JP3243818B2 - Projection exposure apparatus and method, and element manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type exposure apparatus,
In particular, the present invention relates to changing the imaging characteristics of a projection optical system of a projection type exposure apparatus for manufacturing a semiconductor integrated circuit or a liquid crystal device.

[0002]

2. Description of the Related Art Conventionally, this type of apparatus has a Fourier transform plane (hereinafter referred to as a pupil plane of the illumination optical system) in an illumination optical system with respect to a plane on which a pattern on a reticle exists, or a plane in the vicinity thereof. The reticle is illuminated by restricting the illumination light flux to a substantially circular (or rectangular) centered on the optical axis of the illumination optical system (hereinafter referred to as normal illumination). As described above, in the normal illumination, the intensity of the illumination light from each direction within the range of the incident angle of the illumination light to the reticle pattern (the numerical aperture of the illumination light flux) is substantially uniform, and the numerical aperture of the illumination light flux and the projection The ratio (σ value) of the optical system to the reticle-side numerical aperture is 0.5 to 0.5.
It was about 7. In normal illumination, assuming that the exposure wavelength is λ and the numerical aperture on the wafer side of the projection optical system is NA _W , the resolution is given by approximately 0.7 × λ / NA _W and the depth of focus is ± λ / 2.
(NA) ² given.

In ordinary illumination, in order to expose a finer pattern, it is necessary to use an exposure light source having a shorter wavelength or a projection optical system having a larger numerical aperture. However, it is difficult at present at present to shorten the wavelength of the exposure light source (for example, 200 nm or less) because of the absence of a suitable optical material and the lack of a stable light source capable of obtaining a large amount of light. Also,
When the numerical aperture of the projection optical system is increased, the depth of focus is inversely proportional to the square of the numerical aperture, so that it has been difficult to realize an optical system that achieves high resolution and a sufficient depth of focus.

Therefore, a phase shifter provided with a phase shifter for shifting the phase of the transmitted light from a specific portion of the reticle circuit pattern by π (rad) with respect to the transmitted light from another transmitting portion. The use of reticles has also been proposed. A phase shift reticle is disclosed, for example, in Japanese Patent Publication No. Sho 62-50811. Use of this phase shift reticle has the effect of improving resolution.

Recently, annular illumination or reticle patterns that shield only the central portion of the illuminating light beam on the reticle pattern within the incident angle range (restrict the light quantity distribution on the pupil plane of the illumination optical system into an annular shape) A specific (discrete) illumination light beam is incident on the illumination optical system from a plurality of directions (the light amount distribution on the pupil plane of the illumination optical system is maximized at a plurality of discrete positions decentered from the optical axis of the illumination optical system) A modified light source (which limits the luminous flux to have a value) has been proposed. When the annular illumination or the deformed light source is used, the resolution and the depth of focus of the projection optical system can be improved, though the light amount loss and the illuminance uniformity are deteriorated.

Here, in manufacturing a semiconductor integrated circuit, high resolution is naturally required, but the depth of focus (focus margin) is also an extremely important factor. On the other hand, a method of increasing the depth of focus by giving a specific aberration (particularly, spherical aberration) to a projection optical system without using the above-mentioned deformed light source or the like is disclosed in Japanese Patent Application Laid-Open No. HEI 2 (1994) -209873.
No. 2,344,411. This utilizes the fact that the photosensitive material (photoresist) on the wafer has a thickness of about 1 μm, and the depth of focus is increased although the contrast is slightly lowered.

[0007]

In the prior art as described above, the aberration of the projection optical system, particularly the spherical aberration, is fixed at the time of manufacture or adjustment and cannot be easily changed thereafter. Was. Further, when the above-described annular illumination, deformed light source, and phase shift reticle are applied to a projection optical system having a predetermined spherical aberration in accordance with normal illumination to increase the depth of focus, the predetermined spherical aberration is reduced. Adversely affect. That is, when the annular illumination, the deformed light source, and the phase shift reticle are used, the spherical aberration causes a reduction in the depth of focus and a change in the focus position due to the line width (pitch). For this reason, there is a problem that the effective depth of focus is reduced as compared with a case where a predetermined spherical aberration is not provided.

[0008] Even in an optical system having no particular spherical aberration, distortion or the like may occur with a change in illumination conditions. The present invention has been made in view of the above problems, and can be used by switching between normal illumination and deformed light source or annular illumination, and phase shift reticle, and a projection type that maximizes the depth of focus under each illumination condition. It is intended to realize an exposure apparatus.

[0009]

According to the projection exposure apparatus of the present invention, a predetermined plane (a pupil plane of the illumination optical system) substantially having a Fourier transform relationship with the pattern surface of the mask (R) in the illumination optical system. ) Is variable, and when at least a part of a pattern to be transferred onto the photosensitive substrate (W) has periodicity, an incident angle (ψ) corresponding to the fineness (pitch P) of the pattern. In (2), the center is located at a position decentered from the optical axis of the illumination optical system on a predetermined surface so that the illumination light is incident on the mask while being inclined with respect to the optical axis (AX) of the illumination optical system. The distance from the optical axis of the illumination optical system (α,
changing means (for example, polyhedral prisms 60a, 60a) for increasing the light amount distribution in a plurality of regions where β) is determined to be substantially equal
b, a plurality of optical integrator systems, drive system 54, etc.) and adjustment means (for example, drive element 25,
27, 29, 57, 58 and control unit 53
Etc.).

[0010]

[Function] Switching between normal illumination and annular illumination, switching between normal illumination and deformed light source, switching between normal illumination (normal reticle) and phase shift reticle, and switching between annular illumination and deformed light source are possible. By moving the lens element of the projection optical system according to the above, distortion and spherical aberration can be changed, and the optimum imaging characteristics of the projection optical system can be obtained according to each illumination condition.

[0011]

FIG. 1 is a plan view showing a schematic configuration of a projection exposure apparatus according to one embodiment of the present invention. In FIG. 1, an extra-high pressure mercury lamp 1 generates illumination light (i-line or the like) IL in a wavelength range such that the resist layer is exposed. Illumination light source for exposure 1
For example, a laser light source such as a KrF or ArF excimer laser, or a harmonic such as a metal vapor laser or a YAG laser may be used in addition to an emission line such as a mercury lamp. The illumination light IL is reflected by the elliptical mirror 2 and condensed at its second focal point f ₀ , and then enters the optical integrator block 6 via the mirror 3 and the relay lens 4.

