JP2002005787A - Measuring method for image forming characteristic, measuring device for image forming characteristic, exposure method, exposure device, and manufacturing method for device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method for an image forming characteristic, a measuring device for an image forming characteristic, an exposure method, an exposure device, and a manufacturing method for a device, capable of accurately measuring the image forming characteristic of an optical system in a simple constitution. SOLUTION: The measuring device S for the image characteristic for measuring a numerical aperture of a projecting optical system PL has a mask M for generating diffraction light DL having different incident angles θ on the projecting optical system PL by the illumination of exposure light EL; a detector A capable of detecting the amount of light of the diffraction light DL passed through the projecting optical system PL; and an arithmetic unit CONT for calculating the numerical aperture NA of the projecting optical system PL based on the variation of the amount of light of the diffraction light DL having different incident angles θdetected with the detector A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging characteristic measuring method for measuring an imaging characteristic of an optical system, an imaging characteristic measuring apparatus, an exposure method, an exposure apparatus, and a device manufacturing method.

[0002]

2. Description of the Related Art Conventionally, various types of exposure apparatuses have been used when manufacturing semiconductor elements, thin film magnetic heads, liquid crystal display elements, and the like by a photolithography process. Such an exposure apparatus illuminates a mask provided with a pattern from an illumination optical system with exposure illumination light (exposure light), and transmits the light transmitted through the mask onto a substrate coated with a photosensitive agent via a projection optical system. Exposure processing is performed by projecting an image of the pattern.
At this time, in order to project the image of the pattern formed on the mask onto the substrate with high accuracy, it is important to understand the imaging characteristics of the projection optical system, especially the numerical aperture NA.

[0003]

However, in the prior art, there is no effective method for measuring the numerical aperture NA of the projection optical system, and in order to grasp the numerical aperture NA, the resolution R of the projection optical system must be determined. The numerical aperture NA was calculated from the obtained resolution R. Specifically, first, a mask provided with patterns having various line widths is irradiated with exposure light, and an image of the pattern formed on the mask is projected and exposed on a photosensitive substrate via a projection optical system. Next, a development process is performed on the exposed photosensitive substrate, and the line width of the pattern formed on the photosensitive substrate is measured by a line width measuring device such as an SEM. Then, the resolution R of the projection optical system is obtained from the measurement result of the line width of the pattern, and the aperture R of the projection optical system is determined from the resolution R and the wavelength λ of the exposure light based on the relationship of “R = λ / NA”. I was looking for a number NA. However, since the resolution R is affected by the resist characteristics (process factor), the numerical aperture NA cannot be unambiguously determined from the resolution R by the above-described method. That is, the absolute value of the numerical aperture NA could not be obtained.

In some cases, the numerical aperture NA of the projection optical system differs at an arbitrary position in an exposure area due to the influence of aberration.
At this time, there is a problem that the size of the pattern formed on the substrate differs depending on the position in the exposure region. Therefore, it is necessary to measure the numerical aperture corresponding to each position in the exposure area of the projection optical system and perform appropriate processing based on the measurement result. However, it is effective to accurately measure the distribution of the numerical aperture NA at a plurality of positions. There was no way.

The present invention has been made in view of such circumstances, and an imaging characteristic measuring method, an imaging characteristic measuring apparatus, and an exposing method capable of accurately measuring the imaging characteristics of an optical system with a simple configuration. , An exposure apparatus, and a device manufacturing method.

[0006]

In order to solve the above-mentioned problems, the present invention employs the following structure corresponding to FIGS. 1 to 9 shown in the embodiment. The imaging characteristic measuring method of the present invention is the same as the imaging characteristic measuring method for measuring the imaging characteristic of the optical system (PL), wherein the first light (D) at the first incident angle (θ) is used.
L) is incident on the optical system (PL).
The optical information of the first light (DL) that has passed through is detected, and the second light (DL) is incident on the optical system (PL) at an incident angle (θ) different from the first incident angle (θ). , This optical system (P
L), the optical information of the second light (DL) having passed therethrough is detected, and based on the optical information of the first light (DL) and the optical information of the second light (DL), The numerical aperture (NA) of the optical system (PL) is calculated.

According to the present invention, the first light (DL) and the second light (DL) are respectively incident on the projection optical system (PL) at different incident angles (θ), and the projection optical system (PL) The optical information of the first and second lights passing through the optical system (PL) is detected, and the critical incident angle of the light that can pass through the optical system (PL) is determined based on the optical information, for example, based on a change in the amount of light. You can ask. Then, the numerical aperture (NA) of the optical system (PL) can be obtained as the imaging characteristic based on the obtained critical angle of incidence. As described above, the optical system has a simple configuration in which the first and second lights are made to enter the optical system (PL) at different incident angles and the optical information of the light passing through the optical system (PL) is detected. The numerical aperture (NA) of (PL) can be obtained with high accuracy.

At this time, on the object plane side of the optical system (PL),
First pattern (PA) formed at a predetermined pitch (P)
By disposing a mask (M) on which at least a second pattern (PA) formed at a pitch (P) different from the predetermined pitch (P) is formed, the first light (DL)
Is generated when the first pattern (PA) is illuminated, and the second light (DL) is generated when the second pattern (PA) is illuminated. At this time, the incident angle (θ) of the light incident on the optical system (PL) can be easily adjusted by changing the pitch (P) of the pattern (PA), so that the configuration can be efficiently performed with a simple configuration. The numerical aperture (NA) can be measured.

The first and second patterns (PA) formed on the mask (M) include illumination light (E) transmitted through the mask (M).
L) having a phase shift unit (52) for changing the phase of
The first light (DL) incident on the optical system (PL) is a ± 1st-order diffracted light (DLp, Dp) generated from the first pattern (PA).
Lm) and the second light (D) incident on the optical system (PL).
L) is ± 1st-order diffracted light (DLp, DLm) generated from the second pattern (PA). That is, the pattern (P
By providing the phase shift unit (52) in A),
Of the diffracted light (DL) generated by illuminating the pattern (PA) with the illumination light (EL), the zero-order diffracted light (DLz) is not generated. It is possible to adopt a configuration in which two light beams (DLp and DLm) are incident. By not generating the 0th-order diffracted light (DLz), when detecting the optical information of the ± 1st-order diffracted light (DLp, DLm) that has passed through the optical system (PL), the accuracy is not affected by the 0th-order diffracted light (DLz). It can be detected well.

The mask (M2) is illuminated from an oblique direction with respect to the optical axis (AX) of the optical system (PL), and the first light (DL) incident on the optical system (PL) is converted into a first pattern (PA). ), One of the ± 1st-order diffracted lights (DLp, DLm),
Zero-order diffracted light (DL) generated from the first pattern (PA)
z), and the second light (DL) incident on the optical system (PL)
Can be defined as one of the ± first-order diffracted lights (DLp, DLm) generated from the second pattern (PA) and the zero-order diffracted light (DLz) generated from the second pattern (PA).
Also in this case, the two light beams (DL) are transmitted to the optical system (PL).
z and DLp or DLz and DLm), so that the 0th-order diffracted light (DL) that has passed through the optical system (PL)
When detecting optical information of z) and one of the ± 1st-order diffracted lights (DLp, DLm), accurate detection can be performed.

