Glass substrate and method for manufacturing electronic device

Abstract

This rectangular glass substrate 1 has first edges 1y parallel to a sheet-pulling direction Y and second edges 1x parallel to a width direction X. The length of the second edges 1x is 1500 mm or more. The thickness of the glass substrate is 1.3 mm or less. When seven rectangular evaluation regions A, B, C, D, E, F, and G having the same size are sequentially set from one end side in the width direction X so as to obtain a positional relationship in which the respective regions are separated by an equal interval L in the width direction X, the average ΔHC-E of obverse-reverse flexure difference Y1-Y2 of the evaluation regions C, D, and E in the sheet-pulling direction Y is negative.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a glass substrate and an electronic device. [Background technology]

[0002] The manufacturing process of electronic devices such as panel displays (e.g., liquid crystal displays, organic electroluminescence displays) includes a film-forming process in which multiple thin film patterns are formed on a glass substrate (mother glass) by photolithography. These thin film patterns have become more complex and dense as panel displays have become more highly refined (e.g., Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-74582 [Patent Document 2] International Publication No. 2017 / 150266 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, thin film patterns (e.g., gate electrode patterns) formed on glass substrates are evaluated using an index called total pitch. The total pitch is an index of whether the thin film pattern is regulated as designed, and is controlled, for example, by the difference between the designed distance and the measured distance between two predetermined points marked with control marks. If this difference in total pitch (hereinafter referred to as "total pitch deviation") becomes too large, it means that the thin film pattern is formed in a state that significantly deviates from the design, which can result in a decrease in the pixel aperture ratio, light leakage between pixels, and other problems, which can significantly degrade the quality of the electronic device.

[0005] One cause of the large total pitch deviation is irregular positional deviation of the glass substrate when it is placed in the exposure tool during the thin-film pattern deposition process. Specifically, glass substrates are not ideally flat, and their shape deviates slightly from the ideal plane due to the effects of annealing conditions. Therefore, if the glass substrate has an improper shape, the force that deforms the glass substrate to conform to the suction platen during the process of adsorbing the glass substrate onto the suction platen of the exposure tool is applied in an inappropriate direction, causing the glass substrate to fluctuate irregularly. Exposure in this state results in large exposure errors, resulting in large total pitch deviations of the thin-film pattern formed on the glass substrate. Furthermore, in the color filter process, in which a black matrix (BM) film is applied to the glass substrate, patterning is performed with a photomask, and then a three-color RGB filter is applied, pattern deviations during the formation of higher-resolution displays can result in color variations (ununiformity) in the final screen display.

[0006] An object of the present invention is to provide a glass substrate capable of reliably reducing the total pitch deviation of thin film patterns, and to provide an electronic device including a glass substrate in which the total pitch deviation of thin film patterns is reliably reduced. [Means for solving the problem]

[0007] (a) The present invention, which has been invented to solve the above-mentioned problems, relates to a rectangular glass substrate having a first side along the drawing direction and a second side along the width direction perpendicular to the drawing direction, the length of the second side being 1500 mm or more and a thickness being 1.3 mm or less, one of whose main surfaces is a guaranteed surface, and in which seven rectangular evaluation areas A, B, C, D, E, F, and G of the same size are set in order from one end side in the width direction, the average value ΔH of the front-to-back deflection difference in the drawing direction of the central evaluation areas C, D, and E is calculated by the following formula (1): C-E is negative. Difference in front and back deflection = (Y1-Y2) [mm] (1) Y1: Deflection in the sheet drawing direction when the guaranteed surface of the sample glass corresponding to the evaluation area for measuring the difference in deflection between the front and back surfaces is facing downwards Y2: Deflection in the sheet drawing direction when the guaranteed surface of the sample glass corresponding to the evaluation area where the difference in deflection between the front and back surfaces is measured is facing upward.

[0008] With this configuration, when the glass substrate is oriented with the guaranteed side facing upward, the central portion of the width direction corresponding to the evaluation areas C, D, and E has a bowl-like shape in the drawing direction. Here, when any linear region (cross section) of the glass substrate is viewed along the drawing direction, the linear region is drawn through the same location during annealing. In other words, the annealing conditions, such as the thermal history, of the linear region along the drawing direction are substantially the same regardless of the position in the drawing direction. Therefore, if the position in the width direction is the same, the shape in the drawing direction will show substantially the same tendency. Therefore, with the above configuration, when the glass substrate is oriented with the guaranteed side facing upward, the central portion of the width direction has a bowl-like shape along the drawing direction not only within the range of the evaluation area but also over substantially the entire length in the drawing direction. With such a bowl-like glass substrate, when the non-guaranteed side behind the guaranteed side is suctioned by a suction plate, suction proceeds smoothly from the central portion in the drawing direction toward the ends in the drawing direction, thereby suppressing misalignment. In other words, it is possible to reliably reduce the total pitch deviation of the thin film pattern formed on the guaranteed surface of the glass substrate.

