exposure light) based on the light taken out of the illumination light path via the beam splitter 5a.
- the light amount monitor 5 detects the reflected light from the beam splitter 5a and detects the reflected light from the beam splitter 5a. And supplies the output of the photodetector 5b to the control unit 10.
- the light amount monitor 5 is not limited to the optical path between the microlens array 4 and the condenser optical system 6, but can also detect the light amount based on light extracted from another appropriate optical path force.
- the control unit 10 controls the output of the light source 1 based on the detection result of the light amount monitor 5. That is, the control unit 10 controls the light emission output of the light source 1 in accordance with the fluctuation of the light intensity detected by the light amount monitor 5 so that the exposure light amount for the wafer W becomes substantially constant during the exposure. Further, the control unit 10 controls the operation of the beam shape changing unit 3 according to the pattern characteristics (fineness, directionality, etc.) of the mask M.
- fluorite has the property of changing the polarization state of emitted light upon irradiation with laser light.
- the change in the polarization state due to fluorite is remarkable.
- the polarization state of the light that has passed through the fluorite during the laser beam irradiation start force for several tens of seconds gradually fluctuates, and then the polarization state of the emitted light is settled to a substantially steady state.
- the change in the polarization state due to the fluorite almost recovers in several tens of seconds when the irradiation of the laser beam is stopped. Therefore, when laser irradiation to fluorite and irradiation stop are repeated, every time laser irradiation is started, the polarization state of light passing through the fluorite changes, which in turn causes a change in the beam splitter 5a.
- the polarization state of the incident light will fluctuate.
- the light amount monitor 5 when the polarization state of the light incident on the beam splitter 5a changes, the reflectance changes (the ratio of the polarization component of the reflected light changes) due to the polarization characteristics of the beam splitter 5a, and the light detection The intensity of the reflected light reaching the vessel 5b also changes. As a result, even if the output of the light source 1 does not change, the detection result of the light amount monitor 5 fluctuates due to the change of the polarization state due to the fluorite, and the exposure of the wafer W is performed based on the detection result of the light amount monitor 5. The light quantity cannot be controlled to be substantially constant during the exposure.
- the present inventors have found that the change in the polarization state of an optical material such as fluorite changes in the birefringence of the optical material itself such as fluorite. Ki was found to be the cause.
- the present inventors have found that although the amount of fluctuation of birefringence in optical materials such as fluorite varies among individuals, the fluctuation of birefringence in almost all currently available optical materials such as fluorite crystals. It was found that this phenomenon was inevitable, and consequently the phenomenon of polarization state fluctuation was inevitable.
- FIG. 8 is a graph in which the variation with respect to the sensor output immediately after the start of irradiation is expressed in% as a result of continuous irradiation of an ArF excimer laser at a frequency of lkHz and a fluence of 10 mJ Zcm 2 .
- the exposure light amount is formed in the optical path between the light source 1 and the beam splitter 5a and formed of fluorite.
- fluorite whose variation in birefringence when the illumination light enters under the use conditions is 3 nmZcm or less is used.
- the change in the polarization state caused by the change in the birefringence of the fluorite can be reduced, the polarization state of the light incident on the beam splitter 5a can be stabilized.
- the detection light amount of the light amount monitor 5 hardly fluctuates due to the change of the polarization state due to the fluorite, and the exposure light amount for the wafer W is almost constant during the exposure based on the normal detection result of the light amount monitor 5. Control, and good exposure can be achieved.
- the operating conditions are as follows: a wavelength range of 250 nm or less, 0.1 lmjZcm 2 / palm The energy density (fluence) range of the Sou 150nijZcm 2 Z pulse, and the pulse frequency range of 0.1 kHz to 100 MHz.
- the fluorite is disposed in the optical path between the light source 1 and the beam splitter 5a.
- the focus is on the light transmitting member to be formed.
- various modifications can be made to the arrangement position of the beam splitter 5a. In general, a change in the polarization state of light in an exposure apparatus is an unfavorable phenomenon in various aspects. Therefore, regardless of the arrangement position, it is preferable to use fluorite as the light transmitting member to be formed of fluorite, which has a small birefringence variation amount.
- a light transmitting member to be formed of fluorite.
- the invention is not limited to fluorite, but also applies to other suitable optical materials such as fluoride crystals such as barium fluoride, lithium fluoride, sodium fluoride and strontium fluoride. Can be applied.
- the optical material according to the present invention is not limited to the fluoride crystal, and it is possible to use quartz glass or quartz, and it is possible to use an optical member composed of a fluoride crystal, quartz glass and quartz in combination. You can use it.
