JP6147514B2 - Method for manufacturing substrate for mask blank, method for manufacturing substrate with multilayer reflective film, method for manufacturing mask blank, and method for manufacturing transfer mask - Google Patents

Description

  The present invention relates to a method for producing a mask blank substrate, a method for producing a substrate with a multilayer reflective film using the substrate for mask blank, a method for producing a mask blank using the substrate for mask blank or the substrate with multilayer reflective film, and The present invention relates to a method for manufacturing a transfer mask using the mask blank.

  As mask blanks used in the 1x generation of semiconductor design rules (half pitch (hp) 14 nm, 10 nm, etc.), binary mask blanks and phase shift mask blanks for ArF excimer laser exposure, reflective mask blanks for EUV exposure, and nanoimprints There is a mask blank.

  In these mask blanks used in the 1x generation of semiconductor design rules, a defect of 30 nm class becomes a problem. For this reason, the main surface of the mask blank substrate used for the mask blank (that is, the surface on the side on which the transfer pattern is formed) has a defect of 30 nm class (SEVD of 18 nm or more and 34 nm or less) of 0 (zero). Or it is preferable to have as little as possible.

Patent Documents 1 and 2 describe a method for processing the surface of a mask blank substrate.
In Patent Literature 1, a defect is locally processed by bringing a frozen body obtained by freezing a polishing liquid containing an abrasive or a frozen body obtained by freezing ultrapure water into contact with and moving relative to the defect. To correct.
In Patent Document 2, a polishing substrate of a rotary small processing tool is brought into contact with the surface of a glass substrate with an abrasive interposed therebetween, and the surface of the glass substrate is scanned while rotating the polishing processing portion. Polish the surface to increase flatness.

Japanese Patent No. 4508779 JP 2010-194705 A

  However, in the processing method described in Patent Document 1, when a frozen body obtained by freezing a polishing liquid containing an abrasive is used, the abrasive remains on the mask blank substrate after processing. When the abrasive remains on the mask blank substrate, the abrasive acts as a mask at the time of cleaning after processing, and the mask blank substrate around the portion where the abrasive remains is etched. Thereby, a micro defect with a low height may occur in the mask blank substrate. By using an abrasive having an average particle size of 30 nm or less, it may be possible not to cause a defect of 30 nm class. However, in this case, the processing speed becomes slow, which is not practical. Further, since processing is performed using an abrasive, a defect such as a pit may be newly formed on the mask blank substrate. In addition, when a frozen body obtained by freezing ultrapure water is used, the frozen body is heavily consumed due to melting, and frequent replacement of the frozen body is required. In addition, since no abrasive is used, the processing speed is slow and not practical.

  In the processing method described in Patent Document 2, the abrasive remains on the mask blank substrate after processing. For this reason, as described above, a small defect having a low height may occur on the mask blank substrate. By using an abrasive having an average particle size of 30 nm or less, it may be possible not to cause a defect of 30 nm class. However, in this case, the processing speed becomes slow, which is not practical. Further, since processing is performed using an abrasive, a defect such as a pit may be newly formed on the mask blank substrate.

  For this reason, the present invention has been made in view of the above-described problems, and a practical mask blank substrate capable of reducing ultra-fine defects and undulations on the main surface that are problematic in the 1x generation of semiconductor design rules. Manufacturing method, manufacturing method of substrate with multilayer reflective film using this mask blank substrate, manufacturing method of mask blank using this mask blank substrate or substrate with multilayer reflective film, and for transfer using this mask blank An object is to provide a method for manufacturing a mask.

  In order to solve the above-described problems, the present invention has the following configuration.

(Configuration 1) A preparation process for preparing a mask blank substrate whose main surface is polished, and surface information including surface form information and position information on the main surface;
A specific part specifying step of detecting a specific part of the main surface exceeding a predetermined reference value from the surface form information, and specifying the position of the detected specific part by the position information;
A moving body having a catalyst surface disposed to face the main surface of the mask blank substrate is disposed at the position of the specific portion specified by the specific portion specifying step, and the catalyst surface, the specific portion, A local processing step of performing local processing by catalyst-based etching on the specific part in a state where a processing liquid is interposed between,
A method for manufacturing a mask blank substrate, comprising:

(Configuration 2) In the preparation step, the surface information is prepared by a surface information acquisition step of acquiring surface information including surface form information and position information on the main surface of the mask blank substrate whose main surface is polished. A method for manufacturing a mask blank substrate according to Configuration 1, wherein:

(Configuration 3) In the local processing step, the catalytic surface is brought into contact with or close to the specific portion, and the catalytic surface and the specific portion are moved relative to each other, whereby local processing by catalyst reference etching is performed on the specific portion. A method for manufacturing a mask blank substrate according to Configuration 1 or 2, wherein:

(Structure 4) The method for manufacturing a mask blank substrate according to any one of Structures 1 to 3, wherein the catalyst surface has an area smaller than the main surface of the mask blank substrate.

(Structure 5) The mask blank substrate according to any one of Structures 1 to 4, wherein the specific part is a defect composed of a convex part or a concave part, or a swell composed of a convex part and a concave part. Method.

(Configuration 6) When the specific part is a defect consisting of a convex part or a concave part,
The specific part specifying step further specifies the existence density of the defects on the main surface,
6. The method of manufacturing a mask blank substrate according to Configuration 5, wherein in the local processing step, local processing is preferentially performed on the specific portion in the region having a high existence density.

(Configuration 7) When the specific part is a defect composed of a convex part or a concave part,
The specific part specifying step further specifies the height of the convex part or the depth of the concave part,
6. The method of manufacturing a mask blank substrate according to Configuration 5, wherein the local processing step determines a processing allowance for the local processing based on the height or depth.

(Configuration 8) When the specific portion is a swell consisting of a convex portion and a concave portion,
6. The method of manufacturing a mask blank substrate according to Configuration 5, wherein the local processing step performs local processing on the convex portion.

(Configuration 9) The specific part specifying step further specifies the length of one wavelength of the swell, which is the total length of the width of the convex portion and the width of the concave portion,
9. The method for manufacturing a mask blank substrate according to Configuration 8, wherein the local processing step uses the moving body having the catalyst surface having a diameter smaller than the length of one wave of the undulation.

(Configuration 10) When the specific part is a swell consisting of a convex part and a concave part,
The specific part specifying step further specifies the height of the convex part and the depth of the concave part,
6. The method of manufacturing a mask blank substrate according to Configuration 5, wherein in the local processing step, a processing allowance for the local processing is determined based on a sum of the height and the depth.

(Arrangement 11) Any one of Arrangements 1 to 10, wherein the catalyst is made of at least one material selected from the group consisting of platinum, gold, transition metals, and alloys containing at least one of them. The manufacturing method of the mask blank board | substrate of description.

(Structure 12) The mask blank substrate manufacturing method according to any one of Structures 1 to 11, wherein the mask blank substrate is made of a glass material.

(Structure 13) The method for producing a mask blank substrate according to any one of Structures 1 to 12, wherein the treatment liquid is composed of a solvent that is not normally soluble in the mask blank substrate. .

(Structure 14) The method for manufacturing a mask blank substrate according to Structure 13, wherein the treatment liquid is pure water.

(Structure 15) A multilayer reflective film, wherein a multilayer reflective film is formed on a main surface of a mask blank substrate obtained by the method for producing a mask blank substrate according to any one of Structures 1 to 14. A method for manufacturing a substrate with a substrate.

(Configuration 16) On the main surface of the mask blank substrate obtained by the method for manufacturing a mask blank substrate according to any one of Configurations 1 to 14, or by the method for manufacturing a substrate with a multilayer reflective film according to Configuration 15 A mask blank manufacturing method, comprising: forming a transfer pattern thin film on a multilayer reflective film of the obtained multilayer reflective film-coated substrate.

(Structure 17) A transfer mask manufacturing method, wherein a transfer pattern is formed by patterning a transfer pattern thin film of a mask blank obtained by the mask blank manufacturing method described in Structure 16.

  As described above, according to the mask blank substrate manufacturing method of the present invention, the specific part of the main surface that exceeds a predetermined reference value is detected from the surface form information, and the specific part of the detected main surface is detected. The position is specified by the position information, the catalyst surface is arranged at the position of the specified specific part with the treatment liquid interposed, and the specific part is processed by catalyst reference etching. In processing by catalyst-based etching, the active species generated from the molecules in the processing liquid adsorbed on the catalyst surface react with the specific site to process the specific site. The active species are generated only on the catalyst surface, and deactivated when leaving the vicinity of the catalyst surface. For this reason, the specific site | part of the main surface which does not satisfy | fill a predetermined reference value can be processed locally. Further, since only a specific part of the main surface that does not satisfy the predetermined reference value is locally processed, the processing time can be shortened. Further, in the processing based on the catalyst-based etching, since no abrasive is used, damage to the mask blank substrate is extremely small, and generation of new defects can be prevented. Therefore, a mask blank substrate that satisfies a predetermined reference value can be manufactured in a short time.

  Further, according to the method for manufacturing a substrate with a multilayer reflective film according to the present invention, since the substrate with a multilayer reflective film is manufactured using the mask blank substrate obtained by the method for manufacturing a mask blank substrate described above, the substrate factor It is possible to prevent the generation of a part that does not satisfy the predetermined reference value, and to manufacture a substrate with a multilayer reflective film that satisfies the predetermined reference value.

  Moreover, according to the mask blank manufacturing method of the present invention, the multilayer reflective film obtained by the mask blank substrate obtained by the above-described mask blank substrate manufacturing method or the above-described multilayer reflective film-coated substrate manufacturing method. Since the mask blank is manufactured using the attached substrate, it is possible to prevent generation of a portion that does not satisfy the predetermined reference value due to the substrate factor, and it is possible to manufacture the mask blank that satisfies the predetermined reference value.

  In addition, according to the method for manufacturing a transfer mask according to the present invention, a transfer mask is manufactured using the mask blank obtained by the above-described mask blank manufacturing method. Therefore, a transfer mask that satisfies a predetermined reference value can be manufactured.

It is a fragmentary sectional view showing composition of a local catalyst standard etching processing device which performs local processing by catalyst standard etching to a mask blank substrate. It is a top view which shows the structure of the local catalyst reference | standard etching processing apparatus which performs the local process by a catalyst reference | standard etching with respect to the mask blank board | substrate. It is a photograph which shows the state of the convex defect before and behind local processing of the main surface of the mask blank substrate in Example 1 of the present invention. It is a photograph which shows the state of the concave defect before and behind local processing of the main surface of the mask blank substrate in Example 1 of the present invention. It is a figure which shows the defect inspection result before the local processing of the main surface of the board | substrate for mask blanks in Example 2 of this invention. It is a figure which shows the defect inspection result after the local process of the main surface of the board | substrate for mask blanks in Example 2 of this invention. It is a figure which shows the state of the wave | undulation before the local process of the main surface of the board | substrate for mask blanks in Example 3 of this invention. It is a figure which shows the state of the wave | undulation after the local process of the main surface of the board | substrate for mask blanks in Example 3 of this invention.

