JP2000266640A - Aberration evaluation method - Google Patents

Abstract

(57) [Summary] To easily evaluate astigmatism and spherical aberration of a projection lens of an exposure apparatus. The wavelength of illumination light is λ, the numerical aperture of a projection lens is NA, the magnitude of the coherence factor of the illumination optical system is σ, the period of the reticle for aberration evaluation is P, and the aberration is reticle. When the reduction magnification of the evaluation reticle is m, 2 ^1/2 · λ / {NA (1-σ)} ≦ m · P ≦ 10
One having a two-dimensional periodic pattern arranged in a checkered lattice, satisfying the condition of ^1/2 · λ / {NA (1 + σ)} is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the aberration of a projection lens of an exposure apparatus, and more particularly to the method of evaluating the aberration of a projection lens of an exposure apparatus used for manufacturing a semiconductor device, in which it is difficult to remove the projection lens from the exposure apparatus. About the method.

[0002]

2. Description of the Related Art With the increase in the degree of integration of semiconductor devices, the position of a transfer pattern is distorted due to the aberration of a projection lens mounted on an exposure apparatus, and the focus changes within an exposure area.
Problems such as the occurrence of a focus difference depending on the direction of the pattern and the distortion of the shape of the pattern have gradually become apparent in the manufacture of semiconductor devices.

For this reason, in order to improve the performance of an exposure apparatus and predict the margin of a lithography process for the development of a semiconductor device in the future, it is essential to develop a technique for evaluating the aberration of a projection lens with high accuracy. .

Generally, a method using an interferometer is used for measuring the aberration of a lens. In this method, the lens body is incorporated in an interferometer, and the amount of aberration is measured from the distortion of the obtained interference fringes.

However, this evaluation method is based on the premise that the lens alone is removed, and cannot be implemented when it is difficult to remove the lens from the exposure apparatus main body.

Therefore, it is necessary to measure the aberration of a projection lens of an exposure apparatus used for manufacturing a semiconductor device in a state of being transferred. In such a case, the amount of aberration must be evaluated from the transfer pattern.

At present, various methods have been proposed as methods for measuring the projection lens aberration of an exposure apparatus, and are used for actual evaluation. Typical aberrations include spherical aberration, astigmatism, coma, curvature of field, and distortion.

As a method for evaluating coma, see Patent Application 1
[Japanese Patent Application No. 9-305917] is effective. This evaluation method is to measure a relative displacement amount after transfer generated due to coma aberration between a large pattern and a fine periodic pattern, and use the displacement amount as a measure of the coma aberration amount. is there.

Also, astigmatism and field curvature are described in Reference 1 [SPIE Vol. 1463 (199
1), p. 282] is effective.
In this evaluation method, since the astigmatism is a phenomenon in which the best focus position is shifted due to a difference in the direction of the pattern, the patterns arranged in four directions of the 0 degree direction, the 45 degree direction, the 90 degree direction, and the 135 degree direction are gradually reduced. The maximum value of the focus difference and the direction of astigmatism in two orthogonal directions are measured from the observation of the exposure pattern with the focus shifted. Also, 4
It is also applied to the measurement of field curvature by measuring the focus center in the direction over the entire exposure area.

On the other hand, if these aberration evaluation results are to be used for estimating a lithography process window by computer calculation or the like, it is necessary to represent the aberration evaluation results in association with a numerical expression in a definition based on any aberration expression method. .

As a method of evaluating aberrations focusing on this problem, the inventors of the present invention filed patent application 2 [Japanese Patent Application No. 10-3747].
3]. This is because, by selecting the illumination coherence at the time of exposure and the length of one cycle of the periodic pattern and performing the above-described aberration evaluation method and the like, it is possible to easily associate the wavefront aberration at a specific position of the lens with the aberration evaluation result. Becomes possible,
A quantitative measurement of the amount of aberration (total aberration of coma, spherical aberration and astigmatism) expressed by Zernike series expansion is realized.

When the aberration evaluation method disclosed in Japanese Patent Application Laid-Open No. H10-15064 is used, an odd function aberration represented by coma is measured as a lateral shift amount of the pattern without depending on the focus position, and the measurement sensitivity is also large. There is an advantage that it is not affected by the size.

However, even function aberrations, such as astigmatism and spherical aberration, require accurate measurement of the focus position. Therefore, there are difficulties in measuring even function aberrations for the following reasons. are doing.