FIG. 1 shows a case where two types of optical integrator systems are included in the optical integrator block 6, and these two types of optical integrator systems are interchangeable. The first optical integrator system includes the input lens 5 and the fly-eye lens 7, and the light quantity distribution on the exit-side surface 7a of the fly-eye lens 7 is substantially uniform within a circular area in a plane perpendicular to the optical axis AX. Distribution (normal illumination). The exit surface 7a of the fly-eye lens 7 has an optical Fourier transform relationship with the reticle pattern of the reticle R.
Therefore, the light amount distribution on the exit surface 7a of the fly-eye lens 7 corresponds to the distribution of the illumination light amount within the incident angle range on the reticle pattern surface.

The second optical integrator system comprises a polyhedral prism 60, an input lens 61, and two fly-eye lenses 62A and 62B as an input optical system. The polygonal prism 6 is composed of the V-shaped concave prism 60a and the V-shaped concave prism 60a.
Illumination light I from the light source 1
L is divided into two. Each light beam from the polygonal prism 60 enters the fly-eye lenses 62A and 62B via the input lenses 61a and 61b. The exit surfaces 62a, 62b of the fly-eye lenses 62A, 62B also have an optical Fourier transform relationship with the reticle pattern of the reticle R. In this way, the illuminating light flux passing through the pupil plane of the illumination optical system, or its conjugate plane, or a plane near the pupil plane, has at least two centers having centers at positions decentered by a predetermined amount from the optical axis AX of the illumination optical system. By defining the local area, the illumination light beam applied to the reticle R is tilted in a predetermined direction by an angle corresponding to the fineness of the reticle pattern (hereinafter, simply referred to as a multiple tilt illumination method).

In FIG. 1, the first optical integrator system is arranged in the optical path, and shows a state of normal illumination. The exit surface (reticle side focal plane) 7a vicinity of the fly eye lens 7, the aperture stop 8 for varying the numerical aperture NA _IL of the illumination optical system is disposed. The illumination light IL emitted from the fly-eye lens 7 is transmitted to the relay lenses 9 and 1
1. After passing through the variable blind 10 and the main condenser lens 12 to reach the mirror 13, where it is reflected almost vertically downward, the pattern area PA of the reticle R is illuminated with substantially uniform illuminance. Since the surface of the variable blind 10 is in a conjugate relationship with the reticle R, a plurality of movable blades constituting the variable blind 10 are opened and closed by a motor (not shown) to change the size and shape of the opening, thereby changing the shape of the reticle R. The illumination visual field can be set arbitrarily. The reticle R is held by a reticle holder 14, and the holder 14 is mounted on a reticle stage RS that can move two-dimensionally in a horizontal plane by a plurality of extendable and contractible (only two are shown in FIG. 1) drive elements 29. . Therefore, by controlling the amount of expansion and contraction of the drive element 29 by the drive element control unit 53, the reticle R can be translated in the optical axis direction and tilted in an arbitrary direction with respect to a plane perpendicular to the optical axis. It has become. Details will be described later,
With the above configuration, it is possible to correct the imaging characteristics of the projection optical system, particularly, the pincushion type and barrel type distortion. still,
Reticle R is positioned such that the center point of pattern area PA coincides with optical axis AX.

The illumination light IL that has passed through the pattern area PA is incident on a projection optical system PL that is telecentric on both sides, and the projection optical system PL forms a projected image of the circuit pattern of the reticle R, and a resist layer is formed on the surface. Projection (imaging) is performed so as to be superimposed on one shot area on the wafer W held so that its surface substantially coincides with the best imaging plane. still,
In this embodiment, it is possible to independently drive each of a part of the lens elements (20, 21, 22, and 23 in the figure) constituting the projection optical system PL.
The imaging characteristics of L, such as projection magnification, spherical aberration, distortion, field curvature, astigmatism, etc., can be adjusted (details will be described later).

A variable aperture stop 32 is provided in the pupil plane Ep of the projection optical system PL or in the vicinity thereof, so that the numerical aperture NA of the projection optical system PL can be changed. . The wafer W is vacuum-sucked on a wafer holder (θ table) 16 and is held on the wafer stage WS via the holder 16. The wafer stage WS can be tilted in any direction with respect to the best image forming plane of the projection optical system PL by the motor 17, and can be finely moved in the optical axis direction (Z direction). Also, this stage WS
Is configured to be two-dimensionally movable by a step-and-repeat method. When transfer exposure of the reticle R to one shot area on the wafer W is completed, stepping is performed to the next shot position. Incidentally, the wafer stage WS
Is described in, for example, JP-A-62-274201.
No. 6,086,045. A movable mirror 19 for reflecting a laser beam from the interferometer 18 is provided at an end of the wafer stage WS.
Is fixed, and the two-dimensional position of the wafer stage WS is always detected by the interferometer 18 with a resolution of, for example, about 0.01 μm.

Further, in FIG. 1, an image forming light beam for forming an image of a pinhole or a slit is supplied to the best image forming plane of the projection optical system PL from an oblique direction with respect to the optical axis AX. Irradiation optical system 30 and wafer W of the image forming light beam
An oblique incidence type focus detection system including a light receiving optical system 31 that receives a light beam reflected by the surface through a beam is provided. The configuration and the like of this focus detection system are disclosed in, for example, Japanese Patent Application Laid-Open No. S60-168112. This is for detecting the in-focus state with the PL.

FIG. 1 shows a main controller 50 for controlling the entire apparatus, and a bar code BC representing the name formed beside the reticle pattern while the reticle R is being conveyed immediately above the projection optical system PL. , A keyboard 51 for inputting commands and data from an operator, and a drive system (motor) for driving the optical integrator block 6 to which a plurality of fly-eye lens groups including the fly-eye lens 7 are fixed. , Gatlen, etc.) 54 are provided. In the main controller 50, names of a plurality of reticles to be handled by the projection exposure apparatus (for example, a stepper) and operation parameters of the stepper corresponding to each name are registered in advance. Then, when the barcode reader 52 reads the reticle barcode BC, the main control device 50 determines, as one of the operation parameters corresponding to the name, the lighting conditions (such as the type of the reticle and the periodicity of the reticle pattern, etc.) that are registered in advance. Is selected from the optical integrator block 6, and a predetermined drive command is output to the drive system 54. Further, as operation parameters corresponding to the above-mentioned names, optimal setting conditions of the variable aperture stops 8, 32 and the variable blind 10 under the fly-eye lens group previously selected, and the projection optical system PL
The calculation parameters (optimum imaging characteristics under each illumination condition, constants representing the rate of change of the amount of change of each image formation characteristic with respect to the drive amount of the lens element) used to correct the image formation characteristics of the above by the correction mechanism described later are also described. These conditions are registered, and these conditions are set simultaneously with the setting of the fly-eye lens group.
As a result, an optimal illumination condition is set for the reticle R mounted on the reticle stage RS. The above operation can also be executed by the operator directly inputting commands and data to main controller 50 from keyboard 51.