The first light (DL) is applied to a first pattern (P
The second light (DL) is defined as a 0th-order diffracted light (DLz) and ± 1st-order diffracted lights (DLp, DLm) generated from A).
The 0th-order diffracted light (DLz) and ± 1st-order diffracted light (DLp, DLm) generated from the pattern (PA) are set, and each of the 0th-order diffracted light (DLz) is restricted from reaching the image plane of the optical system (PL). Also, since only two light beams (DLp and DLm) reach the image plane side of the optical system (PL), the ± 1st-order diffracted lights (DLp and DLm) that have passed through the optical system (PL) can be obtained. Optical information can be accurately detected.

The mask (M) has a first pattern (PA1).
And a plurality of patterns (PA2, PA4 to PA9) formed at pitches (P2, P4 to P9) different from the pitch (P1) of the second pattern (PA3) and the pitch (P3) of the second pattern (PA3). The mask (M) is irradiated with the illumination light (EL), and the first pattern (PA1) and the second pattern (PA3) and a plurality of patterns (PA2, PA4 to PA9) are irradiated by the illumination light (EL). ) Are incident on the optical system (PL), and among the light generated by the plurality of patterns (PA2, PA4 to PA9), the light that can pass through the optical system (PL) is generated. A pattern (PA2) having a pitch (P2) is specified, and a numerical aperture (NA) can be calculated based on the specified pattern (PA2) and a predetermined wavelength (λ) of the illumination light (EL). . Then, by setting the number of a plurality of patterns (PA2, PA4 to PA9) according to the accuracy of the numerical aperture (NA) to be obtained, the numerical aperture (NA) can be obtained with desired accuracy.

The light (EL, DL) is used as exposure illumination light, and by detecting whether or not a projection image is projected on a photosensitive substrate (W) arranged on an image plane of the optical system (PL), Optical information of the light that has passed through the optical system (PL) can be detected.

According to the above-described imaging characteristic measuring method, a first light (DL) having a first incident angle (θ) is used in an imaging characteristic measuring apparatus for measuring the imaging characteristic of an optical system (PL).
And a mask (M) for generating a second light (DL) having an incident angle (θ) different from the first incident angle (θ), and a first light passing through the optical system (PL) (DL)
(A) for detecting the second light (DL) having passed through the optical system (PL), and the first light detected by the detector (A).
An arithmetic unit (CONT) for calculating the numerical aperture (NA) of the optical system (PL) as the imaging characteristic based on the optical information of the light (DL) and the optical information of the second light (DL). And an imaging characteristic measuring apparatus (S) characterized by having the following.

The imaging characteristic measuring device (S) includes:
By providing an adjusting device (40) for adjusting the numerical aperture (NA) of the optical system (PL) based on the numerical aperture (NA) calculated by the arithmetic unit (CONT), a desired numerical aperture (NA) is provided. Can be obtained.

According to the exposure apparatus of the present invention, an illumination optical system (2) for illuminating a mask (M) with illumination light (EL) from a light source (21) and an image of a pattern (PA) of the mask (M) are defined. In an exposure apparatus (E) including a projection optical system (PL) that forms an image on a surface, the projection optical system (PL) is set to the numerical aperture (NA) measured by the imaging characteristic measuring apparatus (S). It is characterized by having been done.

The exposure method according to the present invention further comprises a light source (21)
The mask (M) is illuminated with the illumination light (EL) from the camera, and an image of the pattern (PA) of the mask (M) is formed on a predetermined surface in an exposure method. Is the numerical aperture (NA) measured by the imaging characteristic measuring method.
Is formed on a predetermined surface via a projection optical system (PL) having

According to the exposure apparatus and the exposure method of the present invention,
With the above-described imaging characteristic measuring device and the imaging characteristic measuring method, the numerical aperture (N) of the projection optical system (PL) is used as the imaging characteristic.
Since the exposure processing is performed using this projection optical system (PL) after measuring A), stable and accurate exposure processing can be performed. Then, by transferring the device pattern onto the substrate by the exposure method of the present invention,
Accurate devices can be manufactured.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of an imaging characteristic measuring method and an imaging characteristic measuring apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram for explaining an entire exposure apparatus E including an imaging characteristic measurement device (numerical aperture measurement device) S of the present invention, and FIG. 2 is a configuration for explaining the imaging characteristic measurement device S. FIG. 3 is an enlarged view of a main part for explaining a state where diffracted light DL is generated by irradiating the mask M with the exposure light EL.
FIG. 2 is a plan view for explaining a mask M.

As shown in FIG. 1, an exposure apparatus E provided with an imaging characteristic measuring apparatus (numerical aperture measuring apparatus) S illuminates a light beam from a light source 21 onto a mask M held on a mask stage MS. A system 2 and a blind portion 4 which is arranged in the illumination optical system 2 and adjusts the area of an opening K through which the illumination light for exposure (exposure light) EL passes to define an illumination range of the mask M by the exposure light EL. A projection optical system PL that projects an image of the pattern PA of the mask M illuminated with the exposure light EL onto the substrate W, a substrate holder 32 that holds the substrate W, and a substrate stage WS that supports the substrate holder 32; A detector A provided on the substrate stage WS and capable of detecting light information of light passing through the projection optical system PL, and a control device (arithmetic device) CONT for controlling the operation of the entire exposure apparatus E are provided.

The illumination optical system 2 includes a light source 21 such as a mercury lamp, an elliptical mirror 22 for condensing a light beam emitted from the light source 21, and an input for converting the condensed light beam into a substantially parallel light beam. A lens 23, an optical integrator 24 such as a fly-eye lens or a rod lens that adjusts a light beam output from the input lens 23 into a light beam having a substantially uniform illuminance distribution and converts the light beam into exposure light EL;
There is provided a reflecting mirror 25 for guiding the exposure light EL, which is emitted from the optical integrator 24 and whose illumination range is defined by the blind unit 4, to the mask M via the lens system 26. The blind part 4 is arranged on a plane conjugate with the pattern plane of the mask M.

The blind portion 4 adjusts the size of the opening K so that, out of the exposure light EL incident from the optical integrator 24, the passed exposure light EL
Only to the reflector 25. The exposure light EL defined by the opening K illuminates a specific area of the mask M held on the mask stage MS with substantially uniform illuminance via a reflecting mirror 25 and a lens system 26 such as a condenser lens.

The mask stage MS has a mask holder 30 for holding the mask M by vacuum suction. The mask holder 30 has an opening corresponding to the pattern area on the mask M where the pattern PA is formed, and is driven by a driving mechanism (not shown) in the X, Y, and θ directions (rotational directions around the Z axis). This allows the mask M to be positioned so that the center of the pattern area passes through the optical axis AX of the projection optical system PL. The drive mechanism of the mask holder 30 is configured using, for example, two sets of voice coil motors.

