TW201922661A - glass substrate - Google Patents

Abstract

A glass substrate 1 has a first major surface 2 and a second major surface 3. The first major surface 2 has a surface roughness Ra of 0.2 nm or less and the second major surface 3 has a surface roughness Ra in a center region 4 thereof of 0.3 to 1.0 nm. The second major surface 3 has, in an outer peripheral region 5, a roughened region A that has a surface roughness Ra that is greater than the surface roughness Ra of the center region 4 by 0.2 nm or more.

Description

Glass base board

The present invention relates to a glass substrate.

As is well known, liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), and organic electroluminescence are used for image display devices in recent years. Flat panel displays (hereinafter simply referred to as FPDs) such as displays (Organic Electroluminescence Display, OELD) have become mainstream. With regard to these FPDs, weight reduction is being promoted. Therefore, the glass substrates used in FPDs have also been required to be thinner.

The glass substrate is obtained by cutting a sheet-shaped glass (ribbon-shaped glass) formed into a strip shape by, for example, a sheet glass forming method typified by various down-draw methods, in the longitudinal direction. The width direction of the cut sheet glass (a direction parallel to the main surface of the strip sheet glass and a direction orthogonal to the long side direction, hereinafter the same) is further cut to a predetermined size. Each cut surface needs to be polished or the like.

However, when an FPD is manufactured using such a glass substrate, electrostatic charging during the manufacturing process may become a problem. That is, glass as an insulator is easily charged. For example, when a glass substrate is placed on a mounting table and a predetermined process is performed, the glass substrate may be charged due to contact and separation of the glass substrate and the mounting table (sometimes referred to as For peeling). When a conductive object approaches a charged glass substrate, a discharge occurs, and various elements formed on the main surface of the glass substrate or electrode wires constituting an electronic circuit are damaged due to the discharge, or the glass substrate itself is damaged. Yu (sometimes referred to as insulation damage or electrostatic damage). In addition, the charged glass substrate is liable to adhere to the mounting table, and there is a possibility that the glass substrate may be damaged by forcibly peeling it off. These are, of course, causes of poor display, and are therefore phenomena that should be avoided as much as possible.

As a method for avoiding such a phenomenon, for example, it is conceivable to apply a predetermined gas to the back surface of the glass substrate (the main surface on the side in contact with the mounting surface of the mounting table) and subject the back surface to surface treatment. A roughening method (for example, refer to Patent Document 1). The larger the contact area between the glass substrate and the mounting surface, the larger the charge amount at the time of peeling. Therefore, by roughening the back surface of the glass substrate in contact with the mounting surface, the glass substrate and the mounting surface are reduced. The contact area of the surface is required to suppress the charging during peeling. In addition, in view of the smoother back surface of the glass substrate, it is easier to adhere to a smooth surface such as a mounting surface, and the contact area between the glass substrate and the mounting surface is reduced, thereby making it difficult for the glass substrate to adhere to the mounting surface. In order to prevent breakage of the glass substrate during peeling.
[Prior Art Literature]
[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2014-80331

[Problems to be Solved by the Invention]
The roughening is generally performed uniformly over the entire area of the main surface of one side in the glass substrate. However, it is known that in a state where the degree of roughening is uniform over the entire area of the main surface, when the handleability of an actual glass substrate is considered, it may not necessarily be appropriate. In other words, in the actual peeling step, the pins provided on a plurality of locations on the mounting table are raised to thereby peel the glass substrate from the mounting table. At this time, the glass substrate was peeled from the end. When such a peeling operation is considered, if the surface roughness distribution is in a uniform state, there is a possibility that the effect of roughening may not be sufficiently obtained. In other words, there may be a surface roughness distribution suitable for an actual peeling operation. In addition, if only the ease of peeling is taken into consideration, it is only necessary to increase the degree of roughening (surface roughness) of the back surface as a whole. However, if this is done, the roughening process takes more time than necessary. Not so good in terms of cost.

In view of the above, in this specification, a glass substrate having a surface roughness distribution of a main surface suitable for an actual peeling operation at a low cost is a technical problem to be solved.
[Means for solving problems]

The above-mentioned problem is solved by the glass substrate of this invention. That is, this glass substrate is a glass substrate having a first main surface and a second main surface, and is characterized in that the surface roughness Ra of the first main surface is 0.2 nm or less, and the surface roughness Ra of the central region of the second main surface It is 0.3 nm or more and 1.0 nm or less. In the outer peripheral region of the second main surface, a surface roughened region showing a surface roughness Ra larger than the surface roughness Ra of the central region by 0.2 nm or more is provided. The “central area” described in this specification refers to a region located at the center (center of gravity) of the second main surface of the glass substrate, and having a shape obtained by reducing the outline of the second main surface to a scale of 0.6 as a boundary. . In addition, the "outer peripheral region" refers to an area located on the outer periphery of the second main surface of the glass substrate, and the remaining region other than the central region among the second main surfaces. In addition, the surface roughness Ra of the central region is set at the central position of the central region, and the positions on the boundary between the outer peripheral region and the central region (eight locations of P1 to P8 shown in FIG. 1 in this specification). The average value of the measured arithmetic mean roughness was set to a position where the surface roughness Ra of the outer peripheral region was in a shape formed by moving each side portion forming the second main surface of the glass substrate by 10 mm toward the center region side (this In the description, the measurement is performed at eight places of P9 to P16 shown in FIG. 1). The “surface roughening region is provided” means that a surface roughness Ra that is 0.2 nm or more larger than the surface roughness Ra of the central region is displayed at any one of the measurement positions of the peripheral region.

