JPH0887103A - Correcting method for defect in phase shift mask - Google Patents

Abstract

PURPOSE: To obtain excellent dimensional accuracy and enough focus depth by filling a recessed defect with a light-shielding material in such a manner that variation in the resolution of the pattern to be formed on a wafer ranges within specified percentage of the designed dimension. CONSTITUTION: A phase shift mask 1 is produced by forming a phase shifter part 3 comprising Six , Ny as the shifter material on a quartz substrate 2 and having a recessed defect 5 in the edge part of the phase shifter part 3. This recessed defect is corrected by filling the recessed defect with carbon by FIB- assist deposition method. The recessed defect is corrected in such a manner that the pattern to be formed on a wafer by exposing through the mask after correction has variation in the resolution dimension in the range within π10% of the designed dimension. Thereby, the recessed defect 5 on the mask can be corrected without producing any new defect, and desired focus depth can be obtd. Moreover, even when the base body has steps, a pattern can be formed with good dimensional accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of correcting defects in a phase shift mask used in an exposure process of photolithography for fine processing of semiconductor devices.

[0002]

2. Description of the Related Art In recent years, with the high-density integration of LSIs, it is required that the pattern size in lithography technology be further miniaturized and the depth of focus be improved. Phase shift masks have been developed to meet such requirements, and the critical resolution in photolithography has been significantly improved. However, because of the high resolution, this phase shift mask also resolves defects of dimensions that are acceptable in the case of conventional Cr masks. Therefore, the defect on the phase shift mask needs to be corrected with higher accuracy.

Defects existing on a conventional photomask having a pattern of a light shield formed on a transparent substrate are usually repaired by the following method. For example, the correction of the concave defect is performed by assisted deposition using a focused ion beam (FIB) and a material gas such as pyrene.
It is performed by depositing carbon having a light transmittance of 0% on the defective portion. Further, the convex defect is repaired by removing the defective portion with a laser beam.

Defects on the conventional photomask can be corrected accurately and easily by such a method. As a phase shift mask, S is formed on a transparent substrate.
A halftone mask in which a phase softer portion made of a semitransparent material such as i _x N _y is formed. Si _x N _y
Although the transmissivity of is significantly different from the transmissivity of carbon, when the concave defect on the halftone mask for i-line (wavelength 365 nm) exposure is repaired by the conventional method, it is transferred onto the wafer through the corrected mask. It is known that the dimensions of the formed pattern are not greatly changed.

On the other hand, in a phase shift mask such as a halftone mask, the size of a bump defect to be corrected is smaller than that of a conventional photomask. Since the aperture diameter of the laser beam used for conventional convex defect correction is larger than the defect size existing in the phase shift mask, the convex defect existing on the halftone mask cannot be accurately corrected using the laser beam. It will be. Therefore, in order to remove the convex defects existing in the halftone mask, it is conceivable to use FIB etching which enables finer processing.

[0006]

However, as the exposure wavelength is shortened, the correction of the concave defect in the mask increases the influence on the pattern after transfer. For example, when a concave defect on a halftone mask for exposure to short wavelength light such as DeepUV is repaired by a conventional method, a repaired part in which carbon is embedded may be allowed as a new defect in the line width of a pattern after transfer. There is a risk of causing fluctuations.

On the other hand, when the convex defect existing in the halftone mask is repaired by sputtering using FIB, the surface exposed to the ion sputtering is damaged, so that the transmittance of this repaired portion may be lowered.
The transmittance decreases and the region becomes a new defect, which causes a variation in the pattern line width after transfer, as in the case where the concave defect is corrected.

When the pattern line width after the transfer has an unacceptable variation, the advantages of the phase shift mask which can form a fine pattern and improve the depth of focus cannot be sufficiently obtained.

Therefore, according to the present invention, the line width of the transfer pattern of the repaired portion after the defect is repaired does not vary by more than ± 10% of the design dimension, and the required depth of focus is obtained. It is an object of the present invention to provide a method of correcting a defect of a phase shift mask, which is capable of

[0010]

In order to solve the above-mentioned problems, the first invention (claim 1) comprises a translucent substrate and a semitransparent material formed on the surface of the translucent substrate. In the correction of the concave defect existing in the halftone mask having the phase shifter part, the fluctuation of the resolution size of the pattern formed on the wafer by performing the exposure through the corrected mask causes a change in the design size. Provided is a defect correcting method for a phase shift mask, which is characterized in that a light shielding body is filled in a concave defect portion within a range of ± 10% or less.

