TW201940986A - Exposure device and exposure method - Google Patents

Abstract

This exposure device (EX) is provided with: a first illumination optical system having a wavelength selection part (6A, 6B, 6C) that allows entry of light from a light source (2A, 2B, 2C) for generating light including a plurality of emission line wavelengths (g line, h line, i line, and the like) in order to illuminate a mask substrate M and that extracts an illumination light flux including at least a specific one emission line wavelength (i line) of the plurality of emission line wavelengths, the illumination light flux being limited to a predetermined wavelength width, and having a numerical aperture variable part (8A, 8B, 8C) that adjusts the spread angle of the illumination light flux; and a second illumination optical system (ILn) that includes an optical integrator (fly-eye lens system FEn) for irradiating, with the illumination light flux, the mask substrate at uniform illuminance with a numerical aperture corresponding to the spread angle. The wavelength selection part is mounted with a first wavelength selection element (interference filter SWb) that excludes an emission line on the short wavelength side and excludes an emission line on the long wavelength side appearing next to the specific emission line wavelength (i line), and that extracts a spectral component of the specific emission line wavelength and extracts a low-brightness spectral component distributed in a skirt of the specific emission line wavelength.

Description

Exposure device and exposure method

The present invention relates to an exposure apparatus and method for transferring a pattern of a photomask to a substrate.

In the past, in a photolithography step for manufacturing electronic components such as a liquid crystal display element, a semiconductor element, and a thin-film magnetic head, the following exposure device was used, which irradiates illumination light from a light source to a transmissive or reflective photomask substrate. The transmitted light or reflected light from the element pattern (pattern for electronic components) formed on the photomask substrate is projected and exposed on a substrate to be exposed such as a plate coated with a photosensitive agent such as a photoresist through a projection optical system. As a conventional exposure device, for example, it is known to disclose, for example, Japanese Patent Application Laid-Open No. 2012-049332, and an illumination system (lighting device) is provided in which each illumination light from a light source unit such as two mercury lamps is collected into a circular shape at the entrance side. In addition, after the bundled optical fibers gathered into a rectangular (slit-shaped) exit side are synthesized, the slit-shaped illumination area on the mask substrate is uniformly distributed by the integrator included in the fly-eye lens optical system and the like. Le lighting.

When a mercury lamp (ultra-high-pressure mercury discharge lamp, etc.) is used as the light source, the arcing light of the mercury lamp includes a plurality of bright lines, and a specific bright line wavelength is selected as the illumination light for the exposure (illumination light of the mask substrate). In the photolithography step, taking into account the photosensitive wavelength characteristics of the photoresist and the optical properties (resolution, chromatic aberration characteristics) of the projection optical system, the g-rays in the ultraviolet wavelength range of the bright line wavelength of the mercury lamp (the central wavelength is 435.835 nm), h-ray (center wavelength is 404.656 nm), i-ray (center wavelength is 365.015 nm). The resolution R, which is represented by the minimum line width value capable of projection exposure, is that the numerical aperture of the image side (the exposed substrate side) of the projection optical system is set to NAp, the wavelength of the illumination light is set to λ (nm), and the program constant When k (0 <k ≦ 1), it is defined by R = k · (λ / NAp). Therefore, by using the shortest i-ray among the three bright-line wavelengths, it is possible to perform projection exposure (high-resolution exposure) of a finer mask pattern. However, in recent years, compared with the positive type, the exposure steps for the negative-type negative photoresist layer (light-sensing layer) have increased. Therefore, it is necessary to set a longer exposure time, and there is concern about per unit of the substrate being exposed. Decrease in the number of pieces processed over time (decrease in productivity).

According to a first aspect of the present invention, there is provided an exposure device that exposes a pattern of a photomask to a light-sensitive substrate and includes a light source that generates a light beam including a plurality of bright-line wavelengths for illuminating the photomask. Light; a first illumination optical system having a wavelength selection for irradiating light from the light source and extracting an illumination beam containing at least one specific bright-line wavelength of the plurality of bright-line wavelengths to a predetermined wavelength width And a numerical aperture variable unit that adjusts the divergence angle of the illumination beam; and a second illumination optical system including an optical integrator that enters the illumination beam whose divergence angle is adjusted, corresponding to the divergence angle. The numerical aperture is used to irradiate the illumination light beam onto the photomask with the same illuminance; and a first wavelength selection element is mounted on the wavelength selection section, and one side of the long wavelength side bright line and The bright line on the short wavelength side is removed, and the spectral components of the specific bright line wavelength and the low The spectral components of the extraction.

According to a second aspect of the present invention, an exposure method is provided, which exposes a pattern of a photomask to a light-sensitive substrate, and includes the following steps: selecting a wavelength in a manner that generates a plurality of bright-line wavelengths with The peak-shaped spectral components of at least one specific bright-line wavelength in the light coming from the light source of the light will not include the bright-line on the long wavelength side and the short-wavelength side appearing beside the specific bright-line wavelength. Bright line, and extract the low-brightness spectral components distributed near the bottom of the specific bright-line wavelength; and illuminate the illumination beam of the spectral component selected by the wavelength with the same illuminance on the photomask, and pass through the low-brightness A specular projection method that does not produce chromatic aberration in the wavelength width of the spectral component, or a reflective optical system in which the chromatic aberration is corrected in the wavelength width of the low-brightness spectral component, and exposes the pattern of the mask on the substrate. .

According to a third aspect of the present invention, there is provided an exposure method that uses light from a light source device including a light beam having a spectral distribution of a specific light beam wavelength selected by a wavelength selection unit, by using illumination optics. The system irradiates a mask carrying a pattern for electronic components, and uses a projection optical system that projects the exposure light beam generated by the mask to project and expose the image of the pattern onto a light-sensitive substrate, including: The above-mentioned wavelength selection unit extracts the light of the first spectral distribution and the light of the second spectral distribution having different wavelength bands from the light generated by the light source device; and using the illumination optical system to perform Kohler on the photomask. Illumination, and on the pupil plane in the illumination optical system, the first light source image distributed in the two-dimensional range due to the light of the first spectral distribution and the two-dimensional range due to the light in the second spectral distribution The distributed second light source images are formed to overlap.

According to a fourth aspect of the present invention, there is provided an exposure method that uses a predetermined wavelength distribution of illumination light to illuminate a mask pattern, and projects an imaging beam generated by the mask pattern into a projection on a substrate. An optical system, and projecting and exposing the image of the mask pattern on the substrate includes: setting a specific center wavelength in the wavelength distribution of the illumination light as λ; and setting a numerical aperture on the substrate side of the projection optical system. Is a square or rectangle with NAp and a program constant set to k (0 <k ≦ 1), which is close to the smallest resolvable minimum line width dimension determined by the resolution R defined by k · (λ / NAp) When the projection image of the hole pattern is projected on the substrate, the ratio of the short axis length to the long axis length of the projection image of the hole pattern deformed into an ellipse is 80% or more, and more preferably 90% or more. The width of the wavelength distribution of the above-mentioned illumination light including the above-mentioned central wavelength λ; and the mask having the pattern for the electronic component formed by the illumination light of the wavelength distribution of the above-mentioned set width Line lighting, projection exposure on the substrate with the electronic component pattern.

A preferred embodiment of the exposure apparatus according to the aspect of the present invention will be described in detail below with reference to the accompanying drawings. In addition, the form of the present invention is not limited to these embodiments, and includes various changes or improvements. That is, the constituent elements described below include those that can be easily imagined by those with ordinary knowledge in the technical field to which the present invention pertains, and those that are substantially the same, and the constituent elements described below can be appropriately combined. In addition, various omissions, substitutions, or changes of the constituent elements can be made without departing from the gist of the present invention.

[First Embodiment]
FIG. 1 is a perspective view showing a schematic overall configuration of the scanning projection exposure apparatus EX according to the first embodiment, and FIG. 2 is a diagram showing the arrangement of optical components of a part of the projection optical system PLn incorporated in the projection exposure apparatus EX of FIG. 1. Illustration. In FIG. 1 and FIG. 2, the direction in which the Z axis of the orthogonal coordinate system XYZ extends indicates the direction of gravity, and the direction in which the X axis extends indicates the plate P and the mask substrate M as the exposed substrate (photosensitive substrate) for scanning. The scanning movement direction in which the exposure moves and the direction in which the Y axis extends indicates the stepwise movement direction of the plate P. The projection exposure device EX of this embodiment is a projection optical system including six partial projection optical systems PL1 to PL6 including a reflection and refraction method, and a flat mask substrate M and a light-sensitive layer (photoresist, etc.) are coated on one side. The plate-shaped plate P is moved synchronously in the X direction, and an image of a pattern for electronic components formed on the photomask substrate M is transferred to the exposure device of the step-and-scan method of the plate P for explanation. The projection exposure device EX shown in FIG. 1 and FIG. 2 has the same structure as disclosed in, for example, International Publication No. 2009/128488 or Japanese Patent Application Publication No. 2010-245224. The description of the device configuration is simple.

[Configuration of projection optical system]
The six illumination areas IA1 to IA6 (refer to FIG. 1) set on the reticle substrate M are respectively set to a rectangular shape having a shorter size in the scanning direction, that is, in the X direction than in the stepwise moving direction, that is, in the Y direction. For each of the illumination areas IA1 to IA6, illumination light for exposure adjusted to a uniform illumination distribution (for example, uniformity within ± 5%) is projected by an illumination device described later. The six illumination areas IA1 to IA6 are respectively set at positions on the respective object surface sides of the six partial projection optical systems PL1 to PL6. For example, if a pattern portion of the mask substrate M appears in the illumination area IA1, the transmitted light generated by the pattern portion is reflected on a reflecting surface on the upper side of the 稜鏡 PMa and enters a part of the projection optical system PL1. Part of the projection optical system PL1 transmits the transmitted light (imaging beam, exposure beam) from the pattern part, as shown in FIG. 2, through the lens system Ga1, Ga2, Ga3, and the concave mirror Ga4, which are arranged along the optical axis AXa. 1 imaging system PL1a reflects on the reflecting surface on the lower side of 稜鏡 PMa, thereby imaging on the intermediate image plane IM1 as an intermediate image of the illumination area IA1 at equal magnification.

On the intermediate image plane IM1, as shown in FIG. 1, a field diaphragm plate FA1 having trapezoidal openings inclined at both end edges in the Y direction is arranged. The imaging beam transmitted through the opening of the field diaphragm plate FA1 is reflected on the reflecting surface on the upper side of 稜鏡 PMb. As shown in FIG. 2, it passes through a lens system Gb1, Gb2, Gb3, The second imaging system PL1b of the concave mirror Gb4 reflects on the reflecting surface on the lower side of 稜鏡 PMb in the direction of the plate P (-Z direction). Thereby, in the trapezoidal projection area EA1 set on the plate P, the intermediate image formed in the opening portion of the field diaphragm plate FA1 is re-imaged and imaged at equal magnification. Part of the projection optical system PL1 uses the first imaging system PL1a and the second imaging system PL1b to form an image of a pattern portion in the illumination area IA1 in the projection area EA1, and telecentrically image the relationship of equal orthographic images.

As shown in FIG. 2, the first imaging system PL1a is a half-field type imaging system configured with a reflection and refraction method of a concave mirror Ga4 on the pupil plane Epa, and the second imaging system PL1b is also configured with a concave mirror Gb4 on the pupil plane Epb. Half-field type imaging system with reflection and refraction. The pupil surfaces Epa and Epb optically form a conjugate relationship with each other. A light source image (secondary light source image) is formed on each of the pupil surfaces Epa and Epb, and is formed in an illumination device that illuminates the illumination area IA1. In addition, in the imaging optical path of the partial projection optical system PL1, a focus adjustment optical member FC1 is provided between the mask substrate M and 稜鏡 PMa, which is used to focus the image in the projection area EA1 projected on the plate P. (Focus state) Make fine adjustments. Further, an image-shifting optical member SC1 is provided between the field diaphragm plate FA1 and 稜鏡 PMb, and is used to independently position the projection area EA1 projected on the plate P in the X direction and the Y direction, respectively. Adjustment; and a magnification adjustment optical member MC1 is provided between the 稜鏡 PMb and the plate P, which is used to finely adjust the size of the image of the pattern portion projected in the projection area EA1 within a range of about several tens of ppm. The focus adjustment optical member FC1, the image shift optical member SC1, and the magnification adjustment optical member MC1 are disclosed in, for example, International Publication No. 2013/094286, and therefore detailed descriptions of the configuration or function are omitted.

In this embodiment, as shown in FIG. 2, the partial projection optical system PL1 includes a first imaging system PL1a, a second imaging system PL1b, 稜鏡 PMa, PMb, a field diaphragm plate FA1, a focus adjustment optical member FC1, and image deviation. The shift optical member SC1 and the magnification adjusting optical member MC1 are configured similarly to the other projection optical systems PL2 to PL6. Therefore, the other partial projection optical systems PL2 to PL6 also form images of the pattern portion of the mask substrate M at equal magnifications in each of the trapezoidal projection areas EA2 to EA6 set on the plate P. Therefore, if the photomask substrate M and the plate P are moved one-dimensionally at the same speed in the X direction to perform scanning exposure, each of the six projection areas EA1 to EA6 is exposed on the light-sensing layer of the plate P. The pattern part is spliced in the Y direction. In addition, when no special distinction is required, the partial projection optical systems PL1 to PL6, the illumination areas IA1 to IA6, and the projection areas EA1 to EA6 described above are also referred to as partial projection optical systems PLn, illumination areas IAn, and projection, respectively. Area EAn (n = 1 to 6).

[Configuration of Lighting Device]
FIG. 3 is a perspective view showing a schematic overall configuration of an illumination device for projecting exposure illumination light to each of the six illumination areas IA1 to IA6 set on the mask substrate M. The orthogonal coordinate system XYZ is set to be the same as the above. Figures 1 and 2 are the same. In the lighting device of this embodiment, as disclosed in Japanese Patent Application Laid-Open No. 2010-245224, three mercury lamps (short-arc type ultra-high-pressure mercury discharge lamps) 2A, 2B, and 2C (light source devices) of the same specification are used as light sources. . The number of lamps in the light source device is determined based on the number of partial projection optical systems PLn so that the illumination light projected on each of the illumination areas IAn becomes the required illuminance value, but it is only required to be two or more. Ultra-high-pressure mercury discharge lamps produce g-rays (wavelength 435.835 nm) and h-rays with high brightness in the ultraviolet wavelength region by setting the vapor pressure of mercury enclosed in the discharge tube to 10 ⁶ Pa (Pascal) or higher. (Wavelength 404.656 nm), i-ray (wavelength 365.015 nm). The respective light emitting points (arc discharge parts) of the mercury discharge lamps 2A, 2B, and 2C are respectively arranged at the positions of the first focal points of the elliptical mirrors 4A, 4B, and 4C, and on the reflecting surfaces inside the respective elliptical mirrors 4A, 4B, and 4C The reflected light beam BM is condensed (converged) toward the position of the second focal point of each of the elliptical mirrors 4A, 4B, and 4C.

The light beams BM emitted from the elliptical mirrors 4A, 4B, and 4C in the -Z direction are separated in the following manner: With the dichroic mirror DM disposed immediately before the second focus, the spectral component of the ultraviolet wavelength region for exposure (for example, 460) The short wavelength region below nm) reflects in the + X direction, and the spectral components of the longer wavelength region are transmitted. The light beams in the ultraviolet wavelength range for the exposure reflected by each of the dichroic mirrors DM are at the positions of the second focal points of the elliptical mirrors 4A, 4B, and 4C, and the beam diameter becomes the thinnest. Rotary shutters 5A, 5B, 5C. The light beams in the ultraviolet wavelength range for exposure through which each of the rotating shutters 5A, 5B, and 5C pass are diverged and incident on the wavelength selection sections 6A, 6B, and 6C, respectively. Each of the wavelength selection sections 6A, 6B, and 6C is provided with a plurality of lens elements and a wavelength selection interference filter, and transmits only a required bright-line wavelength portion of the light beam in the ultraviolet wavelength region for exposure. Each of the interference filters provided in the wavelength selection sections 6A, 6B, and 6C can be set according to the fineness (resolution) of the pattern of the reticle substrate M to be exposed, or can be given to the light sensing layer of the plate P. Exposure (dose), and exchange (switch) with several people with different wavelength selection characteristics. The difference in the wavelength selection characteristics of the interference filter will be described in detail later, but the wavelength characteristics (wavelength distribution) of the exposure illumination light projected in the illumination area IAn on the mask substrate M can be switched to be suitable Characteristics for pattern exposure with higher resolution and characteristics suitable for pattern exposure with increased illuminance in order to improve productivity. For this reason, the interference filter is prepared in advance to have the following characteristics: the characteristic of transmitting any bright-line wavelength component of g-rays (wavelength 435.835 nm), h-rays (wavelength 404.656 nm), and i-rays (wavelength 365.015 nm); Characteristics of transmitting two consecutive bright-line wavelength components (g-ray + h-ray, or i-ray + h-ray) among g-ray, h-ray, and i-ray; or all bright-line wavelengths of g-ray, h-ray, and i-ray Characteristics of component transmission.

The light beams emitted from each of the wavelength selection sections 6A, 6B, and 6C are incident on the variable magnification sections 8A, 8B, and 8C. The variable magnification sections 8A, 8B, and 8C are used to divide the light distribution section 10 to the subsequent stage. Numerical aperture (maximum inclination angle of the main light) or diameter (diameter of the main light rays) of the three illumination fiber beams (optical fibers, light transmission elements) 12A, 12B, and 12C on the incident side ) Make adjustments. Each of the variable magnification sections 8A, 8B, and 8C is provided with a plurality of lens elements. The numerical apertures (NA) of the illumination beams BMa, BMb, and Bmc that are incident on each of the optical fiber bundles 12A, 12B, and 12C are constant. Continuous adjustment within the range, but can move in the direction of the optical axis. With each of the variable magnification units 8A, 8B, and 8C, as a result, the light from the light source images (secondary light source images) distributed on the pupil surfaces Epa and Epb of the partial projection optical system PLn shown in FIG. 2 can be obtained. The radial dimensions from the axes AXa and AXb are continuously changed. That is, each of the variable magnification units 8A, 8B, and 8C can set the maximum numerical aperture of the partial projection optical system PLn to NAp, and set the numerical aperture of the illumination beam projected to the illumination area IAn to NAi. The lighting σ value (0 <σ ≦ 1) determined by the ratio of NAi / NAp is adjusted. Therefore, each of the variable magnification sections 8A, 8B, and 8C is also referred to as a numerical aperture variable section capable of continuously adjusting the illumination σ value (the numerical aperture NPi of the illumination beam). In addition, the structures from the elliptical mirror 4A to the variable magnification unit 8A shown in FIG. 3, the structures from the elliptical mirror 4B to the variable magnification unit 8B, and the structures from the elliptical mirror 4C to the variable magnification unit 8C are also collectively referred to. This is the first illumination optical system. Details of its functions are as follows.

