JP2012190044A - Mask blanks and method for manufacturing mask blanks - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately form a marker on a mask blanks.SOLUTION: A mask blanks 10 is formed of a glass substrate 12 and a mask pattern thin film 14 formed on the glass substrate 12. The glass substrate 12 is formed on a mirror-like surface by irradiation of laser light, and includes a recessed part 20 used as a marker 18. The recessed part 20 is formed, in the glass substrate 12 on an end face orthogonal to the main surface in which the thin film to be a transfer pattern is formed, on an area trimmed by 1.2 mm from both sides of the main surface and an area within 10 mm from the four corners of the glass substrate 12. The marker 18 represents unique identification information, identification symbol, or management symbol of the mask blanks 10.

Description

  The present invention relates to a mask blank glass substrate manufacturing method, a mask blank manufacturing method, a mask blank glass substrate, and a mask blank.

2. Description of the Related Art Conventionally, there has been known a mask blank in which an optical reading type area code is provided on a metal film formed on an end surface or a back surface of a glass substrate (for example, see Patent Document 1). Moreover, the mask blanks by which the predetermined symbol was marked in the frosted part of the glass substrate side surface (end surface) are known (for example, refer patent document 2).
JP 2002-116533 A JP 59-15938 A

  In recent years, the wavelength of an exposure light source has been shortened to 200 nm or less, and the quality required for a glass substrate for mask blanks and mask blanks (for example, the size and number of allowable defects that affect device pattern characteristics, resist, The in-plane film thickness uniformity of the film is becoming increasingly severe. Depending on how the area code or the like is formed, dust may be generated in a later process, which may make it difficult to satisfy the required quality. In addition, depending on how the area code or the like is formed and the position where it is formed, the in-plane film thickness uniformity of the resist film formed by the spin coating method may deteriorate, making it difficult to satisfy the required quality. In particular, in the case of a thin resist film having a thickness of 300 nm or less in recent years due to the miniaturization of the pattern, the problem at the time of pattern formation due to the variation in the in-plane film thickness becomes larger than before, and the problem becomes remarkable. Further, in the recent glass substrate for mask blanks, the end surface may be mirror-polished, and there is a possibility that sufficient reading accuracy cannot be obtained with a glossy symbol or the like.

  Then, an object of this invention is to provide the manufacturing method of the glass substrate for mask blanks, the manufacturing method of a mask blank, the glass substrate for mask blanks, and mask blanks which can solve said subject.

In order to solve the above problems, the present invention has the following configuration.
(Configuration 1) A method for manufacturing a glass substrate for mask blanks, wherein the glass substrate surface is a region that does not affect the transfer on the surface of the glass substrate and is irradiated with laser light on a mirror-like surface. A marking step is provided for forming a recess used as a marker for identifying or managing the device. In the marking process, for example, the marker is a main surface of the glass substrate main surface on the side where the thin film for mask pattern is not formed, a peripheral region that does not affect transfer, a side surface of the glass substrate that does not affect transfer, and the main surface. It is formed on a chamfered surface provided between the surface and the side surface, a notch mark on a glass substrate, or the like. In the marking process, for example, a concave portion is formed by melting or sublimating a mirror-like surface by laser irradiation. The marker thus formed has sufficient reading accuracy and there is no risk of dust generation in a later process.

  This marker can be used, for example, as identification information / identification symbol (identification code) or management symbol (management code) unique to the mask blank glass substrate to be manufactured. In this way, single wafer management of the glass substrate for mask blanks, which has not been possible in the past, becomes possible.

  The identification information includes, for example, information acquired during the manufacturing process (substrate information) (defect information, surface shape information such as surface roughness and flatness, shape such as plate thickness (thickness) and size, etc.) It can be associated with specific substrate information (material, component, composition, purity, birefringence, transmittance, etc.) possessed by the glass substrate. In this way, it is possible to reliably associate the acquired or prepared information with the glass substrate for mask blanks.

  In the marking process, in place of the marker indicating the identification information / identification symbol or management symbol, or in addition to the marker indicating the identification information / identification symbol or management symbol, the substrate information acquired during the manufacturing process or a unique substrate of the glass substrate You may form the marker which shows information etc. directly. Also in this case, the single wafer management of the glass substrate for mask blanks can be performed appropriately.

Here, examples of the material of the glass substrate include synthetic quartz glass and SiO ₂ —TiO ₂ multicomponent glass. Depending on the material of the glass substrate, the wavelength of the laser beam for forming a recess by melting or sublimating by laser beam irradiation is selected. In the case of the glass substrate material as described above, in the marking process, for example, a marker can be formed by a laser marker using a carbon dioxide (CO ₂ ) gas laser. By appropriately adjusting the energy of the laser beam, a part of the surface of the glass substrate can be appropriately melted or sublimated, and the recess formed by melting or sublimating can be read with high accuracy. And generation | occurrence | production of the crack by aged deterioration can also be suppressed. Moreover, a marking process can also form a several recessed part by irradiating a laser beam in multiple times to the position which should become each recessed part. In this way, variation in the shape of the plurality of recesses can be reduced. Therefore, the marker reading accuracy can be improved. Each of the plurality of recesses may constitute each point of a two-dimensional code such as a data matrix or a QR code, or a hidden code or random number for preventing a third party from knowing the marker information. It may be a code.

  If an appropriate wavelength selection of the laser beam according to the material of the glass substrate is not performed, for example, a scratched marker is formed in the portion irradiated with the laser beam. In this case, scratch-like markers cause dust generation, which is not preferable.

  In addition, by forming the marker on the side surface of the glass substrate, an end face such as a chamfered surface, or a notch mark, a new mask pattern thin film formed on the main surface of the glass substrate or on the main surface by forming the marker. It is possible to prevent the occurrence of various defects. Furthermore, since the marker can be erased by end face polishing or the like, for example, even when it is necessary to replace the marker, a new marker can be formed without reducing the thickness of the glass substrate.

  The marking step is performed, for example, before grinding / polishing of the glass substrate at the time of receiving the glass substrate or after performing grinding / polishing and substrate inspection. The marking step may be performed during each stage of grinding / polishing, for example, after grinding of the glass substrate, after polishing of the end surface of the glass substrate, or after mirror polishing of the main surface of the glass substrate. When the marking process is performed before the substrate inspection, for example, a marker indicating identification information / identification symbol or management symbol of the glass substrate is formed.

