JP2017195260A - Method for manufacturing glass-work substrate, glass-work substrate, mask blanks and imprint mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass-work substrate, which is hard to cause an abnormal deformation in an imprint mold during vacuum suction, and which is difficult for cullet to remain.SOLUTION: A method for manufacturing a glass-work substrate for an imprint mold comprises the steps of: (1) preparing a glass plate having first and second main surfaces opposed to each other; (2) forming, in the second main surface of the glass plate, a concave portion having a bottom face and a side wall surrounding the bottom face; (3) providing a first protection layer in a region in the first main surface of the glass plate, where a mesa is to be formed later, which is to be executed before or after the step (2); and (4) immersing the glass plate in an etching liquid with a second protection layer provided on the second main surface of the glass plate to etch the glass plate.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for manufacturing a glass processed substrate, a glass processed substrate, a mask blank, and an imprint mold.

  An imprint method has attracted attention as an alternative technique to the photolithography method. In the imprint method, a transfer material such as a UV curable resin is disposed between a substrate to be transferred and an imprint mold having a predetermined pattern. In this state, the imprint mold pattern is transferred to the transfer material by pressing the imprint mold against the transfer substrate. Furthermore, the transfer material is cured by irradiating the transfer material with light (ultraviolet rays). Thereafter, by removing the imprint mold, a desired transfer material pattern can be formed on the substrate to be processed.

  In the imprint method, the pattern provided in the imprint mold can be transferred as it is to the substrate to be processed. For example, if a fine pattern is formed on the imprint mold, a fine pattern such as a nanoscale can be formed. It can be transferred to a substrate to be processed relatively easily (nanoimprint method).

  Usually, an imprint mold used in the imprint method has a protruding portion called “mesa” at approximately the center of one main surface and a non-through hole called “counterbore” at approximately the center of the opposite main surface. Have.

  A pattern to be transferred to the substrate to be processed is formed at the tip of the mesa. Therefore, the pattern can be transferred to the substrate to be processed by pressing the mesa of the imprint mold against the substrate to be processed through the transfer material.

  The counterbore of the imprint mold is used to suppress entrainment of bubbles when transferring the imprint mold pattern to the substrate to be processed.

Japanese Patent Laying-Open No. 2015-223788

  The imprint mold is usually manufactured from a glass plate.

When forming a mesa on a glass plate, the following steps are performed:
(A) placing a metal layer in a region corresponding to a later mesa on the first major surface of the glass plate;
(B) immersing the glass plate in an etching solution to etch the glass plate;
(C) A glass plate having a mesa on the first main surface is obtained by removing the metal layer.

  On the other hand, when a counterbore is formed on the glass plate, the substantially central portion of the second main surface of the glass plate is ground and polished.

  A glass plate having such a mesa and counterbore is also referred to as a glass processed substrate.

  By the way, when the pattern is actually transferred to the substrate to be processed by the imprint method, first, the imprint mold is attached to the stage with the mesa facing outward. The stage has a through hole in a substantially central portion, and a chuck portion around the opening of the through hole. By sucking the imprint mold using this chuck portion, the imprint mold can be vacuum-adsorbed on the stage.

  Here, in the conventional imprint mold, an irregular deformation may occur in the imprint mold during vacuum suction.

  This is because the etching process as shown in (b) described above is performed when the mesa is formed on the glass plate in the manufacturing process of the glass processed substrate. That is, the second main surface after the etching process (excluding the counterbore portion) tends to have relatively large irregularities and / or steps, and the flatness tends to be large. Therefore, in the imprint mold manufactured through the above-described process, a good contact state cannot be obtained between the second main surface and the stage (more specifically, the chuck portion), and the imprint mold is imprinted during vacuum suction. Irregular deformation (hereinafter also referred to as abnormal deformation) may occur in the print mold.

  Such abnormal deformation of the imprint mold may lead to abnormal deformation of the mesa, in which case it may be difficult to transfer the transfer pattern to the substrate to be processed with high accuracy. In particular, in the nanoimprint method, it is necessary to transfer a very fine pattern of nano order to a substrate to be processed, and even a slight deformation of the mesa greatly reduces the accuracy of the pattern.

  In addition, in the manufacturing method of the glass processing board | substrate of patent document 1, the whole 2nd main surface of a glass plate is coat | covered in the case of the etching process which forms a mesa in the 1st main surface of a glass plate. In this case, the second main surface of the glass plate is not exposed to the etching solution, and the above problem may not occur.

  However, in the manufacturing method of the glass processing board | substrate described in patent document 1, since it does not pass through the etching process of a glass plate, there exists a possibility that the glass waste and polishing slurry which may arise when forming a counterbore remain in a glass processing board | substrate. . Such glass scraps may damage the glass processed substrate and further the imprint mold, or may drop during the imprint process and deteriorate the quality of the processed substrate.

  Therefore, the method of Patent Document 1 is not an effective countermeasure for solving the above-described problem.

  The present invention has been made in view of such a background. In the present invention, during vacuum suction, an imprint mold is unlikely to be abnormally deformed, and a method for producing a glass processed substrate in which glass debris hardly remains. The purpose is to provide. Moreover, it aims at providing the mask blanks and imprint mold which have such a glass processing board | substrate, and also such a glass substrate in this invention.

In the present invention, it is a method for producing a glass processed substrate for imprint mold, having mesa and counterbore,
(1) preparing a glass plate having first and second main surfaces facing each other;
(2) forming a recess having a bottom surface and a side wall surrounding the bottom surface on the second main surface of the glass plate;
(3) The first protection is performed in a region where a mesa is formed later on the first main surface of the glass plate, which is performed before the step (2) or after the step (2). A step of installing a layer;
(4) A step of immersing the glass plate in an etching solution and etching the glass plate in a state where a second protective layer is installed on the second main surface of the glass plate;
A manufacturing method is provided.

Further, in the present invention, the method for producing a glass processed substrate for imprint mold having mesa and counterbore,
(1) preparing a glass plate having first and second main surfaces facing each other;
(2) A first protective layer is installed on a region of the first main surface of the glass plate where a mesa is formed later, and a second protective layer is installed on the second main surface of the glass plate And a process of
(3) immersing the glass plate in a first etching solution and etching the glass plate;
(4) forming a recess having a bottom surface and a side wall surrounding the bottom surface on the second main surface of the glass plate;
(5) immersing the glass plate in a second etching solution and etching the glass plate again;
A manufacturing method is provided.

Moreover, in the present invention, a glass processing substrate for an imprint mold having a glass plate,
The glass plate has first and second main surfaces facing each other,
A mesa is formed on the first main surface, the mesa having a protruding surface and a side surface surrounding the protruding surface,
A counterbore is formed on the second main surface, and the counterbore has a counterbore bottom surface and a counterbore side wall surrounding the counterbore bottom surface,
A glass-worked substrate is provided in which the root mean square roughness Rms of the second main surface excluding the counterbore formed region is smaller than the root mean square roughness Rms of the counterbore bottom surface.

In the present invention,
A glass processing substrate having mesa and counterbore;
A conductive film disposed on at least the protruding surface of the mesa;
Have
Mask blanks, which are glass processed substrates having the characteristics as described above, are provided as the glass processed substrate.

Furthermore, in the present invention,
A glass processing substrate having mesa and counterbore;
A pattern formed on the protruding surface of the mesa;
Have
The glass processing substrate is provided with an imprint mold, which is a glass processing substrate having the characteristics as described above.

  In the present invention, it is possible to provide a method for producing a glass processed substrate in which abnormal deformation does not easily occur in the imprint mold during vacuum suction, and further, glass waste and polishing slurry hardly remain. Moreover, in this invention, the mask blanks and imprint mold which have such a glass processing board | substrate and also such a glass substrate can be provided.

It is a top view of a general imprint mold. It is sectional drawing along the II line of the imprint mold shown in FIG. It is the figure which showed typically one process of the imprint method which transfers a pattern to a to-be-processed substrate using the conventional imprint mold. It is the figure which showed typically one process of the imprint method which transfers a pattern to a to-be-processed substrate using the conventional imprint mold. It is the figure which showed roughly 1 process of the manufacturing method of the conventional imprint mold. It is the figure which showed roughly the flow of the manufacturing method of the glass processing board | substrate by one Embodiment of this invention. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed schematically the flow of the manufacturing method of another glass processing board | substrate by one Embodiment of this invention. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically each process in the manufacturing method shown in FIG. It is the figure which showed typically the cross section of the glass processing board | substrate by one Embodiment of this invention. It is the figure which showed roughly the measurement position of the surface roughness of a sample. It is the figure which showed roughly the measurement position of the surface roughness of a sample. It is the figure which showed roughly the measurement position of the surface roughness of a sample. It is the figure which showed roughly the measurement position of the surface roughness of a sample. It is the figure which showed typically the 1st measuring object field of flatness in the 2nd main surface of a sample. It is the figure which showed typically the 2nd measuring object field of flatness in the 2nd main surface of a sample. It is the figure which showed typically the 3rd measuring object field of flatness in the 2nd main surface of a sample. It is the figure which showed typically the 4th measuring object field of flatness in the 2nd main surface of a sample.