- the power using the KrF excimer laser light source or the ArF excimer laser light source as the light source is not limited to this.
- the present invention can also be applied to other appropriate light sources such as two laser light sources.
- the birefringence of the fluoride crystal material is reduced.
- the variation is set within a predetermined range.
- the light transmitting member formed of the fluoride crystal material may be kinematically held using, for example, a technique disclosed in US Patent Publication US2002Z0163741A (or WO02Z16993). . This makes it possible to further reduce the birefringence fluctuation of the fluoride crystal material.
- a method of filling the optical path between the projection optical system and the photosensitive substrate with a medium (typically, a liquid) having a refractive index greater than 1.1 that is, a so-called liquid immersion method Apply the law May be used.
- all the optical members disposed therein need not be the optical members having the optical material force according to the present invention. It is preferable that the sum of the optical path lengths in the optical member composed of the optical system is 70% or more of the sum of the optical path lengths in all the optical members constituting the optical system. % Is particularly preferable.
- the optical system of the present invention may be used for both the projection optical system and the illumination optical system, or the projection optical system.
- the object to which the optical system of the present invention is applied is not limited to an exposure apparatus, and is suitably adopted for various inspection apparatuses and measurement apparatuses using light having a wavelength of 250 nm or less.
- a mask (reticle) is illuminated by an illumination optical device (illumination step), and a transfer pattern formed on the mask is projected onto a photosensitive substrate using a projection optical system.
- exposing exposure step
- a micro device semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.
- an example of a method for obtaining a semiconductor device as a microdevice by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of the above-described embodiment will be described. This will be described with reference to FIG.
- a metal film is deposited on one lot of wafers.
- a photoresist is applied on the metal film on the one lot wafer.
- the image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of the lot through the projection optical system.
- the photoresist on the one lot wafer is developed, and in step 305, the resist pattern is etched on the one lot wafer using the resist pattern as a mask, thereby forming a pattern on the mask.
- the circuit pattern force corresponding to each is formed in each shot area on each wafer.
- a device such as a semiconductor element is manufactured by forming a circuit pattern of a further upper layer and the like.
- a semiconductor device manufacturing method a semiconductor device having an extremely fine circuit pattern can be obtained with good throughput.
- a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). .
- a predetermined pattern circuit pattern, electrode pattern, etc.
- a so-called optical lithography step of transferring and exposing a mask pattern onto a photosensitive substrate (a glass substrate coated with a resist) using the exposure apparatus of the above-described embodiment is executed.
- a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate.
- the exposed substrate is subjected to various processes such as a developing process, an etching process, a resist stripping process, etc., so that a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming process 402.
- a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix, or R, G,
- a color filter is formed by arranging a plurality of sets of filters of three stripes B in the horizontal scanning line direction.
- a cell assembling step 403 is performed.
- a liquid crystal panel liquid crystal cell
- a liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402, Manufacture panels (liquid crystal cells). Thereafter, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, a liquid crystal display element having an extremely fine circuit pattern can be obtained with a high throughput.
- the method for producing an optical system according to the present invention is a method for producing an optical system using light having a wavelength of 250 nm or less as transmitted light
- the method of manufacturing an exposure apparatus includes an illumination optical system for illuminating a mask using light having a wavelength of 250 nm or less, and a projection for projecting and exposing a pattern image of the mask onto a substrate to be exposed.
- an illumination optical system for illuminating a mask using light having a wavelength of 250 nm or less
- a projection for projecting and exposing a pattern image of the mask onto a substrate to be exposed.
- the specific method for selecting the optical member made of the optical material according to the present invention is as described above.
- the optical system or various members required for the exposure apparatus other than the optical member made of the optical material according to the present invention and various members generally used for the optical system or the exposure apparatus to which the present invention is applied.
- a member is appropriately used.
- there is no particular limitation on a method of assembling various members necessary for such an optical system or an exposure apparatus together with the optical member made of the optical material according to the present invention and a general method for assembling the optical system or the exposure apparatus is used. Is appropriately adopted.
- the present invention also provides a step-and-scan type scanning projection exposure apparatus (US Pat. No. 5,473,410) for synchronously moving a reticle and a wafer to expose a reticle pattern.
- the present invention can be applied not only to a stepper, but also to a step-and-repeat type exposure apparatus (stepper) that exposes a reticle pattern while the reticle and wafer are stationary and sequentially moves the wafer.
- the present invention is also applicable to a twin-stage type exposure apparatus.
