JP3084760B2 - Exposure method and exposure apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method used for transferring a circuit pattern of a semiconductor integrated device or the like or a pattern of a liquid crystal device, and a projection type exposure apparatus.

[0002]

2. Description of the Related Art Forming a circuit pattern of a semiconductor or the like requires a step generally called a photolithographic technique.
In this step, a method of transferring a reticle (mask) pattern onto a sample substrate such as a semiconductor wafer is usually adopted.
A photosensitive photoresist is applied on the sample substrate, and a circuit pattern is transferred to the photoresist according to an irradiation light image, that is, a pattern shape of a transparent portion of the reticle pattern. In a projection type exposure apparatus, a circuit pattern to be transferred drawn on a reticle is projected and imaged on a sample substrate (wafer) via a projection optical system.

In a conventional projection exposure apparatus, the distribution of the amount of illumination light flux incident on an optical integrator incidence surface such as the fly-eye lens described above is substantially circular (or rectangular) around the optical axis of the illumination optical system. Was almost uniform. FIG. 11 shows the above-described conventional projection optical system. The illumination light beam L130 of the reticle 7 irradiates the reticle pattern 13 via the fly-eye lens 6, the spatial filter 12, and the condenser lens 11 in the illumination optical system. Here, the spatial filter 12 is disposed on the reticle-side focal plane 6b of the fly-eye lens 6, that is, a Fourier transform plane (hereinafter abbreviated as a pupil plane) with respect to the reticle 7, or in the vicinity thereof, and is centered on the optical axis AX of the projection optical system. And a secondary light source (surface light source) image formed in the pupil plane is limited to a circular shape. Thus, the illumination light that has passed through the pattern 13 of the reticle 7 forms an image on the resist layer of the wafer 16 via the projection optical system 15. Here, a solid line representing a light beam represents a principal ray of light emitted from one point.

At this time, the ratio between the numerical aperture of the illumination optical system (6, 12, 11) and the numerical aperture on the reticle side of the projection optical system 15, a so-called σ value, is an aperture stop (for example, the aperture diameter of the spatial filter 12).
The value is generally about 0.3 to 0.6. Illumination light L130 is diffracted by the pattern 13 which is patterned on the reticle 7, zero-order diffracted light D ₀ from the pattern 13, + 1st-order diffracted light D _P, -1-order diffracted light D _m
Occurs. Each diffracted light (D ₀ , D _m , D _P )
Is condensed by the projection optical system 15 and the wafer (sample substrate) 1
An interference fringe is generated on 6. This interference fringe is a pattern 13
It is an image of. At this time, the 0th-order diffracted light D ₀ and the ± 1st-order diffracted light D
_P, the angle theta (reticle side) of D _m is sinθ = λ / P
(Λ: exposure wavelength, P: pattern pitch).
As the pattern pitch becomes finer, sin θ increases, and sin θ becomes the reticle-side numerical aperture (N
If it exceeds A _R ), the ± first-order diffracted lights D _P and D _m cannot pass through the projection optical system.

At this time, the zero-order diffracted light D ₀ is placed on the wafer 16.
Only the light beam arrives and no interference fringes occur. That is, sin θ>
Not obtained image of the pattern 17 in the case where the NA _R, it becomes impossible to transfer the pattern 13 on the wafer 16. From the above, in the conventional exposure apparatus, the pitch P at which sin θ = λ / P ≒ NA _R is given by the following equation. P ≒ λ / NA _R (1) Therefore, to transfer a finer pattern, select whether to use an exposure light source with a shorter wavelength or a projection optical system with a larger numerical aperture. I needed to. Of course, efforts can be made to optimize both the wavelength and the numerical aperture. Also, thin out the pattern at predetermined intervals,
The pattern is decomposed into multiple parts so as to lower the pattern fineness (spatial frequency), and multiple exposures are performed using a reticle on which each of the separated patterns is formed. A method of forming on a wafer has also been considered. Japanese Patent Publication No. Sho 62-50811 discloses a so-called phase shift reticle that shifts the phase of light transmitted from a specific portion of the circuit portion of the reticle by π from the phase of light transmitted from another portion. And so on. Use of this phase shift reticle enables transfer of a finer pattern than in the past.

[0006]

However, in the conventional exposure apparatus, shortening the wavelength of the illumination light source (for example, 200 nm or less) is difficult because there is no suitable optical material usable as a transmission optical member. It is difficult at the moment for reasons. At present, the numerical aperture of the projection optical system is already close to the theoretical limit, and it is almost impossible to increase the numerical aperture further. Further, even if the aperture can be made larger than the current state, the depth of focus represented by ± λ / 2NA ² decreases sharply with an increase in the numerical aperture, and the depth of focus required for actual use is further reduced. The problem of becoming more pronounced. Further, simply reducing the fineness by thinning out the pattern does not always provide a sufficient resolution. On the other hand, for the phase shift reticle,
Many problems remain, such as high costs due to the complexity of the manufacturing process, and inspection and repair methods have not yet been established.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to realize an exposure method and a projection type exposure apparatus capable of obtaining a high resolution and a large depth of focus. It is an object of the present invention to realize an exposure method and a projection exposure apparatus for exposing a circuit pattern having a high resolution and a large depth of focus over the entire pattern.

[0008]

According to the present invention, in order to solve such a problem, in a pattern to be formed having a high degree of fineness in a plurality of directions, a portion having a difference in fineness or a difference in a periodic direction. By decomposing a part into at least two parts and performing exposure at least twice, an illumination optical system, or a position near the Fourier transform equivalent surface of the reticle (mask), or each surface is provided. Exposure is performed by providing illumination light passing through a region defined at a position decentered by an amount corresponding to the fineness of the decomposition pattern or the periodic direction from the optical axis of the projection optical system, and the respective decomposition patterns are superimposed on the wafer. Thus, a desired pattern is obtained.

[0009]

The circuit pattern 13 drawn on the reticle (mask) generally contains many periodic patterns.
Accordingly, the 0th-order diffracted light component D is obtained from the reticle pattern 13 irradiated with the illumination light from one fly-eye lens group 6A.
_{The 0th} and ± 1st-order diffracted light components D _P , D _m and higher-order diffracted light components are generated in directions corresponding to the periodicity of the pattern.
At this time, since the illumination light beam (center line) is incident on the reticle 7 at an inclined angle, the generated diffracted light components of each order also have an inclination (angle shift) of the reticle pattern 13 as compared with the case where the illumination is performed vertically. Arising from Illumination light L120 in FIG. 10 is incident on reticle 7 at an angle of ψ with respect to the optical axis.

