JPH10176974A - Method for measuring aberration of projecting optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately measure the amount of an aberration by projecting an image of a mask patterned with either a line-and-space pattern (L/S) or an isolated line pattern included onto a resist of a substrate and measuring the amount of a positional shift of an image of the L/S or isolated line pattern formed on the substrate. SOLUTION: A first and a third groups L/S are patterned to patterns 103 and 102, thereby forming a mark group 101. A second and a fourth groups L/S are patterned to patterns 106 and 105 thereby forming a mark group 104. That is, reference patterns 102, 105 are formed at an upper half and comparison patterns 103, 106 are formed at a lower half of the respective mark groups 101, 104. A mask 100 is arranged to a projecting optical system an aberration of which is to be measured and, exposed onto a photosensitive substrate so that the mark groups 101, 104 overlap. When the exposed substrate is developed, a resist image of an overlapping part remains on the substrate. The resist image of the reference pattern and comparison pattern is measured, whereby the amount of a shift is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the measurement of aberration of a projection optical system, and more particularly to the measurement of aberration of a projection optical system of a projection type exposure apparatus used for manufacturing a semiconductor device or a liquid crystal display device.

[0002]

2. Description of the Related Art As circuit patterns of semiconductor elements and the like increase in miniaturization year by year as the degree of integration increases, a projection type exposure apparatus that resolves this pattern also needs to cope with miniaturization.
An exposure apparatus having a shorter exposure wavelength from 365 nm to 248 nm has been required. Accordingly, it has been required that various aberrations of the projection optical system of these exposure apparatuses be considerably reduced.

The measurement of the asymmetric aberration of the conventional projection lens (including the coma aberration of the projection lens and the coma aberration due to the eccentricity between the mechanical center of the projection lens and the optical axis) is performed in a state where the projection lens is arranged in the projection exposure apparatus. Then, a light-shielding pattern is provided in the light transmitting portion on the reticle, and transferred to a resist-coated substrate,
The asymmetric amount of the transferred pattern resist image is inspected using an electron microscope or the like.

[0004]

However, in order to inspect the asymmetry amount of the resist image, a measuring device having a resolution of about 0.005 μm is required. (SEM) only. However, there is a problem that the resolution of the SEM changes depending on the optical axis alignment of the electron optical system and the internal gas pressure, that is, the degree of vacuum, and there is a difference in the resolution due to individual differences between workers and the state of the apparatus. The difference in resolution has a large effect on the measured aberration amount.

Accordingly, an object of the present invention is to measure the amount of aberration of a projection optical system at high speed and with high accuracy without using a complicated microscope.

[0006]

In order to achieve the above object, an aberration measuring method according to the present invention is an aberration measuring method for measuring the amount of aberration of a projection optical system, and comprises a line and space pattern (L / S). And disposing a mask provided with a pattern including any one of an isolated line pattern in an optical path of the projection optical system; and disposing a resist-coated substrate at a projection position of the projection optical system; and Projecting the resist on the substrate by the projection optical system to expose the resist, developing the exposed substrate, and forming an image of a line-and-space pattern by the resist formed on the substrate by the developing process. Or measuring the amount of displacement of the position of the image of the isolated line pattern.

Also, there is provided an aberration measuring method for measuring the amount of aberration of a projection optical system, wherein the first pattern including one of a line-and-space pattern and an isolated line pattern having a predetermined line width WA; Disposing a mask provided with a line-and-space pattern having a different predetermined line width WB and a second pattern including any one of the isolated line patterns in the optical path of the projection optical system; Arranging a substrate at a projection position of the projection optical system, projecting each pattern on the mask onto a resist of the substrate by the projection optical system and exposing the same, and developing the exposed substrate And a line of the image of the first pattern formed by the resist formed on the substrate by the developing step.
Measuring the amount of positional deviation between the line of the pattern image and the line of the pattern image.

Further, the mask may be provided so that each line of the first and second patterns is parallel to each other.

In this case, aberration can be measured by measuring the amount of positional shift of the image of the line-and-space pattern or the isolated line pattern formed on the substrate.

The aberration measuring method according to the present invention is an aberration measuring method for measuring the amount of aberration of a projection optical system, wherein the first method includes one of a line-and-space pattern having a predetermined line width WA and an isolated line pattern. A pattern, a second pattern including one of a line-and-space pattern having a predetermined line width WB different from the line width WA and an isolated line pattern;
Disposing a mask provided with a line-and-space pattern having the predetermined line width WB and a third pattern including any one of the isolated line patterns in an optical path of the projection optical system; Disposing at a projection position of the projection optical system, projecting each pattern on the mask onto a resist of the substrate by the projection optical system and exposing the same, and developing the exposed substrate. The amount of positional deviation between the image line of the first pattern and the image line of the second or third pattern due to the resist formed on the substrate by the developing step is determined by the second Correcting and measuring based on the positions of the lines of the image of the pattern and the lines of the image of the third pattern.

With this configuration, it is possible to correct the positional deviation of the image measured to know the aberration with reference to the second and third patterns.

Here, the mask may be provided so that the lines of the first, second, and third patterns are parallel to each other.

The aberration measuring method according to the present invention is an aberration measuring method for measuring the amount of aberration of a projection optical system, and includes a first line-and-space pattern having a predetermined line width WA and an isolated line pattern. Pattern and predetermined line width W
Disposing a first mask on which a second pattern including any one of the line-and-space pattern B and the isolated line pattern is provided in the optical path of the projection optical system; A second mask including a third pattern including one of a space pattern and an isolated line pattern and a fourth pattern including one of a line-and-space pattern having the predetermined line width WB and an isolated line pattern is provided. Arranging a substrate coated with a resist at a projection position of the projection optical system, a step of arranging a substrate coated with a resist at a projection position of the projection optical system, and a step of arranging a pattern on the second mask. Projecting the resist onto the substrate by the projection optical system to expose the resist, developing the exposed substrate, and developing the resist formed on the substrate by the developing step. The amount of positional deviation between the image line of the first pattern and the image line of the third pattern is determined by the position of the image line of the second pattern and the image line of the fourth pattern. And measuring based on the correction.

With this configuration, the images of the second and fourth patterns can be used for correcting the amount of displacement between the images of the first and third patterns for measuring aberration.

Here, the lines of the first and second patterns are parallel to each other on the mask, and the third and fourth lines are
And the step of projecting and exposing may include the step of arranging each mask such that each line of each pattern of each mask is parallel to each other. Good.

