JP5691677B2 - Method for correcting phase defect of reflective photomask - Google Patents

Description

  The present invention relates to a method for correcting a phase defect in a mask pattern of a reflective photomask using extreme ultraviolet light or the like used in the manufacture of a semiconductor integrated circuit or the like.

  The miniaturization of semiconductor devices is progressing year by year, and accordingly, light used in photolithography technology is also being shortened. That is, the KrF excimer laser (wavelength 248 nm), which has been used as a conventional light source, is shifted to an ArF excimer laser (wavelength 193 nm). In recent years, immersion exposure methods and double exposure methods using an ArF excimer laser have been studied. It is active. On the other hand, research and development of EUV lithography using a reflection-type optical system using extreme ultraviolet rays (Extreme UV, hereinafter abbreviated as EUV) whose wavelength is one digit or more shorter than that of an excimer laser is in progress.

  Along with the shortening of the wavelength of the light source, there is an increasing demand for miniaturization and high precision in photomasks used for transferring patterns to semiconductor wafers. Conventionally, the photomask is a light transmission type until ArF exposure, but the EUV light has a small difference in refractive index of the material and the refraction type optical system cannot be used. A reflection type is also used for the exposure photomask.

  In general EUV masks that have been developed so far, a multilayer film portion in which about 40 to 50 pairs of two-layer films are laminated on a Si wafer or glass substrate is used as a high reflection region, and a low reflection region (absorption region) is formed thereon. ) As a metal film pattern. The high reflection region is a multilayer film in which two kinds of films (for example, Mo and Si) having a large difference in refractive index and absorption as small as possible are alternately laminated. As a result, a slight reflection component from each layer pair interferes and strengthens, and it is possible to obtain a relatively high reflectivity with respect to EUV light close to normal incidence. Usually, in order to protect the multilayer film, a film made of Si or the like having high transparency to EUV light is formed as a capping film on the uppermost layer of the multilayer film (a layer close to the absorption film).

  A photomask is inspected before a circuit pattern is baked and transferred onto a semiconductor wafer, but if there are minute foreign objects or defects between the circuit patterns, the circuit pattern is not normally transferred due to the foreign objects or defects, A semiconductor device becomes defective. This problem has become more apparent with the recent high integration of semiconductor devices, and the presence of finer foreign matters and defects has become unacceptable.

Usually, a photomask is required to have no pattern defects, and mask inspection and correction techniques at this stage are important. In general, a defect in a photomask should have a light-shielding film (an absorption film in an EUV mask) where there should be a light-shielding film (an absorption film in an EUV mask), and an excess in a transmission region (a high-reflection region in an EUV mask). There is a black defect in which the light shielding film (absorbing film) remains.
In addition to the general photomask defects as described above, there is a phase defect as a defect peculiar to the EUV mask. As described above, the EUV mask forms a highly reflective region by the interference light of the multilayer film laminated on the substrate. If there are protrusions (particles) or pits on the substrate or in the multilayer film, The reflected light has a phase difference with respect to the reflected light from the normal high reflection region, and is accompanied by a decrease in reflectance. Such a defective portion is called a phase defect.

An example of a typical phase defect of an EUV mask will be described with reference to FIG. FIG. 3 is a partial cutout of the phase defect portion of the EUV mask. Here, a protrusion defect (particle) 3 made of Si exists on the substrate 1 ′, and a multilayer film 2 made of Mo and Si is laminated thereon. The uppermost layer of the multilayer film 2 is a capping film (not shown in FIG. 3) for protecting the multilayer film. The height of the portion 4 of the multilayer film raised by the protrusion defect 3 is usually lower than the height of the protrusion defect 3. This is because the thickness of each layer (Mo, Si) of the multilayer film formed on the protrusion defect part is about several percent thinner than the film thickness formed on the normal part.