  In addition, for example, when performing precision polishing and ultraprecision polishing in end face polishing of a glass substrate, the marking step may be performed between precision polishing and ultraprecision polishing for the end face. In this way, the surface roughness of the inside of the marker and the end face other than the marker can be reduced, and it is more effective in preventing the generation of dust. Precision polishing is polishing performed using, for example, a polishing liquid containing cerium oxide and a solvent such as water, and a polishing brush or polishing pad. The ultra-precision polishing is polishing performed using, for example, a polishing liquid containing colloidal silica and a solvent such as water, and a polishing brush or a polishing pad. You may perform a marking process between precision grinding | polishing and ultraprecision grinding | polishing to the glass substrate main surface, for example. In this case, since the ultra-precision polishing of the main surface is performed after the marker is formed in this case, the possibility that the marker may cause dust generation can be further reduced.

(Configuration 2) The method further includes a step of preparing substrate information related to the glass substrate, and associates the substrate information related to the glass substrate with the marker.
In this way, substrate information such as information on the surface shape, flatness, and defects of the glass substrate can be directly associated with the glass substrate.

The preparation of the substrate information related to the glass substrate means preparing the substrate information acquired during the manufacturing process and the unique substrate information possessed by each glass substrate. For example, the board information acquired in the manufacturing process includes board information obtained in the board inspection process.
The substrate inspection step inspects the shape of the main surface of the glass substrate, for example, thickness, surface shape (warp shape of the main surface, unevenness of the entire main surface), flatness, parallelism, and the like. If it does in this way, the film-forming process etc. which form the thin film for mask patterns (for example, a phase shift film, a light shielding film, etc.) can be efficiently performed at the time of manufacture of mask blanks.

  Further, the substrate inspection step inspects the position, type (convex defect (particles, etc.), concave defects (pinholes, scratches, etc.), size), size, etc., of the defects on the main surface of the glass substrate. If such defect data is known, for example, a mask pattern can be designed while avoiding defects during mask manufacturing.

(Configuration 3) The substrate information related to the glass substrate is information including at least one of physical characteristics, chemical characteristics, optical characteristics, surface morphology, shape, material, and defects of the glass substrate. . Examples of the physical characteristics of the glass substrate include birefringence, refractive index, absorption coefficient, and the like. Moreover, acid resistance, alkali resistance, etc. are mentioned as a chemical characteristic of a glass substrate. Examples of the optical characteristics of the glass substrate include an absorption coefficient and transmittance. Examples of the surface form of the glass substrate surface include surface roughness, waviness, flatness, parallelism, convex shape, and concave shape. Examples of the shape of the glass substrate include thickness (plate thickness) and size. Examples of the material for the glass substrate include glass type and composition. Examples of defects in the glass substrate include defects inside the substrate such as striae, bubbles, and abnormal transmittance due to impurities, and defects on the substrate surface such as particles, scratches, and pinholes. In addition, as described above, with respect to defects in the glass substrate, in addition to the types described above, by adding information such as the position and size of the defect in the glass substrate, a mask pattern is designed to avoid the defect, for example, at the time of mask manufacturing. It can be dealt with by applying to mask blanks that can be used or in a relatively long wavelength range, or a grade that does not cause defects.

(Configuration 4) A mask pattern thin film to be a mask pattern is formed on the main surface of the mask blank glass substrate obtained by the method for manufacturing a mask blank glass substrate according to any one of configurations 1 to 3. A film forming step is provided.

  A plurality of grades (grades) having different qualities exist depending on the exposure wavelength and application (formation pattern). Depending on the grade, the allowable defect size, number, etc. vary. In addition, there are a plurality of types of mask pattern thin films (phase shift films, light shielding films, etc.) and resist films that are formed when the mask blanks are manufactured. Therefore, it is not easy to manage the grade and the types of thin films and resist films to be formed at the time of manufacturing mask blanks.

  However, when the configuration 4 is adopted, mask blanks can be managed individually. Therefore, when manufacturing mask blanks, it is possible to appropriately manage the grades and types of thin films and resist films to be formed. The marker indicates, for example, identification information / identification symbol or management symbol of the glass substrate for mask blanks. This identification information / identification symbol or management symbol is associated with, for example, the type of mask blank manufactured by the glass substrate for mask blank. Further, since the mask blanks can be reliably managed, for example, when information on the mask blanks is supplied to the mask manufacturer together with the mask blanks, this information can be reliably associated with the mask blanks. .

(Structure 5) A mask blank manufacturing method including a film forming step of forming a mask pattern thin film to be a mask pattern on a main surface of a glass substrate, wherein the region does not affect the transfer on the glass substrate surface. A marker for identifying or managing mask blanks in which a mask pattern thin film to be a mask pattern is formed on the glass substrate and / or the glass substrate by irradiating a mirror surface with laser light. The manufacturing method of the mask blank characterized by further providing the process of forming the recessed part used as.

  In the case of the configuration 5, the same effect as the configuration 4 can be obtained. The marking process in the configuration 5 may be performed in the manufacturing process of the glass substrate as in the configuration 1 to the configuration 3, but after the manufacturing process of the glass substrate, before the mask pattern thin film is formed, or You can go later.

(Configuration 6) The method further includes a step of preparing substrate information related to the glass substrate before the film forming step, wherein the marker is associated with the substrate information related to the glass substrate and based on the substrate information read from the marker The method further comprises a thin film determination step for determining the mask pattern thin film to be formed, wherein the film formation step forms the mask pattern thin film determined in the thin film determination step.

  In this way, the type of mask pattern thin film to be formed in the film forming process can be changed, for example, by the substrate information in the process of preparing the substrate information (specifically, the inspection result of the substrate inspection process (the main surface of the glass substrate It can be determined according to the substrate inspection step)) for inspecting at least one of the surface shape, flatness, and defects. Therefore, the glass substrate for mask blanks can be used effectively without waste.