[0009] (b) In the configuration of (a) above, the average value ΔH of the difference in front and back deflection in the sheet pulling direction for evaluation areas A, B, C, D, E, F, and G A-G is preferably negative.

[0010] In this way, the glass substrate has a bowl-like shape across almost the entire width direction and across almost the entire length in the drawing direction, which further reduces positional deviation of the glass substrate when the non-supported surface of the glass substrate is chucked by the chuck surface plate, thereby further reducing the total pitch deviation of the thin film pattern.

[0011] (c) In the configuration of (a) or (b) above, the difference in front and back deflection in the drawing direction of the evaluation areas A, B, C, D, E, F, and G is calculated as ΔH A ,ΔH B ,ΔH C ,ΔH D ,ΔH E ,ΔH F ,ΔH G When this is the case, ΔH A ~ΔH G At least ΔH C ,ΔH D ,ΔH E are preferably negative.

[0012] This reduces the change in shape within the glass substrate surface, resulting in a bowl-like shape with a smooth change in shape. Therefore, when the non-supported surface of the glass substrate is chucked by the chuck surface plate, the occurrence of positional deviation of the glass substrate can be further suppressed, and the total pitch deviation of the thin film pattern can be further reduced.

[0013] (d) In any of the configurations (a) to (c) above, the maximum value ΔH of the difference in front and back deflection in the sheet pulling direction among the evaluation areas A, B, C, D, E, F, and G max and the minimum value ΔH of the difference in front and back deflection in the sheet pulling direction among the evaluation areas A, B, C, D, E, F, and G. min Difference ΔH max -ΔH min However, it is preferable that the thickness is 0.5 mm or less.

[0014] This reduces the variation in the difference in the warp between the front and back surfaces in the drawing direction. In other words, it is possible to suppress large changes in the shape of the glass substrate in the drawing direction, which in turn prevents insufficient or insufficient suction when the non-reliable surface of the glass substrate is suctioned by the suction plate. This therefore contributes to reducing the total pitch deviation of the thin film pattern.

[0015] (e) In any of the configurations (a) to (d) above, the average value ΔV of the difference in front and back deflection in the width direction of the central evaluation areas C, D, and E calculated by the following formula (2) C-E But, ΔVC-E It is preferred that ≦0. Difference in front and back deflection = (X1-X2) [mm] (2) X1: The deflection in the width direction of the sample glass corresponding to the evaluation area for measuring the difference in deflection between the front and back sides when the guaranteed side faces downward. X2: Deflection in the width direction when the guaranteed surface is facing upward for the sample glass corresponding to the evaluation area where the difference in deflection between the front and back surfaces is measured

[0016] In this way, when the glass substrate is oriented with the guaranteed surface facing upward, the central portion in the width direction corresponding to the evaluation areas C, D, and E has a bowl-like or substantially flat shape in the width direction. This further reduces the occurrence of positional deviation of the glass substrate when the non-guaranteed surface of the glass substrate is suctioned by the suction surface plate. In other words, the total pitch deviation of the thin film pattern can be further reduced.

[0017] (f) In the configuration of (e) above, the average value ΔV of the difference in front and back deflection in the width direction of the evaluation areas A, B, C, D, E, F, and G A-G is preferably negative.

[0018] In this way, the glass substrate has a bowl-like shape across its entire width with the guaranteed side facing upward, which further reduces positional deviation of the glass substrate when the non-guaranteed side of the glass substrate is chucked by the chuck surface plate, thereby further reducing the total pitch deviation of the thin film pattern.

[0019] (g) In the configuration of (e) or (f) above, the maximum value ΔV of the difference in front and back deflection in the width direction among the evaluation areas A, B, C, D, E, F, and G max and the minimum value ΔV of the difference in front and back deflection in the width direction among the evaluation areas A, B, C, D, E, F, and G. min Difference ΔV max -ΔV min However, it is preferable that the thickness is 0.7 mm or less.

[0020] This reduces the variation in the difference in the warp between the front and back sides in the width direction. In other words, it is possible to suppress large changes in the shape of the glass substrate in the width direction, and therefore it is possible to more reliably suppress insufficient suction or poor suction when the non-guaranteed side of the glass substrate is suctioned by the suction surface plate. Therefore, it is possible to further reduce the total pitch deviation of the thin film pattern.

[0021] (h) In any of the above configurations (a) to (g), the glass substrate is preferably an alkali-free glass substrate for displays, having a strain point of 670°C or higher, a Young's modulus of 77 GPa or higher, and a thermal shrinkage of 40 ppm or less when held at 500°C for 1 hour.