The projection optical system PL forms an image of a pattern existing in the illumination range of the mask M defined by the opening K by the exposure light EL on the substrate W, and forms the pattern on a specific area (shot area) of the substrate W. Exposure of the image. The projection optical system PL includes a plurality of optical members such as a lens and a reflector formed of a fluoride crystal such as fluorite or lithium fluoride. Also, on the pupil plane of the projection optical system PL,
An aperture stop AS for adjusting the amount of light reaching the image plane side (substrate stage WS side) is provided. This aperture stop A
An aperture stop driving device (adjustment device) 40 is connected to S, and the numerical aperture NA of the projection optical system PL can be adjusted by driving the aperture stop AS. The aperture stop driving device 40 is driven based on an instruction from a control device (arithmetic device) CONT.

The substrate stage WS has a substrate holder 32 for holding the substrate W by vacuum suction. The substrate stage WS is obtained by superposing a pair of blocks that can move in directions orthogonal to each other.
-It is movable in the horizontal direction along the Y plane. That is, the substrate W fixed to the substrate stage WS is
It is supported movably in the horizontal direction along the XY plane (in the direction perpendicular to the optical axis AX of the projection optical system PL). Note that the substrate W is supplied onto the substrate stage WS by a transport mechanism (not shown) after a photosensitive agent is applied to the surface (exposure processing surface) by a coater.

The position of the substrate stage WS in the XY directions is detected based on the reflected light of the laser light from the laser interferometer 33 from the movable mirror 34 on the substrate stage WS. This detected value is sent to the controller CONT, and the controller CONT
Is designed to control the position of the substrate stage WS while monitoring the detection values of these laser interferometers, for example, when stepping between shot areas. On the other hand, the position in the Z direction of the substrate W arranged in the projection area of the projection optical system PL is detected by a multipoint focus position detection system (not shown), which is one of the oblique incidence type focus detection systems. This detected value, that is, the position information of the substrate W in the Z direction is
Sent to ONT.

The control unit CONT controls the substrate W obtained by the laser interference system and the multipoint focus position detection system.
The substrate stage WS is driven via the substrate stage driving device 35 as a driving system while monitoring the position information in the XY direction and the Z direction of the projection optical system PL with respect to the pattern PA surface of the mask M and the substrate W surface. So that they are conjugate
In addition, the positioning operation of the substrate W in the XY direction, the Z direction, and the tilt direction is performed such that the image plane of the projection optical system PL and the substrate W coincide with each other. With the exposure light EL emitted from the illumination optical system 2 with the positioning performed in this manner, the mask M
When the region where the pattern PA is formed is illuminated with substantially uniform illuminance, an image of the pattern PA of the mask M is applied to the substrate W having a surface coated with a photoresist via the projection optical system PL.
Imaged on top.

Detector A provided on substrate stage WS
Detects the light information of the light that has passed through the projection optical system PL and reached the image plane, and is configured by a light amount sensor capable of detecting the light amount in the present embodiment. In addition,
The detector A can be configured by a light intensity sensor capable of detecting light intensity or an illuminance sensor capable of detecting illuminance. The detector A is provided movably at an image plane position on the substrate stage WS. And
The detection result of the detector A is output to a control device (arithmetic device) CO
Output to NT.

In the exposure apparatus E of this embodiment, the control unit CONT controls the substrate stage WS so that each shot area on the substrate W is sequentially positioned at the exposure position.
And an exposure operation of illuminating the mask M with the exposure light EL and transferring an image of a pattern formed on the mask M to a shot area on the substrate W in the positioning state. It has become.

As shown in FIGS. 2 and 3, the numerical aperture measuring device S is provided with a pattern PA that generates diffracted light DL (DLp, DLm) at a diffraction angle θ by being illuminated by illumination light (exposure light) EL. , A detector A capable of detecting the diffracted light DL that has passed through the projection optical system PL among the diffracted light DL generated by the pattern PA, and optical information of the diffracted light DL detected by the detector A. And a computing device (control device) CONT that performs a predetermined computation based on the computation.

As shown in FIG. 3, the pattern PA formed on the mask M has a dimensional ratio 1:
1 is a line-and-space pattern, and includes a transmission part (glass part) 50 that transmits the illuminated exposure light EL and a shielding part (chrome part) 51 that shields the illuminated exposure light EL. Further, the pattern PA includes a phase shift unit 52 that changes the phase of exposure light (illumination light) EL transmitted through the mask M. That is, the mask M in the present embodiment is a so-called phase shift mask, and the phase shift portions (shifters) 52 are provided every other glass portion 50. And the glass part 50
The phases of the exposure light EL transmitted through the phase shift section 52 are different from each other by approximately 180 °.

Therefore, by vertically irradiating the exposure light EL onto the pattern PA having the phase shift portion 52 whose phase can be made different by 180 °, the pattern PA
, The + 1st-order diffracted light DLp and the -1st-order diffracted light DLm are generated at the diffraction angle θ, and the 0th-order diffracted light DLz is canceled out and is not generated. The generated + 1st-order diffracted light DLp and −1st-order diffracted light DLm are incident on the projection optical system PL at an incident angle θ (that is, a diffraction angle). (Note that FIG. 3 shows only the -1st-order diffracted light DLm.)

In this case, assuming that the pattern PA formed at the pitch P is illuminated with the exposure light EL having the wavelength λ.
Exposure light EL transmitted through glass part 50 and phase shift part 52
The phase with the exposure light EL that passes through is inverted by 180 °, so that the positions e1 and e that are in phase with each other in FIG.
2 and e3, the distance between the position e2 and the position e3 is λ / 2.
Becomes On the other hand, the distance between the position e1 and the position e3 is the pitch P
Therefore, sin θ = λ / (2P) (1) holds.

As described above, the incident angle θ of the diffracted light DL incident on the projection optical system PL can be set based on the wavelength λ of the exposure light (illumination) EL and the pitch P of the pattern PA. According to the equation (1), when the pitch P is set to be large (wide), the incident angle θ with respect to the projection optical system PL can be reduced. On the other hand, when the pitch P is set to be small (narrow), , The incident angle θ can be increased.

By the way, the mask M is provided with a plurality of patterns PA having the above-described configuration, each having a different pitch P. That is, the mask M is
As shown in FIG. 4, different pitches P (P1 to P
9) A plurality of patterns PA (PA1 to PA) formed in
9) is provided. Therefore, each of these patterns PA
By irradiating the exposure light EL to the first to the PA9, the + 1st-order diffracted light DLp (DLp1 to DLp9) and the -1st-order diffracted light DL having different diffraction angles θ (θ1 to θ9), respectively
m (DLm1 to DLm9) can be generated. That is, each of these patterns PA1 to PA1
By irradiating the exposure light EL to the PA 9, different incident angles θ (θ 1 to
+ 1st-order diffracted light DLp (DLp1 to DLp) having θ9)
9) and −1st-order diffracted light DLm (DLm1 to DLm9) can be generated.

At this time, the pitch P1 of the pattern PA1 is the largest (widest) and the pitches P2, P3,
The pitch P9 is formed so as to become smaller (narrower) as it becomes...
Accordingly, the incident angle θ1 of the diffracted light DL generated from the pattern PA1 with respect to the projection optical system PL is the smallest, and the incident angles θ2, θ of the diffracted light DL generated as the patterns PA2, PA3,.
Are set so that the incident angle θ9 of the diffracted light DL generated from the pattern PA9 with respect to the projection optical system PL is maximized.