  FIG. 4A schematically shows an EUV mask having a phase defect as shown in FIG. 4A also shows a capping film 2a made of Si or the like as a part of the multilayer film. In the EUV mask as shown in FIG. 4A, the reflectance and reflection of the reflected light 5 from the normal high reflection region and the reflected light 6 from the defect portion at 13.52 nm, which is a typical EUV exposure wavelength. When the phase difference between the light 5 and the reflected light 6 is calculated with the height of the Si protrusion as the horizontal axis, the results are as shown in FIGS. Here, the thickness of each layer (Mo, Si) of the multilayer film formed on the protrusion defect part is calculated as 2% thinner than the film thickness formed on the normal part.

  As can be seen from FIG. 4B, in the defect portion, the thickness of each layer (Mo, Si) of the multilayer film formed thereon is 2% thinner than the normal film thickness. The reflectance Rd by the light 6 is about 10% lower than the reflectance Rm by the reflected light 5. This does not depend on the defect height (horizontal axis) as long as there is a defect directly above the substrate and a minute defect (about several nm). On the other hand, as can be seen from FIG. 4C, it can be seen that the phase difference between Rm and Rd increases rapidly with the height of the defect even in a minute protrusion defect.

  FIG. 5 schematically illustrates an EUV mask having a protrusion defect in the middle of the multilayer film. Here, the protrusion defect 3 ′ is present in the middle of the multilayer film 2 ′. Accordingly, since the number of layers of the multilayer film that is thinner than the multilayer film of the normal part above the defect is smaller than when the defect is directly above the substrate, the height of the part 4 ′ of the multilayer film raised by the defect 3 ′ is This is lower than when the defect is directly above the substrate. However, the fact that the reflectance of the reflected light 6 ′ is lower than the reflectance of the reflected light 5 and that a phase difference occurs between the reflected light 5 and the reflected light 6 ′ causes a phase defect. It is the same as in some cases.

  As described above, the phase defect of the reflective mask involves not only the phase difference between the defective part and the non-defect (normal) part, but also the reflectance difference. Now, there are various variations depending on the material, and no method has been specifically proposed to fix and solve them extensively.

JP 2006-60059 A JP 2007-27035 A International Publication No. 2007/102333 Pamphlet

Supervised by Koichi Toyoda and Shinji Okazaki: Development and application of EUV light source, CM Publishing, ISBN: 4882316668, 2007

  The present invention provides a method for correcting a phase defect in a reflective mask, which is made under the circumstances as described above, and enables the phase defect to be corrected with high accuracy without damage to the reflective mask. For the purpose.

The present invention described in claim 1
A method of correcting a phase defect generated in a highly reflective portion of a reflective photomask in which Mo and Si are alternately laminated to form a multilayer film,
By laminating a multilayer film made of two kinds of materials, one of which is Si (silicon), on the phase defect portion, the phase difference between the phase defect portion and the high reflection portion is practically 0 (zero), In practically equalizing the reflectance of the defective part and the reflectance of the highly reflective part,
The film thickness per layer of Si (silicon) laminated on the phase defect portion is different from the film thickness per layer of Si used for the high reflection portion.

The present invention described in claim 2
The other of the two types of materials laminated on the phase defect portion is Mo (molybdenum).

The present invention according to claim 3 provides:
The other of the two types of materials laminated on the phase defect portion is Ru (ruthenium).

The present invention according to claim 4 provides:
The multilayer film laminated on the phase defect portion is laminated after the capping film of the phase defect portion is peeled off.

  According to the fifth aspect of the present invention, the multilayer film laminated on the phase defect portion is laminated after peeling off the capping film of the phase defect portion and a part of the multilayer film under the capping film. It is characterized by that.

  The multilayer film laminated on the phase defect portion may be formed by peeling a capping film of the phase defect portion, a multilayer film under the capping film, and a defect below the multilayer film. It is characterized by being laminated on.

  According to the phase defect correcting method for a reflective mask of the present invention, a multilayer film made of two kinds of suitable materials is applied to the phase defect portion according to the decrease in the reflectance of the defect portion and the phase difference. Since they are formed by numbers, the reflectance and the phase difference can be corrected with high accuracy.