Further, the aberration measuring method according to the present invention is an aberration measuring method for measuring the amount of aberration of the projection optical system, wherein the first measuring point intersects an arbitrary virtual reference line LA0 at an angle α of less than 45 degrees.
A first line-and-space pattern formed of lines having a predetermined line width WA, each line being arranged in parallel and line-symmetrically with respect to the virtual center line, and the virtual reference line LA0
A predetermined distance LN1 from the intersection XA of the first virtual center line
Each line is formed in parallel with the second virtual center line intersecting at an angle -α at a point YA on a virtual reference line LA0 separated by a line with the predetermined line width WA. And a virtual reference line LA separated by the predetermined distance LN1 from the intersection YA.
A third line and a line having the predetermined line width WA, each line being arranged in parallel and line-symmetrically with a third virtual center line intersecting at an angle α at a point ZA on zero The first, second and third line and space patterns form a zigzag pattern. A step of placing it inside,
A fourth line formed of a line having a predetermined line width WB in which each line is arranged parallel and line-symmetrically with a fourth virtual center line that intersects with an arbitrary virtual reference line LB0 at an angle -α of less than 45 degrees. 4 and a point YB on the virtual reference line LB0 separated by a predetermined distance LN2 from the intersection XB of the virtual reference line LB0 and the fourth virtual center line.
A fifth line-and-space pattern formed by the line having the predetermined line width WB, wherein each line is arranged in parallel and line-symmetrically with respect to a fifth virtual center line intersecting with the fifth virtual center line; The predetermined line width WB, wherein the respective lines are arranged in parallel and line-symmetrically with a sixth virtual center line intersecting at an angle -α at a point ZB on a virtual reference line LB0 separated by a predetermined distance LN2. And a sixth line-and-space pattern formed by the fourth, fifth and sixth lines.
A line and space pattern is forming a zigzag pattern, a step of arranging the other mask on which the second group of line and space patterns have been applied in the optical path of the projection exposure system, and a substrate coated with a resist. Disposing at a projection position of the projection optical system, and a first group of line and space patterns on the one mask and a second group of line and space patterns on the other mask, A step of projecting and exposing the resist on the resist, a step of developing the projected substrate, and a first group of line and space images and a second group of resist formed on the substrate by the developing step. Measuring the positional deviation between the lines of the line-and-space image using a moiré mark.

According to this structure, since the line and space images of the first and second groups are in a zigzag pattern, the positional displacement between the images can be enlarged using a moire mark without using a complicated microscope. Can be measured accurately.

Further, the virtual reference line LA is located at a position different from the line and space pattern of the first group.
A virtual reference line L parallel to 0 and at a predetermined distance LN11
A predetermined line width W in which each line is arranged parallel and line symmetric with respect to a seventh virtual center line intersecting C0 at an arbitrary angle β.
And a virtual reference line L separated by a predetermined distance LN3 from an intersection XC of the seventh line-and-space pattern formed by the line C and the virtual reference line LC0 and the seventh virtual center line.
An eighth line formed by the line having the predetermined line width WC, wherein the respective lines are arranged in parallel and line-symmetrically with an eighth virtual center line intersecting at an angle -β at a point YC on C0. Each line is arranged in parallel and line-symmetrically with a ninth virtual center line that intersects with the and space pattern at a point ZC on the virtual reference line LC0 separated by the predetermined distance LN3 from the intersection YC at an angle β. A ninth line and space pattern formed of lines having the predetermined line width WC, wherein the seventh, eighth, and ninth line and space patterns form a zigzag pattern. A step of arranging one mask in the optical path of the projection exposure system on which the three groups of line and space patterns have been applied, and further, the third group at a position different from the line and space pattern of the second group. The Rhine And a fourth group of line-and-space patterns that are line-symmetric with respect to the virtual reference line LC0 and the virtual reference line LD0 that is parallel to the virtual reference line LB0 and at a predetermined distance LN12. Arranging the other mask in the optical path of the projection exposure system, wherein
The step of measuring the positional deviation between the lines of the first group of line and space images and the second group of line and space images using a moiré mark includes the third group of line and space pattern images and The method may include a step of performing measurement by correcting the moire mark with the image of the four groups of line and space patterns.

With this configuration, the positional deviation between the lines of the first group line-and-space image and the second group line-and-space image is corrected by the third group line-and-space image and the fourth group. It can be measured by correcting the moire mark with the image of the line and space pattern.

Here, if the distance LN11 and the distance LN12 are set equal, the correction can be made easily.

Further, in the mask according to the present invention, each line is arranged in parallel and line-symmetrically with respect to a first virtual center line which crosses an arbitrary virtual reference line LA0 at an angle α of less than 45 degrees.
A first line-and-space pattern formed by a line having a predetermined line width WA and a virtual reference line LA0 separated by a predetermined distance LN1 from an intersection XA between the virtual reference line LA0 and the first virtual center line. The second crossing at an angle -α at point YA
A second line formed of the line having the predetermined line width WA, wherein each line is arranged in parallel and line symmetrically with respect to the virtual center line
Each line is parallel and line symmetric with a third virtual center line that intersects with the line and space pattern at an angle α at a point ZA on a virtual reference line LA0 separated by the predetermined distance LN1 from the intersection YA. The predetermined line width W
A third group of line-and-space patterns including a third line-and-space pattern formed by the line A, wherein the first, second, and third line-and-space patterns form a zigzag pattern. It has been subjected.

With this configuration, it can be used for a method of measuring the amount of aberration of the projection optical system.

Also, a set of masks according to the present invention is such that each line is parallel to a fourth virtual center line that intersects the aforementioned mask with an arbitrary virtual reference line LB0 at an angle -α of less than 45 degrees. A fourth line-and-space pattern formed by symmetrically arranged lines having a predetermined line width WB and a predetermined distance LN2 from an intersection XB between the virtual reference line LB0 and the fourth virtual center line. Point YB on virtual reference line LB0
A fifth line-and-space pattern formed by the line having the predetermined line width WB, wherein each line is arranged parallel and line-symmetrically with respect to a fifth virtual center line intersecting at an angle α at A sixth intersection at an angle -α at a point ZB on a virtual reference line LB0 separated by the predetermined distance LN2 from the intersection YB.
The sixth line formed by the line having the predetermined line width WB, in which each line is arranged in parallel and line symmetrically with respect to the virtual center line
And a second mask provided with a second group of line and space patterns, wherein the fourth, fifth, and sixth line and space patterns form a zigzag pattern. .

Such a set of masks can be used for forming a superimposed image for measuring the aberration of the projection optical system.

Further, at a position different from the line and space pattern of the first group, a seventh line which is parallel to the virtual reference line LA0 and intersects the virtual reference line LC0 at a predetermined distance LN11 at an arbitrary angle β. A seventh line-and-space pattern formed by a line having a predetermined line width WC in which each line is arranged in parallel and line-symmetrically with respect to the virtual center line, and the virtual reference line LC0 and the seventh virtual center Each line is arranged in parallel and line-symmetrically with an eighth virtual center line that intersects at an angle -β at a point YC on the virtual reference line LC0 separated by a predetermined distance LN3 from the intersection XC with the line, An eighth line-and-space pattern formed by the line having the predetermined line width WC, and the predetermined distance LN from the intersection YC.
Each line is parallel and line-symmetric with respect to a ninth virtual center line intersecting at an angle β at a point ZC on a virtual reference line LC0 separated by 3 and is formed by the line having the predetermined line width WC. A third group of line and space patterns including a ninth line and space pattern, wherein the seventh, eighth, and ninth line and space patterns form a zigzag pattern. .

At this time, the third group of line and space patterns can be used for correction when measuring the amount of aberration of the projection optical system.