A second aspect of the present invention (claim 4) is a translucent substrate having a transparent conductive film formed on the surface thereof, and a phase shifter portion made of Si _x N _y formed on the transparent conductive film. In correcting a convex defect existing in a halftone mask having, a variation in resolution of a pattern formed on a wafer by performing exposure through the corrected mask is ± 10% or less of a design dimension. Provided is a defect correction method for a phase shift mask, characterized in that convex defects are removed by focused ion beam etching to the extent that

Further, a third invention (claim 6) is a convex defect existing in a halftone mask having a transparent substrate and a phase shifter portion made of Si _x N _y formed on the transparent substrate. In the correction, the focused ion beam and the gas are changed within a range in which the resolution of the pattern formed on the wafer by exposure through the corrected mask is within ± 10% of the design size. A defect repairing method for a phase shift mask, characterized in that the convex defect is removed by using the assisted etching used.

The present invention will be described in detail below. In the defect correcting method of the phase shift mask of the present invention, the concave defect represents a defect in which the pattern of the phase shifter portion is missing,
The convex defect represents a defect in which the shifter material remains in the region where the transparent substrate is to be exposed.

A normal photomask glass substrate can be used as a substrate constituting the phase shift mask used in the defect repairing method of the first invention. Specific examples thereof include quartz. The material of the shifter portion is not particularly limited as long as it is a semi-transparent material, but it is preferable to use, for example, Si _x N _y (x and y are integers).

As the phase shift mask, for example, a phase shifter portion formed with a line width of about 0.9 to 3.125 μm and a film thickness of about 100 nm, and a line width of about 1.375 to 1.6 μm.
A pentaploid mask with m openings can be used.

Carbon, chromium, etc. can be used as a light shield embedded in this portion in order to correct the concave defect. When embedding the light shield, a method such as FIB assist deposition can be used.

The defect repairing method of the first invention is a method in which a phase shifter section made of Si _x N _y is formed on a quartz substrate.
It is particularly effective in repairing defects existing on the halftone mask for deep UV exposure. In this case, it is preferable to fill the light shielding body in the concave defect portion with a width of 20% or more and 97% or less of the minimum dimension on the mask.

As the substrate constituting the phase shift mask used in the defect repairing method of the second invention, the same material as that described in the first invention can be used. Further, as the material of the transparent conductive film, SnO, Sb ₂ O ₃ ,
And a mixture of SnO and Sb ₂ O ₃ or the like can be applied.

For example, as the phase shift mask, a quintuple mask in which a mask pattern is formed on a quartz substrate through a transparent conductive film made of SnO with a film thickness of about 6 to 15 nm can be used. . The mask pattern has a line width of about 1.25 to 4.3 μm and a phase shifter portion having a film thickness of about 100 nm, and a line width of about 1.75 to 2.45 μm.
Can be formed from the opening.

The conditions of the focused ion beam (FIB) used for correcting the convex defect can be selected appropriately. In the second invention, it is preferable to remove the repaired portion by etching so as not to remove the transparent substrate surface. That is, it is preferable that the distance from the surface of the transparent substrate of the modified portion removed by etching is suppressed to the film thickness of the transparent substrate even at the maximum.

The defect repairing method of the second invention is particularly effective when applied to a phase shift mask for i-line (wavelength 365 nm) exposure. As the substrate forming the phase shift mask used in the defect repairing method of the third invention, the same materials as those described in the first and second inventions can be used.

The phase shift mask includes, for example, a phase shifter portion having a line width of about 0.9 to 3.125 μm and a film thickness of about 100 nm, and a line width of about 1.375 to 1.6 μm.
A pentaploid mask with m openings can be used.

FIB used to repair convex defects
The conditions and gas can be appropriately selected, and it is preferable that the corrected portion has a transmittance of 95% or more after the correction, and for example, XeF ₂ or the like can be used. In addition, as assist etching, G
The one using a ⁺ FIB and XeF ₂ may be adopted.

In the third aspect of the invention, it is preferable that the digging amount of the repaired portion into the transparent substrate portion is less than 30 ° in terms of phase difference. Here, the amount of digging is the transparent substrate surface exposed by removing the modified portion by etching,
It represents the distance to the original substrate surface.

[0025]

In the phase shift mask defect repairing method of the present invention, the variation in the resolution of the pattern formed on the wafer by exposing through the repaired mask is within ± 10% of the design size. The defect on the mask is corrected so that it can be contained inside.

