JP2003021914A - Optical characteristic measuring method, optical characteristic measuring device, and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the optical characteristics of an optical system to be tested. SOLUTION: A mask RT on which a plurality of patterns having a width enabling the reduction of the effect of an asymmetrical aberration is formed is illuminated on an illumination condition suitable for reducing the effect of the asymmetrical aberration. The space images of the patterns and a plurality of measurement regions provided according to respective space images of the patterns are relatively moved, and at the same time, light quantities of light arriving at respective measurement regions are detected at respective positions in relative movement (Steps 112 to 115). Then, a waveform indicating the change of the light quantity of light arriving at a prescribed measurement region according to the change of a positional relationship between the space image and the prescribed measurement region is obtained on the basis of the measurement result, and the positional information of the space image is obtained on the basis of the obtained waveform (Step 116). The optical characteristics of the optical system to be tested is obtained on the basis of the positional information of the space image thus obtained (Step 117).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical characteristic measuring method, an optical characteristic measuring apparatus and an exposure apparatus, and more particularly to an optical characteristic measuring method and an optical characteristic measuring apparatus for measuring the optical characteristic of an optical system to be tested. The present invention also relates to an exposure apparatus including the optical characteristic measuring apparatus, an optical system whose optical characteristic is measured by the optical characteristic measuring method, and a semiconductor element manufactured using the exposure apparatus.

[0002]

2. Description of the Related Art Conventionally, in a lithography process for manufacturing a semiconductor device, a liquid crystal display device, etc., a pattern (hereinafter also referred to as a "reticle pattern") formed on a mask or a reticle (hereinafter collectively referred to as "mask"). A substrate such as a wafer or a glass plate coated with a resist or the like through a projection optical system (hereinafter collectively referred to as “substrate” as appropriate)
An exposure device that transfers images onto the top is used. As such an exposure apparatus, a static exposure type exposure apparatus such as a so-called stepper and a scanning exposure type exposure apparatus such as a so-called scanning stepper are mainly used.

In such an exposure apparatus, it is necessary to faithfully project the pattern formed on the reticle onto the substrate with high resolution. Therefore, the projection optical system is designed to have good optical characteristics in which various aberrations are sufficiently suppressed.

However, it is difficult to manufacture the projection optical system exactly as designed, and various aberrations due to various factors remain in the actually manufactured projection optical system.
Therefore, the optical characteristics of the projection optical system actually manufactured are
It will be different from the designed optical characteristics.

Particularly, in the projection optical system of the exposure apparatus, when distortion occurs, the shape of the fine processed pattern is distorted or the position is displaced, and it becomes difficult to transfer the fine pattern with high accuracy. For this reason, it is said that the distortion of the projection optical system needs to be suppressed to about several nm. In order to adjust and suppress such distortion aberration of the projection optical system, it is essential to measure the distortion aberration with high accuracy.

Conventionally, in measuring the distortion aberration,
The measurement pattern formed on the measurement mask is transferred to the substrate whose surface is coated with photoresist through the projection optical system that is the optical system to be measured, and the position information of the transferred pattern is used in a scanning electron microscope, etc. Was detected in. Then, the distortion of the projection optical system is measured based on the detected position information.

[0007]

In the above-mentioned conventional distortion aberration measuring technique, the substrate coated with the photoresist is exposed to transfer the measurement pattern. The position on the substrate depends on the thickness and optical characteristics of the applied photoresist.
For this reason, it has been difficult to consistently measure distortion aberration irrespective of the photoresist coating process and the type of photoresist.

Further, in order to observe the transferred measurement pattern with an observation device such as a scanning electron microscope,
It was usually necessary to develop the exposed substrate.
Therefore, in the conventional measurement of the distortion aberration, three steps of exposure (transfer of the measurement pattern), development, and observation are required, which requires a long measurement time.

Further, the position of the transferred pattern is not determined only by the distortion aberration that is inherent in the projection optical system and corresponds to the tilt of the wavefront, but higher-order asymmetric aberrations such as coma aberration of the projection optical system, illumination conditions, and pattern size. Etc. will be affected.
In order to evaluate the image distortion due to the projection optical system, it is necessary to evaluate the distortion aberration that is unique to the projection optical system and is not affected by the residual aberration. It had to be measured, and the distortion aberration peculiar to the projection optical system could not be accurately evaluated when assembling and adjusting the projection optical system.

The present invention has been made under the above circumstances, and a first object of the present invention is to measure the optical characteristics of the image forming optical system to be measured quickly and accurately. A method and an optical characteristic measuring device are provided.

A second object of the present invention is to provide an exposure apparatus capable of accurately transferring a predetermined pattern onto a substrate.

A third object of the present invention is to provide an optical system whose optical characteristics are accurately measured.

A fourth object of the present invention is to provide a semiconductor device having a fine pattern formed with high precision.

[0014]

The first optical characteristic measuring method of the present invention is an optical characteristic measuring method for measuring optical characteristics of an optical system under test (PL) having an imaging magnification β and a numerical aperture NA _O. A plurality of patterns (79X _k , 79) having a width V in a predetermined direction satisfying the condition of V> λ / (NA _O · β) and extending in a direction intersecting the predetermined direction.
_Yk ) illuminating a mask (RT) on which a mask (RT) is formed; aerial images (79X _k ') of the plurality of patterns by passing light that has passed through the plurality of patterns through the optical system under test. , 79Y _k ′); and a plurality of measurement regions (74X _k , 74) provided on the aerial image formation surface according to each of the plurality of patterns.
Y _k ) and the spatial image, while changing the positional relationship between the mask and the plurality of measurement regions so that the positional relationship changes between the mask and the plurality of measurement regions so as to change along the conjugate direction of the predetermined direction on the formation surface of the spatial image. A light detection step of simultaneously detecting the light amount of light reaching each of the plurality of measurement regions; and the light amount of light reaching each of the plurality of measurement regions due to a change in the positional relationship between the plurality of measurement regions and the aerial image. Based on the change
A position information calculating step of calculating position information about the conjugate direction for each aerial image of each of the plurality of patterns; and an optical characteristic calculating step of calculating optical characteristics of the optical system to be inspected using the calculated position information. And an optical characteristic measuring method including;

According to this, a plurality of patterns having a width V in a predetermined direction satisfying the condition of V> λ / (NA _O · β) and extending in a direction intersecting the predetermined direction are provided. Irradiate the mask on which is formed. Then, in the aerial image forming step, the aerial images of the plurality of patterns are formed by passing the light that has passed through the plurality of patterns through the optical system under test.
In the formation of such an aerial image, diffraction of light through the pattern formed on the mask is reduced, so that in the pupil plane,
An aerial image of the pattern is formed by light whose spread along the direction orthogonal to the traveling direction is reduced to some extent. As a result, it is possible to reduce the influence of asymmetrical aberration at the formation position of the aerial image.

Subsequently, in the photodetecting step, the positional relationship between the aerial image and the plurality of measurement regions provided on the aerial image forming surface corresponding to each of the plurality of patterns is in a conjugate direction of a predetermined direction on the aerial image forming surface. While changing the positional relationship between the mask and the plurality of measurement regions so as to change along the distance, the light amounts of the light reaching the plurality of measurement regions are simultaneously detected. As a result, information on the light intensity distribution in the conjugate direction regarding the aerial images of the plurality of patterns on the formation surface of the aerial images of the plurality of patterns formed by the optical system to be detected is detected all at once.

Then, in the position information calculating step, each aerial image of each of the plurality of patterns is based on the change of the light amount of the light reaching each of the plurality of measuring regions due to the change of the positional relationship between the plurality of measuring regions and the aerial image. After the position information regarding the conjugate direction is calculated in, in the optical characteristic calculation step,
The optical characteristics of the optical system to be tested are calculated using the calculated position information. Therefore, the influence of the asymmetrical aberration of the optical system to be measured can be reduced, and the optical characteristics such as the symmetrical aberration of the optical system to be measured can be measured accurately and quickly.

In the first optical characteristic measuring method of the present invention, in the illuminating step, the mask is irradiated with the light having the predetermined wavelength under an illumination condition in which the illumination coherence factor of the optical system to be tested is larger than 0.6. can do.

A second optical characteristic measuring method of the present invention is an optical characteristic measuring method for measuring an optical characteristic of a test optical system (PL), in which light having a predetermined wavelength is extended in a direction intersecting with a predetermined direction. An illuminating step of irradiating a mask (RT) on which a plurality of patterns (79X _k , 79Y _k ) are formed; light through the mask is made incident on the optical system to be inspected, and an aerial image (79X) of the plurality of patterns is formed. _k ', 79Y _k ') forming aerial image; a plurality of measurement regions (76X) provided on the aerial image forming surface according to each of the plurality of patterns.
_k , 76Y _k ) and the aerial image, the positional relationship between the mask and the plurality of measurement regions is changed so as to change along the conjugate direction of the predetermined direction on the formation surface of the aerial image. Meanwhile, a light detection step of relaying the light reaching the plurality of measurement areas by a relay optical system and detecting the light amount of the relayed light; and a change in the positional relationship between the plurality of measurement areas and the aerial image. A position information calculation step of calculating position information regarding the conjugate direction for each aerial image of each of the plurality of patterns based on a change in the amount of light reaching each of the plurality of measurement regions; using the calculated position information. And an optical characteristic calculating step of calculating the optical characteristic of the test optical system.

According to this, in the illuminating step, light having a predetermined wavelength is applied to a mask on which a plurality of patterns extending in a direction intersecting the predetermined direction are formed, and in the aerial image forming step, the light passing through the mask is radiated. It is made incident on the optical system to be inspected, and aerial images of a plurality of patterns are formed.

Subsequently, in the photodetecting step, the positional relationship between the aerial image and the plurality of measurement regions provided on the aerial image forming surface according to each of the plurality of patterns is determined by the conjugate direction of the predetermined direction on the aerial image forming surface. While changing the positional relationship between the mask and the plurality of measurement areas so as to change along, the light reaching the plurality of measurement areas is relayed by a relay optical system, and the light amount of the relayed light is detected. To do. As a result, in order to set the degree of coincidence with the formation surface of the aerial image, that is, the measurement area that requires high flatness, for example, an aperture plate or the like that can easily achieve high flatness can be used. Then, the light reaching the measurement region is relayed by the relay optical system, and by detecting the light amount of the relayed light, it is possible to accurately, in the formation surface of the aerial image of the plurality of patterns imaged by the optical system under test. Information about the light intensity distribution in the conjugate direction regarding the aerial image of each of the plurality of patterns is detected all at once.

Then, in the position information calculating step, based on the change in the light amount of the light reaching each of the plurality of measurement regions due to the change in the positional relationship between the plurality of measurement regions and the aerial image, After the position information regarding the conjugate direction is calculated for each aerial image, in the optical characteristic calculation step, the optical characteristic of the optical system under test is calculated using the calculated position information. Therefore, the optical characteristics of the test optical system can be measured accurately and quickly.

In the second optical characteristic measuring method of the present invention, when the imaging magnification of the optical system to be tested is β, the numerical aperture is NA ₀ , and the predetermined wavelength is λ, the predetermined direction of the pattern is The width V can satisfy the condition of V> λ / (NA _O · β).

Here, in the illuminating step, it is possible to illuminate the mask with the light of the predetermined wavelength under an illumination condition in which the illumination coherence factor of the optical system under test is larger than 0.6.