[0022] (i) In any of the above configurations (a) to (h), it is preferable that the arithmetic mean roughness Ra of the non-guaranteed surface is 0.5 nm or less.

[0023] (j) In any of the above configurations (a) to (i), it is preferable that the length of the second side is 2200 mm or more.

[0024] (k) In the configuration of (j) above, it is more preferable that the length of the first side is 1900 mm or more.

[0025] (l) In any of the above configurations (a) to (k), the thickness of the glass substrate is preferably 0.5 mm or less.

[0026] (m) The present invention, which has been invented to solve the above problems, is a method for manufacturing an electronic device, comprising a preparation step of preparing a glass substrate having the above-mentioned configurations (a) to (l) as appropriate, and a fabrication step of fabricating an electronic device using the glass substrate, wherein the fabrication step includes a suction step of suctioning the glass substrate with its protective surface facing upward while it is placed on a suction table, and the suction step is characterized in that suction of the glass substrate proceeds along the drawing direction, starting from the center of the glass substrate in the drawing direction.

[0027] In this way, for the same reasons as already mentioned, it is possible to manufacture an electronic device equipped with a glass substrate in which the total pitch deviation of the thin film pattern is reliably reduced. [Effects of the Invention]

[0028] According to the present invention, it is possible to provide a glass substrate capable of reliably reducing the total pitch deviation of thin film patterns, and an electronic device including a glass substrate in which the total pitch deviation of thin film patterns is reliably reduced. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a plan view of a glass substrate according to an embodiment of the present invention. [Figure 2] FIG. 1 is a plan view for explaining a method for measuring a difference in deflection between the front and back surfaces of a sample glass cut out from a glass substrate in the sheet drawing direction. [Figure 3] 3 is a side view of a sample glass, the difference between the front and back deflections of which is measured by the method shown in FIG. 2, as viewed from the direction of arrow I. FIG. [Figure 4] FIG. 10 is a plan view for explaining a method for measuring a difference in deflection between the front and back surfaces in the width direction of a glass sample cut out from a glass substrate. [Figure 5] 5 is a side view of a sample glass, the difference between the front and back deflections of which is measured by the method shown in FIG. 4, as viewed from the direction of arrow II. FIG. [Figure 6A] FIG. 10 is a diagram showing a suction step included in a method for manufacturing an electronic component according to an embodiment of the present invention, illustrating a state at the beginning of the suction step. [Figure 6B] FIG. 10 is a diagram showing a suction step included in the method for manufacturing an electronic component according to one embodiment of the present invention, illustrating a state in the middle of the suction step. [Figure 6C] FIG. 10 is a diagram showing a suction step included in the method for manufacturing an electronic component according to one embodiment of the present invention, illustrating a state at the end of the suction step. [Figure 7] 1 is a side cross-sectional view showing a manufacturing apparatus for manufacturing a glass substrate according to an embodiment of the present invention. [Figure 8]1 is a front cross-sectional view showing a manufacturing apparatus for manufacturing a glass substrate according to an embodiment of the present invention. [Figure 9] FIG. 8 is an enlarged view of the annealer roller and its surroundings in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0031] (First embodiment) As shown in FIG. 1 , the glass substrate 1 according to this embodiment is manufactured by a known forming method involving sheet drawing, such as a downdraw method, such as an overflow downdraw method, a slot downdraw method, or a redraw method, or a float method. In this embodiment, a glass ribbon is formed by the overflow downdraw method, and a rectangular glass substrate 1 of a predetermined size is obtained by cutting from this glass ribbon. The overflow downdraw method has the advantage that both the front and back surfaces of the formed glass ribbon are formed without coming into contact with any part of the formed body during the forming process, resulting in fire-polished surfaces with very smooth surface properties. Note that the glass substrate 1 formed by the overflow downdraw method has a forming confluence surface in the central region in the sheet thickness direction.

[0032] The glass substrate 1 has a first side 1y along the drawing direction Y and a second side 1x along the width direction X perpendicular to the drawing direction Y. The drawing direction Y of the glass substrate 1 can be observed as a striped pattern, for example, by irradiating light from a light source (e.g., a xenon light) on the glass substrate 1 in a darkroom while adjusting the angle of the glass substrate 1 and projecting the transmitted light onto a screen. Therefore, the drawing direction Y can be identified during molding even in the state of the glass substrate 1 after molding.

[0033] One main surface of the glass substrate 1 is designated as the guaranteed surface 1a, and the other main surface is designated as the non-guaranteed surface 1b. The guaranteed surface 1a is the surface on which a thin film pattern is formed during the manufacture of an electronic device, and is guaranteed to have a predetermined quality, and is maintained in a non-contact state as much as possible during each process, such as transportation and processing, of the glass substrate 1. In this case, the non-guaranteed surface 1b, located behind the guaranteed surface 1a, is the contact surface that comes into contact with transportation equipment and the like during transportation or each process, such as processing.