It is a cross-sectional schematic diagram which shows the correction | amendment part of the reflective mask corrected by the phase defect correction method in connection with embodiment of this invention. It is a cross-sectional schematic diagram which shows the correction part of another reflection type mask corrected by the phase defect correction method in connection with embodiment of this invention. It is a cross-sectional schematic diagram which shows a part of reflective mask with a phase defect. It is a cross-sectional schematic diagram (a) which shows the reflection type mask with a phase defect, and a characteristic view which shows the result of having calculated the reflectance (b) and phase difference (c) at this time. It is a cross-sectional schematic diagram which shows another reflection type mask with a phase defect. It is a table | surface which shows the optical constant (refractive index, extinction coefficient) in wavelength 13.53nm of the material used in order to calculate a reflectance and a phase difference. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention. It is a characteristic view which shows the result of having calculated the phase difference and the reflectance for calculating | requiring the film thickness of the multilayer film for correction which concerns on the phase defect correction method of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the embodiments, the same components are denoted by the same reference numerals, and redundant description in the embodiments is omitted.
(Embodiment)
FIG. 1 is a view schematically showing a cross section after correcting a phase defect portion of an EUV mask by the method of the present invention. Here, the protrusion defect 3 is located immediately above the substrate 1 ′, and the multilayer film 2 is laminated thereon. The uppermost layer of the multilayer film 2 is a capping layer made of Si or the like (not shown in the figure). Further, reference numeral 7 denotes a multilayer film laminated for correcting phase defects. The correction multilayer film 7 is laminated on the capping film of the multilayer film 2, or depending on the reflectivity and phase difference, the capping film of the phase defect portion or the upper pair of the multilayer film 2 is covered. It is laminated on the peeled.

  FIG. 2 is a view schematically showing a cross section after another phase defect portion of the EUV mask is corrected by the method of the present invention. Here, the protrusion defect 3 'exists in the middle of the multilayer film 2'. The uppermost layer of the multilayer film 2 'is a capping layer made of Si or the like (not shown in the figure). Further, 7 'is a multilayer film laminated to correct the phase defect. The correcting multilayer film 7 ′ is laminated on the capping film of the multilayer film 2 ′, or depending on the reflectivity and phase difference, up to the capping film of the phase defect portion, or the upper number of the multilayer film 2 ′. It is laminated after peeling up to the pair or up to the defect 3 ′.

Hereinafter, the results of confirming that the phase defect correcting method of the present invention is effective by calculating the reflectance and the phase difference according to the optical thin film theory will be shown. In the calculation, the wavelength is 13.52 nm, which is typical for EUV exposure, and the values shown in FIG. 6 are used as the optical constants of the thin film material. Moreover, 50 pairs of Mo / Si multilayer films for high reflection (the film thickness in each layer is S: 4.16 nm, Mo: 2.80 nm), the capping film is a general Si: 11 nm thickness, and the material of the protrusion defect is The thickness of each layer of the multilayer film formed on Si and the protrusion defect part was calculated as 2% thinner than the film thickness formed on the normal high reflection part. Some variation does not affect the effectiveness of the method of the present invention.

  The above-described reflectance and phase difference were calculated by calculating the reflectance and phase difference after forming the correction multilayer film in the phase defect portion by the method of the present invention. At this time, when the protrusion defect is directly above the substrate (FIG. 4A), the protrusion defect is divided into the case where it is in the center of the normal high reflection multilayer film (FIG. 5). The horizontal axis of the calculation diagram is the film thickness per layer of one material of the correction multilayer film. At this time, the total film thickness per pair of the correction multilayer film was the same as that of the normal Mo / Si multilayer film. This is because it is theoretically known that the total film thickness at which the reflectance is improved by the interference is almost a half wavelength regardless of the material.

  FIG. 7 shows a normal height when 19 pairs of correction multilayer films made of Si and Mo are stacked in the phase defect portion when there is a phase defect made of Si protrusions (particles) having a height of 3 nm directly above the substrate. The phase difference between the reflected light 5 from the reflection region and the reflected light 8 from the correction unit (see FIG. 1), and the reflectance Rm by the reflected light 5 and the reflectance Rd by the reflected light 8 per layer of the Si film for correction It shows the result of calculation with the film thickness of as a horizontal axis. In the phase difference diagram, a “jump” occurs between 0 ° and 360 °, but this is due to the display on the software used for the calculation and is actually continuous. As can be seen from FIG. 7, the phase difference between the reflected light 5 and the reflected light 8 becomes substantially zero when the thickness of the Si film for correction is approximately 4 nm, and the reflectance Rd of the defect portion is a normal portion. It can be seen that the correction is made almost equal to the reflectance Rm.