  A thin film determination process identifies the surface shape of a main surface as a shape which is one of the board | substrate information of the glass substrate for mask blanks, for example. When the surface shape of the main surface is concave and convex, when the film stress is present in the mask pattern thin film, the surface shape when the mask blank is formed changes. Therefore, the thin film determination step determines the type and film thickness of the mask pattern thin film to be formed in consideration of the inspection result of the substrate inspection step. In this way, for example, the yield can be improved as compared with the case where the type of the mask pattern thin film to be formed in the film forming step is determined in advance.

(Structure 7) After the film forming step, a thin film information preparing step of preparing thin film information on the mask pattern thin film is further provided, and the marker is associated with the thin film information obtained in the thin film information preparing step. Specifically, the thin film information preparation step refers to, for example, a thin film inspection step of inspecting at least one of thin film information of the mask pattern thin film, for example, optical characteristics, surface shape of the thin film, and defects. If it does in this way, the optical characteristics which are the thin film information of the thin film for mask patterns, the thin film information regarding the surface shape of a thin film, a defect, etc. can be matched directly with a mask blank.

(Structure 8) The thin film information includes at least one of physical properties, chemical properties, electrical properties, optical properties, surface morphology of the thin film surface, materials, defects, and film forming conditions. It is. Examples of the physical characteristics of the thin film include a thermal expansion coefficient. Further, the chemical properties of the thin film include acid resistance, alkali resistance, water resistance, and the like. The electrical characteristics of the thin film include resistivity. Examples of the surface form of the thin film surface include surface roughness, waviness, flatness, parallelism, convex shape, and concave shape. Examples of the material for the thin film include components, composition, composition distribution in the film thickness direction and in-plane direction, and the like. As defects of the thin film, there may be an abnormality in transmittance due to mixing of impurities and defects such as particles and pinholes. Examples of film forming conditions include a film forming apparatus, a gas type, a gas pressure, sputtering target information, a gas flow rate, a heating condition, and a film forming date. In addition to the above-mentioned types of defects, in addition to the types of defects described above, information such as the position and size of defects in the thin film is added, so that, for example, mask patterns can be designed to avoid defects during mask manufacturing. It is possible to cope with this problem by applying it to mask blanks used for grades where defects can not be a problem.

  In addition, as the usage of the thin film information, the following usage is specifically considered. The marking step forms the marker for identifying the thickness of the mask blank glass substrate, and the mask blank manufacturing method is thin film information of the mask pattern thin film. For example, optical characteristics, thin film surface It has a thin film inspection process for inspecting at least one of shape and defect, and the thin film inspection process includes a pass / fail determination process for determining whether or not the mask blanks specifications are met, and it is determined that the mask blanks specifications are not met A thin film peeling step for peeling the mask pattern thin film from the mask blank, and information obtained by reading the thickness of the mask blank glass substrate from which the mask pattern thin film was peeled in the thin film peeling step from the marker. The thickness identifying step that is identified by using the polishing amount according to the thickness identified in the thickness identifying step A re-polishing step of polishing the main surface of the glass substrate for scuff blanks, and the film forming step includes a new mask pattern on the main surface of the glass substrate for mask blanks polished in the re-polishing step. A thin film is formed.

Examples of the material for the mask blank glass substrate include synthetic quartz glass and SiO ₂ —TiO ₂ multi-component glass. Since such glass is expensive, it is desired to use the glass substrate effectively without waste. If it does as mentioned above, the film formation defect etc. of the thin film for mask patterns will arise, and even if it determines with not meeting the specification of mask blanks, the reproduction | regeneration (recycling) of the glass substrate for mask blanks can be performed efficiently. . Moreover, new mask blanks can be appropriately manufactured using the regenerated glass substrate for mask blanks. In addition, the glass substrate for mask blanks may be reproduced | regenerated to the glass substrate for mask blanks of the grade different from before reproduction | regeneration, for example.

  Moreover, when it does as mentioned above, since the thickness of a glass substrate can be selected in a thickness identification process, the thickness division process before re-polishing can be simplified. Furthermore, polishing conditions such as the polishing amount can be easily and appropriately set according to the selected thickness. In the re-polishing step, for example, by setting an extra amount according to the thickness, polishing is performed by the polishing amount according to the thickness. After the re-polishing step, for example, a marker for identifying the regenerated glass substrate for mask blanks is formed. In addition, the marker of the glass substrate for mask blanks before reproduction | regeneration can be erase | eliminated by grinding | polishing by a re-grinding process, for example.

(Structure 9) A resist film forming step for forming a resist film on the mask pattern thin film after the film forming step, and a resist film information for preparing resist film information relating to the resist film after the resist film forming step A preparation step, wherein the marker is associated with the resist film information obtained in the resist film information preparation step. In the case of the configuration 9, the same effect as the configurations 4 and 5 can be obtained. The resist film information preparation step specifically refers to, for example, a resist film inspection step for inspecting a resist film.

(Configuration 10) The resist film information is information including at least one of physical characteristics, chemical characteristics, surface morphology of the resist film surface, material, defects, and formation conditions. Examples of physical characteristics of the resist film include hardness. The chemical properties of the resist film include acid resistance and base resistance. Examples of the surface form of the resist film surface include surface roughness, waviness, flatness, in-plane film thickness uniformity, average film thickness, and a bird's eye view of the resist film thickness. Examples of the material for the resist film include a resin material, molecular weight, and resist type. Examples of defects in the resist film include convex defects such as particles and concave defects such as pinholes. For resist film defects, in addition to the types described above, by adding information such as the position and size of the defect in the resist film, it is possible to design a mask pattern while avoiding the defect, for example, during mask manufacturing. Or by applying it to mask blanks used in grades where defects do not cause problems. Examples of the resist film forming conditions include a coating apparatus, a coating rotation condition, a heating condition, a heating apparatus, a cooling condition, a cooling apparatus, a resist film formation date, and a resist film forming environment.