As described above, in the present invention, the surface roughness Ra of the main surface (the first main surface) on one side of the glass substrate is set to such an extent that various elements, electrode wires, and electronic circuits can be formed with high accuracy. (0.2 nm or less), and on the other main surface (the second main surface), set the surface roughness Ra of the central region of the second main surface to 0.3 nm or more and 1.0 nm or less, and The outer peripheral region of the main surface is provided with a surface roughened region showing a surface roughness Ra that is 0.2 nm or more larger than the surface roughness Ra of the central region. Thereby, the surface roughened area located in the outer peripheral area becomes the starting point of peeling, and peeling can be started smoothly. Thereby, cracks in the glass substrate can be reduced, and the glass substrate can be peeled off safely. In addition, it is possible to reduce the problem that the glass substrate does not peel off from the mounting table due to the glass substrate being in close contact with the mounting table. Furthermore, as long as the surface roughness Ra of only one or more surface roughened regions included in the outer peripheral region shows a value of a predetermined size or more (a value of 0.2 nm or more greater than the surface roughness Ra of the central region), The glass substrate is sufficient, so that the process for roughening can be suppressed to a minimum area and amount. This enables roughening to be performed efficiently and at low cost.

In addition, in the glass substrate of the present invention, the surface roughened region may be extended along any one of the plurality of sides included in the second main surface, and the surface roughness Ra of the outer peripheral region may be increased as the distance from the surface is increased. One edge is reduced. In addition, "the surface roughened area extends along the edge part" means that the surface roughness Ra of a measurement position with a distance of 10 mm from a certain edge part is larger than the surface roughness Ra of the center area by 0.2 nm or more.

In this way, in the case where the surface roughened area is extended along any one of the edge portions, the surface roughness distribution of the outer peripheral area is set to decrease as the surface roughness Ra decreases away from the edge portion, thereby intentionally creating The direction in which the glass substrate is easily peeled off. Therefore, the glass substrate can be peeled off smoothly from the surface roughened area that becomes the starting point, and the glass substrate can be easily and safely peeled off.

In addition, in the glass substrate of the present invention, the surface roughened region may be provided on at least one of a plurality of corners included in the second main surface. The "surface roughened region is provided at the corner" refers to a measurement position at a vertex in a shape formed by moving each side portion forming the second main surface of the glass substrate by 10 mm toward the center region side. The surface roughness Ra is larger than the surface roughness Ra of the center region by 0.2 nm or more.

In this way, since the surface roughened region is provided on at least one corner of the four corners of the second main surface, this corner becomes the starting point of peeling, so that peeling of the glass substrate can be started smoothly.

In this case, in the glass substrate of the present invention, the surface roughened region may be provided at all corners of the plurality of corners.

In this way, since the surface roughened region is provided at all corners of the plurality of corners, all the corners become the starting point of peeling, so that the peeling of the glass substrate can be started smoothly.
[Effect of the invention]

As described above, according to the present invention, a glass substrate having a surface roughness distribution of a back surface suitable for an actual peeling operation can be obtained at low cost.

"First embodiment of the present invention"
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the glass substrate 1 of this embodiment is formed in a rectangular shape, for example, it is formed of silicate glass, silica glass, etc., preferably it is formed of borosilicate glass, and more preferably it is formed of alkali-free glass. . In this case, examples of the glass composition of the glass substrate 1 include SiO ₂ : 50% to 70%, Al ₂ O ₃ : 12% to 25%, and B ₂ O ₃ : 0 to 1% by mass. 12%, MgO: 0-8%, CaO: 0-15%, SrO: 0-12%, BaO: 0-15%.

In addition, the alkali-free glass mentioned here means the glass which does not substantially contain an alkali component (alkali metal oxide), and specifically means the glass whose alkali component is 3000 ppm or less. From the viewpoint of slightly preventing or reducing aging deterioration, glass having an alkali component of 1,000 ppm or less is more preferable, glass having an alkali component of 500 ppm or less, and even more preferably glass having an alkali component of 300 ppm or less.

The thickness dimension of the glass substrate 1 is set to, for example, 700 μm or less, preferably 600 μm or less, more preferably 500 μm or less, and even more preferably 400 μm or less. The reason is that the smaller the thickness dimension is, the more easily the glass substrate 1 is damaged in the peeling step, so the smaller the thickness dimension is, the more effectively the effects of the present invention can be enjoyed. In addition, the lower limit of the thickness dimension is not specifically set, but considering the handleability after forming (for example, handleability at the time of peeling, etc.), it is preferably set to 1 μm or more, and preferably 5 μm or more.

The area of the first main surface 2 of the glass substrate 1, that is, the area of the second main surface 3 (both refer to FIG. 2) is set to, for example, 0.09 m ² or more, preferably 0.2 m ² or more, and more preferably 0.5. m ² or more, and more preferably 1.0 m ² or more. This is because there is a tendency that the larger the area of the second main surface 3 is, the more easily the peeling and charging are caused, and the charging amount at this time also increases. Therefore, the larger the area of the second main surface 3 is, the more effectively the effects of the present invention can be enjoyed. In addition, the upper limit of the area is not particularly set, but considering the handleability after molding, especially the handleability during surface treatment, etc., the area of the second main surface 3 is set to, for example, 10 m ² or less, and is preferably set to 6.5 m ² or less.