Further, a fourth group of line and space patterns symmetrical with respect to the virtual reference line LC0 at a position different from the second group of line and space patterns. However, the other mask may be provided so that the virtual reference line LC0 substantially coincides with the virtual reference line LD0 that is parallel to the virtual reference line LB0 and at a predetermined distance LN12.

At this time, the line and space patterns of the third and fourth groups can be used for correction when measuring the aberration amount of the projection optical system.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle of the present invention and an apparatus suitable for carrying out the present invention will be described with reference to FIGS.

FIG. 13 is a diagram showing an example of a pattern on a photomask and an aerial image intensity distribution of the pattern. This (a) is a dark line pattern (called a positive pattern) in which five light-shielding portions made of chrome lines of a certain width are drawn on a light transmitting portion on a reticle such as a glass substrate (quartz) as a reticle (mask) pattern. FIG. The reticle pattern includes a light-line pattern (called a negative pattern) in which a light-shielding portion is formed on a glass substrate with chrome or the like, and five light-transmitting portions formed of glass lines from which chrome is peeled off at a certain width are drawn. And and space pattern.

Here, in general, the line and space pattern is a light-shielding portion having a predetermined line width, and a plurality of straight line segments (lines) parallel to each other and a non-linear portion having a predetermined width. It can be defined as a pattern that is separated by an interval (space) that is a light shielding portion. Normally, the width of the line and the interval between the non-light-shielded portions are formed to be substantially the same. This is a positive pattern, and the negative pattern is a pattern in which a light-shielding part and a non-light-shielding part of the positive pattern are interchanged. A simple line and space pattern includes both positive and negative patterns.

FIG. 2B shows a method of, for example, 1.7 on a photomask.
It is assumed that the light distribution pattern of 5 μm has an intensity distribution on a photomask. This pattern is defined by the numerical aperture (N
A) is 0.60 and the coherency of the illumination optical system (σ
Value) was 0.36 using an exposure apparatus having a wavelength of 365 n.
The ideal aerial image intensity distribution when the light beam of m (i-line) is projected onto the transfer object is as shown in FIG. 13C, and the ideal intensity distribution (shown in FIG. 13B). And the actual intensity distribution are superimposed. This is the case where the aberration is zero.

Further, for example, when the coma aberration amount is x
If it is set to μm, the result is as shown in FIG. 9D, and it can be seen that the aerial image intensity when projected on the object to be transferred is displaced (ΔX) with respect to the intensity distribution on the mask. Here, FIG. 13 is not a diagram of the actual aerial image intensity distribution but a diagram for explanation.

FIG. 14A shows an image forming position of the transfer object when the pattern size on the transfer object is changed when the coma aberration amount of the projection lens is, for example, 0.6 μm. It is. As can be seen from this figure, even if the coma aberration amount is the same, the image formation position is different when the pattern size of the transferred object changes.

FIG. 14B shows that the pattern size of, for example, an object to be transferred is set to 0.35 μm (pattern A) by the projection lens.
FIG. 9 is a diagram showing image forming positions when the coma aberration amount is changed between 0.70 μm and 0.70 μm (pattern B). This figure shows that the amount of image position shift is determined for various known coma aberrations (eg, 0.2,
0.4, 0.6, 0.8) and measure and plot. For example, FIG. 14A is a diagram showing an image forming position shift amount when the aberration is 0.6. From this, the image forming position shift amount when the pattern line width is 0.35 and 0.7 is read. , Are 0.12 and 0.07, respectively. When the image position deviation amount read from the pattern line width-image position deviation amount diagram created for each aberration amount in this way is plotted on the aberration amount-image position deviation amount diagram, FIG. can get.

It can be seen from this figure that as the amount of coma increases, the amount of deviation between the image forming positions of pattern A and pattern B increases. Pattern A
It can be seen that the difference between the imaging position deviation amount of the pattern B and the pattern B becomes large. That is, even if the absolute value of the shift amount of each pattern cannot be measured, the coma aberration amount can be obtained by combining the pattern A and the pattern B and measuring the difference between the image formation position shift amounts.

The patterns A and B may have the same line width.
It is preferable to provide a phase shift pattern as described in detail in FIG.

According to the present invention, such a deviation amount of the image forming position is obtained.
Alternatively, the aberration is measured using the difference in the amount of deviation of the imaging position depending on the nature of the line (width, isolated line or plural lines).

One example of a combination of patterns applied on a mask used in the present invention is shown in FIG. 1 to be described later. 1A corresponds to the pattern A in FIG. 14, and FIG. (C) shows the pattern of (a) on the mask and (b)
2 shows an example of an image in the case where the pattern is superposed on a photosensitive substrate, exposed, and developed. This is a so-called moiré mark,
As will be described later, by using this, it is possible to accurately measure the difference between the amounts of image shift of each pattern.

FIG. 15 is a diagram for explaining the principle of moiré. The zigzag pattern extending in the horizontal direction drawn by the solid line in (a) of this drawing is called a main scale here, and the zigzag pattern of a broken line symmetrical with respect to the main scale and the horizontal line is called a sub scale here. I will. These patterns consist of three zigzag patterns in which three line segments having a constant width and inclined at an angle γ or −γ smaller than 45 degrees with respect to the horizontal direction are connected to a series at their ends. Is formed. This figure shows a case of an isolated line pattern because it is a single zigzag pattern.

A resist image obtained by applying the main scale and the vernier scale to different masks, superimposing them on a photosensitive substrate and projecting and exposing the same is shown in (b) or (c). In these figures,
The resist portion shielded from light by the main scale and the vernier scale pattern remains as a resist image as indicated by a diamond-shaped portion R.

FIG. 15B shows a resist image in the case where the main scale and the vernier are ideally superimposed without displacement, and FIG. 15C shows that the main scale image is slightly smaller than the vernier image. Is an image when it is shifted downward. In (b), the horizontal intervals La and Lb of the three formed rhombic images are equal, but (c)
The slight deviation of the main scale shows a large difference between La and Lb. Zigzag tilt angle from horizontal γ or -γ
Is smaller within a range where a rhombus can be formed in relation to the line width, the smaller the distance of the same main scale, the smaller La and Lb
The difference is widened.

In FIG. 15, since the main scale and the sub-scale have the same width, the amount of deviation due to aberration should be the same, and if the positioning at the time of projection is performed accurately, an image as shown in FIG. You should get it. Therefore, the displacement of the resist image as in (c) can be regarded as a positioning error between the main scale and the sub-scale pattern.

Here, assuming that the amount of deviation of the main scale and the vernier from the ideal position as shown in (b) is y as shown in (c), y = ((La−Lb) / 4) The expression of tanγ is satisfied. In this way, if La and Lb are known, y can be obtained.

FIG. 16 is a schematic diagram showing a configuration of an exposure apparatus suitable for performing the aberration measuring method of the present invention. The illumination light beam from the light source LP is shaped into a predetermined light beam by an illumination optical system IL including an optical member (not shown), and is irradiated onto the mask MS.

The illumination optical system IL includes a mercury lamp L
P, elliptical mirror EM, mirror M1, fly-eye lens FL,
The variable aperture stop S1, the lens system L1, the mirror M2, the condenser lens CL, the mask MS, the projection lens OL, and the stage ST on which the wafer WF is mounted are arranged along the optical axis of the projection lens OL in the above order.