Further, according to the second optical characteristic measuring method of the present invention,
Is the numerical aperture of the optical system to be tested is NA _O, The relay optics
NA of the system_R, The predetermined wavelength is λ, the conjugate direction
When the width of the measurement area with respect to NA_R= Arbitrary (W ≤ 0.5 x λ / NA_O) NA_R≧ NA_OX 0.5 (0.5 x λ / NA_O≦ W ≦ 2 ×
λ / NA_O) NA_R≧ NA_O× 0.8 (W ≧ 2 × λ / NA_O) Satisfy any one of the three conditions
be able to.

In the second optical characteristic measuring method of the present invention,
Is the numerical aperture of the optical system to be tested is NA _O, The relay optics
NA of the system_R, The predetermined wavelength is λ, the optical test
Let σ be the illumination coherence factor of the system, and
When the width of the measurement area is set to W, NA_R= Arbitrary, σ = arbitrary (W ≦ 0.5 × λ / NA_O) NA_R≧ NA_O× 0.5, σ> 0.6 (0.5 × λ / NA_O≤W≤
2 x λ / NA_O) NA_R≧ NA_O× 0.8, σ> 0.6 (W ≧ 2 × λ / NA_O) Satisfy any one of the three conditions
be able to.

Here, the imaging magnification of the optical system to be tested is β,
When the width of the pattern in the predetermined direction is V, the condition of V> λ / (NA _O · β) can be further satisfied.

In the optical characteristic measuring method of the present invention, the width of the measurement area in the conjugate direction is set to be equal to or less than the width of the aerial image of the pattern in the conjugate direction, and the plurality of measurement areas are reached in the position calculating step. By obtaining the barycentric position for each waveform that reflects the change in the amount of light,
Position information can be calculated for each aerial image of each of the plurality of patterns.

Further, in the first and second optical characteristic measuring methods of the present invention (hereinafter, referred to as “optical characteristic measuring method of the present invention”), the width in the conjugate direction of the measurement region is defined as the aerial image of the pattern. Larger than the width in the conjugate direction,
In the position calculating step, the position information is calculated for each aerial image of each of the plurality of patterns by obtaining the barycentric position for each waveform that reflects the differential waveform of the light amount change of the light reaching each of the plurality of measurement regions. Can be

In the optical characteristic measuring method of the present invention, the optical characteristic can be distortion.

Here, an optical characteristic correction calculation step for correcting the distortion aberration of the optical system to be measured obtained in the optical characteristic calculation step based on previously measured asymmetrical aberration information of the optical system to be measured is further added. It can be included.

The first optical characteristic measuring apparatus of the present invention is an optical characteristic measuring apparatus for measuring an optical characteristic of the imaging magnification β and the target optical system of the numerical aperture NA _O (PL), of a predetermined wavelength λ The light has a plurality of patterns (79X _k , 79) each having a width V in a predetermined direction satisfying the condition of V> λ / (NA _O · β) and extending in a direction intersecting the predetermined direction.
An illumination system (10) for irradiating a mask (RT) on which Y _k ) is formed; and a plurality of the plurality of patterns formed by light passing through a plurality of patterns formed on the mask and passing through the optical system under test. Space image of pattern (79X _k ', 79
Y _k ′) on the formation surface, a plurality of measurement regions (74X _k , 7) provided in accordance with each of the plurality of patterns.
4Y _k ) and an optical measuring device (70) for simultaneously measuring the amount of light reaching each of them; and a positional relationship between the plurality of measurement regions and the aerial image in a conjugate direction of the predetermined direction on the formation surface of the aerial image. A drive device (24) for changing the positional relationship between the mask and the plurality of measurement areas so as to change along the plurality of measurement areas; A position information calculation device (32) that calculates position information regarding the conjugate direction for each aerial image of each of the plurality of patterns based on a change in the amount of light that has reached each of the measurement regions; An optical characteristic measuring device comprising: an optical characteristic calculating device (33) for calculating the optical characteristic of the optical system to be tested.

According to this, the illumination system has the width V in the predetermined direction satisfying the condition of V> λ / (NA _O · β) and allows the light of the predetermined wavelength λ to cross the predetermined direction. Irradiate a mask on which a plurality of extending patterns are formed. Subsequently, the drive device changes the positional relationship between the aerial image and the plurality of measurement regions provided on the aerial image forming surface according to each of the plurality of patterns along the conjugate direction of the predetermined direction on the aerial image forming surface. As described above, the photodetector simultaneously detects the light amounts of the light reaching the plurality of measurement regions while changing the positional relationship between the mask and the plurality of measurement regions.

Then, the position information calculating device calculates the amount of light reaching each of the plurality of measurement regions according to the change in the positional relationship between the plurality of measurement regions and the aerial image,
After calculating the position information regarding the conjugate direction for each aerial image of each of the plurality of patterns, the optical characteristic calculation device calculates the optical characteristic of the optical system to be tested using the calculated position information.

That is, the first optical characteristic measuring apparatus of the present invention can measure the optical characteristic of the optical system to be tested by using the first optical characteristic measuring method of the present invention. Therefore, the influence of the asymmetrical aberration of the optical system to be measured can be reduced, and the optical characteristics such as the symmetrical aberration of the optical system to be measured can be measured accurately and quickly.

In the first optical characteristic measuring apparatus of the present invention, the illumination system causes the light of the predetermined wavelength to be applied to the mask under an illumination condition in which the illumination coherence factor of the optical system under test is larger than 0.6. It can be configured to illuminate.

The second optical characteristic measuring apparatus of the present invention is an optical characteristic measuring apparatus for measuring the optical characteristic of the optical system to be measured (PL), and extends light of a predetermined wavelength in a direction intersecting the predetermined direction. An illumination system (10) for irradiating a mask (RT) having a plurality of patterns (79X _k , 79Y _k ) formed thereon; and the light formed through the plurality of patterns passing through the optical system under test. Aerial images of multiple patterns (79
X _k ′, 79Y _k ′), and a plurality of measurement regions (7) that are provided in accordance with the plurality of patterns, respectively.
6X _k , 76Y _k ) a light selection member (75) for selecting the light that has reached; a relay optical system (77) for relaying the light selected by the light selection member; a light relayed by the relay optical system A light detection device (78) for simultaneously detecting the light amount of each of the plurality of measurement regions; and the positional relationship between the plurality of measurement regions and the aerial image is along the conjugate direction of the predetermined direction on the formation surface of the aerial image. A drive device (24) for changing the positional relationship between the mask and the light selection member so that the measurement area changes with the positional relationship between the plurality of measurement areas and the aerial image of the pattern. A position information calculation device (32) for calculating position information regarding the conjugate direction for each aerial image of each of the plurality of patterns based on a change in the amount of light that has arrived; Te, the optical characteristic calculation unit (33) for calculating the optical characteristic of the optical system; an optical characteristic measuring device comprising a.

According to this, the illumination system irradiates the mask having the plurality of patterns extending in the direction intersecting the predetermined direction with the light of the predetermined wavelength. Subsequently, the drive device changes the positional relationship between the aerial image and the plurality of measurement regions provided on the aerial image forming surface according to each of the plurality of patterns along the conjugate direction of the predetermined direction on the aerial image forming surface. As described above, the positional relationship between the mask and the light selection member on which the plurality of measurement regions are formed is changed. Then, after the light selected by the light selection member is relayed by the relay optical system, the photodetector simultaneously measures the light amount of the light reaching each of the plurality of measurement regions.

Next, the position information calculation device determines each of the plurality of patterns based on the change in the light quantity of the light reaching each of the plurality of measurement regions due to the change in the positional relationship between the plurality of measurement regions and the aerial image. After calculating the position information regarding the conjugate direction for each aerial image of, the optical characteristic calculation device,
The optical characteristics of the test optical system are calculated using the calculated position information.

That is, the second optical characteristic measuring apparatus of the present invention can measure the optical characteristic of the optical system under test by using the second optical characteristic measuring method of the present invention. Therefore, the optical characteristics such as the symmetric aberration of the optical system to be measured can be measured accurately and quickly.

In the second optical characteristic measuring apparatus of the present invention, when the imaging magnification of the optical system to be tested is β, the numerical aperture is NA ₀ , and the predetermined wavelength is λ, the predetermined direction of the pattern is The width V can be configured to satisfy the condition of V> λ / (NA _O · β).

Here, the illumination system may be configured to irradiate the measurement mask with the light of the predetermined wavelength under an illumination condition in which the illumination coherence factor of the optical system to be tested is larger than 0.6. it can.

In the second optical characteristic measuring apparatus of the present invention,
Is the numerical aperture of the optical system to be tested is NA _O, The relay optics
NA of the system_R, The predetermined wavelength is λ, the conjugate direction
When the width of the measurement area with respect to NA_R= Arbitrary (W ≤ 0.5 x λ / NA_O) NA_R≧ NA_OX 0.5 (0.5 x λ / NA_O≦ W ≦ 2 ×
λ / NA_O) NA_R≧ NA_O× 0.8 (W ≧ 2 × λ / NA_O) A configuration that satisfies any of the three conditions represented by
be able to.

In the second optical characteristic measuring device of the present invention,
Is the numerical aperture of the optical system to be tested is NA _O, The relay optics
NA of the system_R, The predetermined wavelength is λ, the optical test
Let the illumination coherence factor of the system be σ,
The measurement area regarding the conjugate direction of the optical system under test
Let W be the width of NA_R= Arbitrary, σ = arbitrary (W ≦ 0.5 × λ / NA_O) NA_R≧ NA_O× 0.5, σ> 0.6 (0.5 × λ / NA_O≤W≤
2 x λ / NA_O) NA_R≧ NA_O× 0.8, σ> 0.6 (W ≧ 2 × λ / NA_O) A configuration that satisfies any of the three conditions represented by
be able to.

Here, the imaging magnification of the optical system to be tested is M,
When the width of the pattern in the predetermined direction is V, the condition of V> λ / (NA _O · M) can be further satisfied.

In the first and second optical characteristic measuring apparatus of the present invention (hereinafter referred to as "optical characteristic measuring apparatus of the present invention"), the optical characteristic can be distortion.

Here, an optical characteristic correction calculation device (34) for correcting the distortion aberration of the optical system to be measured, which is obtained by the optical characteristic calculating device, based on previously measured asymmetrical aberration information of the optical system to be measured. ) Can be further provided.

In the exposure apparatus of the present invention, the exposure light is exposed to the substrate (W
H) is an exposure device that transfers a predetermined pattern onto the substrate, and a projection optical system (PL) arranged on the optical path of the exposure light; And an optical characteristic measuring apparatus of the present invention as a system.

The optical system of the present invention is an optical system whose optical characteristics are measured by the optical characteristic measuring method of the present invention.

The optical system of the present invention is an optical system whose optical characteristics are measured by the optical characteristic measuring apparatus of the present invention.

The optical characteristic adjusting method of the present invention comprises an optical system (P
L) an optical characteristic adjusting method for adjusting the optical characteristic,
An optical characteristic measuring step of measuring an optical characteristic of the optical system using the optical characteristic measuring method of the present invention; an optical characteristic adjusting step of adjusting the optical characteristic of the optical system based on a measurement result in the optical characteristic measuring step. And a method for adjusting optical properties, which includes the steps of;

The semiconductor element of the present invention is a semiconductor element manufactured using the exposure apparatus of the present invention.