  Hereinafter, an embodiment of the present invention will be described.

  First, terms used in the present application will be described.

  In the present application, a glass plate having “mesa” and “counterbore” is referred to as “glass processing substrate”. “Mesa” and “counterbore” mean a protrusion and a non-through hole formed in a glass plate, respectively. The “glass processed substrate” is manufactured by forming a mesa on a first main surface of a glass plate and forming a counterbore on a second main surface opposite to the first main surface.

  A conductive film may be disposed on the first main surface of the glass processed substrate so as to cover at least the protruding surface of the mesa. A glass processed substrate having such a conductive film is also referred to as “mask blanks”.

  An “imprint mold” can be manufactured by forming a desired pattern on the protruding surface of the mesa in the glass processed substrate. The produced “imprint mold” can be used as a mold in the imprint method as described above.

  FIG. 1 shows a plan view of a conventional general imprint mold. FIG. 2 is a cross-sectional view taken along the line II of the imprint mold shown in FIG.

  As shown in FIGS. 1 and 2, the imprint mold 1 (hereinafter simply referred to as “mold 1”) includes a glass plate 10. Glass plate 10 has a first main surface 12 and a second main surface 14.

  A mesa 20 is formed at a substantially central portion of the first main surface 12 of the glass plate 10, and a counterbore 50 is formed at a substantially central portion of the second main surface 14 of the glass plate 10. Therefore, this glass plate 10 can also be called a “glass processed substrate”. A predetermined pattern 80 is formed on the protruding surface 22 of the mesa 20.

  The mold 1 having such a configuration is used for the imprint method. Hereinafter, a specific use example of the mold 1 will be described with reference to FIGS. 3 and 4.

  3 and 4 schematically show how the pattern is transferred to the substrate to be processed using the mold 1 in the imprint method.

  As shown in FIG. 3, in the imprint method, first, a transfer material 94 is set on the surface 92 of the substrate 90 to be processed. Further, the mold 1 is disposed on the surface 92 side of the substrate 90 to be processed via the transfer material 94. The mold 1 is arranged so that the first main surface 12 faces the surface 92 of the substrate 90 to be processed.

  Next, as shown in FIG. 3, the mold 1 is brought close to the workpiece substrate 90 in a state where the mold 1 is deformed (curved) so that the mesa 20 is convex, and the pattern 80 of the mesa 20 is applied to the transfer material 94. Make contact. Then, the contact area of the mold 1 with the workpiece substrate 90 is gradually expanded from the central portion of the mesa 20 to the periphery.

  This is usually performed by pressing the mold 1 against the substrate 90 so that the deformation of the mold 1 is gradually eased. Thereby, since the bubbles move outward from the contact area, the bubbles easily escape to the outside, and finally, the remaining bubbles contained in the transfer material 94 can be reduced.

  As shown in FIG. 4, finally, the mold 1 is disposed on the workpiece substrate 90 via the transfer material 94 in a completely flat state (a state without deformation).

  Thereafter, the transfer material 94 is cured. Usually, the transfer material 94 is made of a UV curable resin. Therefore, the transfer material 94 can be cured by irradiating the transfer material 94 with ultraviolet rays through the mold 1 in the state shown in FIG. Thereafter, the mold 1 is removed.

  By such an imprinting method, the pattern 80 of the mesa 20 of the mold 1 can be transferred to the surface 92 of the substrate 90 to be processed.

(Conventional method for producing an imprint mold)
Next, a conventional method for manufacturing the mold 1 as shown in FIGS. 1 and 2 will be briefly described.

The conventional mold 1 manufacturing method (hereinafter simply referred to as “conventional manufacturing method”)
(1) forming a mesa on the first main surface of the glass plate;
(2) forming a counterbore on the second main surface of the glass plate;
Is manufactured.

  Among these, the process of (2) is implemented by grinding the substantially center part of the 2nd main surface of a glass plate in a substantially cylindrical shape, and grind | polishing this cylindrical part after that, for example.

On the other hand, the process (1)
Forming a metal layer on a portion of the first main surface of the glass plate where a mesa is formed later;
Immersing the glass plate in an etching solution and etching the glass plate;
Forming a mesa on the first main surface by removing the metal layer;
including.

  Hereinafter, the step of forming the mesa (1) will be described in more detail with reference to FIG.

  In FIG. 5, each process implemented when forming a mesa is shown typically.

  First, a glass plate 10 is prepared as shown in FIG. Glass plate 10 has a first main surface 12 and a second main surface 14. In this example, the counterbore 50 is already formed on the second main surface 14 by the process (2) described above.

  Next, as shown in FIG. 5 (2), the metal layer 30 is placed on the first main surface 12 of the glass plate 10. The metal layer 30 is made of a material such as metal chrome, for example. A resist layer 32 is provided on the metal layer 30.

  Next, a pattern of the resist layer 32 is formed by a general photolithography method. Further, the metal layer 30 is etched through the resist layer.

  As a result, as shown in FIG. 5 (3), the resist layer 32 and the remaining portion 35 of the lower metal layer 30 are formed at the approximate center of the first main surface 12 of the glass plate 10. In other words, portions of the resist layer 32 and the metal layer 30 other than the residual resist layer 32a and the residual metal layer 30a remaining in the substantially central portion of the first main surface 12 of the glass plate 10 are removed. Thereafter, the remaining resist layer 32a of the remaining portion 35 may be removed.

  Next, as shown in FIG. 5 (4), the glass plate 10 having the residual metal layer 30 a is immersed in the etching solution 40. By this etching process, the region of the glass plate 10 that is not covered with the residual metal layer 30a is etched.

  For example, as shown in FIG. 5 (5), the first main surface 12 of the glass plate 10 excluding the lower portion of the residual metal layer 30a becomes the first etching main surface 12a, and the second main surface 12a of the glass plate 10 The main surface 14 becomes the second etching main surface 14a.

  Here, as shown in FIG. 5 (5), the first etching main surface 12a obtained after this etching process is the original first main surface 12 (indicated by a broken line in FIG. 5 (5)). Compared to the height level is reduced. As a result, the mesa 20 covered with the residual metal layer 30a is formed on the first etching main surface 12a of the glass plate 10.

  Next, as shown in FIG. 5 (6), the residual metal layer 30a in the mesa 20 is removed. Thereby, the mesa 20 having the protruding surface 22 and the side surface 24 on the first etching main surface 12a of the glass plate 10 is obtained. That is, the glass processing substrate 60 is manufactured.

  Thereafter, a mold 1 as shown in FIGS. 1 and 2 is formed by forming a desired pattern on the protruding surface 22 of the mesa 20 in the obtained glass processing substrate 60.

  By the way, when a pattern is actually transferred to the workpiece substrate 90 by the imprint method, first, the mold 1 is in a state where the mesa 20 is directed outward (that is, a state where the second etching main surface 14a is inward). Attached to the stage. The stage has a through hole substantially at the center, and has a chuck portion around the through hole. By sucking the mold 1 using this chuck portion, the mold 1 can be vacuum-adsorbed on the stage.

  Here, in the conventional mold 1, abnormal deformation may occur in the mold 1 during vacuum suction.

  This is because, in the conventional manufacturing method, when the mesa 20 is formed on the glass plate 10, the above-described etching process is performed. That is, the second etching main surface 14a obtained after the etching process has relatively large irregularities and / or steps, and thus the flatness TIR (Total Indicated Reading) is deteriorated. Therefore, in the mold 1 manufactured through the process as described above, a good contact state cannot be obtained between the second etching main surface 14a and the stage (more specifically, the chuck portion), and the vacuum adsorption is not performed. At this time, abnormal deformation occurs in the mold 1. Here, the flatness TIR represents the sum of the distances between the highest point and the lowest point when the least square plane is used as a reference.

  Such abnormal deformation of the mold 1 during the stage installation may lead to deformation (for example, twist) of the mesa 20. And when such a deformation | transformation arises in the mesa 20, there exists a possibility that it may become difficult to transfer a transfer pattern to the to-be-processed substrate 90 with high precision. In particular, in the nanoimprint method, it is necessary to transfer a very fine pattern on the order of nanometers to the substrate to be processed, and even a slight deformation of the mesa 20 greatly reduces the pattern accuracy.

  In the mold manufacturing method described in Patent Document 1 described above, the entire second main surface including the counterbore of the glass plate is covered during the etching process for forming the mesa. In this case, the second main surface of the glass plate is not exposed to the etching solution, and thus the above problem may not occur.