The illumination light L120 is applied to the reticle pattern 13.
Is further diffracted and proceeds in a direction inclined by ψ with respect to the optical axis AX.
0th order diffracted light D₀, Θ for the 0th order diffracted light_PJust leaned
+ 1st order diffracted light D_P, And zero-order diffracted light D₀For θ_mIs
-1st order diffracted light D _mOccurs. But
The illumination light L120 is projection optics that is telecentric on both sides.
The reticle package is tilted by an angle に 対 し て with respect to the optical axis AX of the system 15.
0th order diffracted light D₀Also projection optics
Travels in a direction inclined by an angle に 対 し て with respect to the optical axis AX of the system
You.

Accordingly, the + 1st-order light D _P travels in the direction of θ _P + ψ with respect to the optical axis AX, and the −1st-order diffracted light D _m becomes
Proceeds in the direction of θ _m −ψ. At this time, the diffraction angle θ
_P, theta _m respectively _{sin (θ P + ψ) -} sinψ = λ / P ...... (2) is _{sin (θ m -ψ) + sinψ} = λ / P ...... (3).

[0012] Here, + 1-order diffracted light D _P, -1 both-order diffracted light D _m is assumed to transmit the pupil Ep of the projection optical system 15. When the diffraction angle increases with the miniaturization of the reticle pattern 13, the reticle pattern 13 first advances in the direction of the angle θ _P + ψ.
1-order diffracted light D _P can not be transmitted through the pupil Ep of the projection optical system 15. That is, the relationship becomes sin (θ _P + ψ)> NA _R. But since the illumination light L120 is incident inclined with respect to the optical axis AX, -1-order diffracted light D _m at a diffraction angle in this case is possible enter the projection optical system 15. That is, the relationship sin (θ _m −ψ) <NA _R is satisfied.

Therefore, the zero-order diffracted light D ₀ is placed on the wafer 16.
If -1 interference fringes caused by two light beams of the diffracted light D _m occurs. This interference fringe is an image of the reticle pattern 13. When the reticle pattern 13 has a line and space ratio of 1: 1, the image of the reticle pattern 13 is formed on a resist applied on the wafer 16 with a contrast of about 90%. Patterning becomes possible.

The resolution limit at this time is when sin (θ _m -ψ) = NA _R (4), and therefore, NA _R + sinψ = λ / PP = λ / (NA _R + sinψ). .. (5) is the pitch of the smallest transferable pattern on the reticle side.

As an example, if sinψ is determined to be about 0.5 × NA _R , the minimum pitch of the pattern on the reticle that can be transferred is P = λ / (NA _R + 0.5NA _R ) = 2λ / 3NA _R. ... (6)

Here, the zero-order diffracted light component on the pupil plane and -1
The interval between the next-order diffracted light components in the pattern period direction is proportional to the fineness (spatial frequency) of the reticle pattern 13. Equation (4) means that this interval is maximized to obtain the maximum resolution. On the other hand, as shown in FIG. 11, in the case of a conventional exposure apparatus in which the distribution of the illumination light on the pupil Ep is within a circular area centered on the optical axis AX of the projection optical system 15, the resolution limit is (1). ) P ≒ λ / NA _R as shown in the equation. Therefore, it can be seen that a higher resolution than the conventional exposure apparatus can be realized.

Next, a reticle pattern is irradiated with exposure light in a specific incident direction and an incident angle, and an image forming pattern is formed on a wafer using a 0th-order diffracted light component and a 1st-order diffracted light component. The reason why the depth of focus also increases will be described. As shown in FIG.
In the case of coincidence with the focal position of 5 (the best imaging plane),
Each diffracted light that exits one point in the reticle pattern 13 and reaches one point on the wafer 16 has the same optical path length regardless of which part of the projection optical system 15 passes. Therefore, even when the zero-order diffracted light component penetrates substantially the center (near the optical axis) of the pupil plane Ep of the projection optical system 18 as in the related art, the optical path lengths of the zero-order diffracted light component and the other diffracted light components are equal. , The mutual wavefront aberration is also zero. However, when the wafer 16 is in a defocused state in which the focal position of the projection optical system 15 does not precisely coincide with the focal point of the projection optical system 15, the optical path length of the high-order diffracted light obliquely incident is focused on the 0-order diffracted light passing near the optical axis. The distance is short in front (away from the projection optical system 15) and long behind the focal point (approaching to the projection optical system 15), and the difference depends on the difference in the incident angle. Therefore, the 0th-order, 1st-order,... Diffracted lights mutually form wavefront aberrations, causing blur before and after the focal position.

The wavefront aberration caused by the aforementioned defocus, the sine of the incident angle theta _w when the amount of shift from the focus position of the wafer 16 [Delta] F, each diffracted light incident on the wafer 16 r (r =
If you sinθ _w), is the amount given by ΔF · r ^2/2. (At this time, r represents the distance of each diffracted light from the optical axis AX at the pupil plane Ep. In the conventional projection type exposure apparatus shown in FIG. 11, the 0th-order diffracted light D ₀ passes near the optical axis AX. Therefore, r (0th order) = 0, while ± 1st order diffracted light D _P ,
D _m is r (first order) = M · λ / P (M is the magnification of the projection optical system). Therefore, the 0th-order diffracted light D ₀ and the ± 1st-order diffracted light D
_The wavefront aberration due to defocusing of _P and D _m is ΔF · M ² (λ
/ P) becomes a ^2/2.

On the other hand, in the exposure method and the projection type exposure apparatus according to the present invention, as shown in FIG.
_{Since 0} occurs in a direction inclined from the optical axis AX by the angle ψ, the distance of the 0th-order diffracted light component from the optical axis AX on the pupil plane Ep is r (0th) = M · sinψ. On the other hand, the distance of the -1st-order diffracted light component D _m from the optical axis on the pupil plane Ep is r
(−1 order) = M · sin (θ _m −ψ). And this time, if the _{sinψ = sin (θ m -ψ)} , 0 relative wavefront aberration becomes zero due to defocusing of the order diffracted light component D ₀ and -1-order diffracted light component D _m, from the wafer 16 is the focal position Even if the pattern 13 is slightly displaced in the optical axis direction, the image blur of the pattern 13 will not be as large as in the related art. That is, the depth of focus increases. Also, as shown in equation (3), s
Since in (θ _m −ψ) + sinψ = λ / P, the incident angle ψ of the illumination light beam L120 to the reticle 7 is related to the pattern of the pitch P by sinψ = λ / 2P (7) If so, it is possible to greatly increase the depth of focus.

