WO2010092937A1 - Substrate for mask blank use, mask blank, and photo mask - Google Patents

Substrate for mask blank use, mask blank, and photo mask Download PDF

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Publication number
WO2010092937A1
WO2010092937A1 PCT/JP2010/051842 JP2010051842W WO2010092937A1 WO 2010092937 A1 WO2010092937 A1 WO 2010092937A1 JP 2010051842 W JP2010051842 W JP 2010051842W WO 2010092937 A1 WO2010092937 A1 WO 2010092937A1
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WO
WIPO (PCT)
Prior art keywords
substrate
mask blank
region
blank substrate
main surface
Prior art date
Application number
PCT/JP2010/051842
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French (fr)
Japanese (ja)
Inventor
丸山　修
原田　和明
赤川　裕之
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Hoya株式会社
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Application filed by Hoya株式会社 filed Critical Hoya株式会社
Priority to JP2010525128A priority Critical patent/JP4839411B2/en
Priority to KR1020117018452A priority patent/KR101168712B1/en
Priority to CN2010800075296A priority patent/CN102317860B/en
Publication of WO2010092937A1 publication Critical patent/WO2010092937A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
    • B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
    • B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
    • B24B9/065—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of thin, brittle parts, e.g. semiconductors, wafers
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/38—Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/60—Substrates

Definitions

  • the present invention relates to a mask blank substrate, and more particularly to a large mask blank substrate for manufacturing an FPD device.
  • Recent electronic devices are required to be further miniaturized with the rapid development of IT technology.
  • One of the technologies that support such a fine processing technology is a lithography technology using a photomask called a transfer mask.
  • a fine pattern is formed on a silicon wafer by exposing an electromagnetic wave or light wave of an exposure light source to a silicon wafer with a resist film through a photomask.
  • This photomask is usually manufactured by forming a thin film pattern to be a transfer pattern by patterning the thin film using a lithography technique on a mask blank in which a thin film such as a light-shielding film is formed on a translucent substrate.
  • the main surface of the substrate is mirror-polished, and the end surface formed on the periphery of the main surface of the substrate is also polished to have a predetermined mirror surface.
  • FPD Flat Panel Display
  • the end face there is no requirement for the end face to be a mirror surface at the beginning of development, and the end face remains rough. Met.
  • FIG. 4 is a perspective view showing a large mask blank substrate.
  • the large mask blank substrate 10 has two main surfaces 11 and four end surfaces T.
  • the end surface T of the large mask blank substrate 10 it is conceivable to make the end surface T of the large mask blank substrate 10 a mirror surface.
  • the large mask blank substrate 10 was manually held so as to sandwich the end face T. In this case, when the end surface T is handled, there is a problem that the large mask blank substrate 10 cannot be held due to slipping between the handling gloves and the large mask blank substrate 10.
  • the end surface should have a surface roughness that does not slip when a person grips the substrate while the substrate is wet.
  • the surface roughness of the end surface Ra is set to about 0.05 to 0.4 ⁇ m (Japanese Patent Laid-Open No. 2005-37580 (Patent Document 1)), or the surface roughness Ra of the end face is set to 0.03 to 0.3 ⁇ m, for example (Japanese Patent Laid-Open No. 2005-37580).
  • Patent Document 2 Japanese Patent Laid-Open No. 2005-37580
  • Patent Documents 1 and 2 When the conventional entire end face is subjected to rough polishing (no mirror polishing) or when the surface roughness Ra of the end face T is set to about 0.03 to 0.4 ⁇ m (Patent Documents 1 and 2), The generation of glass chips from the end surface during substrate polishing has been increasing, which has been a problem.
  • the present invention has been made to solve the above-described problems, and it is possible to suppress the generation of particles such as glass chips and abrasive residues from the end face during polishing, and the rate of occurrence of surface defects associated therewith.
  • An object of the present invention is to provide a mask blank substrate.
  • FIGS. 5A to 5C are diagrams for explaining the generation of glass chips
  • FIG. 5A is a top view showing a state of polishing the main surface (right rotation of the main surface)
  • FIG. 5B is a view of polishing the main surface
  • FIG. 5C is a side view of the end surface and the carrier during polishing of the main surface.
  • the substrate 10 is held by the substrate holding portion 31a of the carrier 31, and the carrier 31 rotates coaxially with the center of the rotating substrate, and the side wall of the substrate holding portion 31a presses the end face T.
  • the substrate 10 rotates on the upper and lower surface plates.
  • the substrate 10 is sandwiched between the upper surface plate 32 having the polishing surface 34 and the lower surface plate 33 having the polishing surface 35 so as to apply a predetermined pressure. .
  • a large force is applied to the end surface T because the end surface T is pushed by the side wall of the substrate holding portion 31 of the carrier 31 while the substrate 10 is pressed between the two polishing surfaces having a high frictional force.
  • the center of the substrate 10 is rotated as an axis, a force is not applied equally to the entire end face T, but a half region on the side of the rotation direction from the substrate symmetry line 11a, for example, the substrate 10 as shown in FIG. 5A.
  • the pressure per unit area applied to the substrate 10 by the upper surface plate 32 and the lower surface plate 33 is double-side polishing of the main surface of the glass substrate for LSI mask blank. Apply the same pressure as in. That is, since the area of the main surface 11 is much larger in the large mask blank substrate 10, the applied load becomes very large.
  • the ratio of the length of the main surface side (long side) of the end face to the thickness (length of the short side) of the large mask blank substrate 10 is larger than that of the LSI substrate. That is, the large mask blank substrate 10 has a smaller area ratio of the end surface to the main surface, and a larger force is applied than the LSI mask blank substrate. The area ratio of the end surface to the main surface becomes more prominent because the thickness does not increase so much as the size increases.
  • the glass chip is formed on the end face T in the case where the entire entire circumference of the end face is polished (not mirror-polished) or the surface roughness Ra is set to about 0.03 to 0.4 ⁇ m (Patent Documents 1 and 2).
  • Patent Documents 1 and 2 When a strong force is applied, it occurs when a minute convex part on the surface peels off. From these verifications, the present inventors have increased the size of the large-size mask blank substrate, so that each end face T is pushed by the side wall of the substrate holding portion 31a of the carrier 31 during double-side polishing. It was concluded that the generation rate of glass chips was also increased as the force applied to the region of a predetermined length from the corner P of the substrate in the side direction of the main surface continued to increase.
  • At least the corner side region in the vicinity of the four corners of the end surface T is subjected to predetermined mirror polishing, and the center surface region on the center side of the end surface T is subjected to rough surface polishing.
  • the large mask blank substrate 10 that cannot mirror-polish the entire end face T the generation of glass chips and the generation of abrasive residue are suppressed, and surface defect countermeasures or dust generation countermeasures are taken. .
  • the end surface T of the substrate is subjected to the mirror polishing prescribed in the present application and then put into the polishing process of the main surface 11, thereby suppressing the generation of glass chips and the accompanying surface defect generation rate.
  • production of particles, such as a polishing residue, can be reduced is also acquired.
  • the effect can be sufficiently obtained by subjecting only the vicinity of the four corners of the substrate, which is a portion that strongly strikes the polishing carrier for holding the substrate, to the predetermined mirror polishing.
  • the present invention has the following configuration.
  • (Configuration 1) In a mask blank substrate having a chamfered surface between the end surface and the main surface, which is a thin plate composed of two main surfaces on the front and back sides and four end surfaces, The main surface has a side length of 500 mm or more, The end surface includes two corner side regions that are in a range of a predetermined length in a side direction on the main surface side from a corner portion adjacent to the end surface, and a central region sandwiched between the two corner side regions. Consists of The surface roughness Ra of the end surface of the corner side region is a mirror surface having a thickness of 0.5 nm or less, A mask blank substrate, wherein the central region is a rough surface.
  • the mask blank substrate of the present invention is a thin plate composed of two main surfaces on the front and back and four end surfaces, and a mask blank substrate having a chamfered surface between the end surface and the main surface,
  • the main surface has a side length of 500 mm or more
  • the end face includes two corner side areas that are areas having a predetermined length in a side direction of the main surface from a corner part where adjacent end faces contact each other, and a central side area sandwiched between the two corner side areas.
  • Consists of The surface roughness Ra of the end surface of the corner side region is a mirror surface having a thickness of 0.5 nm or less,
  • the central region is a rough surface (Configuration 1).
  • the mask blank substrate of the present invention is a thin plate composed of two main surfaces, front and back, and four end surfaces, and has a chamfered surface between the end surfaces and the main surface (Configuration 1).
  • the thin plate is composed of two main surfaces 11 and four end surfaces T, and a chamfered surface C is provided between the end surface T and the main surface 11.
  • the main surface 11 has a side length of 500 mm or more (Configuration 1).
  • the length of the short side L2 is 500 mm or more.
  • the end face includes a corner side area in a range of a predetermined length in a side direction of the main surface from a corner part where the end faces contact each other, and a center side area sandwiched between both corner side areas.
  • the end face T has a predetermined length (the length of the side L4) in the direction of the long side L1 of the main surface 11 from the corner where the end faces T contact each other. It consists of a region 13 and a central region 14 sandwiched between both corner regions 13.
  • the surface roughness Ra of the end face of the corner portion region is a mirror surface having a thickness of 0.5 nm or less (Configuration 1).
  • the surface roughness Ra of the end surface T of the corner portion region 13 is a mirror surface having a thickness of 0.5 nm or less.
  • the surface roughness Ra of the end face T in the corner side region is 0.3 nm or less because the particle generation rate can be further reduced.
  • the central region is a rough surface (Configuration 1).
  • the central region 14 is a rough surface.
  • the corner side regions of the four end surfaces are mirror surfaces, and the central side regions of the four end surfaces are rough surfaces. did.
  • maintenance part 31a of the carrier 31 is a mirror surface, the problem of a glass chip can also be solved.
  • the central region is preferably a rough surface having a surface roughness Ra of 50 nm or more (Configuration 2). This is because the handling problem can be solved more effectively.
  • region made into a rough surface it is desirable to set it as 400 nm. When the surface roughness Ra is rougher than 400 nm, the problem of particle generation becomes significant.