  Hereinafter, a method for manufacturing a mask blank substrate according to an embodiment of the present invention, a method for manufacturing a substrate with a multilayer reflective film using the mask blank substrate, and a mask using the mask blank substrate or the substrate with a multilayer reflective film A blank manufacturing method and a transfer mask manufacturing method using the mask blank will be described in detail.

Embodiment 1 FIG.
In the first embodiment, a method for manufacturing a mask blank substrate will be described.

In this Embodiment 1, the specific part which performs a local process in the preparatory process which prepares the mask blank board | substrate and the surface information with respect to the main surface of a mask blank board | substrate, and a local process process of a post process is detected, and the position is detected. A mask blank substrate is manufactured by a specific part specifying step to be specified and a local processing step of performing local processing by catalyst-based etching on the specific part.
Hereinafter, each process will be described in detail.

1. Preparation Step In the method for manufacturing a mask blank substrate, first, a preparation step of preparing a mask blank substrate whose main surface is polished and surface information for the main surface is performed. If necessary, surface information for the back surface opposite to the main surface of the mask blank substrate may be prepared. In that case, a preparation process, a surface information acquisition process, a specific part specifying process, and a local processing process performed on the main surface can be performed on the back surface.

In this preparation step, a mask blank substrate whose main surface is polished using the following processing method so as to have predetermined smoothness and flatness is prepared. However, it is not necessary to perform all the following processing methods, and it is performed by selecting appropriately so as to have predetermined smoothness and flatness.
As a processing method for reducing the surface roughness, for example, there are polishing and lapping using abrasive grains such as cerium oxide and colloidal silica.
As processing methods for improving the flatness, for example, magneto-rheological fluid polishing (Magneto Rheological Finishing: MRF), local chemical mechanical polishing (CMP), gas cluster ion beam etching (Gas Cluster Ion Beam etching): GCIB) and dry chemical planarization (DCP) using local plasma etching.
In the MRF, a magnetic polishing slurry obtained by mixing a polishing slurry in a magnetic fluid is brought into contact with a workpiece (mask blank substrate) at a high speed, and the dwell time at the contact portion is controlled to locally perform polishing. This is a local processing method.
CMP uses a polishing slurry containing abrasive grains such as a small diameter polishing pad and colloidal silica, and mainly controls the residence time of the contact portion between the small diameter polishing pad and the workpiece (mask blank substrate). This is a local processing method for polishing a convex portion on the surface of a workpiece.
GCIB generates gas cluster ions by ejecting a gaseous reactive substance (source gas) at room temperature and normal pressure while adiabatic expansion in a vacuum device, and ionizing it by electron irradiation. This is a local processing method in which ions are accelerated by a high electric field to form a gas cluster ion beam, which is irradiated to a workpiece to be etched.
DCP is a local processing method in which dry etching is locally performed by locally performing plasma etching and controlling the amount of plasma etching according to the degree of convexity.
In order to improve the surface roughness damaged by the above-described processing method for improving the flatness, as a processing method for improving the surface roughness while maintaining the flatness as much as possible, for example, float polishing, EEM (Elastic Emission Machining), hydroplane polishing.

  The prepared mask blank substrate may have already acquired surface information on the main surface or may not have acquired surface information on the main surface. If the surface information for the main surface has already been acquired, the acquired surface information is prepared. If the surface information for the main surface has not been acquired, the surface information is prepared by the surface information acquisition process for acquiring the surface information for the main surface.

  The surface information is the peripheral edge of the substrate when the mask blank substrate is 6025 size (152 mm × 152 mm × 6.35 mm) for the binary mask blank and phase shift mask blank used for ArF excimer laser exposure. Even if the mask blank substrate is 6025 size, it is acquired at least 132 mm × 132 mm area excluding the area and used for the reflective mask blank for EUV exposure, and at least the peripheral area of the substrate is excluded Acquired in an area of 132 mm × 132 mm.

The surface information includes surface form information and position information.
As the surface form information, information necessary for satisfying the surface quality (for example, flatness including defects and waviness) required for each generation in the semiconductor design rule is acquired and prepared. And the surface form information can be set as acquired information according to the detection sensitivity, measurement accuracy, etc. of the existing measurement apparatus and inspection apparatus. For example, the SEVD including a defect of 30 nm class can be information capable of detecting a swell caused by a defect of 23 nm or more and a striae of one wavelength of 1 to 20 mm. As information capable of detecting a defect whose SEVD including a defect of 30 nm class is 23 nm or more, for example, there is signal intensity information obtained when the main surface is scanned with a laser. Moreover, as information that can detect the undulation caused by the striae of one wavelength of 1 to 20 mm, for example, height information from a certain reference surface at a number of points (for example, 1024 × 1024 points) on the main surface. .
The position information may be information that can specify the position on the main surface of the mask blank substrate. For example, coordinate information based on a certain point.
If the surface morphology information is signal intensity information obtained when the main surface is scanned with a laser, and the position information is coordinate information at the point where the signal intensity information is obtained, the surface information is the main surface. On the other hand, it is a set of signal intensity information obtained when the laser is scanned and coordinate information at a point where the signal intensity information is obtained. In this case, the surface information can be stored in a computer or the like, and a location where the signal intensity exceeds a predetermined threshold can be output to a display device such as a monitor based on the surface information (see FIGS. 5 and 6). reference).
If the surface form information is height information at many points on the main surface and the position information is coordinate information at the many points, the surface information is the height information and coordinate information at many points on the main surface. Is a set. In this case, the surface information can be stored in a computer or the like, and the irregular shape of the main surface based on the surface information can be output to a display device such as a monitor (see FIGS. 7 and 8).

  The surface information acquisition process is performed using the following apparatus. By using this apparatus, surface information for the main surface of the mask blank substrate can be easily obtained.

Defect inspection apparatus (Teron600 series manufactured by KLA-Tencor, MAGICS M7360 manufactured by Lasertec). The defect inspection apparatus can detect convex defects (bumps, particles, etc.) composed of convex parts of 30 nm class, that is, SEVD of 23 nm or more, and concave defects (scratches, pits, etc.) composed of concave parts. Further, the defect inspection apparatus can distinguish between a convex defect and a concave defect, the size of the convex defect and the concave defect, and the position of the convex defect and the concave defect.
Atomic force microscope (AFM). The atomic force microscope can detect convex defects (bumps, particles, etc.) composed of convex parts of 30 nm class, that is, SEVD of 23 nm or more, and concave defects (scratches, pits, etc.) composed of concave parts. Further, the atomic force microscope can be used to distinguish between a convex defect and a concave defect, the type of the convex defect and the concave defect, the size of the convex defect and the concave defect, and the position of the convex defect and the concave defect.
Flatness measuring device (UltraFlat200 manufactured by Tropel). The flatness measuring device can detect the undulation caused by the striae having one wavelength of 1 to 20 mm.
Non-contact surface shape measuring device (Newview 6300 manufactured by Zygo). The non-contact surface shape measuring device can detect the undulation caused by the striae having one wavelength of 1 to 20 mm.

  When acquiring the surface information of the entire 132 mm × 132 mm area excluding the peripheral area of the 6025 size mask blank substrate, a defect inspection apparatus (KLA-Tencor Teron 600 series, Lasertec MAGICS M7360) and flatness A measuring device (UltraFlat 200 manufactured by Tropel) is preferable.

The material of the mask blank substrate is not particularly limited. For example, glass such as synthetic quartz glass, soda lime glass, borosilicate glass, aluminosilicate glass, SiO ₂ —TiO ₂ glass, or glass ceramics can be used. In addition, silicon or metal can also be used. However, the substrate material used for the transmissive mask blank needs to be a material having translucency with respect to the exposure wavelength to be used. For example, the substrate material used for the binary mask blank and the phase shift mask blank for ArF excimer laser exposure is preferably synthetic quartz glass. The substrate material used for the reflective mask blank needs to be a material having low thermal expansion. For example, the substrate material used for the reflective mask blank for EUV exposure is preferably SiO ₂ —TiO ₂ glass.

2. Specific part specifying step Next, a specific part on the main surface that exceeds a predetermined reference value is detected from the surface form information, and a specific part specifying step for specifying the position of the detected specific part based on the position information is performed.

The reference value to be satisfied by the main surface of the mask blank substrate is, for example, as follows, taking into account the surface quality required by the 1x generation of semiconductor design rules and the detection sensitivity and detection accuracy of existing measurement and inspection devices can do.
(1) Defect reference value In the case of a mask blank substrate used for a reflective mask blank for EUV exposure, the number of defects having a SEVD of 23 nm or more in a 132 mm × 132 mm region excluding the peripheral region of a 6025 size substrate 30 or less.
The defect is a convex defect composed of convex parts such as bumps and particles, or a concave defect composed of concave parts such as scratches and pits. SEVD is the length of the diameter when the defect is assumed to be hemispherical.
(2) Reference value of waviness caused by striae In the case of a mask blank substrate used for a reflective mask blank for EUV exposure, at least 132 mm × 132 mm area excluding the peripheral area of the 6025 size substrate The sum (hereinafter referred to as PV value) of the maximum height of the convex portion and the maximum depth of the concave portion with respect to the reference surface of the undulation caused by the striae having a wavelength of 1 to 20 mm is 5 nm or less.
Note that the undulation caused by striae is repeated so that the convex part and the concave part wave. One wavelength of undulation caused by striae is the total length of the width of the convex portion and the width of the concave portion in the pair of convex portions and concave portions.

In the local processing step to be described later, when local processing is performed by catalyst-based etching so as to satisfy the above-described defect reference value (that is, when a specific portion is a defect), in this specific portion specifying step, first, for mask blank From the surface morphology information of the substrate, a defect whose SEVD including a defect of 30 nm class is 23 nm or more is detected. Then, the density of defects is specified. In order to satisfy the defect reference value, it is determined which defect should be corrected (removed). At that time, a defect in a region having a relatively high density of defects is preferentially determined as a defect to be corrected (removed). Thereafter, the position of the defect to be corrected (removed) is specified from the position information of the mask blank substrate.
For example, when the surface information is a set of signal intensity information obtained when the main surface is scanned with a laser and coordinate information at a point where the signal intensity information is obtained, based on the surface information, A portion where the signal intensity exceeds a threshold value that is recognized as a defect of 23 nm or more is displayed on a display device such as a monitor (see FIGS. 5 and 6). Then, the density of defects is determined with reference to the display on the monitor or the like. In order to satisfy the defect reference value, it is determined which defect should be corrected (removed). At that time, a defect in a region having a relatively high density of defects is preferentially determined as a defect to be corrected (removed). Thereafter, the position of the defect to be corrected (removed) is specified from the position information of the mask blank substrate.
The density of defects can be determined not only by referring to a display on a monitor or the like, but also by dividing the main surface into a plurality of regions and counting the number of defects in each region.

