JP2013071884A - Glass substrate, and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glass substrate which is suitable for suppressing film exfoliation at a boundary portion between a chamfering portion and a main surface portion by improving fracture resistance at the chamfering portion.SOLUTION: This glass substrate, which is a glass substrate having a chamfering portion between a main surface portion and an end surface portion, includes a plurality of recessed parts formed at least on the end surface portion and the chamfering portion, wherein each of the plurality of recessed parts has a width in the plane direction of 10 to 200 nm.

Description

  The present invention relates to a glass substrate and a method for producing the glass substrate.

  Since a thin film silicon solar cell (thin film photoelectric conversion device) can use a glass substrate, compared to a crystalline silicon solar cell, the amount of silicon used as a material is small, and production at low cost is possible. Research and development are active.

  As a manufacturing method thereof, a method of forming a photoelectric conversion cell using a plasma CVD method is used, and a form in which amorphous silicon or a microcrystalline silicon film is used for a photoelectric conversion layer is generally studied. The photoelectric conversion cell is composed of a photoelectric conversion layer and various electrodes.

  A specific manufacturing method generally used will be described. Means for sequentially forming a transparent electrode film, a photoelectric conversion layer, and a reflective electrode layer on a transparent insulating glass substrate is used. A technique for absorbing a large amount of light with a thinner photoelectric conversion layer is necessary, and the formation of a texture structure is used as the method. The texture structure is a structure in which irregularities are formed on the surface of the film. The purpose is to reduce reflection at the interface and lengthen the path length of incident light by changing the incident angle of light. It is said. Therefore, the wavelength of light that is efficiently scattered differs depending on the height difference and the period in the plane direction in the texture structure. The ratio of the scattered transmittance to the total transmittance is called a haze ratio, and it is desirable that the haze ratio with respect to the wavelength of light absorbed in the photoelectric conversion layer is high.

  As the glass substrate used for the thin film silicon solar cell, a glass substrate having a metric size and a film thickness of about 1 to 5 mm is used from the viewpoint of productivity and strength. Further, since the size of the glass substrate required from the user side is not uniform, the glass substrate is cut to be produced from a large glass substrate to a desired size. Although the cut surface (expressed as an end surface) of the cut glass substrate looks smooth visually, there are many fine scratches and many structures that are easy to peel off on the flakes. Therefore, a chamfering process called C chamfering or A chamfering is often performed on the end surface of the peripheral portion of the substrate. The purpose of this treatment is to remove the corners in the vicinity of the cut surface of the sharp glass substrate, thereby suppressing cracks caused by scratches on the glass substrate and preventing injury during handling.

  Patent Document 1 describes that the polishing wheel is moved along the edge of the protruding portion of the glass plate in a state where the glass plate is fixed by the supporting jig so that a part of the glass plate protrudes from the supporting jig. ing. Thus, according to Patent Document 1, even if there is a slight positional variation of the polishing wheel that contacts the glass plate, it is possible to prevent a large increase in the material removed compared to polishing a rigid glass plate. Therefore, it is said that the edge shape of the glass plate can be made consistent.

  In Patent Document 2, the end surface portion of the plate glass is polished to be flat and the maximum surface unevenness thereof is 0.04 mm or less, and the boundary between the end surface portion and the flat surface portion of the plate glass has a surface maximum unevenness of 0. 0. It is described that the finishing process is performed to be 007 mm or less. Thereby, according to patent document 2, since internal stress can be made hard to concentrate on the edge part of plate glass, even if it heat-treats plate glass by the simpler method conventionally, the performance as fireproof glass is maintained. It is supposed to be possible.