[0034] An example of the glass substrate 1 is a low-alkali glass substrate for displays. Here, examples of the "display" include liquid crystal displays and organic EL displays. Furthermore, "low-alkali glass" refers to glass with a low content of alkaline components (alkali metal oxides) or glass that is substantially free of alkaline components.

[0035] A specific composition of the low-alkali glass preferably contains, in mole percent, 60 to 75% of SiO2, 5 to 20% of Al2O3, 0 to 15% of B2O3, 0 to less than 1% of Li2O+Na2O+K2O (total amount of Li2O, Na2O, and K2O), 0 to 10% of MgO, 0 to 15% of CaO, 0 to 10% of SrO, and 0 to 10% of BaO, and among these, the following glass composition examples are particularly preferred.

[0036] An example of the first glass composition preferably contains, in mole percent, 60-70% SiO, 9.5-17% AlO (particularly 11-15%), 0-9% BO (particularly 5-7%), 0-1% or less of LiO + NaO + KO (particularly 0-0.5%), 0-8% MgO (particularly 2-6%), 2-15% CaO (particularly 6-11%), 0-10% SrO (particularly 0.1-3%), and 0.1-5% BaO. This increases the liquidus viscosity and Young's modulus. As a result, it becomes easier to produce a thin glass sheet G, and furthermore, it becomes easier to reduce the amount of deflection of the glass sheet G.

[0037] An example of the second glass composition preferably contains, in mole percent, 62 to 72% SiO, 9.5 to 16% (especially 11 to 15%) AlO, 1 to 8% (especially 2 to 4%) BO, 0 to less than 1% (especially 0 to 0.5%) LiO + NaO + KO, 1 to 9% (especially 4 to 8%) MgO, 2 to 10% (especially 3 to 8%) CaO, 0.1 to 5% (especially 1 to 3%) SrO, and 0.1 to 5% (especially 1 to 3%) BaO. This increases the liquidus viscosity and Young's modulus. As a result, it becomes easier to produce a thin glass sheet G, and furthermore, it becomes easier to reduce the amount of deflection of the glass sheet G.

[0038] An example of the third glass composition preferably contains, in mole percent, 67-77% SiO2, 9-14% Al2O3, 0-3% (especially 0-1%) B2O3, 0-1% or less (especially 0-0.5%) Li2O+Na2O+K2O, 0-5% (especially 2-5%) MgO, 0-10% (especially 6-9%) CaO, 0-5% SrO, and 0-7% (especially 3-6%) BaO. This facilitates raising the strain point to 730°C or higher.

[0039] The maximum deflection amount Ymax (mm) when the glass substrate 1 is supported at two points can be defined by the following formula (3). Y max = 5g / 32×d(1-ν 2 ) / E×10 -9 ×L 4 / t 2 (3) where g is the gravitational acceleration [m / S 2 ], d: density of glass substrate [g / cm 3 ], E: Young's modulus [GPa], ν: Poisson's ratio, L: distance between support points [mm], t: thickness of glass substrate [mm].

[0040] As shown in formula (3), the amount of bending of the glass substrate 1 is inversely proportional to the square of the thickness, and therefore the thinner the glass substrate 1, the more pronounced the effect of bending. In particular, thin glass substrates 1 of 0.5 mm or less are prone to bending. Therefore, in the case of thin glass substrates 1, bending of the glass substrate 1 significantly affects the shape of the glass substrate 1 during the film formation process.

[0041] As shown in formula (3), the amount of deflection of the glass substrate 1 is proportional to the fourth power of the distance between the support points when holding the glass substrate 1. Therefore, even in the case of a large glass substrate 1, the deflection of the glass substrate 1 significantly affects the shape of the glass substrate 1 during the film formation process.

[0042] In equation (3), the Poisson's ratio for glass substrates for displays is approximately 0.2, so there is no difference, and the property that has the greatest effect on deflection is Young's modulus. Glass materials with a high Young's modulus can suppress deflection and deformation of the glass substrate 1 during display processes such as heat treatment and transportation. This makes them suitable for use as glass substrates for high-resolution displays.

[0043] The length of the first side 1y of the glass substrate 1 is preferably 1300 mm or more, 1500 mm or more, 1800 mm or more, 1900 mm or more, particularly 2100 mm or more. The length of the second side 1x of the glass substrate 1 is preferably 1500 mm or more, 1800 mm or more, 2150 mm or more, 2200 mm or more, particularly 2400 mm or more. On the other hand, the lengths of both the first side 1y and the second side 1x are preferably 4000 mm or less. In this embodiment, the length of the first side 1y is 2200 mm or 1950 mm, and the length of the second side 1x is 2500 mm or 2250 mm.

