JP2003344987A - Eaves quantity measuring method for phase shift mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly grasp the eaves quantity of a phase shift mask without making a sectional observation of the phase shift mask and to guarantee the quality of the phase shift mask more securely. <P>SOLUTION: The method of measuring the eaves quantity of a circuit pattern 10 of an eaves type Levenson PSM 100 includes a stage of forming the circuit pattern 10 and a monitor pattern 20 of specified size on quartz-made blanks 1, a stage of forming step part 33A and 33B on the blanks 1 where the monitor pattern 20 and circuit pattern 10 are formed by performing anisotropic dry etching and isotropic wet etching, and a stage of removing the monitor pattern 20 from the blanks 1 where the step parts 33A and 33B are formed and measuring the size of a specified area 25 demarcated with the step part 33B right below the monitor pattern 20 as the eaves quantity. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a step portion for shifting the phase of light emitted from an exposure apparatus by 180 °, and an eaves portion covering a part of the step portion, thereby providing super resolution. The present invention relates to a method for measuring an eaves amount of a phase shift mask suitable for application to an eaves-type Levenson phase shift mask to be achieved. Specifically, after forming a light-shielding pattern and a monitor pattern of a predetermined size on a substrate, a predetermined etching process is applied to this substrate to form a step portion, and the monitor pattern is formed from the substrate on which the step portion is formed. By measuring the dimension of the substrate surface of the specific area remaining after removal as the eaves amount, the eaves amount of this phase shift mask can be correctly grasped without observing the cross section of the phase shift mask. .

[0002]

2. Description of the Related Art In recent years, semiconductor integrated circuits are becoming finer and finer. Along with this, in a lithography process of a semiconductor integrated circuit, a phase shift mask is used in order to extend the life of an optical lithography technique for fine processing. The phase shift mask is an exposure mask (reticle) for improving the resolution by selectively modulating the phase of light passing through the mask.

Among the phase shift masks, the Levenson phase shift mask, which partially forms a stepped portion (recess) on the quartz substrate to modulate the phase, has a large effect of miniaturization.
It is being studied as a candidate for next-generation lithography technology.
In addition, in the step portion of this Levenson phase shift mask, Cr
It is possible to prevent light scattering (waveguide effect) on the side wall of the stepped portion by providing an eaves portion formed of a light shielding film such as, and it is effective in reducing the pattern shift after the transfer to the wafer. Are known.

This Levenson phase shift mask (hereinafter Levenson PSM: Phase Shift Mas)
(also referred to as “k”), and the purpose and effect of the eaves-type PSM are as described in detail in Japanese Patent No. 3127148 or Japanese Patent Laid-Open No. 6-180497.
Among these, in the production of the eaves-type Levenson PSM, controlling the eaves amount of the light-shielding film (the dimensional length of the eaves portion) to a desired value is particularly important for ensuring the quality.

In order to obtain the eaves amount of this eaves type PSM truly correctly, the PSM is cut and its cross section is S.
EM (Scanning Electron Micro)
The only method is direct measurement with an oscopy: scanning electron microscope. However, this method impairs the value of PSM as a product and is not practical.

Therefore, an indirect measuring method as shown in FIGS. 9A and 9B has been adopted. 9A and 9B are process diagrams showing a method of measuring an eaves amount of an eaves-type Levenson PSM 90 according to a conventional example.

As shown in FIG. 9A, an anisotropic dry etching process is performed on a quartz blank 91 having a light-shielding pattern 95 made of a light-shielding film to form a step portion (recess) 92 for phase shift. To do. Step portion 92 at this time
Let a be the depth of. The depth a of the step portion 92 is measured by an AFM (Atomic F) which is a known step measuring device.
ore Microscope: atomic force microscope) or the like is used.

Next, hydrofluoric acid treatment is applied to the blanks 91 to expand the step portions 92 in the downward and lateral directions as shown in FIG. 9B. Then, after the hydrofluoric acid treatment, the step portion 92
Depth is measured again by AFM. Step portion 92 at this time
Be the depth of b.

If the downward etching amount (digging amount) of the step portion 92 by this hydrofluoric acid treatment is c, then c is expressed by an equation. c = ba ...

Further, the lateral etching amount (side etching amount) of the step portion 92 by this hydrofluoric acid treatment is c ′.
Then, since the hydrofluoric acid treatment is isotropic wet etching, c ′ is represented by the formula. c′≈c = b−a ... '

As shown in FIG. 9B, c'represented by this'equation is the eaves amount of the eaves portion 95A. This'formula assumes that the downward etching amount c of the blanks 91 and the lateral side etching amount c'are the same.