  • the center side region as a rough surface is set to have a surface roughness Ra of 300 nm or less, the generation rate of particles can be further reduced, and it is optimal that the surface roughness Ra is 200 nm or less.
  • the predetermined length is preferably 100 mm or more (Configuration 3). This is because the problem of the glass chip can be solved more effectively.
  • the length of one side of the main surface is 1000 mm or more and the predetermined length is 150 mm or more (Configuration 4).
  • the predetermined length is 200 mm or more because the generation rate of glass chips and particles can be further reduced. If there is no problem in handling and no problem in substrate detection, it is optimal to set the predetermined length to 300 mm or more because the generation rate of glass chips and particles can be further reduced.
  • the central region includes a region to be gripped when the substrate is transported (Configuration 5). This is because the handling problem can be more effectively solved if the central region includes a region gripped when the substrate is transported.
  • a mask inspection device for inspecting a transfer pattern formed on a large mask an exposure drawing device for exposing and drawing a transfer pattern on a resist film formed on a mask blank, an exposure device, etc. The presence or absence of a large mask blank or a large mask on the stage may be detected by applying light to the end face T. In such a case, it is effective to make the central region rough.
  • the mask blank substrate of the present invention may be used when manufacturing a photomask blank for a flat panel display (Configuration 6).
  • the mask blank substrate of the present invention may have a thin film on the main surface (Configuration 7).
  • the mask blank substrate of the present invention may have a thin film pattern on the main surface (Configuration 8).
  • the corner area in the vicinity of the four corners of the substrate where a very large force is applied among the end surfaces is mirror-polished, thereby reducing the incidence of glass chips. It is possible to greatly reduce the surface defect occurrence rate, and at the time of polishing the main surface of the substrate, the central area of the substrate with a relatively small force is used as a rough surface so that it can be handled. It is possible to provide a mask blank substrate that can be easily handled.
  • FIG. 1 is a view showing the structure of a mask blank substrate according to the present invention
  • FIG. 1A is a side view of the mask blank substrate
  • FIG. 1B is a top view
  • FIG. 1C is a partially enlarged view of the side.
  • the mask blank substrate 10 according to the present embodiment is a thin plate composed of two main surfaces 11 and four end surfaces T, and the end surface T and the main surface 11 are between them. It has a chamfered surface C.
  • FIG. 1 is a view showing the structure of a mask blank substrate according to the present invention
  • FIG. 1A is a side view of the mask blank substrate
  • FIG. 1B is a top view
  • FIG. 1C is a partially enlarged view of the side.
  • the mask blank substrate 10 according to the present embodiment is a thin plate composed of two main surfaces 11 and four end surfaces T, and the end surface T and the main surface 11 are between them. It has a chamfered surface C.
  • FIG. 1 is a view showing the structure of
  • the main surface 11 has a substantially rectangular shape having a pair of long sides L1 (the length of the long side L1: 800 mm) and a pair of short sides L2 (the length of the short side L2: 500 mm). is there.
  • the end face T has a corner portion region 13 in a range of 100 mm (length of the side L4: a predetermined length) in a side direction of the main surface 11 from a corner portion where the end faces contact each other,
  • the end surface T of the corner portion region 13 is a mirror surface having a surface roughness Ra of 0.1 nm
  • the center portion region 14 is a rough surface.
  • the side surface 12 of the mask blank substrate 10 has a chamfered surface C and an end surface T sandwiched between the double-sided chamfered surfaces C.
  • the end face T has a substantially rectangular shape having a pair of long sides (long side L1 or short side L2) and a pair of short sides L3 (length of short side L3: 8.2 mm).
  • 14 is a region to be gripped when the substrate is transported, and when this state is viewed from the upper surface of the substrate, four corner portions (portions corresponding to the corner side region 13) of the substrate are shown in FIG.
  • the central region 14 is a rough surface having a surface roughness Ra of 50 nm, and the length of the side surface 12 (substrate thickness) is 10 mm.
  • the large mask blank substrate 10 is a substrate having one side (preferably each side) of 500 mm or more on a rectangular or square substrate.
  • the large mask blank substrate 10 currently has various sizes in the range of 500 mm ⁇ 800 mm to 2140 mm ⁇ 2460 mm in the short side L2 ⁇ long side L1, and the thickness (the length of the side surface 12) is 10 to 15 mm. is there.
  • the size of the long side L1 of the substrate is 800 mm or more
  • the force applied to the corner side region of the end face is considerably large, and when it is 1200 mm or more, the force applied to the corner side region of the end face is very large.
  • the effect of applying the present invention is very large.
  • the predetermined mirror surface refers to a surface having a surface roughness Ra of 0.5 nm or less
  • the predetermined rough surface refers to a surface having a surface roughness Ra of 50 nm or more.
  • the corner side region 13 constituting the end face T is mirror-polished with a surface roughness Ra of 0.1 nm, and the central region 14 is rough-polished with a surface roughness Ra of 50 nm. 10 is an example.
  • FIG. 2 is a diagram for explaining a method of mirror polishing the end face.
  • the corner side region 13 in the figure, the hatched portion
  • the present invention is not limited to this, and any other polishing method may be used as long as the corner side region 13 can be mirror-polished.
  • FIGS. 3A and 3B are diagrams for explaining the outline of the main surface polishing step according to the present invention, in which FIG. 3A is a top view and FIG. 3B is a side view.
  • the end surface T of the substrate 10 is held by a carrier 31, and the substrate 10 is placed between a polishing surface 34 of an upper surface plate 32 and a polishing surface 35 of a lower surface plate 33 provided so as to face each other vertically.
  • the two main surfaces 11 of the substrate 10 are held in contact with each other.
  • the upper and lower surface plates 32 and 33 are rotated with the vertical axes of the upper and lower surface plates perpendicular to the polishing surfaces 34 and 35 of the upper and lower surface plates as rotation axes O1 and O2, respectively, and the rotation axis O3 of the substrate 10 is rotated.
  • the substrate 10 is determined to be eccentric in parallel to the rotation axis O2 of the lower surface plate and a part of the substrate 10 is positioned on the rotation axis O2 of the lower surface plate, and the substrate is rotated by rotating the carrier 31.
  • the main surfaces 11 of the substrate are polished by the relative movement of the polishing surfaces 34 and 35 of the upper and lower surface plates and the main surfaces 11 of the substrate in contact with each other. During the polishing process, the pressure applied to both main surfaces 11 of the substrate 10 was 100 g / cm 2 .
  • Such a polishing process of the main surface 11 may be performed a plurality of times, and the polishing process of the main surface 11 having different contents may be performed.
  • a polishing cloth made of hard polisher is used for the polishing surfaces 34 and 35 to perform the first polishing process first, and then a polishing cloth made of soft polisher is used for the polishing faces 34 and 35 to perform the second polishing process. You may do it.
  • the mask blank substrate 10 having higher flatness can be manufactured by repeating the polishing process of the main surface 11 a plurality of times.
  • the generation rate of the substrate in which surface defects are detected on the main surface of the substrate can be reduced to about 3%.
  • the detection rate could be reduced to about 5%, and the yield was very high.
  • the polishing yield and the cleaning yield of the mask blank substrate 10 can be improved.
  • FIG. (1) The processing time required for mirror polishing of the end face of the substrate can be shortened. (2) When handling manually, it can be done without any particular problem.
  • the length of the long side L1 is 1220 mm
  • the length of the short side L2 is 1400 mm
  • the length of the short side L3 is 10.6 mm
  • the length of the side L4 is 150 mm
  • the thickness of the substrate is 13 mm.
  • the surface roughness Ra of the corner side region 13 is 0.05 nm
  • the surface roughness Ra of the central side region 14 is 500 nm (the surface having a surface roughness Ra of 500 nm is cloudy by visual observation)
  • the central side region 14 is It includes an area irradiated with detection light for detecting the photomask when the substrate is placed on the mask stage 52 of the exposure apparatus. In addition, handling was performed using a machine instead of a human hand.
  • the generation rate of the substrate in which surface defects are detected on the main surface of the substrate can be reduced to about 3%.
  • the detection rate could be reduced to about 5%, and the yield was very high.
  • Comparative Example 1 the entire end face of the mask blank substrate 10 having a size of 500 mm ⁇ 800 mm and a thickness of 10 mm was a rough surface having a surface roughness Ra of 50 nm.
  • both main surfaces 11 of the mask blank substrate 10 were mirror-polished by the same polishing method as in the above-described embodiment.
  • a defect inspection was performed.
  • the occurrence rate of the substrate on which surface defects were detected on the main surface of the substrate was as high as about 20%.
  • the occurrence rate was as high as about 30%, resulting in a low yield.
  • Comparative Example 2 In this comparative example, the entire end face of the mask blank substrate 10 having a size of 1220 mm ⁇ 1400 mm and a thickness of 13 mm was used as a mirror surface having a surface roughness Ra of 1.0 nm.
  • both main surfaces 11 of the mask blank substrate 10 were mirror-polished by the same polishing method as in the above-described embodiment.
  • a defect inspection was performed.
  • the occurrence rate of the substrate in which surface defects were detected on the main surface of the substrate was as high as about 30%.
  • the occurrence rate was as high as about 40%, resulting in a low yield.
  • the entire center side region 14 is a rough surface.
  • the end surface T of the central region 14 excluding those specific regions may be a mirror surface having a surface roughness that is the same as or higher than that of the corner region.
  • the specific region of the central region 14 that needs to be roughened in relation to the substrate detection is determined in advance. For example, not only the size of the substrate, but only the area that needs to be the rough surface of the central region 14 is the rough surface, and the other central region 14 is the same as the corner region.
  • the corner side regions on both sides from the substrate symmetry line of the central side region 14 are predetermined in order to further reduce the generation rate of glass chips and the generation rate of particles caused by sticking of the abrasive. It is good also as a structure which makes surface roughness small in steps for every distance.
  • the shape of the mask blank substrate 10 is not limited to a rectangle, and may be a square in which one side of the main surface 11 is 500 mm or more.