[0053]

BEST MODE FOR CARRYING OUT THE INVENTION << First Embodiment >> A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows the schematic arrangement of an exposure apparatus 100 according to the first embodiment of the present invention. The exposure apparatus 100 is a step-and-scan type projection exposure apparatus. The exposure apparatus 100 includes an illumination system 10, a reticle stage RST holding a reticle R, a projection optical system PL as a test optical system, a wafer stage WST on which a wafer WH as a substrate is mounted, and an alignment system A.
S, an optical measuring device 70 for measuring distortion aberration, a stage control system 19 for controlling the position and orientation of the reticle stage RST and wafer stage WST, a main control system 20 for overall control of the entire device, and the like.

The illumination system 10 includes a light source, an illuminance uniformizing optical system including a fly-eye lens, a relay lens, and a variable ND.
It is configured to include a filter, a reticle blind, a dichroic mirror, etc. (all not shown). The configuration of such an illumination system is disclosed, for example, in Japanese Patent Laid-Open No. 10-1124.
It is disclosed in Japanese Patent No. 33. In the illumination system 10, the slit-shaped illumination area portion defined by the reticle blind on the reticle R on which a circuit pattern or the like is drawn is illuminated by the illumination light I.
Illuminate with a substantially uniform illuminance. The main control system 2
According to the illumination control instruction data LCD from 0, the illumination conditions such as the illumination coherence factor (hereinafter referred to as “illumination σ”) by the illumination system 10 can be changed.

The reticle R is fixed on the reticle stage RST by, for example, vacuum suction. The reticle stage RST has an optical axis of the illumination system 10 (which coincides with an optical axis AX of a projection optical system PL described later) for positioning the reticle R by a reticle stage driving unit (not shown) including a two-dimensional linear actuator. It can be finely driven in the XY plane perpendicular to the X axis and can be driven at a scanning speed designated in a predetermined scanning direction (here, the Y direction). Further, in the present embodiment, the above 2
Since the dimensional linear actuator also includes a Z driving actuator, it can be minutely driven in the Z direction.

The position of the reticle stage RST on the stage moving surface is constantly detected by a reticle laser interferometer (hereinafter referred to as "reticle interferometer") 16 via a moving mirror 15 with a resolution of, for example, about 0.5 to 1 nm. To be done. The position information (or speed information) RPV of the reticle stage RST from the reticle interferometer 16 is sent to the main control system 20 via the stage control system 19, and the main control system 20 outputs this position information (or speed information) RPV. Based on this, the reticle stage RST is driven via the stage control system 19 and the reticle stage drive section (not shown).

The projection optical system PL is arranged below the reticle stage RST in FIG. 1, and its optical axis AX is in the Z-axis direction. The projection optical system PL is, for example, a both-side telecentric reduction system, and is composed of a plurality of lens elements (not shown) having a common optical axis AX in the Z-axis direction. In addition, this projection optical system P
As L, the projection magnification β is, for example, 1/4, 1/5, 1 /
Something like 6 is used. Therefore, as described above, when the illumination area on the reticle R is illuminated by the illumination light (exposure light) IL, the pattern formed on the reticle R is reduced by the projection optical system PL at the projection magnification β. The image (partially inverted image) is projected and transferred onto a slit-shaped exposure area on the wafer WH having a surface coated with a resist (photosensitive agent).

In the present embodiment, among the plurality of lens elements described above, specific lens elements (for example, five predetermined lens elements) can be independently moved. Such movement of the lens element is performed by driving elements such as three piezo elements provided for each specific lens, which support a lens supporting member that supports the specific lens element and are connected to the lens barrel portion. There is. That is, the specific lens elements can be independently moved in parallel along the optical axis AX according to the displacement amount of each drive element, or a desired inclination can be given to a plane perpendicular to the optical axis AX. You can also do it. Then, the drive instruction signals provided to these drive elements are controlled by the imaging characteristic correction controller 65 to which the instruction MCD from the main control system 20 is supplied,
With this, the displacement amount of each drive element is controlled.

In the projection optical system PL thus constructed,
By controlling the movement of the lens element via the imaging characteristic correction controller 65 by the main control system 20, optical characteristics such as distortion, field curvature, astigmatism, coma, or spherical aberration can be adjusted.

The wafer stage WST is arranged on a base (not shown) below the projection optical system PL in FIG. 1, and the wafer holder 2 is placed on the wafer stage WST.
5 is placed. The wafer WH is fixed on the wafer holder 25 by, for example, vacuum suction. The wafer holder 25 is driven by a drive unit (not shown) to project the projection optical system PL.
With respect to the plane orthogonal to the optical axis, the optical axis can be tilted in any direction and can be finely moved in the optical axis AX direction (Z direction) of the projection optical system PL. The wafer holder 25 has an optical axis AX.
It is also possible to rotate around.

The wafer stage WST is not only moved in the scanning direction (Y direction), but is also perpendicular to the scanning direction so that a plurality of shot areas on the wafer WH can be positioned in an exposure area conjugate with the illumination area. Direction (X direction), the operation of scanning and exposing each shot area on the wafer WH and the operation of moving to the exposure start position of the next shot are repeated. Perform scan operation. This wafer stage W
The ST is driven in the XY two-dimensional directions by a wafer stage drive unit 24 as a drive device including a motor and the like.

The position of wafer stage WST in the XY plane is adjusted by a wafer laser interferometer (hereinafter referred to as "wafer interferometer") 18 via a movable mirror 17 to, for example, 0.5.
It is constantly detected with a resolution of about 1 nm. The position information (or speed information) WPV of wafer stage WST is sent to main control system 20 via stage control system 19, and main control system 20 is based on this position information (or speed information) WPV and stage control system 19 And wafer stage drive unit 24
Drive control of wafer stage WST is performed via.

The alignment system AS is a projection optical system P.
In the present embodiment, an off-axis type microscope including an image forming alignment sensor for observing the street lines and the position detection marks (fine alignment marks), which are arranged on the side surface of L, is used in this embodiment. There is. The detailed configuration of this alignment system AS is disclosed in, for example, Japanese Patent Laid-Open No. 9-219354. The observation result by the alignment system AS is supplied to the main control system 20.

Further, in the apparatus of FIG. 1, the oblique incidence type focus detection system (focus detection) for detecting the position in the Z direction (optical axis AX direction) inside the exposure area on the surface of the wafer WH and in the vicinity thereof. A multi-point focus position detection system (21, 22), which is one of the systems), is provided. The multi-point focus position detection system (21, 22) is an irradiation optical system 21 including an optical fiber bundle, a condenser lens, a pattern forming plate, a lens, a mirror, and an irradiation objective lens (all not shown).
And a light receiving optical system 22 including a condenser objective lens, a rotation direction vibrating plate, an image forming lens, a light receiving slit plate, and a light receiver (not shown) having a large number of photosensors. This multi-point focus position detection system (21,
22), for details of the configuration, refer to, for example, Japanese Patent Laid-Open No. 6-2
It is disclosed in Japanese Patent No. 83403. The detection result of the multipoint focus position detection system (21, 22) is supplied to the stage control system 19.

As shown in FIG. 2, the optical measuring device 70 has a mounting table 71 provided on the wafer stage WST.
And an upper surface (a light receiving surface to be described later) of the image forming surface of the pattern formed on the reticle R by the projection optical system PL (hereinafter, simply referred to as “image surface”). The photodetector 72 is set to the Z position.

As shown in FIG. 3, the photo-detecting section 72 has a rectangular light receiving surface 74X _k (k = 1, 2, ..., K) as a measurement region whose longitudinal direction is the Y-axis direction. a photodetector 73X _k, also the light detector pair 73 _k consisting of a photodetector 73Y _k having a rectangular light receiving surface 74Y _k to the X-axis direction to the longitudinal direction of the measurement region, X-direction pitch P
They are arranged in a matrix with a pitch PT in the T and Y directions. Here, the light-receiving surface 74X _k has a rectangular shape having an X-direction width W and a Y-direction width LM (> W), and the light-receiving surface 74Y _k has an X-direction width LM and a Y-direction width W. It has a rectangular shape. The arrangement of the photodetector pairs is not limited to the matrix, and other arrangements may be used. Further, in FIG. 3, an example of K = 25 is shown, but it goes without saying that another value can be adopted as the value of K.

The light-receiving surfaces 74X _k and 74Y _k are in the same Z position in parallel with the image plane. Light-receiving surface 74X _k ,
The amount of light reaching each of the 74Y _k is determined by the photodetector 73.
It is detected by X _k , 73Y _k , and the detection result is supplied to the main control system 20 as detection result data IMD1.

As shown in FIG. 4, the main control system 20 comprises a main control device 30 and a storage device 40.

The main control unit 30 includes (a) reticle R
Based on the position information (speed information) RPV of the wafer and the position information (speed information) WPV of the wafer WH.
A control device 39 for controlling the overall operation of the exposure apparatus 100 by supplying the stage control data SCD to, and (b) a data collecting device 31 for collecting the light detection result data supplied from the light measuring device 70. c) a position information calculation device 32 that calculates position information of a measurement pattern described later based on the data collected by the data collection device 31,
(D) An optical characteristic calculation device 33 that calculates a first-order distortion aberration measurement value of the projection optical system PL based on the position information calculated by the position information calculation device 32. Further, main controller 30 corrects the first-order distortion aberration measurement value by using (e) pre-measured asymmetrical aberration information of projection optical system PL to calculate the second-order distortion aberration measurement value. The arithmetic unit 34 is further provided.

The storage device 40 includes a collected data storage area 41, a position information storage area 42, and a primary measurement value storage area 4
3, an asymmetric aberration information storage area 44, and a secondary measurement value storage area 45.

In FIG. 3, the data flow is shown by solid arrows and the control flow is shown by dotted arrows. The operation of each device of main controller 30 will be described later.

In the present embodiment, the main control device 30 is configured by combining various devices as described above, but the main control system 20 is configured as a computer system and the main control device 30 is configured.
The functions of the above-mentioned respective devices constituting the
It is also possible to realize it by a program built in.

The exposure operation of the exposure apparatus 100 of this embodiment will be described below with reference to the flow chart shown in FIG.
Description will be given with reference to other drawings as appropriate.

As the premise of the following operation, the asymmetrical aberration W _n (n: the order of the asymmetrical aberration) of each order of the projection optical system PL and the asymmetrical aberration W _n are the measurement results of the distortion aberration of the projection optical system PL. It is assumed that the coefficient A _n that represents the influence on is already obtained and is stored in the asymmetric aberration information storage area 44. That is, if the first-order measurement value D1 of the distortion aberration of the projection optical system PL is obtained, it is assumed that preparations for calculating the true distortion aberration D0 by the following equation (1) are completed.

[0076]

[Equation 1]

In the process shown in FIG. 5, first, in the subroutine 101, the distortion aberration of the projection optical system PL is measured. In this distortion measurement, as shown in FIG. 6, first, in step 111, the reticle loader (not shown) loads the measurement reticle RT for distortion aberration measurement shown in FIG. 7 onto the reticle stage RST. At the same time, the illumination σ is set. Reticle R for measurement
As shown in FIG. 7, T has a rectangular opening pattern 79X _k (k = 1, 2, ..., T) whose longitudinal direction is in the Y-axis direction.
K) and a rectangular opening pattern 79Y _k having a longitudinal direction in the X-axis direction, the opening pattern pairs 79 _k are arranged in a matrix with an X-direction pitch (PT / β) and a Y-direction pitch (PT / β). It is arranged. Here, the opening pattern 79
X _k has a rectangular shape having an X-direction width V and a Y-direction width L (> V), and the opening pattern 79Y _k has a rectangular shape having an X-direction width L and a Y-direction width V. There is. In the present embodiment, when measuring the distortion of the projection optical system PL, the X position information of the aerial image of the aperture pattern 79X _k formed by the projection optical system PL is detected, and
Aperture pattern 79Y formed by the projection optical system PL
The Y position information of the aerial image of _k is detected.