The light distribution unit 10 is the second one arranged so that the illumination light beams BMa, BMb, and Bmc, which are incident from each of the three incident side optical fiber bundles 12A, 12B, and 12C, are allocated to correspond to each of the six illumination areas IAn. Each method of the illumination optical systems IL1 to IL6 is divided into six light emitting fiber bundles FG1 to FG6. Each of the second illumination optical systems IL1 to IL6 uses the emitting ends of the optical fiber bundles FG1 to FG6 as light source images (secondary light source images formed by a plurality of point light sources), and each illumination area IAn performs Kohler illumination. In addition, when no special distinction is required, each of the second illumination optical systems IL1 to IL6 and the optical fiber bundles FG1 to FG6 described above is also referred to as the second illumination optical system ILn and the optical fiber bundle FGn (n = 1 to 6).

[First illumination optical system]
FIG. 4 is a perspective view showing the detailed structure of the first illumination optical system arranged on the optical path from the mercury lamp 2A to the incident side fiber bundle 12A shown in FIG. 3, and the orthogonal coordinate system XYZ system is set to be the same as those in FIGS. Figure 3 is the same. The first illumination optical system from the mercury lamp 2B to the incident fiber bundle 12B and the first illumination optical system from the mercury lamp 2C to the incident fiber bundle 12C also have the same configuration as that shown in FIG. 4. As shown in FIG. 4, the light beam BM immediately after exiting from the exit opening (end in the -Z direction) of the elliptical mirror 4A along the optical axis AX1 passes through the opening on the upper side (+ Z direction) of the elliptical mirror 4A. And the lower electrode part of the mercury lamp 2A, it has a ring-shaped intensity distribution centered on the optical axis AX1, that is, a hollow state distribution with extremely low illuminance at the center part. The light beam BM is focused toward the position PS1 of the second focal point of the elliptical mirror 4A arranged on the rotating blade of the rotary shutter 5A, but the arc discharge portion generated between the electrodes of the mercury lamp 2A is elongated in the direction of the optical axis AX1 Therefore, the unfocused light at the position PS1 is spot-shaped and becomes a beam waist with a limited size (diameter).

The wavelength selection section 6A is provided with a lens system (collimation lens) 6A1 that enters a light beam BM diverging and traveling from the position PS1 of the second focal point and converts it into a substantially parallel light beam; a sliding mechanism FX that holds Two interference filters (wavelength selection member, wavelength selection element, band-pass filter) SWa, SWb with mutually different wavelength selection characteristics, and one of the interference filters SWa, SWb is applied to the optical path Switching between the middle and pluggable methods; and the lens system 6A2, which condenses (converges) the light beam BMa transmitted from any of the interference filters SWa, SWb at the focal position PS2 (optically conjugated to the position PS1) Position). The slide mechanism FX has a configuration in which the interference filters SWa and SWb are easily removed or attached, respectively. When using a third interference filter (wavelength selection member, wavelength selection element, bandpass filter) having a wavelength selection characteristic different from that of any of the interference filters SWa, SWb, it is only necessary to rotate In a state where the shutter 5A blocks the light beam BM from the mercury lamp 2A, any one of the interference filters SWa and SWb may be removed from the slide mechanism FX, and a third interference filter may be installed instead. In addition, when a sliding mechanism is not provided, a mounting mechanism that can easily detach the interference filters SWa, SWb and the like is mounted.

The light beam BMa emitted from the wavelength selection section 6A becomes a beam waist at the focal position PS2, and then enters the variable magnification section 8A in a divergent state. At the focus position PS2, a circular light source image caused by a blurred image of the arc discharge portion (light emitting point) of the mercury lamp 2A is formed. The magnification variable section 8A includes two lens systems 8A1 and 8A2 that can adjust the position along the optical axis AX1. With the lens systems 8A1 and 8A2, the light beam BMa diverging and traveling from the focal position PS2 is projected with a predetermined beam diameter or a predetermined numerical aperture, and is focused on the incident end FBi of the fiber bundle 12A on the incident side. The incident end FBi of the fiber bundle 12A is basically arranged so as to be optically conjugated to the focal position PS2, but it can also be deliberately released by adjusting the position of the lens systems 8A1 and 8A2 of the variable magnification section 8A. Its conjugate relationship. The two lens systems 8A1 and 8A2 function as a variable magnification relay system. As the numerical aperture of the illumination beam BMa changes, as a result, the diameter of the beam BMa on the incident end FBi of the optical fiber bundle 12A is relative to the incident end. The effective maximum diameter of FBi becomes smaller or larger.

[Wavelength selection by interference filter]
Here, an example of wavelength selection by an interference filter that can be mounted on the sliding mechanism FX of the wavelength selection section 6A will be described with reference to FIGS. 5 to 8. FIG. 5 is a graph schematically showing an example of a wavelength characteristic (spectral distribution) of a light beam BM generated by arc discharge of a mercury lamp (ultra-high-pressure mercury discharge lamp). 6 is a diagram schematically showing a state in which light with a narrow wavelength width including i-rays is selected from the spectral distribution of FIG. 5 by the i-ray-narrow-band interference filter SWa. FIG. 7 is a diagram schematically showing The i-ray-broadband interference filter SWb is used to select a graph from the spectral distribution of FIG. 5 for extracting a relatively wide-wavelength light state including the i-ray and the low-luminance portion near the bottom thereof, and FIG. 8 Schematic representation of i-ray + h-ray-interference filter SWc (third interference filter) is used to extract light with a wide wavelength width including both i-ray and h-ray from the spectral distribution of FIG. 5 Status chart. In any of the graphs in FIGS. 5 to 8, the horizontal axis represents the wavelength (nm), and the vertical axis represents the relative intensity (%). In addition, in the wavelength characteristics (spectral distribution) of the light beam BM from the ultrahigh-pressure mercury discharge lamp shown in FIG. 5 (and FIGS. 6 to 8), the g-rays, h-rays, i-rays, and j-rays are the main bright lines. The respective peak-shaped spectral portions are shown as the wavelength widths when measured using a spectroscope with a wavelength resolution that is not too high. The actual wavelength-width of the peak-shaped spectral portions is at half-height width (which becomes half of the peak intensity). When the width of the intensity is specified, it is about several nm to about ten nm.

In this embodiment, as shown in FIGS. 6 to 8, three types of interference filters SWa, SWb, and SWc are prepared. The i-ray-narrow-band interference filter SWa is shown in FIG. 6 and has the following wavelength selection characteristics: at a wavelength of about 354 nm to about 380 nm, the transmittance becomes more than 10%; and at a wavelength of about 359 Between nm and about 377 nm, the transmittance is more than 90%. Therefore, the full width at half maximum of the wavelength width selected by the i-ray-narrow-band interference filter SWa includes the bright-line wavelength (365.015 nm) of the i-ray and becomes approximately 22 nm. In addition, as shown in FIG. 7, the i-broadband interference filter SWb has the following wavelength selection characteristics: the transmittance becomes more than 10% at a wavelength of about 344 nm to about 398 nm; Between about 350 nm and about 395 nm, the transmittance is more than 90%. Therefore, the full width at half maximum of the wavelength width selected by the i-ray-broadband interference filter SWb includes the bright line wavelength (365.015 nm) of the i-ray and becomes approximately 49 nm. Both the i-ray-narrow-band interference filter SWa and the i-ray-broadband interference filter SWb only select the bright-line wavelength band of the i-ray as the illumination light for exposure, but the i-ray-narrow-band interference filter SWa The bandwidth of the wavelength selection is narrow, so the monochromaticity of the i-ray (narrow) indicated by the oblique line portion in FIG. 6 is more than that indicated by the oblique line portion in FIG. 7 selected by the i-ray-broadband interference filter SWb. The i-ray (wide) becomes good, the influence caused by the chromatic aberration characteristic of the partial projection optical system PLn is reduced, and pattern analysis with higher resolution can be performed.

However, compared with the i-ray (wide) light amount (area of the oblique line in FIG. 7) obtained by the i-ray-broadband interference filter SWb, the i-ray-narrow-band interference filter SWa The light amount of the i-ray (narrow) (the area of the oblique line in FIG. 6) is small. Therefore, it is necessary to slightly reduce the moving speed of the mask substrate M and the plate P during scanning exposure, resulting in a decrease in productivity. In contrast, the i-ray (wide) obtained by the i-ray-broadband interference filter SWb includes a low value from the bright-line wavelength (365.015 nm) of the i-ray to the h-ray located beside the long-wavelength side. The spectral components near the bottom of the brightness and the low-brightness near the bottom of the relatively strong peak wavelength near the short wavelength side, so that high-resolution pattern exposure can be performed while increasing the amount of light A few percent or more can improve productivity. The bandwidth selected by the wavelength of the i-broadband interference filter SWb (in terms of FWHM, approximately 49 nm) is the minimum line width of the pattern projection image obtained based on the chromatic aberration characteristics of the partial projection optical system PLn The contrast value is determined. The chromatic aberrations of some projection optical systems PLn include magnification (horizontal) chromatic aberration and on-axis (vertical) chromatic aberration. For example, in a projection optical system dedicated to only the bright-line wavelength of i-rays, it is corrected to have the following tendency (the tendency of a quadratic function) The chromatic aberration characteristic: the amount of chromatic aberration becomes approximately zero at the bright-line wavelength of the i-ray, and the amount of aberration increases at the short-wavelength side and the long-wavelength side more than that. Furthermore, in a projection optical system that allows the use of two bright-line wavelengths of i-rays and h-rays, the chromatic aberration characteristic is corrected to have a color difference amount of approximately zero at a wavelength approximately between the i-rays and the h-rays, and Reduce the rate of change of the amount of chromatic aberration between the bright-line wavelengths of the i-ray and the h-ray.

When two bright-line wavelengths of i-ray and h-ray are used, the i-ray + h-ray-interference filter SWc is mounted on the sliding mechanism FX, and the light with the spectral distribution shown by the oblique line portion in FIG. 8 is used i-ray + h-ray. The i-ray + h-ray-interference filter SWc is shown in FIG. 8 and has the following wavelength selection characteristics: the transmittance becomes more than 10% at a wavelength of about 344 nm to about 420 nm; and the wavelength is about 350 Between nm and about 415 nm, the transmittance is more than 90%. Therefore, the full width at half maximum of the wavelength width selected by the i-ray + h-ray-interference filter SWc includes the bright-line wavelength (365.015 nm) of the i-ray and the bright-line wavelength (404.656 nm) of the h-ray and becomes approximately 70 nm. In pattern exposure using two bright-line wavelengths of i-ray and h-ray, compared with pattern exposure using only i-ray, the smallest resolvable line width becomes larger, but i-ray + h-ray-interference filter SWc If the obtained i-ray + h-ray light amount (area of the oblique line in FIG. 8) is the same as that of the i-ray-narrowband interference filter SWa of FIG. 6 or the i-ray-broadband interference filter SWb of FIG. 7 Compared with this, it is overwhelmingly increased, and productivity is greatly improved. Therefore, when the pattern of the photomask substrate M which is projected and exposed on the light-sensing layer of the plate P does not include a pattern with a critical line width of high fineness, the i-ray + h-ray-interference filter SWc is used. , Can be pattern exposure with high productivity.

[Light distribution section 10]
FIG. 9 schematically shows the overall configuration of the optical fiber bundle as the light distribution section 10 provided in the lighting device shown in FIG. 3, the shape of the entrance end FBi of each of the optical fiber bundles 12A, 12B, and 12C on the entrance side, and the exit side. The perspective view of the shape of each of the exit ends FBo of the optical fiber bundles FG1 to FG6 is set to the same coordinate system XYZ as in FIG. 3. The incident ends FBi of the optical fiber bundles 12A, 12B, and 12C on the incident side are formed by concentrating a plurality of optical fiber wires into a circular shape with a diameter of the entire end face of tens of mm or more. The plurality of optical fiber wires of each of the optical fiber bundles 12A, 12B, and 12C are connected to the wire distribution unit 10a in the optical distribution unit 10, and are divided so that the six optical fiber bundles FG1 to FG6 each include a substantially equal number of lines. The shape of each of the exit ends FBo of the optical fiber bundles FG1 to FG6 is formed by concentrating a plurality of optical fiber wires into a rectangular shape similar to the shape of the illumination area IAn on the mask substrate M. One optical fiber bundle FGn is gathered so as to include approximately the same number of optical fiber wires from the incident side optical fiber bundles 12A, 12B, and 12C, respectively. For example, in the case where the optical fiber bundles 12A, 12B, and 12C are formed by collecting 120,000 optical fiber wires (a total of 360,000 fibers), one optical fiber bundle FGn is formed by collecting 60,000 optical fiber wires. Approximately every 20,000 of the 60,000 optical fibers of the optical fiber bundle FGn are composed of the optical fibers from the optical fiber bundles 12A, 12B, and 12C on the incident side. In addition, one optical fiber line is a quartz fiber with an outer diameter (cladding) of about 0.2 mm.

An optical fiber line emits a light beam from an emitting end while maintaining a numerical aperture (convergence angle or divergence angle) of a light beam irradiated to an incident end. Therefore, the numerical aperture (convergence angle or divergence angle) when the illumination beam BMa irradiated on the incident end FBi of the fiber bundle 12A becomes the illumination beam BSa from the exit end FBo of the fiber bundle FGn is equal to the numerical value of the illumination beam BMa The aperture is the same. The numerical aperture (convergence angle or divergence angle) when the illumination beam BMb irradiated on the incident end FBi of the fiber bundle 12B becomes the illumination beam BSb from the exit end FBo of the fiber bundle FGn is the same as the illumination beam BMb. The numerical aperture is the same, and the numerical aperture (convergence angle or divergence angle) when the illumination beam Bmc irradiated onto the incident end FBi of the fiber bundle 12C becomes the illumination beam BSc from the exit end FBo of the fiber bundle FGn is the same as the illumination beam Bmc The numerical aperture is the same. Therefore, the numerical apertures (convergence angles) of the illumination light beams BMa, BMb, and Bmc irradiated on the respective incident ends FBi of the optical fiber bundles 12A, 12B, and 12C are set to NAia, NAib, and NAic, and NAia = NAib = In the NAic method, when the variable magnification units 8A, 8B, and 8C shown in Fig. 3 (Fig. 4) are adjusted separately, the illumination beams BSa, BSb, and BSc emitted from the exit end FBo of each fiber bundle FGn are adjusted. Each numerical aperture (divergence angle) becomes the same as each other. When the numerical apertures (convergence angles) NAia, NAib, and NAic of the illumination light beams BMa, BMb, and Bmc are different from each other, and the magnification variable sections 8A, 8B, and 8C are adjusted separately, from each fiber bundle FGn The numerical apertures (divergence angles) of the illumination beams BSa, BSb, and BSc emitted from the emitting end FBo become different values from each other.

[Second illumination optical system ILn]
FIG. 10 is a schematic view showing that the illumination light beams (BSa, BSb, BSc) from the respective emitting ends FBo of the six fiber bundles FGn (FG1 to FG6) shown in FIG. 3 (FIG. 9) are irradiated onto the mask substrate In the perspective view of the configuration of the second illumination optical system ILn (IL1 to IL6) in each illumination area IAn on M, the orthogonal coordinate system XYZ is set to be the same as FIG. 3 or FIG. 9. The second illumination optical system ILn includes a first capacitor lens system CFn (CF1 to CF6), which uses a front side in order to use a plurality of point light source images formed on the exit end FBo of the fiber bundle FGn as the light source images of the Kohler illumination. The position of the focal point is configured in a manner consistent with the output end FBo; the fly-eye lens system FEn (FE1 to FE6) sets the incident surface poi at the position of the focal point behind the capacitor lens system CFn; and the second capacitor lens system CPn (CP1 to CP6 ), In order to set the light source image (secondary light source image) formed on the exit surface epi of the fly-eye lens system FEn as the light source image of Kohler illumination, the position of the front focus is set on the exit surface epi of the fly-eye lens system FEn. The illumination area IAn (IA1 to IA6) is set at the position of the focal point on the rear side.

The capacitor lens system CFn and the capacitor lens system CPn are arranged along an optical axis AX2 parallel to the Z axis. The optical axis AX2 is a geometric center point of the FBo from the rectangular exit end of the fiber bundle FGn, and the fly eye lens system FEn The geometric center point in the XY plane is set by the way. The fly-eye lens system FEn is a plural number of lens elements Le having a rectangular cross-section with the Y direction as the long side and the X direction as the short side when viewed in the XY plane. Each is constructed by joining together in the X direction and the Y direction. A convex surface (spherical lens) having a predetermined focal distance is formed on the incident surface poi side and the exit surface epi side of the lens element Le, respectively. In addition, the exit surface epi of the fly-eye lens system FEn becomes the position of the illumination pupil of the second illumination optical system ILn, and the overall outer shape range in the XY plane of the fly-eye lens system FEn is to include the diameter of the illumination pupil (circular). Way to set.

Furthermore, the exit surface epi of the fly-eye lens system FEn is set to a relationship (imaging relationship) with the optical conjugation of the exit end FBo of the optical fiber bundle FGn, and the entrance surface poi of the fly-eye lens system FEn is set to the illumination area IAn (mask). Patterned surface of the substrate M) Optical conjugate relationship (imaging relationship). Therefore, most of the point light source images formed on the output end FBo of the optical fiber bundle FGn are imaged on the epi side of the respective output surfaces of the plurality of lens elements Le of the fly-eye lens system FEn, and the illumination area IAn is the same as that of the lens element Le. The shape of the cross-section is a shape similar to a rectangle for illumination (imaging).

FIG. 11 (A) and FIG. 11 (B) are diagrams schematically showing states of the illumination light beams in the optical path from the exit end FBo of the optical fiber bundle FGn to the fly-eye lens system FEn shown in FIG. 10. The orthogonal coordinate system is XYZ. The setting is the same as that of FIG. 10. FIG. 11 (A) is a view of the optical path viewed from the Y-axis direction (step moving direction), and FIG. 11 (B) is a view of the optical path viewed from the X-axis direction (scanning moving direction). Here, a fine circular light emitting point (diameter of 0.2 mm or less) of the emission end of the optical fiber line which is the source of each of the illumination beams BSa, BSb, and BSc emitted from the emission end FBo of the fiber bundle FGn shown in FIG. 9 ) As point light (point light source image) SPa, SPb, SPc. Furthermore, the numerical apertures of the illumination beams BSa, BSb, and BSc from the spot lights SPa, SPb, and SPc are the same. Therefore, the divergence angles of the illumination beams BSa, BSb, and BSc from the central rays between the exit end FBo of the fiber bundle FGn and the first capacitor lens system CFn are parallel to the optical axis AX2, and the X and Y directions are the same. Angle θbo.

The illumination light beams BSa, BSb, and BSc from the plurality of spot lights SPa, SPb, and SPc formed on the output end FBo of the optical fiber bundle FGn are passed through the first capacitor lens system CFn, as shown in FIG. 11 (A), As shown in FIG. 11 (B), all of the incident surface poi of the fly-eye lens system FEn are overlapped, and the incident surface poi is illuminated with a uniform illuminance distribution. Therefore, the optical fiber bundle FGn and the first capacitor lens system CFn function as a first optical integrator for the fly-eye lens system FEn.