Next, a mechanism for correcting the imaging characteristics of the projection optical system PL will be described. As shown in FIG. 1, in this embodiment, the driving element controller 53 drives the reticle R and each of the lens elements 20, 21, 22, and 23 independently to correct the imaging characteristics of the projection optical system PL. It has become possible. As the imaging characteristics of the projection optical system PL, there are a focus position, a projection magnification, spherical aberration, distortion, field curvature, astigmatism, and the like. These values can be individually adjusted, but this embodiment In the example, in order to simplify the description, a case will be described in which the focus position, the projection magnification, the distortion, the spherical aberration, and the curvature of field in the double-sided telecentric projection optical system are particularly adjusted.
In this embodiment, the barrel or pincushion distortion is corrected by the movement of the reticle R.

Now, the lens element 20 is mounted on the support member 2.
4 and is fixed to the lens element 21 (21a, 21a).
b) is fixed to the support member 26. The lens element 22 is fixed to the support member 55, and the lens element 23 is fixed to the support member 56. Lens elements other than the lens elements 20, 21, 22, and 23 are fixed to the lens barrel 28 of the projection optical system PL. In this embodiment, the optical axis AX of the projection optical system PL is fixed to the lens barrel 28. It indicates the optical axis of the lens element.

A plurality of support members 24 (for example, 3
(Two illustrations are shown in the drawing.) The driving member 25 is connected to the support member 26, and the support member 26 is connected to the lens barrel 28 by a plurality of expandable and contractible driving elements 27.
Further, the supporting member 55 is connected to the supporting member 56 by an extendable driving element 57, and the supporting member 56 is connected to the driving element 5.
The lens 8 is connected to the lens barrel 28. Drive element 2
As 5, 27, 29, 57, and 58, for example, an electrostrictive element or a magnetostrictive element is used, and a displacement amount of the drive element according to a voltage or a magnetic field applied to the drive element is obtained in advance. Although not shown here, in consideration of the hysteresis of the drive element, a position detector such as a capacitive displacement sensor or a differential transformer is provided in the drive element, and the position of the drive element corresponding to the voltage or magnetic field applied to the drive element is provided. To enable high-precision driving. With the above configuration, the driving element control unit 5
Reference numeral 3 allows the lens elements 20, 21, 22, and 23 and the peripheral edges 3 to 4 of the reticle R to be independently moved in the optical axis direction by an amount corresponding to a drive command given from the main controller 50. As a result, the lens elements 20, 21, 2
Each of the reticle R and the reticle R can be moved in parallel in the optical axis direction, and can be inclined in an arbitrary direction with respect to a plane perpendicular to the optical axis AX. Further, a drive element that can move in a direction perpendicular to the optical axis may be provided so that each lens element and the reticle can move in a plane perpendicular to the optical axis.

Here, when each of the lens elements 20 and 21 is moved in the optical axis direction, each of the projection magnification M, the curvature of field C, and the focal position F changes at a change rate corresponding to the amount of movement. Further, when each of the lens elements 22 and 23 is moved in the optical axis direction, the spherical aberration S changes. The driving amount of the lens element 20 is x ₁ , the lens element 2 is
The drive amount of 1 is x ₂ , and the drive amount of the lens element 22 is x
_3, when the drive amount of the lens element 22 and x _4, the projection magnification M, curvature C, the change amount of the focal position F and the spherical aberration S .DELTA.M, [Delta] C, [Delta] F, each ΔS is represented by the following formula .

ΔM = C _M1 × x ₁ + C _M2 × x ₂ (1) ΔC = C _C1 × x ₁ + C _C2 × x ₂ (2) ΔF = C _F1 × x ₁ + C _F2 × x ₂ (3) ΔS = C _S1 × x ₃ + C _S2 × x ₄ (4) C _M1 , C _M2 , C _C1 , C _C2 , C _F1 , C _F2 , C _S1 , C _S2
Is a constant representing the rate of change of each change amount with respect to the drive amount of the lens element.

Incidentally, as described above, the focus detection system 30,
Numeral 31 is for detecting the amount of deviation of the wafer surface from the optimum focus position using the optimum focus position of the projection optical system as a zero point reference. Thus, it is given an electrical or an optically appropriate offset x ₅ with respect to the focal detection system 30 and 31,
By positioning the wafer surface using the focus detection systems 30, 31, the lens elements 20, 21,
It is possible to correct the focal position shift due to the driving of the lens 22 and 23. At this time, Equation 3 is represented by the following equation.

ΔF = C _F1 × x ₁ + C _F2 × x ₂ + x ₅ (5) Similarly, when the reticle R is moved in parallel in the optical axis direction, the distortion D and the focus position are changed at a rate of change corresponding to the amount of movement. Each of F changes. The driving amount of reticle R is x
Assuming that ₆ , the distortion D and the change amounts ΔD and ΔF of the focal position F are expressed by the following equations.

ΔD = C _D6 × x ₆ (6) ΔF = C _F1 × x ₁ + C _F2 × x ₂ + x ₅ + C _F6 × x ₆ (7) Here, C _D6 and C _F6 are the reticle R of each change amount. It is a constant representing the rate of change with respect to the drive amount. From the above, Equation 1,
By setting the drive amounts x _{1 to} x ₆ in _2, 4, _6, and 7, the amounts of change ΔM, ΔC, ΔD, ΔF, and ΔS can be arbitrarily adjusted. Here, a case has been described in which five types of imaging characteristics are simultaneously adjusted (set to predetermined imaging characteristics) and corrected. Here, as for the correction, if the change amount of the imaging characteristic due to the change of the illumination condition among the imaging characteristics of the projection optical system is negligible, it is not necessary to correct the imaging characteristic. If the imaging characteristics other than the five types described in the embodiment change significantly, it is necessary to correct the imaging characteristics. Further, in the present embodiment, an example in which correction is performed by moving the reticle R and the lens element as the imaging characteristic adjusting mechanism has been described. However, any other suitable adjusting mechanism may be used in the present embodiment. A method may be adopted in which the space between the lens elements is sealed and the pressure in the sealed space is adjusted.