Abstract

A substrate for mask blank use, which is a thin plate comprised of two primary faces which are front and back faces and four edge faces, is provided with chamfered faces between the edge faces and the primary faces. The length of one side of a primary face is 500 mm or greater. In addition, the edge faces are provided with two corner part side regions, which are regions such that from the corner part where adjacent edge faces meet in the direction of the edge of a primary face is in the range of a prescribed length (the length of side (L4)), and a central side region which is sandwiched between those two corner part side regions. The edge faces of the corner part side regions are mirrored surfaces with a surface roughness (Ra) of 0.5 nm or less, while the central side region has a rough surface.

Description

マスクブランク用基板、マスクブランクおよびフォトマスクMask blank substrate, mask blank and photomask
　本発明は、マスクブランク用基板に関し、特にＦＰＤデバイスを製造するための大型マスクブランク用基板に関する。 The present invention relates to a mask blank substrate, and more particularly to a large mask blank substrate for manufacturing an FPD device.
　近年の電子デバイス、特に半導体素子や液晶モニター用のカラーフィルターあるいはＴＦＴ素子等は、ＩＴ技術の急速な発達に伴い、より一層の微細化が要求されている。このような微細加工技術を支える技術の一つが、転写マスクと呼ばれるフォトマスクを用いたリソグラフィー技術である。このリソグラフィー技術においては、露光用光源の電磁波乃至光波をフォトマスクを通してレジスト膜付きシリコンウエハー等に露光することにより、シリコンウエハー上に微細なパターンを形成している。このフォトマスクは通常、透光性基板上に遮光性膜等の薄膜を形成したマスクブランクにリソグラフィー技術を用いて前記薄膜をパターニングすることにより転写パターンとなる薄膜パターンを形成して製造される。 Recent electronic devices, particularly semiconductor elements, color filters for liquid crystal monitors, TFT elements, and the like, are required to be further miniaturized with the rapid development of IT technology. One of the technologies that support such a fine processing technology is a lithography technology using a photomask called a transfer mask. In this lithography technique, a fine pattern is formed on a silicon wafer by exposing an electromagnetic wave or light wave of an exposure light source to a silicon wafer with a resist film through a photomask. This photomask is usually manufactured by forming a thin film pattern to be a transfer pattern by patterning the thin film using a lithography technique on a mask blank in which a thin film such as a light-shielding film is formed on a translucent substrate.
　ところで、パターンの微細化を達成するためには、フォトマスクを製造するための原版となるマスクブランクの品質の向上も極めて重要である。半導体用のフォトマスクでは、基板の主表面を鏡面研磨するとともに、基板の主表面の周縁に形成された端面についても所定の鏡面となるように研磨を施していた。しかしながら、液晶ディスプレイ、有機エレクトロルミネッセンスディスプレイ、プラズマパネルディスプレイ等のフラットパネルディスプレイ（ＦＰＤ：Flat Panel Display）の大型フォトマスクにおいては、開発当初は端面を鏡面にする要求はなく、端面は粗面のままであった。このように、端面が粗面の場合、端面に付着した研磨剤やガラス成分等の汚れが洗浄では除去しきれず、洗浄後にそこから剥離して基板の主表面や主表面上に形成された薄膜やレジスト膜に付着してしまい、パーティクルの発生要因となってしまっており、それが歩留りの低下要因となっていた。 By the way, in order to achieve pattern miniaturization, it is extremely important to improve the quality of a mask blank that is an original plate for manufacturing a photomask. In a semiconductor photomask, the main surface of the substrate is mirror-polished, and the end surface formed on the periphery of the main surface of the substrate is also polished to have a predetermined mirror surface. However, for large-sized photomasks of flat panel displays (FPD: Flat Panel Display) such as liquid crystal displays, organic electroluminescence displays, and plasma panel displays, there is no requirement for the end face to be a mirror surface at the beginning of development, and the end face remains rough. Met. Thus, when the end surface is rough, dirt such as abrasives and glass components adhering to the end surface cannot be completely removed by cleaning, and the thin film formed on the main surface or main surface of the substrate is peeled off after cleaning. And adhere to the resist film, which is a cause of the generation of particles, which is a cause of a decrease in yield.
　図４は、大型マスクブランク用基板を示す斜視図である。この大型マスクブランク用基板１０は、表裏２つの主表面１１と４つの端面Ｔとを有している。上述した歩留まりの悪化を引き起こすという問題を解決するために、大型マスクブランク用基板１０の端面Ｔを鏡面にすることが考えられる。 FIG. 4 is a perspective view showing a large mask blank substrate. The large mask blank substrate 10 has two main surfaces 11 and four end surfaces T. In order to solve the problem of causing the above-described deterioration of the yield, it is conceivable to make the end surface T of the large mask blank substrate 10 a mirror surface.
　しかしながら、大型マスクブランク用基板１０については開発当初、大型マスクブランク用基板１０の取り扱いを機械化することが難しかったため、人手で端面Ｔを挟むように持ったりすることが行われていた。この場合、端面Ｔをハンドリングする際、ハンドリング用手袋と大型マスクブランク用基板１０間で滑ってしまい、大型マスクブランク用基板１０を持つことができないという問題があった。 However, since it was difficult to mechanize the handling of the large mask blank substrate 10 at the beginning of development, the large mask blank substrate 10 was manually held so as to sandwich the end face T. In this case, when the end surface T is handled, there is a problem that the large mask blank substrate 10 cannot be held due to slipping between the handling gloves and the large mask blank substrate 10.
　上記の問題を解決するために、露光用大型基板において、例えば端面を基板が濡れた状態で人が把持する際に滑り落ちないような面粗さとすること、具体的には端面の表面粗さＲａを０．０５～０．４μｍ程度にすること（特開２００５－３７５８０号公報（特許文献１））または、端面の表面粗さＲａを例えば０．０３～０．３μｍにすること（特開２００５－３００５６６号公報（特許文献２））が提案されている。 In order to solve the above problems, in a large-sized substrate for exposure, for example, the end surface should have a surface roughness that does not slip when a person grips the substrate while the substrate is wet. Specifically, the surface roughness of the end surface Ra is set to about 0.05 to 0.4 μm (Japanese Patent Laid-Open No. 2005-37580 (Patent Document 1)), or the surface roughness Ra of the end face is set to 0.03 to 0.3 μm, for example (Japanese Patent Laid-Open No. 2005-37580). 2005-3005626 (Patent Document 2)) has been proposed.
特開２００５－３７５８０号公報JP 2005-37580 A 特開２００５－３００５６６号公報（特許第３９３４１１５号公報）JP 2005-300566 A (Patent No. 3934115)
　特許文献１、２記載の露光用大型基板においては、それらの出願当時、ＦＰＤ用等の大型フォトマスクは、転写パターン線幅が比較的広く、マスクブランクに微小のパーティクルが付着することに起因する悪影響よりも、上記のそのほかの問題の方が重要であった。
しかし、その後、大型フォトマスクにおいても転写パターン線幅の微細化が進み、パーティクルの影響は無視し難くなってきている。また、ＦＰＤ等の大型化やＦＰＤ製造の効率化に伴い、マスクブランクの大型化が進んできている。それに伴い、従来の端面全周を粗面研磨する（鏡面研磨しない）場合や端面Ｔの表面粗さＲａを０．０３～０．４μｍ程度にする場合（特許文献１、２）、以前よりも基板研磨時の端面からのガラスチップの発生が増大してきており、問題となっていた。 In the large substrates for exposure described in Patent Documents 1 and 2, large photomasks for FPDs and the like at the time of their filing are due to the relatively wide transfer pattern line width and minute particles adhering to the mask blank. The other problems mentioned above were more important than the adverse effects.
However, since the transfer pattern line width has been further refined even in large photomasks, the influence of particles has become difficult to ignore. In addition, with the increase in size of FPDs and the like and the efficiency of FPD production, the size of mask blanks has been increasing. Along with this, when the conventional entire end face is subjected to rough polishing (no mirror polishing) or when the surface roughness Ra of the end face T is set to about 0.03 to 0.4 μm (Patent Documents 1 and 2), The generation of glass chips from the end surface during substrate polishing has been increasing, which has been a problem.
　本発明は、上述した問題を解決するためになされたものであり、研磨の際の端面からのガラスチップや研磨剤残留物等のパーティクルの発生、及びそれに伴う表面欠陥発生率を低く抑えることができるマスクブランク用基板を提供することを目的とする。 The present invention has been made to solve the above-described problems, and it is possible to suppress the generation of particles such as glass chips and abrasive residues from the end face during polishing, and the rate of occurrence of surface defects associated therewith. An object of the present invention is to provide a mask blank substrate.