That is, in the present embodiment, the above-mentioned photodetector pairs 7 are arranged so as to correspond to the respective aperture pattern pairs 79 _k .
_3k are arranged. The width V in the X direction of the opening pattern 79X _k forming the pair of opening patterns 79 _k (the width V in the Y direction of the opening pattern 79Y _k ) and the width in the X direction of the photodetector 73X _k forming the photodetector pair 73 _k. W (Y of photodetector 73Y _k
The relationship expressed by the following equation (2) is established with respect to the direction width W).

[0079]       W ≦ β · V (2)

Here, the setting of the width V of the opening pattern 79X _{k in} the X direction (the width V of the opening pattern 79Y _{k in} the Y direction) will be described.

First, as shown in FIG. 8A, the X-position of the aerial image of this pattern by the projection optical system PL is used by using the measurement reticle RTA on which a pattern having a very narrow width in the X-direction is formed. Consider measuring. Here, it is assumed that the distortion of the projection optical system PL is 0 and only coma is present.

In this case, when the measurement reticle RTA is irradiated with the illumination light IL, the light passing through the pattern having a very narrow width in the X direction spreads greatly in the ± X directions due to diffraction. As a result, the light transmitted through the measurement reticle RTA is reflected on the pupil plane PL.
It will pass through the entire surface of P. As described above, since the distortion of the projection optical system PL is 0 and it is assumed that only coma is present, the wavefront W on the pupil plane PLP is assumed.
F becomes as shown in FIG. Note that FIG.
In (A), the wavefront WF shows coma aberration by Zernik.
This is represented by the wavefront aberration of e.

Generally, the positional deviation of the pattern image formed by the projection optical system PL indicates the inclination of the wavefront aberration as the pupil plane PL.
It is proportional to the result of integration over the region where the light flux at P is transmitted. Therefore, in the case of a pattern having a very narrow width in the X direction as shown in FIG. 8A, the positional deviation of the pattern image in the X direction causes the inclination of the wavefront WF over the entire range of the pupil plane PLP in the X direction. It will be proportional to the result of integration. However, this integration result is not 0,
It will have a finite value.

This indicates that even if the projection optical system PL does not have distortion, the coma aberration causes the image position to shift. That is, if a pattern with a very narrow width is used and the distortion aberration of the projection optical system PL is to be measured based on the positional shift of the pattern image, an error due to the contribution of coma aberration is inevitably accompanied. Therefore, in order to accurately measure the distortion aberration of the projection optical system PL based on the positional deviation of the pattern image, it is necessary to make asymmetric aberrations other than the distortion aberration such as coma aberration zero, but in reality, , It is impossible to completely eliminate these asymmetrical aberrations.

Next, as shown in FIG. 8B, a measurement reticle RTB having a pattern having a wide width in the X direction is formed.
Consider using X to measure the X position of the aerial image of this pattern by the projection optical system PL. Again, FIG.
As in the case of (A), the distortion of the projection optical system PL is 0.
It is assumed that there is only coma.

In this case, when the measurement reticle RTB is irradiated with the illumination light IL, the light passing through the pattern having a wide width in the X direction is not much affected by diffraction. As a result, the light transmitted through the measurement reticle RTB will pass through a specific region of the pupil plane PLP. The size of this particular area is
Generally, it is determined by the value of illumination σ.

Also in the case of FIG. 8B, since it is assumed that the distortion of the projection optical system PL is 0 and only coma is present, the wavefront WF at the pupil plane PLP is as shown in FIG.
As shown in FIG. 8B, it becomes the same as in the case of FIG.

Therefore, in the case of a pattern having a wide width in the X direction as shown in FIG. 8B, the positional deviation of the pattern image in the X direction is caused by the inclination of the wavefront WF over the entire specific area of the pupil plane PLP. However, by adjusting the value of the illumination σ and adjusting the size of the specific region through which the light flux passes on the pupil plane PLP, the integration result becomes 0 or becomes very small. can do.

That is, when the distortion aberration of the projection optical system PL is measured from the positional deviation of the aperture pattern formed on the measurement reticle by the projection optical system PL in the predetermined direction, the aperture pattern of the measurement reticle is measured. It is preferable that the width of the aperture pattern in the conjugate direction with respect to the direction in which the spatial image positional deviation is measured is made wide so that the transmitted light of the aperture pattern is not significantly affected by diffraction.

[0090] From this viewpoint, the present inventors have opening patterns 79X _k, while changing the width of 79Y _k V (see FIG. 7), the positional deviation of the opening pattern images (positional deviation of the center position of the aperture pattern image) When the projection optical system PL has each of the third-order coma aberration and the fifth-order coma aberration that are highly likely to contribute significantly, the positional deviation of the aperture pattern image causes the illumination σ.
We calculated by simulation how it changes with the change. The wavelength of the illumination light λ = 248 nm,
Numerical aperture NA ₀ = 0.75 of projection optical system PL, magnitude of third-order coma aberration = 0.01λrms, magnitude of fifth-order coma aberration = 0.01λrms, and imaging magnification β of projection optical system PL
= 1/4, and a simulation was performed. The results of this simulation are shown in FIGS. 9 (A) and 9 (B). Here, FIG. 9A shows a simulation result when the projection optical system PL has a third-order coma aberration, and FIG. 9B shows a case where the projection optical system PL has a fifth-order coma aberration. The simulation result of is shown.

As shown in FIG. 9A, when the pattern width V is about 0.8 μm or more, the positional deviation due to the third-order coma aberration can be made zero by adjusting the value of the illumination σ. it can. Further, as shown in FIG. 9B, when the pattern width V is about 2.0 μm or more, the positional deviation due to the fifth-order coma aberration can be made zero by adjusting the value of the illumination σ. . As a result, the pattern width V is 2.
It can be seen that if the value is about 0 μm or more, the third-order and fifth-order coma aberrations may be set to 0 by adjusting the value of the illumination σ.

The present inventor investigated the range of the pattern width V in which the third and fifth coma aberrations may be set to 0 by setting a small step of the change of the pattern width V, and further, The range of the pattern width V that can reduce the positional deviation due to other asymmetrical aberrations was examined.
As a result, when the pattern width V satisfies the condition of V> λ / (NA ₀ · β) (3), it is possible to reduce the positional deviation of the aperture pattern image due to asymmetrical aberrations other than the distortion aberration. It was found.

Reflecting this result, in this embodiment, the width V of the opening patterns 79X _k and 79Y _k is set to a value satisfying the condition of the expression (3).

Next, the setting of the illumination σ at the time of measuring the distortion aberration will be described. In general, the positional deviation of the aperture pattern image due to each of a plurality of asymmetrical aberrations other than the distortion aberration cannot be zero at the same time. For this reason, it is desirable that the illumination σ during the measurement of the distortion aberration be set to a value within a range in which the positional deviation of the aperture pattern image can be simultaneously reduced to a certain degree or less for any of the plurality of asymmetrical aberrations other than the distortion aberration. Therefore, the inventor of the present invention uses the above simulation results to calculate the change in the positional deviation of the aperture pattern image due to the change in the illumination σ for each type of asymmetrical aberration as described in (3) above.
Each value of the pattern width V satisfying the formula was investigated. A representative result of this investigation result is shown in FIG. That is, in FIG. 10, when the pattern width V = ∞, the magnitude of the third-order coma aberration = 0.01λrms, the magnitude of the fifth-order coma aberration = 0.01λrms, and the magnitude of the seventh-order coma aberration =
A change in the positional deviation of the aperture pattern image due to a change in illumination σ is shown when 0.01λrms is present.

Illumination σ, as typically shown in FIG.
If the value of is larger than 0.6, the positional deviation of the aperture pattern image due to each asymmetrical aberration can be suppressed. Therefore, in the present embodiment, the setting is made so that the condition of σ> 0.6 (4) is satisfied when measuring the distortion aberration. The setting of the illumination σ is performed by the main control system 20 supplying the illumination control instruction data LCD to the illumination system 10.

Returning to FIG. 6, next, at step 112, the wafer stage WST is moved to the initial position (hereinafter referred to as “X initial position”) for position measurement of the aerial image 79X _k ′ (see FIG. 11) of the pattern 79X _k in the X direction. Position)). When wafer stage WST moves to the X initial position, the upper surface of photodetector 72, that is, pattern 79X _k ,
In forming surface of the spatial image of 79Y _k, the light-receiving surface 74X _k as shown in FIG. 11, and 74Y _k, pattern 79X _k,
The spatial relationship between 79Y _{k and} the aerial images 79X _k ′ and 79Y _k ′ is obtained. That is, the light receiving surfaces 74X _k and 74Y _k and the aerial image 7
9X _k ', 79Y _k' and is 'while located outside in the -X direction, the entire light-receiving surface 74Y _k space image 79Y _k' entire light receiving surface 74X _k space image 79X _k located outside in the + Y direction It is considered as a positional relationship. Even if the light-receiving surface 74X _k moves in the + X direction, the light-receiving surface 74Y _k
There spatial image 79X _k 'with no intersection with, even the light-receiving surface 74Y _k moves in the -Y direction, the light-receiving surface 74X _k space image 79Y _k' is that there is no positional relationship that intersects the .

The movement of the wafer stage WST is performed by the main control system 20 based on the position information (speed information) of the wafer stage WST detected by the wafer interferometer 18 via the stage control system 19 and the wafer stage drive unit 24. Control is performed. At this time, the main control system 20, based on the detection result of the multi-point focus position detection system (21, 22), the upper surface of the light detection unit 72, that is, the light receiving surface 74X _k ,
The 74Y _k, spatial image 79X _k ', 79Y _k' to match the forming surface of minutely driving the wafer stage WST in the Z-axis direction via wafer stage drive section 24.

Subsequently, the main control system 20 supplies the illumination control instruction data LCD to the illumination system 10, and causes the reticle R to be illuminated under the illumination condition satisfying the condition of the expression (4).

Returning to FIG. 6, in step 113, the main control system 20 controls the wafer stage drive unit 24 via the stage control system 19 to move the wafer stage WST from the X initial position in the + X direction. Let That is, the light receiving surface 74X _k passes from a position where the light receiving surface 74X _k partially overlaps with the corresponding spatial image 79X _k ′ shown in FIG. 12B from the initial position shown in FIG. 12A. After that, the light receiving surface 74X _k shown in FIG.
Wafer stage WST, and thus optical measuring device 70, is moved to a position where all of the above are outside in the + X direction of corresponding aerial image 79X _k ′. Then, during the movement of the wafer stage WST, the light receiving surface 74 at each movement position (for example, each movement position of 1/1024 of the total movement distance).
The light amount of the light reaching X _k is detected by the photodetector 73X _k , and the detection result at each moving position is detected by the light detection data IMD.
1 is supplied to the main control system 20.

In the main control system 20, the main control device 30 described above is used.
The data collection device 31 collects the photodetection data IMD1 for each moving position and stores it in the collection data storage area 41 together with the position information SPD of the wafer stage WST supplied from the main controller 30. And the main control system 20
Indicates that the main control system 20 sends the illumination control instruction data L to the illumination system 10.
The CD is supplied and the illumination on the reticle R is terminated.