When the pattern 13 is a pattern 201 composed of a light-shielding portion (Cr) and a light-transmitting portion whose periodic direction is one direction as shown in FIG. 8B, the relationship of the expression (7) is satisfied. As shown in FIG. 8E, the illumination light L120 has an incident angle such that the 0th-order diffracted light component 301A and the 1st-order diffracted light component 301B on the pupil plane Ep are distributed substantially equidistant from the optical axis AX.
, The pattern can be exposed with high resolution and a large depth of focus. Here, the secondary light source diameter of the pupil plane Ep (0-order diffracted light) is assumed to be 0.2 NA _R, this time, the center position of the optimal secondary light source with respect to the pattern 201 (0-order diffracted light) (optimal (The center position of the secondary light source in the periodic direction from a line segment perpendicular to the periodic direction including the optical axis AX) on the pupil plane Ep corresponding to the various incident angles is 0.8NA _R
It is assumed that In FIG. 8, (A), (B), (C)
Represents a one-dimensional or two-dimensional pattern,
(D), (E), and (F) show the effective pupil plane region Ep1 on the pupil plane Ep of the projection optical system 15. Further, XY assumed in the periodic direction (X, Y directions) of the pattern and the pupil plane Ep
It is assumed that the axis coincides with the axis.

By the way, the actual circuit pattern has many peripherals.
It is composed of a pattern with a direction. pattern
13 is a two-dimensional pattern having a predetermined fineness
Is taken as an example, the diffraction light is generated in two periodic directions.
(X, Y directions). Therefore, each of the two directions
There will be an optimum angle of incidence. These two periodic methods
Illumination light L120 is incident at the optimal incident angle in both directions
High resolution for 2D patterns
Exposure can be performed at a high depth of focus. For example, secondary
Center of light source (0th-order diffracted light component) in both X and Y directions
0.57NA_RPattern that satisfies equation (7) when placed in
Consider P1 (not shown). In this pattern P1
The center position of the secondary light source 300A is set in both X and Y directions.
0.57NA _RFig. 8 shows the situation when the components are arranged so that
It is shown in (D). 300B and 300C are the two dimensions at this time
The figure shows the first-order diffracted light from the pattern P1, and shows the 0th-order diffraction.
The light component and the first-order diffracted light component are almost apart from the optical axis AX on the pupil plane Ep.
They are distributed at equal distances. However, the pattern is good
In the case of miniaturization, both of the two periodicities
The relationship of the expression (7) cannot be satisfied.

For example, it is assumed that the pattern 200 in FIG. 8A forms a two-dimensional pattern at the same pitch as the pattern shown in FIG. 8B, and has a smaller pitch than the two-dimensional pattern P1. As shown in FIG. 8D, the two-dimensional pattern P
As in the case of 1, the center position of the 0th-order diffracted light component 300A is X, Y
If both illuminated so that 0.57NA _R for illumination light is diffracted by the pattern 200, one of the first-order diffracted light components due to the periodicity of the X-direction is generated in the position of 300A10, 1 by the periodicity in the Y direction One of the next-order diffracted light components will be generated at the position of 300A01. Therefore,
The 0th-order diffracted light component and the 1st-order diffracted light component are separated by the optical axis A at the pupil plane Ep.
It is not distributed at substantially the same distance from X.

Further, the first-order diffracted light components 300A10, 30
Only about 1/3 of the whole of 0A01 can pass through the pupil plane Ep1, so that the contrast of the image is reduced and the pattern cannot be resolved. Therefore,
A two-dimensional pattern 200 as shown in FIG.
As shown in (B) and (C), the image is decomposed into two pattern groups for each periodic direction. Then, as shown in FIGS. 8E and 8F, the zero-order diffracted light component (30
1A, 302A) and first-order diffracted light components (301B, 302A)
B) can be obtained individually when the illumination light L120 is incident on the pupil plane Ep so as to be distributed at substantially the same distance from the optical axis AX, so that a limit resolution and a maximum depth of focus can be obtained for each pattern. By sequentially performing overlapping exposure for each of the separation patterns, it is possible to obtain the maximum resolution and the maximum depth of focus over the entire circuit pattern.

When patterns 401 and 402 having different degrees of fineness coexist as shown in FIGS. 9A and 9B, conditions for satisfying the expression (7) differ depending on each pattern. Pattern 401 is zero-order central position of the diffracted light component is assumed to be pattern satisfying the expression (7) when in the 0.8 NA _R, patterns 402 when the 0 center position of the diffracted light component is in 0.57NA _R It is assumed that the pattern satisfies the expression (7).

[0025] When these two patterns 401 and 402 may have a mix, obtained by illuminating the zero center position of the diffracted light component 501A as shown in FIG. 9 (C) so as to be 0.8 NA _R, from the pattern 401 First-order diffracted light component 501B
And the 0th-order diffracted light component 501A are distributed substantially equidistantly from the optical axis AX on the pupil plane Ep. On the other hand, the first-order diffracted light component 501A1 and the zero-order diffracted light component 501A from the pattern 402 are not equidistant from the optical axis on the pupil plane Ep. Therefore, the depth of focus of the pattern 402 decreases.

Therefore, the pattern group is divided into two groups for each fineness, and these pattern groups are formed in two regions A and B on the same reticle as shown in FIG.
Then, separately for each pattern, FIG.
As shown in (D), the relationship of Expression (7) is satisfied, and the 0th-order diffracted light components (501A, 502A) and the 1st-order diffracted light components (501B, 502B) are substantially equidistant from the optical axis AX on the pupil plane Ep. When the illumination light L120 is incident on the reticle at an angle so as to be distributed, the maximum resolution and the maximum depth of focus can be obtained for each pattern.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing the overall configuration of a projection type exposure apparatus (stepper) suitable for an embodiment of the present invention. The illumination light beam generated from the mercury lamp 1 is reflected by the elliptical mirror 2 and is irradiated on the diffraction grating pattern 4 via a lens system 3 such as a relay system. The diffracted lights (for example, ± first-order lights) B1 and B2 generated from the diffraction grating pattern 4 are intensively incident on the two fly-eye lens groups 6A and 6B by the relay lens 5. At this time, the light source side focal planes 6a of the fly-eye lens groups 6A and 6B and the diffraction grating pattern 4 have a substantially Fourier transform relationship via the relay lens 5. In FIG. 1, the illumination light to the diffraction grating pattern 4 is illustrated as a parallel light beam. However, since it is actually a divergent light beam, the fly-eye lens groups 6A and 6B
The light beam incident on the light source has a certain size (thickness).

On the other hand, the reticle-side focal plane 6b of the fly-eye lens groups 6A and 6B is arranged in an in-plane direction perpendicular to the optical axis AX so as to substantially coincide with the Fourier transform plane (pupil conjugate plane) of the reticle pattern 13. Have been. The individual fly-eye lens groups 6A and 6B are independently movable in an in-plane direction perpendicular to the optical axis AX. The movement of the fly-eye lens groups 6A and 6B is held by the movable member 25, the details of which will be described later. The light source-side focal plane 6a and the reticle-side focal plane 6b of the fly-eye lens group naturally have a Fourier transform relationship. Therefore, in the case of the example of FIG. 1, the reticle-side focal plane 6b of the fly-eye lens group, that is, the exit surfaces of the fly-eye lens groups 6A and 6B have an image forming relationship (conjugate) with the diffraction grating pattern 4.