Further, in the local processing step described later, when performing local processing by catalyst-based etching so as to satisfy the reference value of waviness due to the above-described striae (that is, when the specific part is waviness due to striae), In this specific part specifying step, first, undulation caused by striae having a wavelength of 1 to 20 mm with a PV value larger than 5 nm is detected from the surface form information of the mask blank substrate. Then, the position of the convex part of the waviness is specified from the position information of the mask blank substrate.
For example, when the surface information is a set of height information and coordinate information at a number of points on the main surface, the uneven shape of the main surface based on the surface information is displayed on a display device such as a monitor (FIG. 7, 8). Then, with reference to a display on a monitor or the like, a swell of one wavelength of 1 to 20 mm with a PV value larger than 5 nm is detected. Then, the position of the convex part of the waviness is specified from the position information of the mask blank substrate.

  In this specific part specifying step, when the specific part is a defect, the height of the convex defect or the depth of the concave defect may be specified. In this case, first, a defect whose SEVD including a defect of 30 nm class is 23 nm or more is detected from the surface shape information of the mask blank substrate. In order to satisfy the defect reference value, it is determined which defect should be corrected (removed). Thereafter, the position of the defect to be corrected (removed) is specified from the position information of the mask blank substrate, and the height of the convex defect or the depth of the concave defect to be corrected (removed) is specified from the surface form information of the mask blank substrate. .

  In addition, when the specific part is undulation caused by striae, the length of one wave of undulation may be further specified. In this case, first, undulation caused by striae having a wavelength of 1 to 20 mm with a PV value larger than 5 nm is detected from the surface form information of the mask blank substrate. Thereafter, the position of the convex portion of the undulation is specified from the position information of the mask blank substrate, and the length of one wavelength of the undulation is specified from the surface form information and the position information of the mask blank substrate.

  In addition, when the specific part is undulation caused by striae, the sum of the height of the convex part of the swell relative to the reference plane and the depth of the concave part may be specified. In this case, first, undulation caused by striae having a wavelength of 1 to 20 mm with a PV value larger than 5 nm is detected from the surface form information of the mask blank substrate. After that, the position of the convex portion of the undulation is specified from the position information of the mask blank substrate, and the sum of the height of the convex portion of the undulation and the depth of the concave portion with respect to the reference plane is specified from the surface form information of the mask blank substrate. .

3. Next, a moving body having a catalyst surface disposed to face the main surface of the mask blank substrate is disposed at the position of the specific portion specified by the specific portion specifying step, and the catalyst surface and the specific portion are arranged. In a state where the treatment liquid is interposed between the two, a local processing step is performed in which a specific processing is performed on the specific part by catalyst-based etching (CARE).

  In this local processing step, first, the position of the specific part specified by the specific part specifying step described above in a state where the moving body having the catalyst surface is arranged facing the main surface of the mask blank substrate. To place. Then, the treatment liquid is supplied between the catalyst surface and the specific part, and the catalyst surface of the moving body is brought into contact with or close to the specific part with the treatment liquid interposed between the catalyst surface and the specific part. The catalyst surface and the specific part are moved relative to each other while applying a predetermined load (processing pressure) to the mask blank substrate. If the catalyst surface and the specific part are moved relative to each other with the treatment liquid interposed between the catalyst surface and the specific part, the active species generated from the molecules in the treatment liquid adsorbed on the catalyst surface are specified. The site reacts and the specific site is processed. The active species are generated only on the catalyst surface and deactivated when separated from the vicinity of the catalyst surface. Therefore, the reaction with the active species hardly occurs except for a specific portion where the catalyst surface comes into contact or approaches. In this way, local processing is performed on the specific part by catalyst-based etching. When there are a plurality of specific portions, local processing is similarly performed on all the specific portions by catalyst-based etching. Thereby, the specific part is corrected (removed), and a mask blank substrate that satisfies the reference value can be obtained.

When the specific part is a defect, local processing is preferentially performed on a defect in a region having a relatively high density of defects. Thereby, defects can be efficiently corrected (removed).
When the specific part is waviness caused by striae, local processing is applied to the convex portion of the waviness. Thereby, the undulation resulting from striae can be efficiently corrected (removed).

  The relative motion between the catalyst surface and the specific part is not particularly limited as long as the catalyst surface and the specific part are relatively moved. When the mask blank substrate is fixed and the moving body is moved, the moving body is fixed and the mask blank substrate is moved, or both the moving body and the mask blank substrate are moved. When the moving body moves, the movement is caused by rotating around the axis perpendicular to the main surface of the mask blank substrate or when reciprocating in a direction parallel to the main surface of the mask blank substrate. is there. Similarly, when the mask blank substrate moves, the movement of the mask blank substrate reciprocates in the direction parallel to the main surface of the mask blank substrate or the case of rotating around an axis perpendicular to the main surface of the mask blank substrate. For example, when exercising.

  The load (working pressure) applied to the mask blank substrate is, for example, 1 to 200 hPa.

  The catalyst that forms the catalyst surface is not particularly limited as long as it can generate active species. For example, platinum, gold, transition metals (for example, molybdenum, iron, silver, copper) that promote the reaction of oxidizing hydrogen and extracting hydrogen ions and atoms, and alloys containing at least one of these (for example, At least one material selected from the group consisting of stainless steel (SUS) can be used. A ceramic solid catalyst can also be used.

The treatment liquid is not particularly limited as long as it is a solvent that does not normally exhibit solubility with respect to the mask blank substrate. By using such a processing liquid, the mask blank substrate is not dissolved by the processing liquid, and unnecessary deformation of the mask blank substrate can be prevented. For example, pure water, ozone water, carbonated water, or hydrogen water can be used. Further, when the mask blank substrate is not normally dissolved by the treatment liquid in which the halogen-containing molecules are dissolved, a treatment liquid in which the halogen-containing molecules are dissolved can be used. Here, as the molecule containing halogen, hydrogen halide is preferable, but a molecule having a bond such as C—F, SF, NF, C—Cl, S—Cl, or N—Cl may be used. it can. Halogen includes fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), but the chemical reaction actually decreases as the atomic number increases, so it is actually used as a treatment liquid. It is possible to use hydrofluoric acid (HF aqueous solution). However, hydrofluoric acid (HF aqueous solution) dissolves the SiO ₂ component in the glass, and hydrochloric acid (HCl aqueous solution) selectively dissolves Ti contained in the SiO ₂ —TiO ₂ glass having low thermal expansion. It will be eluted. In consideration of these factors and processing time, it is preferable to use hydrohalic acid adjusted to an appropriate concentration.

  When the mask blank substrate is made of a glass material, local processing by catalyst-based etching can be performed by using platinum as a catalyst and pure water as a treatment liquid. It is considered that the hydrolysis reaction proceeds by using platinum as a catalyst and pure water as a treatment liquid. For this reason, when the mask blank substrate is made of a glass material, it is preferable to use platinum as the catalyst and pure water as the treatment liquid from the viewpoint of cost and processing characteristics.

The moving body includes a catalyst platen on which a catalyst surface is formed. The material of the portion of the catalyst platen on which the catalyst surface is formed is not particularly limited. For example, rubber, light transmissive resin, foamable resin, and non-woven fabric can be used. The catalyst surface is formed by coating the catalyst on the surface of the catalyst platen facing the main surface of the mask blank substrate.
The overall shape of the catalyst platen is not particularly limited. For example, the outer shape of a disk, a sphere, a cylinder, a cone, or a pyramid can be used. The surface shape of the portion of the catalyst platen on which the catalyst surface is formed is not particularly limited. For example, a flat, hemispherical, or rounded shape can be used.

The catalyst surface formed on the catalyst surface plate has an area smaller than the area for acquiring the surface information of the main surface of the mask blank substrate. Thereby, it becomes easy to process a specific part locally. In addition, it is possible to suppress bending and sag that may occur in the case of a large catalyst surface. For example, area of the catalyst surface, if a particular site is ^defective, a 1mm ² ~1000mm 2, if a particular site is swell due to striae, for ^example, a 1mm ² ~30mm 2.

  When the specific part is undulation caused by striae, the length of one wave of undulation is specified in the specific part specifying step described above, and a moving body having a catalyst surface having a diameter smaller than the length of one wave of undulation is used. It is preferable. Thereby, it becomes easy to process locally the undulation resulting from striae. Here, the diameter means a portion where the length of the catalyst surface is maximum. For example, the diameter is a diameter when the catalyst surface is circular, and a diagonal line when the catalyst surface is rectangular.

The machining allowance in local processing by catalyst-based etching is, for example, 0.5 nm to 50 nm.
If the specific part is a defect, the height of the convex defect or the depth of the concave defect is specified in the above-mentioned specific part specifying step, and the processing in the local processing is performed based on the height of the convex defect or the depth of the concave defect. It is preferable to determine the cost. Thereby, a convex defect or a concave defect can be reliably corrected (removed).
If the specific part is a swell due to striae, the height of the convex part of the swell relative to the reference surface and the depth of the concave part are specified in the specific part specifying step described above, and the height of the convex part of the swell relative to the reference surface is determined. It is preferable to determine the machining allowance in local machining based on the sum of the depth of the recess and the recess. Thereby, the undulation resulting from striae can be reliably corrected (removed).

  FIG. 1 and FIG. 2 show an example of a local catalyst reference etching processing apparatus that performs local processing by catalyst reference etching on a mask blank substrate. FIG. 1 is a partial cross-sectional view of a local catalyst-based etching processing apparatus, and FIG. 2 is a plan view of the local catalyst-based etching processing apparatus.

  The local catalyst-based etching processing apparatus 1 is disposed in a cylindrical chamber 2, a substrate support unit 3 that is disposed in the chamber 2 and supports the mask blank substrate M, and is opposed to the mask blank substrate M. The moving body 4, the moving body moving means 5 that moves the moving body 4 to a predetermined position, and the processing liquid supply means 6 that supplies the processing liquid onto the main surface M 1 of the mask blank substrate M are provided.