  Further, as usage of resist film information, the following usage can be considered. The marking step forms the marker for identifying a resist film to be formed on the mask pattern thin film, and the mask blank manufacturing method includes forming a resist film on the mask pattern thin film. For example, a resist film inspection process for inspecting at least one of in-plane film thickness uniformity and defects, which is resist film information of the formed resist film, and whether or not the mask blanks specifications are met. A resist film inspection process including a pass / fail determination process, a resist film peeling process for peeling the resist film from the mask blank glass substrate determined not to meet the mask blank specifications, and the resist film peeling process The resist film to be formed on the mask pattern thin film from which the resist film has been peeled off is removed from the marker. Further comprising a registration identification step of identifying by using only took information, the resist film which has been identified by the resist identifying step, and a resist film reshaping step of forming on said thin film for mask pattern.

  In this way, the resist film can be appropriately reapplied and formed even when the application of the resist film fails, for example. In addition, since the resist film to be re-formed is reliably identified, process management can be simplified.

(Configuration 11) A new mask blank is prepared using a mask blank that has been manufactured on a glass substrate for a mask blank and has a mask pattern thin film to be a mask pattern and a resist film formed on the mask pattern thin film. A method for manufacturing a mask blank to be manufactured, wherein the glass substrate for mask blank is a region that does not affect transfer on the surface of the glass substrate, and is formed on a mirror-like surface by irradiation with laser light. A marker for identifying or managing a glass substrate and / or mask blanks is formed, and the marker includes substrate information of the glass substrate, thin film information of the mask pattern thin film, and resist film information of the resist film. The manufactured mask blank is associated with information including at least one of the mask blanks and the manufactured mask blank. A film peeling process for peeling the resist film or the resist film and the mask pattern thin film, and a film re-forming process for forming a resist film different from the peeled film, or a mask pattern thin film and a resist film And acquiring at least one of resist film information on the resist film formed in the film re-forming step or thin film information on the mask pattern thin film, and at least one of the acquired resist film information or the thin film information Is associated with the marker. Specifically, the film peeling step refers to, for example, a resist film peeling step or a thin film peeling step.

  Furthermore, on a mask blank glass substrate, a mask pattern thin film that becomes a mask pattern, a resist film formed on the mask pattern thin film, and a marker or mask pattern for identifying the resist film A mask blank manufacturing method for manufacturing a new mask blank using a manufactured mask blank provided with a marker for identifying a thin film or a marker for identifying a glass substrate, wherein the manufactured mask blank is A resist film to be formed on the manufactured mask blank is selected by using a preparation process to prepare, a resist film peeling process for peeling the resist film of the manufactured mask blank, and information read from the marker. Resist film selection process and before selected in the resist film selection process A preparatory step of preparing the manufactured mask blanks comprising a resist film re-forming step of forming a resist film on the mask pattern thin film; and a resist film peeling for stripping the resist film of the manufactured mask blanks And using the information read from the marker, a resist film selection step for selecting a resist film to be formed on the manufactured mask blanks, and the resist film selected in the resist film selection step And a resist film re-forming step formed on the pattern thin film.

  In this way, even when a sensitivity change (deterioration or the like) occurs in the resist film of the manufactured mask blank, the mask blank can be efficiently reproduced. Further, since the marker is formed on the mask blank itself, the information about the mask blank and the mask blank can be associated with each other with certainty. This also simplifies process management.

(Configuration 12) The marker has a concave shape formed by irradiating a mirror surface with a laser beam, which is a region that does not affect the transfer on the surface of the glass substrate. In this way, it is possible to form a marker that is less likely to generate dust.

(Structure 13) The resist film is a chemically amplified resist film, and as the manufactured mask blank, a mask blank having a predetermined period after the resist film is applied is prepared. In this way, mask blanks using a chemically amplified resist film in which the sensitivity change of the resist film is fast can be appropriately reproduced. In the chemically amplified resist film, for example, the sensitivity change may increase in a short period of about 2 weeks. If a mask is manufactured using a mask blank on which a resist film having a large sensitivity change is formed, CD variation in the formed mask pattern is increased, which is not preferable. In the case of a normal resist film, the period until the sensitivity change becomes large is, for example, about one month or three months.

(Configuration 14) A glass substrate for mask blanks, which is a region that does not affect transfer on the surface of the glass substrate, and is formed on a mirror-like surface by irradiation with laser light and / or the glass substrate. A concave portion used as a marker for identifying or managing mask blanks in which a mask pattern thin film to be a mask pattern is formed on a glass substrate is provided. In this way, the same effect as in Configuration 1 can be obtained.

(Structure 15) The concave portion is formed in a region outside the optical path of the inspection light for inspecting at least a defect existing in the pattern formation region on the end surface orthogonal to the main surface on which the mask pattern thin film is formed on the glass substrate surface. The As described above, since the concave portion is formed at a region outside the optical path of the inspection light for inspecting the defect existing at least in the pattern formation region on the end face, the concave portion does not interfere with the inspection light, and the defect quality is guaranteed. The mask blank glass substrate and mask blanks thus obtained are obtained.

(Configuration 16) A glass substrate for mask blanks, which is a region excluding 1.2 mm from both sides of the main surface at an end surface orthogonal to the main surface on which a thin film to be a transfer pattern on the glass substrate surface is formed. In addition, in the region within 10 mm from the four corners of the glass substrate, the glass substrate formed by laser light irradiation and / or mask blanks in which a mask pattern thin film serving as a mask pattern is formed on the glass substrate are identified. Or a recess used as a marker for management. In this way, the same effects as those of Configuration 1 and Configuration 15 can be obtained. Furthermore, in the case of forming a resist film on the mask pattern thin film by a spin coating method, it is possible to prevent the in-plane film thickness uniformity of the resist film from being deteriorated due to the recesses formed on the end face.

(Configuration 17) The opening width (L1) of the recess is 150 μm or more, the depth (D) of the recess is 10 μm or more, and the ratio of the opening width to the depth of the recess (L1 / D) is 10 or more. In this way, sufficient reading accuracy can be ensured, and furthermore, the inside of the recess can be easily cleaned with an end face brush or the like, so that dust generation can be suppressed.

  The surface roughness of the concave portion is preferably a surface roughness different from the mirror-like surface to be formed, for example, an arithmetic average surface roughness Ra in the range of 0.1 to 5 nm, more preferably 0.1 to 2 nm. It is preferable to set by. Arithmetic mean surface roughness Ra is in accordance with Japanese Industrial Standard (JIS) B0601. Specifically, the surface roughness of the recess is the surface roughness of the bottom of the recess.