Here, in this embodiment, the driving element control unit 53
The reticle R and the lens elements 20, 2
Although the lens elements 1, 22, and 23 are movable, the lens elements 20, 21 are particularly easy to control because their effects on projection magnification, distortion, curvature of field, astigmatism, and the like are larger than those of other lens elements. The effect on the spherical aberration of the lens elements 22 and 23 is larger than that of the other lens elements, so that the lens elements 22 and 23 can be easily controlled.

In this embodiment, two lens elements (lens elements 20 and 21) for controlling the projection magnification, distortion and the like are used. However, three or more lens elements may be used. By using three or more groups, the range of movement of the lens element can be increased while suppressing variations in other aberrations, and various types of distortion (trapezoidal, rhombic, etc.), field curvature, and astigmatism are supported. It becomes possible. Further, the lens element for controlling the spherical aberration is not limited to the two-group configuration (the lens elements 22 and 23). By employing the adjustment mechanism having the above configuration, it is possible to sufficiently cope with a change in illumination conditions.

In the above description, the apparatus is provided with the first optical integrator system and the second optical integrator system.
May be a block provided with a plurality of types of optical integrator systems as shown in FIG. FIG. 2 shows an example in which a third optical integrator system and a fourth optical integrator system are provided between the first optical integrator system and the second optical integrator system. Third
The optical integrator system includes a fly-eye lens 63 whose central portion is shielded from light, and an input lens 5a (not shown) to realize annular illumination. The fourth optical integrator system includes four fly-eye lenses 64A and 64A.
B, 64C, 64D and input lenses 61a ₁ , 61
The secondary light source is constituted by b ₁ , 61c ₁ , 61d ₁ and a polygonal prism 60A, and realizes a deformed light source in which a secondary light source is divided into four (realizes a plurality of oblique illuminations). The polyhedral prism 60A includes a quadrangular pyramid (pyramid type) concave prism 60Aa and a convex prism 60Ab. The exit surfaces of the fly-eye lenses of the third optical integrator system and the fourth optical integrator system also have an optical Fourier transform relationship with respect to the reticle pattern surface.

The illumination conditions can be switched by moving the optical integrator block 6 provided with these optical integrator systems.
In addition, the switching of the illumination condition is performed by switching the optical integrator system, but is not limited to this.
For example, a light-shielding plate provided with a ring-shaped opening near the exit surface of the fly-eye lens 7 or a light-shielding plate provided with a plurality of openings may be replaceably provided.

In the second and fourth optical integrator systems, the optical system for inputting a light beam to the fly-eye lens is not limited to a polygonal prism, but may be provided with a mirror, a fiber, a diffraction grating or the like. Further, as described above, in the multiple oblique illumination method, the position of the fly-eye lens (the position where the illumination light beam passes) according to the periodicity (pitch) of the reticle pattern.
Therefore, a plurality of optical integrator systems having different positions of the fly-eye lens may be provided in the block 6. Also, in the annular illumination, a plurality of optical integrator systems having different sizes of the fly-eye lens 63 and the size of the light shielding portion may be provided in the block 6.

Next, a mechanism for measuring the imaging characteristics of the projection optical system PL will be described with reference to FIG. As shown in FIG. 6B, on the surface of the reference member 15, a grid pattern 15m including two sets of slit patterns Gx and Gy is formed.
1. Illuminated from below by the illumination light transmitted by the optical fiber 82, lens 83 and mirror 84.
This illumination light is desirably light in the same wavelength range as the exposure illumination light IL, and may be configured to branch and guide a part of the illumination light IL from the light source 1 by a beam splitter, for example. The illumination light transmitted through the reference member 15 reaches the reticle R via the projection optical system PL, is reflected by the back surface (pattern surface), and returns to the reference member 15 via the projection optical system PL again. Further, the reflected light transmitted through the grating pattern 15m again passes through the optical fiber 82 and the like, and then enters the photodetector 85 composed of a photomultiplier or an SPD or the like, where it is photoelectrically converted and converted into a photoelectric signal corresponding to the light intensity. Output. Main controller 50 receives, for example, a detection signal from a focus detection system (light receiving optical system 31) together with the photoelectric signal from photodetector 85. Then, the wafer stage WS
Is moved in the Z direction, and the level change of the photoelectric signal of the photodetector 85 at that time is obtained. The result is shown in FIG. In the figure, a position f where the signal level has a peak is an optimum focus position (best focus position) at an arbitrary point in the image field. For example, the measurement is performed while the reference member 15 is moved in the image field. Are repeatedly performed, the focus position, the curvature of field, the astigmatism, and the like can be obtained as the imaging characteristics of the projection optical system PL. In the above configuration, since the projection magnification and distortion cannot be measured, for example, a mark formed at a plurality of positions on the reticle R is photoelectrically detected via a reference mark provided on the wafer stage. It is desirable to keep.

Although not shown in FIG. 6A,
In the present embodiment, the exit surface of the optical fiber 82 (reference member side)
It is assumed that a plurality of spatial filters can be interchangeably arranged in the vicinity. Thereby, in response to the change of the illumination condition of the illumination optical system, the illumination condition (for example, the numerical aperture (σ
Value), annular illumination, multiple tilt illumination described below, etc.) can also be arbitrarily changed. At this time, it is desirable to provide a slit pattern with a plurality of pitches on the surface of the reference member 15 corresponding to the reticle pattern.

In this embodiment, the angle of a parallel flat glass (not shown) provided beforehand in the light receiving optical system 31 is adjusted so that the image plane becomes the zero point reference, and the focus detection system is used. Is assumed to be performed. Further, for example, a horizontal position detection system as disclosed in Japanese Patent Application Laid-Open No. 58-113706 may be used, or the focus positions at arbitrary plural positions in the image field of the projection optical system PL may be detected. By configuring a focus detection system (for example, forming a plurality of slit images in an image field), the inclination of a predetermined area on the wafer W with respect to the imaging plane can be detected. Next, with reference to FIG. 3 and FIG. 4, an example of the multiple oblique illumination method (deformed light source) and its principle will be described.