  However, in the mold manufacturing method described in Patent Document 1, the counterbore portion of the glass plate is not etched during the formation of the mesa. For this reason, there is a possibility that foreign matters such as glass scraps and polishing slurry generated when the counterbore is formed remain on the glass processed substrate and further on the mold. Such foreign matter may damage the glass processing substrate and the mold in the subsequent process, or may fall off from the mold during the imprint process, and deteriorate the quality of the substrate to be processed.

  Therefore, the method of Patent Document 1 cannot be said to be an effective countermeasure for suppressing abnormal deformation of the mold during vacuum suction.

  On the other hand, in the present invention, as will be described in detail later, it is difficult for foreign matters to remain in the manufacturing process, and abnormal deformation of the mesa hardly occurs during vacuum suction with the stage. It becomes possible to provide the manufacturing method.

(Method of manufacturing a glass processed substrate according to an embodiment of the present invention)
Next, with reference to FIGS. 6-15, an example of the manufacturing method of the glass processing board | substrate by one Embodiment of this invention is demonstrated.

  FIG. 6 schematically shows a flow of a glass processing substrate manufacturing method (hereinafter referred to as “first manufacturing method”) according to an embodiment of the present invention. 7 to 15 schematically show each step in the first manufacturing method.

As shown in FIG. 6, the first manufacturing method is:
(1) preparing a glass plate having first and second main surfaces facing each other (step S110);
(2) a step of forming a recess in the second main surface of the glass plate (step S120);
(3) A step of installing a first protective layer in a region where a mesa is formed later on the first main surface of the glass plate (step S130);
(4) A step (Step S140) of immersing the glass plate in an etching solution and etching the glass plate in a state where the second protective layer is installed on the second main surface of the glass plate;
(5) removing the first protective layer (step S150);
Have

  In addition, process S130 does not necessarily need to be implemented after process S120, for example, process S130 may be implemented before process S120. Further, step S150 may be omitted.

  Hereinafter, each step will be described with reference to FIGS.

(Process S110)
First, a glass plate as a material for a glass processed substrate is prepared.

  FIG. 7 schematically shows an example of a perspective view of a glass plate.

  As shown in FIG. 7, the glass plate 110 has a first main surface 112 and a second main surface 114 that face each other. Moreover, the glass plate 110 has a side end face 116 that connects the first main surface 112 and the second main surface 114.

  The composition of the glass plate 110 is not particularly limited. The glass plate 110 may be made of, for example, quartz glass.

  Moreover, in the example shown in FIG. 7, the glass plate 110 is substantially rectangular shape. However, this is merely an example, and the shape of the glass plate 110 is not particularly limited.

  The glass plate 110 may be provided in a state where the first main surface 112 and the second main surface 114 are polished. For example, the first major surface 112 may have a flatness TIR of 15 nm to 1350 nm and / or a root mean square roughness Rms of 0.001 nm to 0.03 nm. The same applies to the second main surface.

  Here, the flatness TIR of the first main surface 112 is a value when an area of 142 mm × 142 mm at the approximate center of the first main surface 112 is used as a reference of the least square plane.

(Process S120)
Next, as shown in FIG. 8, a recess 145 is formed in the second main surface 114 of the glass plate 110.

  Recess 145 is formed at the approximate center of second main surface 114 of glass plate 110. The recess 145 has a bottom surface 147 and a side wall 149 that surrounds the bottom surface 147. In a normal case, the recess 145 has a substantially cylindrical shape or a substantially quadrangular prism shape.

  The recess 145 is formed by, for example, grinding the second main surface 114 of the glass plate 110 and further polishing.

  The grinding process is performed by grinding the glass plate 110 with a grindstone while supplying a grinding liquid. A plurality of grindstones having different particle sizes may be prepared, and the grindstone may be gradually refined and ground. The polishing process is performed by polishing the glass plate 110 using a polishing pad while supplying the polishing slurry.

  At this stage, bottom surface 147 of recess 145 typically has a root mean square roughness Rms greater than second main surface 114 and a flatness TIR greater than second main surface 114. For example, the bottom surface 147 of the recess 145 may have a root mean square roughness Rms in the range of 0.03 nm to 1 nm. Further, the bottom surface 147 of the recess 145 may have a flatness TIR in the range of 1.5 μm to 20 μm.

  Here, the flatness TIR of the bottom surface 147 of the concave portion 145 is a value when the region of 62 mmφ at the approximate center of the bottom surface 147 is used as a reference of the least square plane.

  Although not shown in FIG. 8, the recess 145 may have a chamfered portion at the opening of the second main surface 114, that is, at the intersection of the second main surface 114 and the side wall 149. . Further, the recess 145 may have an R chamfered portion at the intersection of the bottom surface 147 and the side wall 149.

  In addition, this recessed part 145 becomes counterbore after process S140 mentioned later. In other words, the recess 145 is shaped and dimensioned so that this portion will later form a counterbore.

(Step S130)
Next, a first protective layer is disposed at a substantially central portion of the first main surface 112 of the glass plate 110. Hereinafter, the step S130 will be described in detail with reference to FIGS.

  First, as shown in FIG. 9, the first protective layer 130 is provided so as to cover the entire first main surface 112 of the glass plate 110.

  The material constituting the first protective layer 130 is not particularly limited as long as it is a material that can protect the glass plate 110 in the subsequent etching process (see step S140).

  The first protective layer 130 includes a material containing chromium, for example, at least one of chromium metal, chromium nitride, chromium oxide, chromium carbide, chromium carbonitride, chromium oxynitride, and chromium carbonitride. But it ’s okay.

  The first protective layer 130 is made of a material containing molybdenum, for example, at least one of metal molybdenum, molybdenum nitride, molybdenum oxide, molybdenum carbide, molybdenum carbonitride, molybdenum oxynitride, and molybdenum carbonitride. May be included.

  In addition, the first protective layer 130 may include at least one of a material containing tantalum, for example, a compound such as TaHf, TaZr, and TaHfZr.

  The first protective layer 130 may be made of a material obtained by adding Be, Ge, Nb, Si, C, and / or N to a tantalum compound.

  The first protective layer 130 may include at least one of gold, aluminum, iron, zinc, titanium, and tungsten.

  Note that the first protective layer 130 may be a single layer or a plurality of layers.

  The method for forming the first protective layer 130 is not particularly limited. The first protective layer 130 may be formed by, for example, sputtering, vapor deposition, chemical vapor deposition (CVD), or atomic layer deposition (ALD).

  Although the thickness of the 1st protective layer 130 is not restricted in particular, For example, it is the range of 10 nm-10 micrometers.

  Next, as shown in FIG. 10, a resist layer 132 is provided on the first protective layer 130.

  The resist layer 132 is not particularly limited. As the resist layer 132, those conventionally used can be applied. Further, the method for installing the resist layer 132 is not particularly limited. The resist layer 132 may be disposed on the first protective layer 130 by, for example, a spin coater or a spray coater.

  The thickness of the resist layer 132 is not particularly limited, but is, for example, in the range of 100 nm to 5 μm.

  Next, a pattern of the resist layer 132 is formed by a general photolithography method. In this step, for example, a stepper, an aligner, a laser drawing apparatus, or an electron beam drawing apparatus may be used.

  Next, the first protective layer 130 is etched through the resist layer 132. When the first protective layer 130 contains chromium, a cerium (IV) ammonium nitrate solution known as a chromium etchant, for example, may be used as the etching solution.

  As a result, as shown in FIG. 11, a remaining portion 135 having the resist layer 132 and the lower first protective layer 130 is formed at a substantially central portion of the first main surface 112 of the glass plate 110. In other words, the resist layer 132 and the first protective layer 130 are removed except for the portions of the residual resist layer 132a and the residual protective layer 130a remaining in the substantially central portion of the first main surface 112 of the glass plate 110, respectively. Is done.

  Thereafter, the residual resist layer 132a may be selectively removed.

  In addition, after implementation of this process, the 1st main surface of the glass plate 110 may have changed somewhat from the state before implementation of this process. However, for simplification of description, the first main surface obtained by this process is also represented by the same reference numeral “112” here.

  Through such a process, the first protective layer 130 (residual protective layer 130a) can be disposed at a substantially central portion of the first main surface 112 of the glass plate 110.

  As described above, step S130 is not necessarily performed after step S120. For example, step S130 may be performed before step S120.

(Process S140)
Next, as shown in FIG. 12, the second protective layer 131 is installed on the portion of the second main surface 114 of the glass plate 110 excluding the recess 145.

  The second protective layer 131 may be made of the same material as the first protective layer 130 described above. In addition, the second protective layer 131 may be provided in the same manner as the first protective layer 130 described above.

  The thickness of the second protective layer 131 is not particularly limited, but is, for example, in the range of 100 nm to 10 mm.

  Note that the installation of the second protective layer 131 is not necessarily performed at this stage, and the installation of the second protective layer 131 is performed at any stage before the glass plate 110 is etched in this step S140. May be implemented.