[0044] The thickness of the glass substrate 1 is preferably 1.3 mm or less, 1.0 mm or less, 0.7 mm or less, particularly preferably 0.5 mm or less, while the thickness of the glass substrate 1 is preferably 0.2 mm or more, particularly preferably 0.3 mm or more.

[0045] The Young's modulus of the glass substrate 1 is preferably 77 GPa or more, 80 GPa or more, and particularly preferably 83 GPa or more. The "Young's modulus" refers to a value measured based on the dynamic elastic modulus measurement method (resonance method) in accordance with JIS R1602.

[0046] Furthermore, if a heat treatment step of heating at high temperature is performed after film formation on the glass substrate 1, the heat treatment will cause shrinkage (compaction) of the glass substrate 1. Therefore, when the glass substrate 1 is used in the manufacturing process of a high-definition display device, for example, it is preferable that the glass substrate 1 has characteristics that result in a small amount of shrinkage.

[0047] The strain point of the glass substrate 1 is preferably 670°C or higher, 700°C or higher, and particularly 720°C or higher. This makes it easier to suppress thermal shrinkage and deformation of the glass substrate 1, for example, during the manufacturing process of high-definition display devices, particularly oxide TFTs or low-temperature polysilicon TFTs. On the other hand, if the strain point of the glass substrate 1 is too high, the temperature during the molding process, particularly the annealing process, becomes too high, making it difficult to control the shape of the glass substrate 1 and increasing manufacturing costs. Therefore, the strain point of the glass substrate 1 is preferably 800°C or lower, 790°C or lower, and particularly 780°C or lower. The "strain point" is a value measured according to the methods of ASTM C336 and C338.

[0048] The amount of thermal shrinkage of the glass plate 1 when held at 500°C for 1 hour is preferably 40 ppm or less, 30 ppm or less, and particularly 20 ppm or less. This suppresses shrinkage (compaction) of the glass substrate 1 due to heat treatment, even when a heat treatment step involving heating at high temperatures is performed after film formation on the glass substrate 1. Therefore, the glass substrate 1 is suitable for use as a glass substrate for high-resolution displays. The "amount of thermal shrinkage" is measured as follows: First, a 160 mm x 30 mm rectangular sample is prepared as a measurement sample. A mark is made on this rectangular sample approximately 20 to 40 mm from the long edge using #1000 waterproof abrasive paper, and the sample is folded and split perpendicular to the marking to obtain two test pieces. One of the split test pieces is heat-treated under specified conditions, and then the heat-treated sample and the unheated sample are aligned and fixed together with tape or the like. In this state, the amount of positional deviation (ΔL1, ΔL2) of the markings is read using a laser microscope, and the amount of thermal shrinkage is calculated according to (4) below. Heat shrinkage amount [ppm]=(ΔL1[μm]+ΔL2[μm]) / 160×10 -3 (4)

[0049] The shape of the glass substrate 1, specifically the shape along the drawing direction Y of the glass substrate 1 and the shape along the width direction X can be evaluated using the difference in deflection between the front and back surfaces.

[0050] First, a method for evaluating the shape of the glass substrate 1 along the drawing direction Y based on the difference Y1-Y2 between the front and back deflections will be described.

[0051] As shown in FIG. 1, seven rectangular evaluation areas A to G are set on one glass substrate 1 at different positions along the width direction X. The evaluation areas A to G are set in order from one end of the width direction X. The evaluation areas B to F are arranged in a line along the width direction X without any gaps. The evaluation areas A and G are positioned in different positions in the drawing direction Y from the evaluation areas B to F. The center of evaluation area A overlaps with evaluation area B in the width direction, and the center of evaluation area G overlaps with evaluation area F in the width direction. In this case, the evaluation areas A to G are set within an effective zone (not shown) on the guaranteed surface of the glass substrate 1 where a thin film pattern is formed in a film formation process, for example. In this embodiment, the dimension of the effective zone along the width direction X is 2500 mm.

[0052] In this embodiment, each evaluation area A to G is rectangular, with a side 2y length along the drawing direction Y of 500 mm and a side 2x length along the width direction X of 400 mm. The overlapping length between evaluation area A and evaluation area B and the overlapping length between evaluation area G and evaluation area F are 150 mm. If the dimension of the effective zone along the width direction X is not 2500 mm, the length of side 2x along the width direction X is set to 16% of the dimension of the effective zone along the width direction X. Furthermore, the overlapping length between evaluation area A and evaluation area B and the overlapping length between evaluation area G and evaluation area F are set to 6% of the dimension of the effective zone along the width direction X. The length of side 2y along the drawing direction Y is 125% of the length of side 2x along the width direction X.