　本発明者らは、以下のことを解明した。図５Ａ～図５Ｃは、ガラスチップの発生を説明するための図であり、図５Ａは主表面の研磨時（主表面右回転）の状態を示す上面図、図５Ｂは主表面の研磨時（主表面左回転）の状態を示す上面図、図５Ｃは主表面の研磨時における端面及びキャリアの側面図である。同図に示すように、基板１０はキャリア３１の基板保持部３１ａで保持された状態で、キャリア３１が回転基板の中心と同軸で回転し、基板保持部３１ａの側壁が端面Ｔを押すことで、基板１０は上下定盤上を回転する。また、基板１０の表裏両方の主表面１１を研磨するために研磨面３４を有する上定盤３２と研磨面３５を有する下定盤３３との間に所定の圧力が掛かる様にして挟まれている。摩擦力の高い２つの研磨面に挟まれて加圧された状態の基板１０をキャリア３１の基板保持部３１の側壁で端面Ｔを押すことから、端面Ｔには大きな力が掛かることになる。しかも、基板１０の中心を軸に回転させることから、端面Ｔの全面に等しく力が掛かるのではなく、基板対称線１１ａから回転進行方向側の半分の領域、たとえば、図５Ａのように基板１０を時計回りに回転させる場合は、端面Ｔの領域Ｔ１にほとんどの力が加わる。そして、同じ領域Ｔ１内でも基板対称線１１ａから端面同士が接する角部Ｐ近傍に向かって、掛かる力が増大していく荷重分布になる。また、基板１０を反時計回りに回転させる場合は、図５Ｂに示すように、今度は端面Ｔの領域Ｔ２で同様の傾向の荷重分布になる。同じ基板１０の研磨は、時計回りと反時計回りでの両方の研磨を行うので、領域Ｔ１、Ｔ２ともに荷重が加わる。このため、基板１０の主表面１１の研磨中は、領域Ｔ１と領域Ｔ２の角部Ｐから所定長さの領域（すなわち、各端面Ｔの基板の角部Ｐから主表面の辺方向に所定長さの領域）には、非常に強い力が加わることになる。さらに、主表面１１を研磨するために上定盤３２、下定盤３３ともに同軸で回転している。上下定盤３２，３３の回転方向と、基板１０の回転方向が異なる方向の場合、加圧された状態で接触している摩擦力の高い研磨面３４，３５の回転方向に抗して基板１０を回転させることから、領域Ｔ１と領域Ｔ２の角部Ｐから所定長さの領域には、より強い力が加わることになる。 The present inventors have elucidated the following. FIGS. 5A to 5C are diagrams for explaining the generation of glass chips, FIG. 5A is a top view showing a state of polishing the main surface (right rotation of the main surface), and FIG. 5B is a view of polishing the main surface ( FIG. 5C is a side view of the end surface and the carrier during polishing of the main surface. As shown in the figure, the substrate 10 is held by the substrate holding portion 31a of the carrier 31, and the carrier 31 rotates coaxially with the center of the rotating substrate, and the side wall of the substrate holding portion 31a presses the end face T. The substrate 10 rotates on the upper and lower surface plates. Further, in order to polish both the front and back main surfaces 11 of the substrate 10, the substrate 10 is sandwiched between the upper surface plate 32 having the polishing surface 34 and the lower surface plate 33 having the polishing surface 35 so as to apply a predetermined pressure. . A large force is applied to the end surface T because the end surface T is pushed by the side wall of the substrate holding portion 31 of the carrier 31 while the substrate 10 is pressed between the two polishing surfaces having a high frictional force. In addition, since the center of the substrate 10 is rotated as an axis, a force is not applied equally to the entire end face T, but a half region on the side of the rotation direction from the substrate symmetry line 11a, for example, the substrate 10 as shown in FIG. 5A. Is rotated clockwise, most force is applied to the region T1 of the end face T. Even in the same region T1, the load distribution is such that the applied force increases from the substrate symmetry line 11a to the vicinity of the corner P where the end faces contact each other. When the substrate 10 is rotated counterclockwise, the load distribution has the same tendency in the region T2 of the end face T, as shown in FIG. 5B. Since the same substrate 10 is polished in both clockwise and counterclockwise directions, a load is applied to the regions T1 and T2. For this reason, during polishing of the main surface 11 of the substrate 10, a region having a predetermined length from the corner portion P of the region T1 and the region T2 (that is, a predetermined length in the side direction of the main surface from the corner portion P of the substrate at each end face T). In this area, a very strong force is applied. Further, both the upper surface plate 32 and the lower surface plate 33 rotate coaxially in order to polish the main surface 11. When the rotation direction of the upper and lower surface plates 32 and 33 is different from the rotation direction of the substrate 10, the substrate 10 opposes the rotation direction of the polishing surfaces 34 and 35 with high frictional force that are in contact with each other under pressure. Therefore, a stronger force is applied to the region having a predetermined length from the corner portion P of the region T1 and the region T2.
　大型マスクブランク用基板１０における主表面１１の両面研磨の場合でも、上定盤３２と下定盤３３とで基板１０に掛ける単位面積当たりの圧力は、ＬＳＩマスクブランク用ガラス基板の主表面の両面研磨の場合と同程度の圧力を加える。つまり、大型マスクブランク用基板１０の方がはるかに主表面１１の面積が大きいので、掛かる荷重も非常に大きくなる。一方、端面の主表面側（長辺側）の長さと、厚さ（短辺側の長さ）との比率は、ＬＳＩ基板に比べて、大型マスクブランク用基板１０の方が大きい。つまり、大型マスクブランク用基板１０の方が、主表面に対する端面の面積比率が小さく、ＬＳＩマスクブランク用基板よりも大きな力が加わってしまうことになる。この主表面に対する端面の面積比率は、サイズが大きくなっても厚さはさほど厚くならないことから、より顕著になる。 Even in the case of double-side polishing of the main surface 11 in the large mask blank substrate 10, the pressure per unit area applied to the substrate 10 by the upper surface plate 32 and the lower surface plate 33 is double-side polishing of the main surface of the glass substrate for LSI mask blank. Apply the same pressure as in. That is, since the area of the main surface 11 is much larger in the large mask blank substrate 10, the applied load becomes very large. On the other hand, the ratio of the length of the main surface side (long side) of the end face to the thickness (length of the short side) of the large mask blank substrate 10 is larger than that of the LSI substrate. That is, the large mask blank substrate 10 has a smaller area ratio of the end surface to the main surface, and a larger force is applied than the LSI mask blank substrate. The area ratio of the end surface to the main surface becomes more prominent because the thickness does not increase so much as the size increases.
　ガラスチップは、従来の端面全周を粗面研磨する（鏡面研磨しない）場合や表面粗さＲａを０．０３～０．４μｍ程度にする場合（特許文献１、２）の場合の端面Ｔに強い力が加わると、表面の微小な凸部が剥がれることで発生する。これらの検証から、本発明者らは、大型マスクブランク用基板のサイズの大型化が進んだことにより、両面研磨時における、キャリア３１の基板保持部３１ａの側壁に押されることによる各端面Ｔの基板の角部Ｐから主表面の辺方向に所定長さの領域に掛かる力が増大し続けることにより、ガラスチップの発生率も増大しているという結論にいたった。また、端面Ｔの中央側領域については、基板の粗面とすることによるガラスチップの発生率に、基板のサイズの大型化はほとんど影響を与えないという結論に至った。そして、本発明者らは、各端面Ｔの中央側領域の一部を粗面とし、基板の角部Ｐから主表面の辺方向に所定長さの領域を表面粗さ０．５ｎｍ以下の鏡面とすることで、ガラスチップの発生を抑制し、それに伴う基板主表面の表面欠陥（キズ）の発生率を大幅に抑えることができることを見出した。 The glass chip is formed on the end face T in the case where the entire entire circumference of the end face is polished (not mirror-polished) or the surface roughness Ra is set to about 0.03 to 0.4 μm (Patent Documents 1 and 2). When a strong force is applied, it occurs when a minute convex part on the surface peels off. From these verifications, the present inventors have increased the size of the large-size mask blank substrate, so that each end face T is pushed by the side wall of the substrate holding portion 31a of the carrier 31 during double-side polishing. It was concluded that the generation rate of glass chips was also increased as the force applied to the region of a predetermined length from the corner P of the substrate in the side direction of the main surface continued to increase. In addition, for the central region of the end face T, it was concluded that the increase in the size of the substrate hardly affects the glass chip generation rate due to the rough surface of the substrate. Then, the inventors make a part of the central region of each end face T a rough surface, and a region having a predetermined length from the corner P of the substrate to the side of the main surface is a mirror surface having a surface roughness of 0.5 nm or less. Thus, it has been found that the generation of glass chips can be suppressed, and the rate of occurrence of surface defects (scratches) on the main surface of the substrate can be greatly suppressed.
　本発明において、少なくとも、端面Ｔの４隅側付近の角部側領域に対して本願所定の鏡面研磨を行い、端面Ｔの中央側の中央側領域に対して粗面研磨を行うことには、以下の２つの理由がある。
（１）端面Ｔの全面を鏡面研磨することができない大型マスクブランク用基板１０に対して、ガラスチップの発生や研磨剤残留物の発塵を抑制し、表面欠陥対策または発塵対策を行うこと。
（２）基板の加工時間を短縮すること。
　端面Ｔの全面を鏡面研磨する場合に比べて、端面研磨の加工時間を短縮することができる。その結果、加工におけるコストダウンが実現できる。 In the present invention, at least the corner side region in the vicinity of the four corners of the end surface T is subjected to predetermined mirror polishing, and the center surface region on the center side of the end surface T is subjected to rough surface polishing. There are two reasons.
(1) With respect to the large mask blank substrate 10 that cannot mirror-polish the entire end face T, the generation of glass chips and the generation of abrasive residue are suppressed, and surface defect countermeasures or dust generation countermeasures are taken. .
(2) To reduce the processing time of the substrate.
Compared with the case where the entire end face T is mirror-polished, the processing time for end face polishing can be shortened. As a result, cost reduction in processing can be realized.
　大型マスクブランクの製造工程においては、基板の端面Ｔに本願所定の鏡面研磨を施した後に主表面１１の研磨工程へ投入することにより、ガラスチップの発生及びそれに伴う表面欠陥発生率を低く抑えることができるという効果が得られる。また、研磨残留物等のパーティクルの発生を低減することができる効果も得られる。発明者らによる試験の結果、基板保持の研磨キャリアに強く当たる部分である基板の４隅付近のみを本願所定の鏡面研磨することによって、その効果を十分に得られることが確認できた。 In the manufacturing process of the large mask blank, the end surface T of the substrate is subjected to the mirror polishing prescribed in the present application and then put into the polishing process of the main surface 11, thereby suppressing the generation of glass chips and the accompanying surface defect generation rate. The effect of being able to be obtained. Moreover, the effect that generation | occurrence | production of particles, such as a polishing residue, can be reduced is also acquired. As a result of the tests by the inventors, it has been confirmed that the effect can be sufficiently obtained by subjecting only the vicinity of the four corners of the substrate, which is a portion that strongly strikes the polishing carrier for holding the substrate, to the predetermined mirror polishing.