Next, the surface properties, especially the surface roughness, of the glass substrate 1 will be described.

The surface roughness Ra of the first main surface 2 of the glass substrate 1 is 0.2 nm or less. The surface roughness Ra described here is measured and evaluated by an atomic force microscope based on the arithmetic average roughness of (Japanese Industrial Standards, JIS) R 1683: 2014 (hereinafter, the same in this specification).

FIG. 2 shows an example of the distribution of the surface roughness Ra of the second main surface 3 of the glass substrate 1. In FIG. 2, the height of the histogram indicates the size of the surface roughness Ra, and the numbers or symbols in parentheses described above or to the side of the histogram indicate the second main surface 3 of the glass substrate 1 shown in FIG. 1. Position (see Figure 1). As shown in FIG. 2, the surface roughness Ra of the second main surface 3 is different in the central region 4 and the outer peripheral region 5. Specifically, as shown in FIG. 2, the surface roughness Ra of the central region 4 of the second main surface 3 is 0.3 nm or more and 1.0 nm or less. In contrast, in the outer peripheral region 5 of the second main surface 3, A surface roughened region A showing a surface roughness Ra that is larger than the surface roughness Ra of the center region 4 by 0.2 nm or more is provided.

Here, as shown in FIG. 1, the central region 4 refers to a region located at the center (center of gravity) of the second main surface 3 and having a shape obtained by reducing the outline of the second main surface 3 to a scale of 0.6. . The center of gravity of the second main surface 3 coincides with the center of gravity of the shape obtained by reducing the outline of the second main surface 3 by a scale of 0.6. The outer peripheral region 5 refers to a region remaining in the second main surface 3 other than the central region 4 defined as described above.

In addition, in the present specification, the surface roughness Ra of the central region 4 is set at the central position P0 of the central region 4 and the position on the boundary 10 between the outer peripheral region 5 and the central region 4 (in this specification, as shown in FIG. 1 The corners P1 to P4 of the boundary 10 and the average positions of the arithmetic mean roughnesses measured at the corners P1 to P4 (the intermediate positions P5 to P8 of the corners P4 to P8) are shown. In addition, corner portions P9 to P12 of a shape formed by moving each side portion 6 to 9 forming the second main surface 3 of the glass substrate 1 toward the center region side by 10 mm, and each side portion 6 'of the shape. The surface roughness Ra of the peripheral region 5 was measured and evaluated at the intermediate position P13 to P16 to 9 ′.

The so-called "surface roughened region A provided with a surface roughness Ra that is 0.2 nm or more greater than the surface roughness Ra of the central region 4 in the outer peripheral region 5 of the second main surface 3" means the outer peripheral region 5 Any of the arithmetic mean roughness values at the measurement positions P9 to P16 is 0.2 nm or more larger than the surface roughness Ra (average value of P1 to P8) of the center region 4.

In addition, in this embodiment, as shown in FIG. 2, the surface roughened region A is extended along one short side portion 8 of the plurality of side portions 6 to 9 included in the second main surface 3. Here, the "surface roughened region A extends along one of the plurality of side portions 6 to 9 of the second main surface 3" refers to a side portion that is moved 10 mm toward the center region 4 side The surface roughness Ra of the measurement position P9, the measurement position P11, and the measurement position P14 at 8 'is larger than the surface roughness Ra (average value of P1 to P8) of the central region 4 by 0.2 nm or more.

In this embodiment, as shown in FIG. 2, the surface roughness Ra of the outer peripheral region 5 decreases as it goes away from the one short side portion 8. Therefore, in the outer peripheral region 5, the surface roughness Ra of P10, P12, and P15 is smaller than the surface roughness Ra of the central region 4. That is, a region having a smaller surface roughness Ra than the center region 4 is provided in parallel to the surface roughened region A with the center region 4 interposed therebetween.

From the viewpoint of the ease of peeling, the larger the surface roughness Ra of the surface roughened region A, the better, but if it becomes too large, it will take more time than necessary for the surface treatment described later. In addition, a pitch deviation is likely to occur during the heat treatment in the manufacturing process of the FPD. In view of the above, the surface roughness Ra of the surface roughened region A is preferably set to a surface roughness Ra + 0.5 nm or less of the central region 4, and is preferably set to a surface roughness Ra + 0 of the central region 4. 3 nm or less is preferred.

The glass substrate 1 having the above-mentioned structure is obtained by cutting a glass substrate formed into a strip shape by a known molding method typified by various down-draw methods to a predetermined size in the longitudinal direction, and After the both ends of the width direction of the glass substrate obtained after cutting are further cut, if necessary, grinding, polishing, etc. are performed on each cut surface. In addition, as various pull-down methods, an overflow pull-down method is mentioned as a suitable example. According to the overflow down-draw method, the first main surface 2 of the glass substrate becomes a forged surface, and its surface roughness Ra can be easily made 0.2 nm or less.

The distribution of the surface roughness Ra of the second main surface 3 serving as the back surface of the glass substrate 1 can be obtained, for example, by providing a surface treatment step shown below after the end surface processing step.