[0053] Glass samples (glass pieces) 3 of positions and sizes corresponding to the evaluation regions A to G are taken from the glass substrate 1, and seven glass samples 3 corresponding to the evaluation regions A to G are obtained per glass substrate 1. That is, the glass samples 3 have a side 3y along the drawing direction Y, which corresponds to the side 2y of the evaluation regions A to G, and a side 3x along the width direction X, which corresponds to the side 2x of the evaluation regions A to G.

[0054] After preparing seven glass samples 3 in this manner, the difference Y1-Y2 between the front and back deflections of each glass sample 3 in the drawing direction Y is measured. Specifically, as shown in FIG. 2, the non-protected surface 3b of the glass sample 3 (the surface on the same side as the non-protected surface 1b of the glass substrate 1) is facing upward, and both ends of the glass sample 3 in the drawing direction Y are supported by a pair of support members 4. In this case, the support span M of the glass sample 3 by the pair of support members 4 is set to 480 mm when the length of the side 3y along the drawing direction Y is 500 mm and the length of the side 3x along the width direction X is 400 mm. In other cases, it is set to a value obtained by subtracting 20 mm from the length of the side 3y of the glass sample 3 parallel to the drawing direction Y. In this state, the magnitude of the first deflection Y1 of the glass sample 3 in the drawing direction Y (shown by the solid line in the figure) is measured, as shown in FIG. 3. The measured magnitude of the first deflection Y1 is converted to the first deflection Y1 when the support span M is 350 mm. For example, if the support span M is M1 (any value) mm, convert it as Y1 x (350 / M1).

[0055] Similarly, the glass sample 3 is turned upside down so that the guaranteed surface 3a of the glass sample 3 (the surface on the same side as the guaranteed surface 1a of the glass substrate 1) faces upward, and both ends of the glass sample 3 in the drawing direction Y are supported by a pair of support members 4. In this state, as shown in Fig. 3, the magnitude of the second deflection Y2 of the glass sample 3 in the drawing direction Y (the state indicated by the dashed line in the figure) is measured. The measured magnitude of the second deflection Y2 is converted to the second deflection Y2 when the support span M is 350 mm.

[0056] After measuring the first deflection Y1 and the second deflection Y2 in this manner, the difference Y1-Y2 between the front and back deflections in the drawing direction Y is obtained by subtracting the second deflection Y2 from the first deflection Y1.

[0057] By performing the above procedure on all the glass specimens 3 corresponding to the evaluation regions A to G, the shape in the drawing direction Y for each evaluation region A to G can be determined. For example, as shown in Figure 3, when the first deflection Y1 is smaller than the second deflection Y2 and the front-to-back deflection difference Y1-Y2 is negative, the deflection direction of the glass specimen 3 in the glass substrate 1 in the drawing direction Y is such that the guaranteed surface 3a is concave, and the magnitude of the deflection can be evaluated by the absolute value of the front-to-back deflection difference Y1-Y2. On the other hand, when the first deflection Y1 is larger than the second deflection Y2 and the front-to-back deflection difference Y1-Y2 is positive (not shown), the deflection direction of the glass specimen 3 in the glass substrate 1 in the drawing direction Y is such that the non-guaranteed surface 3b is concave, and the magnitude of the deflection can be evaluated by the absolute value of the front-to-back deflection difference Y1-Y2. When any linear region (cross section) along the drawing direction Y of the glass substrate 1 is viewed, the annealing conditions at each point on that linear region are substantially the same regardless of the position in the drawing direction Y. Therefore, if the position in the width direction X is the same, the shape in the drawing direction Y will show substantially the same tendency. Therefore, simply by determining the difference Y1-Y2 between the front and back deflections of the sample glass 3 corresponding to each of the evaluation regions A to G, the shape in the drawing direction Y of the entire effective zone of the glass substrate 1 can be indirectly grasped.

[0058] Next, a method for evaluating the shape of the glass substrate 1 in the width direction X based on the difference X1-X2 between the front and back deflections will be described.

[0059] Seven glass samples 3 corresponding to evaluation areas A to G shown in FIG. 1 are prepared, and the difference in front-to-back deflection X1-X2 in the width direction X of each glass sample 3 is measured. The prepared glass samples 3 may be the same as those used to evaluate the shape along the drawing direction Y. Specifically, as shown in FIG. 4, the non-supported surface 3b of the glass sample 3 is placed upward, and both ends of the glass sample 3 in the width direction X are supported by a pair of support members 5. In this case, the support span N of the glass sample 3 by the pair of support members 5 is set to 380 mm when the length of the side 3y along the drawing direction Y is 500 mm and the length of the side 3x along the width direction X is 400 mm. In other cases, the support span N is set to a value obtained by subtracting 20 mm from the length of the side 3x of the glass sample 3 parallel to the width direction X. In this state, the magnitude of the first deflection X1 (indicated by the solid line in the figure) of the glass sample 3 in the width direction X is measured, as shown in FIG. 5. The magnitude of the measured first deflection X1 is converted into the first deflection X1 when the support span N is 350 mm.