The illumination light (i-line or the like) from the lamp LP is formed to have a substantially uniform intensity distribution, and the uniform illumination light is applied to a mask having a fine pattern (instead of a mercury lamp). EX (KrF) laser or the like may be used.

The variable aperture stop S1 is arranged near a Fourier transform plane (hereinafter referred to as a pupil plane of the illumination system) for the mask pattern in the illumination system IL, that is, in the vicinity of the exit plane (mask-side focal plane) of the fly-eye lens FL. Thus, the numerical aperture of the illumination system IL can be changed.

The luminous flux transmitted through the mask MS arranged perpendicular to the optical axis is transmitted through a projection lens OL in two directions X and Y on a plane perpendicular to the optical axis in X and Y directions (not shown). The pattern image on the mask MS is projected and exposed on the resist on the surface of the wafer WF placed on the stage ST movable by a motor for driving. The displacement of the stage ST in the X and Y directions is measured by an interferometer (not shown).

Further, in order to detect an image of a resist formed on the wafer WF, an image processing type observation optical system F (for example, a bright field imaging type) having an optical axis different from the optical axis of the projection lens OL is used. Or an observation optical system LX, LY through which light passes through the projection lens OL (for example, an alignment optical system of a dark-field imaging system).

Arithmetic units (not shown) are provided in advance in the observation optical system F and LX and LY, and the relationship between the amount of positional deviation with respect to the amount of asymmetric aberration of the patterns A and B as shown in FIG. It is memorized. The pattern A and the pattern B are exposed, the relative displacement between the two is determined by the observation optical system F or LX, LY, and the asymmetric aberration of the projection lens is determined from the relative displacement. Inspection like this
The measurement may be performed at a plurality of locations within the projection visual field, and a display or the like (not shown) may be prepared to display a vector map (not shown).

The pattern shape for measurement may be a shape that can be measured not only by the observation optical system F or LX, LY but also by a commercially available overlay measuring device.

FIG. 3 conceptually shows a mask including a reference pattern, which is used in a method of correcting a positional shift of a pattern image.
FIG. 3 shows a case where a moiré mark is used, but the present invention is not limited to this, and for example, a case where a vernier described later is used may be used.

In FIG. 3, reference numeral 100 denotes a mask, and reference numerals 101 and 104 denote two mark groups formed on the mask 100. In one mark group 101, reference pattern 1
02 is arranged on the upper half, and the comparison pattern 103 is arranged on the lower half. In the other mark group 104, a reference pattern 105 is provided on the upper half and a comparison pattern 106 is provided on the lower half.

The mask 100 on which the mark groups 101 and 104 are arranged is arranged in a projection optical system, and the mark groups 101 and 104 overlap with the photosensitive substrate mounted on the stage by the projection optical system. And projection exposure. By developing the exposed substrate, a resist image of an overlapping portion remains on the substrate. The amount of deviation is determined by measuring the resist images of the reference pattern and the comparison pattern.

Here, two mark groups 101 and 104 are used.
Was performed on one mask 100, but may be formed on two separate masks. In that case, the two masks are alternately arranged on the projection optical system whose aberration is to be measured, and the mark groups 101 and 104 are overlapped by the projection optical system on one photosensitive substrate mounted on the stage. And projection exposure. In the following, the resist image is observed in the same manner as when one mask 100 is used, and as described with reference to FIG. 15 or 16, the overlap amount is obtained by subtracting the shift amount of the reference pattern from the shift amount of the comparison pattern. The amount of deviation generated at the time of alignment can be corrected, and an accurate amount of deviation can be obtained.

FIG. 4 shows the mask 100 according to the present invention of FIG.
1 shows a first embodiment of the pattern applied to the first embodiment. In FIG. 4, (a) and (c) are reference patterns, and (b) and (d)
Indicates a comparison pattern.

First, in FIG. 4B, a line width is defined with respect to a first virtual center line LA1 which intersects a horizontally drawn virtual reference line LA0 at an angle α of less than 45 degrees (30 degrees in this figure). The first line and space pattern LS1 formed by the five lines of the WA is the center line of the center line of the line and space pattern LS1, and the virtual center line LA1.
It is formed so as to match. Here, for convenience of display, the lower left portion of the line and space pattern LS1 is not shown. Similarly, the line and space pattern is partially or entirely omitted, and only the virtual center line is shown.

Next, at the point YA on the virtual reference line LA0 separated by a predetermined distance LN1 from the intersection XA of the virtual reference line LA0 and the first virtual center line LA1, the second virtual center intersects at an angle -α. A second line-and-space pattern LS2 formed of a line having a line width WA with respect to the line LA2 is formed such that the center line of the center line of the line-and-space pattern LS2 coincides with the virtual center line LA2. I have.

Here, the distance LN1 is determined such that the intersection of the bottom line of the line and space patterns LS1 and LS2 is above the virtual reference line LA0. Similarly, distances LN2 and LN3, which will be described later, are determined so that the intersection of the lines forming the two line-and-space patterns is on one side of the virtual reference lines LB0, LC0, and LD0.

Similarly, a point ZA on the virtual reference line A separated from the intersection YA by a distance LN1 in a direction opposite to the intersection XA.
With respect to a third virtual center line LA3 intersecting at an angle α at
The third line-and-space pattern LS3 formed by the line having the line width WA is formed such that the center line of the center line of the line-and-space pattern LS3 coincides with the virtual center line LA3. Thus, the first, second and third line and space patterns, LS1,
LS2 and LS3 form a zigzag pattern, and this zigzag pattern is called a first group of line and space patterns. This line and space pattern corresponds to the comparison pattern 103 in the mark group 101 in FIG.

Next, in FIG. 4D, the pattern is similar to the first group of line and space patterns.
4 shows a second group of line and space patterns corresponding to the comparison pattern 106 in the mark group 104 of FIG. 3.

The difference from the first group of line and space patterns is that the line width is WB different from WA. The virtual reference line corresponding to the virtual reference line LA0 is L
B0, the first virtual center line LA1 corresponds to the fourth virtual center line LB1, and the first line and space pattern LS1 formed by the line width WA line corresponds to the line having the line width WB. LS5, LS6 at LS3, and XB at point XA.
, YB for YA, ZB for ZA, LN2 for distance LN1
Corresponds.

The center lines LB1, LB2, LB3 intersect with the reference line LB0 at angles of -α, α, -α, respectively.

It is preferable that LN1 and LN2 are equal, but they may be different.

The line-and-space patterns corresponding to the patterns 103 and 106 in FIG. 1 for comparison of the image shift amount have been described above. Next, the reference patterns will be described.

In the one mark group, a third group of line and space patterns, which are reference line and space patterns, are applied on the mask at positions different from the first group of line and space patterns. It consists of line and space patterns LS7, LS8, LS9. The third group of line and space patterns is formed in the same manner as the first group of line and space patterns. However, the line width is WC, the virtual reference line corresponding to the virtual reference line LA0 is LC0, the first virtual center line LA1 is corresponding to the seventh virtual center line LC1, and the first line and space pattern LS1. What is done is a seventh line-and-space pattern LS7, LS8 also in the line-and-space pattern LS2, LS9 in LS3, XC in point XA, YC in YA, ZC in ZA, and L in distance LN1.
N3 corresponds.