  For example, the installation of the second protective layer 131 may be performed before step S120. In this case, the second protective layer 131 is disposed on the entire second main surface 114 of the glass plate 110, and after the step S120, the second protective layer 131 is formed on the second main surface 114 excluding the recess 145. It may remain.

  Alternatively, the installation of the second protective layer 131 may be performed between step S120 and step S130.

  Next, as shown in FIG. 13, the glass plate 110 having the residual protective layer 130 a and the second protective layer 131 is immersed in the etching solution 140.

  As the etching solution 140, a general solution used for glass etching is used. For example, hydrofluoric acid, mixed solution of hydrofluoric acid and ammonium fluoride, mixed solution of hydrofluoric acid and nitric acid or hydrochloric acid, alkaline detergent, alkali hydroxide containing sodium hydroxide aqueous solution and alkali metal hydroxide A metal aqueous solution, APM (a mixed aqueous solution of ammonium hydroxide, hydrogen peroxide solution, and water) or the like is used. Specific examples of the alkaline detergent include Sun Wash (registered trademark) manufactured by Kao Corporation.

  The etching solution is preferably hydrofluoric acid, a mixed solution of hydrofluoric acid and ammonium fluoride, hydrofluoric acid and nitric acid or hydrochloric acid from the viewpoint of management and control, speed of etching rate, and cost. A mixed solution is preferred. In any case, the concentration of hydrofluoric acid is, for example, 0.01% by mass to 25% by mass.

  The liquid temperature of the etching solution is, for example, 10 ° C. to 70 ° C., preferably 15 ° C. to 25 ° C. If the temperature of the etching solution is too low, the etching rate is slow and productivity is poor. On the other hand, if the temperature of the etching solution is too high, the moisture is volatilized, so that concentration management is difficult.

  By this etching process, the exposed surface of the glass plate 110 that is not covered with the residual protective layer 130a and the second protective layer 131 is etched.

  For example, as shown in FIG. 14, the first main surface 112 excluding the lower portion of the residual protective layer 130a of the glass plate 110 becomes an etching main surface 112a. Further, the bottom surface 147 of the concave portion 145 of the glass plate 110 becomes an etching bottom surface 147a, and the side wall 149 becomes an etching side wall 149a.

  As a result, the recess 145 becomes a counterbore 150. That is, counterbore 150 having etching bottom surface 147a and etching side wall 149a on second main surface 114 of glass plate 110 is obtained.

  The etching amount of the bottom surface 147 of the recess 145 is not particularly limited, but may be in the range of 3 nm to 60 μm, for example. If the etching amount is less than 3 nm, the foreign matter adhering to the glass plate 110 (particularly the recess 145) may not be sufficiently removed. If the etching amount exceeds 60 μm, the roughness of the etching bottom surface 147a of the counterbore 150 may not be ignored.

  Further, as shown in FIG. 14, the etching main surface 112a obtained after this etching process has a height level lower than that of the original first main surface 112 (shown by a broken line in FIG. 14). . As a result, the mesa 120 covered with the residual protective layer 130a is formed on the etching main surface 112a of the glass plate 110.

  Here, since the 2nd main surface 114 of the glass plate 110 is covered with the 2nd protective layer 131, even if this etching process is implemented, the 2nd main surface 114 is not etched. Therefore, in the first manufacturing method, it is possible to maintain the root mean square roughness Rms and flatness TIR of the second main surface 114 of the glass plate 110 within a desired range even after the etching process.

  Moreover, even if foreign matter such as glass scraps and polishing slurry remains on the glass plate 110 when the concave portion 145 is formed in the glass plate 110 in the above-described step S120, such foreign matter is not removed in this etching step. Removed.

  Here, the flatness TIR of the second main surface 114 is determined based on the least-squares plane of a portion obtained by excluding the recess 145 and the surrounding 1 mm region from the 142 mm × 142 mm region at the approximate center of the second main surface 114. This is the value when

(Process S150)
Next, as shown in FIG. 15, the residual protective layer 130a is removed. As a result, the mesa 120 having the protruding surface 122 and the side surface 124 on the etching main surface 112a of the glass plate 110 is obtained. Thereby, the glass processing board | substrate 160 which has the mesa 120 and the counterbore 150 is manufactured.

  At this stage, the second protective layer 131 may or may not be removed from the glass processed substrate 160.

  In particular, when the second protective layer 131 is made of a metal, such a second protective layer 131 is used when holding the glass processing substrate 160 and further mask blanks or imprint molds obtained therefrom on a stage or the like. In addition, it can be used as a film for an electrostatic chuck.

  Further, if necessary, a conductive film may be provided so as to cover at least the protruding surface 122 of the mesa 120 in the obtained glass processed substrate 160. Thereby, mask blanks for imprinting are manufactured.

  Alternatively, a desired pattern may be formed on the protruding surface 122 of the mesa 120. Thereby, an imprint mold is manufactured.

  In such a first manufacturing method, the second main surface 114 is not etched in the etching step of step S140. Therefore, in the first manufacturing method, it is possible to maintain the root mean square roughness Rms and flatness TIR of the second main surface 114 of the glass plate 110 at desired values.

  Therefore, when the glass processing substrate manufactured by the first manufacturing method is applied as an imprint mold, it is possible to significantly suppress the problem that abnormal deformation occurs in the mesa during vacuum suction with the stage.

  In the first manufacturing method, as described above, the foreign matter generated when forming the recess 145 is removed in the etching process of step S140. For this reason, it becomes possible to significantly reduce or avoid the problem that the glass processing substrate to be manufactured, as well as the mask blanks and the imprint mold, are damaged in the subsequent process due to the residual foreign matter. Furthermore, it is possible to significantly reduce or avoid the problem of residual foreign matter falling off from the imprint mold during the imprint process and degrading the quality of the substrate to be processed.

  The first manufacturing method has been described above with reference to FIGS. However, the above description is merely an example, and some or all of the steps may be modified or changed.

  For example, in the above-described step S140, the second protective layer 131 is provided only on the second main surface 114 of the glass plate 110. However, in this step, the second protective layer 131 may be further provided on the side end surface 116 of the glass plate 110.

  Various other changes and modifications are possible.

(Manufacturing method of another glass processing substrate by one embodiment of the present invention)
Next, with reference to FIGS. 16-23, an example of the manufacturing method of another glass processing board | substrate by one Embodiment of this invention is demonstrated.

  FIG. 16 schematically shows a flow of another glass processing substrate manufacturing method (hereinafter referred to as “second manufacturing method”) according to an embodiment of the present invention. Moreover, in FIGS. 17-23, each process in a 2nd manufacturing method is shown typically.

As shown in FIG. 16, the second manufacturing method is:
(1) preparing a glass plate having first and second main surfaces facing each other (step S210);
(2) A first protective layer is installed on a region of the first main surface of the glass plate where a mesa is formed later, and a second protective layer is installed on the second main surface of the glass plate A step of performing (step S220);
(3) a step of immersing the glass plate in a first etching solution and etching the glass plate (step S230);
(4) a step of forming a recess in the second main surface of the glass plate (step S240);
(5) a step of immersing the glass plate in a second etching solution and etching the glass plate again (step S250);
Have

  Hereinafter, each step will be described with reference to FIGS. 17 to 23.

(Step S210)
First, a glass plate as a material for a glass processed substrate is prepared. This step is the same as step S110 in the first manufacturing method described above. Therefore, detailed description is omitted here.

(Step S220)
Next, as shown in FIG. 17, the first protective layer 170 is provided on the first main surface 112 of the glass plate 110. A second protective layer 171 is provided on the second main surface 114 of the glass plate 110.

  The first protective layer 170 is disposed on the first main surface 112 in a region where a mesa is formed later. On the other hand, the second protective layer 171 is provided on the entire surface of the second main surface 114.

  The material constituting the first protective layer 170 is not particularly limited as long as it is a material that can protect the glass plate 110 during the etching process in the subsequent step S230. Moreover, the material which comprises the 2nd protective layer 171 will not be restricted especially if it is a material which can protect the glass plate 110 in the case of the etching process in later process S230 and process S250.

  The first protective layer 170 may be made of the same material as that of the first protective layer 130 in the first manufacturing method described above. Further, the second protective layer 171 may be made of the same material as the second protective layer 131 in the first manufacturing method described above. Note that the first protective layer 170 and the second protective layer 171 may be formed of the same material.

  A method for forming the first protective layer 170 and the second protective layer 171 is not particularly limited. Each of these may be formed by the same method as the first protective layer 130 and the second protective layer 131 in the first manufacturing method described above, for example.

  For example, the first protective layer 170 is formed by depositing a predetermined material layer on the entire first main surface 112 of the glass plate 110 as in step S130 in the first manufacturing method described above. The resist layer may be formed by forming a resist layer patterned by a photolithography method and etching the material layer.