The luminous flux emitted from the reticle-side focal plane 6b of the fly-eye lens groups 6A and 6B is transmitted to the reticle stage by the optical system 107 including the condenser lenses 8, 10, and 11, the reticle blind 14, and the mirrors 9A and 9B. The reticle 7 on 17 is illuminated with a uniform illuminance distribution. The reticle blind 14 is composed of two L-shaped light shielding portions, and is arranged in a plane substantially conjugate with the reticle 7. The two light shielding units can be moved in a two-dimensional direction within a plane substantially conjugate with the reticle 7 by the blind driving unit 23. The reticle blind 14 defines an illumination area on the reticle 7. Reticle stage 17
Can be finely moved two-dimensionally by a motor or the like (not shown). The alignment between the reticle 7 and the optical axis AX is performed by a reticle alignment system 21, and the reticle 7 and the wafer 16 are aligned.
Is performed by a TTR (through-the-lens alignment) alignment system 22.

In this embodiment, the light-shielding member 12 is arranged, and the 0th-order diffracted light from the diffraction grating pattern 4 is cut off.
For this reason, the illuminating light illuminating the reticle pattern 13 emits light beams (2) emitted from the fly-eye lens groups 6A and 6B.
Only the light beam from the next light source image), and therefore the angle of incidence on the reticle pattern 13 is also limited to only the light beam (plurality) having the specific incident angle (plurality). An image of the diffraction grating pattern 4 is formed on the reticle-side focal plane 6b of the fly-eye lens 6, and the reticle pattern plane 13 and the reticle-side focal plane 11b of the fly-eye lens groups 6A and 6B.
, The illumination intensity distribution on the reticle 7 is not made non-uniform due to defects in the diffraction grating pattern 4 or dust. Also,
The diffraction grating pattern 4 itself does not form an image on the reticle 7 to degrade the illuminance uniformity. The diffraction grating pattern 4 is formed on a surface of a transmissive substrate, for example, a glass substrate.
The light-shielding film such as r may be patterned or a so-called phase grating in which a dielectric film such as SiO ₂ is patterned. In the case of a phase grating, the generation of zero-order diffracted light can be suppressed.

The diffracted light generated from the reticle pattern 13 on the reticle 7 thus illuminated is condensed and imaged by the telecentric projection optical system 15 in the same manner as described with reference to FIG. Pattern 1
The three images are transferred. The wafer 16 is mounted on a wafer stage 18 that moves in the X and Y directions. The wafer stage 18 is driven by a motor 19, and the position of the wafer stage 18 is detected by a laser interferometer IF. In addition, an off-axis type alignment system 20 is separately provided in the immediate vicinity of the projection optical system 15. The alignment of the entire wafer (wafer global alignment) is performed by the off-axis type alignment system 20.

In this embodiment, the entire pattern to be exposed is decomposed in accordance with the pattern arrangement direction and the fineness of the pattern, and exposure is performed using one or a plurality of reticles having a decomposed pattern. The diffraction grating pattern 4 is mounted on a moving table 24, and its pitch is adjusted so that the concentration position on the surface corresponding to the Fourier transform of the reticle pattern 13 or its vicinity (pupil surface) can be changed in accordance with each decomposition pattern. Can be exchanged for a different diffraction grating pattern 4a. Also, the diffraction grating pattern 4,
4a can be moved or rotated in an arbitrary direction within a plane perpendicular to the optical axis AX by a motor, a gear, or the like included in the movable base 24. Therefore, an arbitrary light quantity distribution can be created on the pupil plane.

The relay lens 5 may be a zoom lens system (such as an afocal zoom expander) composed of a plurality of lenses, and the focal position may be changed by changing the focal length. However, at this time, the diffraction grating pattern 4 and the focal plane 6a on the light source side of the fly-eye lens groups 6A and 6B should not be almost Fourier-transformed. The positions of the fly-eye lens groups 6A and 6B are adjusted in accordance with the pitch and directionality of the diffraction grating pattern 4. The fly-eye lens 6A is supported by a movable member 71A via a support rod 70A. The support rod 70A is extendable in the optical axis direction by driving elements such as a motor and a gear included in the movable member 71A. The movable member 71A itself is also movable along the fixed guide 72A, so that the fly-eye lens 6A is two-dimensionally movable in an in-plane direction perpendicular to the optical axis. Fly eye lens 6
Similarly, a support bar 70B and a movable member 7 (not shown)
1B, it is extendable and contractible in the optical axis direction, is movable along the fixed guide 72A, and is therefore two-dimensionally movable in a plane perpendicular to the optical axis. Therefore, the individual fly-eye lens groups 6A, 6B
Are independently movable in an in-plane direction perpendicular to the optical axis. Note that the number of fly-eye lens groups is not limited to two, and a plurality of fly-eye lens groups may be provided according to the decomposition pattern.
In this case, part of the fly-eye lens group can be retracted outside the effective pupil area (outside the pupil), and the fly-eye lens group is selected according to the light beam from the diffraction grating pattern 4. Unwanted fly-eye lens groups may be retracted outside the pupil.

The optical member for creating the light quantity distribution on the pupil plane includes:
The present invention is not limited to the diffraction grating pattern 4. For example, by rotating or vibrating a movable plane mirror, the light amount distribution on the pupil plane is changed with time, or the light amount distribution is concentrated at an arbitrary position on the pupil plane using a movable optical fiber, a mirror, a prism, or the like. It may be. Further, an opening (transmission part) may be provided in accordance with the fly-eye lens group positioned in accordance with the decomposition pattern using a spatial filter. This spatial filter may be located on either the light source side focal plane 6a or the reticle side focal plane 6b of the fly-eye lens group.