Returning to FIG. 6, next, at step 114, main control system 20 sets wafer stage WST to pattern 7.
It moves to the initial position (hereinafter referred to as “Y initial position”) for position measurement in the Y direction of the aerial image 79Y _k ′ (see FIG. 11) of 9Y _k . In the present embodiment, the Y initial position of wafer stage WST coincides with the X initial position described above.

Subsequently, the main control system 20 supplies the illumination control instruction data LCD to the illumination system 10, and causes the reticle R to be illuminated under the illumination condition satisfying the condition of the expression (4).

Then, in step 115, main control system 20 controls wafer stage drive unit 24 via stage control system 19 to move wafer stage WST from the Y initial position to the -Y direction. That is, the light receiving surface 74Y _k passes from a position where the light receiving surface 74Y _k partially overlaps with the corresponding aerial image 79Y _k ′ shown in FIG. 13B from the initial position shown in FIG. 13A. After doing
Wafer stage WST is moved to the position shown in FIG. 13C _where all of light-receiving surfaces 74Y _k are outside the corresponding aerial image 79Y _k ′ in the −Y direction. Then, during the movement of the wafer stage WST, the light amount of the light reaching the light receiving surface 74Y _k at each movement position is detected by the photodetector 73.
It is detected by Y _k , and the detection result at each moving position is supplied to the main control system 20 as light detection data IMD1.

In the main control system 20, the main control device 30 described above is used.
The data collection device 31 collects the photodetection data IMD1 for each moving position and stores it in the collection data storage area 41 together with the position information SPD of the wafer stage WST supplied from the main controller 30. And the main control system 20
Indicates that the main control system 20 sends the illumination control instruction data L to the illumination system 10.
The CD is supplied and the illumination on the reticle R is terminated.

[0105] Returning to FIG. 6, then, in step 116, the position information calculating unit 32, based on the collected data, for X-position X _k and the measurement of the aerial image 79X _k 'of the measurement aperture pattern 79X _k Aerial image 79 of aperture pattern 79Y _k
The Y position Y _k of Y _k 'is calculated. In the calculation of the position information, the position information calculation device 32 first reads the result of the moving light amount measurement regarding the aerial image 79X _k ′ and the position information of the light detection position from the collected data storage area 41, and calculates the position of the light detection data. The change waveform corresponding to the change in the moving position is obtained. When the waveform IX _k (X) obtained by summing the light beams derived from the aerial image 79X _k ′ in the Y-axis direction is the one shown in FIG.
The waveform is JX _k (X) shown in (B). This waveform J
X _k (X) has a shape in which the above waveform IX _k (X) is spread, but the center of gravity of the waveform JX _k (X) is the waveform I
It almost coincides with the position of the center of gravity of X _k (X). Here, as is well known, the center of gravity position of the waveform IX _k (X) is the center X position of the aerial image 79X _k ′, that is, the aerial image 7
Since the estimated value for the X position of 9X _k 'is highly accurate, the position information calculation device 36 determines that the waveform JX
By calculating the barycentric position of _k (X), the aerial image 79
The X position X _k of X _k 'is calculated. Then, the calculated X position X _k is stored in the position information storage area 42.

As shown in FIG. 14A, in addition to the signal peak PK1, a peak (hereinafter referred to as "noise peak") PK2 derived from residual coma aberration in the projection optical system PL has a waveform IX _k (X). In the above case, the measured waveform JX _k (X) also has a noise peak PK2 ′ in addition to the signal peak PK1 ′. Therefore, in the calculation of the center of gravity of the waveform JX _k (X), the influence of noise is directly reflected on the calculated X position of the aerial image 79X _k ′.

Therefore, as shown in FIG.
{JX _k (X)} ^P (P> 1: P = 2 in FIG. 14C)
Is obtained, it is possible to relatively reduce the height of the noise peak PK2 ″ with respect to the signal peak PK1 ″. Therefore, the center of gravity is calculated for the waveform {JX _k (X)} ^P , and
By calculating the X position of the aerial image 79X _k ′, the center of gravity of the waveform JX _k (X) is calculated to reduce the influence of noise more than when the X position of the aerial image 79X _k ′ is calculated.
The X position can be calculated accurately. Note that JX _k
The noise superposition in (X) is due to the noise peak PK2 ′.
The noise is not limited to the vicinity, and the noise may not have a peak. However, in the waveform {JX _k (X)} ^P , the contribution of noise to the waveform is more reliable than in the case of the waveform JX _k (X). Since it is reduced, the waveform {JX
By calculating the center of gravity of _k (X)} ^P , the accuracy of the X position of the calculated aerial image 79X _k ′ can be improved.

Further, as shown in FIG. 15, the waveform JX
_{At k} (X), a threshold value J _TH larger than the peak value of the noise peak PK2 ′ is set, and the center of gravity of a region having a larger value than the threshold value J _TH is calculated to calculate the center of gravity of the waveform JX _k (X). Thus, the influence of noise can be reduced and the X position can be calculated more accurately than when the X position of the aerial image 79X _k 'is calculated. For example, when the residual coma aberration is 0.05λrms, the threshold value J _TH may be set to about 20% of the signal peak value.

In step 116 of FIG. 6, the above
Aerial image 79X_k’X position X_kFollowing the calculation of
The information calculation device 32 displays the space from the collected data storage area 41.
Image 79Y_kOf the moving light amount measurement for
Position information and the position of movement of the light detection data
The change waveform corresponding to the change is obtained. And X position X _k
In the same way as for the calculation of
By detecting the aerial image 79Y_k’Y position Y_kTo
calculate. Then, the calculated Y position Y_kLocation information
The data is stored in the storage area 42.

Next, in step 117, the optical characteristic calculation device 33 reads the position information (X _k , Y _k ) from the position information storage area 42 and calculates the first-order distortion D of the projection optical system PL. . The calculation of the first-order distortion aberration D is performed by calculating the mutual positional relationship of the X position X _{k and} the mutual positional relationship of the Y position Y _k that are expected when there is no distortion, and the mutual positional relationship of the measured X position X _k. And the Y position Y _k is different from the mutual positional relationship, and is calculated by a known method. The optical characteristic calculation device 33 stores the first-order distortion aberration D thus calculated in the first-order measured value storage area 43.

Subsequently, the optical characteristic correction arithmetic unit 34
The first-order distortion D is read out from the first-order measured value storage area 43, and the asymmetrical aberration information storage area 44 described above is read.
The asymmetrical aberration W _n of each order of the projection optical system PL (n: the order of the asymmetrical aberration) and the coefficient A _n representing the influence of each asymmetrical aberration W _n on the measurement result of the distortion aberration of the projection optical system PL are read from. . Then, according to the equation (1) described above,
The first-order distortion aberration D is corrected to calculate the second-order distortion aberration, that is, the true distortion aberration D0. Optical characteristic correction arithmetic unit 3
Reference numeral 4 designates the second-order distortion aberration D0 calculated in this manner as the finally-measured distortion aberration, and the second-order measurement value storage area 4
Store in 4.

When the measurement of the distortion aberration of the projection optical system PL is completed in this way, the processing shifts to step 102 in FIG.

In step 102, the main control system 20 reads out the distortion aberration D0 measured from the secondary measurement value storage area 44, and whether or not the measurement result of the distortion aberration of the projection optical system PL is less than or equal to the allowable value. To judge. If this determination is affirmative, the process proceeds to step 104. on the other hand,
If the determination is negative, the process moves to step 103. At this stage, the following description will be made assuming that the determination is negative and the process has proceeded to step 103.

At step 103, the main control system 20 reduces the currently generated distortion based on the measurement result of the distortion of the projection optical system PL.
Adjustment. For such adjustment, the control device 39 controls the movement of the lens element via the imaging characteristic correction controller 65, and in some cases, the movement of the lens element of the projection optical system PL in the XY plane or the lens is manually performed. This is done by replacing the element.

Continuing, in subroutine 101,
The distortion aberration of the adjusted projection optical system PL is measured in the same manner as above. After that, the adjustment of the distortion aberration of the projection optical system PL (step 103) and the measurement of the distortion aberration (step 101) are repeated until a positive determination is made in step 102. Then, if an affirmative determination is made in step 102, the process proceeds to step 10
Go to 4.

In step 104, under the control of the main control system 20, after the measurement reticle RT is unloaded from the reticle stage RST by the reticle unloader (not shown), the pattern to be transferred is transferred by the reticle loader (not shown). The formed reticle R is the reticle stage R
Loaded to ST. The wafer WH to be exposed is loaded on the wafer stage WST by a wafer loader (not shown).

Next, in step 105, exposure preparation measurement is performed under the control of the main control system 20. That is, preparation work such as reticle alignment using a reference mark plate (not shown) arranged on wafer stage WST and measurement of the baseline amount of alignment system AS are performed. In addition, when the exposure of the wafer WH is the exposure of the second layer and thereafter, in order to form the circuit pattern with a high overlay accuracy with the already formed circuit pattern, the above-mentioned EGA measurement using the alignment system AS is performed to measure the wafer. The array coordinates of the shot areas on the WH are detected with high accuracy.

Next, in step 106, exposure is performed. In this exposure operation, first, the wafer WH
Wafer stage WST is moved so that the XY position of is the scanning start position for the exposure (first shot) of the first shot area on wafer WH. Position information (velocity information) and the like from the wafer interferometer 18 (in the case of exposure of the second and subsequent layers, the detection result of the positional relationship between the reference coordinate system and the array coordinate system, the position information from the wafer interferometer 18 ( (Speed information) and the like) by the main control system 20 via the stage control system 19 and the wafer stage drive unit 24. At the same time, the reticle stage RST is moved so that the XY position of the reticle R becomes the scanning start position.
This movement is performed by the main control system 20 via the stage control system 19 and a reticle drive unit (not shown).

Next, the stage control system 19 operates the main control system 2
In response to an instruction from 0, the multi-point focus position detection system (2
Wafer position information detected by reticle R, XY of reticle R measured by reticle interferometer 16
Based on the position information and the XY position information of the wafer WH measured by the wafer interferometer 18, the reticle R and the reticle R are adjusted while adjusting the surface position of the wafer WH via a reticle drive unit and a wafer stage drive unit 24 (not shown). Scan exposure is performed by relatively moving the wafer WH.

Thus, when the exposure of the first shot area is completed, the wafer stage WST is moved to the scanning start position for the exposure of the next shot area and the XY position of the reticle R is scanned. Reticle stage RST is moved to the position. Then, scanning exposure for the shot area is performed in the same manner as the above-described first shot area. Thereafter, scanning exposure is similarly performed for each shot area, and the exposure is completed.

Then, in step 107, the wafer WH which has been exposed is unloaded from the wafer holder 25 by an unloader (not shown). Thus, the exposure process for one wafer WH is completed.

In the subsequent exposure of the wafer, the step 10 is performed while the wavefront aberration relating to the projection optical system PL in steps 101 to 103 is measured and adjusted as needed.
Wafer exposure operations 4 to 107 are performed.