FIG. 3 shows a surface treatment step 20 for imparting a distribution of the surface roughness Ra shown in FIG. 2 to the second main surface 3. The surface treatment step 20 includes: a transfer device 21 for transferring the glass substrate 1 in a predetermined direction X1; and a surface treatment device 22 for the second main surface 3 of the glass substrate 1 transferred by the transfer device 21 (if shown in FIG. 3) In the case of the lower surface, a predetermined surface treatment is performed; and the processing chamber 23 houses the transport device 21 and the surface treatment device 22.

Among them, the conveying device 21 includes, for example, a plurality of pairs of rollers 24, and at least a part of the plurality of pairs of rollers 24 is rotationally driven to convey the glass substrate 1 on the rollers 24 in a predetermined direction X1. When there are remaining rollers 24 that are not rotationally driven, the remaining rollers 24 are so-called free rollers. Furthermore, in FIG. 3, a plurality of pairs of rollers 24 are arranged before and after the conveyance direction X1 of the surface treatment device 22, but may be disposed on the insertion pipe 25 of the surface treatment device 22 as necessary.

The surface treatment device 22 is a person for supplying a processing gas G to the second main surface 3 of the glass substrate 1 to perform a predetermined surface treatment. The surface treatment device 22 includes a pipe 25 for inserting the glass substrate 1 to be processed; One or more air supply ports 26 are opened in the plug-in pipe 25; one or more air outlets 27 are opened in the plug-in pipe 25 at a position different from the air supply port 26; a processing gas generating device 28. A process gas G is generated; and an exhaust treatment device 29 is used to render the used process gas G harmless. The process gas generating device 28 is connected to the air supply port 26 via the gas supply line 30, and the exhaust gas processing device 29 is connected to the exhaust port 27 via the exhaust line 31.

The type and composition of the processing gas G are arbitrary as long as a predetermined surface treatment (roughening by corrosion) can be performed on the glass substrate 1. For example, an acidic gas such as hydrogen fluoride gas, or a portion containing such a gas can be used.

In the surface processing step 20 of the structure, the processing gas G generated by the processing gas generating device 28 is introduced into the gas supply line 30 and is released from the gas supply port 26 located at the downstream end of the gas supply line 30. If the glass substrate 1 (indicated by the two-dot chain line in FIG. 3) shown in FIG. 1 is inserted into the insertion pipe 25 facing the air supply port 26, the processing gas that has been released from the air supply port 26 G is in contact with the second main surface 3 of the glass substrate 1, and a predetermined surface treatment is performed on the second main surface 3. Thereby, the second main surface 3 of the glass substrate 1 is corroded and roughened.

At this time, by appropriately setting the surface treatment conditions, the distribution of the surface roughness Ra shown in FIG. 2 can be imparted to the second main surface 3. Specifically, the glass substrate 1 is transported in a horizontal posture in a state where the longitudinal direction of the long side portion 6 and the long side portion 7 of the glass substrate 1 coincides with the transport direction X1 (see FIG. 3). Thereby, the side of the short side portion 8 (FIG. 1) is turned into a row head, and the glass substrate 1 is introduced into the insertion pipe 25. In addition, as the introduction of the glass substrate 1 into the insertion line 25 is started, the conveyance speed of the glass substrate 1 is gradually increased, and / or the supply to the second main surface 3 in the insertion line 25 is gradually decreased. The flow rate of the process gas G is controlled. By setting various surface treatment conditions in this way, the surface roughened region A can be given to the second main surface 3 to extend along one short side portion 8 (FIG. 1), and the surface roughness Ra of the outer peripheral region 5 becomes longer away from one short side. The distribution of the surface roughness Ra reduced by the portion 8.

In addition, the processing gas G that has been supplied to the glass substrate 1 is introduced into the exhaust line 31 through the exhaust ports 27 (two in this embodiment) facing the insertion line 25 and is introduced into the exhaust line 31. In the exhaust treatment device 29 on the downstream side of the exhaust line 31. The introduced processing gas G is discharged to the outside of the system in a state where harmful substances are removed by the exhaust treatment device 29.

As described above, in the glass substrate 1 of the present invention, the surface roughness Ra of the first main surface 2 is set to a level at which various elements, electrode lines, and electronic circuits can be formed with high accuracy (0.2 nm or less). , On the second main surface 3, set the surface roughness Ra of the central region 4 of the second main surface 3 to 0.3 nm or more and 1.0 nm or less, and set a display in the outer peripheral region 5 of the second main surface 3 A surface roughened region A having a surface roughness Ra larger than the surface roughness Ra of the center region 4 by 0.2 nm or more is obtained. Thereby, the surface roughening area A located in the outer peripheral area 5 becomes a starting point of peeling, and peeling can be started smoothly. Thereby, cracks in the glass substrate 1 can be reduced, and the glass substrate 1 can be peeled off safely. In addition, it is possible to reduce the problem that the glass substrate 1 does not peel off from the mounting table due to the glass substrate 1 being in close contact with the mounting table. Furthermore, as long as the surface roughness Ra of only one or more of the surface roughened regions A included in the outer peripheral region 5 shows a value greater than a predetermined size (a value that is 0.2 nm or more larger than the surface roughness Ra of the central region 4) ) Can be used as the glass substrate 1, and therefore, the roughening treatment, such as the surface treatment using the processing gas G shown in FIG. 3, can be suppressed to a minimum area and amount. This enables roughening to be performed efficiently and at low cost.