FIG. 12 is a diagram schematically showing an example of an arrangement of a plurality of point lights (point light source images) SPa, SPb, and SPc formed on the exit end FB of the optical fiber bundle FGn shown in FIG. 11 for each optical fiber line. The coordinate system XYZ is set to be the same as that shown in FIG. 11. Point light (point light source image) SPa represented by a white circle, point light (point light source image) SPb represented by a black circle, and point light (dot circle) Light source images) SPc are respectively arranged in the X direction and the Y direction with the same number and the same distribution. In FIG. 12, the three spot lights SPa, SPb, and SPc are shown as being regularly (periodically) distributed in the XY direction, but are actually densely distributed randomly. As previously exemplified, when the optical fiber bundles 12A, 12B, and 12C on the incident side each contain 120,000 optical fiber lines, the spot lights SPa, SPb, and SPc are randomly distributed on the emission end FBo of the optical fiber bundle FGn, respectively. 20000. As an example, the ratio of the size of the XY direction at the emission end FBo, the ratio of the size of the XY direction of one lens element Le of the fly-eye lens system FEn, and the ratio of the size of the XY direction of the illumination area IAn are all set to about 1: In the case of 3, if the outer diameter of the optical fiber line is set to 0.2 mm, about 143 optical fibers are arranged in the X direction of the emitting end FBo and about 420 optical fibers are arranged in the Y direction (the total is 143 × 420 ≒ 6 Wan Gen). In this case, the size in the X direction of the injection end FBo becomes approximately 28.6 mm (0.2 mm × 143), and the size in the Y direction becomes approximately 84 mm (0.2 mm × 420).

FIG. 13 shows an arrangement of a plurality of point light source images (point lights SPa ', SPb', SPc ') formed on the respective exit surfaces epi of the plurality of lens elements Le constituting the fly-eye lens system FEn shown in FIG. 11. In the state diagram, the orthogonal coordinate system XYZ is set to be the same as that in FIG. 11 (or FIG. 12). In FIG. 13, the plurality of spot lights SPa ', SPb', and SPc 'formed on the exit surface epi of each lens element Le are the plurality of spot lights SPa, SPb, and SPc formed on the exit end FBo of the optical fiber bundle FGn. The imager forms approximately 60,000 spot lights SPa ′, SPb ′, and SPc ′ on each lens element Le. Therefore, on the overall exit surface epi of the fly-eye lens system FEn, the distribution also reaches the number of lens elements Le × number of point lights SPa ′, SPb ′, SPc ′ of about 60,000 degrees.

14 (A) and 14 (B) are diagrams schematically showing states of illumination light in an optical path from the fly-eye lens system FEn shown in FIG. 10 to the illumination area IAn on the mask substrate M, and are orthogonal coordinates. The system XYZ is set to be the same as FIG. 10 (or FIG. 11). FIG. 14 (A) is a view from the X direction (scanning movement direction) of the optical path from the fly-eye lens system FEn to the illumination area IAn, and FIG. 14 (B) is a view from the Y direction (step movement direction). Optical path of the fly-eye lens system FEn to the illumination area IAn. The countless spot lights SPa ', SPb', and SPc 'formed on the exit surface epi of the fly-eye lens system FEn, as shown in FIG. 14 (A), are located at the distance ΔHy farthest from the optical axis AX2 in the Y direction. The spot light beams SPa ', SPb', SPc 'diverge and travel, and the illumination beams BSa', BSb ', and BSc' are parallel beams by the second capacitor lens system CPn, and the central rays (principal rays) from the optical axis In a state where AX2 is tilted from the angle θhy, the whole is projected in the Y direction of the illumination area IAn. The illumination light beams BSa ', BSb', and BSc 'traveling from the other point lights SPa', SPb ', and SPc' arranged in the Y direction on the exit surface epi of the fly-eye lens system FEn are also diverged and passed through the second capacitor lens. The system CPn is also a parallel light beam about the Y direction, and is projected (superimposed) on the entire Y direction of the illumination area IAn.

The countless spot lights SPa ', SPb', and SPc 'formed on the exit surface epi of the fly-eye lens system FEn, as shown in Fig. 14 (B), are located at a distance ΔHx farthest from the optical axis AX2 in the X direction. The spot light beams SPa ', SPb', SPc 'diverge and travel, and the illumination beams BSa', BSb ', and BSc' are parallel beams by the second capacitor lens system CPn, and the central rays (principal rays) from the optical axis In a state where AX2 is tilted from the angle θhx, the whole is projected in the X direction of the illumination area IAn. Illumination light beams BSa ', BSb', and BSc 'traveling from the other point lights SPa', SPb ', and SPc' arranged in the X direction on the exit surface epi of the fly-eye lens system FEn are also diverged and passed through the second capacitor lens. The system CPn similarly becomes a parallel beam with respect to the X direction, and is projected (superimposed) on the entire X direction of the illumination area IAn. Therefore, the fly-eye lens system FEn and the second capacitor lens system CPn function as a second optical integrator that irradiates the illumination area IAn with illumination light having a uniform illuminance distribution.

The maximum inclination angle of the illuminating light beams BSa ', BSb', and BSc 'in the Y direction, i.e., the angle θhy, and the maximum inclination angle of the X direction, i.e., the angle θhx, are set to approximately the same value. The illuminating light beam BSa' , BSb ′ and BSc ′ have isotropic divergence angles θi (= θhy = θhx) around the principal rays parallel to the axis AX2 and perpendicular to the illumination area IAn. Therefore, the numerical aperture NAi of the illumination light beams BSa ′, BSb ′, and BSc ′ irradiated to the illumination area IAn becomes sin (θi). In addition, as shown in FIG. 14 (A) and FIG. 14 (B), if the circular irradiation areas of the illumination light beams BSa, BSb, and BSc irradiated on the incident surface poi of the fly-eye lens system FEn are reduced, the optical axis AX2 starts from Radius, the farthest distances ΔHx, ΔHy from the optical axis AX2 among the numerous spot lights SPa ', SPb', SPc 'formed on the exit surface epi of the fly-eye lens system FEn are also shortened, so the divergence angle θi (= θhy = θhx) also decreases. As a result, the numerical aperture NAi of the illumination beams BSa ′, BSb ′, and BSc ′ decreases, and the illumination σ value also decreases.

[Function of variable magnification section 8A, 8B, 8C]
FIG. 15 (A) and FIG. 15 (B) are the optical fiber bundles 12A (12B, 8B, 8B, 8C) which are irradiated to the incident side by the variable magnification part (numerical aperture variable part) 8A (8B, 8C) shown in FIG. 12C) A diagram illustrating the state where the numerical aperture (divergence angle) of the illumination beam BMa (BMb, BMc) on the incident end FBi is adjusted. In FIG. 15 (A) and FIG. 15 (B), as shown in FIG. 4, the focal position PS2 is a light beam BMa (BMb, BMc) from the mercury lamp 2A (2B, 2C) that passes through the wavelength selection section 6A (6B, 6C). The surface that converges (condenses) with the smallest diameter, at the focal position PS2, forms a circular light source image LDa caused by the blurred image of the arc discharge portion of the mercury lamp 2A (2B, 2C). With the lens system 8A1 (8B1, 8C1) and the lens system 8A2 (8B2, 8C2), the light source image LDa is incident on the incident end FBi of the fiber bundle 12A (12B, 12C) on the incident side, and is then imaged as the light source image LDb.

The lens system 8A1 (8B1, 8C1) is set to a negative power (refractive power), the lens system 8A2 (8B2, 8C2) is set to a positive power (refractive power), and the lens is set as shown in FIG. 15 (A). When the system 8A1 (8B1, 8C1) is separated from the lens system 8A2 (8B2, 8C2), re-imaging is performed as follows: the numerical aperture (divergence angle) NAα of the light beam BMa (BMb, BMc) that forms a light source image It becomes the largest, and the light source image LDb becomes the smallest diameter on the incident end FBi of the fiber bundle 12A (12B, 12C). When the lens system 8A1 (8B1, 8C1) and the lens system 8A2 (8B2, 8C2) are arranged close to each other as shown in FIG. 15 (B), re-imaging is performed as follows: a light beam BMa of a light source image LDb is formed The numerical aperture (divergence angle) NAβ of (BMb, BMc) becomes the smallest, and the light source image LDb becomes the maximum diameter on the incident end FBi of the fiber bundle 12A (12B, 12C). By appropriately adjusting the positions of the respective optical axes AX1 of the two lens systems 8A1 (8B1, 8C1) and 8A2 (8B2, 8C2), the numerical aperture of the light beam BMa (BMb, BMc) forming the light source image LDb ( Divergence angle) is adjusted between the largest NAα to the smallest NAβ. In addition, in the case of FIG. 15 (A), the diameter of the light source image LDb can be set only slightly smaller than the effective diameter of the incident end FBi of the fiber bundle 12A (12B, 12C), as shown in FIG. 15 (B). In this case, the diameter of the light source image LDb can be set only slightly larger than the effective diameter of the incident end FBi of the fiber bundle 12A (12B, 12C).

Within the incident end FBi of the fiber bundle 12A (12B, 12C), in the range where the light source image LDb is formed, that is, the range where the light beam BMa (BMb, BMc) is irradiated, each of the plurality of optical fiber lines is incident from each incident end. The light beam BMa (BMb, BMc) is the light SPa, SPb, SPc from the respective exit ends of the optical fiber lines formed on the exit end FBo of the fiber bundle FGn on the exit side as shown in FIG. 9 or FIG. The illumination beams BSa, BSb, and BSc in a state where the numerical aperture on the incident side (a value ranging from the maximum numerical aperture NAα to the minimum numerical aperture NAβ) is maintained are emitted.

Based on each of the three magnification variable sections 8A, 8B, and 8C shown in FIG. 4, each of the light beams BMa, BMb, and Bmc that will be projected onto the incident end FBi of the fiber bundles 12A, 12B, and 12C on the incident side. When the numerical aperture (divergence angle) is the same, the numerical apertures of the three illumination beams BSa, BSb, and BSc emitted from the emission end FBo of the fiber bundle FGn on the emission side (equivalent to the angle θbo shown in FIG. 11) ) Become the same value. However, if the numerical apertures (divergence angles) of the light beams BMa, BMb, and Bmc on the incident side are different by each of the magnification variable sections 8A, 8B, and 8C, the three illumination beams emitted from the emission end FBo can also be made. The numerical apertures of BSa, BSb, and BSc are different. This will be described with reference to FIG. 16.

FIG. 16 schematically shows the states of the light beams BMa, BMb, and Bmc entering the fiber bundles 12A, 12B, and 12C on the incident side of the fiber bundle shown in FIG. 9 and the fiber bundles FGn (FG1 to FG6) from the exit side. A diagram showing the states of the illuminating light beams BSa, BSb, and BSc emitted in the middle. In FIG. 16, the numerical aperture (wide angle) of the light beam BMa projected on the incident end FBi of the optical fiber bundle 12A is set to NAia, and the numerical aperture (wide angle) of the light beam BMb projected on the incident end FBi of the optical fiber bundle 12B is set to NAib, and the numerical aperture (wide angle) of the light beam BMc projected on the incident end FBi of the fiber bundle 12C is set to NAic, so that the relationship is NAia> NAib> NAic. In this case, the illumination light beam BSa traveling from the divergence of the plurality of spot lights SPa on the exit end FBo of the fiber bundle FG1 formed on the exit side becomes the numerical aperture NAia, and travels from the divergence of the plurality of spot lights SPb. The illuminating light beam BSb becomes a numerical aperture NAib, and the illuminating light beam BSc traveling from each of the plurality of spot lights SPc becomes a numerical aperture NAic. It is the same from the respective emitting ends FBo of the other optical fiber bundles FG2 to FG6, and the illumination light beams BSa, BSb, and BSc with different numerical apertures are emitted simultaneously.

FIG. 17 illustrates the difference in illumination distribution on the incident surface poi of the fly-eye lens system FEn of the illumination light beams BSa, BSb, and Bsc traveling from the exit end FBo of the optical fiber bundle FGn. (Direction) Looking at the schematic diagram of the optical path from the exit end FBo to the incident surface poi of the fly-eye lens system FEn, the orthogonal coordinate system XYZ system is set to be the same as FIG. 11 (B). In FIG. 17, the illumination light beam BSa that travels from the divergence of each of the plurality of spot lights SPa formed on the exit end FBo (equivalent to the pupil plane) of the fiber bundle FGn is converted into a substantially parallel one by the capacitor lens system CPn. The light beam is irradiated by being superimposed on a circular area CFa centered on the optical axis AX1 in the incident surface poi of the fly-eye lens system FEn. Similarly, the illuminating light beam BSb traveling from each of the plurality of point lights SPb is converted into a substantially parallel light beam by the capacitor lens system CPn, and is centered on the optical axis AX1 in the incident surface poi of the fly-eye lens system FEn. The circular area CFb is overlapped and irradiated, and the illumination light beam BSc traveling from each of the plurality of spot lights SPc is converted into a substantially parallel light beam by the capacitor lens system CPn, and is incident on the incident surface poi of the fly-eye lens system FEn. The circular area CFc centered on the optical axis AX1 is irradiated.

Since the exit end FBo of the optical fiber bundle FGn is disposed at the position of the front focal point (pupil plane) of the capacitor lens system CPn, and the incident surface poi of the fly-eye lens system FEn is disposed at the position of the rear focal point of the capacitor lens system CPn. Lighting method, so no matter where each of the plurality of spot lights SPa, SPb, SPc is located on the emission end FBo, the illumination beam BSa from the spot light SPa irradiates the whole within the circular area CFa, from the spot light SPb The illumination light beam BSb irradiates the whole inside the circular area CFb, and the illumination light beam BSc from the spot light SPc irradiates the whole inside the circular area CFc.

FIG. 18 is a diagram showing the states of the circular areas CFa, CFb, and CFc in FIG. 17 distributed on the incident surface poi of the fly-eye lens system FEn in the XY plane. The orthogonal coordinate system XYZ system is set to be the same as that in FIG. 17. . Since the numerical apertures (divergence angles) of the illumination beams BSa, BSb, and BSc are NAia, NAib, and NAic, the relationship is NAia> NAib> NAic. Therefore, as shown in FIG. 18, if the radius of the area CFa centered on the optical axis AX2 is set as Ria, where the radius of the area CFb is set to Rib, and the radius of the area CFc is set to Ric, the relationship is Ria> Rib> Ric. Further, in the area CFc with a radius Ric, the three illumination beams BSa, BSb, and BSc are all superimposed and distributed, and in the ring-shaped region from the radius Ric to the radius Rib in the area CFb, the two illumination beams BSa And BSb are superimposed and distributed, and only the illumination light beam BSa is distributed in the ring-shaped region from the radius Rib to the radius Ria in the area CFa. In addition, the circular area CCA indicated by a dotted line in FIG. 18 indicates a boundary range where the illumination σ value becomes 1.0 (NAi = NAp), and the maximum numerical apertures NAia, NAib, and NAic of the illumination beams BSa, BSb, and BSc are set to Below the numerical aperture corresponding to the radius of the area CCA. Further, corresponding to the maximum radii Ria among the three radii Ria, Rib, and Ric shown in FIG. 18, the positions separated from the optical axis AX2 in the Y direction and the X direction are respectively the same as those in FIG. 14 (A) and FIG. 14 described above. The distances ΔHy and ΔHx described in (B) correspond.

As described above, by adjusting the magnification variable sections (numerical aperture variable sections) 8A, 8B, and 8C shown in FIGS. 4 and 15, the incident surface poi of the fly-eye lens system FEn can be distributed as The radius of each of the circular three illumination beams BSa, BSb, and BSc CFa, CFb, CFc Ria, Rib, Ric can be adjusted freely, so that the numerous spot lights SPa 'formed on the exit surface epi of the fly-eye lens system FEn , SPb ', SPc' have an intensity distribution corresponding to the distance in the radial direction from the optical axis AX2.

19 (A) and 19 (B) show the areas corresponding to CFa, CFb, and CFc of the respective illumination beams BSa, BSb, and BSc shown in FIG. 18, and are formed on the exit surface epi (illumination of the fly-eye lens system FEn). An example of the intensity distribution (light source image) of countless spot lights SPa ', SPb', SPc 'on the pupil surface). FIG. 19 (A) is a view of the fly-eye lens system FEn viewed from the X direction (scanning movement direction), and FIG. 19 (B) is a view of the fly-eye lens system FEn viewed from the Y direction (step moving direction). Countless spot lights SPa 'formed on the exit surface epi of the fly-eye lens system FEn are generated on the incident surface poi on a portion corresponding to the circular area CFa (radius Ria) illuminated by the illumination beam BSa, and are formed on the exit The countless spot lights SPb 'on the surface epi are generated on the part corresponding to the circular area CFb (radius Rib) illuminated by the illumination beam BSb on the incident surface poi, and are formed on the exit surface epi. SPc 'is generated on the incident surface poi at a portion corresponding to the circular area CFc (radius Ric) illuminated by the illumination beam BSc.

When the wavelength characteristics of the three illumination beams BSa, BSb, and BSc are the same, for example, each of the interference filters installed in the wavelength selection sections 6A, 6B, and 6C shown in FIG. 3 and FIG. 4 is set to In the case of the i-ray-narrow-band interference filter SWa shown in FIG. 6, the part corresponding to the exit surface epi (the pupil surface of the illumination system) of the fly-eye lens system FEn corresponding to the circular area CFc with a radius Ric, All three spot lights SPa ′, SPb ′, and SPc ′ having an i-ray (narrow) spectral distribution shown in FIG. 6 are formed to overlap. In addition, two spot lights SPa ', SPb having an i-ray (narrow) spectral distribution are formed on a portion of the exit surface epi (the pupil surface of the lighting system) corresponding to the ring-shaped region from the radius Ric to the radius Rib. 'And only one spot light SPa with a spectral distribution of i-rays (narrow) is formed on the part of the exit surface epi (the pupil plane of the lighting system) corresponding to the ring-shaped region from the radius Rib to the radius Ria' . In addition, a plurality of point lights (point light source images) SPa ', SPb' formed on the exit surface epi (the pupil surface of the illumination system) of the fly-eye lens system FEn shown in Figs. 19 (A) and 19 (B). SPc 'is not evenly distributed in the circular area CCA in FIG. 18 because the reason is that for the purpose of explaining the functions of the variable magnification section (numerical aperture variable section) 8A, 8B, and 8C, they are injected into the optical fiber. The numerical apertures NAia, NAib, and NAic of each of the beams BMa, BMb, and Bmc of the beams 12A, 12B, and 12C are intentionally set to the relationship of NAia> NAib> NAic. In a typical pattern exposure, the numerical apertures NAia, NAib, and NAic of the beams BMa, BMb, and Bmc are set to the relationship of NAia = NAib = NAic.