[0012]

By the way, according to the measuring method of the eaves amount of the eaves type Levenson PSM90 according to the conventional method, the depths a and b of the stepped portion before and after the hydrofluoric acid treatment are carried out.
Respectively, and the measured values of a and b are approximated by
To obtain the eaves amount c ′. That is, it was premised that the amount of etching downward of the substrate by the hydrofluoric acid treatment was the same as the amount of side etching laterally.

Therefore, the eaves amount c obtained from '
However, there is a problem that the amount of eaves cannot be correctly grasped because there is an error between the actual amount of eaves and the amount of eaves. For example, even if the eaves amount c obtained from the equation is the eaves amount within the cleaning resistance limit (within the standard), it actually exceeds this limit, and the eaves-type Levenson PSM (hereinafter, also referred to as a phase shift mask) There was a problem that the eaves would break during cleaning. Further, even if the eaves amount c obtained from the formula is within the standard, the actual eaves amount does not satisfy the standard, and there is a possibility that the transferability may be adversely affected.

Therefore, the present invention solves such a problem, and makes it possible to correctly grasp the eaves amount of the phase shift mask without observing the cross section of the phase shift mask, It is an object of the present invention to provide a method for measuring an eaves amount of a phase shift mask which can more surely assure the quality of the shift mask.

[0015]

The above-mentioned problem is a method of measuring the eaves amount of a phase shift mask, which comprises a step of forming a light-shielding pattern and a monitor pattern of a predetermined size on a substrate, and this monitor pattern. A step of forming a step portion on the substrate by performing a predetermined etching process on the substrate on which the light shielding pattern is formed, and removing the monitor pattern from the substrate on which the step portion is formed, And a step of measuring a dimension of a substrate surface of a specific region defined by the step portion as an eaves amount, which is solved by a method for measuring an eaves amount of a phase shift mask.

According to the method for measuring the eaves amount of the phase shift mask according to the present invention, the eaves amount of the phase shift mask can be correctly grasped without observing the cross section of the phase shift mask.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for measuring an eaves amount of a phase shift mask according to the present invention will be described in detail with reference to the drawings. (1) Embodiment FIGS. 1 to 5 are process diagrams showing a canopy amount measuring method (parts 1 to 5) of an eaves-type Levenson PSM 100 according to an embodiment of the present invention. In this embodiment, a light shielding pattern,
After forming a monitor pattern with a predetermined size on the substrate,
This substrate is subjected to a predetermined etching process to form a step portion, the monitor pattern is removed from the substrate on which the step portion is formed, and then the substrate surface of a specific region defined by the step portion directly below the monitor pattern. By measuring the dimension as the eaves amount, the eaves amount of the phase shift mask can be correctly grasped without observing the cross section of the phase shift mask.

As shown in FIG. 1A, first, a transfer area and a non-transfer area are defined on a blank 1 (an example of a substrate) made of quartz. Here, the transfer area is a blank 1 (that is, PSM100) on which a light shielding film having a predetermined shape is formed.
Means a region irradiated with light emitted from a light source of the exposure device toward a semiconductor wafer (not shown) when the is set on an exposure device (not shown) such as a stepper. Further, the non-transfer area means an area to which the light emitted from the light source of the exposure device toward the semiconductor wafer does not reach.

Next, as shown in FIG. 1A, a linear circuit pattern (an example of a light-shielding pattern) 10 made of a light-shielding film such as Cr is formed on the blanks 1 in the transfer area. At the same time as the formation of the light-shielding pattern 10 or before or after the formation of the light-shielding pattern 10, a rectangular monitor pattern 20 made of a light-shielding film such as Cr is also formed on the blanks 1 in the non-transfer area.

Here, the circuit pattern 10 shown in FIG. 1A.
Is a light-shielding film for transferring a circuit pattern onto a resist film (not shown) applied on the semiconductor wafer. The circuit pattern 10 is about four times as large as the resist pattern (not shown) formed on the semiconductor wafer. As shown in FIG. 1B, this circuit pattern 10
When the line width of L1 is L1, L1 is, for example, about 400 nm. The monitor pattern 20 shown in FIG. 1B is a monitor film for measuring the eaves amount of the eaves portion, which will be described later. These circuit pattern 10 and monitor pattern 2
The formation of 0 is performed by, for example, EB (electron beam) drawing, development, and light-shielding film etching.