The chamber 2 is provided with an opening 21 formed in the center of the bottom 23 of the chamber 2 and the processing liquid supplied from the processing liquid supply means 6 in order to arrange a shaft portion 33 of the substrate support means 3 to be described later in the chamber 2. In order to discharge the liquid, the bottom 23 of the chamber 2 is provided with a discharge port 22 formed closer to the outer periphery than the opening 21. In FIG. 1, the state in which the processing liquid is discharged from the discharge port 22 is indicated by arrows.
The substrate support means 3 includes a support portion 31 that supports the mask blank substrate M, a flat portion 32 that fixes the support portion 31, and a shaft that supports the flat portion 32 and extends to the outside of the chamber 2 through the opening 21. Part 33. The support part 31 has a rectangular shape when the local catalyst reference etching processing apparatus 1 is viewed from above, and includes a housing part 31a that supports four sides of the periphery of the back surface M2 of the mask blank substrate M. The flat portion 32 has a circular shape when the local catalyst reference etching processing apparatus 1 is viewed from above. The shaft portion 33 extends in a direction perpendicular to the main surface M1 of the mask blank substrate M placed on the support portion 31 and is placed on the support portion 31 by driving means (not shown). It can be rotated about an axis perpendicular to the main surface M1 of the substrate M for rotation (see arrow A in FIG. 1). The center of the flat surface portion 32 and the center of the mask blank substrate M placed on the support portion 31 are positioned in the extending direction of the rotation center of the shaft portion 33. By rotating the shaft portion 33, the plane portion 32 supported by the shaft portion 33 rotates around the center thereof, and the mask blank placed on the support portion 31 fixed to the plane portion 32. The substrate M rotates with its center as the center of rotation.
The moving body 4 includes a catalyst surface plate 41 and a catalyst surface plate mounting portion 42 to which the catalyst surface plate 41 is attached. The catalyst surface plate 41 is formed by coating on the entire surface of the surface plate body, the covering member formed on the entire surface of the surface plate body so as to cover the surface plate body, and the covering member on the side facing the mask blank substrate. And a catalytic surface. The catalyst platen mounting portion 42 measures an air cylinder 42a that applies a load to the catalyst platen 41 and a load applied to the catalyst platen 41 by the air cylinder 42a, and turns on an air valve so that the predetermined load is not exceeded. A load cell 42b that controls the load applied to the catalyst surface plate 41 by the air cylinder 42a is provided. When performing local processing by catalyst-based etching, a load (processing pressure) applied to the catalyst surface plate 41 by the air cylinder 42a is applied to the mask blank substrate M. The moving body 4 has an axis perpendicular to the main surface M1 of the mask blank substrate M placed on the support portion 31 by driving means (not shown) provided on an arm portion 51 of the moving body moving means 5 described later. (See arrow B in FIGS. 1 and 2).

  The moving body moving means 5 is connected to the upper end of the moving body 4 and extends to the periphery of the chamber 2 and extends in a direction parallel to the main surface M1 of the mask blank substrate M placed on the support section 31; A shaft portion 52 that supports the end portion of the arm portion 51 extending to the periphery of the chamber 2 and extends in a direction perpendicular to the main surface M1 of the mask blank substrate M placed on the support portion 31, and a lower end of the shaft portion 52 The base part 53 to support is provided, and the guide 54 which is arrange | positioned around the chamber 2 and defines the movement path | route of the base part 53 is provided. The arm portion 51 can move in the longitudinal direction (see a double arrow C in FIGS. 1 and 2). The shaft part 52 can move the arm part 51 up and down by moving in the longitudinal direction (see a double-headed arrow D in FIG. 1). The base 53 can turn the arm 51 by rotating a predetermined angle about an axis perpendicular to the main surface M1 of the mask blank substrate M placed on the support 31. (See double arrow E in FIGS. 1 and 2). The guide 54 is disposed in a direction (first direction and second direction) parallel to two adjacent sides of the mask blank substrate M placed on the support portion 31, and an L-shaped moving path of the base portion 53. Form. The base portion 53 moves along the guide 54 in the first direction, thereby moving the arm portion 51 in the first direction (see the double arrow F in FIG. 2), and the guide 54 in the second direction. The arm portion 51 can be moved in the second direction by moving along (see the double arrow G in FIG. 2). By such movement of the arm portion 51, the catalyst surface plate 41 can be disposed at a predetermined position on the main surface M1 of the mask blank substrate M placed on the support portion 31.

  The treatment liquid supply means 6 is disposed in a treatment liquid supply hole (not shown) formed in the center of the catalyst surface plate 41 and the catalyst surface plate mounting portion 42 and supplies a treatment liquid to the treatment liquid supply hole. A liquid supply nozzle 61 and a pipe (not shown) that is disposed in the arm portion 51 and supplies the processing liquid to the processing liquid supply nozzle 61 are provided. The processing liquid is supplied to the processing liquid supply nozzle 61 in the catalyst surface plate mounting portion 42 through a pipe in the arm portion 51, and from the processing liquid supply hole formed in the center of the catalyst surface plate 41, the mask blank substrate M. On the main surface M1. The method for supplying the processing liquid is not limited to this, and the processing liquid may be supplied by providing a processing liquid supply nozzle that supplies the processing liquid to the outside of the moving body 4.

  As a control method for securing the machining allowance as set, for example, various local processing conditions (processing pressure, rotational speed (catalyst surface plate), processing liquid for mask blank substrate M separately prepared in advance) Flow rate), machining time and machining allowance are determined, local machining conditions and machining time as desired machining allowance are determined, and the machining allowance is controlled by controlling the machining time. be able to. The method is not limited to this, and various methods may be selected as long as the machining allowance can be ensured as set.

When performing local processing by catalyst-based etching using the local catalyst-based etching processing apparatus shown in FIGS. 1 and 2, first, the mask blank substrate M is mounted on the support portion 31 with the main surface M1 facing upward. Place and fix.
Thereafter, the arm part 51 moves in the longitudinal direction (double arrow C), the arm part 51 pivots (double arrow E), the arm part 51 moves in the first direction (double arrow F), and the arm part 51 moves in the second direction ( With the double arrow G), the catalyst surface plate 41 is placed at the position of the specific part specified by the specific part specifying step in a state where the catalyst surface of the catalyst surface plate 41 is arranged facing the main surface M1 of the mask blank substrate M. Place.
Thereafter, while rotating the moving body 4 at a predetermined rotational speed, the processing liquid is supplied onto the main surface M1 of the mask blank substrate M from the processing liquid supply hole formed at the center of the catalyst surface plate 41, and the mask blank is used. A treatment liquid is interposed between the main surface M1 of the substrate M and the catalyst surface. In this state, the catalyst surface of the catalyst surface plate 41 is brought into contact with or close to the main surface M1 of the mask blank substrate M by the vertical movement of the arm portion 51 (double arrow D). At that time, the load applied to the catalyst surface plate 41 is controlled to a predetermined value, and a predetermined load (processing pressure) is applied to the mask blank substrate M.
Thereafter, when the predetermined machining allowance is reached, the rotation of the moving body 4 and the supply of the processing liquid are stopped. Then, the catalyst surface plate 41 is separated from the main surface M1 of the mask blank substrate M by a predetermined distance by the vertical movement of the arm portion 51 (double arrow D).
Thereafter, the catalyst surface plate 41 is arranged at the position of the other specific part specified by the specific part specifying step, and the same processing is performed.
The mask blank substrate M is removed from the support portion 31 after performing local processing by catalyst-based etching on all the specific portions detected by the specific portion specifying step.

  The mask blank substrate M is manufactured through such a preparation process, a specific part specifying process, and a local processing process.

  According to the mask blank substrate manufacturing method of the first embodiment, the specific part of the main surface M1 exceeding the predetermined reference value is detected from the surface form information, and the position of the detected specific part of the main surface M1 is detected. Is specified by the position information, the catalyst surface is arranged at the position of the specified specific part with the treatment liquid interposed, and the specific part is processed by catalyst reference etching. In processing by catalyst-based etching, the active species generated from the molecules in the processing liquid adsorbed on the catalyst surface react with the specific site to process the specific site. The active species are generated only on the catalyst surface, and deactivated when leaving the vicinity of the catalyst surface. For this reason, the specific site | part of the main surface M1 which does not satisfy | fill a predetermined reference value can be processed locally, SEVD including a 30 nm class defect is 23 nm or more, and one wavelength 1-20 nm whose PV value is larger than 5 nm It is possible to locally correct (remove) the undulation caused by the striae. Further, since only a specific part of the main surface M1 that does not satisfy the predetermined reference value is locally processed, the processing time can be shortened. Further, in the processing based on the catalyst-based etching, since no abrasive is used, damage to the mask blank substrate M is extremely small, and generation of new defects can be prevented. Therefore, a mask blank substrate that satisfies a predetermined reference value can be manufactured in a short time.

  Further, according to the mask blank substrate manufacturing method of the first embodiment, when the specific portion is a defect, the mask blank substrate M having a high-quality main surface with reduced microscopic defects is manufactured. In the case where the specific portion is waviness due to striae, a mask blank substrate M having a main surface with high flatness in which waviness due to striae is reduced to the limit can be manufactured.

  In addition, in the mask blank substrate manufacturing method according to the first embodiment, not only the defect correction (removal) and the swell correction (removal) due to striae are performed alone, but also the striae first. It is also possible to correct (remove) the undulation caused by the defect and then correct (remove) the defect.

  Further, in the manufacturing method of the mask blank substrate of the first embodiment, the defect is corrected (removed) and striae with respect to the mask blank substrate M whose main surface M1 is polished by using the catalyst reference etching. The swell to be corrected (removed) may be performed.

The mask blank substrate M manufactured by the method described in the mask blank substrate manufacturing method of the first embodiment can be used for manufacturing a binary mask blank, a phase shift mask blank, and a nanoimprint mask blank. . Binary mask blank is, MoSi-based, Ta system, may be any of the Cr-based. The phase shift mask blank may be any of a halftone type phase shift mask blank, a Levenson type phase shift mask blank, and a chromeless type phase shift mask blank.

Embodiment 2. FIG.
In Embodiment 2, a method for manufacturing a substrate with a multilayer reflective film will be described.