As described above, according to this embodiment.
For example, the measurement reticle RT has a width V that satisfies the condition (3).
Opening pattern 79X_k, 79Y_kTo form
Under the condition of illumination σ satisfying the condition of equation (4), the measurement retic
It illuminates the lens RT and is connected by the projection optical system PL.
Imaged aperture pattern 79X_k, 79Y_kAerial image of 79X
_k', 79Y_k′ Receive information about each light intensity distribution
Light surface 74X_k, 74Y_kPhotodetector 73X_k, 73
Y_kAsk all at once. And the required space image
79X_k', 79Y_k’Information about the respective light intensity distributions
Space image 79X _k', 79Y_k’Each position
After calculating the information, projection based on the calculated position information
The distortion of the optical system PL is calculated. Therefore asymmetric
By reducing the effect of aberration, distortion can be accurately corrected.
Can measure and quickly measure distortion
can do.

Further, the distortion aberration D obtained from only the position information of each of the spatial images 79X _k 'and 79Y _k ' is (1)
Since it is corrected by the formula, the projection optical system P
The distortion aberration of L can be measured.

Further, the projection optical system PL which is accurately obtained
Of the projection optical system PL is adjusted based on the distortion aberration of the projection optical system PL, and the predetermined pattern formed on the reticle R is projected onto the surface of the wafer WH by the projection optical system PL whose distortion aberration is sufficiently reduced. Pattern can be transferred onto the wafer WH with high accuracy.

In this embodiment, the light receiving surface 74X _k ,
Width W of 74Y _k is an aperture pattern 79X _k, but it was decided satisfy the width V of 79Y _k of equation (2), the light-receiving surface 74X _k, the width W of 74Y _k is W> beta · V It is also possible to satisfy the condition of (5). Further, instead of the photodetector pair 73 _k , for example, as shown in FIG. 16A, a photodetector having a square light-receiving surface 74 _k ′ having a side length W that satisfies the expression (5). 73 _k ′ are arranged in a matrix according to each pair of aperture patterns 79 _k (see FIG. 7).
It can also be used in place of 2.

When the photodetector 72 'shown in FIG. 16 (A) is used, the X initial position in step 112 and the Y initial position in step 114 of FIG. 6 in this embodiment are shown in FIG. 16 (B). The position of the wafer stage WST has a positional relationship between the light receiving surface 74 _k ′ and the aperture pattern images 79X _k ′ and 79Y _k ′ as shown in FIG. That is, at the X initial position, the outer edge of the light receiving surface 74 _k ′ on the + X direction side is located outside the −X direction side of the aperture pattern image 79X _k ′, and at the Y initial position, the light receiving surface 7
4 _k '-Y direction side of the outer edge of the opening pattern image 79X _k' to be positioned outside of the + Y direction side of the.

Further, the X direction in step 113 of FIG.
In the direction measurement, the light receiving surface 74 _kOn the + X direction side of
The outer edge is changed from the initial position shown in FIG.
Space image 79X shown in (B)_kPosition inside ’
After passing through the aerial image, the aerial image 79X shown in FIG.
_k'To the outside of the + X direction, the wafer stage
Move WST. And this wafer stage WS
During the movement of T, the light receiving surface 74 at each movement position_kTo
The amount of light that reaches the photodetector 73Y_kDetected by ’
Then, the detection result at each moving position is detected by the light detection data IMD.
1 is supplied to the main control system 20.

Further, the Y direction in step 115 of FIG.
In the direction measurement, the light receiving surface 74 _kOn the −Y direction side of
The outer edge is changed from the initial position shown in FIG.
Space image 79Y shown in (B)_kPosition inside ’
After passing through the aerial image 79Y, as shown in FIG.
_k'To the position outside the -Y direction of the wafer stage
Move WST. And this wafer stage WS
During the movement of T, the light receiving surface 74 at each movement position_kTo
The amount of light that reaches the photodetector 73Y_kDetected by ’
Then, the detection result at each moving position is detected by the light detection data IMD.
1 is supplied to the main control system 20.

The waveform corresponding to the result of the X moving light amount measurement on the aerial image 79X _k ′ thus obtained is the waveform JX _k ′ (X) shown by the solid line in FIG. And
Differential waveform d (JX _k '(X)) of this waveform JX _k ' (X)
/ DX is the aerial image 79 shown by the broken line in FIG.
It matches the light intensity distribution waveform IX _k ′ (X) of X _k ′ in the X direction. Therefore, in step 116 of FIG. 6, the waveform JX _k '(X) obtained by the X moving light amount measurement
And the barycentric position of the differential waveform d (JX _k '(X)) / dX is calculated to differentiate the X position X _k of the aerial image 79X _k '
Ask for. Further, 'the Y position Y _k of the aerial image 79X _k' spatial image 79Y _k obtained by similarly X position X _k of. Accordingly, the aerial image 79X _k 'with the same accuracy as that of the above embodiment.
It is possible to obtain the Y position Y _k of the X-position X _k and spatial image 79Y _k '.

<< Second Embodiment >> A second embodiment of the present invention will be described below. The exposure apparatus of this embodiment has the same configuration as the exposure apparatus 100 of the first embodiment, and is different from the first embodiment only in the configuration of the optical measurement device 70 in FIG. 2 described above. Focusing mainly on this difference, the present embodiment will be described below. In the description of the present embodiment, elements that are the same as or equivalent to those in the first embodiment will be assigned the same reference numerals and overlapping description will be omitted.

As shown in FIG. 20, the optical measuring device 70 according to this embodiment has a spatial image 79 of the aperture patterns 79X _k and 79Y _k formed on the above-described measurement reticle RT.
The light shield plate 75 is provided on the formation surface of X _k 'and 79Y _k ' and has an opening described later, a relay optical system 77 for relaying light through the light shield plate 75, and a relay optical system 77. A light detection unit 78 that detects the amount of light for each opening of the light blocking plate 75 that has passed through and a support member 81 that supports these are provided. This optical measuring device 70 is shown in FIG.
As shown in FIG. 5, a part thereof is embedded in the wafer stage WST and moves integrally with the wafer stage WST.

As shown in FIG. 21, the light shielding plate 75 has a rectangular opening 76X _k whose longitudinal direction is in the Y-axis direction.
And a pair of openings 76 _k each having a rectangular opening 76Y _k extending in the X-axis direction are arranged in a matrix with an X-direction pitch PT and a Y-direction pitch PT. here,
The opening 76X _k has a width W in the X direction and a width LM (> W) in the Y direction.
Has a rectangular shape with an opening 76Y _k of X
It has a rectangular shape having a width LM in the direction and a width W in the Y direction.
That is, the opening 76X _k in the light shielding plate 75, the sequence of 76Y _k is the light receiving surface 7 in the photodetector section 72 of the first embodiment
It is the same as the arrangement of 4X _k and 74Y _k .

The relay optical system 77 may be composed of a single lens or a combination of a plurality of lenses.

Here, the numerical aperture NA _R of the relay optical system 77
Opening 76X _k, the set of width W in the 76Y _k explains. If the numerical aperture NA _R of the relay optical system 77 is small,
Since only part of the light transmitted through the light shielding plate 75 can be used as signal light, it is generally disadvantageous for accurate position measurement of the aerial images 79X _k ′, 79Y _k ′. On the other hand, when the numerical aperture NA _R of the relay optical system 77 increases, the optical measuring device 7
0 will increase in size.

Therefore, when the projection optical system PL has coma as in the case of FIG. 6, the inventor of the present invention shifts the position of the aerial image measured as described later (hereinafter, simply referred to as “positional shift”). the "also referred to), the numerical aperture NA _R and opening 76X _k of the relay optical system 77 associated with the amount of light that can be used as signal light, for the various combinations of the width W of 76Y _k, the σ configurable lighting at the time of measurement The simulation was performed while changing. 22 (A) to 22
In (C), in this simulation, the measurement wavelength is 193 nm, the numerical aperture NA ₀ of the projection optical system PL is 0.7.
A representative simulation result when 5 is set is shown. That is, in FIG. 22A, the width W = 100n
In the case of m, the state of occurrence of positional deviation due to the combination of the numerical aperture NA _R and the illumination σ is shown, and FIG.
FIG. 22C shows the occurrence of positional deviation due to the combination of the numerical aperture NA _R and the illumination σ when the width W = 200 nm, and FIG. 22C shows the numerical aperture NA _R when the width W = 500 nm. The situation of occurrence of the positional deviation due to the combination of and the illumination σ is shown.

As shown in FIG. 22A, the width W = 1
In the case of 00 nm, regardless of the value of numerical aperture NA _R ,
By adjusting the value of the illumination σ, the positional deviation can be made zero. On the other hand, as shown in FIG. 22B, when the width W = 200 nm, the numerical aperture NA _R ≧
If it is about 0.5, the positional deviation can be made zero by adjusting the value of the illumination σ. Furthermore, FIG.
As shown in (C), in the case of the width W = 500 nm, if the numerical aperture NA _R ≧ 0.6, the positional deviation can be made zero by adjusting the value of the illumination σ. .

From the simulation results including FIGS. 22A to 22C described above, the present inventor found the following (i) to
If one of the three conditions shown in (iii) is satisfied,
It has been found that the displacement can be reduced. (I) NA _R = arbitrary (W ≦ 0.5 × λ / N
A _O ) (ii) NA _R ≧ NA _O × 0.5 (0.5 × λ / NA _O ≦ W
≦ 2 × λ / NA _O ) (iii) NA _R ≧ NA _O × 0.8 (W ≧ 2 × λ / N
A _O )

Further, in consideration of the illumination σ, it has been found that the positional deviation can be reduced by satisfying one of the three conditions shown in the following (i ') to (iii'). (i ′) NA _R = arbitrary, σ = arbitrary (W ≦ 0.5 × λ / N
A _O ) (ii ′) NA _R ≧ NA _O × 0.5, σ> 0.6 (0.5 × λ / NA _O
≦ W ≦ 2 × λ / NA _O ) (iii ′) NA _R ≧ NA _O × 0.8, σ> 0.6 (W ≧ 2 × λ / N
A _O )

In the present embodiment, the above (i ') to (ii).
In addition to satisfying any of the conditions of i '), the condition of the above-mentioned expression (3) is also satisfied.

Returning to FIG. 20, the photo-detecting section 78 is similar to that shown in FIG.
As shown in FIG. 3, for each aperture pair 76 _k , the aperture 76X _k
Light detector 80X _k that receives all the light that has passed through and detects the amount of light, and photodetector 80Y _k that receives all the light that has passed through aperture 76Y _k and that detects the amount of light The device pairs 80 _k are arranged on the upper surface of the photodetector 78 at the same pitch as the arrangement pitch PT of the aperture pairs 76 _k in the light shielding plate 75. In order to receiving all the light passing through the aperture 76X _k, the light-receiving surface 82X _k photodetector 80X _k is
It is set to be slightly larger than the opening 76X _k . Further, since the receiving all the light that has passed through the opening 76Y _k, the light-receiving surface 82Y _k photodetector 80Y _k is set slightly larger than the opening 76Y _k. That is, the light receiving surface 82X
_The width in the X direction of _{k and} the width in the Y direction of the light receiving surface 82Y _k are W ′ (>
W), and the width of the light receiving surface 82X _{k in} the Y direction and the width of the light receiving surface 82Y _{k in} the X direction are LM ′ (> LM). The photodetection results by the photodetectors 80X _k and 80Y _k are
The light detection data IMD1 is supplied to the main control system 20.