As shown in FIGS. 19 (A) and 19 (B), a plurality of point lights (point light source images) SPa ', SPb', and SPc 'are distributed on the exit surface epi of the fly-eye lens system FEn (the pupil of the lighting system) When the wavelength characteristics of the light beams BMa, BMb, and Bmc (illumination light beams BSa, BSb, BSc) which are the respective sources of the spot lights SPa ', SPb', and SPc 'are set to the same, irradiate the mask The illuminating light in the illuminating area IAn of the substrate M is shown in FIG. 20 and has a characteristic that the illuminance is different according to the numerical aperture. FIG. 20 schematically shows the alignment characteristics (characteristics of divergence angle) of the illumination beam Irn irradiated to the point OP on the illumination area IAn. Since it is a telecentric illumination condition (Koehler illumination), the illumination beam Irn passing the point OP The main light ray Lpi is perpendicular to the surface of the illumination area IAn (the pattern surface of the mask substrate M). The illumination beam Irn is aligned such that the divergence angle θia from the main ray Lpi corresponding to the numerical aperture NAia becomes the maximum numerical aperture. Within the divergence angle θic of the divergence angle θia corresponding to the numerical aperture NAic, the illuminance of the illumination beam Irn becomes the intensity of adding the three illumination beams BSa, BSb, and BSc, from the divergence angle θib corresponding to the numerical aperture NAib to Between the divergence angle θic, the illuminance of the illumination beam Irn becomes the intensity of adding the two illumination beams BSa, BSb, and between the divergence angle θia to the divergence angle θib, the illumination intensity of the illumination beam Irn becomes only one illumination beam BSa strength. That is, of the overall divergence angle (θia in FIG. 20) of the illumination light beam Irn, the intensity of the divergence angle (θic in FIG. 20) near the center is high, and it can be given a distribution that the intensity decreases as the divergence angle increases.

It is to be noted that each of the illumination areas IAn (IA1 to IA6) on the mask substrate M and each of the projection areas EAn (EA1 to EA6) on the plate P become a conjugate relationship (imaging relationship), so they are projected into the projection area EAn. The exposure imaging beam (diffracted light) at any one of the points has the same alignment characteristics (characteristics of divergence angle) as in FIG. 20.

As described above, by using the variable magnification units (numerical aperture variable units) 8A, 8B, and 8C, the light beams BMa, BMb, and BMc projected onto the incident ends FBi of the fiber bundles 12A, 12B, and 12C on the incident side are used. The numerical aperture (divergence angle) can be adjusted to change the numerical aperture (NAia in FIG. 20) of the entire illumination beam Irn projected in the illumination area IAn on the mask substrate M to change the illumination σ value. It has an illuminance distribution in a range of a divergence angle corresponding to the numerical aperture of the entire illumination beam Irn. Furthermore, by using the variable magnification units (variable numerical aperture units) 8A, 8B, and 8C, the diameters of the beams BMa, BMb, and Bmc can be increased relative to the diameters of the incident ends FBi of the fiber bundles 12A, 12B, and 12C. Or decrease, so can also adjust the respective illuminances (the respective brightnesses of the spot lights SPa, SPb, SPc) of the three illumination beams BSa, BSb, and BSc shown in FIG. 9 or FIG. 16.

[Function of Wavelength Selector 6A, 6B, 6C]
In the sliding mechanism FX of each of the wavelength selection sections 6A, 6B, and 6C shown in FIG. 3 and FIG. 4 described above, for example, 3 having a wavelength selection characteristic as shown in FIGS. 6 to 8 can be installed in an interchangeable manner. One of the interference filters SWa, SWb, and SWc is used for wavelength selection. In this embodiment, it can be adjusted according to the characteristics (characteristics) of the pattern to be exposed on the photomask substrate M due to the combination of the interference filters mounted on the three wavelength selection sections 6A, 6B, and 6C. The wavelength characteristic of the illumination light that irradiates the illumination area IAn of the mask substrate M.

FIG. 21 shows the i-ray-narrow-band interference filter SWa of FIG. 6, the i-ray-broadband interference filter SWb of FIG. 7, and FIG. 8 to be installed at each of the three wavelength selection sections 6A, 6B, and 6C. The combination examples of the i-ray + h-ray-interference filter SWc are summarized in the table. In the table in FIG. 21, the left column is a code that refers to the combination of three types of interference filters SWa, SWb, and SWc. The right three lines of the wavelength spectrum i-ray (narrow), i-ray (wide), i-ray + h-ray The number of ○ marks in the column indicates the number of mercury lamps that generate the wavelength spectrum. In addition, in the following description using FIG. 21, each of the three magnification variable sections 8A, 8B, and 8C is a light beam BMa, BMb, and BM projected by the incident end FBi of the fiber bundles 12A, 12B, and 12C on the incident side. The numerical apertures NAia, NAib, and NAic are set so that they have the same value.

In FIG. 21, the codes A0, A1, A2, A3, A4, and T of the filter combination are installed in any one of the three wavelength selection sections 6A, 6B, and 6C. The i-wave-narrowband interference filter SWa must be installed. In combination, the codes B0, B1, and B2 of the filter combination are installed in any of the three wavelength selection sections 6A, 6B, and 6C without installing the i-ray-narrow-band interference filter SWa, and installing the i-ray- The combination of the wide-band interference filter SWb and the i-ray + h-ray-interference filter SWc. The code C0 of the filter combination is to install i-ray + h-ray-interference in all of the three wavelength selection sections 6A, 6B, and 6C. The combination of the filters SWc. In these combinations, the code A0 has the i-ray-narrow-band interference filter SWa installed in all of the three wavelength selection sections 6A, 6B, and 6C. Therefore, the light amount of the illumination beam Irn in the illumination area IAn on the mask substrate M is the same. It is obtained by multiplying the light quantity of the i-ray (narrow) spectral distribution (refer to FIG. 6) from each of the three mercury lamps 2A, 2B, and 2C by about three times, and it can be obtained at a relatively high illuminance. High-resolution pattern exposure. In addition, code A1 is to install an i-ray-narrowband interference filter SWa in two of the three wavelength selection sections 6A, 6B, and 6C, and to install an i-ray-broadband interference filter in the remaining one. In the case of SWb, the amount of light from the illumination beam Irn in the illumination area IAn on the mask substrate M is the spectral distribution of the i-rays (narrow) from two of the three mercury lamps 2A, 2B, and 2C (see FIG. 6). Approximately twice the amount of light is obtained by adding the amount of light from the i-ray (wide) spectral distribution (see Figure 7) from one of the three mercury lamps 2A, 2B, and 2C, compared with the combination of code A0 While maintaining the performance of high-resolution pattern exposure, the amount of light from the illumination beam Irn only increased by a few percent.

In FIG. 21, the combination code T means that the interference filters SWa, SWb, and SWc are installed differently in each of the three wavelength selection sections 6A, 6B, and 6C, and the combination code B0 means the three wavelength selection sections 6A, 6B. Only i-broadband interference filter SWb is installed in all of 6C, and the combination code C0 means that only i-ray + h-ray-interference filter SWc is installed in all of the three wavelength selection sections 6A, 6B, and 6C. . As clearly shown in the table of FIG. 21, no matter which combination code is used, the illumination beam Irn irradiated in the illumination area IAn contains approximately 100% of the i-rays from each of the three mercury lamps 2A, 2B, and 2C. The bright line component. However, according to the combination of the interference filters SWa, SWb, and SWc, for example, the intensity ratio of the bright line component of the i-ray and the bright line component of the h-ray can be set to be different from the original intensity ratio of the mercury lamp (see FIG. 5). Its spectral distribution.

FIG. 22 is a graph schematically showing a wavelength characteristic of the illumination light beam Irn obtained according to the combination code B2 in the table of FIG. 21. In combination code B2, an i-ray-broadband interference filter SWb is installed in one of the three wavelength selection sections 6A, 6B, and 6C, and an i-ray + h-ray is installed in each of the other two wavelength selection sections. -Interference filter SWc. In this case, the light quantity obtained by multiplying the spectral distribution of the i-ray + h-ray shown in FIG. 8 by 2 times and adding the light quantity of the spectral distribution of the i-ray (wide) shown in FIG. 7 becomes illumination. Wavelength spectrum distribution of the light beam Irn. Therefore, in the case of combining code B2, the light amount of the bright line component of the i-ray becomes 3 times that of a mercury lamp, and the light amount of the bright line component of the h-ray becomes 2 times that of one mercury light. The illumination beam Irn can be changed. The light amount of the bright line component of the i-ray and the bright line component of the h-ray in the wavelength spectrum distribution is balanced, that is, the spectral characteristics of the illumination beam Irn can be changed according to the tendency of the spectral characteristics of the light from the mercury lamp (see FIG. 5).

Regarding the above embodiment, it can be supplemented as an exposure method in which light including bright-line wavelengths (for example, i-rays, h-rays, and g-rays) generated by a light source device (mercury discharge lamps 2A, 2B, 2C) is used. The light including the spectral distribution of a specific bright line wavelength selected by the wavelength selection section (6A, 6B, 6C) uses an illumination optical system (Fig. 3) to illuminate the illuminated area on the mask substrate M carrying the pattern for electronic components. IAn (IA1 to IA6) is irradiated, and a projection optical system (partial projection optical systems PL1 to PL6) that emits an exposure light beam (imaging light beam) generated by the mask substrate M (illumination area IAn) is used to form a patterned image When projection exposure is performed on a light-sensitive substrate (plate P), as shown in the combination codes A1 to A4, T, and B0 to B2 of FIG. 21, the wavelength band is extracted from the light generated by the light source device through the wavelength selection section. Light with different first spectral distribution (for example, spectral component selected by i-ray-narrow-band interference filter SWa) and light with second spectral distribution (for example, selected by i-ray + h-ray-interference filter SWc) Spectral component) At least two, in order to use the illumination optical system to illuminate the mask substrate M, the pupil surface (the exit surface epi of the fly-eye lens system FEn) on the pupil surface in the illumination optical system will have light due to the first spectral distribution. The first light source image distributed in the two-dimensional range (for example, a collection of most point light source images SPa 'in FIG. 13), and the second light source image distributed in the two-dimensional range due to the light of the second spectral distribution (for example, FIG. The plurality of point light sources like SPb ′ in 13 are formed overlappingly, whereby, as illustrated in FIG. 20, the angular range corresponding to the maximum numerical aperture of the illumination beam Irn irradiated onto the mask substrate M (FIG. Within the incident angle θia in 20), the balance of wavelength and intensity (wavelength intensity characteristic) is different depending on the angle.

[Cooperation between wavelength selection section and variable magnification section]
In the above description, the numerical apertures NAia, NAib, of the light beams BMa, BMb, and Bmc set by each of the variable magnification units 8A, 8B, and 8C and projected onto the respective incident ends FBi of the fiber bundles 12A, 12B, and 12C are NAia, NAib, NAic is set to the same value, but the numerical apertures NAia, NAib, and NAic of the beams BMa, BMb, and Bmc can be set to different values while the interference filters installed in the wavelength selection sections 6A, 6B, and 6C can be set. Differently, as shown in FIG. 20 described above, a difference in illuminance can be given according to a divergence angle (θia, θib, θic) of the illumination light beam Irn, and a difference in wavelength characteristics can be given. For example, the numerical apertures NAia, NAib, and NAic shown in FIG. 20 are set to the relationship of NAia = NAib> NAic (the radius Rib shown in FIG. 18 and FIG. 19 is set to a relationship equal to the radius Ria), as shown in FIG. 21 Like the combination code A2, an i-ray-narrow-band interference filter SWa is installed in each of the wavelength selection sections 6A and 6B, and an i-ray + h-ray-interference filter SWc is installed in the wavelength selection section 6C. In this case, on the exit surface epi of the fly-eye lens system FEn shown in FIG. 19, there is an i-ray (narrow) spectral distribution throughout the entire area of the circular area CFa with a radius of Ria (= Rib) (FIG. 6 ) Countless spot lights SPa 'and SPb' are also arranged in the circular area CFc with a radius of Ric, and furthermore, countless spot lights SPc 'with a spectral distribution of i-rays + h-rays (Figure 8) are also arranged in the same way .

Therefore, according to this embodiment, it is possible to make a secondary light source image (an infinite number of point lights SPa ', SPb', The wavelength characteristics within the distribution range of the SPc 'aggregate image) vary depending on the position in the diameter direction from the optical axis AX2. In this case, the rays within the range (numerical aperture NAic) of the divergence angle θic from the main ray Lpi of the illumination beam Irn that illuminates the mask substrate M shown in FIG. 20 include i rays and The spectrum of the two bright-line wavelengths of the h-rays includes only the i-rays (width) in the light in a ring-shaped range (numerical aperture NAic to NAia) between the divergence angle θic to the divergence angle θia (= θib). Of the spectrum. As described above, if the wavelength characteristics of the secondary light source image formed on the illumination pupil surface of the second illumination optical system ILn are changed in the diameter direction, the pattern formed on the mask substrate M can be suppressed from the halftone pattern. The quality of the projected image is reduced due to the effects of pattern manufacturing errors, etc. in the case of phase shift patterns.

Generally, a halftone pattern or a phase shift pattern is premised on the use under illumination of a specific wavelength of illumination, and the displacement of the management film thickness is formed on the mask substrate so that the amplitude transmittance at that specific wavelength becomes a predetermined condition. Layer. However, in the case where an error occurs in the film thickness or when the numerical aperture (illumination σ value) of the illumination light is changed, the amplitude transmittance of the displacement layer changes (deteriorates) from the required condition. The contrast of the pattern image of the projection exposure and the degradation of the imaging performance in which the target fineness cannot be obtained. In the present embodiment, even in the case of using a photomask substrate having the halftone pattern or the phase shift pattern as described above, it is possible to form a two-dimensionally formed illumination optical system for illuminating the photomask substrate M (second Illumination optical system ILn) The wavelength characteristics (spectrum) of the light source image on the illumination pupil surface are different in the diameter direction, so if there is an error in the film thickness of the displacement layer, or the numerical aperture of the illumination light (illumination σ value) is changed In this case, it is also possible to suppress a decrease in imaging performance caused by a change (deterioration) in the amplitude transmittance of the displacement layer.

[Modification 1]
As described above, in the first embodiment, three mercury lamps 2A, 2B, and 2C are set as ultra-high-pressure mercury discharge lamps of the same specifications. The bright-line wavelengths of i-rays and bright-line wavelengths of h-rays are mainly used for pattern exposure. The bright-line wavelength of g-rays can also be used for pattern exposure. In this case, a projection optical system that is corrected for chromatic aberration in a wide wavelength range including three bright lines of i-ray, h-ray, and g-ray is used. In addition, as disclosed in Japanese Patent Application Laid-Open No. 2012-049332, a projection exposure apparatus equipped with a projection optical system having a specular projection method in which a large concave mirror and a small convex mirror are combined can also be applied with the illumination device of this embodiment (No. 1 illumination optical system, 2nd illumination optical system ILn). Since the projection optical system of the specular projection method does not use a lens element with strong refractive power, it basically does not produce chromatic aberration caused by the difference in the wavelength of the illumination light. It can easily use three types of i-rays, h-rays, and g-rays of mercury lamps. Bright line wavelength. In addition, although the three mercury lamps 2A, 2B, and 2C are ultrahigh-pressure mercury discharge lamps of the same specifications, as for the wavelength characteristics of the light from the arc discharge section, i-rays, h-rays, and g-rays can also be A combination of a high-pressure mercury discharge lamp having a ratio of peak intensity and a ratio different from that shown in FIG. 5 and an ultra-high-pressure mercury discharge lamp may be combined with a short-arc type low-pressure mercury discharge lamp and an ultra-high-pressure mercury discharge lamp, as appropriate. The number of the first illumination optical system from the mercury lamp 2 to the incident optical fiber bundle 12 may be 2 or more. For example, when the number of partial projection optical systems PLn is 6 or more, in order to ensure the illuminance of the illumination beam Irn As long as four mercury lamps 2A to 2D, four first illumination optical systems, and four incident side optical fiber bundles 12A to 12D can be provided.

[Modification 2]
The interference filters installed in the wavelength selection sections 6A, 6B, and 6C shown in FIGS. 3 and 4 are i-ray-narrow-band interference filters having wavelength characteristics shown in FIGS. 6 to 8 respectively. SWa, i-ray-broadband interference filter SWb, i-ray + h-ray-interference filter SWc, but when the projection optical system (partial projection optical system PLn) can be used to the wavelength of g-ray, A g-ray-narrow-band interference filter or a g-ray-broadband interference filter, an i-ray + h-ray + g-ray-interference filter for ultra-wideband can be prepared and mounted on the sliding mechanism FX. In addition, in order to include only the bright-line wavelength of the h-ray, an h-ray-narrow-band interference filter or an h-ray-broadband interference filter may be prepared. When preparing an interference filter including only the bright-line wavelength of the h-ray, for example, one of the i-ray-narrow-band interference filter SWa or the i-ray-broadband interference filter SWb is installed in the wavelength selection Each of the sections 6A, 6B, and one of the h-ray-narrowband interference filter or the h-ray-broadband interference filter is mounted on the wavelength selection section 6C. In addition, each of the magnification variable sections 8A, 8B, and 8C is adjusted so that the numerical aperture NAia of the light beam BMa (i-ray) incident on the optical fiber bundle 12A and the light beam BMb (i-ray) incident on the optical fiber bundle 12B are adjusted. The numerical aperture NAib is set to the same value such that the illumination σ value becomes a large value (for example, 0.7 or more). The numerical aperture NAic of the light beam Bmc (h-ray) incident on the fiber bundle 12C is NAia = NAib ＞ NAic Relationship mode setting.

In this case, a secondary light source image (a collective image of countless point lights SPa ', SPb', SPc 'formed on the exit surface epi of the fly-eye lens system FEn, which becomes the illumination pupil surface of the second illumination optical system ILn. ), Including: Countless spot light SPa including only the bright-line wavelength of i-rays scattered in the whole in the area CFa (= CFb) with a radius Ria (= Rib) corresponding to the numerical aperture NAia (= NAib) ', SPb'; and an unlimited number of point lights SPc 'including only bright-line wavelengths of h-rays scattered only in the area CFc with a radius Ric corresponding to the numerical aperture NAic. Therefore, the secondary light source image formed on the exit surface epi of the fly-eye lens system FEn is set to have a wavelength distribution characteristic that is approximately constant over the entire CFa (corresponding to the largest numerical aperture NAia) across the area with a radius of Ria. The intensity component of the bright-line wavelength spectrum of the i-ray includes a spectral component of the bright-line wavelength of the h-ray only distributed in the area CFc with a radius Ric (<Ria) inside.

In addition, when preparing an h-ray-narrow-band interference filter or an h-ray-broadband interference filter, they can also be formed in the second illumination by adjusting each of the variable magnification units 8A, 8B, and 8C. The wavelength distribution characteristics of the secondary light source image on the illumination pupil plane of the optical system ILn are set to be opposite to the above. That is, the entirety of the area CFa (corresponding to the largest numerical aperture NAia) of the secondary light source image having a radius of Ria formed on the illumination pupil surface (emission surface epi) of the second illumination optical system ILn may be used as the h-ray. The spectral component of the bright-line wavelength of the bright line, and only the spectral component of the bright-line wavelength of the i-ray in the area CFc with a radius Ric (<Ria) on the inner side. In addition, the interference filter is a band-pass filter that extracts a spectral component of a predetermined wavelength width, and a low-pass filter that transmits a wavelength component that is longer than the cut-off wavelength and a transmission that is shorter than the cut-off wavelength. The high-pass filters with wavelength components are arranged in series, and are mounted between the lens systems 6A1 and 6A2. In this case, prepare a low-pass filter with a cut-off wavelength set around 350 nm to 360 nm, a first high-pass filter with a cut-off wavelength of about 375 nm, and a second high-pass filter with a cut-off wavelength of about 395 nm. The filter is provided with a first high-pass filter and a second high-pass filter in an interchangeable manner. Thus, in the combination of the low-pass filter and the first high-pass filter, the i-ray (narrow) spectral component shown in FIG. 6 is extracted, and the combination of the low-pass filter and the second high-pass filter is used. In FIG. 7, the spectral components of the i-ray (wide) are extracted as shown in FIG. 7.