A method of measuring the numerical aperture NA of the projection optical system PL by the numerical aperture measuring device S having the above-described configuration will be described with reference to FIG.

For example, the exposure light EL is applied to the pattern PA1.
When the exposure light EL is illuminated on the pattern PA1, ± 1st-order diffracted lights DLp1 and DLm1 having a diffraction angle θ1 are generated from the pattern PA1. ± 1st order diffracted light DL generated from this pattern PA1
p1 and DLm1 enter the projection optical system PL at an incident angle θ1. At this time, the ± 1st-order diffracted lights DLp1, DLm
Since the incident angle θ1 with respect to the projection optical system PL is small, as shown in FIG. 5A, the ± first-order diffracted lights DLp1 and DLm1 incident on the projection optical system PL are
Without being shaken by the aperture stop AS provided on the pupil plane of
After passing through the projection optical system PL, the image plane side (substrate stage WS
Side) and is detected by the detector A.

When the exposure light EL is set to illuminate the pattern PA formed at a pitch P smaller than the pitch P1 formed at the pattern PA1, for example, the pattern PA3 formed at the pitch P3 is exposed to the exposure light EL. E
When L is illuminated, the diffraction angle θ3 is obtained from the pattern PA3.
± 1st-order diffracted lights DLp3 and DLm3 having
± 1st-order diffracted light DLp generated from this pattern PA3
3, DLm3 enters the projection optical system PL at an incident angle θ3. At this time, the ± 1st-order diffracted lights DLp3, DLm3
The angle of incidence θ3 with respect to the projection optical system PL is
The incident angle θ1 of the ± 1st-order diffracted lights DLp1 and DLm1 generated from A1 with respect to the projection optical system PL is larger. Therefore, as shown in FIG. 5 (c), the aperture stop AS is provided on the pupil plane of the projection optical system PL, cannot pass through the projection optical system PL, and is therefore located on the image plane side (substrate stage WS side).
And cannot be detected by the detector A.

Since the mask M is formed of a phase shift mask, no zero-order diffracted light DLz is generated.
Therefore, when the ± 1st-order diffracted lights DLp3, DLm3 are applied to the aperture stop AS, the diffracted lights (DLz, DLp, DLm) generated from the pattern PA3 cannot reach the image plane side at all, and the detector A emits light. Not detected.

As described above, the incident angles θ of the ± first-order diffracted lights DLp and DLm incident on the projection optical system PL change depending on the pitch P of the pattern PA illuminated with the exposure light EL,
In accordance with the incident angle θ, the light incident on the projection optical system PL
The first-order diffracted lights DLp and DLm may or may not reach the detector A side (image plane side). That is, when the incident angle θ is small, the diffracted light DL reaches the image plane side, and the incident angle θ
Is large, the diffracted light DL does not reach the image plane side.

Then, the diffracted light D with respect to the projection optical system PL
By changing the incident angle θ of L, FIG.
The critical incident angle θ that can pass through the projection optical system PL as shown in FIG. Since the incident angle θ with respect to the projection optical system PL can be adjusted by the pitch P of the pattern PA as described above, by adjusting this pitch P, the incident angle θ of the diffracted light DL with respect to the projection optical system PL Can be set arbitrarily.
Therefore, of the plurality of patterns PA, the diffracted light DL having an incident angle θ that can pass through the projection optical system PL
Is present at the critical pitch P that generates

By the way, the numerical aperture NA of the projection optical system PL
Denotes the numerical aperture from the object plane to the pupil plane of the projection optical system PL, and NA = nsin θ (2) Here, n is the refractive index of the medium, and θ is the angle (half-vertical angle) that is extended with respect to the radius of the pupil plane. Therefore, FIG.
As shown in (b), the critical incident angle θ (θmax) of the diffracted light DL with respect to the projection optical system PL that can pass through the projection optical system PL without being shaken by the aperture stop AS is (2).
The numerical aperture NA can be calculated from the equation (2).

Here, when the space is the atmosphere, the refractive index n
= 1, and from equations (1) and (2), NA = λ / (2P) (3) Therefore, a pitch P that generates θmax can be specified, and the numerical aperture NA can be obtained from the specified pitch P and Expression (3). That is, the numerical aperture NA can be calculated based on the pitch P of the pattern PA and the wavelength λ of the illumination light (exposure light) EL illuminating the pattern PA. Thus, the pattern PA having the critical pitch P for generating the diffracted light DL that can pass through the projection optical system PL is specified, and the specified pattern P
The numerical aperture NA can be determined based on A and the wavelength λ of the illumination light (exposure light) EL.

The numerical aperture NA of the projection optical system PL is measured by the procedure described above. Next, a specific procedure of a method of measuring a numerical aperture as an imaging characteristic measuring method of the present invention will be described. First, the mask M having the patterns PA1 to PA9 is loaded on the mask stage MS, and the detector A is arranged at a predetermined position (imaging position) on the image plane side of the projection optical system PL. Then, a predetermined process is performed so that any one of the plurality of patterns PA1 to PA9 is irradiated with the exposure light EL. For example, when irradiating the pattern PA1 with the exposure light EL, the blind unit 4 provided in the illumination optical system 2 is adjusted so that the exposure light EL from the light source 21 is exposed to the pattern P1.
It is set so that only A1 is illuminated. At this time, by driving the mask stage MS, the pattern PA to be illuminated with the exposure light EL (in this case, the pattern PA1) is moved to an arbitrary position in the illumination area (for example, the optical axis AX of the projection optical system PL).
Above).

After setting the pattern PA for illuminating the exposure light EL among the plurality of patterns PA1 to PA9, the exposure light EL is illuminated on the set pattern PA. When the exposure light EL is illuminated on the pattern PA1 having the pitch P1, as shown in FIG. 5A, the diffracted lights DLp1 and DLm generated from the pattern PA1.
1 enters the projection optical system PL at an incident angle θ1. At this time, since the incident angle θ1 is small, the diffracted light beams DLp1 and DLm1 incident on the projection optical system PL reach the image plane of the projection optical system PL without being cut by the aperture stop AS and are detected by the detector A
Is detected.

Next, by driving the mask stage MS, the pattern PA formed with the pitch P smaller than the pitch P1 is formed.
After arranging (for example, the pattern PA2) at an arbitrary position in the illumination area, the pattern PA is illuminated with the exposure light EL, and the amount of light on the image plane side of the projection optical system PL at this time is detected by the detector A. In this manner, the mask stage MS is sequentially driven so that the pitch P of the pattern PA illuminated with the exposure light EL is gradually reduced in a stepwise manner.
At an arbitrary position in the illumination area, and detects the amount of light on the image plane side of the projection optical system PL. At this time, since the pitch P of the pattern PA becomes smaller, the illumination range may be set by adjusting the blind portion 4 according to the size of the pattern PA. As the pitch P of the pattern PA illuminating the exposure light EL decreases, the incident angle θ with respect to the projection optical system PL increases, and the diffracted light D
L is the projection optical system PL as shown in FIG.
Of the aperture stop AS, and cannot reach the detector A. For example, it is assumed that the pattern at this time is PA3 and the incident angle of the diffracted light on the projection optical system PL is θ3.