[0060] Similarly, the glass sample 3 is turned upside down so that the protective surface 3a of the glass sample 3 faces upward, and both ends of the glass sample 3 in the width direction X are supported by a pair of support members 5. In this state, as shown in Fig. 5, the magnitude of the second deflection X2 (indicated by the dashed line in the figure) in the width direction X of the glass sample 3 is measured. The measured magnitude of the second deflection X2 is converted to the second deflection X2 when the support span N is 350 mm.

[0061] After measuring the first deflection X1 and the second deflection X2 in this manner, the difference in front and back deflection X1-X2 in the width direction X is obtained by subtracting the second deflection X2 from the first deflection X1.

[0062] By performing the above procedure on all glass specimens 3 corresponding to each evaluation region A to G, the shape in the width direction X of each evaluation region A to G can be determined. For example, as shown in FIG. 5, when the first deflection X1 is smaller than the second deflection X2 and the difference between the front and back deflections X1-X2 is negative, the deflection direction of the glass specimen 3 in the width direction X of the glass substrate 1 is such that the guaranteed surface 3a is concave, and the magnitude of the deflection can be evaluated by the absolute value of the difference between the front and back deflections X1-X2. On the other hand, when the first deflection X1 is larger than the second deflection X2 and the difference between the front and back deflections X1-X2 is positive (not shown), the deflection direction of the glass specimen 3 in the width direction X of the glass substrate 1 is such that the non-guaranteed surface 3b is concave, and the magnitude of the deflection can be evaluated by the absolute value of the difference between the front and back deflections X1-X2. Here, when viewing any linear region (cross section) of the glass substrate 1 along the width direction X, the annealing conditions at each point on the linear region are substantially different depending on the position in the width direction X. However, since each of the evaluation areas A to G extends across the entire width direction X of the effective zone of the glass substrate 1, by calculating the difference X1-X2 in the front-to-back deflection of the sample glass 3 corresponding to each of the evaluation areas A to G, the shape of the entire effective zone of the glass substrate 1 in the width direction X can be directly grasped.

[0063] When the shape of the glass substrate 1 according to this embodiment is evaluated based on the difference in the front and back warpages, it has the following shape quality.

[0064] That is, the glass substrate 1 is a glass sample 3 corresponding to the evaluation areas C, D, and E located at the center of the width direction X, and the average value ΔH of the difference in front and back deflections Y1-Y2 in the drawing direction Y of the glass sample 3 is C-Ebecomes negative. As a result, with the guaranteed surface 1a facing upward, the center portion in the width direction X of the glass substrate 1 has a bowl-like shape (concave shape) in the drawing direction Y over substantially the entire length in the drawing direction Y. With such a bowl-shaped glass substrate 1, when the guaranteed surface 1a faces upward and the non-guaranteed surface 1b on the back side of the guaranteed surface 1a is suctioned by a suction surface plate S, the suction proceeds smoothly along the drawing direction Y, starting from the center portion 1c in the drawing direction Y, as shown in FIGS. 6(a) to 6(c), for example. This makes it possible to suppress positional deviation of the glass substrate 1 on the suction surface plate S. In other words, it becomes possible to reliably reduce the total pitch deviation of the thin film pattern formed on the guaranteed surface 1a of the glass substrate 1.

[0065] The glass substrate 1 is measured by calculating the average value ΔH of the difference in front and back deflections Y1-Y2 in the drawing direction Y of the sample glass 3 corresponding to all evaluation areas A to G. A-G is preferably negative. This causes the entire width direction X of the effective zone of the glass substrate 1 to have a bowl shape over substantially the entire length in the sheet drawing direction Y. This further reduces the occurrence of positional deviation of the glass substrate 1. Note that it is not necessary for all values ​​of the front-to-back deflection differences Y1-Y2 in the evaluation regions A to G to be negative, and some of the values ​​may be positive.

[0066] The glass substrate 1 is measured by calculating the difference in the front and back deflections in the drawing direction Y in the evaluation areas A to G as ΔH A ,ΔH B ,ΔH C ,ΔH D ,ΔH E ,ΔH F ,ΔH G When this is the case, ΔH A ~ΔH G At least ΔH C ,ΔH D ,ΔH E are preferably negative. In particular, ΔH C ,ΔH D ,ΔH E It is preferable that at least two-thirds of the region including the region A and B are all negative. This reduces the change in shape within the plane of the glass substrate 1, resulting in a bowl-like shape that changes smoothly.