Although it is ideal to accurately transfer the pattern with the size as designed, if the resolution of the pattern varies by ± 10% or less of the design size, it has little influence and is acceptable. It is within the range.

When the concave defect is to be repaired, the region repaired by embedding the light shield does not become a new defect, so that the pattern after transfer is affected when exposure is performed with short wavelength light. Absent. Further, in the case of correcting the convex defect, sputtering does not cause excessive damage to the substrate and the like existing under the convex defect, so that the transmittance of this portion is not lowered.

As described above, according to the method of the present invention, the concave defects and the convex defects on the mask can be repaired without causing new defects. When a wafer is subjected to pattern exposure through a phase shift mask modified by the method of the present invention, a desired depth of focus can be obtained, so that a pattern can be formed with high dimensional accuracy even if there is a step on the base. can do.

[0029]

The present invention will be described in more detail below by showing simulation results which are specific examples of the present invention. (Embodiment 1) In this embodiment, a phase shifter portion D using Si _x N _y as a phase shifter material is formed on a transparent substrate.
The concave defect generated on the halftone mask for deep UV exposure is corrected.

A mask pattern assumed in this embodiment is shown in FIG.
Shown in FIG. 1A shows a plan view of the mask pattern, and FIG. 1B shows a sectional view taken along line AA ′. As shown in FIG. 1, in the phase shift mask 1, Si _x N _{y is} used as a shifter material on the quartz substrate 2.
The phase shifter section 3 is formed. This mask is a pentaploid mask, and the light intensity transmittance of Si _x N _y 3 with respect to the quartz substrate 2 is 6% (amplitude transmittance of 24.
5%).

The mask pattern has an L / S in which the line width of the phase shifter portion 3 is 0.9 μm and the line width of the opening portion 4 is 1.6 μm.
The concave defect 5 is a pattern and exists at the edge portion of the phase shifter portion 3.

As shown in FIG. 2, the FIB is formed in the concave defect 5.
This is corrected by embedding carbon 6 by assist deposition. 2A shows a plan view of the phase shift mask 1 after the light shield 6 is embedded and corrected, and FIG. 2B shows a cross-sectional view taken along the line BB ′.

By changing the modified portion size d ₁ on the mask and embedding the light shield, the phase shift mask 1
FIG. 3 shows the simulation result of the resolution dimension on the wafer when the concave defect of No. 2 was corrected and the wafer was exposed to form a pattern using the corrected mask.

In the simulation, the exposure amount was assumed such that the finished size on the wafer was 0.25 μm and the resist pattern had a ratio of the resist size to the resist size of 1: 1. In addition, the exposure condition is the exposure wavelength 2
It was set to 48 nm (KrF light), numerical aperture (NA) 0.5, and coherence factor (σ) 0.5.

FIG. 3A shows the case of the just focus position, and FIG. 3B shows the defocus position ±.
The case of 0.5 μm is shown. The resolution dimension gradually decreases as the defect dimension d ₁ increases, as shown in FIG.
I understand from. In the method of the present invention, the defect is repaired so that the variation of the resolution dimension on the wafer is suppressed to ± 10% or less of the design dimension. Therefore, the repaired portion dimension d ₁ is 0.87 μm.
It can be seen that up to m is acceptable. That is, the upper limit of the embedding (correction) dimension for suppressing the line width variation of the pattern resolved using the corrected mask to be within ± 10% of the design dimension is 97% of the minimum dimension of the L / S pattern. It can be seen that it is.

20% of the minimum dimension of the L / S pattern
If the defect has the following size, the line width variation of the transfer pattern can be suppressed within ± 10% of the design size without correction.

Further, also in FIG. 3B showing the case of the defocus position ± 0.5 μm, the same result as in the case of the just focus position is obtained. That is, L /
By filling the light shield with a width of 97% or less of the minimum line width of the S pattern, the line width of the pattern formed using the mask in which the concave defect is corrected is suppressed to less than ± 10% of the design dimension. .

As in the case of the just focus position, the line width variation of the transfer pattern is kept within ± 10% of the design size for the size of 20% or less of the minimum size of the L / S pattern without correction. It can be suppressed.

From this, by setting the width dimension to be corrected by burying the light shielding body in the concave defect portion to be not less than 20% and not more than 97% of the minimum dimension of the L / S pattern, the depth of focus is 1.0 μm. It can be seen that (Embodiment 2) In the present embodiment, a convex defect generated on a halftone mask made of a phase shifter part using Si _x N _y as a phase shifter material on a transparent substrate is corrected by a focused ion beam (FIB). To do.