  FIG. 8 shows that when there is a phase defect consisting of a Si protrusion having a height of 5 nm directly above the substrate, a capping film having a thickness of Si: 11 nm in the phase defect portion is peeled off, and then a correction multilayer film made of Si and Mo is formed. When 27 pairs are stacked, the phase difference between the reflected light 5 and the reflected light 8 (see FIG. 1), and the reflectance Rm by the reflected light 5 and the reflectance Rd by the reflected light 8 are obtained for each layer of the Si film for correction. The results of calculation with the film thickness as the horizontal axis are shown. As can be seen from FIG. 8, the phase difference between the reflected light 5 and the reflected light 8 is substantially zero when the thickness of the Si film for correction is approximately 3.5 nm, and the reflectance Rd of the defect portion is It can be seen that the correction is made almost equal to the reflectance Rm of the normal part.

  FIG. 9 shows reflected light 5 when 19 pairs of correction multilayer films made of Si and Ru (ruthenium) are laminated on the phase defect portion when there is a phase defect made of a Si protrusion having a height of 3 nm directly above the substrate. And the phase difference between the reflected light 8 (see FIG. 1), and the reflectance Rm by the reflected light 5 and the reflectance Rd by the reflected light 8 are calculated with the film thickness per layer of the correction Si film as the horizontal axis. It is shown. As can be seen from FIG. 9, when the thickness of the Si film for correction is approximately 4.4 nm, the phase difference between the reflected light 5 and the reflected light 8 is substantially 0, and the reflectance Rd of the defect portion is It can be seen that the correction is made almost equal to the reflectance Rm of the normal part.

  FIG. 10 shows that when there is a phase defect composed of a Si protrusion having a height of 5 nm directly above the substrate, a correction multilayer film composed of Si and Ru is removed after removing the capping film composed of Si: 11 nm thick in the phase defect portion. The phase difference between the reflected light 5 and the reflected light 8 (see FIG. 1) and the reflectance Rm due to the reflected light 5 and the reflectance Rd due to the reflected light 8 when the layers are laminated are determined as a film per layer of the Si film for correction. The results of calculation with the thickness as the horizontal axis are shown. As can be seen from FIG. 10, the phase difference between the reflected light 5 and the reflected light 8 becomes substantially zero when the thickness of the Si film for correction is approximately 4.2 nm, and the reflectance Rd of the defect portion is It can be seen that the correction is made almost equal to the reflectance Rm of the normal part.

  FIG. 11 shows that when there is a phase defect consisting of a Si protrusion having a height of 3 nm at the center of the multilayer film, the phase defect part is made of Si and Mo after peeling the capping film made of Si: 11 nm thick. When 21 pairs of correction multilayer films are laminated, the phase difference between the reflected light 5 from the normal high reflection region and the reflected light 8 ′ from the correction portion (see FIG. 2), and the reflectance Rm and reflection by the reflected light 5 The reflectance Rd by light 8 'shows the result of having calculated the film thickness per layer of Si film for correction | amendment with a horizontal axis. As can be seen from FIG. 11, when the thickness of the Si film for correction is approximately 3.7 nm, the phase difference between the reflected light 5 and the reflected light 8 ′ becomes substantially zero, and the reflectance Rd of the defect portion. Is substantially equal to the reflectance Rm of the normal part, and it can be seen that correction is made.