　本発明は以下の構成を有する。
　（構成１）　表裏２つの主表面と、４つの端面とで構成される薄板であり、前記端面および前記主表面の間に面取り面を有するマスクブランク用基板において、
前記主表面は、一辺の長さが５００ｍｍ以上であり、
前記端面は、隣接する端面が接する角部から主表面側の辺方向に所定長さの範囲の領域である２つの角部側領域と、当該２つの角部側領域に挟まれる中央側領域とからなり、
前記角部側領域の端面の表面粗さＲａが０．５ｎｍ以下の鏡面であり、
前記中央側領域が粗面であることを特徴とするマスクブランク用基板。
　（構成２）　前記中央側領域は、表面粗さＲａが５０ｎｍ以上の粗面であることを特徴とする構成１記載のマスクブランク用基板。
　（構成３）　前記所定長さは、１００ｍｍ以上であることを特徴とする構成１または２に記載のマスクブランク用基板。
　（構成４）　前記主表面の一辺の長さが１０００ｍｍ以上であり、前記所定長さが１５０ｍｍ以上であることを特徴とする構成１または２に記載のマスクブランク用基板。
　（構成５）　前記中央側領域は、基板を運搬するときに把持される領域を含むことを特徴とする構成１乃至４のいずれかに記載のマスクブランク用基板。
　（構成６）　フラットパネルディスプレイのフォトマスクブランクを製造する際に用いられることを特徴とする構成１乃至４のいずれかに記載のマスクブランク用基板。
　（構成７）　構成１乃至５のいずれかに記載のマスクブランク用基板の主表面に、薄膜を有することを特徴とするマスクブランク。
　（構成８）　構成１乃至５のいずれかに記載のマスクブランク用基板の主表面に、薄膜パターンを有することを特徴とするフォトマスク。 The present invention has the following configuration.
(Configuration 1) In a mask blank substrate having a chamfered surface between the end surface and the main surface, which is a thin plate composed of two main surfaces on the front and back sides and four end surfaces,
The main surface has a side length of 500 mm or more,
The end surface includes two corner side regions that are in a range of a predetermined length in a side direction on the main surface side from a corner portion adjacent to the end surface, and a central region sandwiched between the two corner side regions. Consists of
The surface roughness Ra of the end surface of the corner side region is a mirror surface having a thickness of 0.5 nm or less,
A mask blank substrate, wherein the central region is a rough surface.
(Configuration 2) The mask blank substrate according to Configuration 1, wherein the central region is a rough surface having a surface roughness Ra of 50 nm or more.
(Structure 3) The mask blank substrate according to Structure 1 or 2, wherein the predetermined length is 100 mm or more.
(Configuration 4) The mask blank substrate according to Configuration 1 or 2, wherein a length of one side of the main surface is 1000 mm or more, and the predetermined length is 150 mm or more.
(Configuration 5) The mask blank substrate according to any one of Configurations 1 to 4, wherein the central region includes a region that is gripped when the substrate is transported.
(Structure 6) The mask blank substrate according to any one of Structures 1 to 4, which is used when a photomask blank for a flat panel display is manufactured.
(Structure 7) A mask blank, comprising a thin film on a main surface of the mask blank substrate according to any one of Structures 1 to 5.
(Configuration 8) A photomask having a thin film pattern on a main surface of the mask blank substrate according to any one of Configurations 1 to 5.
　以下、本発明を詳細に説明する。
　本発明のマスクブランク用基板は、表裏２つの主表面と、４つの端面とで構成される薄板であり、前記端面および前記主表面の間に面取り面を有するマスクブランク用基板において、
前記主表面は、一辺の長さが５００ｍｍ以上であり、
前記端面は、隣接する端面同士が接する角部から主表面の辺方向に所定長さの範囲の領域である２つの角部側領域と、当該２つの角部側領域に挟まれる中央側領域とからなり、
前記角部側領域の端面の表面粗さＲａが０．５ｎｍ以下の鏡面であり、
前記中央側領域が粗面であることを特徴とする（構成１）。 Hereinafter, the present invention will be described in detail.
The mask blank substrate of the present invention is a thin plate composed of two main surfaces on the front and back and four end surfaces, and a mask blank substrate having a chamfered surface between the end surface and the main surface,
The main surface has a side length of 500 mm or more,
The end face includes two corner side areas that are areas having a predetermined length in a side direction of the main surface from a corner part where adjacent end faces contact each other, and a central side area sandwiched between the two corner side areas. Consists of
The surface roughness Ra of the end surface of the corner side region is a mirror surface having a thickness of 0.5 nm or less,
The central region is a rough surface (Configuration 1).
　本発明のマスクブランク用基板は、表裏２つの主表面と、４つの端面とで構成される薄板であり、また端面および主表面の間に面取り面を有する（構成１）。
　例えば、本発明では、図１Ｃに示すように、表裏２つの主表面１１と、４つの端面Ｔとで構成される薄板であり、また端面Ｔおよび主表面１１の間に面取り面Ｃを有する。 The mask blank substrate of the present invention is a thin plate composed of two main surfaces, front and back, and four end surfaces, and has a chamfered surface between the end surfaces and the main surface (Configuration 1).
For example, in the present invention, as shown in FIG. 1C, the thin plate is composed of two main surfaces 11 and four end surfaces T, and a chamfered surface C is provided between the end surface T and the main surface 11.
　また、本発明のマスクブランク用基板において、主表面１１は、一辺の長さが５００ｍｍ以上である（構成１）。
　例えば、本発明では、図１Ｂに示すように、短辺Ｌ２の長さが５００ｍｍ以上である。 In the mask blank substrate of the present invention, the main surface 11 has a side length of 500 mm or more (Configuration 1).
For example, in the present invention, as shown in FIG. 1B, the length of the short side L2 is 500 mm or more.
　また、本発明のマスクブランク用基板において、端面は、端面同士が接する角部から主表面の辺方向に所定長さの範囲の角部側領域と、両角部側領域に挟まれる中央側領域とからなる（構成１）。
　例えば、本発明では、図１Ａに示すように、端面Ｔは、端面Ｔ同士が接する角部から主表面１１の長辺Ｌ１方向に所定長さ（辺Ｌ４の長さ）の範囲の角部側領域１３と、両角部側領域１３に挟まれる中央側領域１４とからなる。 Further, in the mask blank substrate of the present invention, the end face includes a corner side area in a range of a predetermined length in a side direction of the main surface from a corner part where the end faces contact each other, and a center side area sandwiched between both corner side areas. (Configuration 1).
For example, in the present invention, as shown in FIG. 1A, the end face T has a predetermined length (the length of the side L4) in the direction of the long side L1 of the main surface 11 from the corner where the end faces T contact each other. It consists of a region 13 and a central region 14 sandwiched between both corner regions 13.
　また、本発明のマスクブランク用基板において、角部側領域の端面の表面粗さＲａが０．５ｎｍ以下の鏡面である（構成１）。
　例えば、本発明では、図１Ａに示すように、角部側領域１３の端面Ｔの表面粗さＲａが０．５ｎｍ以下の鏡面である。なお、角部側領域の端面Ｔの表面粗さＲａは、０．３ｎｍ以下とすると、パーティクルの発生率をより低減でき、より好ましい。 Further, in the mask blank substrate of the present invention, the surface roughness Ra of the end face of the corner portion region is a mirror surface having a thickness of 0.5 nm or less (Configuration 1).
For example, in the present invention, as shown in FIG. 1A, the surface roughness Ra of the end surface T of the corner portion region 13 is a mirror surface having a thickness of 0.5 nm or less. In addition, it is more preferable that the surface roughness Ra of the end face T in the corner side region is 0.3 nm or less because the particle generation rate can be further reduced.
　また、本発明のマスクブランク用基板において、中央側領域が粗面である（構成１）。
　例えば、本発明では、図１Ａに示すように、中央側領域１４が粗面である。 In the mask blank substrate of the present invention, the central region is a rough surface (Configuration 1).
For example, in the present invention, as shown in FIG. 1A, the central region 14 is a rough surface.
　このように、本発明では、特定のサイズ（一辺の長さが５００ｍｍ以上）のマスクブランク用基板において、４つの端面の角部側領域を鏡面とし、４つの端面の中央側領域を粗面とした。これは、ハンドリング、ガラスチップの問題をすべて解決するためである。すなわち、中央側領域の一部領域が粗面となっているため、ハンドリングの問題を解決することができる。また、キャリア３１の基板保持部３１ａの側壁から受ける力が大きい角部側領域が鏡面となっているため、ガラスチップの問題も解決することができる。 Thus, in the present invention, in a mask blank substrate of a specific size (one side length of 500 mm or more), the corner side regions of the four end surfaces are mirror surfaces, and the central side regions of the four end surfaces are rough surfaces. did. This is to solve all the handling and glass chip problems. That is, since a partial area of the central area is a rough surface, the handling problem can be solved. Moreover, since the corner | angular part side area | region where the force received from the side wall of the board | substrate holding | maintenance part 31a of the carrier 31 is a mirror surface, the problem of a glass chip can also be solved.
　また、本発明のマスクブランク用基板において、中央側領域は、表面粗さＲａが５０ｎｍ以上の粗面であることが好ましい（構成２）。これは、ハンドリングの問題をより効果的に解決できるためである。なお、粗面とする中央側領域の表面粗さＲａの上限としては、４００ｎｍとすることが望ましい。表面粗さＲａで４００ｎｍよりも粗くするとパーティクルの発生率の問題が顕著になる。また、粗面とする中央側領域を表面粗さＲａで３００ｎｍ以下とするとよりパーティクルの発生率の低減が図れ、さらに表面粗さＲａで２００ｎｍ以下であると最適である。 In the mask blank substrate of the present invention, the central region is preferably a rough surface having a surface roughness Ra of 50 nm or more (Configuration 2). This is because the handling problem can be solved more effectively. In addition, as an upper limit of surface roughness Ra of the center side area | region made into a rough surface, it is desirable to set it as 400 nm. When the surface roughness Ra is rougher than 400 nm, the problem of particle generation becomes significant. In addition, when the center side region as a rough surface is set to have a surface roughness Ra of 300 nm or less, the generation rate of particles can be further reduced, and it is optimal that the surface roughness Ra is 200 nm or less.