In addition, in this embodiment, the distribution of the surface roughness Ra in which the surface roughened region A is extended along the side portion 8 and the surface roughness Ra of the outer peripheral region 5 decreases as it moves away from the side portion 8 is set at the first Two major surfaces 3. In this way, by providing a predetermined weight along the long side portion 6 and the long side portion 7 in the distribution of the surface roughness Ra, it is possible to intentionally create a direction in which the glass substrate 1 is easily peeled off (here, along the long side). Part 6, long side part 7). Therefore, it is easy to peel off along the long side portion 6 and the long side portion 7 from the short side portion 8 in the surface roughened region A which is the starting point, and the glass substrate 1 can be easily and safely peeled off.

The first embodiment of the present invention has been described above, but the glass substrate of the present invention is not limited to the above embodiment, and various forms can be adopted within the scope of the present invention.

"Second Embodiment of the Invention"

FIG. 4 shows an example of the distribution of the surface roughness Ra of the second main surface 3 of the glass substrate 1 according to the second embodiment of the present invention. In FIG. 4, the height of the histogram indicates the size of the surface roughness Ra, and the numbers or symbols in parentheses described above or to the side of the histogram indicate the second major surface 3 of the glass substrate 1 shown in FIG. 1. On location. As shown in FIG. 4, in the present embodiment, a rough surface having a surface roughness Ra that is 0.2 nm or more greater than the surface roughness Ra of the central region 4 is also provided in the outer peripheral region 5 of the second main surface 3.化 区 A。 Area A.

In addition, in the present embodiment, in addition to the above-mentioned structure, a surface in which the surface roughened region A is extended along the long side portion 7 and the surface roughness Ra of the outer peripheral area 5 decreases as it goes away from the long side portion 7 Distribution of roughness Ra. That is, the direction in which the surface roughened region A extends in the present embodiment and the direction in which the surface roughness Ra of the outer peripheral region 5 changes are different from those in the first embodiment.

The distribution of the surface roughness Ra of the second main surface 3 as shown in FIG. 4 can be obtained, for example, by providing a surface treatment step shown below after the end surface processing step.

FIG. 5 shows a surface treatment step 40 for imparting a distribution of the surface roughness Ra shown in FIG. 4 to the second main surface 3. As in FIG. 3, the surface treatment step 40 includes a conveying device 41 for conveying the glass substrate 1 in a predetermined direction X1, a surface treatment device 42, and a processing chamber 43 that houses the conveyance device 41 and the surface treatment device 42.

Among them, the conveying device 41 includes a pair of rollers 44 and 45. The rotation axes of the pair of rollers 44 and 45 are inclined with respect to the horizontal plane. Thereby, the glass substrate 1 can be conveyed in the predetermined direction X1 in a state where the glass substrate 1 is tilted such that the long side portion 7 side is positioned lower than the long side portion 6 side.

In this case, the glass substrate 1 can be inserted into the insertion pipe 46 in a state in which the glass substrate 1 is inclined along the short side portion 8 and the short side portion 9, and the first roller 44 side is positioned more than the second roller. At a position further below the 45 side, the posture of the insertion pipe 46 of the surface treatment device 42 is inclined. The other structures are the same as those of the surface treatment device 22 shown in FIG. 3, and thus detailed descriptions are omitted.

In the surface processing step 40 of the structure, the processing gas G generated by the processing gas generating device 28 (FIG. 3) is introduced into the gas supply pipe 30 (FIG. 3), and is located at the downstream end of the gas supply pipe 30. The air supply port 47 (Fig. 5) is released. If the glass substrate 1 (indicated by the two-dot chain line in FIG. 5) shown in FIG. 1 is inserted into the insertion pipe 46 facing the air supply port 47, the processing gas that has been released from the air supply port 47 G is supplied to the second main surface 3 of the glass substrate 1, and a predetermined surface treatment is performed on the second main surface 3. Thereby, the second main surface 3 of the glass substrate 1 is corroded and roughened.

At this time, by appropriately setting the surface treatment conditions, the distribution of the surface roughness Ra shown in FIG. 4 can be imparted to the second main surface 3. Specifically, the longitudinal direction of the long side portion 6 and the long side portion 7 of the glass substrate 1 is aligned with the conveyance direction X1 (see FIG. 3), and the long side portion 7 side is positioned more than the long side portion 6 side. In the downward mode, the glass substrate 1 is transported while being inclined, and the processing gas G is supplied to the second main surface 3 (FIG. 5). By setting the main surface treatment conditions in this way, the more the area below the second main surface 3, the more the degree of roughening becomes higher, and the more the area above the second main surface 3, the more the degree of roughening is. The more the relative decline. Thereby, in the glass substrate 1 obtained through the surface treatment step 40, the second main surface 3 can be provided with a surface roughened area A extending along the long side portion 7 and an outer peripheral area 5 as shown in FIG. 4. The distribution of the surface roughness Ra that decreases as the distance from the long side portion 7 decreases.