FIG. 3 is a diagram showing the state of generation of diffracted light from a circuit pattern and image formation when a reticle is illuminated using the multiple oblique illumination method. On the lower surface of the reticle R (on the side of the projection optical system PL), a one-dimensional line-and-space pattern composed of a transmission part Ra and a light-shielding part Rb is drawn as a circuit pattern. In the projection exposure apparatus (FIG. 1) used in the present embodiment, a local area through which the illumination light beam passes has a center at a position decentered from the optical axis in the pupil plane of the illumination optical system as described later. I have. Therefore, the illumination light beam L0 illuminating the reticle R is
Is incident on the reticle R at a predetermined incident angle ψ from a direction (X direction) substantially perpendicular to the direction in which the circuit pattern is drawn (periodic direction). The incident angle ψ and the incident direction are uniquely determined by the position of the diffracted light generated in the pattern on the reticle in the pupil plane of the projection optical system.

Now, from the pattern on the reticle,
0th order in the direction of the diffraction angle according to the fineness (width, pitch) of the
Diffracted light D_o, + 1st order diffracted light D_p, -1st order diffracted light D_mDeparts
Live. The resolution limit of the pattern by the conventional illumination method is
Whether ± 1st order diffracted light can pass through the projection optical system
Is determined. In FIG. 3, the light transmitted through the projection optical system PL
The light that reaches Eha W is the zero-order diffracted light of the three light beams.
D_oAnd + 1st order diffracted light D _pAnd these two luminous fluxes
Represents an interference fringe, ie, an image of a circuit pattern, on the wafer W.
To achieve. That is, the apparent NA increases. Therefore,
Conventionally, when the pattern pitch is P, P> λ / NA
The pattern size given by the degree is the resolution limit
On the other hand, in the multiple oblique illumination method in this embodiment,
Almost P> λ / 2NA is the resolution limit.

In FIG. 3, the 0th-order diffracted light _Do and +
1-order diffracted light D _p is assumed to pass through the substantially symmetrical optical paths with respect to the optical axis AX. This is because the incident angle の of the illumination light beam Lo is sin
ψ = sin θ / 2 = λ / 2P. At this time, when the wafer W is defocused, 0
Next time produce the diffracted light D _o and +1 approximately the same amount of the wavefront aberration and-order diffracted light D _p (due to defocus). This means that the wavefront aberration with respect to the defocus amount ΔF is ×× ΔF sin ² t (where t is the angle of incidence of each diffracted light on the wafer). This is because the incident angles t are almost equal. By the way, the cause of distorting (blurring) the pattern image on the wafer is a difference in wavefront aberration between light beams. However, the apparatus used in the present embodiment (e.g., FIG. 5), for 0 wavefront aberration of the diffracted light D _o and + 1st-order diffracted light D _p to be irradiated onto the wafer is substantially equal, met equivalent defocus amount ΔF However, the degree of blur is smaller than that of a conventional exposure apparatus. That is, the depth of focus is deep.

In FIG. 3, the 0th-order diffracted light _Do and +
Although the first-order diffracted light D _p is assumed to be substantially symmetric with respect to the optical axis AX, in order to increase the depth of focus, the pupil plane Ep is required.
The two diffracted lights need not be symmetrical with respect to the optical axis AX, but only need to pass through a position that is approximately equidistant from the optical axis AX. Here, since the fineness (line width, pitch) and directionality of the pattern of the reticle used in the exposure apparatus are not specified to one type, the pupil of the illumination optical system of the projection exposure apparatus used in the present embodiment is not specified. The center position of the local region through which the illumination light beam passes on the surface, for example, the position in the pupil plane of the illumination optical system of the two fly-eye lens groups 62A and 62B shown in FIG. 1 is variable (exchangeable) according to the type of pattern. ) Is desirable.

The optimum position of the fly-eye lens will be briefly described. FIG. 4A shows a so-called one-dimensional line-and-space pattern in which transmissive portions Ra and light-shielding portions Rb extend in the Y direction and are regularly arranged at a pitch P in the X direction. At this time, for example, the individual fly-eye lens groups 62A and 62B of FIG. 1 (that is, the position of the secondary light source group)
Are located on the line segment Lα in the Y direction assumed in the pupil plane 70 of the illumination optical system and the line segment Lβ as shown in FIG.
Any position above. FIG. 4 (B) a view of the pupil plane 70 of the illumination optical system corresponding to the reticle pattern RP ₁ from the optical axis AX direction, the coordinate system XY as defined in the pupil plane 70
FIG saw reticle pattern RP ₁ from the same direction 4
Same as (A).

Now, as shown in FIG. 4B, in the pupil plane 70, the distances α and β from the optical axis AX (pupil center) to the line segments Lα and Lβ are α = β. alpha, beta corresponds to the incident angle [psi _X in the X direction of the illumination light with respect to the reticle, when the lambda and the exposure wavelength is the distance that satisfies sinψ _X = λ / 2Px described above. Therefore, the fly-eye lens groups 62A, 62A
If the center of 2B (that is, each center of gravity of the light quantity distribution of the secondary light source group) is on the line segments Lα and Lβ, the fly-eye lens group 62A for the line-and-space pattern as shown in FIG. , 62B, the two diffracted lights of the 0th-order diffracted light and one of the ± 1st-order diffracted lights generated by the illumination light from the pupil plane Ep of the projection optical system PL are substantially equidistant from the optical axis AX. Will pass through a certain position. Therefore, as described above, the depth of focus with respect to the line and space pattern (FIG. 4A) can be maximized, and high resolution can be obtained.

On the other hand, FIG. 4 (C) shows the case reticle pattern is the so-called isolated space pattern, and the pattern RP ₂ in the X direction (lateral direction) pitch Px, Y direction (vertical direction) pitch becomes Py It is assumed that FIG.
FIG. 4D is a diagram showing the optimum position of each fly-eye lens group in this case, and the position and rotational relationship with FIG.
This is the same as the relationship between (A) and (B). Incidentally, it is desirable to be formed of four local regions in the pupil plane 70 of the illumination optical system (illumination light beam) in the case of a two-dimensional pattern RP _2, thus device having the above structure (Fig. 1) In the fourth Optical What is necessary is just to provide four fly-eye lens groups like an integrator system (FIG. 2).

Now, a two-dimensional pattern R as shown in FIG.
When illumination light P ₂ is incident, a two-dimensional direction of the periodicity of the pattern RP ₂ (Pitch X: Px, Pitch Y: Py) diffracted light in a two-dimensional direction is generated in accordance with the. 2 as shown in FIG.
Also in the _two- dimensional pattern RP2, one of the 0th-order diffracted light and ± 1st-order diffracted light in the diffracted light is projected by the projection optical system P.
The depth of focus can be maximized by passing through a position that is substantially equidistant from the optical axis AX on the pupil plane Ep of L.