A mask pattern assumed in this embodiment is shown in FIG.
Shown in FIG. 4A shows a plan view of the mask pattern, and FIG. 4B shows a sectional view taken along the line CC ′. As shown in FIG. 3, in the phase shift mask 8, the conductive film 10 made of SnO is formed on the surface of the quartz substrate 9.
Is formed with a film thickness of 15 nm, and the phase shifter portion 12 made of Si _x N _y is formed on the conductive film 10. Combine the quartz substrate 9 and the conductive film 10,
It can be said to be a SnO / QZ substrate.

This mask is a pentaploid mask,
The light intensity transmittance of Si _x N _y on the SnO / QZ substrate is 4.8% (amplitude transmittance of 21.9%). The mask pattern has a side of the hole 13 of 2.45 μm,
The distance between the holes 13 is a contact hole (C / H) pattern in which the distance between the holes 13 is 4.3 μm.
Exists in the central part of.

To correct this convex defect 14, FIG.
As shown in (a) to (c), a simulation of the relationship between the defect dimension d ₂ and the resolution dimension on the wafer when etching and removing to a predetermined depth is performed.

FIG. 5A shows that when only the correction phase shifter portion 12 is removed by etching so that the surface of the conductive film 10 is not removed, FIG. 5B shows the surface of the translucent substrate 9. A cross-sectional view of the phase shift mask 8 in the case where a modified portion is removed by etching so as not to be removed is shown. Also, FIG.
FIG. 7C is a cross-sectional view of the phase shift mask 8 when the repaired portion is removed by etching so as to remove the transparent substrate 9. Here, the repaired portion is a convex defect 14 on the substrate.
Represents the area where is present.

The light transmittance and the phase difference in these three cases are as follows. The phase difference φ is shown in FIG.
It corresponds to the distance between the quartz substrate surface shown in (b) and (c) and the surface exposed by etching removal. .

Light transmittance T (%) Phase difference φ (°) In case of FIG. 5 (a) 98 0 In case of FIG. 5 (b) 98 15 In case of FIG. 5 (c) 76 21 In FIG. The dimension d ₂ and the simulation result of the resolution dimension on the wafer when a pattern is formed by exposing the wafer by using the mask in which the defect of this dimension is corrected are shown.

In the simulation, the finished size of the holes on the wafer was 0.45 μm, and the exposure amount was assumed to be a resist pattern in which the ratio of the hole size to the resist size was 1: 2. The exposure conditions were an exposure wavelength of 365 nm (i-line), a numerical aperture (NA) of 0.5, and a coherence factor (σ) of 0.6.

FIGS. 6A, 6B, and 6C show the case where only the phase shifter 12 is removed, the conductive film 10 is removed, and the quartz substrate 9 is removed. Represents the resolution dimension of. That is,
FIGS. 6A to 6C are respectively the above-described FIGS.
This corresponds to the case of (c).

In FIG. 6, the solid line shows the case of the just focus position, and the broken line shows the defocus position ± 0.
The case of 75 μm is shown. As shown in FIG. 6A, when only the phase shifter portion 12 is removed by etching from the repaired portion, the resolution dimension hardly changes regardless of the design dimension even if the defect dimension d ₂ increases. That is, the resolution dimension on the wafer is within ± 10% of the design dimension. In particular, even at the defocus position of ± 0.75 μm, a resolution dimension within ± 10% of the design dimension can be obtained, and it can be seen that a depth of focus of 1.5 μm can be achieved.

As shown in FIG. 6B, the quartz substrate 9
Even if the repaired portion is removed by etching up to the interface between the conductive film 10 and the quartz substrate 9 so as not to remove the impurities, as shown in FIG.
As in the case of (a), regardless of the defect size,
Even if the defocus position is ± 0.75 μm, the variation of the resolution dimension is within ± 10% of the design dimension.

On the other hand, as shown in FIG.
When the quartz substrate 9 is also removed by etching, the variation in the hole resolution size increases as the defect size d ₂ increases. In this case, even at the just focus position, if the correction dimension d ₂ exceeds about 1.71 μm, the resolution dimension exceeds ± 10% of the design dimension. Furthermore, when the defocus position is ± 0.75 μm, it is about 0.46 μm.
When the corrected size of m is exceeded, the resolution size is ± 10 of the design size.
%, The focal depth of 1.5 μm cannot be achieved.