In the second embodiment, high refractive index layers and low refractive index layers are alternately formed on the main surface M1 of the mask blank substrate M manufactured by the method described in the mask blank substrate manufacturing method of the first embodiment. A multilayer reflective film laminated on is formed to produce a substrate with a multilayer reflective film, or a protective film is formed on the multilayer reflective film to produce a substrate with a multilayer reflective film.
About the multilayer reflective film surface or protective film surface of the produced multilayer reflective film-coated substrate, surface information is obtained in the same manner as the mask blank substrate. The surface information includes surface form information and position information. The surface information is acquired using the following apparatus. By using this apparatus, surface information on the surface of the multilayer reflective film and the surface of the protective film of the substrate with the multilayer reflective film can be easily obtained.
Defect inspection apparatus (Teron600 series manufactured by KLA-Tencor, MAGICS M7360 manufactured by Lasertec). The defect inspection apparatus can detect convex defects (particles, bumps, etc.) composed of convex parts of 30 nm class, that is, SEVD of 23 nm or more, and concave defects (pits, etc.) composed of concave parts. Further, the defect inspection apparatus can distinguish between a convex defect and a concave defect, the size of the convex defect and the concave defect, and the position of the convex defect and the concave defect.
The reference value of the defect to be satisfied by the surface of the multilayer reflective film or the protective film surface of the substrate with the multilayer reflective film is, for example, as follows.
In a 132 mm × 132 mm area excluding the peripheral area of a 6025 size substrate, the SEVD is 30 nm or less and the number of defects is 30 or less.
Next, the surface information is compared with a reference value for defects on the surface of the multilayer reflective film or the surface of the protective film. When the reference value is satisfied, a reflective mask blank described in Embodiment 3 described later is manufactured. When the reference value is not satisfied, the defective portion is repaired by a known defect repairing method, or the multilayer reflective film and the protective film are peeled off, and the preparation process of the first embodiment is performed.

  According to the method for manufacturing a substrate with a multilayer reflective film according to the second embodiment, a substrate with a multilayer reflective film is manufactured using the mask blank substrate M obtained by the method for manufacturing a mask blank substrate according to the first embodiment. Therefore, it is possible to prevent generation of a part that does not satisfy the predetermined reference value due to the substrate factor, and it is possible to manufacture a substrate with a multilayer reflective film that satisfies the predetermined reference value.

  In addition, the board | substrate with a multilayer reflective film manufactured by the method demonstrated by the manufacturing method of the board | substrate with a multilayer reflective film of this Embodiment 2 can be used for manufacture of a reflective mask blank.

Embodiment 3 FIG.
In Embodiment 3, a mask blank manufacturing method will be described.

  In this third embodiment, an absorber film as a transfer pattern thin film is formed on the protective film of the multilayer reflective film-coated substrate manufactured by the method described for the multilayer reflective film-coated substrate of the second embodiment, Alternatively, a protective film and an absorber film as a transfer pattern thin film are formed on the multilayer reflective film of the substrate with the multilayer reflective film, and a back conductive film is formed on the back surface on which the multilayer reflective film is not formed. A blank is manufactured.

  In the third embodiment, a light-shielding film as a transfer pattern thin film is formed on the main surface M1 of the mask blank substrate M manufactured by the method described in the mask blank substrate manufacturing method of the first embodiment. To produce a binary photomask blank, or to form a halftone film as a transfer pattern thin film to produce a halftone phase shift mask blank, or to form a halftone film and a light shielding film in turn as a transfer pattern thin film Thus, a halftone phase shift mask blank is manufactured. These binary photomask blanks and halftone phase shift mask blanks are transmissive mask blanks.

About the produced mask blank, you may acquire surface information similarly to the board | substrate for mask blanks. The surface information includes surface form information and position information. The surface information is acquired using the following apparatus. By using this apparatus, surface information for the mask blank surface can be easily obtained.
Defect inspection apparatus (Teron600 series manufactured by KLA-Tencor, MAGICS M7360 manufactured by Lasertec). The defect inspection apparatus can detect convex defects (particles, bumps, etc.) consisting of convex parts of 30 nm class, that is, SEVD of 23 nm or more, and concave defects (pinholes, half pinholes, pits, etc.) consisting of concave parts. . Further, the defect inspection apparatus can distinguish between a convex defect and a concave defect, the size of the convex defect and the concave defect, and the position of the convex defect and the concave defect.
The reference value to be satisfied by the mask blank surface can be set as appropriate.

  According to the third embodiment, the multilayer reflection obtained by the mask blank substrate M obtained by the mask blank substrate production method of the first embodiment or the multilayer reflection film-coated substrate production method of the second embodiment. Since the mask blank is manufactured using the substrate with the film, it is possible to prevent generation of a portion that does not satisfy the predetermined reference value due to the substrate factor, and it is possible to manufacture the mask blank that satisfies the predetermined reference value.

Embodiment 4 FIG.
In the fourth embodiment, a method for manufacturing a transfer mask will be described.

  In the fourth embodiment, a resist pattern is obtained by performing exposure / development processing on a transfer pattern thin film of a reflective mask blank or a transmissive mask blank manufactured by the method described in the mask blank manufacturing method of the third embodiment. Form. Using this resist pattern as a mask, the transfer pattern thin film is etched to form a transfer pattern to manufacture a transfer mask.

  According to the fourth embodiment, since the transfer mask is manufactured using the mask blank obtained by the mask blank manufacturing method of the third embodiment, it is possible to prevent the occurrence of transfer pattern defects in the transfer target. And a transfer mask satisfying a predetermined reference value can be manufactured.

Hereinafter, based on an Example, this invention is demonstrated more concretely.

Example 1.
A. Manufacture of glass substrate for mask blank Substrate preparation process First, the following rough polishing process, precision polishing process, and ultraprecision polishing process were performed on a TiO ₂ —SiO ₂ glass substrate having a size of 6025 (152 mm × 152 mm × 6.35 mm).

(1) Rough Polishing Process Step 10 glass substrates that have undergone end chamfering and grinding were set in a double-side polishing apparatus, and rough polishing was performed under the following polishing conditions. A set of 10 sheets was performed 5 times, and a total of 50 glass substrates were roughly polished. The processing load and polishing time were adjusted as appropriate.
Polishing slurry: Aqueous solution containing cerium oxide (average particle size 2 to 3 μm) Polishing pad: Hard polisher (urethane pad)
After the rough polishing, in order to remove the abrasive grains adhering to the glass substrate, the glass substrate was immersed in a cleaning tank and cleaned by applying ultrasonic waves.

(2) Precision polishing process step Ten glass substrates after rough polishing were set in a double-side polishing apparatus, and precision polishing was performed under the following polishing conditions. A set of 10 sheets was performed 5 times, and a total of 50 glass substrates were precisely polished. The processing load and polishing time were adjusted as appropriate.
Polishing slurry: Aqueous solution containing cerium oxide (average particle size 1 μm) Polishing pad: Soft polisher (suede type)
After the precision polishing, in order to remove abrasive grains adhering to the glass substrate, the glass substrate was immersed in a cleaning tank and cleaned by applying ultrasonic waves.

(3) Ultra-precision polishing process Step 10 glass substrates that had been subjected to precision polishing were again set in a double-side polishing apparatus, and ultra-precision polishing was performed under the following polishing conditions. A 10-sheet set was performed 5 times, and a total of 50 glass substrates were subjected to ultra-precision polishing. The processing load and polishing time were adjusted as appropriate.
Polishing slurry: alkaline aqueous solution (pH 10.2) containing colloidal silica
(Colloidal silica content 50wt%)
Polishing pad: Super soft polisher (suede type)
After ultra-precision polishing, the glass substrate was immersed in a cleaning tank containing an alkali cleaning solution of sodium hydroxide and cleaned by applying ultrasonic waves.

2. Surface information acquisition process Next, the surface information acquisition process which acquires the surface information with respect to the main surface of the glass substrate after a rough polishing process process, a precision polishing process process, and an ultra-precision polishing process process was performed.

  This surface information acquisition process was performed by defect-inspecting the main surface of a glass substrate using a defect inspection apparatus (Teron600 series made by KLA-Tencor). The defect inspection was performed on a 132 mm × 132 mm region excluding the peripheral region of the main surface of the glass substrate.

3. Specific part specifying step Next, a specific part specifying step for specifying the position of a defect to be locally processed in the subsequent local processing step was performed on the glass substrate after the surface information acquisition step. In addition, about the defect which performs a local process, the defect state was measured with the atomic force microscope (AFM).

  This specific part specifying process refers to the defect inspection result, and corrects which defect to satisfy the above-described defect standard value (for a region of 132 mm × 132 mm, SEVD is 30 nm or more with a defect number of 30 nm or less). It was determined by determining (removal) and specifying the position of the defect to be corrected (removed).

4). Next, using the local catalyst reference etching processing apparatus shown in FIG. 1 and FIG. 2, local processing by catalyst reference etching is performed for the defect decided to be corrected (removed) in the specific part specifying step. The applied local processing step was performed.

In this embodiment, a disk-shaped surface plate body made of stainless steel (SUS) having a diameter of 35 mm, and fluoro rubber (Viton (registered trademark)) formed on the entire surface of the surface plate body so as to cover the surface plate body, A catalyst surface plate 41 composed of a catalyst surface formed by coating on the entire surface of the fluororubber on the side facing the mask blank substrate was used.
The processing conditions are as follows.
Catalyst: Platinum Treatment liquid: Pure water Number of rotations of substrate support means 3 (number of rotations of glass substrate): 0 rotation / minute Number of rotations of moving body 4 (number of rotations of catalyst surface plate 41): 10 rotations / minute Processing pressure: 150 hPa
Processing allowance: 10nm

First, the glass substrate was placed and fixed on the support portion 31 with the main surface facing upward.
Thereafter, the longitudinal movement of the arm 51 (double arrow C), the swing movement of the arm 51 (double arrow E), the first movement of the arm 51 (double arrow F), and the second movement of the arm 51 ( With the double arrow G), the catalyst platen 41 was arranged at the position of the defect identified in the specific part identifying step with the catalyst surface of the catalyst platen 41 facing the main surface of the glass substrate.
After that, without rotating the glass substrate, the catalyst surface plate 41 is rotated at a rotation speed of 10 rotations / minute, and from the processing liquid supply hole formed in the center of the catalyst surface plate 41, the pure surface is formed on the main surface of the glass substrate. Water was supplied, and pure water was interposed between the main surface of the glass substrate and the catalyst surface. In that state, the catalyst surface of the catalyst surface plate 41 was brought into contact with or brought close to the main surface of the glass substrate by the vertical movement of the arm portion 51 (double arrow D). At that time, the load applied to the catalyst surface plate 41 was controlled to 150 hPa, and a processing pressure of 150 hPa was applied to the glass substrate.
Thereafter, when the machining allowance reached 10 nm, the rotation of the catalyst platen 41 and the supply of pure water were stopped. Then, the catalyst surface plate 41 was separated from the main surface of the glass substrate by a predetermined distance by the vertical movement of the arm portion 51 (double arrow D).
After all the defects decided to be corrected (removed) in the specific part specifying step were subjected to local processing by catalyst-based etching, the glass substrate was removed from the support portion.

Thereafter, the end surface of the glass substrate removed from the support portion 31 was scrubbed.
Thereafter, the glass substrate was immersed in a washing tank containing aqua regia (temperature of about 65 ° C.) for about 10 minutes.
Thereafter, rinsing with pure water and drying were performed.
In this way, a mask blank substrate was produced.