  In Patent Document 3, after the rough polishing process is performed with the first polishing tool on the end surface portion of the glass substrate, and the final polishing process is sequentially performed with the second polishing tool that is finer than the first polishing tool, When the edge part of the glass substrate and the boundary between the front surface and the back surface are finer than the second polishing tool, a specific polishing process is performed with a third polishing tool having a grain, and the root mean square slope of the roughness curve is 0.01. It is described that a chamfered surface is formed as follows. As a result, according to Patent Document 3, even if tensile stress due to the deflection of the glass substrate or an inappropriate temperature distribution acts on the chamfered surface, stress concentration does not occur on the chamfered surface, and the end surface and the chamfered surface of the glass substrate. It is said that the breaking strength of will increase.

JP 2011-26195 A Japanese Patent No. 3308447 JP 2011-84453 A

  In the chamfering process of the peripheral edge portion of the glass substrate used in the thin film silicon solar cell, a mechanical polishing process using a polishing tool such as a grindstone or a polishing cloth is generally used. In that case, when the chamfered portion is enlarged and observed, the unevenness in the chamfered portion has a height of at least about several μm (the height between the peak portion and the valley portion), and the formed valley portion has an acute shape. And the depth is not uniform. Since these irregularities have a shape with a sharp angle, the substrate is likely to bend or break during heat treatment, and cracks are easily generated during contact. Thereby, it is difficult to obtain high fracture resistance and it is difficult to remove foreign matters.

  Since all the glass substrates described in Patent Documents 1 to 3 are in a state in which the chamfered portion is processed by mechanical polishing, there is a high possibility that the same problem will occur.

  Further, in the technique described in Patent Document 1, since the end face of the glass plate is not polished, a large number of fine scratches left at the time of cutting remain, and the fine scratches also induce substrate deflection and breakage during heat treatment. It becomes easy and it is easy to produce the crack at the time of contact.

  In the techniques described in Patent Documents 2 and 3, since the polishing is performed in many stages while gradually reducing the grains, the time required for polishing increases and the number of work steps increases, resulting in a decrease in productivity. there is a possibility.

  Further, in the techniques described in Patent Documents 1 and 2, a thin film formed on a glass substrate due to the presence of discontinuity regarding the flatness of the surface at the boundary between the chamfered portion and the surface forming the mirror surface. Is easy to peel.

  In this regard, in the technology of Patent Document 3, it is described that the chamfered surface is formed so that the angle formed between the tangent line of the chamfered surface and the front surface / back surface is 10 ° or more and 30 ° or less. If it is less than 10 °, the polishing area on the end face side when chamfering the face is narrowed, and glass chipping remaining at the boundary between the end face and the front surface / back surface becomes insufficient, which is not preferable. Is described. That is, in the technique of Patent Document 3, ensuring continuity regarding the flatness of the surface at the boundary between the chamfered portion and the surface is positively excluded.

  The present invention has been made in view of the above, and is a glass substrate suitable for improving fracture resistance in a chamfered portion and suppressing film peeling at a boundary portion between the chamfered portion and the main surface portion, and a method for manufacturing the glass substrate The purpose is to obtain.

  In order to solve the above-described problems and achieve the object, a glass substrate according to one aspect of the present invention is a glass substrate having a chamfered portion between a main surface portion and an end surface portion, and at least the end surface portion and A plurality of recesses formed in the chamfered portion are provided, and each of the plurality of recesses has a planar arrangement pitch of 10 nm or more and 200 nm or less.

  According to the present invention, the sharp shape of the chamfered portion and the valley portion existing in the end surface portion can be made smooth, and a smooth and continuous surface is formed even at the boundary between the chamfered portion and the mirror surface portion. The glass substrate suitable for the manufacturing method which can be provided can be provided. That is, it is possible to provide a glass substrate suitable for improving the fracture resistance in the chamfered portion and suppressing the film peeling at the boundary portion between the chamfered portion and the main surface portion.