FIG. 2 shows a main control system 50 for controlling the entire apparatus shown in FIG. 1 and a name formed beside the reticle pattern 13 while the reticle 7 is being conveyed immediately above the projection optical system 15. , A keyboard 54 for inputting commands and data from an operator, and a drive system (motor, Gatoren, etc.) 56 for a movable member for moving the fly-eye lens groups 6A, 6B. ing. In the main control system 50,
Names of multiple reticles to be handled by this stepper,
Operation parameters of the stepper corresponding to each name (operation parameters relating to the decomposition pattern and the like) are registered in advance. In the present embodiment, when the bar code reader 52 reads the reticle bar code BC, the main control system 50 sets a diffraction grating corresponding to each of the pre-registered decomposition patterns as one of the operation parameters corresponding to the name. Information such as the pitch of the pattern 4, the movement and rotation position of the diffraction grating pattern 4, the movement position (position in the pupil conjugate plane) of the fly-eye lens groups 6 A and 6 B, the position of the reticle blind 14, etc. , Reticle blind drive system 2
3 and output to the drive system 56. Thereby, according to the decomposition pattern, the secondary light sources (the fly-eye lens groups 6A and 6A)
The position B and the illumination area are adjusted. The above operation can also be executed by the operator directly inputting commands and data from the keyboard 54 to the main control system 50. The main control system 50 includes an alignment system (20, 21, 2).
2), the stage drive system 19 and the interferometer IF are connected, and the entire apparatus is controlled overall.

By the way, each exit end area of the fly-eye lens group has a ratio of a numerical aperture of the emitted illumination light beam to the reticle 7 and a numerical aperture on the reticle side of the projection optical system 15, that is, a so-called σ value of 0.1 to 0. It is desirable to set the value to about 3. If the σ value is smaller than 0.1, the pattern fidelity of the transferred image is degraded, and if it is larger than 0.3, the effect of improving the resolution and increasing the depth of focus is weakened.

In order to satisfy the condition of the σ value (about 0.1 < σ < 0.3) determined by one of the fly-eye lens groups, the size of the exit end area of each of the fly-eye lens groups 6A and 6B must be large. By the way, (the size in the in-plane direction perpendicular to the optical axis) may be determined according to the illumination light flux (emission light flux). Also,
Reticle-side focal plane 6 of each fly-eye lens group 6A, 6B
Variable aperture stops may be provided in the vicinity of b, and the numerical aperture of the light beam from each fly-eye lens group may be variable. At the same time, a variable stop (NA limiting stop) is provided in the vicinity of the pupil (entrance pupil or exit pupil) of the projection optical system 15, and the N.A. A. Can also be varied to further optimize the σ value.

As described above, the position of the light amount distribution on the pupil plane (each position in a plane perpendicular to the optical axis of the fly-eye lens groups 6A and 6B) is determined (changed) according to the decomposition pattern to be transferred. Good to do. In this case, the position determination method is, as described in the section of operation, the optimum resolution and the depth of focus with respect to the pitch direction and fineness of each decomposition pattern to which the illumination light beam from each fly-eye lens group is to be transferred. The position (incident angle) at which light is incident on the reticle pattern may be set so as to obtain the effect of improving the above.

Next, a specific example of determining the position of each fly-eye lens group will be described with reference to FIGS. 3, 4A and 4B.
FIG. 3 is a diagram schematically showing a portion from the fly-eye lens groups 6A and 6B to the reticle pattern 13. The reticle-side focal plane 6b of the fly-eye lens group 6 matches the Fourier transform plane 12c of the reticle pattern 13. ing. At this time, a lens or a lens group that makes them have a Fourier transform relationship is represented as one lens 26. Further, it is assumed that the distance from the fly-eye lens-side principal point of the lens 26 to the reticle-side focal plane 6b of the fly-eye lens group 6 and the distance from the reticle-side principal point of the lens 26 to the reticle pattern 13 are both f.

FIG. 4A is a diagram showing an example of a partial pattern formed in the reticle pattern 13.
FIG. 5B is a diagram showing an optimum position of the center of the fly-eye lens group on the Fourier transform plane (or the pupil plane of the projection optical system) in the case of the reticle pattern of FIG. FIG. 4 (A)
Is a so-called one-dimensional line-and-space pattern in which transmissive portions and light-shielding portions are arranged in a band shape in the Y direction with the same width, and they are regularly arranged in the X direction at a pitch P.
At this time, the optimum position of each fly-eye lens group is shown in FIG.
As shown in (B), the position is an arbitrary position on the line segment Lα and the line segment Lβ in the Y direction assumed in the Fourier transform plane. FIG. 4B is a diagram of the Fourier transform surface 12c (6b) with respect to the reticle pattern 13 viewed from the optical axis AX direction, and the coordinate systems X and Y in the surface 12c are obtained by viewing the reticle pattern 13 from the same direction. 11 (A).
Now, from the center C through which the optical axis AX passes in FIG.
The distances α and β to the line segments Lα and Lβ are α = β, and λ
Is the exposure wavelength, α = β = f ・ (１ ／) ・ (λ
/ P). If these distances α and β can be expressed as f · sinψ, then sinψ = λ / 2P, which coincides with the numerical value described in the section of the operation. Accordingly, the center of each fly-eye lens group (the center of gravity of the light amount distribution of the secondary light source image formed by each fly-eye lens group) is located at the line segment Lα,
If it is on Lβ, two lines of 0th-order diffracted light and ± 1st-order diffracted light generated by the illumination light from each fly-eye lens with respect to the line and space pattern as shown in FIG. The diffracted light passes through a position that is approximately equidistant from the optical axis AX on the pupil plane Ep of the projection optical system. Therefore, as described above, the line and space pattern (FIG. 4)
The resolution and depth of focus for (A)) can be maximized. Similarly, for a pattern having periodicity in the Y direction, assuming line segments Lγ and Lε in the X direction, each position of the fly-eye lens group (each center of gravity of the light intensity distribution of the secondary light source image) is a line. It suffices that the distances are on the minutes Lγ and Lε.

Here, since the interval between the 0th-order light and the 1st-order light on the pupil plane is proportional to the fineness (pitch) of the pattern, a decrease in this interval means that a fine pattern cannot be resolved. Means Exposure with maximum resolution and maximum depth of focus by making illumination light incident on each decomposition pattern at the incident angle and incident direction corresponding to the position of the fly-eye lens group determined by the above conditions Can be.

FIG. 4 shows a reticle pattern 13.
Although only a pattern having periodicity in one direction as shown in (A) has been considered, other patterns may be focused on the periodicity (or fineness) and the periodic direction, and each of the fly-eye lens groups may be focused on. The center may be arranged. Here, reticle pattern 1
When 3 includes a two-dimensional periodic pattern, the first-order diffracted light component is generated in two directions. Then, the aforementioned line segments Lα, Lβ
In a pattern in which there is an intersection of the line segments Lγ and Lε, the center of each fly-eye lens group is arranged on this intersection, that is, either the + 1st-order diffracted light component or the −1st-order diffracted light component from the pattern By arranging the center of each fly-eye lens group at a position where two light beams, one and the zero-order diffracted light component, pass through an optical path that is almost equidistant from the optical axis AX on the pupil plane Ep in the projection optical system. An image of a two-dimensional pattern can be favorably formed. However, the method of matching the center position of the fly-eye lens with any one of the intersection points is such that the interval between the 0th-order and 1st-order diffracted light on the pupil plane is about 0.7 times the diameter of the circle of the pupil plane of the projection lens. Because of the limitation, the maximum resolution of the device cannot be set. Therefore, in order to obtain the maximum resolution, a multidimensional pattern having a plurality of pattern directions is decomposed for each pattern direction, and they are successively superimposed at the limit resolution that allows the maximum use of the diameter of the pupil of the projection lens. It is desirable to carry out. This division decomposes a pattern having a high spatial frequency component (fineness) in a plurality of directions so that the periodicity of the pattern having a spatial frequency component equal to or higher than a predetermined value is one direction on one reticle. . Under the above conditions, exposure can be performed with high resolution and high depth of focus.