In this way, in the present embodiment, the distribution of the surface roughness Ra in which the surface roughened region A is extended along the long side portion 7 and the surface roughness Ra of the outer peripheral region 5 decreases as it moves away from the long side portion 7 is provided. In the second main surface 3. In this way, by providing a predetermined weight along the short-side portion 8 and the short-side portion 9 in the distribution of the surface roughness Ra, the direction in which the glass substrate 1 is easily peeled off (here, along the short-side portion 8, The direction of the short side portion 9) is created in a direction different from that of the first embodiment. Therefore, it is easy to peel off along the short-side portion 8 and the short-side portion 9 from the long-side portion 7 in the surface roughened region A which is the starting point, and the glass substrate 1 can be easily and safely peeled off.

"Third Embodiment of the Invention"
FIG. 6 shows an example of the distribution of the surface roughness Ra of the second main surface 3 of the glass substrate 1 according to the third embodiment of the present invention. In FIG. 6, the height of the histogram indicates the size of the surface roughness Ra, and the numbers or symbols in parentheses described above or to the side of the histogram indicate the second main surface 3 of the glass substrate 1 shown in FIG. 1. On location. As shown in FIG. 6, in this embodiment, a rough surface having a surface roughness Ra that is 0.2 nm or more larger than the surface roughness Ra of the center region 4 is also provided in the outer peripheral region 5 of the second main surface 3.化 区 A。 Area A.

In addition, in the present embodiment, the surface roughened region A is provided at one corner of the four corners forming the second main surface 3. The "surface roughened region A is provided at the corner" refers to the measurement positions P9 to P12 at the apex of the shapes 6 'to 9' formed by moving each side portion 6 to 9 to the center region side by 10 mm. Any one of the surface roughness Ra is larger than the surface roughness Ra of the center region 4 by 0.2 nm or more (see FIG. 1). In the glass substrate 1 shown in FIG. 6, a surface roughened area A is provided at a corner (measurement position P11) at the lower left.

The distribution of the surface roughness Ra of the second main surface 3 as shown in FIG. 6 can be obtained, for example, by performing various processes on the glass substrate 1 according to the flow shown in FIG. 7.

Specifically, as shown in FIG. 7, first, the glass substrate 1 is subjected to a surface treatment using a processing gas G in a surface treatment step 20 shown in FIG. 3, thereby roughening the entire area of the second main surface 3. (First roughening step S1). Then, masking is performed on an area other than a predetermined corner portion (here, a corner portion including a position P11 shown in FIG. 1) of the second main surface 3 of the glass substrate 1 (masking step S2). Then, the masked glass substrate 1 is subjected to the surface treatment of the surface treatment step 20 shown in FIG. 3 again, thereby roughening only the predetermined corner portions that are not masked (second roughening step S3). . Thereby, the surface roughness Ra of the surface roughened region A provided at the predetermined one of the four corners (including the corner of the position P11) among the four corners forming the second main surface 3 can be imparted to the second main surface 3. Distribution.

As described above, in the present embodiment, the surface roughened area A is provided in at least one of the four corners of the second main surface 3, so the corner portion P11 located in the surface roughened area A becomes the starting point of peeling. Therefore, peeling of the glass substrate 1 can be started smoothly.

"Fourth embodiment of the present invention"
FIG. 8 shows an example of the distribution of the surface roughness Ra of the second main surface 3 of the glass substrate 1 according to the fourth embodiment of the present invention. In FIG. 8, the height of the histogram indicates the magnitude of the surface roughness Ra, and the numbers or symbols in parentheses described above or to the side of the histogram indicate the second main surface 3 of the glass substrate 1 shown in FIG. 1. On location. As shown in FIG. 8, in this embodiment, a rough surface having a surface roughness Ra that is 0.2 nm or more larger than the surface roughness Ra of the center region 4 is also provided in the outer peripheral region 5 of the second main surface 3.化 区 A。 Area A.

In addition, in the present embodiment, the surface roughened region A is provided at all four corner portions forming the second main surface 3. In the glass substrate 1 shown in FIG. 8, the surface roughness Ra of the measurement positions P9 to P12 is larger than the surface roughness Ra of the center region 4 by 0.2 nm or more, and surface roughening is provided at all four corners. Area A (Figure 8).

The distribution of the surface roughness Ra of the second main surface 3 as shown in FIG. 8 can be obtained by performing various processes on the glass substrate 1 according to the flow shown in FIG. 9, for example.

Specifically, as shown in FIG. 9, first, the glass substrate 1 is subjected to a surface treatment using a processing gas G in a surface treatment step 20 shown in FIG. 3, thereby roughening the entire area of the second main surface 3. (First roughening step S4). Then, the second main surface 3 of the glass substrate 1 is masked except for all four corners (here, corners including positions P9 to P12 shown in FIG. 1) (blocking step S5). . Then, the masked glass substrate 1 is subjected to the surface treatment of the surface treatment step 20 shown in FIG. 3 again, thereby roughening again only all four corners that are not masked (second roughening step S6). ). Thereby, the distribution of the surface roughness Ra of the surface roughened area A provided at all four corner portions forming the second main surface 3 can be imparted to the second main surface 3.

In this way, in this embodiment, since the surface roughened area A is provided at all four corners of the second main surface 3, all the corners P9 to P12 located in the surface roughened area A become the starting points of peeling, so that The peeling started smoothly.

Furthermore, in the third embodiment, a case where the surface roughened area A is provided in a predetermined corner is exemplified, and in the fourth embodiment, the surface roughened area A is provided in all four corners. In the case of course, it is of course possible to give the second main surface 3 a distribution of the surface roughness Ra provided with the surface roughened region A at two or three corners.