When continuous exposure is performed in microsteps while gradually changing the focus position, and the best focus position is measured by a dark-field optical microscope, the exposure area becomes wider as the resolution of the focus is increased. However, the error in the focus position due to the curvature of field and the flatness of the wafer increases as the exposure area increases.

Further, when the best focus position is measured from the line width measurement by the length measuring SEM by reducing the number of exposures, it is necessary to increase the number of measurement points in order to improve the measurement accuracy because fitting to a quadratic function is required. , Measurement time becomes longer.

On the other hand, in the design of the projection lens of today's exposure apparatus, low-order aberrations are corrected by means of intentionally giving high-order aberrations. Therefore, in the evaluation of the aberration of the projection lens of today's exposure apparatus, it cannot be said that it is sufficient to accurately measure even the higher-order aberrations.

In order to evaluate low-order aberrations, it is necessary to measure the wavefront aberration around the projection lens. To this end, the finer the pattern, the more the diffracted light passes through the periphery of the projection lens and forms an image, so that measurement using a fine pattern is sufficient. Here, since the focus allowance for a fine pattern is narrow, when measuring the best focus position from the resolution of the pattern, highly accurate measurement is possible.

On the other hand, in order to evaluate higher-order aberrations, the wavefront aberration inside the projection lens must be measured. This requires measuring aberrations using a somewhat large pattern.

However, as the size of the pattern increases, the focus latitude sharply increases, so that the measurement of the best focus position using a large pattern tends to be extremely inaccurate. This makes it difficult to evaluate even function aberrations such as astigmatism and spherical aberration for which the focus position must be measured accurately.

[0020]

As described above, in the aberration evaluation of the projection lens of today's exposure apparatus, it was necessary to accurately measure even the higher-order aberrations. Since it was necessary to use a large pattern having a wide focus margin for evaluating the functional aberration, there was a problem that it was difficult to evaluate even functional aberration with high accuracy.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an aberration evaluation method capable of easily evaluating even functional aberration of a projection lens of an exposure apparatus. It is in.

[0022]

Means for Solving the Problems The gist of the present invention is to use a reticle for evaluating aberrations having a two-dimensional periodic pattern arranged in a checkerboard lattice satisfying a predetermined condition.

That is, in order to achieve the above object, the aberration evaluation method according to the present invention (claim 1) irradiates an illumination evaluation reticle arranged on a resist with illumination light via an illumination optical system. An aberration evaluation method for evaluating the aberration of a projection lens of the projection optical system by evaluating a transfer pattern transferred to the resist by a projection optical system corresponding to the aberration evaluation reticle, wherein When the wavelength is λ, the numerical aperture of the projection lens is NA, the magnitude of the coherence factor of the illumination optical system is σ, the period of the aberration evaluation reticle is P, and the reduction magnification of the aberration evaluation reticle is m. , As the aberration evaluation reticle, 2 ^1/2 · λ / {NA (1-σ)} ≦ m · P ≦ 10
It is characterized by using a pattern having a two-dimensional periodic pattern arranged in a checkered lattice satisfying the condition of ^1/2 · λ / {NA (1 + σ)}.

According to the study of the present inventors, as a reticle for aberration evaluation, predetermined conditions, that is, the wavelength of the illumination light is λ, the numerical aperture of the projection lens is NA, and the coherence factor of the illumination optical system is large Where σ is σ, the period of the aberration evaluation reticle is P, and the reduction magnification of the aberration evaluation reticle is m, 2 ^1/2 · λ / {NA (1-σ)} ≦ m · P ≦
^{10 1/2 · λ / {} NA (1 + σ)} satisfies the condition, the use of which has a checkered-arranged two-dimensional periodic pattern, as detailed in the following embodiments of the invention, It has been found that the even function aberration of the projection lens of the exposure apparatus can be easily evaluated from observation of the transfer pattern. Therefore, according to the aberration evaluation method according to the present invention using a reticle for aberration evaluation that satisfies the above predetermined condition,
The even function aberration of the projection lens of the exposure apparatus can be easily evaluated.

[0025]

Embodiments of the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 is a plan view showing an aberration evaluation reticle used for evaluating the aberration of a projection lens of a projection optical system of an exposure apparatus according to an embodiment of the present invention. FIG. 2 is a plan view showing a diffraction pattern on the resist when the resist is irradiated with illumination light of the illumination optical system of the exposure apparatus via the aberration evaluation reticle of FIG.