The third group of line and space patterns may have a shape completely identical to the first or second group of line and space patterns.

Next, a fourth group of line and space patterns which are reference patterns in the other mark group will be described.

First, a virtual reference line LD0 is set at a position of a distance LN12 parallel to the virtual reference line LB0. And
Third group line and space pattern and virtual reference line L
A group of line-and-space patterns that are line-symmetric with respect to C0 are applied so that the virtual reference line LC0 coincides with the virtual reference line LD0 to form a fourth group of line-and-space patterns.

Here, in FIG. 4, α and β are drawn as positive angles, but may be negative angles. Also,
The distances LN11 and LN12 are preferably equal, but may be different. If they are different, the shift difference between the pattern images may be corrected by the difference between LN11 and LN12.

In this manner, the mark group 101 is formed by applying the first group of line and space patterns as the pattern 103 in FIG. 3 and the third group of line and space patterns as the pattern 102. The mark group 104 is formed by applying the second group of line and space patterns as the pattern 106 in FIG. 3 and the fourth group of line and space patterns as the pattern 105.

The pattern formed on the mask thus formed is superposed and projected on a photosensitive substrate coated with a resist by a projection optical system whose aberration is to be measured as follows.

First, a mask is manufactured by applying both mark groups so that the distances LN11 and LN12 are equal. These mark groups are provided such that the virtual reference lines LC0 and LD0 are parallel or on the same line.

When the two mark groups are superposed and projected and exposed, ideally, the virtual reference lines LC0 and L0 of the reference pattern
When the exposure is performed so that D0 coincides and points YC and YD coincide, the line width is determined by the difference between the pattern images to be compared and the difference between the pattern images of FIGS. 4B and 4D. Is the difference in the amount of displacement.

The virtual reference lines LC0 and LD0 of the reference pattern
When exposure is performed with a deviation, the moiré marks of those reference patterns are deviated as shown in FIG. 15C, so that the amount of deviation between masks is known, and the pattern to be compared is thereby obtained, as shown in FIG. 4B. By correcting the amount of deviation between (d) and (d), the difference in the amount of deviation due to the difference in line width is obtained.

When the reference pattern is a line and space pattern composed of a plurality of, for example, five dark lines, accurate measurement can be performed by observing the image of, for example, three lines at the center excluding the lines at both ends.

When the distances LN11 and LN12 are different,
The difference may be further corrected by the difference.

The virtual reference lines LA0 and LC0 may be formed as the same straight line, and LB0 and LD0 may be formed as the same straight line. In that case, in FIG.
2 and the comparison pattern 103 are arranged side by side, and the reference pattern 105 and the comparison pattern 106 are arranged side by side. In this way, the distances LN11 and LN12 become 0
Is always equal, which is convenient.

FIGS. 5 to 7 collectively show examples of patterns suitable for the reference pattern or the comparison pattern described with reference to FIG.

FIG. 5 shows combinations of patterns consisting of lines having the same line width. (A) is a case where a main scale line-and-space zigzag pattern 121 having the same line width and a sub-scale line-and-space pattern 122 similar thereto but formed in line symmetry are overlapped. This is the same as (a) and (c) in FIG. 4 described with reference to FIG.

FIG. 5B shows a zigzag pattern 123 of main scale isolated lines having the same line width, and a similar scale but line-symmetrical isolated line 124 of a vernier scale.
This is the case where. This is shown in FIGS. 4A and 4C.
Corresponds to a line obtained by extracting each center line along the virtual center line. 5 (a) and (b) of FIG.
Since the line width is the same, the reference pattern 10 in FIG.
Available as 2, 105.

FIG. 6 shows a combination of patterns composed of lines having different line widths. (A)
Is a line-and-space zigzag pattern 125 having a large line width and a line-and-space pattern 126 having a thin line width and formed in line symmetry with the zigzag pattern 125.
This is the case where. This corresponds to FIGS. 4B and 4D, although the thickness relationship is reversed.

FIG. 6B shows a case in which the line and space pattern 127 and the zigzag pattern 128 of an isolated line formed in line symmetry with the center line are overlapped, although the line width is the same. is there. This corresponds to, for example, a line extracted along the virtual center line from the five lines in FIGS. 4A and 4C.

FIG. 6 (c) shows a zigzag pattern 129 of a main scale isolated line having a large line width, and an isolated line 130 of a small scale having a similar thin line width formed in line symmetry. Is the case. This is equivalent to extracting the center line along the virtual center line in FIGS. 4B and 4D, although the thickness relationship is reversed.

As described above, FIG. 6A, FIG.
Since (c) is a combination of patterns having different line widths or a combination of an isolated line and a line-and-space pattern, the amount of shift of the resist image with respect to the aberration is different, and thus can be used for measuring the aberration. .

FIG. 7 shows a pattern used in the vernier method according to the second embodiment of the present invention. First, main scale 1
51 is formed from five thin lines, and
It is formed from the thick lines of the book. In this example, four thick lines of the vernier scale are equally divided into five to form a main scale of a thin line. For simplicity, the line widths of the main scale and the vernier scale are greatly different from each other. In practice, the line widths of the main scale and the vernier scale are slightly different. For example, the main scale is a 0.7 μm line and space pattern, and the vernier scale is a 0.72 μm line and space pattern. The smaller the difference, the finer the reading, but the higher the accuracy.

A vernier 153 of the resist image formed by superposing the above-described main scale and sub-scale patterns so that the respective lines overlap in parallel is 153. Knowing the position of the vernier thickest resist line in the vernier, the deviation between the main scale and the vernier scale pattern image can be determined as in the case of the normal vernier method. FIG. 7 shows a case where there is no shift, and the thick line is at the center.

Since the width of the resist image of the lines at both ends of the line and space pattern changes, a line at the center, for example, a line and space pattern composed of 50 lines is prepared, and the center of the resist image near the center is prepared. By observing 30 to 40 lines, the deviation between the lines having no change in the line width (thickness) can be understood.

The main scale and the vernier scale described above can be used as a reference pattern. Because, for example, the difference between the positional deviation of the resist image between the line-and-space pattern having a line width of 0.7 μm and the line-and-space pattern having a line width of 0.72 μm is almost zero as can be seen from FIG. Therefore, the positional deviation that can be known by the vernier is a deviation between the set positions of the main scale pattern and the sub scale pattern, which can be used for correction.

Next, by using a phase shifter for one of the main scale and the sub-scale having substantially the same line width, the same effect as that of overlapping patterns having a line width difference can be obtained. In other words, when a phase shifter is used for a vernier with a line width of 0.72 μm, the aerial image is similar to a line and space pattern with a line width of 0.7 μm and a line of space of 0.31 μm superimposed, and a large displacement occurs. On the other hand, the resist image becomes an original image of the main scale and the vernier scale having slightly different line widths, so that the positional deviation of the resist image can be known by the vernier method.