B. Verification of reduction effect of 30 nm class defects (defects with SEV of 23 nm or more) by local processing process FIGS. 3 and 4 show the defects before and after local processing of the main surface of the mask blank substrate measured by an atomic force microscope (AFM). Indicates the state. FIG. 3 shows the state of convex defects, and FIG. 4 shows the state of concave defects.

FIG. 3A shows a convex defect having a SEVD of 26 nm before local processing. FIG. 3B shows a state after local processing of this convex defect. As shown in FIG. 3B, the convex defect having a SEVD of 26 nm disappeared by local processing by the catalyst-based etching.
FIG. 3C shows a convex defect having a SEVD of 33 nm before local processing. FIG. 3D shows the state of the convex defect after local processing. As shown in FIG. 3D, the convex defect having an SEVD of 33 nm disappeared by local processing by the catalyst-based etching.
FIG. 3E shows a convex defect having a SEVD of 50 nm before local processing. FIG. 3F shows a state after local processing of this convex defect. As shown in FIG. 3 (F), the convex defect having a SEVD of 50 nm disappeared by local processing by the catalyst-based etching.
FIG. 4A shows a concave defect with a SEVD of 34 nm before local processing. FIG. 4B shows a state after local processing of this concave defect. As shown in FIG. 4B, a concave defect with a SEVD of 34 nm was corrected to a size of SEVD of 25 nm by local processing by catalyst-based etching.
FIG. 4C shows a concave defect with a SEVD of 28 nm before local processing. FIG. 4D shows a state after local processing of the concave defect. As shown in FIG. 4 (D), the concave defect with an SEVD of 28 nm was corrected to a size of SEVD of 21 nm by local processing by catalyst-based etching.
FIG. 4E shows a concave defect having a SEVD of 40 nm before local processing. FIG. 4F shows a state after local processing of the concave defect. As shown in FIG. 4 (F), the concave defect having a SEVD of 40 nm was corrected to a size of 25 nm of SEVD by local processing by catalyst-based etching.
As the above-mentioned result shows, the number of defects and the size of SEVDs including defects of 30 nm class having 23 nm or more can be reduced by local processing by catalyst-based etching.

Example 2
A. Manufacture of glass substrate for mask blank Substrate preparation process First, a rough polishing process, a precision polishing process, and an ultra-precision polishing process were performed on a 6025 size TiO ₂ —SiO ₂ glass substrate in the same manner as in Example 1.

Then, the flatness of the main surface and the back surface of the glass substrate after the rough polishing process, the precision polishing process, and the ultraprecision polishing process was measured using a flatness measuring apparatus (UltraFlat 200 manufactured by Tropel). The flatness measurement was performed on an area of 148 mm × 148 mm excluding the peripheral area of the glass substrate. As a result, the flatness of the main surface and the back surface was 290 nm (convex shape).
Moreover, the measurement result of the flatness of the main surface of a glass substrate and a back surface is preserve | saved in a computer as height information with respect to a virtual absolute plane for every measurement point, and the reference value 40nm of the flatness of the main surface required for a glass substrate ( (Concave shape) and a reference value of the flatness of the back surface of 70 nm (concave shape), and the difference was calculated by a computer for each predetermined region of the main surface and the back surface of the glass substrate. This difference becomes a necessary removal amount (processing allowance) of each predetermined region in local surface processing described later.
Then, the processing conditions of the local surface processing according to required removal amount were set for every predetermined area | region of the main surface and back surface of a glass substrate. The setting method is as follows. Using a dummy substrate in advance, the dummy substrate is processed at a certain point (spot) without moving the substrate for a certain period of time in the same manner as in actual processing, and the shape thereof is measured with a flatness measuring device (UltraFlat 200 manufactured by Tropel). Measurement was performed, and the processing volume at the spot per unit time was calculated. Then, the scanning speed for raster scanning of the glass substrate was determined according to the processing volume at the spot per unit time and the necessary removal amount of each predetermined area calculated as described above.
Thereafter, the flatness of the main surface and the back surface of the glass substrate is set to be equal to or less than the above-described reference value by using a substrate finishing apparatus (manufactured by QED Technologies) by magnetic viscoelastic fluid polishing (Magneto Rheological Finishing: MRF). The surface was locally processed according to the processing conditions set for each predetermined region. The magnetic polishing slurry used at this time is a mixture of a magnetic fluid containing iron and a polishing slurry composed of an aqueous alkaline solution and cerium oxide (about 2 wt%) as an abrasive.
Thereafter, the glass substrate was immersed in a cleaning tank containing an aqueous hydrochloric acid solution having a concentration of about 10% (temperature: about 25 ° C.) for about 10 minutes.
Thereafter, rinsing with pure water and drying with isopropyl alcohol (IPA) were performed.
Thereafter, touch polishing was performed on both the main surface and the back surface of the glass substrate using colloidal silica abrasive grains.
Thereafter, the glass substrate was immersed in an alkali cleaning solution of sodium hydroxide and cleaned by applying ultrasonic waves.

2. Surface information acquisition process Next, the surface information acquisition process which acquires the surface information with respect to the main surface of the glass substrate after a substrate preparation process was performed.
The surface information acquisition step was performed by inspecting the main surface of the glass substrate for defects using a defect inspection apparatus (Teron600 series manufactured by KLA-Tencor). The defect inspection was performed on a 132 mm × 132 mm region excluding the peripheral region of the main surface of the glass substrate.

FIG. 5 shows a defect inspection result before local processing measured by the defect inspection apparatus. FIG. 5 shows a defect having a SEVD of 23 nm or more, which is determined based on the surface information acquired by the defect inspection apparatus.
As a result of the defect inspection, in the 132 mm × 132 mm region excluding the peripheral region of the main surface of the glass substrate, the total number of defects having a SEVD of 23 nm or more was 49. Incidentally, the number of 30 nm class defects having SEVD of 23 nm or more and 34 nm or less was 44.

3. Specific part specifying step Next, a specific part specifying step for specifying the position of a defect to be locally processed in the subsequent local processing step was performed on the glass substrate after the surface information acquisition step.

  This specific part specifying process refers to the defect inspection result, and corrects which defect to satisfy the above-described defect standard value (for a region of 132 mm × 132 mm, SEVD is 30 nm or more with a defect number of 30 nm or less). It was determined by determining (removal) and specifying the position of the defect to be corrected (removed). In the second embodiment, with reference to the defect inspection result shown in FIG. 5, it is decided to correct (remove) defects in a plurality of areas having a relatively high defect density, and the positions of the defects in those areas are determined. Identified. For example, it was decided to correct (remove) the defects in the areas S and T in FIG.

4). Local processing step Local processing was performed under the same conditions as in Example 1. First, the catalyst surface plate 41 is arranged at the defect position in the first region (for example, S in FIG. 5) decided to be corrected (removed), the defect is corrected (removed), and then 2 The catalyst surface plate 41 was placed at the defect position in the first region (for example, T in FIG. 5), and the same processing was performed.
After performing local processing by catalyst-based etching on defects in all regions decided to be corrected (removed) in the specific part specifying step, the glass substrate was taken out from the support portion.
Thereafter, the end surface of the glass substrate removed from the support portion 31 was scrubbed.
Thereafter, the glass substrate was immersed in a washing tank containing aqua regia (temperature of about 65 ° C.) for about 10 minutes.
Thereafter, rinsing with pure water and drying were performed.
In this way, a mask blank substrate was produced.

5). Evaluation It is preferable that the main surface of a mask blank substrate used for manufacturing a reflective mask blank for EUV exposure used in the semiconductor design rule 1x generation has the following smoothness and flatness.
Smoothness: Root mean square roughness (RMS) with a surface roughness of 0.15 nm or less, preferably 0.10 nm or less, more preferably 0.08 nm or less.
Flatness: When the glass substrate is 6025 size, the flatness is 30 nm or less for a 132 mm × 132 mm region excluding the peripheral region of the substrate.

Surface roughness and flatness were measured with respect to the main surface of the glass substrate after the local processing step. Also, defect inspection was performed.
The surface roughness was measured with an atomic force microscope (AFM) for a 1 μm × 1 μm region at the center of the substrate. As a result, the surface roughness was as good as 0.06 nm in terms of root mean square roughness (RMS).
The flatness was measured with respect to a 132 mm × 132 mm area excluding the peripheral area of the substrate with a flatness measuring device (UltraFlat 200 manufactured by Tropel). As a result, the flatness was as good as 29 nm.
The defect inspection was performed on a 132 mm × 132 mm area excluding the peripheral area of the glass substrate with a defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor). FIG. 6 shows a defect inspection result after local processing acquired by the defect inspection apparatus. FIG. 6 shows a defect whose SEVD is 23 nm or more. As a result of the defect inspection, in the 132 mm × 132 mm area excluding the peripheral area of the glass substrate, the total number of defects having a SEVD of 23 nm or more was 8. Incidentally, the number of 30 nm class defects having SEVD of 23 nm or more and 34 nm or less was five. Due to local processing by catalyst-based etching, the number of defects with SEVD of 23 nm or more is reduced from 49 to 8, and the number of 30 nm class defects with SEVD of 23 to 34 nm is also reduced from 44 to 5. A glass substrate satisfying the standard value was obtained.

B. Next, a high refractive index layer (film thickness: 4.2 nm) made of a silicon film (Si) and a molybdenum film are formed on the main surface of the glass substrate after the local processing step by an ion beam sputtering method. A pair of high-refractive index layers and low-refractive index layers are alternately stacked with (Mo) low-refractive index layers (2.8 nm), and 40 pairs are stacked to form a multilayer reflective film (film thickness 280 nm). did.
Thereafter, a protective film (thickness 2.5 nm) made of ruthenium (Ru) was formed on the multilayer reflective film by ion beam sputtering.

In this way, a substrate with a multilayer reflective film was produced.
The obtained substrate with a multilayer reflective film was subjected to a defect inspection on the surface of the protective film using a defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor). The defect inspection was performed on a 132 mm × 132 mm region. As a result, the number of defects with SEVD of 23 nm or more was 19, and the number of defects of 30 nm with SEVD of 23 nm or more and 34 nm or less was 12. Thus, a substrate with a multilayer reflective film satisfying the above-mentioned reference value was obtained.

C. Production of Reflective Mask Blank Next, an absorber film (film) made of a tantalum boron nitride film (TaBN) is formed on the protective film of the substrate with the multilayer reflective film thus produced by reactive sputtering (DC sputtering). A thickness of 70 nm) was formed. The sputtering conditions are as follows. Reactive sputtering (DC sputtering) was performed in a mixed gas atmosphere of xenon (Xe) and nitrogen (N ₂ ) with a tantalum boride (TaB) target facing the protective film of the substrate with a multilayer reflective film.