The diffracted light in the normal periodic pattern is distributed at regular intervals. However, the reticle for aberration evaluation shown in FIG. 1, that is, the diffracted light from the two-dimensional periodic pattern arranged in a checkerboard lattice has a specific diffraction order (m , N), the two-dimensional distribution is such that diffracted light exists only in a specific diffraction order as shown in FIG.

Therefore, by appropriately selecting the period (P) of the checkerboard lattice pattern with respect to the numerical aperture (NA) of the projection lens, a transfer pattern can be formed using only five diffracted lights. The conditions for forming a transfer pattern using only these five diffracted lights are in the range represented by the equation (1).

2 ^1/2 · λ / {NA (1-σ)} ≦ m · P ≦ 10 ^1/2 · λ / {NA (1 + σ)} (1) where λ is the wavelength of illumination light, NA is the numerical aperture of the projection lens, σ is the magnitude of the coherence factor of the illumination optical system, m is the reduction magnification of the aberration evaluation reticle, and P is the period of the aberration evaluation reticle. m · P indicates the period of the checkerboard lattice pattern transferred onto the resist. Hereinafter, the period m · P is simply referred to as period P.

FIG. 3 shows the relationship between the period P and the magnitude σ of the coherence factor. The shaded area in the figure is an area that satisfies the condition shown in Expression (1).

FIG. 4 schematically shows how the pattern is transferred when the condition of equation (1) is satisfied. In the figure, reference numeral 1 denotes a coherence factor of an illumination optical system, 2 denotes a reticle for evaluating aberration, 3 denotes an exit pupil of a projection lens, and 4 denotes a transfer pattern.

The first inequality in equation (1) is a condition that a part of the four diffracted lights other than the diffracted light passing through the center of the lens does not exist outside the lens numerical aperture. This is a condition that no diffracted light other than one diffracted light does not exist inside the lens numerical aperture.

For example, NA = 0.6, λ = 0.248μ
When σ is set to 0.3 in the exposure apparatus of m, P
When the checkerboard lattice pattern of which / 2 is 0.45 μm satisfies the condition of Expression (1) and σ is set to 0.15, P / 2
It can be understood that the checkerboard lattice patterns of 0.35 μm, 0.45 μm, and 0.55 μm satisfy the condition of Expression (1).

Since only five diffracted lights contribute to the image formation of the checkerboard lattice pattern represented by the condition of the equation (1) on the resist, the image is formed on the exit pupil 3 through which the five diffracted lights pass. It is considered that only the wavefront aberration in the five regions causes the pattern to be distorted and the position to be displaced upon imaging.

In particular, considering that the amount of wavefront aberration in a region passing by each diffracted light can be represented by the amount of wavefront aberration at the center position,
It is important for aberration evaluation to examine the relative relationship between the wavefront aberration amounts at these five points and the deformation state of the transfer pattern at that time.

For general aberration measurement, it is convenient to use an aberration expression using a Zernike polynomial. The Zernike polynomial is an orthonormal polynomial, and each term corresponds to each aberration. In addition, when various aberrations are complicatedly included like aberration in a general lens, there is an advantage that it can be expressed by a linear sum of each term.

In the Zernike polynomial, each aberration is represented by a circular amount (ρ, θ) on the exit pupil. For each order of θ, isotropic aberration (sequence of defocus + spherical aberration) and θ Aberration represented by a function (tilt + coma aberration series), aberration represented by a function of 2θ (series of astigmatism), a series of aberrations represented by a function of 3θ, a series of aberrations represented by a function of 4θ ... It can be divided into each series.

In particular, the term corresponding to defocus is represented by a parabolic quadratic surface relating to R, and the term corresponding to tilt representing parallel movement of the pattern is represented by an inclined surface.

Here, the relative relationship between the wavefront aberration amounts at the points where the above-mentioned five diffracted lights pass is examined. For example, if there is a spherical aberration, the wavefront aberrations at the five points are on an arbitrary parabolic surface. Also exists. That is, pattern deformation due to spherical aberration cannot be distinguished from pattern deformation at the time of defocus.

When coma exists, these five wavefront aberrations also exist on an arbitrary inclined surface. Therefore, coma can only be translated in the same way as tilt,
Do not deform the pattern.