  Moreover, the annular convex part surrounding this recessed part may be formed in the periphery of the opening part of the said recessed part. If comprised in this way, the reading precision of a marker can be improved. Therefore, for example, even when the depth of the recess is shallow, the marker can be read with sufficient accuracy. When the depth of the recess is shallow, the amount of polishing necessary for erasing the marker is reduced. Therefore, if comprised in this way, when reproducing | regenerating the glass substrate for mask blanks, for example, replacement | exchange of a marker will become easy. The annular convex portion is preferably formed so as to rise smoothly. The height of the convex portion is preferably 0.05 μm to 5 μm, more preferably 0.05 μm to 1 μm.

(Configuration 18) The marker is associated with substrate information regarding the glass substrate. In this way, the same effect as in Configuration 1 can be obtained.

(Configuration 19) Mask blanks, comprising: the mask blank glass substrate according to any one of configurations 14 to 18; and a mask pattern thin film that is formed on the mask blank glass substrate and serves as a mask pattern. Prepare. If comprised in this way, the effect similar to the structures 3 and 4 can be acquired.

(Configuration 20) The marker corresponds to at least any one of substrate information about the glass substrate, thin film information about the mask pattern thin film, and resist film information about a resist film formed on the mask pattern thin film. Attached. In this way, the same effects as those of configurations 2, 7, and 9 can be obtained.

  Markers that are less likely to generate dust can be formed on the glass substrate for mask blanks. In addition, it is possible to efficiently regenerate the mask blank glass substrate and the mask blank. Moreover, the glass substrate for mask blanks and mask blanks with which defect quality was ensured are obtained. In addition, when a resist film is formed on a mask pattern thin film by a spin coating method, a mask blank glass substrate and a mask blank are obtained in which deterioration of in-plane uniformity of the resist film due to a marker formed on the end face is prevented. .

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 shows an example of the configuration of a mask blank 10 according to an embodiment of the present invention. FIG. 1A is a side view of the mask blank 10. In this example, the mask blank 10 is a mask blank for an exposure light source having a wavelength of 200 nm or less, such as an ArF excimer laser (wavelength 193 nm) or an F ₂ excimer laser (wavelength 157 nm). 14 and a resist film 16.

  The glass substrate 12 is a glass substrate for mask blanks, and the substrate material is made of, for example, synthetic quartz glass. The main surface and end surface (side surface, chamfered surface) of the glass substrate 12 are polished to a predetermined surface roughness so as to be a mirror surface (for example, 1 nm or less in arithmetic average surface roughness Ra). Moreover, in this example, the glass substrate 12 has the marker 18 for identifying or managing the glass substrate 12 in a part of end surface. By using the marker 18, the glass substrate 12 and the mask blanks 10 are managed as a single wafer.

  The mask pattern thin film 14 is a thin film such as a light shielding film or a phase shift film. The mask pattern thin film 14 is patterned in the mask manufacturing process to form a mask pattern. The resist film 16 is formed on the mask pattern thin film 14.

  FIG. 1B shows an example of the configuration of the marker 18. In this example, the marker 18 is a two-dimensional code, and has a plurality of recesses 20 that constitute each point of the two-dimensional code. Each recess 20 is formed by melting or sublimating a part of the end surface of the glass substrate 12 by irradiation with laser light.

  In this example, the marker 18 indicates identification information unique to the glass substrate 12. Further, this identification information is associated with information acquired in the manufacturing process regarding the surface shape, flatness, defects, and the like in the manufacturing process of the mask blank 10.

FIG. 2 shows an example of the detailed shape of the recess 20. In this example, the recess 20 is a hole formed by a laser marker using a carbon dioxide (CO ₂ ) gas laser. The opening of the recess 20 is substantially circular. Further, an annular convex portion is formed on the periphery of the opening portion of the concave portion 20 so as to swell smoothly from the end surface of the glass substrate 12 so as to surround the opening portion of the concave portion 20. By forming the opening in this manner, the reading accuracy of the marker 18 (see FIG. 1) can be improved. The opening of the recess 20 may have a polygonal shape such as a quadrilateral shape, or a shape with rounded corners of the polygon.

  Here, the opening width L1 of the recess 20 is, for example, about 100 to 500 μm, more preferably about 150 to 300 μm. The width L2 of the bottom part of the recessed part 20 is 10-450 micrometers, for example, More preferably, it is about 30-250 micrometers. The width L3 of the inclined portion of the recess 20 is, for example, about 5 to 75 μm, more preferably about 15 to 60 μm. The depth D of the recessed part 20 is 3-20 micrometers, for example, More preferably, it is about 5-15 micrometers. The raised height of the opening of the recess 20 is, for example, about 0.05 to 5 μm, and more preferably about 0.05 to 1 μm. Moreover, the surface roughness of the recessed part 20 is 0.1-5 nm by arithmetic mean surface roughness Ra, for example, More preferably, it is 0.1-2 nm.

  Sufficient reading accuracy can be secured, and further, the inside of the recess can be easily cleaned with an end face brush or the like, and in order to suppress dust generation, the opening width L1 of the recess 20 is 150 μm or more, and the depth D of the recess 20 is 10 μm or more. The ratio of the opening width to the depth of the recess (L1 / D) is preferably 10 or more.