As shown in FIG. 1A, after the monitor pattern 20 is formed on the blank 1, the monitor pattern 2 is formed.
The horizontal length (line width) of 0 and the vertical length are measured. The dimension of the monitor pattern 20 is measured by, for example, the monitor pattern 2 by SEM (an example of a measuring device).
The upper surface of 0 is observed.

In FIG. 1A, this monitor pattern 20
When the line width of A is Ax, Ax is, for example, 300 nm. In addition, the vertical length of the monitor pattern 20 is A
When y is set, Ay is, for example, 300 nm.

Next, as shown in FIG. 2A, a resist pattern 31 is formed on the monitor pattern and the circuit pattern formed in the non-transfer area, and on the circuit pattern formed in the transfer area and a part of the blanks 1. Form. The resist pattern 31 is formed by EB lithography.

Then, using the resist pattern 31 as a mask, the blank 1 is subjected to anisotropic dry etching. As a result, as shown in FIG. 2B, the step portion 33A is formed in the blanks 1 in the transfer area, and the step portion 33B is formed in the blanks 1 in the non-transfer area. The dry etching process, for example RIE using CF ₄ (R
by active Ion Etching).

Next, in FIG. 2B, until the depth of the step portions 33A and 33B reaches a desired depth (digging amount),
Hydrofluoric acid treatment is applied to the blank 1. This step 33
The desired depths of A and 33B are 171 nm when using, for example, an ArF excimer laser (wavelength 193 nm) as the light source of the stepper. Blanks 1 of PSM100
By selectively providing a step portion of 171 nm in
The phase of laser light with a wavelength of 193 nm that passes through this step is set to 1
It can be shifted by 80 degrees and super resolution can be obtained.

The hydrofluoric acid treatment is isotropic wet etching. Therefore, as shown by the arrow in FIG. 3A, the blanks 1 are side-etched in the direction of the broken line from the edge of the resist pattern 31 by this hydrofluoric acid treatment.

As a result, as shown in FIG. 3B, the step portion 3
3A and 33B are adapted to spread in the downward and lateral directions of the blank 1. Since the transfer area and the non-transfer area are on the same blank 1, the side etching amount by the hydrofluoric acid treatment is the same in the step portions 33A and 33B.

Then, the blanks 1 selectively covered with the resist pattern 31 are subjected to a known ashing process. As a result, the resist pattern is removed from the blank 1 as shown in FIG. 4A.

As shown in FIG. 4B, the upper portion of the side wall portion of the step portion 33A is covered with the end portion of the circuit pattern 10. The upper side wall of the step portion 33B is covered by the end of the monitor pattern 20. Hereinafter, one portion of the circuit pattern 10 that covers the upper side wall of the step portion 33A is also referred to as an eaves portion 10A. Further, one portion of the monitor pattern 20 that covers the upper side wall of the step portion 33B is also referred to as an eaves portion 20A. Eaves 1 of this circuit pattern 10
0A and the eaves portion 20A of the monitor pattern 20 are formed by the lateral etching of the hydrofluoric acid treatment described above.

Next, this monitor pattern 20 is set to FIB.
(Focused Ion Beam: Focused ion beam) or laser is used to peel and remove. This completes the PSM 100 as shown in FIG. 5A. Further, as shown in FIG. 5A, by removing this monitor pattern, a specific area 25 defined by the step portion 33B and the circuit pattern 10 of the non-transfer area appears.

Next, the horizontal length and the vertical length of the specific area 25 are measured. This specific area 2
The dimension measurement of 5 is performed by observing the upper surface using an SEM, as in the dimension measurement of the monitor pattern 20, for example. When the horizontal length of the specific region 25 is Bx, Bx is, for example, 200 nm. When the vertical length of the specific region 25 is By, By is, for example, 100 nm.
Is.

By the way, when the dimensions Bx and By of the specific region 25 of the blank 1 measured in FIG. 5A are subtracted from the dimensions Ax and Ay of the monitor pattern 20 measured in FIG. 1A,
The eaves amount of the eaves portion 20A of the monitor pattern can be calculated.

That is, in FIG. 5B, when the lateral canopy amount of the canopy portion 20A is Cx, Cx is expressed by an equation. Cx = Ax−Bx ... Further, when the eaves amount of the eaves portion 20A in the vertical direction is Cy (not shown), Cy is represented by an equation. Cy = (Ay-By) / 2 ...