[Modification 3]
At the manufacturing stage of the substrate of the display panel or the circuit board for mounting electronic parts, or a fine metal mask (a so-called stencil mask) installed in the evaporation device to divide the evaporated portion on the substrate to be processed. In the manufacturing stage and the like, pattern exposure may be performed on a negative photoresist layer (photosensitive layer) coated on the plate P with a thickness of several times to 10 times the normal thickness (0.5 to 1.5 μm). Negative photoresist has more sensitivity than positive photoresist, and the part irradiated by the exposure illumination beam Irn has the characteristics of insolubility to the developing solution and residual film. Furthermore, the negative photoresist may have a large difference in sensitivity or absorptivity to the wavelength of the exposure illumination beam Irn. FIG. 23 is a graph showing an example of the light absorption characteristics of a negative photoresist showing the wavelength (nm) of the illumination light beam Irn on the horizontal axis and the standardized absorptivity (0 to 1) on the vertical axis. In the case of the photoresist of Fig. 23, there is an absorption peak near the wavelength of 320 nm, and the characteristic is that the absorptivity decreases linearly between the wavelengths of 320 and 450 nm (wavelength dependence of the absorptivity), i The absorptivity of the bright-line wavelength of 365 nm of the ray becomes approximately 0.5, and the absorptivity of the bright-line wavelength of 405 nm of the h-ray becomes approximately 0.15. The characteristic of FIG. 23 is an example, and it varies greatly depending on the material of the resist. When the thickness of the negative photoresist layer having the characteristics as shown in FIG. 23 is 10 μm or more, the pattern is performed by using an illumination beam Irn including both the bright-line wavelength of the i-ray and the bright-line wavelength of the h-ray. According to the wavelength dependence of the absorptance, a large amount of light of the bright-line wavelength of the i-ray is absorbed on the surface portion of the resist layer during exposure, and a sufficient amount of light is not given to the bottom side (plate P side) of the resist layer. On the other hand, since the light of the bright-line wavelength of the h-ray has less absorption in the resist layer, a sufficient amount of light is also given to the bottom side (plate P side) of the resist layer.

Because the thickness of the resist layer is large and the wavelength dependence of the absorptivity is present, if each of the wavelength selection sections 6A, 6B, and 6C is mounted with the i-ray + h-ray-interference filter SWc shown in FIG. 8 (selection diagram) The combination code C0 in the table of 21), when the pattern of the photomask substrate M is projected and exposed on the plate P, the edge portion (side wall) of the pattern (resist image) of the resist layer of the residual film after development can be projected. It is in a state of being inclined not perpendicular to the surface of the plate P. FIG. 24 is a cross-sectional view schematically showing an inclination of an edge portion (side wall) of a resist image of a residual film after development. In FIG. 24, on the surface of the plate P (here, a metal film such as nickel is formed on the surface), a negative resist layer Luv is formed with a thickness RT (10 μm or more). After the development, the resist layer Luv is formed. The unexposed portion (non-irradiated portion) is removed, and an opening portion HL is formed between the edge portions Ewa and Ewb. In the case of manufacturing a fine metal mask, a metal layer (such as nickel or copper) is deposited on the plate P exposed in the opening HL by electroplating. The sidewalls of the edge portions Ewa and Ewb serving as the resist layer Luv are formed here so as to be inclined toward the opening HL side, which is a so-called inverted cone shape.

As described above, in order to control the amount of inclination of the sidewalls of the edge portions Ewa, Ewb, which become the resist image, to a desired value, the interference filter mounted on each of the wavelength selection portions 6A, 6B, and 6C can be used. Combination to adjust the light amount of the bright-line wavelength of the i-ray included in the illumination beam Irn (equivalent to the area of the oblique line in FIG. 6 or 7) and the light amount of the bright-line wavelength of the h-ray; or by Each of the magnification variable sections 8A, 8B, and 8C independently adjusts the numerical aperture of the illumination beam of the bright-line wavelength of the i-ray included in the illumination beam Irn, and the numerical aperture of the illumination beam of the bright-line wavelength of the h-ray, etc. . In addition, it is not limited to a negative type photoresist to give a desired tilt amount to the side walls of the edge portions Ewa and Ewb which become a developed resist image, and it can be performed similarly to a positive type photoresist.

In the case where the resist layer Luv is used as a masking layer in the plating step during the manufacture of a fine metal photomask or the formation of a wiring layer, Tokyo Yinghua Chemical Industry Co., Ltd. may be used as a photoresist for plating. The products to be sold are PMER P-CS series, PMER P-LA series, PMER P-HA series, PMER P-CE series, or naphthoquinone or chemically amplified PMER P-WE series, PMER P-CY series. Resist, negative photoresist under the trade name PMER-N-HC600PY, etc. In addition, plating resists sold under the trade names of SPR-558C-1 and SPR-530CMT-A sold by Shanrong Chemical Co., Ltd. can also be used. In addition, it is also possible to use a UV-curable monomer / oligomer (epoxy acrylate, acrylate urethane, polyester acrylic acid) having an appropriate light absorption in the wavelength region of the illumination beam Irn at the time of pattern exposure. Ester), a photopolymerization initiator, a photosensitizer, an additive, and the like as a UV-curable resin having a composition are set as a photosensitive layer as a resist layer Luv.

[Modification 4]
Pattern exposure can be performed when only an i-ray-narrow-band interference filter or an i-ray-broadband interference filter is used, and the exposure illumination beam Irn is set to include only light of the bright-line wavelength of the i-ray. At the time of high resolution, the depth of focus (DOF: Depth of Focus) also decreases with the high resolution (shorter wavelength of the illumination beam). Therefore, in order to suppress the reduction of DOF in a high-resolution state, there is also a case where the shape of a light source image (secondary light source image) formed on the illumination pupil surface of the illumination optical system is set to be a ring shape, and is set to be illuminated. In the pupil plane, the position (area) with a point symmetrical about the optical axis as the center is biased to a quadrupole shape. In this case, an aperture plate (illumination aperture diaphragm) having an endless belt-shaped or 4-pole light-transmitting portion is provided at or near the exit surface epi of the fly-eye lens system FEn.

FIGS. 25 (A) and 25 (B) are diagrams showing the shapes in the XY plane of the diaphragm plate APa having the annular light-transmitting portion and the diaphragm plate APb having the quadrupole-shaped light transmitting portion, respectively. In the figure, the orthogonal coordinate system XYZ system is consistent with the above-mentioned FIG. 18. The aperture plate APa removes a light-shielding layer such as chromium vapor-deposited on the surface of a parallel flat plate of quartz into an endless belt shape by etching. As shown in FIG. 25 (A), an endless belt-shaped light transmitting portion TPa is formed. In the same way, the diaphragm plate APb removes the light-shielding layer on the surface of the parallel flat plate of quartz into a 4-pole shape by etching. As shown in FIG. 25 (B), four of the XY coordinates with the optical axis AX2 as the origin Each of the quadrants is formed with a fan-shaped light transmitting portion TPb. In addition, the diaphragm plate APb may be a light-shielding portion in which the light-shielding belts extending in the X and Y directions intersect in a cross shape at the position of the optical axis AX2.

[Modification 5]
On the wavelength selection section 6A (6B, 6C) included in the first illumination optical system shown in FIG. 4 above, a lens system (collimating lens) 6A1 is provided, which will be from the elliptical mirror 4A (4B, 4C) The second focal point position PS1 diverges and travels a light beam BM that is incident to be converted into a substantially parallel light beam; and a lens system 6A2 that converges the substantially parallel light beam on the focal position PS2. In the optical path between the lens systems 6A1 and 6A2, any one of the interference filters SWa, SWb, SWc, etc. is installed, but a ring-shaped diaphragm plate as shown in FIG. 25 (A) can also be combined. FIG. 26 is a diagram showing a state in which a ring-shaped diaphragm plate APa ′ is arranged on the wavelength selection section 6A of the first illumination optical system, and the same components as those shown in FIG. 4 are denoted by the same reference numerals.

In Fig. 26, the ring-shaped diaphragm plate APa 'is formed by forming the following layers on a flat plate of quartz: a light-shielding layer near the bottom, which has a maximum diameter equal to that of a light beam BM which becomes a substantially parallel light beam by the lens system 6A1. Correspondingly, the outer side diameter of the outer wheel diameter is shielded; and a circular central light-shielding layer that shields the inner side of the inner wheel diameter centered on the optical axis AX1. The diaphragm plate APa ′ is mounted on the sliding mechanism FX similarly to the interference filter SWa (or SWb, SWc, etc.), and is provided so as to be insertable and removable in the optical path. The illuminating light beam BMa transmitted from the ring-shaped light transmitting portion TPa of the ring-shaped diaphragm plate APa ′ converges on the focal position PS2 by the lens system 6A2, and then diverges again toward the variable magnification portion 8A at the rear stage. The outer diameter of the diaphragm APa 'specifies the maximum numerical aperture NAd1 of the illumination beam BMa. The inner diameter of the diaphragm APa' specifies the diameter of the illumination beam BMa in the cross section of the illumination beam BMa. Numerical aperture NAd2.

The illumination beam BMa having an intensity distribution in the shape of an annular band by the diaphragm APa ′ is adjusted by the numerical magnification section 8A at the rear stage to adjust the overall numerical aperture when it is incident on the incident end FBi of the fiber bundle 12A. The light beam incident on each optical fiber line of the incident end FBi of the optical fiber bundle 12A becomes a ratio that maintains the maximum numerical aperture NAd1 and the numerical aperture NAd2 in the hollow range. As explained in FIG. 16 above, each optical fiber line transmits light while keeping the numerical aperture (divergence angle) of the incident light. Therefore, the numerical values of the light beams BSa emitted from the respective exit ends FBo of the optical fiber bundles FGn on the exit side. The aperture becomes the same as the numerical aperture of the light beam BMa incident from the incident end FBi of the optical fiber bundle 12A. Therefore, in the case of this modification, the light beam BSa (the divergent light beam from the point light SPa formed on the output end FBo) emitted from the respective output ends FBo of the optical fiber bundle FGn has a maximum numerical aperture NAd1 and An annular band distribution of the ratio of the numerical aperture NAd2 in the hollow range. The illumination light beam BSa traveling from each of the plurality of spot lights SPa formed on the respective exit ends FBo of the optical fiber bundle FGn is traveling on the incident surface poi of the fly-eye lens system FEn as explained in FIG. 17 above. The illumination beam BSa itself has a ring-shaped intensity distribution, so it is a ring-shaped band on the incident surface poi of the fly-eye lens system FEn to maintain the ratio (ring-band ratio) of the maximum numerical aperture NAd1 to the numerical aperture NAd2 of the hollow range. The distributions overlap. Similarly, in the optical paths of the other wavelength selection sections 6B and 6C, a ring-shaped diaphragm plate APa ′ is also detachably provided.

As described above, in this modification, at least one of the illumination light beams BSa, BSb, and BSc that can be irradiated on the incident surface poi of the fly-eye lens system FEn is set to have a center around the optical axis AX2. The ring-shaped band strength distribution is required. Therefore, by adjusting the variable magnification units 8A, 8B, and 8C, countless spot lights SPa ', SPb', and SPc 'formed on the exit surface epi of the fly-eye lens system FEn, such as the spot lights SPa' and SPb ' It can be distributed in a ring-shaped range outside the area CFc having a radius Ric as shown in FIG. 18 or 19, and the spot light SPc 'can be distributed within the area CFc having a radius Ric as shown in FIG. 18 or 19. At this time, by appropriately selecting a combination of interference filters installed in each of the wavelength selection sections 6A, 6B, and 6C, for example, it is possible to distribute spot light in a ring-shaped range outside the area CFc with a radius of Ric. SPa 'and SPb' have an i-ray (narrow) spectrum, and the point light SPc 'distributed in the area CFc with a radius Ric can have an h-ray (narrow) spectrum. That is, the wavelength characteristics of the light source image formed on the illumination pupil surface (the exit surface epi of the fly-eye lens system FEn) of the second illumination optical system ILn can be determined based on the distance from the optical axis AX2 (corresponding to the numerical aperture). Change to a completely different wavelength.

In addition, as shown in FIG. 26, the ring-shaped diaphragm plate APa 'is provided in the optical path in the wavelength selection section 6A (6B, 6C), but may be provided in the optical path in the variable magnification section 8A (8B, 8C). in. Further, a diaphragm plate APb ′ similar to the quadrupole diaphragm plate APb shown in FIG. 25 (B) may be installed instead of the annular band diaphragm plate APa ′ in FIG. 26. In this case, the illumination light beam BSa (or BSb, BSc) irradiated on the incident surface poi of the fly-eye lens system FEn overlaps the four fan-shaped areas like the light transmitting portion TPb of FIG. 25 (B). In addition, in this modification, the illumination beam BSa (or BSb, BSc) irradiated on the incident surface poi of the fly-eye lens system FEn and the ordinary circular shape including the optical axis AX2, the endless belt shape not including the optical axis AX2, Or the quadrupole region overlaps, so if the secondary light source images (point lights SPa ', SPb', SPb ', SPb', SPb ', SPb', SPb ', SPc ') also has the advantage of suppressing the loss of the amount of illumination light to a small amount compared to the case of a part.

[Second Embodiment]
FIG. 27 is a diagram showing a schematic overall configuration of an exposure apparatus according to a second embodiment, and the Z axis of the orthogonal coordinate system XYZ is set to the direction of gravity. The detailed configuration of the exposure device as shown in FIG. 27 is disclosed in, for example, International Publication No. 2013/094286 and International Publication No. 2014/073535. Therefore, the following description of the device configuration is briefly performed. The exposure device shown in FIG. 27 is designed to scan a pattern of an exposure mask on a flexible long sheet-like substrate FS, and bends a cylindrical surface with a certain radius from a center line CC1 set parallel to the Y axis, and A reflective pattern is formed on the outer peripheral surface having a predetermined length in the Y direction (a length corresponding to the width in the Y direction of the sheet substrate FS), and a cylindrical photomask DMM that rotates about the centerline CC1 is installed. Further, the exposure apparatus of FIG. 27 is provided with an outer peripheral surface having a cylindrical surface curved at a certain radius from a center line CC2 parallel to the Y axis, and is closely adhered to the outer peripheral surface in a long direction. A drum DR supporting a sheet-like substrate FS and rotating around a centerline CC2. Between the cylindrical reticle DMM and the rotating drum DR spaced in the Z direction, a partial projection optical system PL1 (and not shown) having an odd-numbered equal-magnification imaging having a structure substantially the same as the structure shown in FIG. 2 described above is provided. The part of the projection optical systems PL3, PL5, etc. shown), and the part of the projection optical system PL2 (and the part of the projection optical systems PL4, PL6, etc., not shown) with equal magnification.

A polarizing beam splitter PBSa for epi-illumination is provided between the outer peripheral surface of the cylindrical mask DMM and each of the odd-numbered partial projection optical systems PL1, PL3, PL5, .... A 1/4 wavelength plate (or film) is mounted on the surface of the cylindrical mask DMM side of each polarizing beam splitter PBSa. On the outer peripheral surface of the cylindrical mask DMM, each of the elongated rectangular illumination areas IAn in the Y direction is set, and the second illumination optics having an odd number and having a configuration substantially the same as that of the second illumination optical system ILn shown in FIG. 10 described above. The illumination light beams for exposure from each of the systems IL1, IL3, IL5 ... and the even-numbered second illumination optical systems IL2, IL4, IL6 ... are projected through the polarizing beam splitters PBSa, PBSb. The polarizing beam splitters PBSa, PBSb (and 1/4 wavelength plate) separate the illumination beam toward the illumination area IAn of the cylindrical mask DMM from the reflected beam from the mask pattern appearing in the illumination area IAn according to the polarization state, but For this reason, it is necessary to make the illumination light beams projected on the polarization beam splitters PBSa and PBSb linearly polarized in advance. Therefore, an appropriate position in the illumination light path of the second illumination optical system ILn is, for example, a position from the fiber bundle FGn on the emission side shown in FIG. 10 to the second capacitor lens system CPn, or the first capacitor lens system CPn shown in FIG. 4. A polarizing plate is provided in the wavelength selection section 6A, 6B, 6C of the illumination optical system, or in front of or behind the variable magnification section 8A, 8B, 8C.

If the plane including the centerline CC1 of the cylindrical mask DMM and the centerline CC2 of the drum DR and parallel to the YZ plane is set as the central plane CCp, when viewed in the XZ plane (inside the paper plane of FIG. 27), The odd numbered projection optical systems PL1, PL3, PL5 ... and the odd numbered second illumination optical systems IL1, IL3, IL5 ..., and the even numbered projection optical systems PL2, PL4, PL6 ... and The even-numbered sets of the second illumination optical systems IL2, IL4, IL6,... Are arranged symmetrically with respect to the center plane CCp. In addition, the main light rays on the respective cylindrical mask DMM sides of the partial projection optical system PLn where the reflected light beams of the patterns generated by each of the illumination areas IAn on the cylindrical mask DMM are incident are directed toward the center with their extension lines. The line CC1 is set; on the respective DR side of the partial projection optical system PLn, the main light rays of the imaging beams projected on the projection area EAn set on the sheet substrate FS are directed toward the centerline with their extension lines. CC2 mode setting.

In this embodiment, since the projection magnification of the partial projection optical system PLn is equal (1: 1), the radius from the centerline CC1 of the outer peripheral surface (pattern forming surface) of the cylindrical mask DMM and the rotating drum The radius of the outer peripheral surface of DR from the center line CC2 (strictly speaking, the radius plus the thickness of the sheet substrate FS) is set to be equal, so that the cylindrical mask DMM and the drum DR are rotated at the same rotation speed, so that The reflected light beam from the pattern for the elements formed by the high reflection portion and the low reflection portion on the cylindrical mask DMM is scanned and exposed on the sheet substrate FS. At this time, a film body formed of a single layer or a plurality of layers is formed on the pattern forming surface of the cylindrical photomask DMM, and the high reflection part has as high a reflection as possible for the illumination light beam from the second illumination optical system ILn. And the low-reflection portion has as low a reflectance as possible (ideally, the reflectance is zero). As an example of a method for producing a reflective mask pattern, there is a method in which a wavelength spectrum of an exposure illumination light beam becomes a first film body (metal having a high reflectance (for example, 80% or more, preferably 90% or less)). Thin film, etc.), after vapor deposition on the entire surface of the pattern forming surface of the cylindrical mask DMM, the wavelength spectrum of the exposure illumination beam becomes a low reflectance (for example, 10% or more, preferably 5% or less). 2 The film body (metal thin film or dielectric multilayer film, etc.) is laminated on the surface of the first film body, and patterning using a photolithography method, etc., and a part of the second film body that becomes a low reflection portion remains as A part of the high reflection part is removed by etching, and the first film body of the base is exposed. In addition, contrary to this method, a method may also be adopted in which a second film having a low reflectance is first deposited on the entire surface of the pattern forming surface of the cylindrical mask DMM, and then onto the surface of the second film The upper layer becomes the first film body with high reflectivity, and the portion of the first film body that becomes the high reflection portion is retained, and the portion serving as the low reflection portion is removed by etching to expose the second film body of the base.