In this way, when all the aberrations were examined, it was confirmed that all the aberrations other than the astigmatism series had an effect only by an action equivalent to either the defocus or the tilt. That is, the aberration that causes the pattern deformation to be abducted is only a series of astigmatism.

From the above examination, when a checkerboard lattice pattern satisfying the condition of equation (1) is transferred, the aberration that deforms the pattern is astigmatism only. Therefore, the checkerboard lattice pattern satisfying the condition of equation (1) is It can be said that this is suitable as a reticle for evaluating astigmatism aberration.

When the checkerboard lattice pattern is transferred using a positive resist, a hole pattern 5 as shown in FIG. 5 is formed. When the projection lens has astigmatism, the hole pattern 5 is deformed as shown in FIG. 6 with respect to the defocus amount.

Therefore, in the pattern exposed under the condition that the focus position is changed, the size of the hole pattern in the ± 45 ° direction is measured with respect to the direction in which the patterns are arranged, and the difference between the + 45 ° direction and the −45 ° direction is measured. Is confirmed, it can be confirmed that the projection lens has astigmatism.

Astigmatism expressed by the Zernike polynomial includes 0 ° / 90 ° astigmatism and + 45 ° as shown in FIG.
There are two types of astigmatism of ° / −45 °.

In the case of the checkerboard lattice pattern 6 inclined at 45 ° as shown in FIG. 8A, of the astigmatism, 0 ° /
Deformation occurs only for 90 ° astigmatism, + 45 °
It has been found that it is not affected by astigmatism of / −45 °. On the other hand, in the case of the checkerboard lattice pattern 7 as shown in FIG. 8B, the pattern deformation occurs only for + 45 ° / −45 ° astigmatism.

Therefore, by preparing the two types of checkerboard lattice patterns 6 and 7 shown in FIG. 8, the astigmatism of 0 ° / 90 ° and the astigmatism of + 45 ° / −45 ° are measured independently. It is possible to

Therefore, pattern deformation was actually predicted by computer calculation. At this time, the magnitude of the deformation was defined as the flatness ε as follows.

[0049] _{ε = (L +45 -L -45)} / (L +45 + L -45) ... (2) where, L _+45, L _-45, the diagonal of the transfer pattern as shown in FIG. 9 The dimensions.

FIG. 10 shows the defocus dependency of the deformation ratio as a calculation result. Z ₆ represents the magnitude of + 45 ° / −45 ° astigmatism. As described above, the flatness ε shows a linear change with respect to defocus, and the flatness ε becomes zero at the best focus. Further, even if the amount of aberration is the same, when the exposure amount is different, the inclination of the straight line is different.

The inclination of this straight line varies not only with the amount of exposure but also with the period of the checkerboard lattice pattern when four diffracted lights other than the diffracted light passing through the center of the lens protrude outside the exit pupil 3. I do.

However, when all of the five diffracted lights depend on the inside of the exit pupil 3, if the flattening ratio ε is normalized by the value shown by the equation (3), the exposure amount becomes as shown in FIG. It was found that the slope of the straight line was constant irrespective of.

｛(L ₊₄₅ + L ₋₄₅ ) / P ² ｝ ² (3) Note that ε ′ in FIG. 11 is the flattening factor after the standardization.

As described above, the checkerboard lattice satisfying the condition shown in the equation (1) is exposed with the defocus changed by two or more conditions, and the flatness at this time is measured. From the ratio, the amount of astigmatism can be obtained.

In the conventional method of measuring the best focus position from the upper limit focus position and the lower limit focus position where the pattern is separated and resolved, the focus position must be gradually changed in microsteps to continuously expose.

At this time, since the focus latitude is large for a large pattern, it is necessary to set a large amount of change in focus or increase the number of exposures in the conventional method. However, in this case, high-precision measurement is impossible because the measurement resolution is deteriorated or the focus position error due to the substrate flatness or the field curvature increases.

On the other hand, in the method for evaluating astigmatism based on the flattening ratio of the present embodiment, the astigmatism can be evaluated as the inclination of a straight line from the measurement result (the flattening ratio measurement result) for a small number of exposed patterns.

That is, from the measurement result of the flattening ratio, as shown in FIG. 12, a straight line intersecting with the horizontal axis is obtained at a position other than the origin, and the intersection is obtained from the inclination of the straight line. Is the amount of astigmatism. The best focus position can be obtained as the focus position when the oblateness becomes zero.