On the other hand, the main scale and sub scale patterns 151 and 152 using a phase shifter on one side are combined with the pattern 10 in FIG.
3, 106, the reference patterns 102, 105
Alternatively, a pattern as shown in FIGS. 5A and 5B may be set and used so that its virtual reference line is parallel to the main scale and the vernier scale.

FIGS. 8 to 12 show examples of comparison patterns that do not require a reference pattern.

FIG. 8 shows a line and space pattern formed on one mask according to a third embodiment of the present invention. First, a line and space pattern block consisting of five dark lines having a predetermined length and a thickness of 0.70 μm is arranged in a line lengthwise direction to form a first set of line and space patterns. A second set of line and space patterns, which is a set of blocks of the same line and space pattern, is applied at appropriate intervals in the line pitch direction, and then the first and second sets of line and space patterns are formed. Within the interval, a block of a line and space pattern consisting of five dark lines having the same length as the predetermined length and a thickness of 0.35 μm is equidistant from the first and second sets of line and space patterns. Four lines are arranged in the vertical direction to form a third set of line and space patterns. Such a line and space pattern is herein referred to as LSA (LASER Step Al).
(mark) mark. This is an alignment optical system of a dark field imaging type, and one of alignment sensors incorporated in a stepper (reduction projection exposure apparatus).
One. The LSA (AMS) mark is usually 4
The pattern is a μm square pattern.

Using such a combination of the LSA marks, the first and third sets of the resist images are used.
By measuring the intervals between the second set and the third set, it is possible to know the difference between the relative movement amounts of the images of the 0.70 μm and 0.35 μm line and space patterns.
In this case, only the combination of the first set and the third set, or only the combination of the second set and the third set, can measure the interval to know the difference in the relative movement amount, or can measure both. By averaging the values, more accurate values can be obtained. The measurement of the position of the LSA mark can be performed as described below with reference to FIGS.

FIG. 10 shows the relationship between the LSA mark and the irradiation light. In this embodiment, five blocks of a line and space pattern consisting of five dark lines having a pitch of P = 8 μm, a mark length of 4 μm in the same direction, and a line width of 0.7 μm in the direction of arrangement of LSA mark blocks are arranged. .

Similarly, five blocks of a line and space pattern having a line width of 0.35 μm are provided in parallel with the 0.75 μm line and space pattern, separated by 20 μm in the line pitch direction. Here, FIG. 10A is a side view of the mark, and FIG. 10B is a plan view.

The wavelength λ (for example, 632.
8 nm), diffracted light is generated. It is known that the diffraction angle θ in the direction in which the diffracted light is generated satisfies the equation of Psin θ = nλ, where n is the order. Further, the direction in which the diffracted light is generated is the direction of the block pitch P in FIG. In the figure, +1 in the direction of the diffraction angle θ
A secondary light 201 and a primary light 202 are generated. The diffracted light is received as described below with reference to FIG. 11, and the position can be obtained from the interferometer of the stepper stage.

That is, a peak appears in the light intensity due to the diffraction efficiency of the diffracted light between adjacent blocks. The peak due to the middle lines in the block is high. Measuring the distance between the peaks shows how much the original distance of 20 μm has shifted.

In FIG. 11, a projection lens system 302 disposed below a reticle 301 and a stage 303 on which a wafer 304 is placed at an image forming position constitute a part of a projection exposure apparatus. The resist on the wafer 304
An image 305 of the LSA mark applied to the reticle 301 is formed. A laser 30 is located above the projection lens system.
6 is provided to irradiate the laser beam toward the projection lens system. The laser beam passes through the beam splitter 307, enters the mirror 308, enters the projection lens system 302, is refracted here, and irradiates the LSA mark 305 almost perpendicularly. As described with reference to FIG. 10, diffracted light is generated at the LSA mark. The diffracted light again passes through the projection lens system 302, passes through the mirror 308, and reaches the beam splitter 308. The diffracted light reflected here is incident on the diffracted light receiving section 309 arranged in the optical path and detected. Here, the photoelectrically converted signal is output to the arithmetic unit 31.
0, and the interfering system synchronization signal received by the stage interferometer light receiving unit 311 is also sent to the arithmetic unit 310,
The two signals are arithmetically processed together, and the position of the image of the LSA mark is accurately measured based on the processing result.

The blocks constituting the LSA mark are shown in FIG.
0 indicates a case of five, but may be two or more. However, seven or more are preferable. This is because the diffraction efficiency increases. When the LSA mark is used, the distance (2 in FIG. 10) between blocks made of line and space patterns having different thicknesses (0.7 μm and 0.35 μm in FIG. 10).
0 μm), it is not necessary to prepare a pattern having the same line width as a reference.

When a pattern as shown in FIG. 8 is used, the measurement can be performed with an alignment sensor or a measuring device other than those described in detail above, for example, an FIA or an overlay measuring device.

FIG. 9 shows a variation of the pattern of FIG. This is a continuous line and space pattern in which the lines of each block in FIG. 8 are extended. This pattern is particularly suitable for measurement by FIA. This is because diffraction efficiency is unnecessary when performing image processing.

FIG. 12 shows an example of a box pattern according to the fourth embodiment of the present invention. (A) shows a square outer frame having five thick dark line-and-space patterns arranged on each side, and five thin dark line-and-space patterns arranged concentrically and similarly. The inner frame is a so-called box pattern in which each side is arranged in parallel. Because there is a difference in the thickness of the line,
The moving amounts of the resist images of the outer frame and the inner frame are different, and the frames are eccentric. The amount of eccentricity may be measured. (B)
Each side is parallel to a square outer frame having one thick dark line isolated line pattern on each side and a square inner frame consisting of one thin dark line isolated line pattern arranged concentrically. This is also a box pattern. Since there is a difference in the line thickness, the amount of movement of the resist image between the outer frame and the inner frame is different, and the frames are eccentric. The amount of eccentricity may be measured. Also, a thick line pattern may be used as the inner frame.

In this case as well, the outer frame and the inner frame may be formed exactly concentrically, or the positional relationship between them may be accurately grasped, and it is necessary to expose different patterns formed on the mask in a superimposed manner. Since there is no reference pattern, the reference pattern is unnecessary. If the outer frame and the inner frame cannot be formed exactly concentrically, the amount of eccentricity may be grasped, and the measured amount of deviation may be corrected accordingly.

As described above, the positive pattern has been described in the drawings, but the same applies to the case of a negative pattern.

The measurement pattern is not limited to the pattern shown in the figure, but may be any line and space pattern extending in a predetermined direction. Further, the number of lines may be one or more, but especially in the case of three or more lines, it is desirable to measure the remaining line positions excluding the lines at both ends in the pitch direction of the pattern. This is to eliminate the influence of the wraparound of the illumination light beam.

In the above description, in the case of the line and space pattern, the center line 1 is used instead of the lines at both ends.
Although it has been described that it is preferable to measure the deviation amount for only one or a plurality of lines, it is easier to perform the actual measurement by removing the images of the lines at both ends from the resist image. FIG. 2 illustrates the method. However, in this case, it is assumed that the line and space pattern is a positive pattern.