  In addition, the glass substrate 12 is checked for the presence or absence of convex defects (particles, etc.), concave defects (pinholes, scratches, etc.), striae, bubbles, and abnormal transmittance due to contamination in at least the region where the mask pattern is formed. Defect inspection is performed. For example, inspecting the convex defect or concave defect on the surface of the glass substrate 12, striae inside the glass substrate 12, and the presence or absence of bubbles is performed by, for example, an inspection method described in Japanese Patent No. 3422935. In this inspection method, the inspection light (laser light) propagates through the glass substrate 12 satisfying the total reflection condition on both main surfaces of the glass substrate 12 and at least one set of side surfaces orthogonal to the main surface. Inspection light (laser light) is introduced from a chamfered surface sandwiched between the main surface and side surfaces, and leakage light that leaks inspection light (laser light) due to deviation from total reflection conditions due to convex or concave defects is detected. By doing so, the presence or absence of the defect is inspected. On the other hand, in order to inspect whether there is an abnormality in transmittance due to impurities mixed in the glass substrate 12, light having an exposure wavelength is introduced from the side surface of the glass substrate 12, and internal defects of the glass substrate are generated by the light having the introduced exposure wavelength. Light having a wavelength longer than the exposure wavelength is received, and internal defects are inspected based on the amount of the received light. In any of the above inspection methods, the inspection light strikes the side surface of the glass substrate 12. Therefore, if a concave portion as a marker is formed on the side surface of the glass substrate 12 where the inspection light hits, defect inspection cannot be performed, or even if it can be performed, sufficient inspection accuracy cannot be obtained. The formation position of the concave portion as the marker is formed in a region outside the optical path of the inspection light for inspecting at least a defect existing in the pattern formation region on the side surface which is an end surface orthogonal to the main surface on which the mask pattern thin film is formed. It is preferable. Specifically, in the glass substrate 12 having a size of 152.4 mm × 152.4 mm × 6.35 mm, a position outside the center 132 mm on the side surface of the glass substrate 12 (region within 10 mm from the corners of the four corners of the glass substrate). It is preferable to form a recess as a marker.

  More preferably, it is desirable to form a recess as a marker in a region excluding 1.2 mm from both sides of the main surface of the glass substrate 12 and within 10 mm from the four corners of the glass substrate. By forming a concave portion as a marker at the above specific position, in-plane film thickness uniformity of the resist film on the mask pattern thin film deteriorates when the resist film is formed on the mask pattern thin film by the spin coating method. Can be prevented.

  FIG. 3 is a flowchart showing an example of a method for manufacturing the mask blank 10. Except for the points described below, each step is the same as or similar to each step in the known method for manufacturing mask blanks 10. In this example, first, grinding is performed by a double-sided lapping device for the glass substrate 12 whose end face is chamfered (grinding step S102).

  Next, the end surface and the main surface of the glass substrate 12 are polished by the double-side polishing apparatus (polishing step S104) and cleaned after polishing (cleaning step S106). In the polishing step S104, for example, rough polishing, precision polishing, and ultra-precision polishing are performed on the end surface and the main surface of the glass substrate 12 to finish a mirror surface having a root mean square roughness RMS of 0.2 nm or less.

  Next, substrate inspection is performed to obtain information on the surface shape, flatness, and defects of the glass substrate 12 (substrate inspection step S108). The substrate inspection step S108, for example, inspects the surface shape of the glass substrate 12, for example, the thickness, flatness, warpage shape of the main surface (unevenness of the entire main surface), and the like. Moreover, about the defect of the glass substrate 12, the position of a defect, a kind, size, etc. are test | inspected, for example. In this case, for example, the defect size is identified as 0.2 μm or less, 0.2 to 0.5 μm, 0.5 to 1 μm, or 1 μm or more. If identified in this way, the grade of the glass substrate 12 can be appropriately classified.

  Next, for example, by using a laser marker of a carbon dioxide laser, a part of the end surface of the glass substrate 12 is melted or sublimated by laser light irradiation, thereby forming each recess 20 of the marker 18 (marking step S110). The marker 18 indicates identification information unique to the glass substrate 12. The identification information is associated with the inspection result of the substrate inspection step S108. As a result, the marker 18 can be used to identify the shape of the glass substrate 12 such as thickness, flatness, and warp shape, and the position, type, and size of the defect. Therefore, according to this example, it is possible to efficiently form the mask pattern thin film 14 and the like. Further, for example, when manufacturing a mask, a mask pattern can be designed while avoiding defects.

  Note that the marking step S110 may irradiate the laser beam a plurality of times for each recess 20 in the marker 18. In this way, variation in the shape of the recess 20 can be reduced, and the reading accuracy of the marker 18 can be improved.

  Next, the marker 18 is read, and the mask pattern thin film 14 to be formed on the glass substrate 12 is determined based on the read marker 18 (thin film determination step S112). In this example, the thin film determination step S112 identifies the surface shape of the glass substrate 12 from the inspection result of the substrate inspection step S108 associated with the marker 18. Then, for example, the type of mask blank suitable for using the glass substrate 12 is selected according to the identified shape such as the warped shape of the main surface. Thereby, the thin film determination step S112 sets the light shielding film necessary for the mask blank, the light shielding film, the phase shift film, and the like as the mask pattern thin film 14 to be formed.

  According to this example, the type of the mask pattern thin film 14 can be determined according to the inspection result of the substrate inspection step S108. Therefore, the glass substrate 12 can be used effectively without waste.

  In this example, in the thin film determination step S112, information indicating the resist film 16 used for the selected mask blank 10 is further associated with identification information of the marker 18. As a result, the marker 18 can be used to further identify the resist film to be applied on the mask pattern thin film 14.

  Following the thin film determination step S112, the determined mask pattern thin film 14 is formed on the main surface of the glass substrate 12 with a film thickness that provides desired optical characteristics (deposition step S114). The mask pattern thin film 14 is inspected (thin film inspection step S116). In this example, the thin film inspection step S116 includes a pass / fail determination step, and determines whether or not the specifications of the mask blanks are met. When the inspection of the thin film inspection step S116 is passed (S116: Pass), a resist film 16 is applied (formed) on the mask pattern thin film 14 (resist film formation step S118), and the applied resist film 16 is inspected ( Resist film inspection step S120). The resist film inspection step S120 includes an acceptance / rejection determination step, and determines whether or not the specifications of the mask blanks are met. If the inspection of the resist film inspection step S120 is passed (S120: Pass), the mask blank 10 is completed.

  In the thin film inspection step S116 and the resist film inspection step S120, for example, a use inspection that affects the pattern transfer is performed such that there are several defects (pinholes, particles) of 0.2 μm or more. In the thin film inspection step S116, for example, a predetermined optical characteristic (such as transmittance) is further inspected.