  The first protective layer 170 may have a thickness in the range of 10 nm to 10 μm, for example. The second protective layer 171 may have a thickness in the range of 100 nm to 10 mm, for example.

(Process S230)
Next, the first main surface 112 of the glass plate 110 is etched (first etching process). The first etching process may be performed, for example, by immersing the glass plate 110 in the first etching solution.

  The first etching solution may be a solution containing hydrofluoric acid.

  In FIG. 18, the cross-sectional form of the glass plate 110 after a 1st etching process is shown typically.

  As shown in FIG. 18, a portion of the first main surface 112 of the glass plate 110 that is not covered with the first protective layer 170 is etched by the first etching process. For example, a portion of the first main surface 112 of the glass plate 110 that is not covered with the first protective layer 170 becomes an etching main surface 112a.

  Here, as shown in FIG. 18, the etching main surface 112a obtained after the first etching process has a lower height level (shown by a broken line) than the original first main surface 112. . As a result, the mesa 120 covered with the first protective layer 170 is formed on the etching main surface 112 a of the glass plate 110.

  On the other hand, since the 2nd main surface 114 of the glass plate 110 is previously coat | covered with the 2nd protective layer 171, even if this process S230 is implemented, the 2nd main surface 114 is not etched. Therefore, in the second manufacturing method, it is possible to maintain the root mean square roughness Rms and the flatness TIR of the second main surface 114 of the glass plate 110 within a predetermined range even after the first etching process.

(Step S240)
Next, as shown in FIG. 19, a recess 145 is formed in the approximate center of the second main surface 114 of the glass plate 110. The recess 145 becomes counterbore after step S250 described later. In other words, the recess 145 is shaped and dimensioned so that this portion will later form a counterbore.

  The recess 145 has a bottom surface 147 and a side wall 149 that surrounds the bottom surface 147. In a normal case, the recess 145 has a substantially cylindrical shape or a substantially quadrangular prism shape.

  As described above, the recess 145 is formed by, for example, grinding the second main surface 114 of the glass plate 110 and further polishing.

  Although not shown in FIG. 19, the recess 145 may have a chamfered portion at the opening of the second main surface 114, that is, at the intersection of the second main surface 114 and the side wall 149. . Further, the recess 145 may have an R chamfered portion at the intersection of the bottom surface 147 and the side wall 149.

(Process S250)
Next, the glass plate 110 is immersed in a second etching solution and subjected to an etching process (second etching process).

  Prior to the second etching process, as shown in FIG. 20, a third protective layer 172 is provided on the first main surface 112 (more precisely, the etching main surface 112a) of the glass plate 110. Also good.

  When the first protective layer 170 is not resistant to the second etching solution used in the second etching process, the third protective layer 172 has a first protective layer as shown in FIG. It may be installed so as to cover the layer 170. Alternatively, when the first protective layer 170 is resistant to the second etching solution, the third protective layer 172 does not overlap the first protective layer 170 so that the first main surface 112 is not overlapped. May be installed.

  The material constituting the third protective layer 172 is not particularly limited as long as the material can protect the glass plate 110 during the second etching step.

  For example, the third protective layer 172 may be made of the same material as the first protective layer 170 or the second protective layer 171. The third protective layer 172 may be a single layer or a plurality of layers.

  The third protective layer 172 may be formed by a method similar to that of the first protective layer 170 or the second protective layer 171 described above.

  The thickness of the horizontal portion of the third protective layer 172 is not particularly limited, but is, for example, in the range of 20 nm to 100 μm.

  By providing the third protective layer 172 on the etching main surface 112a of the glass plate 110, it is possible to avoid etching main surface 112a being etched by the second etching solution.

  Next, as shown in FIG. 21, the glass plate 110 is immersed in the second etching solution 141, and the exposed portion is etched. For example, the recess 145 formed in the second main surface 114 is etched.

  With the second etching process, as shown in FIG. 22, the bottom surface 147 of the recess 145 becomes the etching bottom surface 147a, and the side wall 149 becomes the etching side wall 149a.

  As a result, the recess 145 becomes a counterbore 150. That is, counterbore 150 having etching bottom surface 147a and etching side wall 149a on second main surface 114 of glass plate 110 is obtained.

  The etching amount of the bottom surface 147 of the recess 145 in the second etching process is not particularly limited, but may be in the range of 3 nm to 60 μm, for example. If the etching amount is less than 3 nm, the foreign matter attached to the glass plate 110 in step S240 may not be sufficiently removed. If the etching amount exceeds 60 μm, the roughness of the etching bottom surface 147a of the counterbore 150 may not be ignored.

  Next, as shown in FIG. 23, the first protective layer 170 and the third protective layer 172 are removed. Note that at this stage, the second protective layer 171 may or may not be removed from the glass processed substrate 160.

  In particular, when the second protective layer 171 is made of a metal, such a second protective layer 171 is used when holding the glass processed substrate 160 and further mask blanks or imprint molds obtained therefrom on a stage or the like. In addition, it can be used as a film for an electrostatic chuck.

  Through the above steps, the mesa 120 having the protruding surface 122 and the side surface 124 is obtained on the etching main surface 112 a of the glass plate 110, and the counterbore 150 is obtained on the second main surface 114 of the glass plate 110.

  As a result, the glass processing substrate 160 having the mesa 120 and the counterbore 150 is manufactured.

  Thereafter, if necessary, a conductive film may be provided so as to cover at least the protruding surface 122 of the mesa 120 in the obtained glass processed substrate 160. Thereby, mask blanks for imprinting are manufactured.

  Alternatively, a desired pattern may be formed on the protruding surface 122 of the mesa 120. Thereby, an imprint mold is manufactured.

  In such a second manufacturing method, the second main surface 114 excluding the recess 145 is not etched in any of the first etching process in step S230 and the second etching process in step S260. Therefore, in the second manufacturing method, it is possible to maintain the root mean square roughness Rms and flatness TIR of the second main surface 114 of the glass plate 110 at desired values.

  Therefore, when the glass processing substrate manufactured by the second manufacturing method is applied as an imprint mold, it is possible to significantly suppress the problem that abnormal deformation occurs in the mesa during vacuum suction with the stage.

  Further, in the second manufacturing method, as described above, the foreign matter generated when forming the recess 145 is removed by the second etching process in step S260. For this reason, it becomes possible to significantly reduce or avoid the problem that the glass processing substrate to be manufactured, as well as the mask blanks and the imprint mold, are damaged in the subsequent process due to the residual foreign matter. Furthermore, it is possible to significantly reduce or avoid the problem of residual foreign matter falling off from the imprint mold during the imprint process and degrading the quality of the substrate to be processed.

  Heretofore, the second manufacturing method has been described with reference to FIGS. However, the above description is merely an example, and some or all of the steps may be modified or changed.

  For example, in the above-described step S220, the second protective layer 171 is installed so as to cover the entire second main surface 114 of the glass plate 110. However, in this step, the second protective layer 171 may be disposed on the second main surface 114 so as not to cover a portion where the concave portion 145 (that is, the counterbore 150) will be formed later.

  In this case, a marking pattern (recess) can be formed on the second main surface 114 of the glass plate 110 after step S230. Thereafter, in step S240, the recess 145 is formed in the second main surface 114 with this depression as a guideline, so that the center line of the mesa 120 and the counterbore 150 obtained later can be easily matched.

  In step S220, the second protective layer 171 may be further disposed on the side end surface 116 of the glass plate 110. Similarly, in step S250, the third protective layer 172 may be provided also on the side end face 116 of the glass plate 110.

  Furthermore, in the second manufacturing method, the etching main surface 112a of the glass plate 110 is protected by the third protective layer 172 before the second etching process in step S250. However, the installation of the third protective layer 172 is not always necessary.

  That is, the etching main surface 112a of the glass plate 110 may be further etched by the second etching process in step S250. In this case, for example, if the etching amount of the first main surface 112 of the glass plate 110 in the first etching process in step S230 and the second etching process in step S250 is known in advance, both etching processes are performed. Later, a mesa 120 having a predetermined height can be obtained.

  Various other changes and modifications are possible.

(Glass processing board by one embodiment of the present invention)
Next, with reference to FIG. 24, one structural example of the glass processing board | substrate by one Embodiment of this invention is demonstrated.

  FIG. 24 schematically shows a cross section of a glass processed substrate (hereinafter referred to as “first glass processed substrate”) according to an embodiment of the present invention. As shown in FIG. 24, the first glass processing substrate 200 is composed of a glass plate 210.

  The glass plate 210 has a first main surface 212 and a second main surface 214 that face each other, and a side end surface 216 that connects both the main surfaces 212 and 214. A mesa 220 is formed at a substantially central portion of the first main surface 212 of the glass plate 210, and a counterbore 250 is formed at a substantially central portion of the second main surface 214 of the glass plate 210.