　また、本発明のマスクブランク用基板において、所定長さは、１００ｍｍ以上であることが好ましい（構成３）。これは、ガラスチップの問題をより効果的に解決できるためである。 Further, in the mask blank substrate of the present invention, the predetermined length is preferably 100 mm or more (Configuration 3). This is because the problem of the glass chip can be solved more effectively.
　また、本発明のマスクブランク用基板において、主表面の一辺の長さが１０００ｍｍ以上であり、前記所定長さが１５０ｍｍ以上であることが好ましい（構成４）。これは、主表面の一辺の長さが１０００ｍｍ以上の場合においては、キャリア３１の基板保持部３１ａの側壁から受ける力が大きい領域は広くなり、所定長さが１５０ｍｍ以上であると、ハンドリング、ガラスチップの問題をより効果的に解決できるためである。なお、所定長さを２００ｍｍ以上とすると、ガラスチップやパーティクルの発生率をより低減でき、好ましい。また、ハンドリング上の問題や基板検出の問題がないのであれば、所定長さを３００ｍｍ以上とすると、ガラスチップやパーティクルの発生率をさらに低減でき、最適である。 In the mask blank substrate of the present invention, it is preferable that the length of one side of the main surface is 1000 mm or more and the predetermined length is 150 mm or more (Configuration 4). In the case where the length of one side of the main surface is 1000 mm or more, the region where the force received from the side wall of the substrate holding portion 31a of the carrier 31 is large is widened, and if the predetermined length is 150 mm or more, handling, glass This is because the chip problem can be solved more effectively. In addition, it is preferable that the predetermined length is 200 mm or more because the generation rate of glass chips and particles can be further reduced. If there is no problem in handling and no problem in substrate detection, it is optimal to set the predetermined length to 300 mm or more because the generation rate of glass chips and particles can be further reduced.
　また、本発明のマスクブランク用基板において、中央側領域は、基板を運搬するときに把持される領域を含むことが好ましい（構成５）。これは、中央側領域が基板を運搬するときに把持される領域を含むと、ハンドリングの問題をより効果的に解決できるためである。
　さらに、大型マスクブランクの欠陥検査装置、大型マスクに形成された転写パターンを検査するマスク検査装置、マスクブランクに形成されたレジスト膜に転写パターンを露光描画する露光描画装置、露光装置などにおいては、ステージ上の大型マスクブランクや大型マスクの有無を端面Ｔに光を当てて検出する場合がある。このような場合、中央側領域を粗面にしておくことは有効である。 In the mask blank substrate of the present invention, it is preferable that the central region includes a region to be gripped when the substrate is transported (Configuration 5). This is because the handling problem can be more effectively solved if the central region includes a region gripped when the substrate is transported.
Furthermore, in a large mask blank defect inspection device, a mask inspection device for inspecting a transfer pattern formed on a large mask, an exposure drawing device for exposing and drawing a transfer pattern on a resist film formed on a mask blank, an exposure device, etc. The presence or absence of a large mask blank or a large mask on the stage may be detected by applying light to the end face T. In such a case, it is effective to make the central region rough.
　また、本発明のマスクブランク用基板は、フラットパネルディスプレイのフォトマスクブランクを製造する際に用いられるようにしてもよい（構成６）。 Further, the mask blank substrate of the present invention may be used when manufacturing a photomask blank for a flat panel display (Configuration 6).
　また、本発明のマスクブランク用基板においては、主表面に、薄膜を有するようにしてもよい（構成７）。 Further, the mask blank substrate of the present invention may have a thin film on the main surface (Configuration 7).
　また、本発明のマスクブランク用基板は、主表面に、薄膜パターンを有するようにしてもよい（構成８）。 The mask blank substrate of the present invention may have a thin film pattern on the main surface (Configuration 8).
　本発明に係るマスクブランク用基板においては、基板主表面の研磨工程時に、端面の中でも非常に大きな力が掛かる基板の４隅付近の角部領域を鏡面研磨することで、ガラスチップの発生率を大幅に低減し、表面欠陥発生率を低く抑えることができ、かつ、基板主表面の研磨工程時に、比較的力の掛かり具合の小さい基板の中央側領域を粗面とすることで、ハンドリング時等の取扱いが容易なマスクブランク用基板を提供することができる。 In the mask blank substrate according to the present invention, during the polishing process of the main surface of the substrate, the corner area in the vicinity of the four corners of the substrate where a very large force is applied among the end surfaces is mirror-polished, thereby reducing the incidence of glass chips. It is possible to greatly reduce the surface defect occurrence rate, and at the time of polishing the main surface of the substrate, the central area of the substrate with a relatively small force is used as a rough surface so that it can be handled. It is possible to provide a mask blank substrate that can be easily handled.
本発明に係るマスクブランク用基板の構造を示す側面図である。It is a side view which shows the structure of the board | substrate for mask blanks concerning this invention. 本発明に係るマスクブランク用基板の構造を示す上面図である。It is a top view which shows the structure of the board | substrate for mask blanks which concerns on this invention. 本発明に係るマスクブランク用基板の構造を示す側面の部分拡大図である。It is the elements on larger scale of the side which show the structure of the board | substrate for mask blanks which concerns on this invention. 端面を鏡面研磨する方法を説明するための図である。It is a figure for demonstrating the method of mirror-polishing an end surface. 本発明に係る主表面の研磨工程の概略を説明するための上面図である。It is a top view for demonstrating the outline of the grinding | polishing process of the main surface which concerns on this invention. 本発明に係る主表面の研磨工程の概略を説明するための側面図である。It is a side view for demonstrating the outline of the grinding | polishing process of the main surface which concerns on this invention. 大型マスクブランク用基板を示す斜視図である。It is a perspective view which shows the board | substrate for large sized mask blanks. ガラスチップの発生を説明するための図であり、主表面の研磨時（主表面右回転）の状態を示す上面図である。It is a figure for demonstrating generation | occurrence | production of a glass chip | tip, and is a top view which shows the state at the time of grinding | polishing of the main surface (main surface right rotation). ガラスチップの発生を説明するための図であり、主表面の研磨時（主表面左回転）の状態を示す上面図である。It is a figure for demonstrating generation | occurrence | production of a glass chip | tip, and is a top view which shows the state at the time of grinding | polishing of the main surface (main surface left rotation). ガラスチップの発生を説明するための図であり、主表面の研磨時における端面及びキャリアの側面図である。It is a figure for demonstrating generation | occurrence | production of a glass chip | tip, and is a side view of the end surface at the time of grinding | polishing of the main surface, and a carrier.
（実施の形態１）
　最初に、図１Ａ～図１Ｃ、図２を用いて、本発明に係るマスクブランク用基板の構造について説明する。図１は本発明に係るマスクブランク用基板の構造を示す図であり、図１Ａはマスクブランク用基板の側面図、図１Ｂは上面図、図１Ｃは側面の部分拡大図である。図１Ｃに示すように、本実施の形態に係るマスクブランク用基板１０は、表裏２つの主表面１１と、４つの端面Ｔとで構成される薄板であり、端面Ｔおよび主表面１１の間に面取り面Ｃを有する。図１Ｂに示すように、主表面１１は、一対の長辺Ｌ１（長辺Ｌ１の長さ：８００ｍｍ）と一対の短辺Ｌ２（短辺Ｌ２の長さ：５００ｍｍ）とを有する略矩形状である。図１Ａ、図１Ｃに示すように、端面Ｔは、端面同士が接する角部から主表面１１の辺方向に１００ｍｍ（辺Ｌ４の長さ：所定長さ）の範囲の角部側領域１３と、両角部側領域１３に挟まれる中央側領域１４とからなり、角部側領域１３の端面Ｔは表面粗さＲａが０．１ｎｍの鏡面であり、中央側領域１４は粗面である。 (Embodiment 1)
First, the structure of the mask blank substrate according to the present invention will be described with reference to FIGS. 1A to 1C and FIG. FIG. 1 is a view showing the structure of a mask blank substrate according to the present invention, FIG. 1A is a side view of the mask blank substrate, FIG. 1B is a top view, and FIG. 1C is a partially enlarged view of the side. As shown in FIG. 1C, the mask blank substrate 10 according to the present embodiment is a thin plate composed of two main surfaces 11 and four end surfaces T, and the end surface T and the main surface 11 are between them. It has a chamfered surface C. As shown in FIG. 1B, the main surface 11 has a substantially rectangular shape having a pair of long sides L1 (the length of the long side L1: 800 mm) and a pair of short sides L2 (the length of the short side L2: 500 mm). is there. As shown in FIGS. 1A and 1C, the end face T has a corner portion region 13 in a range of 100 mm (length of the side L4: a predetermined length) in a side direction of the main surface 11 from a corner portion where the end faces contact each other, The end surface T of the corner portion region 13 is a mirror surface having a surface roughness Ra of 0.1 nm, and the center portion region 14 is a rough surface.
　また、このマスクブランク用基板１０の側面１２は、面取り面Ｃと、両面取り面Ｃに挟まれる端面Ｔとを有する。また、端面Ｔは、一対の長辺（長辺Ｌ１または短辺Ｌ２）と一対の短辺Ｌ３（短辺Ｌ３の長さ：８．２ｍｍとを有する略矩形状である。なお、中央側領域１４は、基板を運搬するときに把持される領域とした。この状態を基板の上面から見ると、図１Ｂに示すように、基板の４つのコーナー部分（角部側領域１３に対応する部分）のみが鏡面研磨されていることになる。なお、中央側領域１４は表面粗さＲａが５０ｎｍの粗面とし、側面１２の長さ（基板の厚さ）は１０ｍｍとした。 The side surface 12 of the mask blank substrate 10 has a chamfered surface C and an end surface T sandwiched between the double-sided chamfered surfaces C. The end face T has a substantially rectangular shape having a pair of long sides (long side L1 or short side L2) and a pair of short sides L3 (length of short side L3: 8.2 mm). 14 is a region to be gripped when the substrate is transported, and when this state is viewed from the upper surface of the substrate, four corner portions (portions corresponding to the corner side region 13) of the substrate are shown in FIG. The central region 14 is a rough surface having a surface roughness Ra of 50 nm, and the length of the side surface 12 (substrate thickness) is 10 mm.