The line segments as shown in FIG. 4 (D) L [alpha, if each center of the two fly-eye lens unit on the L? (2 primary light source group), the depth of focus for the two-dimensional X-direction component of the pattern RP ₂ Can be max. Similarly, when the incident angle of the Y-direction of the illumination light to the reticle and the [psi _Y, gamma, epsilon
As the distance that satisfies sinψ _Y = λ / 2Py, the line segment L
Two fly-eye lens groups (secondary light source groups) on γ and Lε
If each center, the depth of focus can be maximized for two-dimensional pattern RP ₂ in the Y direction component.

As described above, the illumination light beam from the fly-eye lens group (secondary light source group) arranged at each position in the pupil plane 70 shown in FIG. 4B or 4D becomes the reticle pattern RP ₁ or RP ₂ . When entering, the one and the zero-order diffraction light component D _o of + 1st-order diffracted light component D _p or -1 order diffraction component D _m from the reticle pattern is from the optical axis AX on the pupil plane Ep of the projection optical system PL It passes through a position that is almost equidistant. Therefore, as described above, a projection type exposure apparatus having a high resolution and a large depth of focus can be realized.

In this case, the reticle pattern shown in FIG.
Although only the two examples shown in (A) or (C) were considered, attention was paid to the periodicity (fineness) of other patterns, and the + 1st-order diffracted light component or -1 from the pattern was considered.
The pupil plane 70 of the illumination optical system is such that two light beams, one of the zero-order diffracted light components and the zero-order diffracted light component, pass through the pupil plane Ep of the projection optical system PL at a position substantially equidistant from the optical axis AX. Fly-eye lens group (secondary light source group)
What is necessary is just to set the center position of. The positional relationship between the other order of the diffracted light, for example, any one of the ± 2nd-order diffracted light and the 0th-order diffracted light, may be substantially equidistant from the light source AX on the pupil plane of the projection optical system.

When the reticle pattern includes a two-dimensional periodic pattern as shown in FIG.
Focusing on the second-order diffracted light component, the pupil plane E of the projection optical system PL
On p, higher-order diffracted light components of the first or higher order distributed in the X direction (first direction) around the one 0-order diffracted light component;
There may be first-order or higher-order diffracted light components distributed in the Y direction (second direction). Therefore, assuming that a two-dimensional pattern is favorably imaged with respect to one specific 0th-order diffracted light component, one of the higher-order diffracted light components distributed in the first direction is represented by:
One of the higher-order diffracted light components distributed in the second direction and a specific 0
The specific zero-order diffracted light component (1) is distributed such that the three diffracted light components are distributed at substantially the same distance from the optical axis AX on the pupil plane Ep.
The position of the fly-eye lens group as the two secondary light source groups may be adjusted. For example, in FIG. 4D, the respective center positions of the fly-eye lens group (secondary light source group) are indicated by points Pζ, Pη, P
It is good to match with either κ or Pμ. Point Pζ, P
Each of η, Pκ, and Pμ is a line segment Lα or Lβ (an optimal position for the periodicity in the X direction, ie, 0th-order diffracted light and X
At positions where one of the ± 1st-order diffracted lights in the direction is substantially equidistant from the optical axis on the pupil plane Ep of the projection optical system), and at the intersection of the line segment Lγ or Lε (optimal position for periodicity in the Y direction). Therefore, the light source position is optimal in either the X direction or the Y direction.

In the above description, a two-dimensional pattern having a two-dimensional direction at the same position on the reticle has been assumed, but a plurality of patterns having different directions exist at different positions in the same reticle pattern. To the above method. When the pattern on the reticle has a plurality of directions or finenesses, the optimum position of each fly-eye lens group corresponds to each directionality and fineness of the pattern as described above. Alternatively, each fly-eye lens group may be arranged at an average position of each optimum position. In addition, the average position may be a load average taking into account the weight according to the fineness and importance of the pattern.

Further, the light beams emitted from the fly-eye lens groups are incident on the reticle at an angle. At this time, if the direction of the center of gravity of the light quantity of these inclined incident light beams (plurality) is not perpendicular to the reticle, the problem that the position of the transferred image shifts in the in-plane direction of the wafer W when the wafer W is slightly defocused occurs. I do. In order to prevent this, the direction of the center of gravity of the light quantity of the illumination light beam (plural) from each fly-eye lens group is set to be perpendicular to the reticle pattern, that is, parallel to the optical axis AX. That is, when an optical axis (center line) is assumed for each fly-eye lens group, a position vector of the optical axis (center line) in the Fourier transform plane with respect to the optical axis AX of the projection optical system PL, and What is necessary is just to make the vector sum of the product of the light amount emitted from the fly-eye lens group and the light amount substantially zero. Another simpler method is
The number of the secondary light sources is 2m (m is a natural number), and the positions of the m light sources are determined by the above-described optimization method (FIG. 4), and the remaining m light sources are positions substantially symmetric with respect to the optical axis AX. It should just be placed in.

Next, the operation of the projection exposure apparatus according to this embodiment will be described. Here, an example of the switching operation between the first optical integrator system and the second optical integrator system will be described. First, the case where the first optical integrator system is arranged will be described. Suitable reticle R ₁ is set on the reticle stage RS to normal illumination. In this case, the first optical integrator system (5, 7) are arranged from the information of the bar code BC provided on the reticle R ₁ in the optical path of the illumination optical system. Here, the focus calibration is performed by the above-described apparatus of FIG. 6, and when the wafer W is placed at the image forming position, the output of the focus sensors 30 and 31 is adjusted to be zero.

As described above, in normal lighting,
Having a predetermined amount of spherical aberration improves the depth of focus. Therefore, here, the bar code has information about the amount of spherical aberration adjustment is recorded in the BC, the main controller 50 driving amount (reference lens and a constant C _S and the spherical aberration related to the spherical aberration of the above From the position). Then, the spherical aberration on the wafer W side becomes
For example, the lens 2 has a spherical aberration curve shown in FIG.
Move 1,22. FIG. 5 is a diagram showing the spherical aberration characteristics, in which the direction of the Z axis is an optical code, and the direction away from the lens is plus (+). ΔSA indicates the amount of spherical aberration at a predetermined NA. For a lens having an NA of about 0.6, ΔSA is preferably about 2 to 5 μm. Thus, when spherical aberration is generated, the best focus position is Z = 0.
The position in the Z direction is slightly shifted to the plus (+) side from (the position without spherical aberration). This defocus amount ΔZ is added to the focus sensors 30 and 31 as an offset. The wafer stage WS makes the surface of the wafer W coincide with a position shifted in the optical axis direction by the offset amount ΔZ. The defocus amount may be corrected by driving the lens. The driving amount of the lens may be recorded directly on the barcode BC.