Then, the back surface conductive film (film thickness 20nm) which consists of chromium nitride films (CrN) was formed by reactive sputtering (DC sputtering) on the back surface which has not formed the multilayer reflection film of the board | substrate with a multilayer reflection film. The sputtering conditions are as follows. Reactive sputtering (DC sputtering) was performed in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ) with a chromium (Cr) target facing the back surface of the multilayer reflective film-coated substrate.

  In this way, a reflective mask blank for EUV exposure was produced.

D. Manufacture of the reflective mask Next, the thus prepared was reflective mask on blank, a chemically amplified positive resist for electron beam writing (exposure) was applied by spin coating, through the heating and cooling steps, A resist film having a thickness of 150 nm was formed.
Thereafter, a desired pattern was drawn on the formed resist film using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern.
Thereafter, using this resist pattern as a mask, the absorber film was dry-etched to form an absorber film pattern on the protective film. As a dry etching gas, Cl ₂ gas was used.
Thereafter, the resist pattern was removed and cleaning was performed.

  In this manner, a reflective mask for EUV exposure was produced.

Example 3 FIG.
A. Manufacture of mask blank glass substrate
1. Substrate Preparation Step First, a substrate preparation step was performed in the same manner as in Example 2 on a 6025 size TiO ₂ —SiO ₂ glass substrate.

2. Surface information acquisition process Next, the surface information acquisition process which acquires the surface information with respect to the main surface of the glass substrate after a substrate preparation process was performed.
This surface information acquisition process was performed using the flatness measuring apparatus (UltraFlat200 by Tropel). The measurement by the flatness measuring device was performed on a 132 mm × 132 mm region excluding the peripheral region of the main surface of the glass substrate.
FIG. 7 shows the state of undulation caused by striae before local processing, measured by the flatness measuring device. FIG. 7 shows the uneven shape of the main surface of the glass substrate based on the surface information acquired by the flatness measuring device. In FIG. 7, only the undulation resulting from the striae in the range of 1 wavelength to 1 mm is extracted and shown. 7A shows a plan view of the concavo-convex shape of the entire main surface of the glass substrate, and FIG. 7B is a cross-section of the concavo-convex shape of the main surface at a position from point A to point B in FIG. The figure is shown. In FIG. 7B, the horizontal axis indicates the distance from the point A, and the vertical axis indicates the height based on the lowest point between A and B. The bar on the right side in FIG. 7A shows a gradation of +30 nm height and −30 nm height when the position of the broken line in FIG. 7B is 0. The position of this broken line is the position of the virtual absolute plane (reference plane). In addition, the height of the convex part of a wave | undulation resulting from striae and the depth of a concave part are represented by the distance from this virtual absolute plane (reference plane).
As shown in FIG. 7, in a 132 mm × 132 mm area excluding the peripheral area of the main surface of the glass substrate, the swell PV value due to striae was 22 nm.
Moreover, while acquiring surface information using the flatness measuring apparatus (UltraFlat200 by Tropel), the flatness was measured with respect to the main surface of the glass substrate after a board | substrate preparation process. As a result, the flatness was 42 nm.

3. Specific part specifying step Next, a specific part specifying step for specifying the position of the undulation caused by the striae that performs the local processing in the subsequent local processing step was performed on the glass substrate after the surface information acquisition step.

  This specific part specifying step was performed by referring to the uneven shape shown in FIG. 7 and detecting a plurality of undulations caused by striae with PV values larger than 5 nm and specifying the positions of the convex portions of those undulations. . For example, the undulations of U and V in FIG. 7B are detected, and the positions of the convex portions of those undulations are specified.

4). Local processing step Next, a local processing step of applying local processing by catalyst-based etching to a plurality of undulations detected in the specific part specifying step using the local catalyst-based etching processing apparatus shown in FIGS. 1 and 2 is performed. went.

  In this example, a catalyst surface plate having the same configuration as that of Example 1 was used except that the diameter of the disk-shaped surface plate body was 5 mm. The processing conditions are the same as in Example 1.

First, the glass substrate was placed and fixed on the support portion 31 with the main surface facing upward.
Thereafter, the longitudinal movement of the arm 51 (double arrow C), the swing movement of the arm 51 (double arrow E), the first movement of the arm 51 (double arrow F), and the second movement of the arm 51 ( By the double-headed arrow G), undulation (for example, due to the first striae specified by the specific part specifying step in a state where the catalyst surface of the catalyst platen 41 is arranged to face the main surface of the glass substrate (for example, The catalyst surface plate 41 was arranged at the position of the convex part of U) in FIG.
After that, without rotating the glass substrate, the catalyst surface plate 41 is rotated at a rotation speed of 10 rotations / minute, and from the processing liquid supply hole formed in the center of the catalyst surface plate 41, the pure surface is formed on the main surface of the glass substrate. Water was supplied, and pure water was interposed between the main surface of the glass substrate and the catalyst surface. In that state, the catalyst surface of the catalyst surface plate 41 was brought into contact with or brought close to the main surface of the glass substrate by the vertical movement of the arm portion 51 (double arrow D). At that time, the load applied to the catalyst surface plate 41 was controlled to 150 hPa, and a processing pressure of 150 hPa was applied to the glass substrate.
Thereafter, the catalyst surface plate 41 was scanned along the position of the undulation convex portion. When the machining allowance reached 5 nm, the rotation of the catalyst surface plate 41 and the supply of pure water were stopped. Then, the catalyst surface plate 41 was separated from the main surface of the glass substrate by a predetermined distance by the vertical movement of the arm portion 51 (double arrow D).
After that, the catalyst surface plate 41 is arranged at the position of the undulation (for example, V in FIG. 7B) specified by the specific part specifying step due to the second striae, and the same processing is performed. Went.
After the local processing by the catalyst-based etching was performed on the undulating convex portions caused by all the striae specified in the specific site specifying step, the glass substrate was removed from the support portion 31.

Thereafter, the end surface of the glass substrate removed from the support portion 31 was scrubbed.
Thereafter, the glass substrate was immersed in a washing tank containing aqua regia (temperature of about 65 ° C.) for about 10 minutes.
Thereafter, rinsing with pure water and drying were performed.

5). Evaluation Concave and convex shapes were measured on the main surface of the glass substrate after the local processing step using a flatness measuring device (UltraFlat 200 manufactured by Tropel).
FIG. 8 shows the state of undulation caused by striae after local processing measured by the flatness measuring device. FIG. 8 shows the uneven shape of the main surface of the glass substrate based on the surface information acquired by the flatness measuring device. In FIG. 8, only the undulation caused by the striae in the range of one wavelength of 1 to 20 mm is extracted and shown. 8A shows a plan view of the concavo-convex shape of the entire main surface of the glass substrate, and FIG. 8B is a cross-section of the concavo-convex shape of the main surface at a position from point C to point D in FIG. The figure is shown. In FIG. 8B, the horizontal axis indicates the distance from the point C, and the vertical axis indicates the height based on the lowest point between CD. The bar on the right side in FIG. 8A shows a gradation of +30 nm height and −30 nm height when the position of the broken line in FIG. 8B is 0. The position of this broken line is the position of the virtual absolute plane (reference plane).
As shown in FIG. 8, in a 132 mm × 132 mm region excluding the peripheral region on the main surface of the glass substrate, the PV value of undulation caused by striae was as good as 5 nm. By the local processing by the catalyst standard etching, the PV value was reduced from 22 nm to 5 nm, and a glass substrate satisfying the standard value of the swell due to the above-mentioned striae was obtained.
Moreover, while using the flatness measuring apparatus (UltraFlat200 by Tropel), the uneven | corrugated shape was measured and the flatness was measured with respect to the main surface of the glass substrate after a local processing process. As a result, the flatness was good at 27 nm. Flatness was improved from 42 nm to 27 nm by local processing by catalyst-based etching with waviness correction.

《Defect correction》
1. Substrate preparation process The above-described "waviness correction" corresponds to the substrate preparation process in defect correction.

2. Surface information acquisition process, specific part specifying process, local processing process Next, the surface information acquisition process, specific part specifying process, and local processing process were performed on the glass substrate after undulation correction, as in Example 1. .
The surface information acquisition step was performed by inspecting the main surface of the glass substrate for defects using a defect inspection apparatus (Teron600 series manufactured by KLA-Tencor). The defect inspection was performed on a 132 mm × 132 mm area excluding the peripheral area of the glass substrate.
As a result of the defect inspection, in the 132 mm × 132 mm region excluding the peripheral region of the main surface of the glass substrate, the total number of defects having an SEVD of 23 nm or more was 38. Incidentally, the number of 30 nm class defects having SEVD of 23 nm or more and 34 nm or less was 34.

3. Evaluation Surface roughness and flatness were measured on the main surface of the glass substrate after the local processing step. Also, defect inspection was performed.

The surface roughness was measured with an atomic force microscope (AFM) for a 1 μm × 1 μm region at the center of the substrate. As a result, the surface roughness was as good as 0.06 nm in terms of root mean square roughness (RMS).
The flatness was measured with respect to a 132 mm × 132 mm area excluding the peripheral area of the substrate with a flatness measuring device (UltraFlat 200 manufactured by Tropel). As a result, the flatness was good at 27 nm. The flatness was not deteriorated by local processing by catalyst-based etching for defect correction.
The defect inspection was performed on a 132 mm × 132 mm area excluding the peripheral area of the glass substrate with a defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor). As a result of the defect inspection, in the 132 mm × 132 mm area excluding the peripheral area of the glass substrate, the total number of defects with SEVD of 23 nm or more is reduced to 7, and the number of defects of 30 nm class with SEVD of 23 nm to 34 nm is also 4 The piece was good.

B. Production of substrate with multilayer reflective film Next, a multilayer reflective film and a protective film were formed on the main surface of the glass substrate after the local processing step in the same manner as in Example 2 to produce a substrate with multilayer reflective film.

  The obtained substrate with a multilayer reflective film was subjected to a defect inspection on the surface of the protective film using a defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor). The defect inspection was performed on a 132 mm × 132 mm region. As a result, the number of defects with a SEVD of 23 nm or more was 17 and the number of defects of 30 nm with a SEVD of 23 nm to 34 nm was 11 to obtain a substrate with a multilayer reflective film satisfying the above-mentioned reference value.

C. Production of Reflective Mask Blank Next, an absorber film is formed on the protective film of the substrate with the multilayer reflective film thus produced, as in Example 2, and then the multilayer of the substrate with the multilayer reflective film is formed. A back surface conductive film was formed on the back surface on which no reflective film was formed in the same manner as in Example 2 to produce a reflective mask blank for EUV exposure.