The detection signal of the detector A is output to the arithmetic unit (control unit) CONT. Based on the detection result of the detector A, the arithmetic unit CONT calculates the diffracted lights DLp and DLm that can pass through the projection optical system PL as shown in the state of FIG.
A pattern PA having a critical pitch P that causes the pattern PA is specified.

In this case, the arithmetic unit CONT is arranged as shown in FIG.
The pattern that can generate the incident angle θmax (= θ2) as in the state of (b) is specified as PA2. Thus, the pattern PA illuminating the exposure light EL is sequentially changed,
At this time, the detector A detects whether or not the diffracted light DL that has entered the projection optical system PL has reached the image plane side of the projection optical system PL, whereby the projection as shown in FIG. The incident angle θmax of the diffracted light DL that can pass through the optical system PL with respect to the projection optical system PL, that is, the critical pitch P for generating the incident angle θmax (= θ2)
A pattern having (= P2) can be specified.

The arithmetic unit CONT calculates the numerical aperture NA of the projection optical system PL from equation (3) based on the specified critical pitch P (P2) and the wavelength λ of the illuminated exposure light EL. I do.

At this time, since the mask M is constituted by a phase shift mask as described above,
No second-order diffracted light DLz is generated. Therefore, in a state where the ± 1st-order diffracted lights DLp and DLm are blocked by the aperture stop AS and cannot reach the image plane side (the state of FIG. 5C), no light reaches the image plane side at all. , Detector A
Can sensitively and accurately detect whether or not the ± 1st-order diffracted lights DLp and DLm are shaken by the aperture stop AS without being affected by the 0th-order diffracted light DLz.

Here, as a specific example, for example, the exposure light E
When a KrF excimer laser having a wavelength λ = 248 nm is used as L and the critical pitch P of the pattern in which the detector A can detect the diffracted light DL is 182 nm, the arithmetic unit CONT is obtained from the equation (3). , The numerical aperture NA of the projection optical system PL is calculated to be 0.681. Similarly,
When an i-line of a mercury lamp having a wavelength of λ = 365 nm is used as the exposure light EL, the detector A diffracts the light D.
If the critical pitch P of the pattern in which L can be detected is 290 nm, the arithmetic unit CONT calculates from the equation (3) that the numerical aperture NA of the projection optical system PL is 0.629.

After calculating the numerical aperture NA as described above, the control device CONT controls the aperture stop driving device based on the calculated numerical aperture NA so that the projection optical system PL has a desired numerical aperture NA. 40 is driven to adjust the aperture stop AS. After adjusting the numerical aperture NA by driving the aperture stop AS, the mask M for numerical aperture measurement is unloaded from the mask stage MS, and a mask having a predetermined pattern to be transferred onto the substrate W is placed on the mask stage. Load to MS. The illumination optical system 2 is provided on this mask.
The substrate W is illuminated with the exposure light EL to form an image of a predetermined pattern formed on the mask on the substrate (predetermined surface) W via the projection optical system PL whose numerical aperture NA is measured. An image of a predetermined pattern of the mask is transferred.

As described above, a plurality of lights (diffractive light DL) are respectively incident on the projection optical system PL at different incident angles θ, and the amounts of the respective lights passing through the projection optical system PL are detected. A change in the amount of light according to the incident angle θ can be detected. Then, based on this change in the amount of light, the critical incident angle θ that can pass through the projection optical system PL
Can be requested. Then, the numerical aperture NA of the projection optical system PL can be obtained based on the obtained incident angle θ. As described above, the projection optical system PL has a simple configuration in which a plurality of lights are made to enter the projection optical system PL at different incident angles θ and the amount of light that has passed through the projection optical system PL is detected. Can be obtained.

In this case, in order to detect a change in the amount of light, it is necessary to cause light to enter the projection optical system PL at at least two different incident angles θ. That is, in the above embodiment, the diffracted light DLp at the angle θ1 (first incident angle)
1. DLm1 (first light) is incident on the projection optical system PL, and the diffracted lights DLp1, Dp that have passed through the projection optical system PL.
Lm1 is detected, and the angle θ different from the angle θ1 is detected.
In step 3, the diffracted lights DLp3 and DLm3 (second light) are made incident on the projection optical system PL, and the light quantities of the diffracted lights DLp3 and DLm3 that have passed through the projection optical system PL are detected, whereby the light quantity changes at this time are obtained. Based on the change in the amount of light between the diffracted light DL1 and the diffracted light DL3, the critical incident angle θ2
Can be requested. Then, based on the obtained incident angle θ2, the numerical aperture NA of the projection optical system PL can be accurately calculated.

At this time, the diffracted lights DLp1 and DLm having the predetermined incident angles θ1 and θ3 with respect to the projection optical system PL.
1 and DLp3 and DLm3, a mask M on which a pattern PA1 formed at a pitch P1 and a pattern PA3 formed at a pitch P3 different from the pitch P1 are arranged, and exposure light is applied to each of the patterns PA1 and PA3. (Illumination light) By illuminating the EL, it can be easily and stably generated. Then, by changing only the pitch P, the incident angle θ of the diffracted light DL with respect to the projection optical system PL can be easily adjusted.

Since the mask M is a phase shift mask, of the diffracted light DL generated from each pattern PA,
Since the zero-order diffracted light DLz is not generated, the detector A does not detect the amount of light when the incident angle θ of the generated ± first-order diffracted lights DLp and DLm with respect to the projection optical system PL is increased and the light is shaken by the aperture stop AS. As described above, when the pitch P of the pattern PA is changed, the amount of light detected by the detector A changes stepwise, so that the detector A is not affected by the 0th-order diffracted light DLz and is not affected by the ± 1st-order diffracted light. DL
It is possible to sensitively and accurately detect a change in the light amount of p and DLm. Therefore, accurate and stable numerical aperture measurement can be realized as the measurement of the imaging characteristics.

A plurality of patterns PA formed at different pitches P are formed on a mask M, each pattern PA is illuminated with exposure light EL, and the diffracted light DL generated in each pattern PA is projected. Optical system P
L, of the diffracted light DL generated in each pattern PA, the diffracted light DL that can pass through the projection optical system PL.
The numerical aperture NA can be obtained with higher accuracy by specifying the pattern PA having the critical pitch P at which the pattern PA is generated. That is, as described above, the numerical aperture NA
Can be obtained by irradiating each of the patterns PA formed with at least two different pitches P with the exposure light EL. However, it is necessary to finely change the pitch P in accordance with the accuracy of the desired numerical aperture NA. Thus, the critical pitch P (critical incident angle θmax) can be obtained with high accuracy. In other words, in the above-described embodiment, when it is desired to obtain the numerical aperture NA with high accuracy, a large number (for example, 10 patterns) of the patterns PA having different pitches P are provided stepwise between the patterns PA1 and PA3. , The numerical aperture NA can be determined with high accuracy. On the other hand, if the accuracy of the numerical aperture NA to be obtained is low to some extent, there is a gap between the pattern PA1 and the pattern PA3.
A small number (or no patterns) of the pattern PA in which the pitch P varies stepwise may be used. In this case, the numerical aperture NA
Is obtained by using a mask M on which at least a pattern PA1 (first pattern) formed at a predetermined pitch P1 and a pattern PA3 (second pattern) formed at a pitch P3 different from the pitch P1 are formed. It is a configuration that can be used.