FIG. 2A shows a light-shielding pattern covering three central lines of the line-and-space pattern composed of five dark lines in FIG. 1A, and FIG. (B) The center 3 of the line and space pattern
The light-shielding pattern covering the book line is shown.

As shown in FIG. 1 (c), after the overlay exposure, the light-shielding patterns (a) and (b) of FIG. 2 are overlaid and exposed, respectively, as shown in FIG. 2 (c). The lines at both ends of each line and space pattern are exposed and disappear, leaving only the image of the three central lines. In this way, it is possible to accurately measure the line displacement.

The measurement object of the present invention may be not only a projection refraction optical system but also a catadioptric optical system. Further, it is not necessary to share the configuration in the exposure apparatus with the measurement apparatus, and a dedicated measurement apparatus may be used.

[0112]

As described above, according to the present invention, the amount of positional deviation of an image on a resist of a pattern is measured when the amount of asymmetry of an image of a projection optical system or the like is measured. It is not necessary to use a complicated microscope such as a microscope, so that the trouble of setting the apparatus can be eliminated, and the aberration amount of the projection optical system and the like can be measured at high speed and with high accuracy. Further, since the difference between the positional deviation amounts of the images of different patterns is measured, there is no need to know the absolute position of the image, and there is no need to use a complicated microscope. In addition, since the overlay error can be corrected using the image of the comparison pattern, it is not necessary to pay much attention to the pattern alignment, and the aberration amount of the projection optical system or the like can be measured at high speed and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a zigzag pattern and a moiré mark used in an embodiment of the present invention.

FIG. 2 is a diagram of a light-shielding pattern used for clearly measuring a moiré mark used in an embodiment of the present invention.

FIG. 3 is a conceptual diagram of a mask provided with a comparison pattern and a reference pattern used in an example of the present invention.

FIG. 4 is a diagram illustrating in detail a zigzag pattern according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an example of a reference pattern used in the embodiment of the present invention.

FIG. 6 is a diagram illustrating an example of a comparison pattern used in an example of the present invention.

FIG. 7 is a diagram illustrating an example of a comparison pattern used in the vernier method according to the second embodiment of the present invention.

FIG. 8 is a diagram showing a pattern when using an LSA mark according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a modified pattern of the pattern shown in FIG. 8;

FIG. 10 is a diagram showing a relationship between an LSA mark and irradiation light.

FIG. 11 is a schematic diagram illustrating a measurement device used for measurement using an LSA mark.

FIG. 12 is a diagram showing a box pattern used in a fourth embodiment of the present invention.

FIG. 13 is a diagram illustrating an intensity distribution and an aerial image intensity distribution of a pattern on a mask.

FIG. 14 is a graph showing a relationship between an image forming position shift amount, a pattern line width, and an asymmetric aberration amount.

FIG. 15 is a diagram illustrating the principle of moiré.

FIG. 16 is a schematic view of an apparatus suitable for measurement according to the present invention.

[Explanation of symbols]

 100 Mask 101, 104 Mark group 102, 105 Reference pattern 103, 106 Comparison pattern LA0, LB0, LC0, LD0 Virtual reference line LA1, LB1, LC1, LD1 Virtual center line LA2, LB2, LC2, LD2 Virtual center line LA3, LB3 , LC3, LD3 Virtual center line LS1-LS9 Line and space pattern

Claims (14)