As shown in FIG. 1A, the monitor pattern 2
Since one side in the horizontal direction of 0 is adjacent to the circuit pattern 10, side etching of the step portion may be considered only on one side. On the other hand, since the monitor pattern 20 is not adjacent to the circuit pattern 10 or the like in the vertical direction, side etching of the step portion is performed from both sides. Therefore, the denominator is 2 in the formula.

The eaves portion of the monitor pattern 20 is formed by the hydrofluoric acid treatment which is the isotropic etching treatment shown in FIG. 4B. Therefore, the canopy amounts Cx and Cy are equal to the canopy amount of the circuit pattern 10 formed on the same blank 1 as the monitor pattern 20.

Therefore, in FIG. 5B, when the lateral canopy amount of the circuit pattern 10 is Cx ', Cx' is expressed by an equation. Cx ′ = Cx ... Further, when the length of the circuit pattern in the vertical direction is Cy ′ (not shown), Cy ′ is expressed by an equation. Cy '= Cy ...

In the formulas and formulas, for example, Ax = 30
Since 0 nm and Bx = 200 nm, Cx ′ = 100 nm
Is. Furthermore, in the formulas and formulas, for example, Ay =
Since 300 nm and By = 100 nm, Cy ′ = 100
nm.

As described above, according to the canopy amount measuring method for the canopy-type Levenson PSM100 according to the embodiment of the present invention, when measuring the canopy amount of the circuit pattern 10 in the PSM100, the circuit pattern 10 and the monitor pattern 20 can be measured. Are formed on a blank 1 made of quartz, the dimensions of the monitor pattern 20 are measured, and then the blank 1 is sequentially subjected to anisotropic dry etching and isotropic wet etching to obtain a step. Parts 33A and 33B
Then, the monitor pattern 20 is removed from the blanks 1 on which the step portions 33A and 33B are formed, and the dimension of the specific region 25 defined by the step portion 33B immediately below the monitor pattern 20 is set as the overhang amount. It is made to measure.

Therefore, even if the PSM 100 is not cut and the cross section of the circuit pattern 10 is not observed, this circuit pattern 1
The canopy amounts Cx ′ and Cy ′ of 0 can be correctly grasped, and the quality of the canopy-type Levenson PSM 100 can be more surely guaranteed.

In this embodiment, the case where the dimensions of the monitor pattern 20 are measured before the anisotropic dry etching treatment has been described, but the dimensions of the monitor pattern 20 may be measured after the dry etching treatment. . Before the monitor pattern 20 is removed and before the shape of the monitor pattern 20 is damaged by an etchant or the like, the monitor pattern 20 is generated at any timing.
Can measure the dimensions of.

Further, it is not always necessary to measure the dimensions of the monitor pattern 20. For example, when the dimensional variation of the monitor pattern 20 is negligibly small with respect to the eaves amount 20A, the dimensional measurement of the monitor pattern 20 can be omitted.

(2) Embodiment FIG. 6 to FIG. 8 are process diagrams showing the eaves amount measuring method (parts 1 to 3) of the eaves-type Levenson PSM 200 according to the embodiment of the present invention. Here, it is premised that a plurality of isolated patterns having different dimensions are set as monitor patterns, and these isolated patterns are arranged side by side on the quartz blanks in the non-transfer region. Other conditions are the same as those in the above-described embodiment. Therefore, those having the same reference numeral have the same function, and the description thereof will be omitted.

First, as shown in FIG. 6A, a monitor pattern 20 composed of a plurality of isolated patterns having different dimensions.
Are formed on the blanks 1 in the non-transfer area. Further, similar to the embodiment, the circuit pattern 10 is formed on the blanks 1 in the transfer region at the same time as or before or after the formation of the monitor pattern 20.

As shown in FIG. 6A, the monitor pattern 20 in this embodiment has a plurality of isolated patterns 20 with fine line widths based on the desired target amount for eaves formation.
It is made of A to 20E.

For example, the target eaves amount is 10
0 nm. In this case, the isolated patterns 20A-2
0E is a rectangle and the length of one side is 180 nm to 300n
Set in the range of m. In FIG. 6A, the isolated pattern 2
The dimension of 0A is length × width = 300 nm × 300 nm. The size of the isolated pattern 20B is length × width = 27.
It is 0 nm × 270 nm. Similarly, the lengths of the isolated patterns 20C to 20E in the vertical direction and the horizontal direction are 3 respectively.
It is made different at 0 nm intervals. These isolated patterns 20A to 20E are arranged at intervals of 10 μm, for example.