  FIG. 12 shows reflected light 5 and reflected light 8 ′ when 25 pairs of correction multilayer films made of Si and Mo are laminated when there is a phase defect made of a Si protrusion having a height of 5 nm at the center of the multilayer film. The phase difference of (refer FIG. 2) and the result of having calculated the reflectance Rm by the reflected light 5 and the reflectance Rd by the reflected light 8 'by setting the film thickness per one layer of the Si film for correction to the horizontal axis. is there. As can be seen from FIG. 12, when the thickness of the Si film for correction is approximately 3.9 nm, the phase difference between the reflected light 5 and the reflected light 8 ′ becomes substantially zero, and the reflectance Rd of the defect portion. Is substantially equal to the reflectance Rm of the normal part, and it can be seen that correction is made.

  FIG. 13 shows reflected light 5 and reflected light 8 ′ when 25 pairs of correction multilayer films made of Si and Ru are laminated when there is a phase defect consisting of a Si protrusion having a height of 5 nm in the center of the multilayer film. The phase difference of (refer FIG. 2) and the result of having calculated the reflectance Rm by the reflected light 5 and the reflectance Rd by the reflected light 8 'by setting the film thickness per one layer of the Si film for correction to the horizontal axis. is there. As can be seen from FIG. 13, the phase difference between the reflected light 5 and the reflected light 8 ′ becomes substantially zero when the thickness of the Si film for correction is about 4.3 nm, and the reflectance Rd of the defect portion. Is substantially equal to the reflectance Rm of the normal part, and it can be seen that correction is made.

  The phase difference and reflectivity of the phase defect portion vary depending on the position, size, and material of the causal protrusion (particle) defect. Therefore, depending on the situation, it may be better to laminate not only the capping film of the phase defect portion but also the upper several pairs of the multilayer film below it, and then laminating the correction multilayer film. FIG. 14 shows that when there is a phase defect consisting of a Si protrusion having a height of 5 nm directly above the substrate, the capping film made of Si: 11 nm thick in the phase defect portion is peeled off, and a 2% thin multilayer film thereunder is further removed. After the peeling, the phase difference between the reflected light 5 and the reflected light 8 (see FIG. 1) and the reflectance Rm by the reflected light 5 when 30 pairs of correction multilayer films made of Si and Ru are laminated on the phase defect portion The result of calculating the reflectance Rd by the reflected light 8 with the film thickness per layer of the Si film for correction as the horizontal axis is shown. As can be seen from FIG. 14, when the thickness of the Si film for correction is approximately 4.8 nm, the phase difference between the reflected light 5 and the reflected light 8 is substantially 0, and the reflectance Rd of the defect portion is It can be seen that the correction is made almost equal to the reflectance Rm of the normal part.

  Protrusion (particle) defects that cause phase defects usually become black defects (or amplitude defects) as the position of the defects is closer to the surface of the multilayer film and as the material absorbs more EUV light. It will be close. In this case, the reflectivity is greatly lowered, and the phase difference from the highly reflective portion remains. In such a case, it is more effective to stack the multilayer film for correction after the defect itself is peeled off as well as the capping film of the defective portion and the thin multilayer film. FIG. 15 shows that when there is a Si protrusion on the 10th layer from the top of the 2% thin multilayer film, the capping film having a Si: 11 nm thickness at the phase defect portion is peeled off, and then 10 pairs of the thin multilayer films thereunder are separated. The phase difference between the reflected light 5 and the reflected light 8 ′ (see FIG. 2) and the reflected light 5 when the pair of correction multilayer films made of Si and Ru are laminated after peeling and further removing the projection defect itself. 2 shows the result of calculation of the reflectance Rm by the reflected light and the reflectance Rd by the reflected light 8 ′ with the film thickness per layer of the correction Si film as the horizontal axis. As can be seen from FIG. 15, the phase difference between the reflected light 5 and the reflected light 8 ′ becomes almost zero when the thickness of the Si film for correction is about 4.3 nm, and the reflectance Rd of the defect portion. Is substantially equal to the reflectance Rm of the normal part, and it can be seen that correction is made.