Drawing 1 is a mimetic diagram of a glass substrate before processing in an embodiment. FIG. 2 is an enlarged schematic view of a chamfered portion before processing in the embodiment. Drawing 3 is a process sectional view showing a manufacturing method to a glass substrate concerning an embodiment. FIG. 4 is a process cross-sectional view illustrating a manufacturing method for the glass substrate according to the embodiment. FIG. 5 is an SEM photograph in which the chamfered portion before and after processing in the embodiment is enlarged and observed. FIG. 6 is a schematic diagram showing a change in the machining shape of the chamfered portion in the embodiment. FIG. 7 is a cross-sectional view illustrating a photoelectric conversion module to which the glass substrate according to the embodiment is applied. FIG. 8 is a cross-sectional view of a thin film solar cell module to which the glass substrate according to the embodiment is applied.

  Embodiments of a glass substrate and a glass substrate manufacturing method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In the figure used, the scale used for easy understanding may be different from the actual one.

Embodiment.
First, the glass substrate before processing in the embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a glass substrate before processing. FIG. 2 is an enlarged cross-sectional view showing the configuration of part A in FIG.

  The glass substrate 100 before processing which will be described later is a transparent insulating substrate, and includes, for example, a main surface portion 100a, a main surface portion 100b (not shown), an end surface portion 100c, and a chamfered portion 100d.

  The main surface portion 100a is, for example, a surface that should become the main surface portion 101a (see FIGS. 7 and 8). The main surface portion 101a is, for example, a surface opposite to the light receiving surface, and is a surface on which a thin film photoelectric conversion layer is deposited. The main surface portion 100a is a flat surface subjected to a mirror surface treatment, as shown in FIG. 2 in which the portion A of FIG. 1 is enlarged.

  The main surface portion 100b is, for example, a surface that should become the main surface portion 101b (see FIGS. 7 and 8). The main surface portion 101b is, for example, a light receiving surface, and is a surface opposite to the main surface portion 101a. Although not shown, the main surface portion 100b is a flat surface that has been subjected to a mirror surface treatment, like the main surface portion 100a.

  The end surface part 100c is a cut surface when it is cut and produced so as to become a glass substrate of a desired size from a large glass substrate, for example.

  The chamfered portion 100d is a portion disposed between the main surface portion 100a and the end surface portion 100c in the glass substrate 100, and a chamfering process is performed on the corner portion in the vicinity of the end surface portion 100c in the glass substrate 100 by a polishing process. Part. The chamfering process is, for example, a process represented by C chamfering or A chamfering.

  The chamfered portion 100d is a surface having irregularities as shown in FIG. In FIG. 2, the unevenness is extremely expressed. In the chamfered portion 100d, as shown by B in FIG. 2, a valley-like portion generated by polishing is generated. In addition, a discontinuous portion 100ad1 whose surface shape changes suddenly exists as shown by C in FIG. 2 at the boundary portion 100ad between the mirror-finished main surface portion 100a and the chamfered portion 100d having irregularities. The discontinuous portion 100ad1 is a portion having discontinuity regarding the flatness of the surface.

  Next, a manufacturing method for the glass substrate according to the embodiment will be described with reference to FIGS. 3 and 4 are process cross-sectional views illustrating a manufacturing method for a glass substrate.

  In the process shown in FIG. 3, the glass substrate 100 as described with reference to FIGS. 1 and 2 is prepared. It is preferable that the thickness of the glass substrate 100 is 0.8 mm or more and 5 mm or less. If the thickness of the glass substrate 100 is thinner than 0.8 mm, the glass substrate 100 may be damaged when a film is formed in a later process or when it is transported between apparatuses. Moreover, when the thickness of the glass substrate 100 is thicker than 5 mm, it becomes difficult to guide light having the required intensity to the photoelectric conversion unit 103 (see FIGS. 7 and 8).