Since the 0th-order diffracted light DLz is not generated by using the phase shift mask, the detector A can detect a change in the amount of light sensitively. ), The detector A can detect a change in the amount of light according to a change in the incident angle θ of the diffracted light DL generated in the pattern PA with respect to the projection optical system PL. In this case, even when the ± 1st-order diffracted lights DLp and DLm are applied to the aperture stop AS, the 0th-order diffracted light DLz is detected by the detector A. Although the change cannot be detected sensitively, it is possible to detect a change in the amount of light.

As shown in FIG. 6A, the patterns PA1 to PA9 formed at different pitches P1 to P9 are arranged in a predetermined area AR, and the patterns PA1 to PA9 formed in this area AR are arranged. As one combination, as shown in FIG. 6B, a plurality (9) of masks M formed in a plate shape may be provided in the plate surface direction.

Area A provided with patterns PA1 to PA9
Since R is provided at a plurality of positions in the plate surface direction of the mask M, the numerical aperture NA in each area AR can be measured using the patterns PA1 to PA9 in each area AR. In this case, the distribution (variation) of the numerical aperture NA of the projection optical system PL at a plurality of positions in the exposure area can be measured, and the imaging characteristics of the projection optical system PL can be adjusted based on the measurement result. it can.

Second Embodiment Next, a second embodiment of the imaging characteristic measuring method and the imaging characteristic measuring apparatus of the present invention will be described with reference to FIG. Here, for the same or equivalent components as in the first embodiment described above,
The same reference numerals are used, and the description thereof will be simplified or omitted.

In FIG. 7, a mask M2 has a line-and-space consisting of a transmission portion (glass portion) 50 for transmitting the illuminated exposure light EL and a shielding portion (chrome portion) 51 for shielding the irradiated exposure light EL. The pattern includes a pattern having a dimensional ratio set to 1: 1. And
The mask M2 according to the present embodiment has a configuration including a normal chrome pattern that does not change the phase of the transmitted exposure light EL.

Therefore, by irradiating the pattern formed on the mask M2 with the exposure light EL, the zero-order diffracted light D
Lz and ± first-order diffracted lights DLp and DLm are generated.

In order to measure the numerical aperture NA of the projection optical system PL as an imaging characteristic by using the imaging characteristic measuring device (numerical aperture measuring device) S2 having the configuration described above, first, the mask M2 Is loaded on the mask stage MS. Next, the mask M2 is illuminated with illumination light (exposure light) EL from a direction inclined with respect to the optical axis AX of the projection optical system PL.

At this time, from the pattern PA formed on the mask M2, the 0th-order diffracted light DLz and the ± 1st-order diffracted light DL
Although p and DLm are generated, the exposure light E
By adjusting the incident angle T of L, any one of the ± first-order diffracted lights DLp and DLm and the zero-order diffracted light DLz out of the generated diffracted light DL have a predetermined incident angle θ with respect to the projection optical system PL. Incident.

In this case, the projection optical system P of the 0th-order diffracted light DLz and the + 1st-order diffracted light DLp (or the -1st-order diffracted light DLm) is used.
The incident angle T of the exposure light EL with respect to the mask M2 is set such that the incident angle θ with respect to L is symmetric with respect to the optical axis AX of the projection optical system PL.

By irradiating the mask M2 with the exposure light (illumination light) EL from the oblique direction, the mask M2 is illuminated.
Of the diffracted light DL generated from the pattern PA formed on the first and second order diffracted lights DLz, DLp and DLm
Is incident on the projection optical system PL at a predetermined incident angle (first incident angle) θ1. Then, the diffracted light DL that has passed through the projection optical system PL
Is detected by the detector A.

Next, the incident angle θ2 different from the angle θ1
So that the 0th-order diffracted light DLz and the + 1st-order diffracted light DLp (or the -1st-order diffracted light DLm) enter the projection optical system PL,
The exposure light EL is illuminated at a predetermined angle with respect to a pattern PA2 having a predetermined pitch P2. Then, the detector A detects the diffracted light DL incident at the incident angle θ2 and passing through the projection optical system PL.

Thus, similarly to the first embodiment, the diffracted light DL is made incident on the projection optical system PL at different incident angles θ1 and θ2, and the detector A detects the diffracted light DL passing through the projection optical system PL. The aperture NA of the projection optical system PL is calculated based on the detected light information.

As described above, even if the mask M2 having the line and space pattern is irradiated with the exposure light (illumination light) EL from the oblique direction, that is, the so-called deformed illumination, the predetermined incidence on the projection optical system PL is achieved. It is possible to generate two luminous fluxes including the 0th-order diffracted light DLz and the + 1st-order diffracted light DLp (or the -1st-order diffracted light DLm) incident at an angle θ.

Also in this embodiment, the light incident on the projection optical system PL includes the 0th-order diffracted light DLz and the ± 1st-order diffracted light DL
Since any one of p and DLm (that is, two light beams), the diffracted light DL incident on the projection optical system PL with the change of the incident angle θ with respect to the projection optical system PL is projected onto the aperture stop AS, the projection optical system No light reaches the image plane side of the system PL. Accordingly, the detector A can sensitively and accurately detect a change in the amount of light on the image plane side of the projection optical system PL. Therefore, accurate and stable numerical aperture measurement can be realized.

<< Third Embodiment >> Next, a third embodiment of the imaging characteristic measuring method and the imaging characteristic measuring apparatus of the present invention will be described with reference to FIG. Here, the same reference numerals are used for the same or equivalent components as those of the above-described first and second embodiments, and the description thereof will be simplified or omitted.

In FIG. 8, a mask M3 has a line-and-space consisting of a transmission part (glass part) 50 for transmitting the illuminated exposure light EL and a shielding part (chrome part) 51 for shielding the irradiated exposure light EL. The pattern includes a pattern having a dimensional ratio set to 1: 1. And
The mask M3 according to the present embodiment is similar to the mask according to the second embodiment.
It has a configuration including a normal chrome pattern that does not change the phase of the transmitted exposure light EL. Therefore, by irradiating the pattern formed on the mask M3 with the exposure light EL, the 0th-order diffracted light DLz and the ± 1st-order diffracted lights DLp and Dp are emitted.
Lm occurs.

On the pupil plane on the optical axis AX of the projection optical system PL,
A light shielding unit (pupil plane filter) 60 is provided. The light shielding portion 60 is for restricting the zero-order diffracted light DLz from reaching the image plane side (the substrate stage WS side) of the projection optical system PL, and is arranged on the pupil plane of the projection optical system PL. As a result, light passing near the optical axis AX (0th-order diffracted light D
Lz) is shielded from light.

The projection optical system P is formed by the imaging characteristic measuring device (numerical aperture measuring device) S3 having the configuration as described above.
A method for measuring the numerical aperture of L will be described. First, the mask M3 is loaded on the mask stage MS. Then, exposure light (illumination light) EL is vertically illuminated on the mask M3.