Also, in the same manner as the halftone method or the phase shift method used in the transmissive photomask substrate, in the case of a reflective pattern, a reflective displacement pattern can also be used, and the reflection on the pattern forming surface is laminated. The surface of the film forms a fine step difference corresponding to the wavelength of the illumination beam, and is set to a phase difference in which the amplitude and intensity of the reflected light generated on the upper and lower surfaces of the step cancel each other out. In this case, a film body having a high reflectance is formed uniformly on the entire surface of the pattern forming surface of the cylindrical mask DMM, and a pattern portion on the surface of the film body that reduces the reflected light is formed to give the reflected light. Diffraction grating-shaped or checker-shaped concave-convex pattern composed of a small step difference of 180 degrees with a phase difference (so that the amplitude reflectance is zero). In the case of a step structure having a phase difference other than 180 degrees to the reflected light, since the amplitude reflectance becomes a finite value other than zero, an intermediate reflectance can also be obtained.

In the exposure apparatus using the reflective mask as described above, there is a case where the reflectance of the reflective pattern is uneven due to the exchange of the mask (cylindrical mask DMM). Especially in the reflective displacement pattern, due to the manufacturing error of the minute steps formed on the surface of the film, the phenomenon that the reflectance of the pattern portion where the intensity of the reflected light is substantially zero is not sufficiently reduced is caused. Moreover, even in the case of a reflective pattern composed of only a high-reflection part and a low-reflection part, if the pattern is formed on the outer peripheral surface of the cylindrical mask DMM as shown in FIG. 27, the pattern is curved toward the circumferential direction of the cylindrical mask DMM. Therefore, according to the position in the circumferential direction in the illumination area IAn, the incident angle of the main ray of the illumination beam slightly changes, and there may be a difference in the reflectance in the illumination area IAn.

Therefore, in this embodiment, as described in the above-mentioned first embodiment or its modification, the combination of the interference filters mounted on the wavelength selection sections 6A, 6B, and 6C is changed, or the magnification is variable. Each of the sections 8A, 8B, and 8C is adjusted to change the diameters (numerical apertures) of the illumination light beams BSa, BSb, and BSc projected on the incident surface poi of the fly-eye lens system FEn, or to make the incident on the fly-eye lens system FEn The respective areas (shapes) of the illumination beams BSa, BSb, and BSc on the surface poi can be reduced, thereby reducing unevenness in reflectance caused by manufacturing errors of the reflective pattern or possible occurrence of curved pattern surfaces. Uneven reflectance. Especially as illustrated in FIG. 20 or FIG. 26, the intensity distribution or numerical aperture of each wavelength can be adjusted within the range of the maximum divergence angle (maximum numerical aperture) of the illumination beam Irn projected in the illumination area IAn, so even if It also has the advantage that it can be easily corrected when a change or unevenness in the reflectance occurs in the reflective mask pattern.

[i-ray-broadband interference filter]
As shown in FIG. 6 above, the normal i-ray interference filter SWa is set to center on the bright-line wavelength of the i-ray, and extract (transmit) the i-ray spectrum with a narrowest bandwidth (for example, less than ± 10 nm width). . In contrast, the i-ray-broadband interference filter SWb is set to include only the bright-line wavelength of the i-rays, and the i-ray spectrum is extracted (transmitted) with the widest possible bandwidth. The bandwidth of the i-ray-broadband interference filter SWb is set depending on the chromatic aberration characteristics of a part of the projection optical system PLn (hereinafter, also referred to as a projection optical system only) of the reflection-refraction method described in the above embodiments. FIG. 28 shows the measurement of the wavelength characteristics of light generated by the arc discharge portion of the ultrahigh-pressure mercury discharge lamp shown in FIG. 5 using a spectroscope having a higher wavelength resolution than the spectroscope measuring the wavelength characteristics of FIG. 5. And obtain the detailed spectral characteristics. The main bright lines caused by the mercury of the ultra-high-pressure mercury discharge lamp are g-rays with a wavelength of 435.835 nm, h-rays with a wavelength of 404.656 nm, i-rays with a wavelength of 365.015 nm, and j-rays with a wavelength of 312.566 nm. Matter also produces a bright line Sxw (wavelength of about 330 nm) between the bright line wavelength of the i-ray and the bright line wavelength of the j-ray.

On the other hand, in the case of a projection optical system PLn, which is a reflection and refraction method, in the case of a projection optical system that mainly corrects the chromatic aberration of the bright-line wavelength of i-rays, its chromatic aberration characteristics tend to be as shown in FIG. FIG. 29 is a graph of the color difference characteristics obtained by taking the wavelength on the horizontal axis and the amount of color difference (magnification chromatic aberration, or color difference on the axis) on the vertical axis. When chromatic aberration correction is performed on the bright-line wavelength of i-rays, the lens elements constituting the projection optical system are made of two or more glass materials having different dispersion or refractive indices, so that the amount of chromatic aberration in the bright-line wavelengths of i-rays is made. Optical design in a way that essentially becomes zero. However, the chromatic aberration characteristic produces a large amount of chromatic aberration on the long wavelength region side and the short wavelength region side with respect to the bright line wavelength of the i-ray. Therefore, in terms of this chromatic aberration characteristic, the wavelength width ΔWi is set to be within the allowable amount ΔCAi as the amount of chromatic aberration, and does not include any obvious bright-line wavelength other than the i-ray. As shown in FIG. 28, there is a bright line Sxw beside the short wavelength side of the bright line wavelength of the i-ray, and there is an h-ray beside the long wavelength side, but there is no obvious bright line between the wavelengths of 340 nm to 400 nm . Therefore, the i-ray-broadband interference filter SWb has a characteristic of having a wavelength between about 350 nm and about 390 nm and a transmittance of 90% or more. That is, the i-ray-broadband interference filter SWb is set to a wavelength selection characteristic (transmission characteristic): peaks of strong bright lines appearing in each of the short-wavelength side and the long-wavelength side excluding the bright-line wavelength of the i-ray. The shape-like spectral component extracts (transmits) the spectral peak of the bright-line wavelength of the i-ray and the low-brightness spectral component distributed near its bottom. In addition, when using a projection optical system that corrects chromatic aberration at other bright-line wavelengths (h-rays or g-rays), it has more or less chromatic aberration characteristics as shown in FIG. 29, so the h-rays can be produced in the same manner. -Broadband interference filter or g-ray-broadband interference filter.

[Other variations]
As shown in FIGS. 4 and 15, in order to control the maximum divergence angles (maximum numerical apertures) of the illumination light beams BMa, BMb, and BMc on the respective incident ends FBi of the fiber bundles 12A, 12B, and 12C incident on the incident side, While the two groups of lens systems 8A1 and 8A2 with adjustable positions of the direction of the optical axis AX1 are provided, the magnification variable sections 8A, 8B, and 8C may be provided, but at least one of the lens systems 8A1 and 8A2 may be set to other lenses. The system switches and fixedly switches the method of the numerical aperture. In addition, between the lens system 8A1 of the previous group and the lens system 8A2 of the rear group, as disclosed in US Pat. No. 5,719,704, two conical cymbal-shaped optical members (rotary triplex optical system) may be provided. ). At this time, in the case of normal lighting, the two conical 稜鏡 -shaped optical members are closely contacted in the direction of the optical axis AX1, and in the case of annular lighting, the two conical ridges can also be adjusted. The interval between the directions of the optical axis AX1 of the mirror-shaped optical member, and the cross-sectional shape of the illumination light beam BMa passing between the lens system 8A1 and the lens system 8A2 is a ring shape with a variable size. In this case, it is not necessary to arrange a ring-shaped diaphragm plate APa ′ in the light path of the illumination beam, as in the fifth modification described with reference to FIG. 26, so the illumination light in the case of the ring-shaped illumination can be further improved. Utilization efficiency.

In each of the above embodiments or modifications, the fly-eye lens system FEn is used as the optical integrator, but a microlens array or a rod-shaped integrator may be used instead. Furthermore, in each of the above embodiments, mercury lamps (ultra-high-pressure mercury discharge lamps) 2A, 2B, and 2C are used as the light source devices, but any other discharge type lamps may be used. In addition, as the light source device, a laser light source such as a light emitting diode (LED), a solid laser, a gas laser, or a semiconductor laser can also be used; or the laser light of the seed light is amplified and generated by a wavelength conversion element A laser light source that is a harmonic of light (ultraviolet wavelength range).

Furthermore, it is added that, as a laser light source that generates harmonics of various kinds of light, for example, as a fiber amplifier laser light source disclosed in Japanese Patent Application Laid-Open No. 2001-085771, a pulsed laser light having a center wavelength of 355 nm can be used as illumination. beam. In this case, the wavelength conversion element for harmonic generation incorporated in a fiber amplifier laser light source or the like functions as a wavelength selection unit (wavelength selection element) that is the same as the interference filters SWa, SWb, and SWc. As a light source device, a mercury discharge lamp (ultra-high pressure mercury discharge lamp) and a laser light source may be used in combination. For example, the light from the mercury discharge lamp may include the spectrum of the i-ray (center wavelength: 365 nm) extracted by the i-ray-narrow-band interference filter SWa or the i-ray-broadband interference filter SWb. The component light is used in combination with a pulsed laser light having a center wavelength of 355 nm emitted from a fiber amplifier laser light source.

In the case of using the laser light source as described above, in order to set the divergence angle (numerical aperture) of the illumination light beam to be large, as an example, the light of the laser beam emitted as a parallel light beam from the laser light source may also be used. On the road, a wave plate diffraction grating made of glass material such as quartz is arranged, and a phase concavity and convexity of a fine concentric circle shape (wave plate shape) gradually decreasing in the diameter direction is formed. The minimum distance between the wave plate diffraction gratings is set according to the respective required divergence angles (numerical apertures) of the illumination light beams BMa, BMb, and BMc projected on the respective incident ends FBi of the fiber bundles 12A, 12B, and 12C.

In each of the above embodiments, the exposure device is described by taking a multi-lens scanning exposure device having a plurality of partial projection optical systems PLn as an example, but it may also be in a state where the mask substrate M and the plate P are stationary. A step-and-repeat type exposure apparatus that exposes the pattern of the reticle substrate M to sequentially move the plate P stepwise. The light source of the lighting device is not limited to three mercury lamps or three laser light sources, and may be provided with one, two, or four or more light sources. In the above embodiment, the six fiber bundles FGn having six emission ends FBo are used. However, in the case of an exposure device composed of one second illumination optical system ILn and one projection optical system PLn, the fiber bundle FGn may be one.

Furthermore, an illumination light beam BMa produced by a light source (mercury lamp 2A, etc.) and a first illumination optical system (including a wavelength selection unit 6A and a magnification variable unit 8A) is transmitted through a second illumination optical system IL1. When projecting on the reticle substrate M and projecting the pattern of the reticle substrate M through a part of the projection optical system PL1 and projecting and exposing it on the plate P, the fiber bundles 12A to 12C and FGn may not be provided, but the magnification will come from the magnification. The illumination light beam BMa of the variable section 8A directly passes through the first capacitor lens system CF1 of the second illumination optical system IL1 and enters the fly-eye lens system FE1.

According to the first embodiment or its modification, or the second embodiment described above, the light beam BM emitted from each of at least two of the first light source and the second light source (two of the mercury lamps 2A to 2C) is emitted. In the method of extracting the spectral distribution of a predetermined wavelength width, a first wavelength selection section and a second wavelength selection section (two of 6A to 6C) are provided, which are provided corresponding to each of the first light source and the second light source. ; The following mechanism (sliding mechanism FX, or mounting mechanism), which can be installed in each of the first wavelength selection section and the second wavelength selection section in an exchangeable manner to change the spectrum of the extracted wavelength region or wavelength width, etc. The distributed wavelength selection elements (interference filters SWa, SWb, SWc, etc.) are arranged in the optical path; and a light synthesis member (optical fiber bundle FGn) is used to convert the first illumination beam extracted by the first wavelength selection section and the first illumination beam Each of the second illumination light beams extracted by the two wavelength selection sections is synthesized using a numerical aperture variable section (two of 8A to 8C) and a numerical aperture set separately, and the illumination including an optical integrator is performed. Optical system A secondary light source image is formed on the illumination pupil surface. Therefore, according to the difference in the patterns on the reticle substrate (binary reticle, phase shift reticle, halftone reticle, etc.), the fineness of the pattern that should be exposed, and the development of the resist layer after development A variety of conditions (exposure recipes) such as the amount of taper inclination provided by the edge portion, or the reflectance change or unevenness in the case of a reflective mask pattern (different wavelength distribution characteristics within the distribution of the secondary light source image (each The intensity of the spectrum varies depending on the position within the illumination pupil plane), or the wavelength distribution is made different by the divergence angle corresponding to the maximum numerical aperture of the illumination beam to the mask substrate. Furthermore, by changing (switching) the wavelength distribution on the illumination pupil surface, it is also possible to control (suppress) the illumination variation (projection magnification variation, focus variation, aberration variation, etc.) of the projection optical system itself. The pattern of the reticle substrate is generated by the energy of the imaging beam passing through the projection optical system (part of the projection optical system PLn) for projection exposure.

Hereinafter, referring to FIG. 30, the wavelength characteristics (spectral characteristics) of the light from the mercury discharge lamp will be supplemented. In each embodiment or modification, a short arc type ultra-high-pressure mercury discharge lamp (2A, 2B, 2C) is mainly used, but as a light source of a pattern exposure device for electronic components, mercury vapor in a discharge tube (light-emitting tube) is also used. A high-pressure mercury discharge lamp with a pressure of about 10 ⁵ Pa to 10 ⁶ Pa. Generally, an ultra-high-pressure mercury discharge lamp raises the mercury vapor pressure in the discharge tube to about 10 ⁶ Pa to about 10 ⁷ Pa, thereby making i-rays, h-rays, and g-rays suitable for the bright-line wavelength of light lithography. Each spectral width is slightly expanded compared with a high-pressure mercury discharge lamp, or the relative balance of the peak intensities of i-rays, h-rays, and g-rays is different from that of a high-pressure mercury discharge lamp. In the discharge tube of a mercury discharge lamp, for example, as disclosed in Japanese Patent Application Laid-Open No. 2009-193768, except for mercury (0.15 mg / mm ³ or more) whose mercury vapor pressure reaches 150 to 300 at the time of lighting, Halogens such as iodine, bromine, and chlorine are enclosed in the form of a compound of about 13 kPa of argon (a rare gas) and mercury or other metals. Furthermore, compared with the high-pressure mercury discharge lamp, the light from the ultra-high-pressure mercury discharge lamp is also compared with the light intensity of the bright-line wavelength in the wavelength band between each bright-line wavelength i-ray, g-ray, and h-ray. A peak has a relatively low-brightness spectral distribution (a portion near the bottom) of several% or about 10 to 20%.

FIG. 30 is a graph explaining the difference in wavelength characteristics between a high-pressure mercury discharge lamp and an ultra-high-pressure mercury discharge lamp. FIG. 30 (A) shows an example of the wavelength characteristics of light from a high-pressure mercury discharge lamp, and FIG. 30 (B) shows An example of the wavelength characteristics of light from an ultrahigh-pressure mercury discharge lamp. In each of FIGS. 30 (A) and 30 (B), the horizontal axis represents the wavelength (nm), and the vertical axis represents the relative intensity (%) of the spectrum when the peak value of the intensity of the i-ray at the bright line is set to 100%. . Although the wavelength characteristics of each of Figures 30 (A) and (B) vary depending on the difference between the lamp manufacturer and the rated power of the lamp, the wavelength of the wavelength including the i-ray (365 nm) is 350 to 400. At the spectral distribution of nm, in the high-pressure mercury discharge lamp, as shown in FIG. 30 (A), there is basically no near-bottom portion with a relative intensity of several% or more, preferably 10% or more. In contrast, in the ultra-high pressure mercury discharge lamp, as shown in FIG. 30 (B), a portion near the bottom (a low-brightness spectral component) having a relative intensity of several% or more and approximately 10% appears.

The relative intensity of the vicinity of the bottom of the i-ray in FIG. 30 (B) can vary depending on the amount of mercury enclosed in the discharge tube, the type or content of other noble gases or halogens, and the mercury vapor pressure, and becomes a few% to 20 %about. The spectral widths of i-rays, h-rays, and g-rays with bright-line wavelengths tend to slightly expand (thicken) the ultrahigh-pressure mercury discharge lamp of FIG. 30 (B) than the high-pressure mercury discharge lamp of FIG. 30 (A). In addition, in the wavelength characteristics shown in FIG. 5, the spectral component in the range of 350 to 400 nm near the bottom of the wavelength (365 nm) of the i-ray is relatively 20% relative to the peak intensity of the i-ray. The intensity.

Therefore, in a manner that only includes the i-rays in the bright-line wavelength of mercury, the i-ray-broadband interference filter SWb shown in FIG. 7 is used to perform the wavelength-selected illumination beam (BSa, BSb, BSc). Compared with the illumination beam whose wavelength is selected using the i-ray-narrow-band interference filter SWa shown in FIG. 6 described above, the amount of light energy is increased. Even with respect to the peak intensity of the i-ray, the relative intensity of the vicinity of the bottom of the i-ray (in the range of 350 nm to 365 nm and 365 nm to 400 nm) is about 10% as shown in Figure 30 (B). The amount of light energy (dosage) per unit time provided by the resist layer only increases approximately by the amount determined by the product of the intensity near the bottom and the wavelength width, so the exposure is increased by about 20% (1.1 × 1.1 ≒) 1.2 times). Therefore, when the pattern of the photomask substrate M is scanned and exposed on the resist layer of the plate P by using the exposure device EX shown in FIG. 1, the scanning speed of the photomask substrate M and the plate P can be increased by about 20%. As a result, the productivity of the step of exposing the pattern using the high resolution of the i-ray can be improved by about 20%.

Therefore, the wavelength width at 10% of the relative intensity of the spectral distribution of the i-rays emitted by the high-pressure mercury discharge lamp shown in FIG. 30 (A), or the i-ray-narrow-band interference filter SWa shown in FIG. 6 The wavelength selection range (bandwidth) set in is set to BWi (nm). The wavelength width (bandwidth) is set so that the wavelength reaching the peak intensity is centered in the spectral distribution of the i-rays emitted by the ultra-high pressure mercury discharge lamp. When BWi is outside the BWi (short wavelength side and long wavelength side) and reaches the spectrum of the bright line wavelength next to it as the vicinity of the bottom, the average relative intensity of the vicinity of the bottom may be several% to 10% ( It is ideally more than 20%) to adjust the mercury pressure and mercury vapor pressure, the pressure or composition of rare gases, the composition of halogen, and other ultra-high-pressure mercury discharge lamps. In addition, it is not limited to the spectral distribution of i-rays. When the spectral distribution of h-rays or g-rays from an ultra-high pressure mercury discharge lamp is used, it is also compared with the h-rays or g-rays from a high-pressure mercury discharge lamp. The expansion occurs in the vicinity of the bottom portion where the relative intensity becomes several%. Therefore, it is only necessary to prepare an h-band interference filter or a g-band interference filter having a wavelength selection characteristic including the vicinity of the bottom portion.