　本発明において、大型マスクブランク用基板１０とは、矩形基板または正方形基板の一辺（好ましくは各辺が）が５００ｍｍ以上のものをいう。大型マスクブランク用基板１０には、現状では、短辺Ｌ２×長辺Ｌ１が５００ｍｍ×８００ｍｍ～２１４０ｍｍ×２４６０ｍｍの範囲で様々なサイズがあり、厚さ（側面１２の長さ）が１０～１５ｍｍである。特に、基板の長辺Ｌ１の大きさが８００ｍｍ以上であると、端面の角部側領域に掛かる力が相当大きくなり、さらに１２００ｍｍ以上であると端面の角部側領域に掛かる力は非常に大きくなり、本願発明を適用することへの効果が非常に大きい。 In the present invention, the large mask blank substrate 10 is a substrate having one side (preferably each side) of 500 mm or more on a rectangular or square substrate. The large mask blank substrate 10 currently has various sizes in the range of 500 mm × 800 mm to 2140 mm × 2460 mm in the short side L2 × long side L1, and the thickness (the length of the side surface 12) is 10 to 15 mm. is there. In particular, when the size of the long side L1 of the substrate is 800 mm or more, the force applied to the corner side region of the end face is considerably large, and when it is 1200 mm or more, the force applied to the corner side region of the end face is very large. Thus, the effect of applying the present invention is very large.
　また、本発明において、所定の鏡面とは表面粗さＲａが０．５ｎｍ以下の面を、所定の粗面とは表面粗さＲａが５０ｎｍ以上の面をいう。 In the present invention, the predetermined mirror surface refers to a surface having a surface roughness Ra of 0.5 nm or less, and the predetermined rough surface refers to a surface having a surface roughness Ra of 50 nm or more.
　上記のとおり、本実施の形態は、端面Ｔを構成する角部側領域１３を表面粗さＲａ０．１ｎｍで鏡面研磨し、中央側領域１４を表面粗さＲａ５０ｎｍで粗面研磨したマスクブランク用基板１０の一例である。 As described above, in this embodiment, the corner side region 13 constituting the end face T is mirror-polished with a surface roughness Ra of 0.1 nm, and the central region 14 is rough-polished with a surface roughness Ra of 50 nm. 10 is an example.
　続いて、本実施の形態に係るマスクブランク用基板の製造方法について説明する。このマスクブランク用基板１０の製造方法における鏡面研磨工程では、端面を鏡面研磨する工程を実施した後、主表面を研磨する工程を実施する。 Subsequently, a method for manufacturing a mask blank substrate according to the present embodiment will be described. In the mirror polishing step in the method for manufacturing the mask blank substrate 10, after the step of mirror polishing the end surface, the step of polishing the main surface is performed.
　まず、図２を用いて、端面を鏡面研磨する工程について説明する。図２は、端面を鏡面研磨する方法を説明するための図である。同図に示すように、カップ型ブラシ２１を用いて角部側領域１３と（同図中、斜線部）を鏡面研磨する。これに限らず、角部側領域１３を鏡面研磨することができる研磨方法であれば、他のいかなる研磨方法を用いてもよい。 First, the process of mirror polishing the end face will be described with reference to FIG. FIG. 2 is a diagram for explaining a method of mirror polishing the end face. As shown in the figure, the corner side region 13 (in the figure, the hatched portion) is mirror-polished using a cup-type brush 21. However, the present invention is not limited to this, and any other polishing method may be used as long as the corner side region 13 can be mirror-polished.
　次に、図３Ａ、図３Ｂを用いて、主表面を鏡面研磨する工程について説明する。図３は、本発明に係る主表面の研磨工程の概略を説明するための図であり、図３Ａは上面図、図３Ｂは側面図を示している。同図に示すように、基板１０の端面Ｔをキャリア３１で保持し、基板１０を、上下に対向して設けられた上定盤３２の研磨面３４と下定盤３３の研磨面３５の間に、基板１０の両主表面１１が接するようにして挟持する。その後、上下定盤３２、３３を、上下定盤の研磨面３４、３５に対して垂直な上下定盤の垂直軸を回転軸Ｏ１、Ｏ２としてそれぞれ回転させるとともに、基板１０の自転軸Ｏ３を、下定盤の回転軸Ｏ２に対して平行に偏心し、かつ基板１０の一部が下定盤の回転軸Ｏ２上に位置するように定め、基板を、キャリア３１を回転させることで自転させる。上下定盤の研磨面３４、３５と基板の両主表面１１が互いに接触しつつ相対的に移動することにより、基板の両主表面１１は研磨される。研磨工程時に、基板１０の両主表面１１に掛かる圧力は１００ｇ／ｃｍ２とした。 Next, the process of mirror-polishing the main surface will be described with reference to FIGS. 3A and 3B. 3A and 3B are diagrams for explaining the outline of the main surface polishing step according to the present invention, in which FIG. 3A is a top view and FIG. 3B is a side view. As shown in the figure, the end surface T of the substrate 10 is held by a carrier 31, and the substrate 10 is placed between a polishing surface 34 of an upper surface plate 32 and a polishing surface 35 of a lower surface plate 33 provided so as to face each other vertically. The two main surfaces 11 of the substrate 10 are held in contact with each other. Thereafter, the upper and lower surface plates 32 and 33 are rotated with the vertical axes of the upper and lower surface plates perpendicular to the polishing surfaces 34 and 35 of the upper and lower surface plates as rotation axes O1 and O2, respectively, and the rotation axis O3 of the substrate 10 is rotated. The substrate 10 is determined to be eccentric in parallel to the rotation axis O2 of the lower surface plate and a part of the substrate 10 is positioned on the rotation axis O2 of the lower surface plate, and the substrate is rotated by rotating the carrier 31. The main surfaces 11 of the substrate are polished by the relative movement of the polishing surfaces 34 and 35 of the upper and lower surface plates and the main surfaces 11 of the substrate in contact with each other. During the polishing process, the pressure applied to both main surfaces 11 of the substrate 10 was 100 g / cm 2 .
　なお、このような主表面１１の研磨工程は複数回行われてもよく、それぞれ異なった内容の主表面１１の研磨工程を行ってもよい。例えば、硬質ポリッシャからなる研磨布を研磨面３４、３５に用いて第１の研磨工程を先に行い、その後、軟質ポリッシャからなる研磨布を研磨面３４、３５に用いて第２の研磨工程を行うものであってもよい。このように、主表面１１の研磨工程を複数回繰り返すことにより、より高い平坦度を有するマスクブランク用基板１０を製造することができ好ましい。
　研磨工程を終えた基板１０に対して、所定の洗浄工程を行った後、欠陥検査を行ったところ、基板主表面に表面欠陥が検出された基板の発生率が３％程度に低減でき、パーティクル検出の発生率も５％程度に低減でき、非常に高い歩留りとすることができた。 Such a polishing process of the main surface 11 may be performed a plurality of times, and the polishing process of the main surface 11 having different contents may be performed. For example, a polishing cloth made of hard polisher is used for the polishing surfaces 34 and 35 to perform the first polishing process first, and then a polishing cloth made of soft polisher is used for the polishing faces 34 and 35 to perform the second polishing process. You may do it. Thus, it is preferable that the mask blank substrate 10 having higher flatness can be manufactured by repeating the polishing process of the main surface 11 a plurality of times.
After performing a predetermined cleaning process on the substrate 10 after the polishing process, and performing a defect inspection, the generation rate of the substrate in which surface defects are detected on the main surface of the substrate can be reduced to about 3%. The detection rate could be reduced to about 5%, and the yield was very high.
　本実施の形態に係るマスクブランク用基板１０及びマスクブランク用基板１０の製造方法においては、端面Ｔの４隅側のみを鏡面研磨するから、ガラスチップの発生や脱落を防止することができ、またパーティクルの付着や脱落を防止することができる。その結果、マスクブランク用基板１０の研磨歩留まり、洗浄歩留まりを向上させることができる。 In the mask blank substrate 10 and the manufacturing method of the mask blank substrate 10 according to the present embodiment, since only the four corner sides of the end face T are mirror-polished, it is possible to prevent the generation and dropping of glass chips. It is possible to prevent adhesion and dropping of particles. As a result, the polishing yield and the cleaning yield of the mask blank substrate 10 can be improved.
　また、端面Ｔの中央側領域１４を粗面研磨することにより、以下の効果が得られる。
（１）基板の端面の鏡面研磨に掛かる加工時間を短縮することができる。
（２）人手によるハンドリングを行う場合、特に問題なく行うことができる。 Moreover, the following effects are acquired by carrying out rough surface grinding | polishing of the center side area | region 14 of the end surface T. FIG.
(1) The processing time required for mirror polishing of the end face of the substrate can be shortened.
(2) When handling manually, it can be done without any particular problem.
（実施の形態２）
　本実施の形態においては、長辺Ｌ１の長さを１２２０ｍｍ、短辺Ｌ２の長さを１４００ｍｍ、短辺Ｌ３の長さを１０．６ｍｍ、辺Ｌ４の長さを１５０ｍｍ、基板の厚さを１３ｍｍ、角部側領域１３の表面粗さＲａを０．０５ｎｍ、中央側領域１４の表面粗さＲａを５００ｎｍ（表面粗さＲａ５００ｎｍの表面は、目視では曇ったものとなる）、中央側領域１４は露光装置のマスクステージ５２に基板を載置したときにフォトマスクを検出するための検出光が照射される領域を含むものとした。また、ハンドリングは、人手ではなく機械を用いて行った。その他の構成、及び、マスクブランク用基板１０の製造方法については、上述した実施の形態１と同様のため、ここでは説明を省略する。
　研磨工程を終えた基板１０に対して、所定の洗浄工程を行った後、欠陥検査を行ったところ、基板主表面に表面欠陥が検出された基板の発生率が３％程度に低減でき、パーティクル検出の発生率も５％程度に低減でき、非常に高い歩留りとすることができた。 (Embodiment 2)
In the present embodiment, the length of the long side L1 is 1220 mm, the length of the short side L2 is 1400 mm, the length of the short side L3 is 10.6 mm, the length of the side L4 is 150 mm, and the thickness of the substrate is 13 mm. The surface roughness Ra of the corner side region 13 is 0.05 nm, the surface roughness Ra of the central side region 14 is 500 nm (the surface having a surface roughness Ra of 500 nm is cloudy by visual observation), and the central side region 14 is It includes an area irradiated with detection light for detecting the photomask when the substrate is placed on the mask stage 52 of the exposure apparatus. In addition, handling was performed using a machine instead of a human hand. Other configurations and the method for manufacturing the mask blank substrate 10 are the same as those in the first embodiment described above, and thus the description thereof is omitted here.