Next, referring to FIG. 6A, the isolated pattern 20 is used.
Measure the vertical and horizontal line widths of A to 20E,
The difference (error) between the design value and the actual measurement value of these isolated patterns 20A to 20E is grasped. The line width is measured using SEM or the like as in the embodiment. Here, for convenience of explanation, the difference between the design value and the actual measurement value of each isolated pattern is set to zero.

Next, these isolated patterns 20A to 20
A resist pattern (not shown) is formed on E and the circuit pattern (not shown), and the blanks 1 are subjected to anisotropic dry etching using the resist pattern as a mask. As a result, as shown in FIG. 6B, the step portion 41 is formed between the individual isolated patterns. In FIG. 6B,
When the width of the step portion 41 between individual isolated patterns is L2, L2 is, for example, about 10 μm.

Next, the blank 1 is subjected to hydrofluoric acid treatment until the step portion 41 has a desired depth (for example, 171 nm). Then, as shown in FIG. 7A, the isolated patterns 20E, 20D, and 20C are sequentially erased in this order.

As shown in FIG. 7B, when the side etching amount for the blanks 1 reaches 1/2 of the line width of the isolated pattern, the blanks 1 of the base supporting the isolated pattern completely disappear. This is because it will end up.
In FIG. 7B, the blanks 1 of the base supporting the isolated patterns 20E and 20D have completely disappeared, and the isolated patterns 20
The blank 1 of the base supporting C is also made to the extent that the residue is slightly left.

Thereafter, the blanks 1 are subjected to an ashing process or the like to remove the resist pattern (not shown). Then, as shown in FIG. 8A, the blanks 1 are observed from above with an SEM or the like to measure the size of the residue 43 of the base supporting the isolated pattern 20C. In FIG. 8A, for example, when the horizontal dimension of the disappeared isolated pattern 20C is Z0 and the line width of the residue 43 is Z, Z0 =
240 nm and Z = 90 nm.

Here, as shown in FIG. 8A, since the isolated pattern 20C is side-etched from both ends (surroundings), by setting Ay = Z0 and By = Z in the equation, the side-etching of this hydrofluoric acid treatment is performed. The quantity can be calculated. C = (Z0-Z) / 2 ... '

From the equation, the side etching amount C, that is, the eaves amount of the isolated patterns 20C and 20B shown in FIG. 8B and the eaves amount of the circuit pattern (not shown) are 7
It is 5 nm.

In this method, as compared with the measuring method of the eaves amount described in the embodiment, it is not necessary to peel off the monitor patterns 20A to 20E by using FIB, laser or the like, so that the efficiency of measuring the eaves amount can be improved. Can be improved.

In advance, the individual monitor patterns 20A-
20E, these isolated patterns 20A to 20E
The line width of the base that supports the
It is advisable to investigate in advance the correlation (relationship) with the peeling of A to 20E from the base.

For example, in at least the isolated patterns 20C and 20B, if the line width of the base is reduced to 40% of the initial line width by side etching, the isolated patterns 20C and 20B are separated from the base. I was aware of. This data means that the isolated pattern 20C peels off when the side etching amount reaches 72 nm, and the isolated pattern 20B peels off when the side etching amount reaches 81 nm, as is clear from the equation. There is.

Here, looking at FIG. 8B, the isolated pattern 20C is peeled off, and the isolated pattern 20B is left without being peeled off. Therefore, it can be seen that the side etching amount (circuit pattern eaves amount) is in the range of 72 nm to 80 nm. In this method, the residue 43C of the isolated pattern
It is convenient because the range of the side etching amount can be known by observing the states of the isolated patterns 20A to 20E without the need to measure the dimension of (1) using a measuring device.

As described above, according to the canopy amount measuring method for the eaves-type Levenson PSMs 100 and 200 according to the present invention, time-consuming work such as cross-section observation of the PSM can be performed.
It has become possible to directly guarantee the eaves amount, not an indirect guarantee. Therefore, the quality of the PSM can be determined and the feedback to the manufacturing process of the PSM can be performed more accurately.

For example, as compared with the conventional method, it is possible to more accurately confirm whether or not the actual canopy amount of the eaves-type Levenson PSM can be produced within the washing resistance limit.
Further, when there is a problem in transferability, as a factor investigation, it is necessary to check whether the eaves amount is as designed or not.
It can be easily confirmed from the size of a specific region (base) immediately below the SM mask pattern.