In the method of the present invention, the modified portion is etched up to the conductive film so that the surface of the quartz substrate is not removed, so that the variation of the resolution dimension on the wafer is reduced to ± 10% or less of the design dimension. Suppresses focus depth of 1.5 μm
Can be achieved.

Do not remove the surface of the quartz substrate,
When the repaired portion is removed by etching, the defect dimension d ₂
Is 2.45 × 2.45 μm, the pattern is resolved on the wafer with dimensions within the above range. Therefore, it can be seen that the region to be opened as a hole can be corrected even if it is completely filled with the phase shifter material.

In this embodiment, the simulation was conducted with the conductive film 10 having a film thickness of 15 nm.
Etching without removing the quartz substrate can be applied regardless of the film thickness of the conductive film 10. (Embodiment 3) In this embodiment, a convex defect generated on a deep exposure halftone mask made of a phase shifter portion using Si _x N _y as a phase shifter material on a transparent substrate is treated with FIB and gas. It is corrected by scraping with the assist etching used. When this method is used, the transmittance of the corrected portion after the correction is 95% or more.

FIG. 7 shows the mask pattern assumed in this embodiment.
Shown in FIG. 7A shows a plan view of the mask pattern, and FIG. 7B shows a sectional view taken along the line D-D '.
As shown in FIG. 7, in the phase shift mask 16,
A phase shifter portion 18 made of Si _x N _y is formed on the quartz substrate 17. This mask is a pentaploid mask, and the light intensity transmittance of Si _x N _y with respect to the quartz substrate 17 is 6% (amplitude transmittance 24.5%).

In the mask pattern, one side of the holes 19 is 1.375 μm, and the space between the holes 19 is 3.125 μm.
In the contact hole (C / H) pattern, the convex defect 20 is located at the center of the hole 19.

This convex defect 20 is corrected by etching to a predetermined phase difference as shown in FIG.
Note that FIG. 8A shows a plan view of the mask after correction,
FIG. 8B shows a cross-sectional view taken along line EE ′, and the phase difference φ corresponds to the distance between the surface of the quartz substrate and the surface exposed by etching removal. As shown in FIG. 8, the correction defect 2 is removed by removing the convex defect 20.
1 is exposed.

The convex defect on the phase shift mask 16 is corrected by changing the defect size d ₃ on the mask to remove the defect, and the wafer is exposed by using the corrected phase shift mask to form a pattern. FIG. 9 shows the simulation result of the resolution dimension on the wafer when forming the.

In the simulation, it is assumed that the exposure amount is such that the finished dimension of the hole on the wafer is 0.3 μm, and the dimension of the hole portion and the dimension of the resist portion are 1: 2. Also, the exposure condition is an exposure wavelength of 24
8 nm (KrF light), numerical aperture (NA) 0.5, and coherence factor (σ) 0.5.

9 (a), 9 (b) and 9 (c) show the digging amount of the convex defect repaired portion with a phase difference of 0 ° and 2 °, respectively.
The resolution dimension is shown when the transparent substrate is removed by etching so as to be 0 ° and 30 °.

In FIG. 9, the solid line shows the case of the just focus position, and the broken line shows the defocus position ± 0.
The case of 5 μm is shown. As shown in FIG. 9A, when the translucent substrate is removed by etching to a phase difference of 0 °,
Even if the defect dimension d ₃ increases, the resolution dimension hardly changes regardless of the defect dimension. That is, the resolution dimension on the wafer is within ± 10% of the design dimension.
In particular, even at a defocus position of ± 0.5 μm, a resolution dimension within ± 10% of the design dimension can be obtained, so it can be seen that a depth of focus of 1.0 μm can be achieved.

It can be seen from FIG. 9B that a depth of focus of 1.0 μm can be achieved even when the translucent substrate is removed by etching to a phase difference of 20 °. That is, when the defocus position is ± 0.5 μm, the variation of the resolution dimension is slightly large, but is within ± 10% of the design dimension.

However, as shown in FIG. 9 (c),
When the translucent substrate is removed by etching up to the phase difference of 30 °, the hole resolution size varies greatly at the defocus position ± 0.5 μm as the defect size d ₃ increases. That is, it is understood that the dug of the translucent substrate exceeded the allowable range.