Exposure of this embodiment configured as described above
In the device 100, the projection is performed in the same manner as in the first embodiment.
The distortion aberration of the shadow optical system PL is measured. That is, the opening 7
6X _k, 76Y_kHowever, the light receiving surface 74 in the first embodiment
X_k, 74Y_kOptical measurement device so that the position corresponds to
72 'position, that is, the position of wafer stage WST is controlled.
In steps 112 to 115 in FIG.
X initial position setting, X direction movement measurement, Y initial position setting, and
And Y direction movement measurement. And, in the case of the first embodiment
In steps 116 and 117, the
Turn image 79X _k', 79Y_k’Position information is calculated and
The distortion of the projection optical system PL is collected based on the positional information that is output.
The difference D0 is calculated.

Thereafter, as in the case of the first embodiment, steps 102 to 107 are executed, and the exposure process for one wafer WH is performed.

As described above, according to the present embodiment, in order to set the measurement area in which the degree of coincidence with the formation surface of the aerial images 79X _k ′, 79Y _k ′, that is, high flatness is set, a high flat surface is set. using the easy shielding plate 75 achieved in degrees, measurement area or openings 76X _k, by relaying by the relay optical system 77 light that has reached the 76Y _k, measuring the amount of the relay optical aerial image 79X Information about the light intensity distributions of _k 'and 79Y _k ' is provided to the photodetectors 80X _k ,
80Y _k requests all at once. The image obtained spatial 79X _k from the information on ', 79Y _k' respective light intensity distribution, the spatial image 79X _k after calculating the ', 79Y _k' respective location information, based on the calculated position information,
The distortion of the projection optical system PL is calculated. Therefore, the distortion aberration can be accurately measured, and the distortion aberration can be quickly measured.

[0145] The opening 76X _k of the light shielding plate 75, 76Y _k
Width W, the numerical aperture NA _R of the relay optical system 77, and the illumination σ
With respect to the above, since the setting is made to satisfy one of the three conditions shown in (i ′) to (iii ′) above, the distortion aberration can be measured with high accuracy.

Further, as in the first embodiment, the spatial image 7
The distortion aberration D of the projection optical system PL can be measured very accurately by correcting the distortion aberration D obtained from only the position information of each of 9X _k 'and 79Y _k ' by the equation (1).

Further, the projection optical system PL which is accurately obtained
Of the projection optical system PL is adjusted based on the distortion aberration of the projection optical system PL, and the predetermined pattern formed on the reticle R is projected onto the surface of the wafer WH by the projection optical system PL whose distortion aberration is sufficiently reduced. Pattern can be transferred onto the wafer WH with high accuracy.

Also in this embodiment, as in the case of the first embodiment, the openings 76X _k ,
The width W of 76Y _k can also be set so as to satisfy the condition of the above formula (5). That is, in this embodiment, as shown in FIG.
Same shape as the light receiving surface 74X _k, 74Y _k similar shape and opening 76X _k in the arrangement, it is assumed that forming the 76Y _k to the light shielding plate 75, the light receiving surface 74 _k illustrated in FIG. 16 (A) 'in Alternatively, the openings may be formed in the light shielding plate 75.
In this case, the shape and arrangement of the light receiving surface of the photodetector in the photodetector 78 correspond to the shape and arrangement of the openings in the light shielding plate 75. In this case, the opening 76X _k of the light shielding plate 75, the width W of 76Y _k, the numerical aperture NA _R of the relay optical system 77, and the illumination sigma, the above (ii
It is sufficient to satisfy the three conditions shown in i ').

Further, in the present embodiment, the optical measuring device 70 is integrally moved, but in the X, Y movement measurement, only the light shielding plate 75 may be moved.

In each of the above embodiments, the optical measurement device 70 was moved with the measurement reticle RT stopped in measuring the distortion aberration. However, the measurement reticle RT was used with the optical measurement device 70 stopped. The RT may be moved. Further, both the optical measuring device 70 and the measurement reticle RT can be moved.

Further, in each of the above-described embodiments, the measurement reticle RT has 25 aperture patterns and is arranged in a matrix. However, the number may be increased or decreased or the arrangement position may be changed according to the desired measurement accuracy of the distortion. May be changed. In this case, the measurement area, that is, the light-receiving surfaces 74X _k and 74Y _k in the first embodiment and the openings 76X _k and 76Y in the second embodiment are determined depending on the number and arrangement positions of the opening patterns in the measurement reticle RT. _It suffices to determine the number of _k and the arrangement position.

Further, in each of the above-described embodiments, the pattern for detecting the position information on the measurement reticle RT is rectangular, but it is also possible to use a pattern of another shape.

In each of the above embodiments, the optical measuring device 70 is integrated with the wafer stage WST, but the optical measuring device 70 may be detachable from the wafer stage WST.

In each of the above embodiments, the case of the scanning type exposure apparatus has been described, but the present invention is not limited to the step-and-repeat machine as long as it is an exposure apparatus having a projection optical system.
It can be applied regardless of the step-and-scan machine and the step-and-stitching machine.

Further, in each of the above-described embodiments, the present invention is applied to the measurement of the distortion aberration of the projection optical system in the exposure apparatus, but the distortion aberration of the imaging optical system in other types of apparatus is not limited to the exposure apparatus. The present invention can also be applied to measurement.

Furthermore, the present invention can be applied to the measurement of the optical characteristics of various optical systems such as the shape of a reflecting mirror other than the measurement of the distortion aberration of the optical system.

<< Manufacture of Device >> Next, manufacture of a device using the exposure apparatus of each of the above-described embodiments will be described.

FIG. 24 shows devices (semiconductor chips such as IC and LSI, liquid crystal panels, CCs, etc.) in this embodiment.
D, thin film magnetic head, micromachine, etc.) flow chart is shown. As shown in FIG. 24,
First, in step 201 (design step), functional design of a device (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Subsequently, in step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step 204 (wafer processing step), the mask and wafer prepared in steps 201 to 203 are used to form an actual circuit or the like on the wafer by lithography, as will be described later. Next, step 205 (device assembly step)
At step 204, the wafer processed at step 204 is made into chips. This step 205 includes an assembly process (dicing, bonding), a packaging process (chip encapsulation), and the like.

Finally, step 206 (inspection step)
In step 2, inspections such as an operation confirmation test and a durability test of the device manufactured in step 205 are performed. After these steps, the device is completed and shipped.

FIG. 25 shows a detailed flow example of step 204 in the case of a semiconductor device. In FIG. 25, step 211 (oxidation step)
In, the surface of the wafer is oxidized. Step 212
In the (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode forming step), electrodes are formed on the wafer by vapor deposition. Step two
In 14 (ion implantation step), ions are implanted in the wafer. Steps 211 to 214 above
Each of them constitutes a pretreatment process of each stage of the wafer process, and is selected and executed according to the required treatment in each stage.

At each stage of the wafer process, when the pretreatment process is completed, the posttreatment process is executed as follows. In this post-processing step, first, step 215
In the (resist formation step), a photosensitive agent is applied to the wafer, and subsequently, in step 216 (exposure step), the circuit pattern of the mask is printed and exposed on the wafer by the exposure apparatus and the exposure method of the embodiment described above. Next, in step 217 (developing step), the exposed wafer is developed, and then in step 218.
In the (etching step), the exposed member of the portion other than the portion where the resist remains is removed by etching. Then, in step 219 (resist removing step), the unnecessary resist after etching is removed.

By repeating these pre-processing step and post-processing step, multiple circuit patterns are formed on the wafer.

As described above, a device in which a fine pattern is accurately formed is manufactured.

[0165]

As described above in detail, according to the optical characteristic measuring method of the present invention, the optical characteristic of the optical system to be tested can be measured quickly and accurately.

Further, according to the optical characteristic measuring apparatus of the present invention, the optical characteristic of the optical system to be measured is measured by using the optical characteristic measuring method of the present invention. Therefore, the optical characteristic of the optical system to be measured can be quickly measured. And it can be detected with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an exposure apparatus according to a first embodiment.

FIG. 2 is a diagram showing a configuration of the optical measurement device of FIG.

FIG. 3 is a diagram showing a configuration of a photodetector section in FIG.

FIG. 4 is a block diagram showing a configuration of a main control system of FIG.

5 is a flowchart for explaining a process in an exposure operation by the apparatus of FIG.

FIG. 6 is a flowchart for explaining a process in a distortion aberration measurement subroutine of FIG.

FIG. 7 is a diagram showing an example of a measurement pattern formed on a measurement reticle.

8A and 8B are views for explaining a difference in influence of asymmetric aberration due to the width of the measurement pattern in FIG. 7.

FIG. 9A is a diagram showing the amount of positional deviation due to third-order coma aberration for each combination of the width of the measurement pattern and the illumination σ, and FIG. 9B shows the measurement pattern. Width and lighting σ
It is a figure which shows the positional shift amount by 5th-order coma aberration for every combination with.

FIG. 10 is a diagram showing positional deviation amounts due to third-order, fifth-order, and seventh-order coma aberrations for each illumination σ.

FIG. 11 is a diagram for explaining a positional relationship between an aerial image and a light receiving surface (measurement region) at an initial position of moving light amount measurement.

12 (A) to 12 (C) are diagrams for explaining the transition of the positional relationship between the aerial image and the light receiving surface (measurement region) by the moving light amount measurement in the X direction in the first embodiment. It is a figure.

13A to 13C are views for explaining the transition of the positional relationship between the aerial image and the light receiving surface (measurement region) by the moving light amount measurement in the Y direction in the first embodiment. It is a figure.

14A to 14C are diagrams for explaining a waveform obtained by the moving light amount measurement in the first embodiment.

FIG. 15 is a diagram for explaining threshold processing.

FIG. 16 (A) is a diagram showing a configuration of a modified example of the light detection unit, and FIG. 16 (B) is a spatial image and a light receiving surface (measurement area) at an initial position of the moving light amount measurement according to the modified example. ) Is a diagram for explaining a positional relationship with FIG.

17A to 17C are diagrams for explaining the transition of the positional relationship between the aerial image and the light receiving surface (measurement region) by the moving light amount measurement in the X direction in the modification. is there.

FIG. 18A to FIG. 18C are diagrams for explaining a transition of a positional relationship between an aerial image and a light receiving surface (measurement region) by a moving light amount measurement in the Y direction in a modified example. is there.

FIG. 19 is a diagram for explaining a waveform obtained by measuring the amount of moving light in a modified example.

FIG. 20 is a diagram showing a configuration of an optical measurement device according to a second embodiment.

FIG. 21 is a diagram showing a configuration of the light shielding plate of FIG. 20.

22 (A) to 22 (C) are diagrams showing the amount of positional deviation due to coma aberration for each combination of the width of the aperture of the light shielding plate, the numerical aperture of the relay optical system, and the illumination σ. .

FIG. 23 is a diagram showing a configuration of a photodetector section in FIG. 20.

FIG. 24 is a flowchart for explaining a device manufacturing method using the exposure apparatus of each embodiment.

FIG. 25 is a flowchart of processing in the wafer processing step of FIG. 24.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Illumination system, 24 ... Wafer stage drive part (driving device), 32 ... Position information calculation device, 33 ... Optical characteristic calculation device, 34 ... Optical characteristic correction arithmetic device, 72, 72 '... Photodetection part (photodetection device) ), 74X _k , 74Y _k ... Light receiving surface (measurement area), 75 ... Light-shielding plate (light selection member), 76X _k , 76
Y _k ... Aperture (measurement area), 77 ... Relay optical system, 78 ...
Light detector (photodetector), 79X _k, 79Y _k ... aperture pattern _{(pattern), 79X k ', 79Y k} ' ... aerial image, P
L ... Projection optical system (test optical system, optical system), RT ... Measurement reticle (mask), WH ... Wafer (substrate).