  Here, in the case of failure in the thin film inspection step S116 (S116: Fail), the mask pattern thin film 14 is peeled from the glass substrate 12 (thin film peeling step S206). Then, the marker 18 of the glass substrate 12 is read, and the thickness of the glass substrate 12 is identified from the inspection result of the substrate inspection step S108 associated with the read marker 18 (thickness identification step S208). Then, when the glass substrate 12 has a thickness that can be regenerated by re-polishing (S210: Yes), the glass substrate 12 is re-polished by the polishing amount corresponding to the thickness identified in the thickness identifying step S208 ( Re-polishing step S212). In the re-polishing step S212, for example, the glass substrate 12 is divided into groups classified by thickness based on the identified thickness, and the glass substrate 12 is polished by a polishing amount set in advance for each group.

  And after re-polishing, it returns to washing | cleaning process S106 and subsequent processes are repeated. In this case, marking process S110 forms the marker 18 for identifying the glass substrate 12 reproduced | regenerated by regrinding. In the film forming step S114, a new mask pattern thin film 14 is formed on the main surface of the glass substrate 12 polished in the repolishing step S212. According to this example, the expensive glass substrate 12 can be used effectively without waste.

  In step S210, whether or not the glass substrate 12 is reproducible is determined by the glass substrate for mask blanks when it is re-polished with the minimum amount necessary to satisfy the quality. Judgment is made based on whether or not the plate thickness remains. When it is determined that regeneration is impossible due to insufficient thickness (S210: No), the glass substrate 12 is discarded.

  If the resist film inspection step S120 fails (S120: Fail), the resist film 16 is peeled from the glass substrate 12 (resist film peeling step S202), and re-polishing is necessary to regenerate the glass substrate 12. It is determined whether or not (S204). In step S204, for example, if the resist film inspection is not passed even if the resist film 16 is reapplied a predetermined number of times, it is determined that repolishing is necessary. In step 204, it may be determined whether re-polishing is necessary based on the inspection result of the substrate inspection step S108.

  When it is determined that re-polishing is unnecessary (S204: No), the marker 18 is read, and the resist film 16 to be applied on the mask pattern thin film 14 is selected based on the read marker 18 (resist selection step S214). ). And the resist film 16 is apply | coated on the thin film 14 for mask patterns (resist re-forming process S216), and it progresses again to resist film test process S120. According to this example, even when the application / formation of the resist film 16 fails, for example, the re-application / reformation can be performed appropriately. In addition, since the resist film 16 to be reapplied / reformed can be selected with certainty, process management can be simplified.

  When it is determined that re-polishing is necessary (S204: Yes), the thin film peeling step S206 and subsequent steps are repeated. In this way, it is possible to regenerate the glass substrate 12 that cannot be regenerated only by recoating / reforming the resist film 16.

  In addition, although description is abbreviate | omitted in the above, it is preferable that the board | substrate test | inspection process S108 further determines whether the glass substrate 12 satisfy | fills required quality, for example. In this case, when it is determined that the necessary quality is not satisfied, for example, after the marker 18 is formed in the marking step S110, the process proceeds to the steps after the thickness identification step S208, and the glass substrate 12 is re-polished. In this way, the glass substrate 12 can be effectively used without further waste. For example, in the case of a glass substrate for mask blanks for ArF excimer laser exposure, the required quality of the glass substrate 12 is, for example, a surface roughness of 0.2 nm or less in RMS, a flatness of 0.5 μm or less, and 0.2 μm or more. This is a specification related to a glass substrate that affects pattern transfer, such as no defect.

  FIG. 4 is a flowchart showing an example of a manufacturing method method for manufacturing a new mask blank 10 using the manufactured mask blank 10. In this example, a chemically amplified resist film is formed on the mask blank 10 as the resist film 16.

  In this example, first, a mask blank 10 that has been manufactured by, for example, collection from a mask manufacturer is prepared (preparation step S302). In the preparation step S302, as the manufactured mask blanks 10, for example, the mask blanks 10 for which a predetermined period (for example, one month or more) has elapsed since the resist film 16 was applied are prepared. In the preparation step S302, a plurality of types of mask blanks 10 on which different resist films 16 are formed may be prepared.

  Next, the resist film 16 of the mask blank 10 is peeled off (resist film peeling step S304). In the resist film peeling step S304, the resist films 16 of the plurality of types of mask blanks 10 may be peeled simultaneously.

  Next, the marker 18 is read, and based on the read marker 18, the resist film 16 formed on the mask blank 10 before the resist peeling is selected (resist selection step S306). Then, the selected resist film 16 is applied (formed) on the mask pattern thin film 14 (resist re-forming step S308).

  In this way, the mask blank 10 can be efficiently regenerated even when the resist film 16 of the manufactured mask blank 10 is deteriorated. Further, the use of the marker 18 can simplify the process management.

Example 1
100 glass substrates for mask blanks for ArF excimer laser exposure according to Example 1 were manufactured. On the end face of the glass substrate, a marker similar to that shown in FIG. 1B was formed by a laser marker using a carbon dioxide (CO ₂ ) gas laser. The output of the laser marker was 20 mW / shot, and each recess was formed by one shot. The size of the entire marker was 3.25 mm × 3.5 mm. In addition, the steps other than the marker formation were the same as in the case of manufacturing a known glass blank for ArF excimer laser exposure mask blanks. When these glass substrates were inspected in the substrate inspection step, all of them satisfied the quality required for the glass substrates for mask blanks for ArF excimer laser exposure.

(Comparative example)
100 glass substrates for mask blanks for ArF excimer laser exposure according to a comparative example were manufactured in the same manner as in the example except that a YAG laser was used instead of the carbon dioxide (CO ₂ ) gas laser. When these glass substrates were inspected in the substrate inspection process, only 27% (27) of the glass substrates for ArF excimer laser exposure mask blanks satisfying the required quality were obtained.