In the example of the pattern shown in FIG. 4A, since the ratio (duty ratio) between the line portion and the space portion is 1: 1, ± 1st-order diffracted light is strong in the generated diffracted light. For this reason, attention has been paid to the positional relationship between one of the ± 1st-order diffracted lights and the 0th-order diffracted light. However, when the pattern is different from the duty ratio of 1: 1 or the like, the intensity of another diffracted light, for example, the ± 2nd-order diffracted light is increased. Therefore, the positional relationship between one of the ± 2nd-order diffracted lights and the 0th-order diffracted light is determined by the pupil plane Ep of the projection optical system.
May be substantially equidistant from the optical axis AX. The luminous flux emitted from each fly-eye lens group is
Each of them enters the reticle at an angle. At this time, if the direction of the center of gravity of the amount of light of these inclined incident light beams (plurality) is not perpendicular to the reticle, there is a problem that the position of the transferred image shifts in the in-plane direction of the wafer when the wafer 16 is slightly defocused. . To prevent this, the direction of the center of gravity of the light quantity of the illuminating light flux (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, the 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 15 is In this case, the vector sum of the product of the fly-eye lens group and the amount of light emitted from each fly-eye lens group may be set to zero. Also,
As a simpler method, the number of fly-eye lens groups is 2m (m is a natural number), and the positions of the m lenses are determined by the above-described optimization method (FIG. 10). What is necessary is just to arrange | position in the position symmetrical about the axis AX.

Further, for example, n devices (n is a natural number)
When the number of required fly-eye lens groups is m less than n,
The remaining (nm) fly-eye lens groups need not be used. In order to eliminate the use of the (nm) fly-eye lens groups, the light shielding member 12 may be provided at the positions of the (nm) fly-eye lens groups. At this time, it is preferable that the optical member that concentrates the illumination light at the position of each fly-eye lens group does not concentrate on the (nm) fly-eye lenses.

Next, an example of dividing the whole pattern into the decomposition patterns will be described. The whole pattern to be normally exposed is a line and space (L / S) pattern having some periodicity and fineness. A two-dimensional pattern as shown in FIG. 8 is decomposed into two parts for each periodic direction, or a pattern having the same periodic direction but different spatial frequency components (fineness) in one direction is used as shown in FIG. For example, a method of decomposing into two for each of the spatial frequencies can be considered. Also, the number of decompositions is not limited to two, and if the pattern has a certain or higher spatial frequency component in three or more directions, the number of pattern divisions is three. Further, FIG. 5 shows an example in which a whole pattern having periodicity in the X and Y2 directions and having two degrees of fineness with respect to the periodic pattern in the X direction is divided. It is shown that patterns having different periodic directions and fineness are decomposed into three types and formed on a reticle, respectively. Here, a reticle 7A on which a relatively wide L / S pattern PA1 in the X direction is formed, a reticle 7B on which a relatively narrow L / S pattern PA2 in the X direction is formed,
The patterns are respectively decomposed on the three reticles of the reticle 7C on which the L / S pattern PA3 in the Y direction is formed. The pattern PAG is a combined overall pattern obtained by sequentially performing overlay exposure (multiple exposure) using these three reticles.

If the number of decomposed patterns (reticles) is large, errors during overlapping exposure accumulate accordingly, which is disadvantageous in terms of throughput. Accordingly, as shown in FIG. 6, even in a two-dimensional pattern, as described in the operation section, the fineness is not so high, and a pattern PA4 satisfying the expression (7) in both directions and a pattern PA5 having a high fineness in one direction are mixed. If the pattern P
A4 is not divided for each period, and the pattern PA
4 and a pattern PA5.

The reticle 7 having the pattern 13 shown in FIG. 1 shows one of a plurality of decomposed patterns, and patterns 13a and 13b having a different arrangement direction and fineness from the pattern 13 are used. Reticle 7a. This exchange may be performed manually or may be performed by an automatic transport system. Each time the replacement is performed, the positioning is performed for each reticle. In addition, an interferometer may be provided on the reticle stage 17, and when the reticle is replaced, the reticle position may be adjusted by measuring the reticle position and the reticle rotation amount by the interferometer. In this case, if the value of the interferometer that has been aligned with the first one is stored, it is possible to perform alignment so that the value of the interferometer becomes the stored value when aligning the second and subsequent reticles. Can be.

Further, each of the decomposed patterns is formed on a separate reticle.
As disclosed in Japanese Patent No. 45730, each disassembled pattern is provided on one large glass substrate,
The reticle blind 14 can also adjust the illumination area for each decomposition pattern and perform exposure. Next, an example of the exposure method according to the present invention will be described. Here, as shown in FIG. 1, a pattern having a different direction is divided into patterns 13 and 13a and provided on two reticles 7 and 7a.
The number of reticles to be used (n = 2) is set as an initial value. [Step 100] The initial value of n is set to 0. [Step 101] Decomposition pattern pitch, periodic direction,
Information on the number of decomposition patterns and the like is read from a bar code provided for each reticle. [Step 102] A reticle having a decomposition pattern is placed on the reticle stage 17, and the reticle is aligned on the reticle stage using the reticle alignment system 21. [Step 103] Next, the opening shape and dimensions of the reticle blind 14 are adjusted to the decomposition pattern. [Step 104] Subsequently, the entire alignment of the wafer 16 is performed by the alignment system 20. If the exposure on the wafer 16 is the first print, step 104 is omitted. [Step 105] The TTR alignment system 22 performs alignment between the reticle 7 and the wafer 16. [Step 106] The diffraction grating pattern 4 and the fly-eye lens groups 6A and 6B are optimally set in accordance with the decomposition pattern, and the incident angle of the illumination light is determined. [Step 107] Exposure is performed. [Step 108] Set n = n + 1 and increment n. [Step 109] It is determined whether or not the number of reticles has reached the specified number (two). If Yes, the exposure is terminated. If No, the reticle is replaced and Step 101 is executed.