In the process shown in FIG. 4, the main surface portion 100a and the chamfered portion of the glass substrate 100 are sprayed on the glass substrate 100 under a reduced pressure environment (gas phase hydrofluoric acid treatment is performed), for example. Etching is simultaneously performed on 100d and the end face portion 100c. Thereby, the surface texture structure is formed on the main surface portion 101a of the glass substrate 101, and the chamfered portion 100d and the end surface portion 100c are surface-treated. That is, a plurality of fine concave portions are simultaneously formed in the main surface portion 101a, the chamfered portion 100d, and the end surface portion 100c of the glass substrate 101. This method utilizes the fact that the etching rate of impurities (for example, alkaline impurities) contained in a trace amount in the glass substrate 100 is extremely low as compared with SiO ₂ which is the main component of glass.

Specifically, the glass substrate 100 is placed in a container that can be evacuated and highly resistant to corrosive HF gas, and the flow-controlled HF gas or HF / H ₂ O is used under reduced pressure. Exposure to etching gas (process gas) containing it. When the glass substrate 100 is etched in the thickness direction by 500 nm to 2000 nm, the main surface portion 101a of the glass substrate 101 is uneven and a surface texture structure is formed. In this case, the pressure is preferably about 100 to 10 kPa, and the haze ratio indicating the degree of light scattering can be improved.

  In this step, since impurities (for example, alkaline impurities) in the glass substrate 100 are isotropically etched using the mask material, the chamfered portion 100d and the end surface are added to the mirror-finished main surface portion 101a. Also in the portion 100c, a texture structure having a mortar-shaped valley (a plurality of concave portions) having a width of 10 nm to 200 nm begins to be formed. Further, since a mask material (for example, alkaline impurities) further appears during the etching of a large valley that progresses from the beginning of etching, a large valley (second recess) is formed in each of the chamfered portion 100d and the end surface portion 100c. A feature is that a shape in which small mortar-shaped valleys (a plurality of recesses) are added along the slope (inner surface) is obtained. At this time, the width of the large valley is, for example, 3 μm or more.

  FIG. 5 is an SEM image obtained by observing the surfaces of the chamfered portions 100d and 101d.

  FIG. 5A is a view of the surface of the chamfered portion 100d before the processing shown in FIG. 4 is performed. As shown in FIG. 5 (a), in the chamfered portion 100d before processing, there are many steep valleys, irregularities having a size of several μm are formed, and minute linear cracks (microscopic) are formed on the surface. It can be seen that there are cracks). In other words, in the chamfered portion 100d before processing, the trough portion to be formed has an acute angle shape with the mechanical polishing process, and the depth is not uniform. Since these irregularities have a shape with a sharp angle, the substrate is likely to bend or break during heat treatment, and cracks are easily generated during contact. Thereby, it is difficult to obtain high fracture resistance and it is difficult to remove foreign matters.

  On the other hand, in the chamfered portion 101d after processing by the gas phase HF treatment, as shown in FIG. 5B, it was confirmed that the surface had a smooth shape and there was no steep valley.

  It can be seen that it is covered with fine concave portions having a small period (width in the plane direction) of 10 nm or more and 200 nm or less. From this result, it can be confirmed that minute cracks observed on the original surface (see FIG. 5A) are removed.

  If the period of the minute recesses is smaller than 10 nm, the crystallinity of the transparent electrode film 102 is obtained when the transparent electrode film 102 (see FIGS. 7 and 8) is grown on the main surface portion 101a in a later step. May be reduced. Further, if the period of the fine recesses is larger than 200 nm, the transparent electrode film 102 is formed at the uneven portions when the transparent electrode film 102 (see FIGS. 7 and 8) is grown on the main surface portion 101a in a later step. As a result, a large grain boundary that divides the film is formed in the transparent electrode film 102, which may reduce the conductivity of the transparent electrode film 102.

Further, from the SEM image shown in FIG. 5B, it can be seen that there are 100 or more fine recesses in a 10 μm square, and that it is 1 or more in 1 μm ² in terms of density. Thus, the higher the density of the concave portions having a minute period, the more difficult the thin film deposited in the manufacturing process is to peel off, and it is possible to suppress dust generation during the manufacturing process.