By irradiating the pattern PA formed on the mask M3 with the exposure light EL, the pattern M becomes zero from the mask M3.
First-order diffracted light DLz and ± first-order diffracted lights DLp and DLm are generated. The 0th-order diffracted light DLz is transmitted to the projection optical system PL.
Incident perpendicularly (in the direction along the optical axis AX) to ± 1
The next-order diffracted lights DLp and DLm enter the projection optical system PL at a predetermined incident angle θ. That is, in this case, the projection optical system P
L receives three diffracted lights (light fluxes) DL.

Of the diffracted light DL incident on the projection optical system PL, the zero-order diffracted light DLz is shielded by the light shielding unit 60,
It does not reach the image plane side (substrate stage WS side) of projection optical system PL. Therefore, only the ± 1st-order diffracted lights DLp and DLm can reach the substrate stage WS side.

The ± 1st-order diffracted lights DLp and DLm generated from the pattern PA and incident at an incident angle θ reach the image plane side of the projection optical system PL or the aperture stop according to the pitch P of the pattern PA. I'm kicked by AS. Thus, similarly to the first and second embodiments, the plurality of diffracted lights DL are made incident on the projection optical system PL at different incident angles θ, and the respective light amounts of the diffracted lights DL passing through the projection optical system PL are reduced. The change in light quantity is detected to detect, and the numerical aperture NA of the projection optical system PL is calculated based on the change in light quantity.

As described above, by arranging the light shielding portion 60 on the pupil plane of the projection optical system PL, even when the exposure light EL is vertically illuminated on the mask M3 having a normal line and space pattern. , Projection optical system P
Light that can reach the image plane side of L is ± 1st-order diffracted light DLp, D
There are only two light beams of Lm. Therefore, when the incident angles θ of the ± first-order diffracted lights DLp and DLm generated from the pattern PA are increased and are shifted to the aperture stop AS, no light reaches the image plane side of the projection optical system PL. , Second
As in the embodiment, the amount of light detected by the detector A changes stepwise. Therefore, since the detector A can sensitively and accurately detect a change in the amount of light on the image plane side of the projection optical system PL, accurate and stable numerical aperture measurement can be realized.

In each of the above embodiments, the illumination light for illuminating the pattern PA formed on the mask M is used as the exposure light EL. However, the illumination light may be any light as long as it has a predetermined wavelength. Light can be used.

In each of the above embodiments, the projection optical system P
The detection of the optical information of the diffracted light DL passing through L is performed using the detector A composed of a light amount sensor, but when the illumination light for the mask M is the exposure light EL, the projection optical system PL is used.
It is also possible to adopt a configuration in which a photosensitive substrate is arranged on the image plane side of the above, and whether or not a projected image of the pattern PA is projected on this photosensitive substrate. In this case, the pattern P
After projecting the image of A, development processing is performed, and by detecting the shape of the formed pattern using a shape measuring device such as an SEM, it is determined whether or not the projected image of the pattern PA is projected on the photosensitive substrate. Can be detected.

In each of the above embodiments, the pattern PA is sequentially arranged at an arbitrary position in the illumination area by driving the mask stage MS. However, a plurality of patterns may be simultaneously illuminated. Further, a CCD capable of two-dimensional position detection may be used as the detector A. By doing so, the plurality of patterns PA (P) reaching the image plane of the projection optical system PL
A1 to PA9) can be simultaneously detected.

In each of the above embodiments, the pattern PA
Is changed, and the critical pitch P is specified, and the numerical aperture NA is obtained based on the specified pitch P and the wavelength λ of the illumination light illuminated at that time. The wavelength λ of the illumination light to be illuminated with the pitch P fixed is changed, a critical wavelength λ at which light reaches the image plane side is specified, and based on the specified wavelength λ and the pitch P at that time. It is also possible to adopt a configuration for obtaining the numerical aperture NA.

The substrate W according to the present invention is not limited to a semiconductor wafer for a semiconductor device, but may be a glass plate for a liquid crystal display device or a ceramic wafer for a thin-film magnetic head.

The exposing apparatus E exposes the pattern of the mask M while keeping the mask M and the substrate W stationary.
Not only the step-and-repeat type exposure apparatus (stepper) for sequentially moving the mask M, but also the step-and-scan type scanning for exposing the pattern of the mask M onto the substrate W by synchronously moving the mask M and the substrate W. It can also be applied to a mold exposure apparatus (scanning stepper).

The types of the exposure apparatus E include not only those for manufacturing semiconductors but also those for manufacturing liquid crystal display devices, thin-film magnetic heads, imaging devices (CCD), masks M, and the like. Is also widely applicable.

As the light source 21 of the illumination optical system 2, bright lines (g-line (436 nm), h-line (404.7 nm), i-line (365 nm)) generated from a mercury lamp, KrF excimer laser (248 nm), ArF Not only excimer laser (193 nm) and F2 laser (157 nm) but also charged particle beams such as X-rays and electron beams can be used. For example, when an electron beam is used, a thermionic emission type lanthanum hexaborite (LaB6) is used as an electron gun.
) And tantalum (Ta) can be used. Also,
A high frequency such as a YAG laser or a semiconductor laser may be used.

The magnification of the projection optical system PL may be not only a reduction system but also an equal magnification system or an enlargement system.

Further, as the projection optical system PL, when far ultraviolet rays such as an excimer laser are used, a material which transmits far ultraviolet rays such as quartz or fluorite is used as a glass material. When an F2 laser is used, a catadioptric system or a refracting system is used. System optics,
When an electron beam is used, an electron optical system including an electron lens and a deflector may be used as the optical system. It goes without saying that the optical path through which the electron beam passes is in a vacuum state.

When a linear motor is used for the substrate stage WS or the mask stage MS, either an air levitation type using an air bearing or a magnetic levitation type using Lorentz force or reactance force may be used. Further, the substrate stage WS and the mask stage MS may be of a type that moves along a guide, or may be of a guideless type without a guide.

When a plane motor is used as the stage driving device, one of the magnet unit (permanent magnet) and the armature unit is connected to the stage, and the other of the magnet unit and the armature unit is connected to the stage moving surface side. (Base).

The reaction force generated by the movement of the substrate stage WS may be mechanically released to the floor (ground) by using a frame member, as described in JP-A-8-166475. The present invention is also applicable to an exposure apparatus having such a structure.

The reaction force generated by the movement of the mask stage MS may be mechanically released to the floor (ground) using a frame member as described in Japanese Patent Application Laid-Open No. 8-330224. The present invention is also applicable to an exposure apparatus having such a structure.

As described above, the exposure apparatus according to the embodiment of the present invention converts various subsystems including the components described in the claims of the present application into predetermined mechanical accuracy, electrical accuracy,
It is manufactured by assembling to maintain optical accuracy. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electric systems to ensure these various accuracy Are adjusted to achieve electrical accuracy. The process of assembling the various subsystems into the exposure apparatus includes mechanical connection, wiring connection of an electric circuit, and piping connection of a pneumatic circuit between the various subsystems. It goes without saying that there is an assembling process for each subsystem before the assembling process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed, and various precisions of the entire exposure apparatus are secured. It is desirable that the exposure apparatus be manufactured in a clean room in which the temperature, cleanliness, and the like are controlled.