By the above steps, the optimum exposure can be performed for each of the decomposition patterns, and the composite pattern obtained by performing multiple exposure using each of the decomposition patterns is a pattern exposed under the optimum exposure condition. Becomes
Here, in the above steps, when the reticle 7 is replaced with the reticle 7a, that is, in the second step 106, the diffraction grating pattern 4 is rotated by 90 degrees in the direction of the arrow to generate the diffracted lights B1 and B2. By rotating the directions by 90 degrees, and by rotating the fly-eye lens groups 6A and 6B by 90 degrees around the optical axis AX, the illumination light beam can be optimized. At this time, if four fly-eye lens groups are provided as described above, the fly-eye lens group is moved along the optical axis A with the rotation of the diffraction grating pattern 4.
There is no need to rotate about X. Further, when the pattern 13a is a pattern having a different degree of fineness from the pattern 13 as shown in FIG. 9B, two of each of the decomposition patterns 13 and 13a are formed on the same reticle as shown in FIG. 9E. The reticle blind 14 may be used to divide the area into two areas A and B, and define the illumination areas of the areas A and B. In this case, the determination of n and the number in steps 100, 108, and 109 described above is the number of divisions. At this time, the second step 1
At 06, the diffraction grating pattern 4 does not rotate,
The diffraction grating pattern itself can be exchanged for one having a different pitch.

In the above embodiment, the light source is the mercury lamp 1
However, other bright line lamps, lasers (excimer, etc.), or light sources having a continuous spectrum may be used. Although most of the optical members in the illumination optical system are lenses, mirrors (concave mirrors, convex mirrors) may be used. Whether the projection optical system is a refraction system or a reflection system,
Alternatively, a catadioptric system may be used. In the above embodiment, a double-sided telecentric projection optical system is used, but a one-sided telecentric system or a non-telecentric system may be used. Furthermore, in order to use only light of a specific wavelength among the illumination light generated from the light source, a monochromatic unit such as an interference filter may be provided in the illumination optical system.

[0052]

As described above, according to the present invention, a fine pattern having periodicity in a plurality of directions and a fine pattern having a plurality of spatial frequency components, which cannot be resolved by the conventional method and apparatus, are resolved. Can be imaged. Also, the depth of focus can be increased for each decomposition pattern.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall configuration of a projection exposure apparatus according to one embodiment of the present invention;

FIG. 2 is a diagram showing a control system in the apparatus of FIG. 1;

FIG. 3 is a diagram schematically showing an optical path from an emission unit to a projection optical system;

FIG. 4A illustrates a one-dimensional reticle pattern.
(B) is a diagram for explaining the arrangement of the fly-eye lens exit portion on the pupil conjugate plane corresponding to the pattern of (A),

FIG. 5 is a view for explaining an example of dividing an entire pattern.

FIG. 6 is a view for explaining another example of dividing the entire pattern.

FIG. 7 is a view for explaining an exposure method according to one embodiment of the present invention;

FIGS. 8A, 8B, and 8C are diagrams showing a reticle pattern, and FIGS. 8D, 8E, and 8F show a zero-order diffracted light component and a first-order diffracted light component on a pupil conjugate plane corresponding to the reticle pattern. Diagram illustrating the distribution of

9A and 9B are diagrams showing a reticle pattern,
(C), (D) are diagrams illustrating the distribution of the 0th-order diffracted light component and the 1st-order diffracted light component on the pupil conjugate plane corresponding to the reticle pattern, and the patterns shown in (E), (A), and (B) are divided into two regions. Figure formed separately,

FIG. 10 is a view for explaining the principle of obtaining a high resolution and a high depth of focus according to the present invention;

FIG. 11 is a diagram illustrating a conventional technique.

[Explanation of symbols]

Reference Signs List 4 diffraction grating pattern 6 fly-eye lens 7 reticle 13, 13a, 13b reticle pattern 14 reticle blind 15 projection lens 16 wafer 17 reticle stage 24 moving table 25 moving member AX: optical axis, Ep: pupil plane

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (22)