  Further, for example, it is also characteristic that concave portions having a large cycle of 3 μm or more (a plurality of second concave portions) and concave portions having a small cycle of 10 nm to 200 nm (a plurality of concave portions) are mixed. In addition, the period of the recessed part used here refers to the planar direction distance between the convex parts in an unevenness | corrugation, ie, the width | variety of the planar direction of a recessed part.

  In addition, since the uneven shape before the processing has a size of several μm (see FIG. 5A), in order to relax the sharp shape of the unevenness, in the vapor phase HF treatment, 500 nm or more Etching in the thickness direction is necessary.

  FIG. 6A shows the progress of etching using a schematic view near the boundary between the main surface portion 100a and the chamfered portion 100d. The chamfered portion 100d has steep irregularities generated by the polishing as described above before the vapor-phase hydrofluoric acid treatment. However, as shown in FIG. In the valley portion, the etching proceeds so that the width of the valley is widened (with side etching). As a result, the steep valley present in the chamfered portion 101d is widened at the acute angle portion of the valley bottom, and the shape of the valley portion (second concave portion) becomes gentle. As a result, it is easy to remove foreign matter that has entered the valley (second recess).

  Further, by performing the gas phase hydrofluoric acid treatment also on the main surface portion 100a, a continuous texture shape, that is, a continuous portion 101ad1 is formed at the boundary portion 101ad between the main surface portion 101a and the chamfered portion 101d. Delamination of the film due to a change in stress due to an abrupt change in temperature is suppressed. The continuous portion 101ad1 is a portion having continuity regarding the flatness of the surface.

  As the fracture resistance evaluation of the glass substrate, when the fracture start pressure by three-point bending was confirmed, in the original glass substrate (see FIG. 3 and FIG. 5 (a)), the fracture occurred at an average of about 90 MPa, In the processed glass substrate (see FIG. 4 and FIG. 5B), it was found that the fracture resistance was improved to an average of about 220 Mpa by performing the processing by the vapor-phase hydrofluoric acid treatment. It was possible to reduce the micro cracks that were the starting point of the fracture that existed in the early stage by making the surface with a microscopic recess having a mortar shape formed by vapor-phase hydrofluoric acid treatment. I think it depends.

  After preparing a glass substrate 101 having irregularities on the main surface part 100a subjected to the mirror finish on one side while smoothing the sharp irregularities of the chamfered part 100d by the method as described above, for example, as shown in FIG. A thin-film Si solar cell is formed through the steps.

A transparent electrode film 102 is formed on a transparent glass substrate 101. A transparent conductive oxide layer such as ITO or SnO ₂ is often used for the transparent electrode film 102. Further, a texture structure having fine unevenness corresponding to the fine unevenness formed on the glass substrate 101 is continuously formed on the surface of the transparent electrode film 102.

  A photoelectric conversion unit 103 is formed on the transparent electrode film 102. The photoelectric conversion unit 103 has a structure in which a p-type silicon semiconductor layer 103a, an i-type amorphous silicon photoelectric conversion layer 103b, and an n-type silicon semiconductor layer 103c are stacked from the transparent electrode film 102 side. It can be formed using a CVD method.

  The i-type amorphous silicon photoelectric conversion layer 103b is used as the i-type photoelectric conversion layer in the photoelectric conversion unit 103. The i-type amorphous silicon photoelectric conversion layer 103b is formed of an i-type amorphous silicon-based semiconductor material. An alloy such as (SiGe) or silicon carbide (SiC) is also used. The p-type silicon semiconductor layer 103a is required to have high conductivity and high light transmittance, and silicon carbide (SiC) to which boron (B) or the like is added is used.

  A back electrode film 104 is formed on the photoelectric conversion unit 103. The back electrode film 104 is required to have good conductivity and light reflectivity, and Ag or Al is often used. Further, in order to suppress reaction / diffusion with the photoelectric conversion unit 103, a stacked structure of a plurality of electrode layers can be provided.