In the method of the present invention, the phase difference is 30 °.
By etching the light-transmissive substrate at the repaired portion so that it becomes less than 1, the variation of the resolution of the wafer is ± 1 of the design dimension.
It can be suppressed to less than 0% and a focal depth of 1.0 μm can be achieved.

When the translucent substrate in the repaired portion is removed by etching so that the phase difference is less than 30 °, even if the defect dimension d ₃ is 1.375 μm × 1.375 μm,
A pattern is resolved on the wafer with dimensions within the range. Therefore, it can be seen that even if the region to be opened as a hole is completely filled with the phase shifter material, it can be corrected.

[0065]

As described in detail above, according to the present invention,
There is provided a method of correcting a defect of a phase shift mask, in which a line width variation of a transfer pattern of a corrected portion after the correction is within ± 10% of a design dimension. The pattern resolved using the mask thus modified has excellent dimensional accuracy and a sufficient depth of focus. Such a defect correction method for a phase shift mask is effective in a lithographic technique such as fine processing of electronic parts, and its industrial value is great.

[Brief description of drawings]

FIG. 1 is a view showing a phase shift mask having a concave defect which is repaired by a defect repairing method of the present invention.

FIG. 2 is a view showing a phase shift mask after correcting a concave defect.

FIG. 3 is a diagram showing a relationship between a corrected partial defect size and a resolution size.

FIG. 4 is a diagram showing a phase shift mask having a convex defect that is repaired by the defect repairing method of the present invention.

FIG. 5 is a cross-sectional view of a phase shift mask after correcting a convex defect.

FIG. 6 is a diagram showing a relationship between a corrected partial defect size and a resolution size.

FIG. 7 is a diagram showing a phase shift mask having a convex defect which is repaired by the defect repairing method of the present invention.

FIG. 8 is a view showing a phase shift mask after correcting a convex defect.

FIG. 9 is a diagram showing a relationship between a corrected partial defect size and a resolution size.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Phase shift mask, 2 ... Quartz substrate, 3 ... Phase shifter part, 4 ... Opening part 5 ... Recessed defect, 6 ... Light-shielding body, 8 ... Phase shift mask, 9 ...
Quartz substrate 10 ... SnO film, 11 ... Transparent substrate, 12 ... Phase shifter section, 13 ... Hole 14 ... Convex defect, 16 ... Phase shift mask, 17 ... Quartz substrate 18 ... Phase shifter section, 19 ... Hole, 20 ... Convex defect, 2
1 ... correction part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Soichi Inoue No. 1, Komukai Toshiba-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Corporate Research & Development Center

Claims (7)

[Claims] 1. A method for repairing a concave defect existing in a halftone mask having a transparent substrate and a phase shifter portion made of a semi-transparent material formed on the surface of the transparent substrate, A phase characterized by burying a light-shielding body in a concave defect portion within a range in which a variation in resolution of a pattern formed on a wafer by exposure through a mask is within ± 10% of a design dimension. Shift mask defect correction method. 2. The method of correcting a defect of a phase shift mask according to claim 1, wherein the phase shifter portion of the halftone mask is made of Si _x N _y (x and y are integers). 3. The halftone mask is DeepUV
3. The phase according to claim 2, which is an exposure mask, and a width of a repair portion in which a light shield is embedded to repair the concave defect is in a range of more than 20% and 97% or less of a minimum line width of the mask pattern. Shift mask defect correction method. 4. A convex defect existing in a halftone mask having a light-transmissive substrate having a transparent conductive film formed on its surface and a phase shifter portion made of Si _x N _y formed on the transparent conductive film. In correcting the pattern, the resolution change of the pattern formed on the wafer by exposing through the corrected mask is
A method of repairing defects in a phase shift mask, characterized in that convex defects are removed by etching using a focused ion beam within a range of 10% or less. 5. The method of repairing a defect of a phase shift mask according to claim 4, wherein the repaired portion is removed by etching using a focused ion beam so that the surface of the transparent substrate is not removed. 6. A method of repairing a convex defect existing in a halftone mask having a transparent substrate and a phase shifter section made of Si _x N _y formed on the substrate, in which a repaired mask is used. Variation in the resolution of the pattern formed on the wafer due to exposure
A defect repairing method for a phase shift mask, characterized in that the convex defects are removed by assisted etching using a focused ion beam and a gas so as to be 10% or less. 7. The method of repairing a defect of a phase shift mask according to claim 6, wherein a digging amount of the repaired portion into the transparent substrate is less than 30 ° in terms of phase difference.