[0059]

As described above, according to the method for measuring the eaves amount of the phase shift mask according to the present invention, after the light-shielding pattern and the monitor pattern of a predetermined size are formed on the substrate, the predetermined amount is formed on the substrate. An etching process is performed to form a stepped portion on the substrate, the monitor pattern is removed from the substrate on which the stepped portion is formed, and the dimension of the substrate surface in a specific area defined by the stepped portion directly below the monitor pattern is extended. It is made to measure as a quantity.

Therefore, even if the phase shift mask is not cut and the cross section of the light shielding pattern is not observed, the eave amount of the light shielding pattern can be correctly grasped, and the quality of the phase shift mask can be more surely guaranteed. You can

[Brief description of drawings]

1A and 1B are process diagrams showing a canopy amount measuring method (part 1) of a canopy-type Levenson PSM 100 according to an embodiment of the present invention.

2A and 2B are process drawings showing a method (part 2) for measuring an eaves amount of PSM100.

3A and 3B are process drawings showing a method (part 3) for measuring an eaves amount of PSM100.

4A and 4B are process drawings showing a method (part 4) for measuring an eaves amount of PSM100.

5A and 5B are process drawings showing a method (part 5) for measuring an eaves amount of PSM100.

6A and 6B are process diagrams showing a canopy amount measuring method (part 1) of a canopy-type Levenson PSM 200 according to an embodiment of the present invention.

7A and 7B are process drawings showing a method (part 2) of measuring an eaves amount of PSM200.

8A and 8B are process drawings showing a method (part 3) of measuring an eaves amount of PSM200.

9A and 9B are eaves-type Levenson P according to a conventional example.
It is process drawing which shows the amount measuring method of SM90.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Blanks (an example of a substrate), 10 ... Circuit patterns (an example of a light shielding pattern), 20 ... Monitor patterns, 20A, 20B, 20C, 20D, 20E ...
Isolated pattern, 25 ... specific area, 33A, 33B,
41 ... stepped portion, 100, 200 ... eaves-type Levenson PSM (an example of a phase shift mask)

Claims (6)

[Claims] 1. A method for measuring an eaves amount of a phase shift mask, comprising a step of forming a light-shielding pattern and a monitor pattern of a predetermined size on a substrate, and a substrate on which the monitor pattern and the light-shielding pattern are formed. A step of forming a step portion on the substrate by performing a predetermined etching process on the substrate, and removing the monitor pattern from the substrate on which the step portion is formed so that a specific region defined by the step portion directly below the monitor pattern is formed. And a step of measuring a dimension of a substrate surface as an eaves amount, a method for measuring an eaves amount of a phase shift mask. 2. The step of forming the light-shielding pattern and the monitor pattern of a predetermined size on the substrate includes a first step of forming the light-shielding pattern and the monitor pattern on the substrate, and a predetermined measuring device is used. 2. The method for measuring an eaves amount of a phase shift mask according to claim 1, further comprising a second step of measuring a dimension of the monitor pattern. 3. A step of measuring a dimension of a substrate surface of the specific region, and then calculating a side etching amount of the step portion from the measured dimension of the substrate surface of the specific region and the dimension of the monitor pattern. The method for measuring an eaves amount of a phase shift mask according to claim 1, further comprising: 4. The step of forming a stepped portion on the substrate, and then irradiating a focused ion beam or laser toward a monitor pattern on the substrate having the stepped portion to remove the monitor pattern. The method for measuring an eaves amount of a phase shift mask according to claim 1. 5. A case where a plurality of isolated patterns having different dimensions are used for the monitor pattern, wherein the light shielding pattern and the plurality of isolated patterns having a predetermined dimension are formed on the substrate, and then the isolated pattern is formed. The substrate on which the light-shielding pattern is formed is subjected to a predetermined etching process to form a step portion on the substrate, and a part of the isolated pattern is removed from the surface of the substrate by removing. A method for measuring an eaves amount of a phase shift mask according to. 6. For each of the isolated patterns having different dimensions, the relationship between the size of the substrate surface of the region supporting the isolated pattern and the separation of the isolated pattern from the substrate surface is investigated in advance, The substrate on which the isolated pattern and the light-shielding pattern are formed is subjected to a predetermined etching treatment to form a step portion on the substrate, and the isolated pattern is partially removed from the surface of the substrate and removed, and then removed. The method for measuring an eaves amount of a phase shift mask according to claim 5, wherein the dimension of the substrate surface of a specific region defined by the step portion directly below the isolated pattern is obtained from the result of the examination.