Next, the case of switching to the second optical integrator system will be described. The reticle R ₂ using multiple oblique illumination is set on the reticle stage RS, based on the information from the bar code BC of the reticle R _2, the main control system 50 controls the drive system 54. Drive system 54
Switches the optical integrator block, and arranges the second optical integrator system (60, 61, 62) in the optical path of the illumination optical system. The main control system 50
Sets the σ value of the illumination optical system to an appropriate value. Here, the σ value is set to be 0.1 to 0.3.

The second optical integrator system (6
0, 61, and 62), the lenses 21 and 22 are returned to the reference position because there is no spherical aberration and the depth of focus is large. At this time, the offset amount of the focus sensors 30 and 31 becomes zero. Here, this is an example in which the focus calibration of the focus sensors 30 and 31 is performed without spherical aberration. If the calibration is performed when spherical aberration is given, the offset amount is zero with spherical aberration. Has a predetermined offset amount without spherical aberration.

Similarly, the spherical aberration can be adjusted according to the switching between the first fly-eye lens system and the third and fourth fly-eye lens systems. Incidentally, even when the phase shift reticle is used in the first fly-eye lens system, the lens systems 22 and 23 are moved so as to make the spherical aberration zero by the same operation. Switching of illumination conditions (switching between the first optical integrator system and the second, third, and fourth optical integrator systems, or switching between the second, third, and fourth optical integrator systems)
Switching between optical integrator systems, switching between a normal reticle and a phase shift reticle, and switching between optical integrator systems with different fly-eye lens positions) changes the position through which the light beam passes in the projection optical system. , Distortion fluctuates. In each of the switching of the illumination conditions, the amount of change in the imaging characteristics is registered in the barcode BC, and the main controller 50 calculates the amount of lens drive in the same manner as the above-described operation. Based on this, the reticle R (or the lens element 20, 2,
What is necessary is just to move 1). If the focus position changes accordingly, the offset is added to the focus sensors 30 and 31 as described above, and the wafer stage WS is moved to add a predetermined amount of offset from the focus reference position. Is placed on the wafer W. Alternatively, the focus offset may be adjusted by moving the lens as described above.

In the above description, the operation focusing on distortion has been described. However, with respect to changes in other optical characteristics, for example, curvature of field, fluctuation in magnification, and the like, the lens 20 is switched in accordance with the switching of the illumination conditions as described above. , 21, 22 and the position of the reticle. Each time the lighting conditions are switched,
Correction may be performed by performing focus calibration or measuring distortion or the like.

In the above embodiment, the reticle R or the lens elements 20, 21, 22, 2 of the projection optical system are used.
3, the aberration state can be changed by moving the entire projection optical system. Therefore, the present invention can be realized even if the entire projection optical system is moved up and down by the driving member. Further, the movement of the reticle R and the entire projection optical system and the movement of some lenses may be performed together.

Although the projection type exposure apparatus has been described above, it may be a reflection type or a catadioptric type. Further, when the projection optical system is a catadioptric type including a reflecting mirror, the same effect can be obtained by moving the reflecting mirror instead of the lens.

[0057]

As described above, according to the present invention, the illumination conditions can be varied according to the reticle pattern, and the best imaging characteristics can be obtained under each illumination condition. In particular, by adjusting the spherical aberration in accordance with switching between the normal illumination, the annular zone, and the deformed light source, it is possible to obtain an optimum depth of focus under each illumination condition.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a projection exposure apparatus according to one embodiment of the present invention;

FIG. 2 is a diagram showing an exchange mechanism for interchangeably arranging a plurality of optical integrator systems according to one embodiment of the present invention;

FIG. 3 is a diagram for explaining the principle of a multiple oblique illumination method employed in one embodiment of the present invention;

FIG. 4 is a view for explaining the arrangement of fly-eye lens groups in the multiple oblique illumination method employed in one embodiment of the present invention;

FIG. 5 is a diagram showing spherical aberration characteristics in normal illumination employed in an embodiment of the present invention;

FIG. 6 is a diagram illustrating an operation of measuring an imaging characteristic of a projection optical system using a reference member.

[Explanation of symbols]

 6 Optical integrator block 7, 62, 63, 70 Fly eye lens 8, 32 Variable aperture stop 20, 21, 22, 23 Lens element 25, 27, 29, 57, 58 Drive element 30, 31 Focus Sensor 50: Main controller 53: Controller 54: Drive system R: Reticle W: Wafer WS: Wafer stage

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/027

Claims (22)