In the third and fourth embodiments, the surface roughness Ra of the region other than the corners in the outer peripheral region 5 is arbitrary. Therefore, for example, positions P13 to P16 shown in FIG. 1 may be used. The distribution of all or a part of the surface roughness Ra is larger than the surface roughness Ra of the central region 4 by 0.2 nm or more. As described above, if the outer peripheral edge of the outer peripheral region 5, that is, all the outer peripheral edge of the second main surface 3 is the surface roughened region A, peeling can be started more smoothly.

In addition, in the first embodiment, the distribution of the surface roughness Ra shown in FIG. 2 is given to the second main surface 3 by adjusting the conveyance speed of the glass substrate 1 or the supply flow rate of the process gas G, as an example. In the second embodiment, a case is shown in which the surface shown in FIG. 4 is given to the second main surface 3 by carrying out surface treatment while the glass substrate 1 is tilted in a predetermined direction while being conveyed in the second embodiment. Distribution of roughness Ra, but these distributions can also be formed by methods other than those described above. That is, although the illustration is omitted, the glass substrate 1 is transported in a horizontal posture while the long-side direction of the short-side portion 8 and the short-side portion 9 is aligned with the transport direction X1, as in the first embodiment. The distribution rate of the surface roughness Ra shown in FIG. 4 can also be imparted to the second main surface 3 by appropriately setting the conveying speed or the supply flow rate of the processing gas G. Alternatively, although the illustration is also omitted, the long-side direction of the short-side portion 8 and the short-side portion 9 is aligned with the conveying direction X1, and the short-side portion 8 side is positioned below the short-side portion 9 side. The glass substrate 1 is transported while being inclined, and while the processing gas G is supplied to the second main surface 3, the second main surface 3 may be provided with a distribution of surface roughness Ra as shown in FIG. 2.

Alternatively, the distributions of the surface roughness Ra of the first and second embodiments may be formed by methods other than those described above. For example, although illustration is omitted, a cleaning step for cleaning the glass substrate 1 with water or the like is provided as a pre-step of the surface treatment step 20 and the surface treatment step 40, and the moisture attached to the second main surface 3 during cleaning is set A predetermined biased state is set. At this time, for example, the more the moisture is attached to the short side portion 8 side, and the shorter the short side portion 9 side is, the less the moisture is attached. After attaching more weight to the moisture attachment state, the implementation is shown in FIG. 3 As a result, the distribution of the surface roughness Ra shown in FIG. 2 can be imparted to the second main surface 3. Alternatively, the more the moisture is attached to the side of the long side portion 7 and the less the moisture is attached to the side of the long side portion 6, the surface of the attached state of the moisture is weighted, and then the surface shown in FIG. 3 is implemented. Processing, whereby the distribution of the surface roughness Ra shown in FIG. 4 can be imparted to the second main surface 3. In this case, it is estimated that the degree of surface treatment (roughening) using the processing gas G changes depending on the degree of adhesion of moisture. Therefore, if the glass substrate 1 is subjected to surface treatment in a state where the weight is attached as described above, it is not necessary to change the conveyance speed, the supply flow rate of the process gas G, or the conveyance posture of the glass substrate 1. That is, even when the conveyance speed or the supply flow rate of the process gas G is fixed and the glass substrate 1 is conveyed in a horizontal posture, the distribution of the surface roughness Ra shown in FIG. 2 or FIG. 4 may be provided. Of course, if no pre-cleaning is required, it is only necessary to set the weight of the attached state of the moisture on the second main surface 3, and set the moisture to be, for example, misty before the surface treatment step 20 and the surface treatment step 40. Supply steps.

Of course, as long as the surface roughness Ra of the central region 4 of the second main surface 3 is 0.3 nm or more and 1.0 nm or less, a peripheral surface 5 having a surface roughness Ra that is 0.2 nm or more larger than the surface roughness Ra of the central region 4 is provided. The surface roughened area A of the surface roughness Ra is arbitrary as a method for imparting the distribution of the surface roughness Ra to the second main surface 3.

In addition, although the glass substrate 1 of the first to fourth embodiments is not shown, it is possible to raise the pins provided on a plurality of positions of the mounting table when the FPD is manufactured, thereby self-mounting the table. A form in which the glass substrate 1 is peeled off. In this case, even if a plurality of pins are raised at the same time, the surface roughened area A located in the outer peripheral area 5 becomes a starting point and peeling can be started smoothly, but it is preferable that the surface roughened area A is located among the plurality of pins. Sales in China rose first. When the pin rate in the surface roughened area A or its periphery is raised first, the surface roughened area A becomes a starting point more surely, so that peeling can be started more smoothly. In addition, it is preferable to raise the pins in order of a short distance from the surface roughened area A as the starting point. When the pins are raised in the order of the distance from the surface roughened area A as the starting point, peeling of the starting point can be performed more smoothly.
[Example]

As an example of the present invention, 1,000 glass substrates were manufactured. The glass substrate was an alkali-free glass substrate (product name: OA-11) for displays manufactured by Nippon Electric Glass Co., Ltd. The size of the glass substrate was 2200 mm × 2500 mm, and the thickness was 50 μm. The forming method was an overflow down-draw method. The second main surface of the glass substrate was subjected to a surface treatment using a surface treatment step shown in FIG. 5.