As a method for forming a correction multilayer film in the present invention, a white defect correction method in a conventional transmission type photomask can be applied. First, the pattern surface is scanned by FIB (focused ion beam) focused in advance by transfer exposure, optical measurement, or sub-micron order, and secondary electrons emitted from the surface are detected to form a scanned ion image on the display. The phase defect portion is specified by grasping. Next, a gas including a material to be formed for correction is introduced into the irradiation processing chamber, and the phase defect portion is irradiated with FIB to form a correction multilayer film while decomposing the gas. Examples of gases include SiH (CH ₃ ) ₃ for Si-based films, ruthenium carbonyl (Ru ₃ (CO) ₁₂ ) for forming Ru (ruthenium) films (Patent Document 2), and pentadienyl compounds of ruthenium (patents). Reference 3), organic gases containing metals or semiconductor elements such as carbon-based gases such as styrene and pyrene for forming C (carbon film) can be used.

In the present invention, before forming a correction multilayer film, a black defect in a conventional transmissive photomask is also obtained when a capping film, a thin multilayer film depending on the phase difference and reflectivity, and a protrusion defect are peeled off in advance. A correction method can be applied. That is, a method of scraping using a probe of an atomic force microscope having a probe harder than a film to be peeled off, a method of irradiating a pattern surface with FIB and ejecting atoms and molecules on the surface into a vacuum (sputtering phenomenon), Alternatively, the film to be peeled can be removed by a method in which an etching gas such as chlorine (Cl ₂ ) gas is decomposed and reacted with FIB.

  The present invention can be widely applied to the correction of phase defects existing in the high reflection portion of a reflective photomask for EUV exposure, etc. used in the manufacture of semiconductor integrated circuits and the like.

DESCRIPTION OF SYMBOLS 1 ... Reflective type mask substrate 1 '...... Part of the reflective type mask substrate 2 ... Multilayer film 2' having a projection defect immediately above the substrate ... Multilayer film 2a having a projection defect at the center of the multilayer film ... Capping film 3 ... Protrusion defect 3 'directly above the substrate .... Protrusion defect 4 in the center of the multilayer film .... Multilayer film portion 4' raised due to the protrusion defect directly above the substrate .... Multilayer film raised due to the protrusion defect in the center of the multilayer film. Part 5 …… Reflected light 6 of the highly reflective part …… Reflected light 6 ′ raised due to the protrusion defect right above the substrate 6 …… Reflected light 7 swelled due to the protrusion defect at the center of the multilayer film 7 Portion 7 'corrected phase defect due to protrusion 8 ... Portion corrected phase defect due to protrusion at the center of the multilayer film 8 Reflected light 8' corrected phase defect due to protrusion directly above the substrate 8 '... Reflected light at the part where phase defects due to protrusions are corrected

Claims (6)

A method of correcting a phase defect generated in a highly reflective portion of a reflective photomask in which Mo and Si are alternately laminated to form a multilayer film ,
By laminating a multilayer film made of two kinds of materials , one of which is Si (silicon) , on the phase defect portion, the phase difference between the phase defect portion and the high reflection portion is practically 0 (zero), and the phase In practically equalizing the reflectance of the defective part and the reflectance of the highly reflective part ,
The phase of a reflective photomask characterized in that the film thickness per layer of Si (silicon) laminated on the phase defect portion is different from the film thickness per Si layer used in the high reflection portion. Defect correction method. 2. The method of correcting a phase defect in a reflective photomask according to claim 1 , wherein the other of the two kinds of materials laminated on the phase defect portion is Mo (molybdenum). 2. The method of correcting a phase defect in a reflective photomask according to claim 1 , wherein the other of the two kinds of materials laminated on the phase defect portion is Ru (ruthenium). The multilayer film is laminated on the phase defect, said reflection type photomask as claimed in any one of claims 1 to 3, characterized in that it is laminated on peeling off the capping layer of the phase defect phase Defect correction method. The multilayer film laminated on the phase defect portion is laminated after peeling off a capping film of the phase defect portion and a part of the multilayer film under the capping film. 4. The phase defect correcting method for a reflective photomask according to any one of 3 above. The multilayer film stacked on the phase defect portion is formed by peeling a capping film of the phase defect portion, a multilayer film below the capping film, and further removing a defect below the multilayer film. Item 4. A method for correcting a phase defect in a reflective photomask according to any one of Items 1 to 3 .

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