Next, a modification of the photomask is added. In each of the above embodiments or modifications thereof, the premise is that an exposure device in which a transmissive or reflective photomask substrate (or cylindrical photomask) having a photomask pattern fixedly formed (supported) is used. The mask-type exposure device (because it does not use a fixed mask pattern, it is also called a maskless exposure device) can also be applied to the lighting system described in each embodiment (Figures 3 to 20, etc.). The variable-mask-type exposure device uses a DMD (Digital Mirror Device) or the like that two-dimensionally arranges a plurality of micro-mirrors, and switches the mirrors at a high speed according to the data (CAD data) of the pattern to be exposed. Their respective angles, thereby projecting a pattern image on the plate P. In the variable-mask-type exposure device, the projection area formed by one DMD on the plate P is the same as the projection area EA1 shown in FIG. 1 and is limited to a small rectangular area. Therefore, a plurality of DMDs are provided, and The reflected light of each DMD is projected on a plurality of projection lens systems on the plate P. In this case, the respective reflection surfaces of the plurality of DMDs (the surfaces in which a plurality of minute mirrors are arranged) are in the form of a distribution of a plurality of minute mirrors that individually control the reflection direction of light based on CAD data, and are supported by Patterns for electronic components. Moreover, the respective reflection surfaces of the plurality of DMDs are arranged at positions corresponding to the illumination areas IA1 to IA6 shown in Figs. 1 to 3, and the intensity of the illumination beam is uniformized within an intensity distribution within, for example, ± 2% (as shown in Fig. 14). The BSa ', BSb', and BSc 'shown in the figure are equivalent) and irradiated.

Therefore, it is possible to reflect the minute mirrors whose angles are set in such a manner that the illumination light beams are projected into the projection lens system from the plurality of DMD micromirrors, and the projection light beams (illumination beams) projected on the plate P through the projection lens system. ) Has the same characteristics as the alignment characteristics (divergence angle characteristics) shown in FIG. 20. Furthermore, the combination of the interference filter shown in FIG. 21 can also be used to make the wavelength distribution within the divergence angle corresponding to the maximum numerical aperture of the projection beam irradiated onto the plate P from each of the tiny mirrors of the DMD. different. In addition, instead of DMD, a Spatial Light Modulator (SLM: Spatial Light Modulator) can also be used, which is based on the selection of reflective surfaces (usually all set on the same plane) of a plurality of tiny mirrors arranged in two dimensions. The tiny mirror is displaced in a direction perpendicular to the reflecting surface to give a phase difference to the reflected beam.

Second, it supplements other forms of the projection exposure apparatus. In the above-mentioned embodiment or modification, the so-called multi-lens type exposure device provided with a plurality of partial projection optical systems PLn (PL1 to PL6) and corresponding second illumination optical systems ILn (IL1 to IL6) is assumed. However, even if an exposure device having a single projection optical system and a single second illumination optical system is assumed, it is easy to have the same function only by slightly changing the configuration in the above embodiment. Specifically, in the line distribution section 10 a in the light distribution section 10 shown in FIG. 9 described above, a plurality of optical fiber wires included in each of the incident side optical fiber bundles 12A, 12B, and 12C are not distributed to six optical fiber bundles. Each of FG1 to FG6 can be aggregated into a single optical fiber bundle, and it can be formed into a rectangular shape similar to the shape of a single illumination area where the exit end FBo of the single optical fiber bundle is set on the mask substrate M.

Next, a modification of the light source device is added. In the structure of FIG. 3 described above, a plurality of (two or more) mercury discharge lamps 2A, 2B, and 2C are used as the light source device. However, in the case of using a single ultrahigh-pressure mercury discharge lamp, the above can be changed only slightly. The structure in the embodiment can easily have the same function. Specifically, a dichroic mirror is provided. The light from a single ultra-high-pressure mercury discharge lamp is converted into a substantially parallel beam by a lens system (collimating lens) 6A1 in FIG. 4, for example, an i-ray will not be included. In the wavelength region of the spectral component, light in the wavelength band including the spectral component of the h-ray and the spectral component of the g-ray is transmitted, and light in the short wavelength band including the spectral component of the i-ray is reflected. Further, for the light transmitted from the dichroic mirror, a wavelength selection section 6A (for example, an interference filter including an extraction of spectral components of h-rays) and a magnification variable section 8A are provided as shown in FIG. 4 (or FIG. 3). For the light reflected by the dichroic mirror, a wavelength selection section 6B (including an i-ray-narrow-band interference filter SWa or an i-ray-broadband interference filter SWb) and a magnification variable section 8B are provided. In this way, similar to the description of FIG. 22, the illumination pupil surface (equivalent to the exit surface epi of the fly-eye lens system FEn) in the second illumination optical system ILn can be formed with a two-dimensional extension (range). The wavelength characteristic of the light source image (convergence of the point light source image) is variable according to the characteristics of the interference filter selected and set.

Next, the setting of the wavelength selection characteristic using the i-broadband interference filter SWb is supplemented. As shown in FIG. 30 (B), the width of the portion near the bottom of the spectral component of the i-ray from the ultra-high-pressure mercury discharge lamp (for example, a range of intensity of about 10% relative to the peak intensity at the center wavelength of the i-ray) ) Compared with the width of the portion near the bottom of the spectral component of the i-ray from the high-pressure mercury discharge lamp shown in FIG. 30 (A), it has an expansion of more than two times. Part of the projection optical system PL1 (PL2 to PL6) of the exposure device EX shown in Figs. 1 and 2 above is a reflection and refraction method in which mirrors Ga4 and Gb4 are arranged on the pupil plane (aperture position) Epa and Epb. Half-field type imaging system. This imaging system has the advantage of easier correction of chromatic aberration compared to the imaging system of the total refraction method (all optical elements are only composed of refractive elements such as lenses). It uses an optical system that includes multiple bright-line spectra (such as i-ray spectral components). And h-ray spectrum components), when the pattern of the mask M is projected and exposed on the substrate P, the degradation (image distortion) of the projected image caused by chromatic aberration can also be reduced.

However, even if the projection exposure is performed using only the illumination light of a single i-ray spectral component narrowed by the i-narrow-band interference filter SWa, if the pattern formed on the mask M becomes fine, The projection image (image intensity distribution) is distorted due to various aberrations of the projection optical system PL1 (PL2 to PL6). The apparent distortion is a fine isolated rectangular (roughly square) pattern called a hole pattern.

FIG. 31 schematically shows a projection image (light intensity distribution) obtained when a square hole pattern formed on the reticle M is projected on a substrate P using an i-ray-narrow-band interference filter SWa. A graph showing the relationship between the shape of the resist or the shape of the resist image appearing by the development of the exposed resist layer. The X-axis and Y-axis systems correspond to the above-mentioned orthogonal coordinate system XYZ in FIGS. 1 to 3. . Here, FIG. 31 (A) schematically shows a hole pattern CHA formed on the mask M with a size Dx × Dy sufficiently larger than the minimum line width value analyzed by the projection optical system PL1 (PL2 to PL6). The shape of the projection image (resist image) Ima obtained in this case; FIG. 31 (B) schematically shows the case of the hole pattern CHB formed on the mask M with a size of about twice the minimum line width value. The shape of the projection image (resist image) Imb obtained at that time; FIG. 31 (C) schematically shows the case of the hole pattern CHC formed on the mask M with a size close to the minimum line width value. The shape of the projected image (resist image) Imc. In FIG. 31, the hole patterns CHA, CHB, and CHC are all formed as isolated transparent portions in the surrounding light-shielding portions indicated by hatching, but the opposite case may also be formed as isolated light-shielding portions. In the surrounding transparent part. In addition, the resolution R, which is expressed as the minimum line width value that can be projected by the projection optical system PLn (n = 1 to 6), is usually determined by the numerical aperture NAp on the image side of the projection optical system PLn and the wavelength λ (nm of the illumination light). ), A program constant k (0 <k ≦ 1), and defined by R = k · (λ / NAp).

As shown in FIG. 31 (A), when the minimum line width value that can be projected by the projection optical system PLn is a large square hole pattern CHA with a size Dx × Dy several times or more, the corner portion of the right corner of the four corners The value of the numerical aperture NAp on the image side of the projection optical system PLn, that is, the MTF (Modulation Transfer Function), is mainly circular without being fully analyzed. This phenomenon also occurs when illumination light (for example, laser light with a spectral width of less than 1 nm, etc.) having an extremely narrow extension of the spectral distribution of the center wavelength λ is used. In particular, as shown in FIG. 31 (C), in the case of a square hole pattern CHC having a size close to the minimum resolvable minimum line width value of the projection optical system PLn, the shape of the projection image (resist image) Imc is roughly Become round. Under the characteristics of such a projection optical system PLn, if an i-ray-broadband interference filter SWb as shown in FIG. 7 is used, the near-bottom portion of the spectral distribution is widely included with respect to the center wavelength of the i-ray. When the illumination light extracted by the method is projected to expose the hole pattern CHC shown in FIG. 31 (C), the projection image (resist image) Imc changes from circular to oval due to the chromatic aberration characteristics of the projection optical system PLn. .

FIG. 32 is an exaggerated state of the projected image Imc deformed as described above, and the dotted line in FIG. 32 indicates the projected image Imc ′ which is a substantially correct circle. The circular diameter of the projection image Imc 'can also be theoretically estimated from the basic optical characteristics of the projection optical system PLn. The short-axis length of the Y-axis direction of the projected image Imc distorted into an ellipse due to the influence of chromatic aberration is set to CHy, the long-axis length of the X-axis direction is set to CHx, and the oblateness (ellipticity) Δf of the ellipse When it is set to Δf = CHy / CHx, the flatness (ellipticity) Δf should be set to 80% or more, and more preferably 90% or more, in terms of the allowable range in component manufacturing. That is, the extended range near the bottom of the spectral distribution of the i-rays extracted by the i-ray-broadband interference filter SWb is defined as: the square hole pattern CHC of a size close to the smallest resolvable line width value The shape distortion of the projected image Imc from a circle is limited to an ellipse with an oblateness (ellipticity) of 80% or more, and more preferably 90% or more.

In FIG. 32, in the elliptical deformation of the projected image Imc, the long-axis direction is shown as the X direction, and the short-axis direction is shown as the Y direction. The directions of the long-axis and short-axis are sometimes shown in FIG. 33. The XY plane faces in any direction. In FIG. 33, the long axis and the short axis of the projection image Imc deformed into an oval hole pattern are rotated by Δρ with respect to the X axis and the Y axis. Therefore, in order to accurately determine the appropriateness of the extended range near the bottom of the spectral distribution of the i-rays extracted by the i-ray-broadband interference filter SWb, the test and exposure are used to minimize the resolution. The projection image Imc of the square hole pattern CHC with a line width value close to the size is exposed on the substrate P, and an inspection device is used to observe the developed resist image corresponding to the projection image Imc, and image analysis software is used. Then, the shape of the resist image corresponding to the projected image Imc is determined (determining the directions of the major axis and the minor axis), and the major axis length CHx in the major axis direction and the minor axis length CHy in the minor axis direction are measured. Furthermore, it is only necessary to determine whether the oblateness (ellipticity) Δf obtained from the measurement results is within an allowable range (80% or more, and more preferably 90% or more).

However, as shown in FIG. 2 described above, in the image space of the imaging optical path of the projection optical system PLn (n = 1 to 6) (the closest place below the field diaphragm plate FA1 on the intermediate image plane IM1), Image shift optical member SC1. The image-shifting optical member SC1 is, as disclosed in, for example, International Publication No. 2013/094286, a transparent parallel plate glass (quartz plate) that can be tilted in the XZ plane in FIG. 2 and a direction orthogonal to the plate glass (quartz plate). It is composed of a tilted transparent parallel plate glass (quartz plate). By adjusting the respective inclination amounts of the two quartz plates, the pattern image in the projection area EA1 (EA2 to EA6) projected on the substrate P can be slightly shifted in any direction in the XY plane. In addition, the configuration of the image-shifting optical member SC1 is not limited to the nearest position below the field diaphragm plate FA1 shown in FIG. 2, and the optical member FC1 or magnification can be adjusted with the focal point of the other correction optical system arranged in the image space. The arrangement of any one of the optical members MC1 is adjusted and replaced.

Each of the two parallel flat quartz plates constituting the image-shifting optical member SC1 has a high transmittance from the ultraviolet wavelength region (about 190 nm) to the visible wavelength region, but in the case of synthetic quartz, as an example, as shown in the figure As shown in 34, the refractive index tends to vary greatly depending on the wavelength from a short-wavelength region with a wavelength of 500 nm or less, particularly from the vicinity of the wavelength of 400 to 3000 nm to the short-wavelength side. In FIG. 34, the horizontal axis represents the wavelength (nm), and the vertical axis represents the refractive index of the synthetic quartz. Therefore, for example, when using light from an ultra-high-pressure mercury discharge lamp (or a high-pressure mercury discharge lamp), two of the i-ray spectral component with a center wavelength of about 365 nm and the h-ray spectral component with a center wavelength of about 405 nm are included. When the illumination light of a person projects the pattern of the mask M, an image projected on the substrate P with an i-ray spectral component and an h-ray spectrum are generated according to the tilt amount of the quartz plate of the image shift optical member SC1. The image of the component projected on the substrate P is slightly shifted in the XY plane.

FIG. 35 is a diagram schematically showing an operation of an imaging beam in a quartz plate SCx that displaces an image in the X direction in two quartz plates constituting the image shift optical member SC1 disposed under the field stop plate FA1. The quartz plate SCx is configured such that the incident surface Stp into which the imaging light beam of the opening portion of the transmission field diaphragm plate FA1 enters and the emitting surface Sbp from which the imaging light beam is emitted are opposed to each other at an interval (thickness) Dpx. It can rotate (tilt) around the rotation center line parallel to the Y axis. In FIG. 35, only the main ray Lpr of the imaging beam that travels from the image point Poc that is imaged on the center point of the opening of the field diaphragm FA1 as an intermediate image and diverges from the imaging beam, and the line Lss represents the main beam. The normal to the incident surface Stp at the point where the light LPR intersects the incident surface Stp, and the line L Pr 'represents the extension of the main light LPR before incident on the incident surface Stp. With respect to the state in which the incident surface Stp of the quartz plate SCx is orthogonal to the incident main ray Lpr (state where the inclination of the quartz plate SCx is zero), if the quartz plate SCx is inclined at an angle Δθx in the XZ plane, then According to Snell's law, the main light beam L Pr is emitted from the emission surface Sbp in the X direction, and is shifted by a parallel shift amount δx relative to the extension line L Pr ′.

Generally, the amount of light displacement δx caused by the inclination of the parallel plate glass with refractive index nx can be calculated by applying Senna's law and δx ≒ Dpx · Δθx (1-1 / nx), but i is included in the imaging beam. In the case of the ray spectral component (wavelength 365 nm) and the h-ray spectral component (wavelength 405 nm), the refractive index of the quartz plate SCx shows slightly different values with respect to the respective wavelengths. Therefore, if the refractive index in the i-ray spectral component (wavelength 365 nm) of the quartz plate SCx is set to ni and the refractive index in the h-ray spectral component (wavelength 405 nm) is set to nh, the i-ray spectral component (wavelength 365) The displacement of the image caused by nm) is set to δxi, and the displacement of the image caused by the h-ray spectral component (wavelength 405 nm) is set to δxh, then the displacement amount δxi is δxi ≒ Dpx · Δθx (1－1 / ni), and the displacement amount δxh is calculated by δxh ≒ Dpx · Δθx (1−1 / nh). Therefore, if the difference in the amount of displacement caused by the difference in wavelength (color shift) is δx (i-h), the difference δx (i-h) becomes δx (i-h) ≒ Dpx · Δθx [ (1-1 / ni)-(1-1 / nh)].

As an example, if the thickness Dpx of the quartz plate SCx is 10 mm, the refractive index ni of the i-ray spectral component (wavelength 365 nm) is set to 1.4746, and the refractive index nh of the h-ray spectral component (wavelength 405 nm) is set It is 1.4696 to obtain the change in the difference δx (i-h) with respect to the angle Δθx (0 ° to 10 °), and it becomes a linear characteristic like the graph shown in FIG. 36. In the graph of FIG. 36, the horizontal axis represents the inclination angle Δθx [deg.] Of the quartz plate SCx, and the vertical axis represents the difference δx (i-h) [μm]. The quartz plate SCx is disposed in the image space forming the intermediate image, and the projection magnification of the projection optical system PLn is equal (× 1). Therefore, the difference δx (i-h) in FIG. 36 is directly projected onto the substrate P. The relative positional offset between the pattern image caused by the i-ray spectral component and the pattern image caused by the h-ray spectral component. For example, when the inclination angle Δθx of the quartz plate SCx is 5 °, the difference δx (i-h) caused by the color shift becomes about 2 μm in the x direction, and the pattern exposed by the projection is distorted, or Line width causes errors.

The effect of the color shift caused by the quartz plate SCx described above also occurs on other quartz plates (set to SCy) that slightly shift the projection image in the Y direction. If the quartz plate SCy is parallel to the X axis, The angle of inclination Δθ from the horizontal initial state around the rotation center line produces a difference δy (i-h) caused by the color shift in the Y direction. As described above, when the illumination light is improved by the illumination light including both the i-ray spectral component (wavelength 365 nm) and the h-ray spectral component (wavelength 405 nm), in order to use the projection optical system PLn (n = 1 Each of the image shift ranges caused by the image shift optical member SC1 that maintains the continuous accuracy between the pattern images projected on the substrate P to be good and has a difference amount δx ( i-h), δy (i-h), and are restricted.

On the other hand, as in the above-mentioned embodiments or modifications, by using the i-ray-broadband interference filter SWb, the portion near the bottom of the i-ray spectral component of the ultra-high-pressure mercury discharge lamp as shown in FIG. 7 can be obtained. It is widely extracted within the range that does not include the bright line component (h-ray) on the long-wavelength side or the bright line component on the short-wavelength side, and can be compared with the illuminance when using the i-ray-narrowband interference filter SWa. In order to improve the illuminance of several% to ten%, the color shift error [and difference components δx (i-h), δy (i -H) equivalent error] suppressed to small.

In addition, the flatness (ellipticity) Δf when the projection image Imc of the hole pattern CHC described in Figs. 32 and 33 described above is distorted into an ellipse, or the directivity in the XY plane of the long axis / short axis also follows the image. The degree of inclination of the quartz plates SCx and SCy of the offset optical member SC1 varies. Therefore, as in the projection optical system PLn shown in FIG. 2, when an image shift optical member SC1 using a tiltable parallel plate glass (quartz plate SCx, SCy) is provided, the image shift optical member SC1 is used. The maximum inclination angles Δθx, Δθy of the parallel flat glass (quartz plates SCx, SCy) caused by the maximum amount of nominal image shift can also be approximated by the minimum line width value (resolution R) The flatness (ellipticity) Δf of the projection image Ic of the pattern CHC is set to be 80% or more (preferably 90% or more) in theory or actual exposure. Set the wavelength selection of the i-broadband interference filter SWb. range.