After performing a predetermined cleaning process on the substrate 10 after the polishing process, and performing a defect inspection, the generation rate of the substrate in which surface defects are detected on the main surface of the substrate can be reduced to about 3%. The detection rate could be reduced to about 5%, and the yield was very high.
　本実施の形態に係るマスクブランク用基板１０及びマスクブランク用基板１０の製造方法においても、上述した実施の形態１と同様の効果を得ることができる。 Also in the manufacturing method of the mask blank substrate 10 and the mask blank substrate 10 according to the present embodiment, the same effects as those of the first embodiment described above can be obtained.
（比較例１）
　本比較例においては、サイズが５００ｍｍ×８００ｍｍ、厚さが１０ｍｍのマスクブランク用基板１０の端面全面を表面粗さＲａ５０ｎｍの粗面とした。 (Comparative Example 1)
In this comparative example, the entire end face of the mask blank substrate 10 having a size of 500 mm × 800 mm and a thickness of 10 mm was a rough surface having a surface roughness Ra of 50 nm.
　その後、マスクブランク用基板１０の両主表面１１を上述した実施の形態と同様の研磨方法で鏡面研磨した。
　研磨工程を終えた基板１０に対して、所定の洗浄工程を行った後、欠陥検査を行ったところ、基板主表面に表面欠陥が検出された基板の発生率が２０％程度と高く、パーティクル検出の発生率も３０％程度と高く、低い歩留りとなってしまった。
　なお、ハンドリング用手袋を装着した手でハンドリングを試みたが、ハンドリング用手袋と大型マスクブランク用基板１０間で非常に滑りやすく危険であり、実用性に欠けることが判明した。 Thereafter, both main surfaces 11 of the mask blank substrate 10 were mirror-polished by the same polishing method as in the above-described embodiment.
After performing a predetermined cleaning process on the substrate 10 after the polishing process, a defect inspection was performed. As a result, the occurrence rate of the substrate on which surface defects were detected on the main surface of the substrate was as high as about 20%. The occurrence rate was as high as about 30%, resulting in a low yield.
Although handling was attempted with a hand wearing handling gloves, it was found that the handling gloves and the large mask blank substrate 10 were very slippery and dangerous, and lacked practicality.
（比較例２）
　本比較例においては、サイズが１２２０ｍｍ×１４００ｍｍ、厚さが１３ｍｍのマスクブランク用基板１０の端面全面を表面粗さＲａ１．０ｎｍの鏡面とした。 (Comparative Example 2)
In this comparative example, the entire end face of the mask blank substrate 10 having a size of 1220 mm × 1400 mm and a thickness of 13 mm was used as a mirror surface having a surface roughness Ra of 1.0 nm.
　その後、マスクブランク用基板１０の両主表面１１を上述した実施の形態と同様の研磨方法で鏡面研磨した。
　研磨工程を終えた基板１０に対して、所定の洗浄工程を行った後、欠陥検査を行ったところ、基板主表面に表面欠陥が検出された基板の発生率が３０％程度と高く、パーティクル検出の発生率も４０％程度と高く、低い歩留りとなってしまった。
　なお、ハンドリング用手袋を装着した手でハンドリングを試みたが、基板１０の重量が非常に重く、ハンドリング用手袋と大型マスクブランク用基板１０間で滑ってしまい、大型マスクブランク用基板１０を持つことができなかった。 Thereafter, both main surfaces 11 of the mask blank substrate 10 were mirror-polished by the same polishing method as in the above-described embodiment.
After performing a predetermined cleaning process on the substrate 10 that has finished the polishing process, a defect inspection was performed. As a result, the occurrence rate of the substrate in which surface defects were detected on the main surface of the substrate was as high as about 30%. The occurrence rate was as high as about 40%, resulting in a low yield.
Although handling was attempted with a hand wearing handling gloves, the weight of the substrate 10 is very heavy, and the substrate 10 has a large mask blank substrate 10 that slips between the handling gloves and the large mask blank substrate 10. I could not.
　なお、上述した実施の形態においては、中央側領域１４の全体を粗面としたが、比較的サイズの小さな大型マスクブランク用基板でハンドリングを行うための把持する領域が特定される場合においては、中央側領域１４のそれらの特定領域を除く領域の端面Ｔも角部側領域と同程度あるいはそれ以上の表面粗さの鏡面としてもよい。さらには、機械や治具を用いたハンドリングで基板を移動させる場合であって、前記の基板検出の関係で粗面とする必要がある中央側領域１４の特定領域が予め決定しているのであれば、基板の大きさに限らず、中央側領域１４のその粗面とする必要のある領域のみを前記表面粗さの粗面とし、それ以外の中央側領域１４を角部側領域と同程度あるいはそれ以上の表面粗さの鏡面とするようにしてもよい。また、中央側領域１４において、ガラスチップの発生率や研磨剤の固着に起因するパーティクルの発生率をより低減することを狙って、中央側領域１４の基板対称線から両側の角部側領域所定距離ごとに段階的に表面粗さを小さくしていく構成としてもよい。 In the above-described embodiment, the entire center side region 14 is a rough surface. However, in the case where a gripping region for handling with a relatively small large mask blank substrate is specified, The end surface T of the central region 14 excluding those specific regions may be a mirror surface having a surface roughness that is the same as or higher than that of the corner region. Furthermore, when the substrate is moved by handling using a machine or a jig, the specific region of the central region 14 that needs to be roughened in relation to the substrate detection is determined in advance. For example, not only the size of the substrate, but only the area that needs to be the rough surface of the central region 14 is the rough surface, and the other central region 14 is the same as the corner region. Or you may make it make it the mirror surface of the surface roughness more than that. Further, in the central side region 14, the corner side regions on both sides from the substrate symmetry line of the central side region 14 are predetermined in order to further reduce the generation rate of glass chips and the generation rate of particles caused by sticking of the abrasive. It is good also as a structure which makes surface roughness small in steps for every distance.
　また、マスクブランク用基板１０基板の形状は、矩形に限らず、主表面１１の一辺が５００ｍｍ以上の正方形であってもよい。 Further, the shape of the mask blank substrate 10 is not limited to a rectangle, and may be a square in which one side of the main surface 11 is 500 mm or more.
　なお、本発明は以上の実施の形態に限定されるものではなく、また、本発明の要旨を逸脱しない範囲において種々の変更が可能である。 It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

Claims (8)

  1. 　表裏２つの主表面と、４つの端面とで構成される薄板であり、前記端面および前記主表面の間に面取り面を有するマスクブランク用基板において、前記主表面は、一辺の長さが５００ｍｍ以上であり、前記端面は、隣接する端面が接する角部から主表面側の辺方向に所定長さの範囲の領域である２つの角部側領域と、当該２つの角部側領域に挟まれる中央側領域とからなり、前記角部側領域の端面の表面粗さＲａが０．５ｎｍ以下の鏡面であり、前記中央側領域が粗面であることを特徴とするマスクブランク用基板。 In the mask blank substrate having a chamfered surface between the end surface and the main surface, the main surface has a side length of 500 mm or more. And the end face is a center between two corner side areas which are areas having a predetermined length in a side direction on the main surface side from a corner where adjacent end faces are in contact with the two corner side areas. A mask blank substrate comprising a side region, a mirror surface having a surface roughness Ra of 0.5 nm or less on an end surface of the corner side region, and the center side region being a rough surface.
  2. 　前記中央側領域は、表面粗さＲａが５０ｎｍ以上の粗面であることを特徴とする請求項１に記載のマスクブランク用基板。 2. The mask blank substrate according to claim 1, wherein the central region is a rough surface having a surface roughness Ra of 50 nm or more.
  3. 　前記所定長さは、１００ｍｍ以上であることを特徴とする請求項１または２に記載のマスクブランク用基板。 3. The mask blank substrate according to claim 1, wherein the predetermined length is 100 mm or more.
  4. 　前記主表面の一辺の長さが１０００ｍｍ以上であり、前記所定長さが１５０ｍｍ以上であることを特徴とする請求項１または２に記載のマスクブランク用基板。 3. The mask blank substrate according to claim 1, wherein a length of one side of the main surface is 1000 mm or more, and the predetermined length is 150 mm or more.
  5. 　前記中央側領域は、基板を運搬するときに把持される領域を含むことを特徴とする請求項１から４のいずれか１項に記載のマスクブランク用基板。 The mask blank substrate according to any one of claims 1 to 4, wherein the central side region includes a region to be gripped when the substrate is transported.
  6. 　フラットパネルディスプレイのフォトマスクブランクを製造する際に用いられることを特徴とする請求項１乃至４のいずれか１項に記載のマスクブランク用基板。 The mask blank substrate according to any one of claims 1 to 4, wherein the mask blank substrate is used when manufacturing a photomask blank for a flat panel display.
  7. 　請求項１乃至５のいずれか１項に記載のマスクブランク用基板の主表面に、薄膜を有することを特徴とするマスクブランク。 A mask blank comprising a thin film on the main surface of the mask blank substrate according to any one of claims 1 to 5.
  8. 　請求項１乃至５のいずれか１項に記載のマスクブランク用基板の主表面に、薄膜パターンを有することを特徴とするフォトマスク。 A photomask having a thin film pattern on a main surface of the mask blank substrate according to any one of claims 1 to 5.
PCT/JP2010/051842 2009-02-13 2010-02-09 Substrate for mask blank use, mask blank, and photo mask WO2010092937A1 (en)

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MY154175A (en) 2015-05-15
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