(Example 2)
Under the same conditions as in Example 1 described above, a marker was formed on the side surface which is the end surface of the glass substrate. A glass substrate having a size of 152.4 mm × 152.4 mm × 6.35 mm was used. In addition, as shown in the figure, the marker was formed with a size of 3 mm × 3 mm centering on a position of 7 mm from the corner of the glass substrate on which the glass notch mark is formed and 3.18 mm from the main surface. . Moreover, the opening width L1 of the recessed part which comprises a marker was 170 micrometers, the depth D was 17 micrometers, and the ratio (L1 / D) of the opening width and depth was 10. After forming the concave portion as the marker, the glass substrate end face was cleaned with a cleaning brush, and the glass substrate was inspected for defects. All of them satisfied the quality required for the glass blank for mask blanks for ArF excimer laser exposure. It was. Further, a mask pattern thin film is formed using this glass substrate, and a resist film (average film thickness: 3000 angstroms) is formed on the mask pattern thin film by a spin coating method to form a mask blank for ArF excimer laser exposure. Obtained. The in-plane film thickness uniformity of the resist film formed on the mask blanks was measured. The in-plane film thickness uniformity of the resist film is uniformly arranged (11 × 11 = 121 points) in the entire guarantee area 132 mm × 132 mm (mask pattern formation region) at the center of the substrate, and the spectral reflection type film thickness meter (nano The film thickness is measured by using Metrics Japan Co., Ltd. (AFT6100M), and the in-plane film thickness distribution (film thickness data at each measurement point) is obtained. (Minimum value of film thickness) = (in-plane film thickness uniformity) ”. As a result, the in-plane film thickness uniformity of the resist film was very good at 22 angstroms. Further, a mask was produced using this mask blank, and the CD accuracy of the produced mask satisfied the quality required for the ArF excimer laser exposure mask.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The present invention can be suitably used for, for example, a glass substrate for mask blanks and mask blanks.

It is a figure showing an example of composition of mask blanks 10 concerning one embodiment of the present invention. FIG. 1A is a side view of the mask blank 10. FIG. 1B shows an example of the configuration of the marker 18. It is a figure which shows an example of the detailed shape of the recessed part. 4 is a flowchart showing an example of a method for manufacturing the mask blanks 10. It is a flowchart which shows an example of the manufacturing method method which manufactures the new mask blanks 10 using the manufactured mask blanks 10. FIG.

DESCRIPTION OF SYMBOLS 10 ... Mask blanks, 12 ... Glass substrate, 14 ... Thin film for mask patterns, 16 ... Resist film, 18 ... Marker, 20 ... Recessed part

Claims (14)

A mask blank consisting of a glass substrate and a thin film for a mask pattern formed on the glass substrate,
The glass substrate is formed by irradiating laser light on a mirror-like surface, and includes a recess used as a marker.
The recess is a region excluding 1.2 mm from both sides of the main surface on the end surface orthogonal to the main surface on which a thin film to be a transfer pattern on the glass substrate is formed, and from the corners of the four corners of the glass substrate. It is formed in the area within 10mm,
The mask blank is characterized in that the marker indicates identification information, an identification symbol, or a management symbol unique to the mask blank.   The concave portion is formed in a region outside the optical path of inspection light for inspecting at least a defect existing in a pattern formation region on an end surface orthogonal to the main surface on which the mask pattern thin film is formed on the glass substrate. The mask blank according to claim 1.   3. The mask blank according to claim 1, wherein the surface roughness of the end face is 0.2 nm or less in terms of root mean square roughness Rms.   The mask blank according to any one of claims 1 to 3, wherein the surface roughness of the recess is an arithmetic average surface roughness Ra of 0.1 to 5 nm.   The marker is associated with substrate information related to the glass substrate, and the substrate information includes physical characteristics, optical characteristics, surface morphology of the glass substrate surface, and defects that are unique information of the glass substrate. 5. The mask blank according to claim 1, wherein at least one of them is included. The marker is associated with thin film information about the mask pattern thin film,
6. The mask blank according to claim 1, wherein the thin film information is information including at least one of a surface shape and a defect of a thin film surface of the mask pattern thin film. . A resist film is formed on the mask pattern thin film,
The marker is associated with resist film information relating to the resist film,
The resist film information is information including at least one of physical characteristics, chemical characteristics, surface morphology, material, defects, and formation conditions of the resist film. 6. Mask blanks as described in any one of 6. A mask blank manufacturing method comprising a glass substrate and a mask pattern thin film formed on the glass substrate,
A marking step of irradiating a mirror surface of the glass substrate with a laser beam to form a recess used as a marker,
A film forming step of forming the mask pattern thin film on the main surface of the glass substrate;
A thin film information preparation step for preparing thin film information on the mask pattern thin film after the film formation step;
The marker indicates identification information unique to the mask blank, an identification symbol, or a management symbol,
The recess is a region excluding 1.2 mm from both sides of the main surface on the end surface orthogonal to the main surface on which a thin film to be a transfer pattern on the glass substrate is formed, and from the corners of the four corners of the glass substrate. A mask blank manufacturing method, wherein the mask blank is formed in an area within 10 mm.   The concave portion is formed in a region outside the optical path of inspection light for inspecting at least a defect existing in a pattern formation region on an end surface orthogonal to the main surface on which the mask pattern thin film is formed on the glass substrate. The manufacturing method of the mask blanks of Claim 8.   10. The method of manufacturing a mask blank according to claim 8, wherein the surface roughness of the end face is 0.2 nm or less in terms of root mean square roughness Rms.   The method of manufacturing a mask blank according to any one of claims 8 to 10, wherein the surface roughness of the recess is an arithmetic average surface roughness Ra of 0.1 to 5 nm. After the marking step, further comprising a substrate information preparation step of preparing substrate information on the glass substrate,
The marker is associated with substrate information related to the glass substrate, and the substrate information includes physical characteristics, optical characteristics, surface morphology of the glass substrate surface, and defects that are unique information of the glass substrate. The method for manufacturing a mask blank according to claim 8, wherein at least one of them is included. The marker is associated with thin film information about the mask pattern thin film,
13. The mask blank according to claim 8, wherein the thin film information is information including at least one of a surface shape and a defect of a thin film surface of the mask pattern thin film. Manufacturing method. After the film forming step, further comprising: a resist film forming step for forming a resist film on the mask pattern thin film; and a resist film information preparing step for preparing resist film information relating to the resist film,
The marker is associated with resist film information relating to the resist film,
9. The resist film information is information including at least one of physical characteristics, chemical characteristics, surface morphology, material, defects, and formation conditions of the resist film. The method for producing a mask blank according to any one of 13.

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