One glass substrate was selected from the manufactured glass substrates, and the surface roughness Ra of the second main surface was measured using a measuring device (manufactured by Bruker, model: Dimension ICON). As a result, the surface roughness Ra (average value of P0 to P8) in the center region was 0.4 nm. The surface roughness Ra in the peripheral region is 0.3 nm at P9, 0.3 nm at P10, 0.6 nm at P11, 0.6 nm at P12, 0.3 nm at P13, 0.4 nm at P14, and 0.4 nm at P15 and 0.6 nm at P16. Therefore, the second main surface 3 of the glass substrate is provided with a surface roughened region A extending along the long side portion 7 as shown in FIG. 4, and the surface roughness Ra of the outer peripheral region 5 increases as the distance from the long side portion 7 increases. The distribution of reduced surface roughness Ra. The obtained glass substrate was subjected to a peeling test. In the peeling test, after being placed on the mounting table, a plurality of pins included in the mounting table were simultaneously raised to thereby peel the glass substrate from the mounting table.

In the comparative example, a glass substrate was manufactured under the same conditions as in the example except that the second main surface of the glass substrate was subjected to surface treatment in a horizontal posture. As a result, the surface roughness Ra (average value of P0 to P8) in the center region was 0.4 nm. The surface roughness Ra of the peripheral region (P9 to P16) is 0.3 nm to 0.5 nm. Therefore, the surface roughened area A is not formed in the second main surface of the glass substrate. This glass substrate was subjected to a peeling test.

In the peel test of the comparative example, 50 glass substrates among 1000 glass substrates did not peel off from the mounting table even if the pins were raised. On the other hand, in the peel test of the example, all 1000 glass substrates were peeled from the mounting table with the rise of the pins. That is, the problem that the glass substrate does not peel off from the mounting table can be suppressed. Therefore, according to the glass substrate of the present invention, it can be confirmed that the surface roughened region A located in the outer peripheral region can be used as a starting point, and peeling can be started smoothly.

1‧‧‧ glass substrate

2‧‧‧ first major surface

3‧‧‧Second major surface

4‧‧‧ central area

5‧‧‧ peripheral area

6 ～ 9, 6 '～ 9'‧‧‧Edge

10‧‧‧ border

20, 40‧‧‧ Surface treatment steps

21, 41‧‧‧ transport device

22, 42‧‧‧ Surface treatment equipment

23, 43‧‧‧ treatment room

24‧‧‧roller

25, 46‧‧‧ Plug in the pipeline

26、47‧‧‧Air supply port

27‧‧‧ exhaust port

28‧‧‧Processing gas generating device

29‧‧‧ exhaust treatment device

30‧‧‧Gas supply pipeline

31‧‧‧ exhaust pipe

44‧‧‧roller / first roll

45‧‧‧roller / second roller

A‧‧‧ surface roughened area

G‧‧‧Processing gas

P0‧‧‧central position

P1 ～ P4‧‧‧Corner

P5 ～ P8‧‧‧‧Middle position

P9 ～ P12‧‧‧corner / measurement position

P13 ～ P16‧‧‧Intermediate position / Measurement position

Ra‧‧‧ Surface roughness

S1 ～ S6‧‧‧‧steps

X1‧‧‧ direction

FIG. 1 is a plan view of a glass substrate according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically depicting a surface roughness distribution in a second main surface of the glass substrate shown in FIG. 1.

FIG. 3 is a diagram for explaining an example of a method for manufacturing the glass substrate shown in FIG. 1, and is a schematic front view of a step of subjecting a second main surface of the glass substrate to a surface treatment.

FIG. 4 is a view schematically depicting a surface roughness distribution in a second main surface of a glass substrate according to a second embodiment of the present invention.

FIG. 5 is a diagram for explaining an example of a method for manufacturing the glass substrate shown in FIG. 4, and is a schematic side view in a direction orthogonal to the conveyance direction in the step of subjecting the second main surface of the glass substrate to a surface treatment process.

FIG. 6 is a diagram schematically depicting a surface roughness distribution in a second main surface of a glass substrate according to a third embodiment of the present invention.

FIG. 7 is a flowchart for explaining an example of a method for manufacturing the glass substrate shown in FIG. 6.

8 is a view schematically depicting a surface roughness distribution in a second main surface of a glass substrate according to a fourth embodiment of the present invention.

FIG. 9 is a flowchart for explaining an example of a method for manufacturing the glass substrate shown in FIG. 8.

Claims (4)

A glass substrate is a glass substrate including a first main surface and a second main surface, and is characterized in that: The surface roughness Ra of the first main surface is 0.2 nm or less, The surface roughness Ra of the central region of the second main surface is 0.3 nm or more and 1.0 nm or less, In the outer peripheral region of the second main surface, a surface roughened region showing a surface roughness Ra that is larger than the surface roughness Ra of the central region by 0.2 nm or more is provided. The glass substrate according to item 1 of the patent application scope, wherein the surface roughened region is extended along any one of a plurality of sides of the second main surface, and the surface of the outer peripheral region The roughness Ra decreases as it goes away from the one edge portion. The glass substrate according to item 1 of the scope of patent application, wherein the surface roughened region is provided on at least one of a plurality of corners of the second main surface. The glass substrate according to item 3 of the scope of patent application, wherein the surface roughened region is provided at all corners of the plurality of corners.