As shown in FIG. 9, in the semiconductor device, a step 201 for designing the function and performance of the device, and a step 20 for manufacturing a mask based on the design step, are performed.
2. Step 203 of manufacturing a substrate (wafer, glass plate) serving as a base material of a device; substrate processing step 204 of exposing a device pattern of a mask onto a substrate (wafer) by the exposure apparatus of the above-described embodiment; Dicing process, bonding process,
(Including a package process) 205, an inspection step 206, and the like.

[0097]

According to the present invention, the imaging characteristic measuring method and the imaging characteristic measuring apparatus, the exposure method, the exposure apparatus, and the device manufacturing method have the following effects. According to the present invention, the first light and the second light are respectively incident on the projection optical system at different incident angles, and the optical information of the first and second lights passing through the projection optical system is detected. Based on this optical information, the numerical aperture NA of the optical system PL can be obtained as the imaging characteristic. As described above, the numerical aperture of the optical system can be accurately determined with a simple configuration in which the first and second lights are made to enter the optical system at different incident angles and the optical information of the light passing through the optical system is detected. You can ask.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an exposure apparatus provided with an imaging characteristic measuring apparatus of the present invention.

FIG. 2 is a configuration diagram for explaining a first embodiment of an imaging characteristic measuring method and an imaging characteristic measuring device of the present invention.

FIG. 3 is an enlarged sectional view of a main part for explaining the vicinity of a mask illuminated with illumination light in FIG. 2;

FIG. 4 is a plan view for explaining a pattern formed on a mask.

FIG. 5 is a diagram for explaining diffracted light generated when illumination light is illuminated on each pattern having a different pitch.

FIGS. 6A and 6B are diagrams for explaining a pattern formed on a mask, wherein FIG. 6A is an enlarged plan view for explaining a plurality of patterns formed in a predetermined area, and FIG.
Is a plan view of the entire mask.

FIG. 7 is a configuration diagram for explaining a second embodiment of the imaging characteristic measuring method and the imaging characteristic measuring apparatus of the present invention.

FIG. 8 is a configuration diagram for explaining a third embodiment of the imaging characteristic measuring method and the imaging characteristic measuring apparatus of the present invention.

FIG. 9 is a flowchart illustrating an example of a manufacturing process of a semiconductor device.

[Explanation of symbols]

2 Illumination optical system 21 Light source 40 Aperture stop driving device (adjustment device) 50 Transmitting portion (glass portion) 51 Shielding portion (chrome portion) 52 Phase shift portion 60 Shielding portion (pupil surface filter) A Detector AS Aperture stop AX Optical axis CONT arithmetic unit (control unit) E exposure unit EL exposure light (illumination light) DL diffracted light (first light, second light) DLz 0th-order diffracted light (first light, second light) DLp + 1st-order diffracted light (First light, second light) DLm -1st-order diffracted light (first light, second light) M, M2, M3 Mask MS Mask stage P (P1 to P9) Pitch PA (PA1 to PA9) Pattern PL (projection) optical system S, S2, S3 Imaging characteristic measuring device (numerical aperture measuring device) W substrate WS substrate stage θ (θ1 to θ9) Incident angle

Claims (12)

[Claims] 1. An imaging characteristic measuring method for measuring an imaging characteristic of an optical system, wherein a first light is incident on the optical system at a first incident angle, and the first light having passed through the optical system is provided. Detecting optical information of the second light at an incident angle different from the first incident angle into the optical system, detecting optical information of the second light passing through the optical system, An imaging characteristic measuring method, wherein a numerical aperture of the optical system is calculated as the imaging characteristic based on optical information of a first light and optical information of the second light. 2. The imaging characteristic measuring method according to claim 1, wherein a first pitch formed on the object plane side of the optical system at a predetermined pitch.
Disposing a mask on which at least a pattern and a second pattern formed at a pitch different from the predetermined pitch are formed, wherein the first light is generated by illuminating the first pattern; 2. The imaging characteristic measuring method according to claim 1, wherein the second light is generated by illuminating the second pattern. 3. The imaging characteristic measuring method according to claim 2, wherein the first and second patterns formed on the mask are:
A phase shift unit that changes a phase of the illumination light transmitted through the mask; the first light incident on the optical system is ± 1st-order diffracted light generated from the first pattern; The method according to claim 1, wherein the incident second light is ± 1st-order diffracted light generated from the second pattern. 4. The imaging characteristic measuring method according to claim 2, wherein the mask is illuminated from a direction inclined with respect to an optical axis of the optical system, and the first light incident on the optical system is One of the ± 1st-order diffracted lights generated from the first pattern and the 0th-order diffracted light generated from the first pattern, and the second light incident on the optical system is ± 1 generated from the second pattern. An imaging characteristic measuring method, wherein one of the first-order diffracted lights and the zero-order diffracted light generated from the second pattern. 5. The imaging characteristic measuring method according to claim 2, wherein the first light is 0-order diffracted light and ± 1st-order diffracted light generated from the first pattern, and the second light is An imaging characteristic measuring method, wherein the 0th-order diffracted light and the ± 1st-order diffracted light generated from the second pattern are each limited to reach the image plane of the optical system. . 6. The imaging characteristic measuring method according to claim 2, wherein the mask includes a first pattern pitch and a second pattern pitch.
A plurality of patterns formed at a pitch different from the pattern pitch, irradiating the mask with illumination light of a predetermined wavelength, and by irradiating the illumination light, the first pattern and the second pattern; The light generated in each of the patterns is incident on the optical system, and among the light generated in the plurality of patterns, a pattern having a critical pitch that generates light that can pass through the optical system is specified. And calculating the numerical aperture based on the determined pattern and the predetermined wavelength of the illumination light. 7. The imaging characteristic measuring method according to claim 1, wherein the light is used as exposure illumination light, and a projected image is formed on a photosensitive substrate disposed on an image plane of the optical system. An imaging characteristic measuring method, which detects whether or not the image has been projected. 8. An imaging characteristic measuring apparatus for measuring an imaging characteristic of an optical system, comprising: a first light having a first incident angle; and a second light having an incident angle different from the first incident angle. A mask that generates light, a detector that detects the first light that has passed through the optical system, and the second light that has passed through the optical system, and a first detector that is detected by the detector. An imaging device for calculating the numerical aperture of the optical system as the imaging characteristic based on the optical information of the light and the optical information of the second light. 9. The imaging characteristic measuring apparatus according to claim 8, further comprising: an adjusting device that adjusts a numerical aperture of the optical system based on the numerical aperture calculated by the arithmetic device. Imaging characteristic measuring device. 10. An exposure apparatus comprising: an illumination optical system that illuminates a mask with illumination light from a light source; and a projection optical system that forms an image of a pattern of the mask on a predetermined surface, wherein the projection optical system comprises: An exposure apparatus, wherein the numerical aperture is set to a numerical aperture measured by the imaging characteristic measuring apparatus according to claim 8 or 9. 11. A mask is illuminated with illumination light from a light source,
In an exposure method for forming an image of a pattern of the mask on a predetermined surface, the image of the pattern of the mask is measured by the imaging characteristic measuring method according to any one of claims 1 to 8. An exposure method, wherein an image is formed on the predetermined surface via a projection optical system having a numerical aperture. 12. A method for manufacturing a device, comprising transferring a device pattern onto a substrate by the exposure method according to claim 11.