  A photoelectric conversion cell 201 as shown in FIG. 7 is configured by the laminated structure from the transparent electrode film 102 to the back electrode film 104 as described above. Needless to say, the glass substrate according to this embodiment can also be applied to a structure called a tandem type in which a plurality of photoelectric conversion units are stacked.

  Further, when actually manufacturing a thin film silicon solar cell module, a plurality of thin film photoelectric conversion cells are electrically connected in series, so that photoelectric conversion layers and electrodes between adjacent thin film photoelectric conversion cells are electrically connected. A groove for separation is formed by a method such as laser scribing, and has a structure as shown in FIG. A groove 11 in FIG. 8 is a groove obtained by scribing the transparent electrode film 102 in order to separate the transparent electrode film 102. The groove 12 is a groove formed after the photoelectric conversion unit 103 is formed in order to electrically connect the back electrode film 104 and the transparent electrode film 102. Each of the groove 11 and the groove 12 is filled with a film formed after the groove is formed. The groove 13 is a groove formed after the back electrode film 104 is formed in order to electrically isolate the back electrode film 104.

  In the photoelectric conversion cell 201 obtained by such means, in addition to being able to utilize light scattering by the formed texture structure and obtaining high power generation efficiency, sharp irregularities in the chamfered portion of the glass substrate Therefore, the effect of suppressing peeling of the formed photovoltaic layer and breakage of the substrate due to thermal stress can be obtained.

  As described above, in the manufacturing method according to the embodiment, by exposing a glass substrate chamfered by polishing to a process gas containing HF gas, a plurality of fine patterns having a width in a planar direction of 10 nm or more and 200 nm or less are obtained. Concave portions are simultaneously formed in the main surface portion, the chamfered portion, and the end surface portion. As a result, the sharp shape of the chamfered portion and the valley portion that existed in the end surface portion can be made into a smooth shape, so that resistance to chipping due to impact on the end surface portion is increased and chipping of the glass substrate is less likely to occur. Become. In addition, even when warping due to heat or the like occurs, there is an effect of improving fracture resistance, and it is easy to remove foreign substances attached to the valleys. In addition, since a smooth and continuous surface can be formed at the boundary between the chamfered portion and the mirror surface portion, it is possible to suppress peeling of the formed film during the manufacturing process. That is, the fracture resistance in the chamfered portion can be improved, and film peeling at the boundary between the chamfered portion and the main surface portion can be suppressed.

  Moreover, the glass substrate concerning embodiment is suitable for such a manufacturing method. That is, according to the embodiment, it is possible to provide a glass substrate suitable for improving the fracture resistance in the chamfered portion and suppressing the film peeling at the boundary portion between the chamfered portion and the main surface portion.

  In addition, in the manufacturing method according to the embodiment, in addition to the necessity of performing polishing over several stages while gradually reducing the grains, a step of forming a texture structure on the main surface portion and a chamfered portion, and Since the process for surface treatment of the end face part is shared, the increase in the number of processes is suppressed, so that the chamfered part and the minute unevenness of the end face part have a smooth shape without reducing productivity. Can do.

Further, in the glass substrate according to the embodiment, a plurality of fine concave portions are arranged at an arrangement density of 1 / μm ² or more in the end face portion 101c and the chamfered portion 101d. As a result, the surface area of the chamfered portion 101d can be increased, so that the adhesion of the film covering the chamfered portion 101d (for example, the transparent electrode film 102 shown in FIGS. Generation can be suppressed.

  In the glass substrate according to the embodiment, a plurality of fine recesses are formed on the inner surface of the recess having a width in the plane direction of 3 μm or more. Thereby, even when a foreign substance adheres to the recess having a width in the plane direction of 3 μm or more, the foreign substance can be easily removed.