  The mesa 220 includes a protruding surface 222 and a side surface 224 that surrounds the protruding surface 222. Meanwhile, the counterbore 250 includes a counterbore bottom surface 247 and a counterbore side wall 249 surrounding the counterbore bottom surface 247.

  The central axes of the counterbore 250 and the mesa 220 substantially coincide.

  Although not shown in FIG. 24, the first glass processing substrate 200 may further include a conductive film on the first main surface 212 side.

  Hereinafter, each part of the 1st glass processing board | substrate 200 is demonstrated in detail.

(Glass plate 210)
The composition of the glass plate 210 is not particularly limited. For example, the glass plate 210 may be quartz glass containing 90 mass% or more of SiO ₂ . Quartz glass has a feature that it has a higher transmittance of ultraviolet rays than general soda-lime glass. In addition, quartz glass has the characteristics that the coefficient of thermal expansion is small and the dimensional change of the concavo-convex pattern due to temperature change is small as compared with general soda lime glass.

When the glass plate 210 is made of quartz glass, the quartz glass may contain TiO ₂ in addition to SiO ₂ . As the TiO ₂ content increases, the density of OH groups on the surface of the glass plate 210 increases, and the affinity for the transfer material increases.

For example, quartz glass may contain 90 to 98% by mass of SiO ₂ and ₂ to 10% by mass of TiO ₂ . When the TiO ₂ content is 2 to 10% by mass, the coefficient of thermal expansion near room temperature is substantially zero, and the dimensional change near room temperature hardly occurs.

Quartz glass may contain trace components other than SiO ₂ and TiO ₂ , but preferably does not contain trace components.

  The shape and dimensions of the glass plate 210 are not particularly limited. The glass plate 210 may be rectangular, for example. For example, the glass plate 210 may have a square shape of 152 mm × 152 mm. Moreover, the glass plate 210 may have a thickness in the range of 2.2 mm to 12.7 mm, for example.

  First main surface 212 of glass plate 210 (excluding mesa 220; the same applies hereinafter) may have a root mean square roughness Rms in the range of 0.01 nm to 1 nm. Further, the first main surface 212 of the glass plate 210 may have a flatness TIR in the range of 0.03 μm to 1500 μm.

  On the other hand, second main surface 214 (excluding counterbore 250. The same applies hereinafter) of glass plate 210 may have a root mean square roughness Rms of 0.03 nm or less. Further, the second main surface 214 of the glass plate 210 may have a flatness TIR of less than 1.5 μm, for example, a flatness TIR of 1.0 μm or less.

  The flatness TIR of the second main surface 214 of the glass plate 210 defined here is from the peripheral region of 5 mm width and the center of the second main surface 214 of the glass plate having a size of 152 mm × 152 mm. It means the flatness TIR measured in the part excluding the region with a diameter of 66 mmφ.

(Mesa 220)
The mesa 220 is configured to have a protruding surface 222 and a side surface 224. The shape of the mesa 220 is not particularly limited. The mesa 220 may have a shape such as a substantially cylindrical shape or a substantially quadrangular prism shape, for example.

  The dimension of the protruding surface 222 of the mesa 220 is not particularly limited. For example, when the protruding surface 222 of the mesa 220 is formed in a rectangular shape, the protruding surface 222 may have a size of 10 mm to 55 mm in length × 10 mm to 105 mm in width.

  The height of the mesa 220, that is, the height of the side surface 224 is, for example, in the range of 10 nm to 50 μm.

  The protruding surface 222 of the mesa 220 may have a root mean square roughness Rms of 0.001 nm to 0.03 nm and a flatness TIR of 0.01 μm to 0.1 μm.

  Here, the flatness TIR of the protruding surface 222 of the mesa 220 is based on the area of 24 mm × 31 mm in the portion excluding the area having a width of 1 mm among the protruding surface having a size of 26 mm × 33 mm, as a reference of the least square plane. Is the time value.

(Counterbore 250)
Counterbore 250 is configured to have a counterbore bottom surface 247 and a counterbore side wall 249. The shape of the counterbore 250 is not particularly limited. The counterbore 250 may have a shape such as a substantially cylindrical shape or a substantially quadrangular prism shape, for example.

  When the counterbore 250 has a substantially cylindrical shape, the diameter of the counterbore bottom surface 247 may be in a range of 60 mm to 116 mm. On the other hand, the depth of the counterbore 250, that is, the height of the counterbore side wall 249 is, for example, in the range of 3 mm to 6 mm.

  The counterbore bottom surface 247 of the counterbore 250 has a root mean square roughness Rms larger than that of the second main surface 214 of the glass plate 210. For example, the counterbore bottom surface 247 of the counterbore 250 may have a root mean square roughness Rms in the range of 0.03 nm to 1 nm.

  Similarly, the counterbore side wall 249 of the counterbore 250 may have a root mean square roughness Rms in the range of 0.001 nm to 1 nm.

  Counterbore 250 may have a chamfered portion at the opening of second main surface 214. In this case, the root mean square roughness Rms of the C chamfered portion may be in the range of 0.001 nm to 1 nm.

  Further, the counterbore 250 may have an R chamfered portion at the intersection of the counterbore bottom surface 247 and the counterbore side wall 249.

(Conductive film)
Although not shown in FIG. 24, the first glass processing substrate 200 may further include a conductive film on the first main surface 212 side of the glass plate 210.

  Such a conductive film may be installed, for example, so as to cover only the mesa 220 (the projecting surface 222), or so as to cover the mesa 220 (the projecting surface 222) and the entire first main surface 212. It may be arranged.

  As the conductive film, for example, a material used for the first protective layer described above may be used. For example, the conductive film may include a material containing chromium, a material containing molybdenum, and / or a material containing tantalum.

  The conductive film may be formed by a film formation method such as sputtering, vapor deposition, chemical vapor deposition (CVD), or atomic layer deposition (ALD).

(Feature)
The first glass processing substrate 100 has a feature that the root mean square roughness Rms of the second main surface 214 excluding the area where the counterbore 250 is formed is smaller than the root mean square roughness Rms of the bottom face 247 of the counterbore.

  When the first glass processing substrate 100 having such a feature is applied to an imprint mold, the problem that abnormal deformation occurs in the mesa during vacuum suction with the stage as described above is significantly suppressed. Can do.

  Next, examples of the present invention will be described.

Example 1
A glass processed substrate was manufactured by the first manufacturing method described above. Specifically, the following steps were performed.

(Formation of recesses)
First, a glass plate was prepared. As the glass plate, quartz glass of 152 mm length × 152 mm width was used. The root mean square roughness Rms on the two main surfaces of the glass plate was 0.03 nm. Further, the flatness TIR on each main surface was 1.0 μm.

  Next, a substantially central portion of the second main surface of the glass plate was ground and polished to form a substantially circular counterbore having a diameter of 64 mmφ at the central portion of the second main surface. The depth of the counterbore is about 5.25 mm. Thereafter, a portion between the counterbore side wall and the second main surface was chamfered (C = 0.4 mm). Further, the portion between the side wall and the bottom surface of the counterbore was chamfered (R = 1.0 mm).

  The glass plate obtained by the above steps is particularly referred to as “Sample 1-1”.

(Mesa formation)
Next, the 1st protective layer was installed in the approximate center part (region of length 26mm x width 33mm) of the 1st main surface of sample 1-1.

  The first protective layer was formed by a method combining the pattern processing of the resist layer and the etching processing as shown in FIGS.

  The first protective layer had a three-layer structure of a chromium oxide layer (30 nm), a metal chromium layer (100 nm), and a chromium oxide layer (50 nm) from the side close to the glass plate. Each layer was formed by sputtering.

  Next, the 2nd protective layer was installed in the area | region except the recessed part of the 2nd main surface of a glass plate by the sputtering method. The second protective layer was a chromium nitride layer, and the thickness was 250 nm.

  Next, the glass plate was immersed in an etching solution at room temperature for 500 minutes. The etching solution was a 20 mass% hydrofluoric acid solution.

  After the etching treatment, the glass plate was taken out from the etching solution. Thereafter, the first and second protective layers were removed.

  Thereby, a glass processed substrate (hereinafter referred to as “sample 1-2”) having a mesa on the first main surface and a counterbore on the second main surface was obtained. In Sample 1-2, the mesa size was 26 mm long × 33 mm wide × 30 μm high. The size of the counterbore was diameter 64 mmφ × depth 5.25 mm.

(Evaluation)
The following evaluation was performed using Sample 1-1 and Sample 1-2 obtained as described above.

(Surface roughness measurement)
In each sample, the surface roughness at each position of the second main surface and the counterbore was measured. A scanning white interferometer (manufactured by Zygo) was used for the measurement.

  25 to 28 schematically show the measurement positions of the surface roughness in Sample 1-1 and Sample 1-2. In these drawings, a plan view of the second main surface side of each sample is shown.