Since the flatness ratio has high sensitivity to astigmatism, the astigmatism amount and the best focus position obtained in this way have high values even when a large pattern is used. Further, in this evaluation method, since the amount of astigmatism is obtained from the difference ΔL between the intersection and the origin, there is an advantage that the focus error can be ignored.

On the other hand, when the spherical aberration is evaluated, first, two types of checkerboard lattice patterns having different periods, which satisfy the condition of equation (1), are prepared as aberration evaluation reticle. Next, for each of these checkerboard lattice patterns, the flatness is measured at at least two different focus positions, and a straight line indicating the focus position dependence of the flatness is obtained. Then, as shown in FIG. 13, the amount of spherical aberration is obtained from the difference ΔL ′ between the intersections of the two straight lines indicating the focus position dependence of these two flat rates with the horizontal axis (focus position).

The present invention is not limited to the above embodiment. For example, in the above embodiment, a case where a checkerboard lattice pattern formed in a square pattern is used as the aberration evaluation reticle has been described. The present invention is also effective when a checkered grid pattern formed of squares with rounded corners or a checkered grid pattern formed of circles shown in FIG. 15 is used. 14 and 15, FIG.
Both negative and positive patterns are shown. In addition, various modifications can be made without departing from the scope of the present invention.

[0062]

As described above in detail, according to the present invention, a projection reticle having a two-dimensional periodic pattern arranged in a checkered lattice satisfying a predetermined condition is used as a reticle for evaluating an aberration. Even function aberrations of the lens can be easily evaluated.

[Brief description of the drawings]

FIG. 1 is a plan view showing an aberration evaluation reticle according to an embodiment of the present invention.

FIG. 2 is a plan view showing a diffraction pattern on the resist when the resist is irradiated with illumination light of an illumination optical system of the exposure apparatus via the aberration evaluation reticle of FIG.

FIG. 3 is a diagram showing a relationship between a period P and a magnitude σ of a coherence factor.

FIG. 4: 2 ^1/2 · λ / {NA (1-σ)} ≦ P ≦ 10
^The figure which shows typically the mode of pattern transfer when the conditions of ^1/2 * (lambda) / {NA (1 + σ)} are satisfied.

FIG. 5 is a view showing a transfer pattern of a checkerboard lattice pattern transferred to a positive resist.

FIG. 6 is a view showing a transfer pattern of a checkerboard lattice pattern transferred to a positive resist when astigmatism exists in the projection lens;

FIG. 7 is a diagram showing types of astigmatism expressed by Zernike polynomials.

FIG. 8 only for 0 ° / 90 ° astigmatism and +
A diagram showing a checkerboard lattice pattern in which pattern deformation occurs only for 45 ° / −45 ° astigmatism

FIG. 9 is a view showing two orthogonal dimensions of a transfer pattern used for defining the flatness ε;

FIG. 10 is a diagram showing the defocus dependency of the deformation ratio ε.

11 is a diagram showing a defocus dependence of _{{(L +45 + L -45)} / P 2} aspect ratio that is standardized by ² epsilon '

FIG. 12 is a diagram for explaining a method of obtaining an astigmatism amount and a best focus position from a measurement result of an oblateness;

FIG. 13 is a diagram for explaining a method for evaluating spherical aberration according to the present invention.

FIG. 14 is a diagram showing a modified example of the aberration evaluation reticle.

FIG. 15 is a diagram showing another modified example of the aberration evaluation reticle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Coherence factor 2 ... Rectile for aberration evaluation 3 ... Emission pupil 4 ... Transfer pattern 5 ... Hole pattern 6,7 ... Checkered lattice pattern

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G086 FF06 HH06 2H095 BB02 BB31 BB36 5F046 AA18 AA25 CB12 CB17 DA13 DB05

Claims (6)