D. Manufacture of the reflective mask Next, the thus prepared was reflective mask on blank, in the same manner as in Example 2, to form an absorber pattern was produced a reflective mask for EUV exposure.

Comparative Example 1
A mask blank substrate and a multilayer reflective film-coated substrate were produced in the same manner as in Example 2 except that the steps after the surface information acquisition step were not performed.

Surface roughness and flatness were measured with respect to the main surface of the obtained glass substrate. Also, defect inspection was performed.
The surface roughness was measured with an atomic force microscope (AFM) for a 1 μm × 1 μm region at the center of the substrate. As a result, the surface roughness was almost the same as in Example 2.
The flatness was measured with respect to a 132 mm × 132 mm area excluding the peripheral area of the substrate with a flatness measuring device (UltraFlat 200 manufactured by Tropel). As a result, the flatness was almost the same as in Example 2.
The defect inspection was performed on a 132 mm × 132 mm area excluding the peripheral area of the glass substrate with a defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor). As a result of the defect inspection, the total number of defects having a SEVD of 23 nm or more in a region of 132 mm × 132 mm excluding the peripheral region of the glass substrate was 63. The number of 30 nm-class defects having SEVD of 23 nm or more and 34 nm or less was 52, and did not satisfy the above-described defect reference value.

  Further, as in Example 2, a multilayer reflective film and a protective film were formed on the main surface of the glass substrate by ion beam sputtering to produce a substrate with a multilayer reflective film.

  The obtained substrate with a multilayer reflective film was subjected to a defect inspection on the surface of the protective film using a defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor). The defect inspection was performed on a 132 mm × 132 mm region. As a result, the number of defects with SEVD of 23 nm or more was 87, and the number of defects of 30 nm with SEVD of 23 nm or more and 34 nm or less was 55, which did not satisfy the above-mentioned reference value.

  In the above-described embodiments, the mask blank substrate, the substrate with the multilayer reflective film, the reflective mask blank, and the reflective mask used for the reflective mask blank for EUV exposure have been described as examples. However, the present invention is not limited thereto. . The present invention can also be applied to a mask blank substrate and a transmission mask blank used for a transmission mask blank (binary mask blank, phase shift mask blank, etc.) for ArF excimer laser exposure. According to these applications, the reference value of the surface of the mask blank substrate and the transmissive mask blank can be determined.

DESCRIPTION OF SYMBOLS 1 Local catalyst reference | standard etching processing apparatus, 2 Chamber, 3 Substrate support means, 4 Moving body, 5 Moving body moving means, 6 Process liquid supply means, 21 Opening part, 22 Discharge port, 23 Bottom part, 31 Support part, 31a accommodation Part, 32 plane part, 33 shaft part, 41 catalyst surface plate, 42 catalyst surface plate mounting part, 42a air cylinder, 42b load cell, 51 arm part, 52 shaft part, 53 base part, 54 guide, 61 processing liquid supply nozzle, M Mask blank substrate, M1 main surface, M2 back surface.

Claims (20)

A preparatory step of preparing a mask blank substrate having a polished main surface, and surface information including surface form information and position information with respect to the main surface;
A specific part specifying step of detecting a specific part of the main surface exceeding a predetermined reference value from the surface form information, and specifying the position of the detected specific part by the position information;
A moving body having a catalyst surface disposed to face the main surface of the mask blank substrate is disposed at the position of the specific portion specified by the specific portion specifying step, and the catalyst surface, the specific portion, A local processing step of performing local processing by catalyst-based etching on the specific part in a state where a processing liquid is interposed between,
I have a,
The method of manufacturing a mask blank substrate, wherein the treatment liquid is pure water, ozone water, carbonated water, or hydrogen water . The hood is defective form of the convex portion or concave portion or the process of claim 1 Symbol placement of the mask blank substrate, characterized in that a swell consisting protrusions and recesses. When the specific part is a defect consisting of a convex part or a concave part,
The specific part specifying step further specifies the existence density of the defects on the main surface,
3. The method of manufacturing a mask blank substrate according to claim 2 , wherein in the local processing step, local processing is preferentially performed on the specific part of the region having a high existence density. When the specific part is a defect consisting of a convex part or a concave part,
The specific part specifying step further specifies the height of the convex part or the depth of the concave part,
3. The method for manufacturing a mask blank substrate according to claim 2 , wherein in the local processing step, a processing allowance for the local processing is determined based on the height or depth. When the specific part is a swell consisting of a convex part and a concave part,
3. The method for manufacturing a mask blank substrate according to claim 2 , wherein the local processing step performs local processing on the convex portion. The specific part specifying step further specifies the length of one wavelength of the undulation, which is the total length of the width of the convex portion and the width of the concave portion,
6. The method for manufacturing a mask blank substrate according to claim 5 , wherein the local processing step uses the moving body having the catalyst surface having a diameter smaller than the length of one wavelength of the undulation. When the specific part is a swell consisting of a convex part and a concave part,
The specific part specifying step further specifies the height of the convex part and the depth of the concave part,
3. The method of manufacturing a mask blank substrate according to claim 2 , wherein in the local processing step, a processing allowance for the local processing is determined based on a sum of the height and the depth.   A preparatory step of preparing a mask blank substrate having a polished main surface, and surface information including surface form information and position information with respect to the main surface;
  A specific part specifying step of detecting a specific part of the main surface exceeding a predetermined reference value from the surface form information, and specifying the position of the detected specific part by the position information;
  A moving body having a catalyst surface disposed to face the main surface of the mask blank substrate is disposed at the position of the specific portion specified by the specific portion specifying step, and the catalyst surface, the specific portion, A local processing step of performing local processing by catalyst-based etching on the specific part in a state where a processing liquid is interposed between,
  Have
  The specific part is a defect consisting of a convex part or a concave part, or a swell consisting of a convex part and a concave part,
  When the specific part is a defect consisting of a convex part or a concave part,
    The specific part specifying step further specifies the existence density of the defects on the main surface,
    In the local processing step, the mask blank substrate manufacturing method is characterized in that local processing is preferentially performed on the specific portion in the region having a high existence density.   A preparatory step of preparing a mask blank substrate having a polished main surface, and surface information including surface form information and position information with respect to the main surface;
  A specific part specifying step of detecting a specific part of the main surface exceeding a predetermined reference value from the surface form information, and specifying the position of the detected specific part by the position information;
  A moving body having a catalyst surface disposed to face the main surface of the mask blank substrate is disposed at the position of the specific portion specified by the specific portion specifying step, and the catalyst surface, the specific portion, A local processing step of performing local processing by catalyst-based etching on the specific part in a state where a processing liquid is interposed between,
  Have
  The specific part is a defect consisting of a convex part or a concave part, or a swell consisting of a convex part and a concave part,
  When the specific part is a defect consisting of a convex part or a concave part,
    The specific part specifying step further specifies the height of the convex part or the depth of the concave part,
    The method for manufacturing a mask blank substrate, wherein the local processing step determines a processing allowance for the local processing based on the height or depth.   A preparatory step of preparing a mask blank substrate having a polished main surface, and surface information including surface form information and position information with respect to the main surface;
  A specific part specifying step of detecting a specific part of the main surface exceeding a predetermined reference value from the surface form information, and specifying the position of the detected specific part by the position information;
  A moving body having a catalyst surface disposed to face the main surface of the mask blank substrate is disposed at the position of the specific portion specified by the specific portion specifying step, and the catalyst surface, the specific portion, A local processing step of performing local processing by catalyst-based etching on the specific part in a state where a processing liquid is interposed between,
  Have
  The specific part is a defect consisting of a convex part or a concave part, or a swell consisting of a convex part and a concave part,
  When the specific part is a swell consisting of a convex part and a concave part,
    The method for manufacturing a mask blank substrate, wherein the local processing step performs local processing on the convex portion.   The specific part specifying step further specifies the length of one wavelength of the undulation, which is the total length of the width of the convex portion and the width of the concave portion,
  The method for manufacturing a mask blank substrate according to claim 10, wherein the local processing step uses the moving body having the catalyst surface having a diameter smaller than the length of one wavelength of the undulation.   A preparatory step of preparing a mask blank substrate having a polished main surface, and surface information including surface form information and position information with respect to the main surface;
  A specific part specifying step of detecting a specific part of the main surface exceeding a predetermined reference value from the surface form information, and specifying the position of the detected specific part by the position information;
  A moving body having a catalyst surface disposed to face the main surface of the mask blank substrate is disposed at the position of the specific portion specified by the specific portion specifying step, and the catalyst surface, the specific portion, A local processing step of performing local processing by catalyst-based etching on the specific part in a state where a processing liquid is interposed between,
  Have
  The specific part is a defect consisting of a convex part or a concave part, or a swell consisting of a convex part and a concave part,
  When the specific part is a swell consisting of a convex part and a concave part,
    The specific part specifying step further specifies the height of the convex part and the depth of the concave part,
    The method for manufacturing a mask blank substrate, wherein the local processing step determines a processing allowance for the local processing based on a sum of the height and the depth. The preparation step is characterized in that the surface information is prepared by a surface information acquisition step of acquiring surface information including surface form information and position information with respect to the main surface of the mask blank substrate whose main surface is polished. The manufacturing method of the mask blank substrate as described in any one of Claims 1 thru | or 12 . In the local processing step, the catalytic surface is brought into contact with or close to the specific portion, and the catalytic surface and the specific portion are moved relative to each other, thereby subjecting the specific portion to local processing by catalyst reference etching. 14. The method for manufacturing a mask blank substrate according to claim 1 , wherein the mask blank substrate is a mask blank substrate. The catalyst surface, method of manufacturing a substrate for a mask blank according to any one of claims 1 to 14, characterized in that it has a smaller area than said main surface of the substrate for the mask blank. The catalyst of platinum, gold, according to any one of claims 1 to 15, characterized in that it consists of at least one material selected from the group consisting of an alloy containing at least one of the transition metals and their A method for manufacturing a mask blank substrate. The method for manufacturing a mask blank substrate according to any one of claims 1 to 16 , wherein the mask blank substrate is made of a glass material. To claim 1 or on the main surface of the substrate for a mask blank obtained by any method for producing a substrate for a mask blank according to one of the 17, the multilayer reflective film coated substrate, which comprises forming a multilayer reflective film Production method. It is obtained by the manufacturing method of the board | substrate with a multilayer reflective film of Claim 18 on the main surface of the mask blank board | substrate obtained by the manufacturing method of the mask blank board | substrate as described in any one of Claims 1 thru | or 17. A method for producing a mask blank, comprising: forming a transfer pattern thin film on a multilayer reflective film of the substrate with the multilayer reflective film. A method for manufacturing a transfer mask, comprising: patterning a transfer pattern thin film of a mask blank obtained by the mask blank manufacturing method according to claim 19 to form a transfer pattern.

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