  In FIG. 25, the measurement position of the surface roughness in the 2nd main surface of a sample is shown. Moreover, in FIG. 26, the measurement position of the surface roughness in the bottom face of the counterbore of a sample is shown. FIG. 27 shows the measurement position of the surface roughness on the side wall of the counterbore of the sample. Furthermore, in FIG. 28, the measurement position of the surface roughness in the chamfered portion of the counterbore of the sample is shown.

As shown in FIG. 25, the surface roughness of the second main surface of the sample is P ₁ (0,55 mm), P ₂ (55 mm) when the center coordinate of the second main surface is (0,0). , 0), P ₃ (0, −55 mm) and P ₄ (−55 mm, 0).

  At these four locations, the root mean square roughness Rms in a region of 0.14 mm × 0.11 mm was measured. A value obtained by averaging the four values was defined as “first surface roughness Rms (1)”.

As shown in FIG. 26, the measurement of the surface roughness of the bottom face of the counterbore of the sample is performed by assuming that the center coordinates of the second main surface are (0, 0), Q ₁ (0, 20 mm), Q ₂ (20 mm , 0), Q ₃ (0, −20 mm) and Q ₄ (−20 mm, 0).

  At these four locations, the root mean square roughness Rms in a region of 0.14 mm × 0.11 mm was measured. A value obtained by averaging the four values was defined as “second surface roughness Rms (2)”.

As shown in FIG. 27, the measurement of the surface roughness on the side wall of the counterbore of the sample is carried out by viewing the second main surface from the top, R ₁ (0 o'clock), R ₂ (3 o'clock), R ₃ (6 o'clock) and Measurements were made at four locations of R ₄ (9 o'clock). The height position of the measurement point on the side wall is a position approximately half the depth of the counterbore.

  At these four locations, the root mean square roughness Rms in a region of 0.14 mm × 0.11 mm was measured. A value obtained by averaging the four values was defined as “third surface roughness Rms (3)”.

As shown in FIG. 28, the measurement of the surface roughness at the C-chamfered portion of the counterbore of the sample is S ₁ (0, 32 mm), S ₂ when the center coordinate of the second main surface is (0, 0). Measurements were made at four locations (32 mm, 0), S ₃ (0, −32 mm), and S ₄ (−32 mm, 0).

  At these four locations, the root mean square roughness Rms in a region of 0.14 mm × 0.11 mm was measured. A value obtained by averaging the four values was defined as “fourth surface roughness Rms (4)”.

  Table 1 below collectively shows the measurement results obtained in Sample 1-1 and Sample 1-2.

この結果から、サンプル１−１とサンプル１−２の間で、ザグリの底面の第２の表面粗さＲｍｓ（２）、ザグリの側壁の第３の表面粗さＲｍｓ（３）、およびザグリのＣ面取り部の第４の表面粗さＲｍｓ（４）に、差が生じていることがわかる。一方、サンプル１−１とサンプル１−２の間で、第２の主表面の第１の表面粗さＲｍｓ（１）には、差が生じていないことがわかる。

From this result, between sample 1-1 and sample 1-2, the second surface roughness Rms (2) of the bottom face of the counterbore, the third surface roughness Rms (3) of the counterbore side wall, and the counterbore of the counterbore It can be seen that there is a difference in the fourth surface roughness Rms (4) of the C chamfered portion. On the other hand, it can be seen that there is no difference between the sample 1-1 and the sample 1-2 in the first surface roughness Rms (1) of the second main surface.

  Further, from the comparison of the first surface roughness Rms (1) and the second surface roughness Rms (2) in the sample 1-2, the root mean square roughness of the second main surface (excluding the counterbore) is It was confirmed that it was significantly smaller than the root mean square roughness.

(Flatness TIR measurement)
In each sample, the flatness TIR of the second main surface was measured. For measuring the flatness TIR, an oblique incidence flatness measuring device (manufactured by Corning Tropel) was used. Further, the flatness TIR was evaluated in four measurement target regions.

  29 to 32 schematically show measurement target regions of the flatness TIR on the second main surface. In these drawings, a plan view of the second main surface side of each sample is shown.

  FIG. 29 shows a first measurement target region 381 on the second main surface 314 of the sample. The first measurement target region 381 is a portion of the second main surface 314 of the sample having a length of 152 mm × width of 152 mm, excluding the surrounding region having a width of 5 mm and the region having a diameter of 66 mmφ from the center, that is, FIG. In FIG. 4, the region is indicated by hatching.

  The flatness TIR obtained in the first measurement target region 381 is referred to as “first flatness”.

  FIG. 30 shows a second measurement target region on the second main surface of the sample. The second measurement target region 382 is a region between a circle having a diameter of 116 mmφ from the center and a circle having a diameter of 66 mmφ from the center of the second main surface 314 of the sample having a length of 152 mm × width of 152 mm, that is, FIG. In FIG. 4, the region is indicated by hatching.

  The flatness TIR obtained in the second measurement target region 382 is referred to as “second flatness”.

  FIG. 31 shows a third measurement target region on the third main surface of the sample. The third measurement target region 383 is a region between a circle having a diameter of 86 mmφ from the center and a circle having a diameter of 66 mmφ from the center in the second main surface 314 of the sample having a length of 152 mm × width of 152 mm, that is, FIG. In FIG. 4, the region is indicated by hatching.

  The flatness TIR obtained in the third measurement target region 383 is referred to as “third flatness”.

  FIG. 32 shows a fourth measurement target region on the fourth main surface of the sample. The fourth measurement target region 384 is a region between a circle having a diameter of 142 mmφ from the center and a circle having a diameter of 116 mmφ from the center in the second main surface 314 of the sample having a length of 152 mm × width of 152 mm, that is, FIG. In FIG. 4, the region is indicated by hatching.

  The flatness TIR obtained in the fourth measurement target region 384 is referred to as “fourth flatness”.

  Table 2 below collectively shows the flatness TIR measurement results obtained in Sample 1-1 and Sample 1-2.

この結果から、サンプル１−１とサンプル１−２の間で、第１〜第４の平坦度のいずれにおいても、有意な差異が生じていないことがわかる。このように、第２の主表面（ザグリを除く）の平坦度ＴＩＲは、エッチング前後で変化しておらず、有意に小さな平坦度ＴＩＲが維持されていることが確認された。

From this result, it can be seen that there is no significant difference between the sample 1-1 and the sample 1-2 in any of the first to fourth flatnesses. Thus, the flatness TIR of the second main surface (excluding the counterbore) did not change before and after etching, and it was confirmed that a significantly small flatness TIR was maintained.

(Evaluation of optical properties)
In Sample 1-2, the glossiness, haze, image clarity, and peak reflectance of the second main surface and the bottom surface of the counterbore were measured.

  Of these, the glossiness was evaluated based on the amount of reflected light incident at an incident angle of 20 ° based on ISO2813. The haze was measured based on ISO 13803. The image clarity was measured based on ASTM D5767. Further, the peak reflectivity was evaluated from the amount of reflected light incident at an incident angle of 20 ° ± 0.009905 °.

  All of these indices were measured using an all-in-one gloss meter (manufactured by Rhopoint).

  Table 3 below summarizes the measurement results obtained for Sample 1-2.

（残留異物の評価）
サンプル１−２において、ザグリの各部分をＳＥＭで観察し、ザグリにおける残留異物の有無について評価を行った。

(Evaluation of residual foreign matter)
In Sample 1-2, each part of the counterbore was observed with an SEM, and the presence or absence of residual foreign matter in the counterbore was evaluated.

  First, from Sample 1-2, each part of the bottom face, side face, C chamfered part, and R chamfered part of the counterbore was cut and collected. In order to prevent foreign matter from adhering to the sample during the cutting process, cutting is performed while blowing air at a wind speed of 1.5 m / sec or more through the HEPA filter to the sample in a clean environment of class 100. Carried out.

  Observation was carried out at 10 points in each collected part.

  As a result, no foreign matter was observed in any part. (That is, the total number of foreign objects = 0).

  From the above evaluation results, the second main surface (excluding the counterbore) of sample 1-2 has a small mean square roughness Rms, and no glass dust remains in the counterbore of sample 1-2. Was confirmed. Therefore, when such a sample 1-2 is used for an imprint mold, it is expected that the problem of abnormal deformation of the mesa and the problem of quality degradation as in the conventional case are significantly improved.

(Comparative Example 1)
A glass processed substrate was produced by the same method as in Example 1 described above.

  However, in the comparative example 1, the second protective layer was not provided on the second main surface of the glass plate before the etching process in the above-described (formation of mesa). That is, the etching process was performed with the second main surface exposed.

  The glass plate obtained after the above-described (depression formation) stage is particularly referred to as “Sample 2-1”. Further, the glass processed substrate obtained after the above-described (mesa formation) stage is particularly referred to as “sample 2-2”.

  Using the obtained Sample 2-1 and Sample 2-2, the evaluation as described above was performed.