[Claims] An aberration measuring method for measuring an aberration amount of a projection optical system, wherein a mask provided with a pattern including one of a line-and-space pattern and an isolated line pattern is arranged in an optical path of the projection optical system. A step of disposing a resist-coated substrate at a projection position of the projection optical system; a step of projecting the pattern onto the resist of the substrate by the projection optical system to expose the resist; And a step of measuring a shift amount of a position of a line-and-space pattern image or an isolated line pattern image by a resist formed on the substrate by the developing step. 2. An aberration measuring method for measuring an aberration amount of a projection optical system, comprising: a first pattern including a line-and-space pattern having a predetermined line width A and an isolated line pattern;
Disposing a mask provided with a line-and-space pattern having a predetermined line width WB different from the second line pattern including any one of the isolated line patterns in the optical path of the projection optical system; Disposing the exposed substrate at a projection position of the projection optical system, projecting each pattern on the mask onto a resist of the substrate by the projection optical system and exposing the same, and developing the exposed substrate. And a step of measuring an amount of displacement between a line of the image of the first pattern and a line of the image of the second pattern due to the resist formed on the substrate by the developing step. , Aberration measurement method. 3. The aberration measurement method according to claim 2, wherein each line of the first and second patterns is applied to the mask so as to be parallel to each other. 4. An aberration measuring method for measuring an aberration amount of a projection optical system, comprising: a first pattern including one of a line-and-space pattern having a predetermined line width WA and an isolated line pattern;
A second pattern including any one of a line-and-space pattern and an isolated line pattern having a predetermined line width WB different from A, and a second pattern including any one of the line-and-space pattern and the isolated line pattern having the predetermined line width WB. Disposing a mask provided with the pattern 3 in the optical path of the projection optical system; disposing a substrate coated with a resist at a projection position of the projection optical system; Projecting and exposing the resist on the substrate by the projection optical system, developing the exposed substrate, and forming an image of the first pattern by the resist formed on the substrate by the developing step The amount of displacement between the line of the second pattern and the line of the image of the second or third pattern is corrected based on the positions of the line of the image of the second pattern and the line of the image of the third pattern. And a step of measuring. 5. The aberration measuring method according to claim 4, wherein each line of the first, second, and third patterns is applied to the mask so as to be parallel to each other. 6. An aberration measuring method for measuring an aberration amount of a projection optical system, comprising: a first pattern including one of a line-and-space pattern having a predetermined line width WA and an isolated line pattern; Disposing a first mask having a WB line-and-space pattern and a second pattern including any of the isolated line patterns in an optical path of the projection optical system; A second mask including a third pattern including one of a space pattern and an isolated line pattern and a fourth pattern including one of a line-and-space pattern having the predetermined line width WB and an isolated line pattern is provided. Disposing in a light path of the projection optical system; disposing a substrate coated with a resist at a projection position of the projection optical system; Projecting a pattern on a mask onto a resist of the substrate by the projection optical system, and exposing the resist; developing the exposed substrate; and developing the resist on the substrate by the developing process. The amount of positional deviation between the line of the first pattern image and the line of the third pattern image is determined by the position of the line of the second pattern image and the position of the line of the fourth pattern image. Correcting based on, and measuring. 7. The mask is applied such that each line of the first and second patterns is parallel to each other, and each line of the third and fourth patterns is parallel to each other. 7. The aberration measuring method according to claim 6, wherein the step of exposing includes a step of arranging each mask such that each line of each pattern of each mask is parallel to each other. 8. An aberration measuring method for measuring an aberration amount of a projection optical system, wherein each line is parallel to a first virtual center line that intersects an arbitrary virtual reference line LA0 at an angle α of less than 45 degrees. And a first line formed of a line having a predetermined line width WA arranged symmetrically with the line.
And the virtual reference line L
A predetermined distance L from the intersection XA between A0 and the first virtual center line
Angle -α at point YA on virtual reference line LA0 separated by N1
A second line-and-space pattern formed by lines of the predetermined line width WA, wherein each line is arranged in parallel and line-symmetrically with respect to a second virtual center line intersecting with the second virtual center line; Each line is parallel and line-symmetric with respect to a third virtual center line intersecting at an angle α at a point ZA on a virtual reference line LA0 separated by a predetermined distance LN1. A first group of line and space patterns including a third line and space pattern formed by lines, wherein the first, second, and third line and space patterns form a zigzag pattern. Arranging one of the masks in the optical path of the projection exposure system; and each line being parallel and line symmetric with respect to a fourth virtual center line that intersects an arbitrary virtual reference line LB0 at an angle -α of less than 45 degrees. Arranged in A fourth line-and-space pattern formed by a line having a predetermined line width WB and a virtual reference line LB0 separated by a predetermined distance LN2 from an intersection XB between the virtual reference line LB0 and the fourth virtual center line. Angle α at point YB
A fifth line-and-space pattern formed by the line having the predetermined line width WB, wherein each line is arranged in parallel and line-symmetrically with respect to a fifth virtual center line intersecting with the fifth virtual center line; The predetermined line width WB, wherein the respective lines are arranged in parallel and line-symmetrically with a sixth virtual center line intersecting at an angle -α at a point ZB on a virtual reference line LB0 separated by a predetermined distance LN2. And a sixth line-and-space pattern formed by the fourth, fifth and sixth lines.
A line and space pattern forming a zigzag pattern, a step of arranging the other mask on which the second group of line and space patterns are applied in the optical path of the projection exposure system, and Disposing at a projection position of the projection optical system, and a first group of line and space patterns on the one mask and a second group of line and space patterns on the other mask, A step of projecting and exposing the resist on the resist, a step of developing the projected substrate, and a first group of line and space images and a second group of resist formed on the substrate by the developing step. Measuring the positional deviation between the lines of the line-and-space image using a moiré mark. 9. A virtual reference line LC0 parallel to the virtual reference line LA0 and at a predetermined distance LN11 at a position different from the line and space pattern of the first group.
A seventh line-and-space pattern formed by a line having a predetermined line width WC, wherein each line is arranged in parallel and line-symmetrically with respect to a seventh virtual center line intersecting at an arbitrary angle β A virtual reference line LC0 separated by a predetermined distance LN3 from an intersection XC between the virtual reference line LC0 and the seventh virtual center line
An eighth line formed by the line having the predetermined line width WC, wherein the respective lines are arranged in parallel and line-symmetrically with respect to an eighth virtual center line intersecting at an angle −β at the upper point YC. The space pattern and the predetermined distance L from the intersection YC
Each line is formed in parallel with the ninth virtual center line intersecting at an angle β at a point ZC on a virtual reference line LC0 separated by N3 with a line having the predetermined line width WC. A ninth line and space pattern,
Arranging one of the masks on which the seventh, eighth, and ninth line-and-space patterns form a zigzag pattern and on which a third group of line-and-space patterns has been applied, in the optical path of a projection exposure system; Further, at a position different from the line and space pattern of the second group, the line and space pattern of the third group and a line and space pattern of a fourth group symmetrical with respect to the virtual reference line LC0 are provided. , The virtual reference line LB
A virtual reference line L parallel to 0 and at a predetermined distance LN12
Arranging the other mask in the optical path of the projection exposure system, the other mask being applied so that the virtual reference line LC0 substantially coincides with D0; Measuring the positional shift between the lines of the line-and-space image using the moiré mark, the moire mark between the image of the third group of line-and-space patterns and the image of the fourth group of line-and-space patterns The aberration measuring method according to claim 8, further comprising a step of performing measurement by correcting the aberration. 10. The aberration measuring method according to claim 9, wherein the distance LN11 and the distance LN12 are set to be equal. 11. A line having a predetermined line width WA in which each line is arranged in parallel and line-symmetrically with a first virtual center line crossing an arbitrary virtual reference line LA0 at an angle α of less than 45 degrees. A first line and space pattern to be formed;
Intersection XA between the virtual reference line LA0 and the first virtual center line
The predetermined line width, wherein each line is arranged in parallel and line-symmetrically with a second virtual center line which intersects at a point YA on the virtual reference line LA0 at a predetermined distance LN1 at an angle -α. A second line-and-space pattern formed by lines of WA and a third virtual center line that intersects at an angle α at a point ZA on a virtual reference line LA0 separated by the predetermined distance LN1 from the intersection YA. A third line-and-space pattern formed by the lines having the predetermined line width WA, wherein the lines are arranged in parallel and line-symmetrically, and the first, second, and third line-and-space patterns are provided. A projection optical system mask provided with a first group of line-and-space patterns, wherein the patterns form a zigzag pattern. 12. The projection optical system mask according to claim 11, wherein each line is parallel to a fourth virtual center line intersecting an arbitrary virtual reference line LB0 at an angle -α of less than 45 degrees. A fourth line-and-space pattern formed by symmetrically arranged lines having a predetermined line width WB and a predetermined distance LN2 from an intersection XB between the virtual reference line LB0 and the fourth virtual center line. Angle α at point YB on virtual reference line LB0
A fifth line-and-space pattern formed by the line having the predetermined line width WB, wherein each line is arranged in parallel and line-symmetrically with respect to a fifth virtual center line intersecting with the fifth virtual center line; The predetermined line width WB, wherein the respective lines are arranged in parallel and line-symmetrically with a sixth virtual center line intersecting at an angle -α at a point ZB on a virtual reference line LB0 separated by a predetermined distance LN2. And a sixth line-and-space pattern formed by the fourth, fifth and sixth lines.
A second group of line-and-space patterns, wherein the line-and-space patterns form a zigzag pattern. 13. The virtual reference line LA0 at a position different from the first group of line and space patterns.
Virtual reference line LC parallel to and at a predetermined distance LN11
A predetermined line width WC in which each line is arranged parallel and line-symmetric with respect to a seventh virtual center line that intersects 0 at an arbitrary angle β.
And a virtual reference line LC separated by a predetermined distance LN3 from an intersection XC between the virtual reference line LC0 and the seventh virtual center line.
An eighth line formed by the line having the predetermined line width WC, wherein the lines are arranged in parallel and line-symmetrically with an eighth virtual center line intersecting at an angle −β at a point YC on 0. An angle β between an AND space pattern and a point ZC on a virtual reference line LC0 separated by the predetermined distance LN3 from the intersection YC.
A ninth line-and-space pattern formed of lines having the predetermined line width WC, wherein each line is arranged in parallel and line-symmetrically with respect to a ninth virtual center line intersecting The projection optical system mask according to claim 11, wherein a third group of line and space patterns, in which the third and eighth and ninth line and space patterns form a zigzag pattern, are applied. 14. The projection optical system mask according to claim 13, further comprising: a third group of line and space patterns and the virtual reference line at a position different from the second group of line and space patterns. A fourth group of line-and-space patterns line-symmetric with respect to LC0 is the virtual reference line LB.
A virtual reference line L parallel to 0 and at a predetermined distance LN12
A set of projection optical system masks, comprising: the other mask applied so that the virtual reference line LC0 substantially matches D0.