(57) [Claims] 1. A an illuminating optical system for irradiating the illumination light from the light source to a mask, a projection exposure apparatus having a projection optical system for projecting the illumination light onto a photosensitive substrate, the mask within the illumination optical system Actual pattern surface
The illumination on a predetermined surface qualitatively related to a Fourier transform
The light intensity distribution of light should be variable and should be transferred onto the photosensitive substrate
When at least a part of the pattern has periodicity,
Light of the illumination optical system at an incident angle corresponding to the fineness of the pattern
The illumination light is inclined with respect to the axis and enters the mask.
As described above, at least a part of the pattern is formed on the predetermined surface.
The optical axis of the illumination optical system with respect to the direction periodically arranged
Has a center at a position eccentric from, and according to the fineness
Regions where the distance from the optical axis is determined to be substantially equal
A projection exposure apparatus comprising: a change unit for increasing the light amount distribution within the unit; and an adjustment unit for adjusting the imaging characteristics of the projection optical system according to the change in the light amount distribution . 2. The method according to claim 1, wherein the changing unit is configured to control the light in the plurality of areas.
When increasing the amount distribution, the illumination light is converted to light of the illumination optical system.
An optical member for distributing off-axis the light source and the illumination optical system;
Between the optical integrator in the
The projection exposure apparatus according to claim 1, wherein: 3. An optical system according to claim 1, wherein said changing means changes the light amount distribution.
After the change, the optical member disposed between the
2. The projection exposure apparatus according to claim 1 , wherein the optical system is replaced with another optical member selected according to the light amount distribution of the projection light. 4. The optical member is a prism or a diffraction element.
4. The projection exposure apparatus according to claim 3, wherein: Wherein said adjusting means according to claim 1, characterized in that for driving the optical element or the mask of the projection optical system
The projection exposure apparatus according to any one of claims 1 to 4 . 6. The method according to claim 1, wherein the plurality of regions are on the predetermined surface.
First type in which at least a part of the pattern is periodically arranged
Direction substantially parallel to a second direction orthogonal to the first direction, and the first direction
With respect to the pattern of the pattern from the optical axis of the illumination optical system
A pair of first lines separated by a distance corresponding to the fineness in the first direction
6. A method according to claim 1, wherein the first and second parts are arranged on a minute.
The projection exposure apparatus according to claim 1. 7. The method according to claim 1, wherein at least a part of the pattern is the second pattern.
When also periodically arranged in the direction, the plurality of regions,
On the predetermined surface, substantially parallel to the first direction, and
The pattern from the optical axis of the illumination optical system in two directions
Of a pair separated by a distance corresponding to the fineness in the second direction.
A second segment, and a pair of first segments arranged on each segment;
The projection exposure apparatus according to claim 6, wherein the projection exposure apparatus is used. 8. The plurality of regions are connected to the pair of first line segments.
It is arranged on the intersection with the pair of second line segments.
The projection exposure apparatus according to claim 7, wherein 9. A position where two diffracted lights having different orders generated from the pattern by the irradiation of the light beams emitted from the respective regions are located on the pupil plane of the projection optical system and have substantially equal distances from their optical axes. The projection exposure apparatus according to any one of claims 1 to 8 , wherein the position of each of the regions is determined so as to pass through. 10. The incident angle ψ is sinψ = λ / 2P, where λ is the wavelength of the illumination light and P is the pitch of the pattern.
The projection exposure apparatus according to any one of claims 1 to 9 , wherein the position of each of the regions is determined so as to satisfy the following relationship . Wherein said pattern it to the first and second directions
Are respectively periodically arranged Rutoki, said emitted from each region
0-order diffracted light generated from said pattern by the irradiation of Ruhikaritaba, the 0 one of higher-order diffracted light distributed to the first direction about the order diffracted light, and distributed in the second direction about the zero-order diffracted light one of the high-order diffracted light, so as to be distributed substantially equidistant from the optical axis on the pupil plane of the projection optical system, any one of claims 1 to 10, characterized in that to determine the position of each region one Item 6. The projection exposure apparatus according to Item 1. 12. The method according to claim 11, wherein the plurality of regions are on the predetermined surface.
That they are arranged almost symmetrically with respect to the optical axis of the illumination optical system.
A projection according to any one of the preceding claims, characterized in that it is a projection.
Exposure equipment. 13. An element manufacturing method using the projection exposure apparatus according to any one of claims 1 to 12 . 14. A projection exposure method for irradiating a mask with illumination light from a light source through an illumination optical system and exposing a photosensitive substrate with the illumination light via a projection optical system, wherein the pattern to be transferred onto the photosensitive substrate is provided. Substantially within the illumination optical system with respect to the pattern surface of the mask.
While changing the light amount distribution of the illuminating light on a predetermined surface that is in the relationship of Fourier transform, adjusting the imaging characteristics of the projection optical system according to the change in the light amount distribution ,
When at least a portion has periodicity, the pattern
With respect to the optical axis of the illumination optical system at an incident angle according to the degree of fineness
The illumination light is inclined so as to enter the mask,
At least a part of the pattern is periodically arranged on a predetermined surface.
Decentered from the optical axis of the illumination optical system with respect to the row direction
The optical axis according to the fineness.
The light within a plurality of regions where the distance between
A projection exposure method characterized by increasing the amount distribution . 15. The light intensity distribution is enhanced in the plurality of regions.
When distributing the illumination light outside the optical axis of the illumination optical system,
Optical member in the illumination optical system and the light source
Claim to be arranged between the integrator
Item 15. The projection exposure method according to Item 14. 16. The light source according to claim 16, wherein said light amount distribution is changed.
Source and an optical integrator in the illumination optical system
The optical member disposed between the light sources is adapted to the changed light amount distribution.
Flip to said be replaced with other optical members to be selected by
15. The projection exposure method according to claim 14, wherein 17. The device according to claim 17, wherein the plurality of regions are located on the predetermined surface in front of the predetermined surface.
A first pattern in which at least a part of the pattern is periodically arranged
A direction substantially parallel to a second direction orthogonal to the direction, and the first direction
Direction from the optical axis of the illumination optical system to the front of the pattern
The first pair of first members separated by a distance corresponding to the fineness in the first direction.
17. The image display device according to claim 14, which is arranged on a line segment.
The projection exposure method according to any one of the above. 18. The method according to claim 18, wherein at least a part of said pattern is
When periodically arranged in two directions, the plurality of areas
Is substantially parallel to the first direction on the predetermined surface, and
The pattern from the optical axis of the illumination optical system in the second direction.
At a distance corresponding to the fineness of the screen in the second direction.
Arranged on each of the pair of second line segments and the pair of first line segments.
18. The projection exposure according to claim 17, wherein the projection exposure is performed.
Method. 19. The plurality of regions include the pair of first line segments.
And a pair of the second line segments.
19. The projection exposure method according to claim 18, wherein: 20. Irradiation of a light beam emitted from each of the regions
Therefore, two different orders generated from the pattern are used.
Two diffracted light beams from its optical axis on the pupil plane of the projection optical system
Position of each of the above regions so that
20. The method according to claim 14, wherein the position is determined.
13. The projection exposure method according to claim 1. 21. The wavelength of the illumination light is λ,
When the pitch is P, the incident angle ψ is sinψ = λ / 2P
Determine the position of each area so as to satisfy the relationship
The method according to any one of claims 14 to 20, wherein
Projection exposure method. 22. The method according to claim 19, wherein the pattern is displaced in first and second directions.
When they are periodically arranged, they are emitted from each of the regions.
0 next time generated from the pattern by irradiation of
Folded light, distributed in the first direction around the zero-order diffracted light
One of the higher-order diffracted lights and the zero-order diffracted light as a center.
One of the higher-order diffracted lights distributed in the second direction
Distributed almost equidistant from the optical axis on the pupil plane of the shadow optical system
And determining a position of each of the regions.
Item 22. The projection exposure method according to any one of items 14 to 21.