(57) [Claims] 1. An entire pattern to be formed on a photosensitive substrate is divided into a plurality of decomposed patterns, illumination light is applied to each of the plurality of decomposed patterns via an illumination optical system, and the plurality of decomposed patterns are converted into the plurality of decomposed patterns. An exposure method for sequentially transferring a predetermined area on a photosensitive substrate, wherein a portion having a difference in fineness or a periodic direction in the entire pattern is converted into at least a first decomposition pattern and a second decomposition pattern. Decompose the illumination light passing through the surface equivalent to the Fourier transform of the first decomposition pattern to a position decentered from the optical axis of the illumination optical system according to the fineness of the first decomposition pattern or the periodic direction. A first exposure step of irradiating the first decomposition pattern with the illumination light being inclined with respect to the optical axis by concentrating the light on an area having: a surface corresponding to a Fourier transform of the second decomposition pattern By concentrating the passing illumination light in a region having a center at a position decentered from the optical axis according to the fineness of the second decomposition pattern or the periodic direction, the illumination light with respect to the optical axis A second exposure step of irradiating the second pattern in an inclined manner, wherein the first and second decomposition patterns are overlapped in the predetermined area. 2. The apparatus according to claim 1, wherein each of the first and second decomposition patterns is such that one of the zero-order diffraction light and ± n-order diffraction light generated from the decomposition pattern by the irradiation of the illumination light is substantially equidistant from the optical axis. The exposure method according to claim 1, wherein the exposure is performed so as to be distributed. 3. The exposure method according to claim 2 , wherein an incident angle of the illumination light with respect to a periodic direction of the decomposition pattern is substantially a half of a diffraction angle of the ± n order diffracted light . 4. An illumination optical system that divides an entire pattern to be formed on a photosensitive substrate into a plurality of decomposed patterns and irradiates illumination light to the decomposed patterns, and projects an image of the decomposed patterns onto the photosensitive substrate. An exposure apparatus comprising a projection optical system and sequentially transferring images of the plurality of separation patterns to a predetermined region on the photosensitive substrate, wherein, in the entire pattern, a portion having a difference in fineness or a periodic direction is used. Mask exchanging means for decomposing into at least two patterns and exchanging a first mask and a second mask each having the decomposed pattern individually; and in the illumination optical system, the first mask or the second mask is substantially Fourier-converted. The illumination light passing through a surface that is in a conversion relationship,
A light flux distribution shaping means for shaping a light quantity distribution having a local maximum value in at least two positions separated from each other; and the illumination by an amount determined by the fineness of the decomposition pattern or the periodic direction of the at least two local maximum values. Adjusting means for adjusting the light flux distribution shaping means so as to be set at discrete positions eccentric from the optical axis of the optical system, wherein the adjusting means controls the light amount distribution between the first mask and the second mask. An exposure apparatus characterized by differentiating. 5. A position adjusting means for adjusting a relative positional relationship between each of the first and second masks and the photosensitive substrate so that the decomposition patterns of the first and second masks overlap in the predetermined area. Claims further comprising:
5. The exposure apparatus according to 4 . 6. An illumination optical system that divides an entire pattern to be formed on a photosensitive substrate into a plurality of decomposed patterns and irradiates the decomposition pattern with illumination light, and projects an image of the decomposition pattern onto the photosensitive substrate. An exposure apparatus comprising a projection optical system and sequentially transferring images of the plurality of separation patterns to a predetermined region on the photosensitive substrate, wherein, in the entire pattern, a portion having a difference in fineness or a periodic direction is used. The mask and the irradiation area of the illumination light are separated into a plurality of patterns so that the different areas on the same mask on which at least two of the plurality of decomposition patterns are individually formed are sequentially irradiated with the illumination light. Changing means for changing the relationship between: the illumination light passing through a surface of the illumination optical system that is substantially in a Fourier transform relationship with the mask, at a maximum at at least two positions separated from each other; A light flux distribution shaping means for shaping into a light quantity distribution having, the at least two local maxima being decentered with respect to the optical axis of the illumination optical system by an amount determined according to the fineness of the decomposition pattern, or the periodic direction. Adjusting means for adjusting the light flux distribution shaping means so as to set the light flux distribution shaping means at discrete positions, wherein the adjusting means makes the light amount distribution different between the at least two decomposition patterns. 7. The apparatus according to claim 1, wherein the adjusting unit is configured to generate a zero-order diffracted light generated from the decomposition pattern by irradiation of the illumination light and a ± n-order diffracted light.
The exposure apparatus according to claim 4 or 6 , wherein the light amount distribution is adjusted so that one of the folded lights is distributed substantially equidistant from the optical axis. 8. A method of exposing a photosensitive substrate with illumination light applied to a mask via an illumination optical system, wherein a plurality of patterns are synthesized on the photosensitive substrate to form one pattern.
The plurality of patterns are finely aligned with each other to form a pattern.
At least first and second patterns having different fineness or periodic direction
Comprises over emissions, by irradiating the illumination light to the first pattern exposing the photosensitive substrate, substantially Fu and the pattern surface of said mask in said illumination optical system according to the second pattern
With changing the amount of light fraction <br/> distribution of the illumination light on the predetermined plane which is a relation of Fourier transform, exposing the photosensitive substrate by irradiating the illumination light in which the light amount distribution is changed to the second pattern An exposure method, comprising: 9. The exposure method according to claim 8 , wherein the illumination light has a light amount distribution on the predetermined surface which is enhanced outside the optical axis of the illumination optical system. 10. A method of exposing a photosensitive substrate with illumination light applied to a mask via an illumination optical system, wherein a pattern to be formed on the photosensitive substrate has a fineness or
Together into a plurality of patterns periodic direction is different, when the multiple exposure the photosensitive substrate by irradiating each said illumination light to said plurality of patterns, its said plurality of patterns
Each of the mask patterns in the illumination optical system corresponds to the
An exposure method characterized by changing a light amount distribution of the illumination light on a predetermined surface which has a relationship of a Fourier transform with the illumination surface. 11. The light source for changing the light amount distribution.
Claims characterized by exchanging an optical member in a bright optical system.
Item 10. The exposure method according to any one of Items 8 to 10 . 12. The optical member receives the illumination light and
Including a diffractive optical element that generates diffracted light
The exposure method according to claim 11 . 13. The diffractive optical element generates zero-order diffracted light.
13. The exposure method according to claim 12 , wherein the exposure method is a phase type that can be suppressed . 14. An illumination optical system comprising:
Placed on the entrance side of the optical integrator
The exposure method according to any one of claims 11 to 13, wherein the exposure method is performed. 15. An illumination light from a light source through an illumination optical system.
Irradiates the mask and is exposed to the illumination light through the mask
In a method of exposing a substrate, first and second patterns having different illumination conditions on the photosensitive substrate.
Form a single pattern by combining multiple patterns including
Illuminating each of the plurality of patterns to achieve
When irradiating light to perform multiple exposure on the photosensitive substrate,
In the bright optical system, the pattern surface of the mask is almost Fourier transformed.
The light amount distribution of the illumination light on a predetermined surface that is a replacement relationship,
The first pattern and the second pattern are different.
In order to make the illumination light incident on the illumination optical system and diffracted light
Replace the diffractive optical element that generates
Is used to enhance the light amount distribution on the predetermined surface outside the optical axis.
An exposure method , wherein a diffractive optical element is disposed in the illumination optical system . 16. The diffractive optical element includes the light source and the illumination.
Between the optical integrator in the optical system
The exposure method according to claim 15 , wherein the exposure is performed. 17. When the light amount distribution on the predetermined surface is changed,
Using a zoom lens system in the illumination optical system.
17. The exposure method according to claim 15, wherein the exposure method comprises: 18. An apparatus for irradiating a mask with illumination light from a light source and irradiating a photosensitive substrate with the illumination light through the mask, wherein a pattern surface of the mask is provided in the illumination optical system. And almost foo
The light amount of the illumination light on a predetermined surface which is related to the Rier transform
Illuminating light in the illumination optics to change the cloth
Means for replacing a diffractive optical element that generates diffracted light upon incidence
And first and second patterns having different illumination conditions on the photosensitive substrate.
Form a single pattern by combining multiple patterns including
When irradiating the plurality of patterns with the illumination light to perform multiple exposure on the photosensitive substrate ,
The light amount distribution in the first pattern is changed
The first diffractive optical element used for off-axis enhancement is
Being disposed in the illumination optical system, and in the second pattern,
The second diffractive optical element, which is different from the first diffractive optical element,
An exposure apparatus, which is disposed in a bright optical system. 19. The first and second diffractive optical elements each include:
It is a phase type that suppresses the generation of zero-order diffracted light.
19. The exposure apparatus according to claim 18 , wherein 20. The first and second diffractive optical elements are each
Optical integration in the light source and the illumination optical system.
19. A device according to claim 18, wherein the device is disposed between the radiator and the radiator.
Or the exposure apparatus according to 19 . 21. An illumination system according to claim 21, which is used for changing said light amount distribution.
And a zoom lens system arranged in the bright optical system.
The exposure apparatus according to any one of claims 18 to 20, wherein: 22. The illumination optical system according to claim 22, wherein the zoom lens system includes the illumination optical system.
Within the diffractive optical element and the optical integrator
The exposure apparatus according to claim 21 , wherein the exposure apparatus is disposed between the exposure apparatuses.