- Twin stage type The structure and exposure operation of the exposure apparatus are described in, for example, JP-A-10-163099 and JP-A-10-214783 (corresponding US Pat. Nos. 6,341,007, 6,400,441, 6,549,269 and 6). , 590,634), JP 2000-505958 (corresponding US Pat. No. 5,969,441) or US Pat. No. 6,208,407 [disclosed!
- the present invention provides a liquid immersion light device that locally fills a liquid between a projection optical system and an object to be exposed, and a liquid that moves a stage holding a substrate to be exposed in a liquid tank.
- the present invention is also applicable to an immersion exposure apparatus and a liquid immersion exposure apparatus in which a liquid tank having a predetermined depth is formed on a stage and a substrate is held therein.
- Japanese Patent Application Laid-Open No. 6-124873 discloses a method in which a liquid tank having a predetermined depth is formed on a stage.
- An immersion exposure apparatus for holding a substrate therein is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-303114 and US Pat. No. 5,825,043.
- the optical members having the optical material strength that is effective in the present invention are selectively disposed and arranged.
- an exposure apparatus using an ArF excimer laser light source, a KrF excimer laser light source, or the like the polarization of light incident on a beam splitter disposed in the optical path is improved.
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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)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Abstract
Description
Claims
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JP2003-338666 | 2003-09-29 | ||
JP2003338666A JP2007012637A (ja) | 2003-09-29 | 2003-09-29 | 光学材料、光学部材、光学系、露光装置、および露光方法 |
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WO2005031821A1 true WO2005031821A1 (ja) | 2005-04-07 |
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PCT/JP2004/014149 WO2005031821A1 (ja) | 2003-09-29 | 2004-09-28 | 光学系、露光装置、およびそれらの製造方法 |
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Cited By (1)
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KR20170117595A (ko) * | 2015-02-24 | 2017-10-23 | 프라운호퍼 게젤샤프트 쭈르 푀르데룽 데어 안겐반텐 포르슝 에. 베. | 전자 회로를 갖는 반사기 및 반사기를 갖는 안테나 장치 |
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CN112996853B (zh) * | 2018-11-14 | 2023-10-27 | 信越化学工业株式会社 | 固化性氟聚醚系橡胶组合物和光学部件 |
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JPH0912324A (ja) * | 1995-06-29 | 1997-01-14 | Nikon Corp | 紫外線照射による歪が抑制された石英ガラス部材 |
JPH1154411A (ja) * | 1997-07-29 | 1999-02-26 | Canon Inc | 投影光学系及びそれを用いた投影露光装置 |
JPH11116248A (ja) * | 1997-10-13 | 1999-04-27 | Nikon Corp | 合成石英ガラス部材 |
WO2002029492A1 (en) * | 2000-10-03 | 2002-04-11 | Corning Incorporated | Photolithography methods and systems |
JP2003221245A (ja) * | 2002-01-31 | 2003-08-05 | Shinetsu Quartz Prod Co Ltd | ArF露光装置用合成石英ガラス素材 |
-
2003
- 2003-09-29 JP JP2003338666A patent/JP2007012637A/ja active Pending
-
2004
- 2004-09-28 WO PCT/JP2004/014149 patent/WO2005031821A1/ja not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH0912324A (ja) * | 1995-06-29 | 1997-01-14 | Nikon Corp | 紫外線照射による歪が抑制された石英ガラス部材 |
JPH1154411A (ja) * | 1997-07-29 | 1999-02-26 | Canon Inc | 投影光学系及びそれを用いた投影露光装置 |
JPH11116248A (ja) * | 1997-10-13 | 1999-04-27 | Nikon Corp | 合成石英ガラス部材 |
WO2002029492A1 (en) * | 2000-10-03 | 2002-04-11 | Corning Incorporated | Photolithography methods and systems |
JP2003221245A (ja) * | 2002-01-31 | 2003-08-05 | Shinetsu Quartz Prod Co Ltd | ArF露光装置用合成石英ガラス素材 |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20170117595A (ko) * | 2015-02-24 | 2017-10-23 | 프라운호퍼 게젤샤프트 쭈르 푀르데룽 데어 안겐반텐 포르슝 에. 베. | 전자 회로를 갖는 반사기 및 반사기를 갖는 안테나 장치 |
CN107548527A (zh) * | 2015-02-24 | 2018-01-05 | 弗劳恩霍夫应用研究促进协会 | 具有电子电路的反射器和具有反射器的天线装置 |
KR101952168B1 (ko) | 2015-02-24 | 2019-02-26 | 프라운호퍼 게젤샤프트 쭈르 푀르데룽 데어 안겐반텐 포르슝 에. 베. | 전자 회로를 갖는 반사기 및 반사기를 갖는 안테나 장치 |
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