[Claims] An illumination optical system irradiates an illuminating reticle disposed on a resist with illumination light through an illumination optical system, and a transfer pattern transferred to the resist by a projection optical system corresponding to the aberration evaluating reticle. A method for evaluating aberration of a projection lens of the projection optical system by evaluating the wavelength of the illumination light and the numerical aperture of the projection lens.
A, when the magnitude of the coherence factor of the illumination optical system is σ, the period of the aberration evaluation reticle is P, and the reduction magnification of the aberration evaluation reticle is m, the aberration evaluation reticle is 2 ^{1 / 2} · λ / ｛NA
(1−σ)｝ ≦ m · P ≦ 10 ^1/2 · λ / ｛NA (1+
σ) A method for evaluating aberrations, which uses a pattern having a two-dimensional periodic pattern arranged in a checkered lattice satisfying the condition of｝. 2. A reticle for aberration evaluation disposed on a resist is irradiated with illumination light via an illumination optical system, and a transfer pattern transferred to the resist by a projection optical system corresponding to the reticle for aberration evaluation is provided. A method for evaluating aberration of a projection lens of the projection optical system by evaluating the wavelength of the illumination light and the numerical aperture of the projection lens.
A, when the magnitude of the coherence factor of the illumination optical system is σ, the period of the aberration evaluation reticle is P, and the reduction magnification of the aberration evaluation reticle is m, the aberration evaluation reticle is 2 ^{1 / 2} · λ / ｛NA
(1−σ)｝ ≦ m · P ≦ 10 ^1/2 · λ / ｛NA (1+
σ) By using a pattern having a two-dimensional periodic pattern arranged in a checkered lattice satisfying the condition of｝, and determining two orthogonal dimensions of the transfer pattern, the astigmatism of the projection lens can be reduced. An aberration evaluation method characterized by evaluating the presence or absence. 3. A reticle for aberration evaluation disposed on a resist is irradiated with illumination light via an illumination optical system, and a transfer pattern transferred to the resist by a projection optical system corresponding to the reticle for aberration evaluation is provided. A method for evaluating aberration of a projection lens of the projection optical system by evaluating the wavelength of the illumination light and the numerical aperture of the projection lens.
A, when the magnitude of the coherence factor of the illumination optical system is σ, the period of the aberration evaluation reticle is P, and the reduction magnification of the aberration evaluation reticle is m, the aberration evaluation reticle is 2 ^{1 / 2} · λ / ｛NA
(1−σ)｝ ≦ m · P ≦ 10 ^1/2 · λ / ｛NA (1+
σ) The one having a two-dimensional periodic pattern arranged in a checkered lattice satisfying the condition of｝ is used, and from the relationship between a plurality of different focus positions and the flatness of the transfer pattern at these focus positions, An aberration evaluation method characterized by quantitatively evaluating astigmatism caused by a projection lens. 4. The aberration evaluation method according to claim 3, wherein the astigmatism caused by the projection lens is quantitatively evaluated from a slope of a straight line obtained from the focus position and the flatness at the focus position. . 5. An illumination optical system for irradiating first and second aberration evaluation reticles disposed on a resist with illumination light through an illumination optical system, and a projection optical system corresponding to these aberration evaluation reticles. A method of evaluating the aberration of the projection lens of the projection optical system by evaluating the transfer pattern transferred to the projection optical system, wherein the wavelength of the illumination light is λ, and the numerical aperture of the projection lens is N
A, the magnitude of the coherence factor of the illumination optical system is σ, the period of the first aberration evaluation reticle is P1, the period of the second aberration evaluation reticle is P2, and the first aberration evaluation reticle is P2. When the reduction magnification is m1 and the reduction magnification of the second aberration evaluation reticle is m2, ^21/2 · λ /
{NA (1-σ)} ≦ m1 · P1 ≦ 10 ^1/2 · λ / ｛N
A reticle having a two-dimensional periodic pattern arranged in a checkered lattice satisfying the condition of A (1 + σ)｝ is used as the second aberration evaluation reticle, 2 ^1/2 · λ /
{NA (1-σ)} ≦ m2 · P2 ≦ 10 ^1/2 · λ / ｛N
A pattern having a two-dimensional periodic pattern arranged in a checkered grid satisfying the condition of A (1 + σ) か ら is used, and a relationship between a plurality of different focus positions and the flatness of a transfer pattern at these focus positions A method for quantitatively evaluating spherical aberration caused by the projection lens. 6. When the focus position is on the vertical axis and the flatness is on the horizontal axis, the focus position and the flatness of the transfer pattern corresponding to the first aberration evaluation reticle among the transfer patterns at the focus position are obtained. From the difference between the intersection of the straight line with the horizontal axis and the intersection of the straight line obtained from the focus position and the flattening rate of the transfer pattern at the focus position corresponding to the second aberration evaluation reticle, 6. The aberration evaluation method according to claim 5, wherein spherical aberration caused by the projection lens is quantitatively evaluated.