Claims (27)

[Claims] 1. An optical characteristic measuring method for measuring optical characteristics of an optical system under test having an imaging magnification β and a numerical aperture NA _O , wherein light having a predetermined wavelength λ is expressed as V> λ / (NA _O · β) An illumination step of irradiating a mask having a width V in a predetermined direction that satisfies the condition of (1) and having a plurality of patterns extending in a direction intersecting the predetermined direction; An aerial image forming step of forming aerial images of the plurality of patterns by interposing an optical system; a plurality of measurement regions and the aerial image provided on a surface of the aerial image formation corresponding to the plurality of patterns, respectively. While changing the positional relationship between the mask and the plurality of measurement areas so that the positional relationship between the mask and the measurement area changes along the conjugate direction of the predetermined direction on the formation surface of the aerial image, Simultaneously adjust the amount of light reaching A light detection step of detecting the aerial image of each of the plurality of patterns based on a change in the amount of light reaching each of the plurality of measurement regions due to a change in the positional relationship between the plurality of measurement regions and the aerial image. A position information calculating step of calculating position information regarding the conjugate direction for each; and using the calculated position information,
An optical characteristic measuring method, comprising: an optical characteristic calculating step of calculating an optical characteristic of the test optical system. 2. In the illuminating step, the mask is irradiated with the light having the predetermined wavelength under an illumination condition in which an illumination coherence factor of the optical system under test is larger than 0.6. The optical characteristic measuring method described. 3. An optical characteristic measuring method for measuring an optical characteristic of an optical system to be inspected, which comprises irradiating a mask having a plurality of patterns extending in a direction intersecting a predetermined direction with light having a predetermined wavelength. When;
An aerial image forming step of making light through the mask incident on the optical system to be inspected to form aerial images of the plurality of patterns; provided on a surface on which the aerial image is formed in accordance with each of the plurality of patterns. While changing the positional relationship between the mask and the plurality of measurement areas so that the positional relationship between the plurality of measurement areas and the aerial image changes along the conjugate direction of the predetermined direction on the formation surface of the aerial image. A light detection step of relaying the light reaching the plurality of measurement areas by a relay optical system and detecting the light amount of the relayed light; and the light detection step in accordance with a change in the positional relationship between the plurality of measurement areas and the aerial image. A position information calculating step of calculating position information regarding the conjugate direction for each aerial image of each of the plurality of patterns based on a change in the amount of light reaching each of the plurality of measurement regions; Optical characteristic measuring method comprising; using location information, and the optical characteristic calculation step of calculating the optical characteristic of the target optical system. 4. When the imaging magnification of the optical system to be tested is β, the numerical aperture is NA ₀ , and the predetermined wavelength is λ, the width V of the pattern in the predetermined direction is V> λ / (NA The optical characteristic measuring method according to claim 3, wherein the condition of _O · β) is satisfied. 5. In the illuminating step, the mask is irradiated with the light having the predetermined wavelength under an illumination condition in which an illumination coherence factor of the optical system to be tested is larger than 0.6. The optical characteristic measuring method described in. Wherein said numerical aperture NA _O of the optical system to be measured, the numerical aperture NA _R of the relay optical system, the predetermined wavelength lambda, when the width of the measurement region related to the conjugated direction is W, NA _R = arbitrary (W ≤ 0.5 x λ / NA _O ) NA _R ≥ NA _O x 0.5 (0.5 x λ / NA _O ≤ W ≤ 2 x
5. The method for measuring optical characteristics according to claim 3, wherein any one of the three conditions represented by λ / NA _O ) NA _R ≧ NA _O × 0.8 (W ≧ 2 × λ / NA _O ). . Wherein said numerical aperture NA _O of the optical system to be measured, the numerical aperture NA _R of the relay optical system, the predetermined wavelength lambda, the illumination coherence factor of the target optical system sigma, relating to the conjugated direction When the width of the measurement region is W, NA _R = arbitrary, σ = arbitrary (W ≦ 0.5 × λ / NA _O ) NA _R ≧ NA _O × 0.5, σ> 0.6 (0.5 × λ / NA _O ≦ W ≦
4. The method according to claim 3, wherein any one of the three conditions represented by 2 × λ / NA _O ) NA _R ≧ NA _O × 0.8 and σ> 0.6 (W ≧ 2 × λ / NA _O ). Optical property measurement method. 8. When the imaging magnification of the optical system to be tested is β and the width of the pattern in the predetermined direction is V, the condition of V> λ / (NA _O · β) is further satisfied. The optical characteristic measuring method according to claim 7. 9. The width of the measurement area in the conjugate direction is equal to or less than the width of the aerial image of the pattern in the conjugate direction, and in the position calculation step, a change in the amount of light reaching each of the plurality of measurement areas. The position information is calculated for each aerial image of each of the plurality of patterns by obtaining the barycentric position for each waveform that reflects
9. The optical property measuring method according to any one of items 8 to 8. 10. The width of the measurement area in the conjugate direction is larger than the width of the aerial image of the pattern in the conjugate direction, and in the position calculation step, a change in the light amount of light reaching each of the plurality of measurement areas is calculated. 9. The optical characteristic according to claim 1, wherein position information is calculated for each aerial image of each of the plurality of patterns by obtaining a barycentric position for each waveform that reflects a differential waveform. Measuring method. 11. The optical characteristic measuring method according to claim 1, wherein the optical characteristic is a distortion aberration. 12. An optical characteristic correction calculation step for correcting distortion aberration of the optical system to be measured, which has been obtained in the optical characteristic calculation step, based on previously measured asymmetrical aberration information of the optical system to be measured. The optical characteristic measuring method according to claim 11, wherein: 13. An optical characteristic measuring device for measuring optical characteristics of an optical system under test having an imaging magnification β and a numerical aperture NA _O , wherein light having a predetermined wavelength λ is expressed as V> λ / (NA _O · β) An illumination system for irradiating a mask having a width V in a predetermined direction satisfying the condition of (1) and having a plurality of patterns extending in a direction intersecting the predetermined direction; and light passing through the plurality of patterns formed in the mask. On the formation surface of the aerial image of the plurality of patterns formed by passing through the test optical system, the light amount of the light reaching each of the plurality of measurement regions provided corresponding to each of the plurality of patterns is simultaneously measured. A photodetection device for detecting; the mask and the plurality of measurement regions such that the positional relationship between the plurality of measurement regions and the aerial image changes along the conjugate direction of the predetermined direction on the formation surface of the aerial image. Positional relationship with A driving device that changes the engagement of each of the plurality of patterns based on a change in the amount of light that reaches each of the plurality of measurement regions due to a change in the positional relationship between the plurality of measurement regions and the aerial image of the pattern. An optical characteristic calculation device that calculates positional information about the conjugate direction for each aerial image; and an optical characteristic calculation device that calculates the optical characteristic of the optical system to be tested using the calculated positional information. measuring device. 14. The illumination system illuminates the mask with the light having a predetermined wavelength under an illumination condition in which an illumination coherence factor of the optical system to be tested is larger than 0.6. The optical characteristic measuring device described in. 15. An optical characteristic measuring device for measuring an optical characteristic of an optical system to be inspected, the illumination system irradiating a mask having a plurality of patterns extending in a direction intersecting a predetermined direction with light of a predetermined wavelength. And; a plurality of light beams that have passed through the plurality of patterns are arranged on a surface on which an aerial image of the plurality of patterns is formed by passing through the optical system to be inspected, and a plurality of light beams are provided corresponding to the plurality of patterns. A light selection member for selecting the light reaching the measurement region; a relay optical system for relaying the light selected by the light selection member; and a light amount of the light relayed by the relay optical system for each of the plurality of measurement regions. A photodetection device for detecting at the same time; the marker so that the positional relationship between the plurality of measurement regions and the aerial image changes along the conjugate direction of the predetermined direction on the formation surface of the aerial image. A driving device for varying the positional relationship between the click and the optical selection member;
Position information about the conjugate direction for each aerial image of each of the plurality of patterns based on a change in the amount of light that has reached the measuring region due to a change in the positional relationship between the plurality of measurement regions and the aerial image of the pattern. An optical characteristic measuring device comprising: a position information calculating device for calculating; and an optical characteristic calculating device for calculating an optical characteristic of the optical system to be tested using the calculated position information. 16. The imaging magnification of the optical system to be tested is β,
The width V of the pattern in a predetermined direction satisfies a condition of V> λ / (NA _O · β), where NA ₀ is NA ₀ and the predetermined wavelength is λ. Optical characteristic measuring device. 17. The illumination system irradiates the measurement mask with light having the predetermined wavelength under an illumination condition in which an illumination coherence factor of the optical system to be tested is larger than 0.6. Item 16. The optical characteristic measuring device according to item 16. 18. The numerical aperture of the optical system under test is NA _O , the numerical aperture of the relay optical system is NA _R , the predetermined wavelength is λ,
When the width of the measurement region in the conjugate direction is W, NA _R = arbitrary (W ≦ 0.5 × λ / NA _O ) NA _R ≧ NA _O × 0.5 (0.5 × λ / NA _O ≦ W ≦ 2 ×
The optical characteristic measuring device according to claim 15 or 16, wherein any one of the three conditions represented by λ / NA _O ) NA _R ≧ NA _O × 0.8 (W ≧ 2 × λ / NA _O ). . 19. The numerical aperture of the optical system under test is NA _O , the numerical aperture of the relay optical system is NA _R , the predetermined wavelength is λ,
When the illumination coherence factor of the test optical system is σ and the width of the measurement region in the conjugate direction of the test optical system in the predetermined direction is W, NA _R = arbitrary, σ = arbitrary (W ≦ 0.5 × λ / NA _O ) NA _R ≧ NA _O × 0.5, σ> 0.6 (0.5 × λ / NA _O ≦ W ≦
The method according to claim 15, wherein any one of the three conditions represented by 2 × λ / NA _O ) NA _R ≧ NA _O × 0.8 and σ> 0.6 (W ≧ 2 × λ / NA _O ). Optical property measuring device. 20. When the imaging magnification of the optical system to be tested is β and the width of the pattern in the predetermined direction is V, the condition of V> λ / (NA _O · β) is further satisfied. 20. The optical characteristic measuring device according to claim 19. 21. The optical characteristic measuring device according to claim 13, wherein the optical characteristic is distortion. 22. An optical characteristic correction calculation device for correcting distortion aberration of the optical system to be measured, which is obtained by the optical characteristic calculation device, based on previously measured asymmetrical aberration information of the optical system to be measured. 2. The method according to claim 2, wherein
1. The optical characteristic measuring device described in 1. 23. By irradiating the substrate with exposure light,
23. An exposure device for transferring a predetermined pattern onto the substrate, comprising: a projection optical system arranged on an optical path of exposure light; and the projection optical system being a test optical system. An exposure apparatus comprising: 24. An optical system whose optical characteristic is measured by using the optical characteristic measuring method according to claim 1. 25. An optical system whose optical characteristic is measured by the optical characteristic measuring device according to any one of claims 13 to 22. 26. An optical characteristic adjusting method for adjusting an optical characteristic of an optical system, wherein the optical characteristic of the optical system is measured by using the optical characteristic measuring method according to claim 1. An optical characteristic adjusting step of adjusting the optical characteristic of the optical system based on a measurement result in the optical characteristic measuring step. 27. A semiconductor device manufactured by using the exposure apparatus according to claim 23.