  In the glass substrate according to the embodiment, a plurality of fine recesses are also formed in the main surface portion. Thereby, the continuity regarding the flatness of the surface in the boundary part of a main surface part and a chamfering part can be increased, and peeling of a film | membrane can be suppressed.

  Further, in the glass substrate according to the embodiment, a plurality of fine concave portions are continuously formed so as to straddle the boundary portion between the main surface portion and the chamfered portion. Thereby, the continuity regarding the flatness of the surface in the boundary part between the main surface part and the chamfered part can be further increased, and peeling of the film can be further suppressed.

  In the glass substrate according to the embodiment, the glass substrate contains at least one of alkali metal (for example, sodium or potassium) or alkaline earth metal (for example, calcium), magnesium, and aluminum. Thereby, the etching selectivity with glass can be ensured during the etching process, and a plurality of fine recesses can be easily formed in the main surface portion, the chamfered portion, and the end surface portion.

  Moreover, in the glass substrate concerning embodiment, the thickness of a glass substrate is 0.8 mm or more and 5 mm or less. Thereby, the intensity | strength light requested | required can be guide | induced to the photoelectric conversion unit 103 (refer FIG. 7, FIG. 8), suppressing the damage of the glass substrate 100. FIG.

  In the above embodiment, the vapor phase HF treatment is used as a method for forming a plurality of fine recesses in the main surface portion, the chamfered portion, and the end face portion. However, instead of the vapor phase HF treatment, HF is used as an etchant. The wet etching process described above may be performed.

  As described above, the glass substrate and the glass substrate manufacturing method according to the present invention are useful for manufacturing a thin-film silicon solar cell.

DESCRIPTION OF SYMBOLS 11 Groove part 12 Groove part 13 Groove part 100, 101 Glass substrate 100a, 101a Main surface part (surface which carried out the mirror surface process)
100b, 101b Main surface portion (light receiving surface)
100c, 101c End face portion 100d, 101d Chamfered portion 102 Transparent electrode film 103 Photoelectric conversion unit 103a p-type silicon semiconductor layer 103b i-type amorphous silicon photoelectric conversion layer 103c n-type silicon semiconductor layer 104 Back electrode film 201 Photoelectric conversion cell

Claims (10)

A glass substrate having a chamfered portion between a main surface portion and an end surface portion,
A plurality of recesses formed in at least the end face part and the chamfer part;
Each of the plurality of recesses has a planar width of 10 nm or more and 200 nm or less. ^2. The glass substrate according to claim 1, wherein the plurality of concave portions are arranged at an arrangement density of 1 piece / 1 μm ² or more in the end face portion and the chamfered portion. A plurality of second recesses formed in the end face part and the chamfer part;
The glass substrate according to claim 1, wherein each of the plurality of second recesses has a width in the plane direction of 3 μm or more. The glass substrate according to claim 3, wherein a plurality of the recesses are formed on the inner surface of the second recess. The glass substrate according to any one of claims 1 to 4, wherein the plurality of recesses are further formed on at least one surface of the two main surface portions. The glass substrate according to claim 5, wherein the plurality of concave portions are continuously formed so as to straddle a boundary portion between the main surface portion and the chamfered portion. The glass substrate according to any one of claims 1 to 6, wherein the glass substrate includes at least one of an alkali metal or an alkaline earth metal, magnesium, and aluminum. The glass substrate according to any one of claims 1 to 7, wherein a thickness of the glass substrate is 0.8 mm or more and 5 mm or less. A processing step of forming a texture structure on the main surface portion of the glass substrate having a chamfered portion between the main surface portion and the end surface portion;
In the processing step, a plurality of concave portions are simultaneously formed in the main surface portion and the chamfered portion,
Each of the plurality of recesses has a planar width of 10 nm or more and 200 nm or less. The method for manufacturing a glass substrate according to claim 9, wherein in the processing step, the plurality of recesses are formed using a process gas containing HF gas.