Based on the above, in the embodiment described in FIGS. 31 to 36, the mask pattern (transmission type or reflection type) is performed by using illumination light with a predetermined wavelength distribution (for example, light from an ultra-high pressure mercury discharge lamp). A projection optical system for illuminating and projecting an imaging beam generated by a mask pattern onto a substrate, projecting and exposing an image of the mask pattern on a substrate, and projecting a specific center in a wavelength distribution of the illumination light The wavelength is set to λ (for example, the central wavelength of i-rays), the numerical aperture on the substrate side of the projection optical system is set to NAp, and the program constant is set to k (0 <k ≦ 1). NAp) The projection image of the square or rectangular hole pattern with the smallest resolvable minimum line width size close to the resolution defined by NAp is projected on the substrate. The short axis length of the projection image transformed into an oval hole pattern. (CHy) The ratio (CHy / CHx) to the long axis length (CHx) is 80% (0.8) or more, preferably 90% (0.9) or more. The wavelength distribution of the illumination light including the central wavelength λ is set. Width (e.g. by The wavelength width selected by the interference filter) can increase the illuminance of the illuminating light that illuminates the mask pattern, and can perform high-resolution pattern exposure. In addition, the size of the hole pattern is set to a size converted into an image projected on the substrate side, which is larger than the size determined by the resolution force R and smaller than 2 times the resolution force R.

In other words, as an interference filter that filters light from a light source (mercury discharge lamp, etc.) that emits light including a plurality of bright lines into illumination light having a wavelength width suitable for projection exposure of a mask pattern, An interference filter is set in the illumination system of the exposure device to set the filtering wavelength width as follows: set the center wavelength of a specific bright line in the wavelength distribution of the illumination light to λ (for example, the center wavelength of an i-ray), and project The numerical aperture on the substrate side of the optical system is set to NAp, the program constant is set to k (0 <k ≦ 1), and the minimum resolvable minimum line width dimension determined by the resolution force R defined by k · (λ / NAp) is close to When the projection image of a large square or rectangular hole pattern is projected on a substrate, the ratio of the short axis length CHy of the projection image deformed into an oval hole pattern to the long axis length CHx CHy / CHx becomes 80% (0.8) or more, More preferably, it is above 90% (0.9).

2A, 2B, 2C‧‧‧ Mercury lamps

4A, 4B, 4C‧‧‧ ellipse

5A, 5B, 5C‧‧‧Rotary shutter

6A, 6B, 6C‧‧‧Wavelength selection section

6A1, 6A2 ‧‧‧ lens system

8A, 8B, 8C‧‧‧Magnification variable section

8A1, 8A2, 8B1, 8B2, 8C1, 8C2‧‧‧ lens system

10‧‧‧Light Distribution Department

10a‧‧‧line distribution department

12A, 12B, 12C‧‧‧ Fiber Bundle

APa, APb ‧ ‧ iris plate

APa'‧‧‧ annular band diaphragm plate

AX1, AX2, AXa, AXb‧‧‧ Optical axis

BM, BMa, BMb, Bmc‧‧‧ beam

BSa, BSa ', BSb, BSb', BSc, BSc'‧‧‧ illumination beams

CC1, CC2‧‧‧ Centerline

CCA‧‧‧ circular area

CCp‧‧‧center plane

CFn (CF1 ~ CF6) ‧‧‧Capacitor lens system

CFa, CFb, CFc ‧‧‧ area

CHA, CHB, CHC‧‧‧hole pattern

CHx‧‧‧Long axis length

CHy‧‧‧ short axis length

CPn (CP1 ~ CP6) ‧‧‧Capacitor lens system

DM‧‧‧Dual color mirror

DMM‧‧‧Cylinder Mask

Dpx‧‧‧thickness

DR‧‧‧Rotary

EA1‧‧‧ projection area

Epa, Epb ‧‧‧ pupil surface

epi‧‧‧ shoot out

Ewa, Ewb‧‧‧Edge

EX‧‧‧Exposure device

FA1‧‧‧field diaphragm

FBi‧‧‧incident side

FBo‧‧‧ Injection

FC1‧‧‧ Focus Adjustment Optical Component

FEn (FE1 ~ FE6) ‧‧‧Flying Eye Lens System

FGn (FG1 ~ FG6) ‧‧‧Fiber Bundle

FS‧‧‧chip substrate

FX‧‧‧ sliding mechanism

Ga1, Ga2, Ga3, Gb1, Gb2, Gb3 ‧‧‧ lens system

Ga4, Gb4 ‧‧‧ concave mirror

HL‧‧‧Opening

IAn (IA1 ~ IA6) ‧‧‧Lighting area

ILn (IL1 ~ IL6) ‧‧‧Lighting optical system

IM1‧‧‧Intermediate image plane

Ima, Imb, Imc, Imc'‧‧‧ cast images

Irn‧‧‧illuminating beam

LDa, LDb‧‧‧light source image

Le‧‧‧ lens element

Lpi, L Pr‧‧‧ principal rays

LPr'‧‧‧ extension cable

Lss‧‧‧line

Luv‧‧‧ resist layer

M‧‧‧Photomask substrate

MC1‧‧‧Magnification adjustment optical component

NAd1‧‧‧Maximum numerical aperture

NAd2‧‧‧ Hollow numerical aperture

NAia, Naib, NAic, NAα, NAβ ‧‧‧ NA

OP‧‧‧point

P‧‧‧board

PBSa, PBSb‧‧‧ Polarized Beamsplitters

PL1 ~ PL6‧‧‧‧partial projection optical system

PL1a‧‧‧The first imaging system

PL1b‧‧‧2nd imaging system

PMa, PMb‧‧‧ 稜鏡

Poc‧‧‧like points

poi‧‧‧ incident surface

PS1, PS2‧‧‧ focus position

Ria, Rib, Ric ‧‧‧ radius

RT‧‧‧ thickness

Sbp‧‧‧ Projection

SC1‧‧‧Phase Shifting Optical Component

SCx‧‧‧Quartz Plate

SPa, SPa ', SPb, SPb', SPc, SPc'‧‧‧point light

Stp‧‧‧ incident surface

SWa, SWb, SWc‧‧‧i-ray + h-ray-interference filter

Sxw‧‧‧ Open Line

TPa‧‧‧Loop-shaped light transmitting part

TPb‧‧‧fan-shaped light transmitting part

ΔCAi‧‧‧Allowable

ΔHx, ΔHy‧‧‧ distance

ΔWi‧‧‧ Wavelength Width

δx‧‧‧Displacement

FIG. 1 is a perspective view showing a schematic configuration of a scanning projection exposure apparatus according to a first embodiment.

FIG. 2 is a diagram showing the arrangement of optical components of a projection optical system incorporated in the projection exposure apparatus shown in FIG. 1. FIG.

3 is a perspective view showing a schematic overall configuration of an illumination device for irradiating a mask substrate mounted in the projection exposure device shown in FIG. 1 with exposure illumination light.

FIG. 4 is a perspective view schematically showing a configuration of a first illumination optical system from a mercury lamp to an optical fiber (optical fiber bundle) in the lighting device shown in FIG. 3.

FIG. 5 is a graph schematically showing an example of a wavelength characteristic (spectral distribution) of light generated by arc discharge of an ultrahigh-pressure mercury discharge lamp.

FIG. 6 is a graph schematically showing a state in which light with a narrow wavelength width of i-rays is selectively extracted from the wavelength characteristics (spectral distribution) shown in FIG. 5 by an i-ray-narrow-band interference filter.

FIG. 7 is a view schematically showing a light beam having a wide wavelength width including i-rays and a portion near the bottom thereof selectively extracted from the wavelength characteristics (spectral distribution) shown in FIG. 5 by an i-ray-broadband interference filter. Status chart.

FIG. 8 is a diagram schematically showing light with a wide wavelength width including both i-rays and h-rays from the wavelength characteristics (spectral distribution) shown in FIG. 5 by an i-ray + h-ray-interference filter Status chart.

FIG. 9 is a perspective view schematically showing the overall configuration of an optical fiber (optical fiber bundle) installed in the lighting device shown in FIG. 3 and the shape of each of an incident end and an emission end.

FIG. 10 is a perspective view schematically showing a configuration of a second illumination optical system in the illumination device shown in FIG. 3, which irradiates illumination light from an exit end of a fiber bundle to an illumination area on a mask substrate.

FIG. 11 is a diagram schematically showing a state of illumination light in an optical path from the exit end of the optical fiber bundle shown in FIG. 10 to the fly-eye lens system.

FIG. 12 is a diagram schematically showing an example of an arrangement of a plurality of point light source images formed on each optical fiber line at the exit end of the optical fiber bundle shown in FIG. 11.

FIG. 13 is a diagram showing an arrangement state of a plurality of point light source images formed at respective emitting ends of a plurality of lens elements constituting the fly-eye lens system shown in FIG. 11.

14 is a diagram schematically showing a state of illumination light in an optical path from the fly-eye lens system shown in FIG. 10 to an illumination area on a mask substrate.

FIG. 15 is a diagram explaining the effect of adjusting the numerical aperture (divergence angle) of the illumination light beam irradiated on the incident end of the optical fiber bundle by the variable magnification section (numerical aperture variable section) shown in FIG. 4.

FIG. 16 is a diagram schematically showing a state of a light beam incident on three fiber bundles on the incident side of the fiber bundle shown in FIG. 9 and an illumination light beam emitted from the six fiber bundles on the exit side.

FIG. 17 is a schematic view of the optical path from the exit end of the optical fiber bundle to the incident surface of the fly-eye lens system as viewed from the X direction (scanning movement direction).

FIG. 18 is a diagram showing the states of the circular regions CFa, CFb, and CFc in FIG. 17 distributed on the incident surface of the fly-eye lens system in the XY plane.

FIG. 19 (A) is a diagram showing the distribution of point light (point light source image) formed on the exit surface of the fly-eye lens system from the X direction (scanning movement direction), and FIG. 19 (B) is from the Y direction (stepping (Moving direction) to see the distribution of point light (point light source image) formed on the exit surface of the fly-eye lens system.

FIG. 20 is a diagram schematically showing an alignment characteristic (a characteristic of a divergence angle) of an illumination light beam Irn irradiated to a point OP on an illumination area on a mask substrate.

FIG. 21 is the i-ray-narrow-band interference filter SWa of FIG. 6, the i-ray-broadband interference filter SWb of FIG. 7, and FIG. The combination examples of the i-ray + h-ray-interference filter SWc are summarized in the table.

FIG. 22 is a graph schematically showing the wavelength characteristics of the illumination beam of the mask substrate obtained by the combination of the interference filters represented by the combination code B2 in the table of FIG. 21.

FIG. 23 is a graph showing an example of the light absorption characteristics of the negative-type photoresist depending on the wavelength for the explanation of the modification 3. FIG.

FIG. 24 is a cross-sectional view schematically showing an inclination generated at an edge portion (side wall) of a resist image of a residual film after development for the explanation of Modification Example 3. FIG.

FIG. 25 (A) is a diagram showing a configuration of Modification Example 4 and showing the shape of a diaphragm plate APa having an endless belt-shaped light-transmitting portion, and FIG. 25 (B) is a diagram showing a configuration of Modification Example 4 and shows that Figure of the shape of the diaphragm plate APb of the quadrupole-shaped light-transmitting portion.

FIG. 26 is a diagram showing a configuration of Modification 5 and showing a state in which a ring-shaped diaphragm plate is arranged on the wavelength selection section 6A of the first illumination optical system.

FIG. 27 is a diagram showing a schematic overall configuration of an exposure apparatus according to a second embodiment.

FIG. 28 is a graph showing the detailed spectral characteristics obtained when the wavelength characteristics of the ultrahigh-pressure mercury discharge lamp shown in FIG. 5 are measured using a spectroscope with a high wavelength resolution.

FIG. 29 is a graph showing the relationship between the chromatic aberration characteristic of the projection optical system and the bright line wavelength of the i-ray of the mercury lamp.

FIG. 30 is a graph illustrating differences in wavelength characteristics between a high-pressure mercury discharge lamp and an ultra-high-pressure mercury discharge lamp.

FIG. 31 is a diagram illustrating distortion of the shape of a projection image obtained when a hole pattern having different sizes formed on a photomask is projected on a substrate.

FIG. 32 is a diagram explaining a method for obtaining the flatness (ellipticity) when the projection image of the hole pattern is distorted into an oval shape.

FIG. 33 is a diagram explaining the tilt of the projection image of the elliptical hole pattern shown in FIG. 32.

FIG. 34 is a graph showing an example of a change characteristic of the refractive index of synthetic quartz as a function of wavelength.

FIG. 35 is a diagram schematically illustrating a state of image shift caused by a parallel flat plate-shaped quartz plate provided as an image shift optical member.

FIG. 36 is a graph showing an example of a difference caused by a relative position shift between a projection image formed by an i-ray and a projection image formed by an h-ray, which changes with the tilt angle of a quartz plate of an image shift optical member.

Claims (15)

An exposure device is used for projecting and exposing a pattern of a photomask to a light-sensitive substrate, and the device comprises: A light source for generating light including a plurality of bright-line wavelengths for illuminating the photomask; The first illumination optical system includes a wavelength selection unit that emits light from the light source and extracts an illumination light beam that includes at least one specific bright-line wavelength of the plurality of bright-line wavelengths to a predetermined wavelength width, and And a numerical aperture variable section that adjusts the divergence angle of the illumination beam; and A second illumination optical system includes an optical integrator, which is incident on the illumination beam whose divergence angle is adjusted to irradiate the illumination on the photomask with the same illuminance along with a numerical aperture corresponding to the divergence angle. Light beam; and The first wavelength selection element is installed in the wavelength selection unit, and while removing the bright line on the long wavelength side and the bright line on the short wavelength side appearing beside the specific bright line wavelength, the spectral components and The low-brightness spectral components distributed near the bottom of the specific bright line wavelength are extracted. The exposure apparatus according to claim 1, wherein The vicinity of the bottom where the low-brightness spectral component is distributed is set at the peak intensity of the spectral component with respect to the specific bright-line wavelength, and the relative intensity of the low-brightness spectral component averages several% or more, preferably 10% or more Range. The exposure device according to claim 2, wherein A mechanism for mounting a second wavelength selection element in a manner interchangeable with the first wavelength selection element is provided in the wavelength selection section, and the second wavelength selection element is distributed at the low-luminance near the bottom of the specific bright line wavelength. The peak-shaped spectral components other than the spectral components described above are extracted from the peak shape. The exposure device according to claim 3, wherein A third wavelength selection element is mounted on the wavelength selection section in an interchangeable manner, and includes a peak-shaped spectral component including at least one bright line wavelength appearing beside the specific bright line wavelength, and the specific bright line wavelength. The peak-like spectral components are extracted in both ways. An exposure method, which involves projecting and exposing a pattern of a photomask to a light-sensitive substrate, including: The wavelength selection is performed in such a manner that, together with a peak-like spectral component of at least one specific bright-line wavelength of light from a light source that generates light including a plurality of bright-line wavelengths, the above-mentioned specifics will not be included. The bright line on the long wavelength side and the bright line on the short wavelength side appearing next to the bright line wavelength, and the low-brightness spectral components distributed near the bottom of the specific bright line wavelength are extracted; and The illumination light beam with the spectral component selected by the wavelength is irradiated onto the mask with the same illuminance, and the specular projection method that does not produce color difference in the wavelength width including the spectral component of the low brightness is transmitted, or the spectrum of the low brightness is transmitted A projection optical system of a reflection-refraction method in which chromatic aberration is corrected in a component's wavelength width, and a pattern of the photomask is projected and exposed on the substrate. The exposure method as described in claim 5, wherein The vicinity of the bottom where the low-brightness spectral component is distributed is set at the peak intensity of the spectral component with respect to the specific bright-line wavelength, and the relative intensity of the low-brightness spectral component averages several% or more, preferably 10% or more Range. The exposure method as described in claim 6, wherein The light source is an ultrahigh-pressure mercury discharge lamp, and the specific bright-line wavelength is set to any one of i-ray, h-ray, and g-ray. An exposure method for irradiating light containing a bright line wavelength generated by a light source device with a spectral distribution of a specific bright line wavelength selected by a wavelength selection unit to an electronic component carrying light by an illumination optical system The patterned mask is used to project and expose the image of the pattern onto a light-sensitive substrate by using a projection optical system that projects the exposure light beam generated by the mask. Extracting the light of the first spectral distribution and the light of the second spectral distribution with different wavelength bands from the light generated by the light source device by the wavelength selecting section; and In order to use the illumination optical system to perform Kohler illumination on the photomask, a first light source image distributed in a two-dimensional range due to the light of the first spectral distribution on the pupil plane in the illumination optical system, and The second light source images distributed in the two-dimensional range due to the light of the second spectral distribution are superimposed. The exposure method as described in claim 8, wherein The two-dimensional range of the first light source image formed on the pupil surface is set in a circular area of a first radius from the center of the pupil surface, and the first area of the first light source image formed on the pupil surface is set. The two-dimensional range of the two-light source image is set in a circular area of a second radius from the center of the pupil surface. The exposure method as described in claim 9, wherein The first radius of the circular area forming the first light source image and the second radius of the circular area forming the second light source image may be adjusted to the same value or different values. The exposure method according to any one of claims 8 to 10, wherein The light source device includes a first mercury discharge lamp that generates the first spectrum distribution light extracted by the wavelength selection unit, and a second mercury discharge lamp that generates the second spectrum extracted by the wavelength selection unit. Light of distribution. The exposure method according to claim 11, wherein the first mercury discharge lamp and the second mercury discharge lamp are respectively ultra-high-pressure mercury discharge lamps whose mercury vapor pressure in the discharge tube is set to 10 ⁶ Pa (Pascal) or more. . The exposure method as described in claim 12, wherein An i-ray-broadband interference filter is provided in the above-mentioned wavelength selection section, which includes the spectral components of the i-rays from a plurality of bright-line wavelengths included in the light generated by the above-mentioned ultrahigh-pressure mercury discharge lamp, and includes In terms of the peak intensity of the spectral components of the i-rays, the spectral distribution in the vicinity of the bottom, which has an intensity of several% or more, preferably 10% or more, is extracted; Either the light of the first spectral distribution or the light of the second spectral distribution is extracted by the i-ray-broadband interference filter. The exposure method according to any one of claims 8 to 10, wherein The light source device includes: a mercury discharge lamp for obtaining the first spectrum distribution light extracted by the wavelength selection section; and a harmonic laser light source for obtaining the first light distribution extracted by the wavelength selection section. 2 Spectral distribution of light. An exposure method is to illuminate a mask pattern with illumination light having a predetermined wavelength distribution, and to project the imaging beam generated by the mask pattern into a projection optical system on a substrate to project the mask pattern. The image is projected and exposed on the substrate; it includes: The specific central wavelength in the wavelength distribution of the illumination light is set to λ, the numerical aperture on the substrate side of the projection optical system is set to NAp, and the program constant is set to k (0 <k ≦ 1).・ When the projected image of a square or rectangular hole pattern with the smallest resolvable minimum line width determined by the resolution R as defined by (λ / NAp) is projected on the substrate, the hole pattern is deformed into an oval shape. The width of the wavelength distribution of the illumination light including the central wavelength λ is set such that the ratio of the short-axis length to the long-axis length of the projected image becomes 80% or more, and preferably 90% or more; The mask having the pattern for electronic components formed is illuminated by the set illumination light having the above-mentioned wavelength distribution, and the pattern for electronic components is projected and exposed on the substrate.