  Table 4 below collectively shows the results of the surface roughness measurement obtained in Sample 2-1 and Sample 2-2.

この結果から、第１の表面粗さＲｍｓ（１）〜第４の表面粗さＲｍｓ（４）のいずれにおいても、サンプル２−２における値は、サンプル２−１における値よりも上昇していることがわかる。特に、エッチング処理によって、第２の主表面の表面粗さＲｍｓ（１）が大きくなっていることがわかる。

From this result, in any of the first surface roughness Rms (1) to the fourth surface roughness Rms (4), the value in the sample 2-2 is higher than the value in the sample 2-1. I understand that. In particular, it can be seen that the surface roughness Rms (1) of the second main surface is increased by the etching process.

  Next, Table 5 below collectively shows the flatness TIR measurement results obtained in Sample 2-1 and Sample 2-2.

この結果から、サンプル２−２では、第１〜第４の平坦度のいずれにおいても、サンプル２−１における第１〜第４の平坦度よりも大きくなっていることがわかる。

From this result, it can be seen that in Sample 2-2, any of the first to fourth flatnesses is larger than the first to fourth flatnesses in Sample 2-1.

  Next, Table 6 below collectively shows measurement results of various optical characteristics obtained in Sample 2-2.

このように、サンプル２−１のエッチング処理により、第２の主表面（ザグリを除く）の二乗平均粗さおよび平坦度ＴＩＲが上昇することが確認された。

Thus, it was confirmed that the root mean square roughness and the flatness TIR of the second main surface (excluding the counterbore) were increased by the etching process of Sample 2-1.

(Comparative Example 2)
A glass plate having counterbore was produced by the following method.

  As the glass plate, the one shown in Example 1 was used.

  The substantially central portion of the second main surface of the glass plate was ground and polished by the same method as in Example 1 described above. As a result, a glass plate having a substantially circular counterbore having a diameter of 64 mmφ and a depth of 5.25 mm was obtained at the center of the second main surface.

  Thereafter, a portion between the counterbore side wall and the second main surface was chamfered (C = 0.4 mm). Further, the portion between the side wall and the bottom surface of the counterbore was chamfered (R = 1.0 mm).

  The glass plate obtained by the above steps is particularly referred to as “Sample 3-1”.

(Evaluation of residual foreign matter)
In Sample 3-1, each part of the counterbore was observed with an SEM by the method shown in Example 1 above, and the presence or absence of residual foreign matter in the counterbore was evaluated.

  As a result, a total of 11 foreign objects were observed from each part.

  Thus, in the glass plate which has the counterbore which did not pass through an etching process, it was confirmed that foreign materials, such as glass waste, exist in the counterbore.

  DESCRIPTION OF SYMBOLS 1 Imprint mold, 10 Glass plate, 12 1st main surface, 12a 1st etching main surface, 14 2nd main surface, 14a 2nd etching main surface, 20 mesa, 22 Projection surface, 24 Side surface, 30 Metal layer, 30a Residual metal layer, 32 Resist layer, 32a Residual resist layer, 35 Residual portion, 40 Etching solution, 50 Counterbore, 60 Glass processed substrate, 80 pattern, 90 Substrate, 92 Surface, 94 Transfer material, 110 Glass Plate, 112 first main surface, 112a etching main surface, 114 second main surface, 116 side end surface, 120 mesa, 122 protruding surface, 124 side surface, 130 first protective layer, 130a residual protective layer, 131 second Protective layer, 132 resist layer, 132a residual resist layer, 135 remaining portion, 140 etching solution 141 second etching solution, 145 recess, 147 bottom surface, 147a etching bottom surface, 149 side wall, 149a etching side wall, 150 counterbore, 160 glass processing substrate, 170 first protective layer, 171 second protective layer, 172 third Protective layer, 200 first glass processed substrate, 210 glass plate, 212 first main surface, 214 second main surface, 216 side end surface, 220 mesa, 222 protruding surface, 224 side surface, 247 counterbore bottom surface, 249 counterbore Side wall, 250 counterbore, 314 sample second main surface, 381 first measurement target region, 382 second measurement target region, 383 third measurement target region, 384 fourth measurement target region.

Claims (19)

A method for producing a glass processing substrate for an imprint mold having a mesa and counterbore,
(1) preparing a glass plate having first and second main surfaces facing each other;
(2) forming a recess having a bottom surface and a side wall surrounding the bottom surface on the second main surface of the glass plate;
(3) The first protection is performed in a region where a mesa is formed later on the first main surface of the glass plate, which is performed before the step (2) or after the step (2). A step of installing a layer;
(4) A step of immersing the glass plate in an etching solution and etching the glass plate in a state where a second protective layer is installed on the second main surface of the glass plate;
A manufacturing method comprising:   2. The manufacturing method according to claim 1, wherein in the step (4), the bottom surface of the recess is etched by a thickness of 3 nm to 60 μm. The step (3)
Installing a first protective layer on the entire first main surface;
Placing a resist layer pattern on the first protective layer;
Etching the first protective layer through the pattern of the resist layer to leave the first protective layer in a region of the first main surface where a mesa is formed later;
The manufacturing method of Claim 1 or 2 which has these. Further, after the step (4),
(5) The manufacturing method according to any one of claims 1 to 3, further comprising a step of removing the first protective layer.   The said 2nd protective layer is a manufacturing as described in any one of Claims 1 thru | or 4 installed in the said 2nd main surface except the said recessed part of the said glass plate after the process of said (2). Method.   The manufacturing method according to any one of claims 1 to 4, wherein the second protective layer is disposed on the entire second main surface of the glass plate before the step (2). A method for producing a glass processing substrate for an imprint mold having a mesa and counterbore,
(1) preparing a glass plate having first and second main surfaces facing each other;
(2) A first protective layer is installed on a region of the first main surface of the glass plate where a mesa is formed later, and a second protective layer is installed on the second main surface of the glass plate And a process of
(3) immersing the glass plate in a first etching solution and etching the glass plate;
(4) forming a recess having a bottom surface and a side wall surrounding the bottom surface on the second main surface of the glass plate;
(5) immersing the glass plate in a second etching solution and etching the glass plate again;
A manufacturing method comprising:   The method according to claim 7, wherein, in the step (2), the second protective layer is disposed on a portion of the second main surface excluding a region where a recess is formed later. The step (2)
Installing a first protective layer on the entire first main surface;
Placing a resist layer pattern on the first protective layer;
Etching the first protective layer through the pattern of the resist layer to leave the first protective layer in a region of the first main surface where a mesa is formed later;
The manufacturing method of Claim 7 or 8 which has these.   The manufacturing method according to claim 7, wherein in the step (5), the bottom surface of the recess is etched by 3 nm to 60 μm. Further, between the steps (3) and (4) or between the steps (4) and (5),
(6) A step of covering the first main surface of the glass plate with a third protective layer,
The manufacturing method according to claim 7, comprising: Furthermore, after the step (5),
(7) The manufacturing method according to any one of claims 7 to 11, further comprising: removing the first protective layer and, if present, the third protective layer. A glass processing substrate for an imprint mold having a glass plate,
The glass plate has first and second main surfaces facing each other,
A mesa is formed on the first main surface, the mesa having a protruding surface and a side surface surrounding the protruding surface,
A counterbore is formed on the second main surface, and the counterbore has a counterbore bottom surface and a counterbore side wall surrounding the counterbore bottom surface,
A glass-worked substrate in which a root mean square roughness Rms of the second main surface excluding a region where the spot facing is formed is smaller than a root mean square roughness Rms of the spot facing bottom.   The said counterbore is a glass processing board | substrate of Claim 13 which has C chamfering part in the cross | intersection part of the said 2nd main surface and the said counterbore side wall.   The said counterbore is a glass processing board | substrate of Claim 13 or 14 which has a R chamfering part in the cross | intersection part of the said counterbore side wall and the said counterbore bottom face.   The glass processed substrate according to any one of claims 13 to 15, wherein the root mean square roughness Rms on the second main surface is 0.03 nm or less. The glass plate has a dimension in which the second main surface has a length of 152 mm × width of 152 mm,
In the second main surface, a flatness TIR measured in a portion excluding a region having a width of 5 mm and a region having a diameter of 66 mmφ from the center in a region having a length of 152 mm × width of 152 mm is less than 1.5 μm. The glass processing board | substrate as described in any one of Claims 13 thru | or 16 which is. A glass processing substrate having mesa and counterbore;
A conductive film disposed on at least the protruding surface of the mesa;
Have
The said glass processing board | substrate is a mask blank which is a glass processing board | substrate as described in any one of Claims 13 thru | or 17. A glass processing substrate having mesa and counterbore;
A pattern formed on the protruding surface of the mesa;
Have
The said glass processing board | substrate is an imprint mold which is a glass processing board | substrate as described in any one of Claims 13 thru | or 17.

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