[0067] The glass substrate 1 is a glass sample 3 corresponding to all evaluation areas A to G. The glass sample 3 ... max and the minimum value ΔH of the difference Y1-Y2 between the front and back deflections in the drawing direction Y of the sample glass 3 corresponding to all the evaluation areas A to G. min Difference ΔH max -ΔH min is preferably 0.5 mm or less, and more preferably 0.3 mm or less. This reduces the variation in the difference Y1-Y2 between the front and back deflections in the drawing direction Y. In other words, since it is possible to suppress large changes in the shape of the glass substrate 1 in the drawing direction Y, it is possible to suppress insufficient suction or poor suction when the non-guaranteed surface 1b of the glass substrate 1 is suctioned by the suction surface plate S.

[0068] The glass substrate 1 is measured in the width direction X of the sample glass 3 corresponding to the evaluation areas C, D, and E located in the center of the width direction X, and the average value ΔV C-E But, ΔV C-E ≦0. As a result, when the glass substrate 1 is placed with the guaranteed surface 1a facing upward, the central portion in the width direction X also has a bowl-like shape or is substantially flat in the width direction X. Therefore, it is possible to more reliably suppress the occurrence of positional deviation of the glass substrate 1 on the suction surface plate S. ΔV C-E <0, the adsorption from the center to the periphery of the glass substrate 1 proceeds without delay, and the shape of the glass substrate in the adsorbed state becomes flat and stable. C-E <0 is preferred.

[0069] The glass substrate 1 is measured by the average value ΔV of the difference in front and back deflection X1-X2 in the width direction X of the sample glass 3 corresponding to all evaluation areas A to G. A-G is preferably negative. This causes the entire width direction X of the effective zone of the glass substrate 1 to have a bowl shape in the width direction X as well. Therefore, it is possible to more reliably suppress the occurrence of positional deviation of the glass substrate 1 on the suction surface plate S. Note that it is not necessary for all values ​​of the front-back deflection differences X1-X2 in the evaluation areas A to G to be negative, and some of the values ​​may be positive.

[0070] The glass substrate 1 is the maximum value ΔV of the difference in front and back deflection X1-X2 in the width direction X of the sample glass 3 corresponding to all evaluation areas A to G. max and the minimum value ΔV of the difference X1-X2 between the front and back deflections in the width direction X of the glass sample 3 corresponding to all evaluation areas A to G. min Difference ΔV max -ΔV min is preferably 0.7 mm or less, more preferably 0.4 mm or less, and most preferably 0.3 mm or less. This reduces the variation in the difference in front-to-back deflection X1-X2 in the width direction X. In other words, since it is possible to suppress large changes in the shape of the glass substrate 1 in the width direction X, it is possible to suppress insufficient suction or poor suction when the non-support surface 1b of the glass substrate 1 is suctioned by the suction surface plate S.

[0071] Here, the glass substrate 1 may be irregularly misaligned, resulting in a total pitch deviation, due to the extremely small roughness of the non-guaranteed surface 1b of the glass substrate 1 (calculated average roughness Ra, for example, 0.5 nm or less). This is particularly true when the glass substrate 1 is formed using the overflow downdraw method. The small roughness of the non-guaranteed surface 1b of the glass substrate 1 tends to be small. If the non-guaranteed surface 1b of the glass substrate 1 has low roughness, static electricity may be generated on the surface plate during film formation, impairing the sliding of the glass substrate 1 and hindering its adherence to the surface plate. In particular, for glass substrates 1 with an upwardly convex shape, in which the difference in the curvature between the front and back surfaces of the glass substrate 1 is positive at the center and / or negative at the periphery, the curvature of the periphery becomes relatively large, suppressing glass spreading at the periphery on the surface plate. As a result, the glass substrate 1 may not be stably moved to the desired position, resulting in adsorption, creating a gap between the glass substrate 1 and the surface plate, potentially causing a misalignment (total pitch deviation). However, in the present invention, as described above, the shape (warping) of the glass substrate 1 is controlled, so that the total pitch deviation can be suppressed even when the roughness of the non-guaranteed surface 1b is small (calculated average roughness Ra is 0.5 nm or less). Note that the "arithmetic average roughness Ra" is the arithmetic average roughness in accordance with JIS R 1683:2014, and is measured using an atomic force microscope.

[0072] Next, a method for manufacturing an electronic device using the glass substrate 1 having the above configuration will be described. Here, the electronic device is, for example, a panel display such as a liquid crystal display, and is used as a component of a mobile phone (especially a smartphone), a tablet computer, a digital camera, a touch panel display, a large television, etc.

[0073] A method for manufacturing this type of electronic device includes a preparation step of preparing the glass substrate 1 described above, and a fabrication step of fabricating an electronic device using the glass substrate 1.

[0074] Although not shown in the drawings, the manufacturing process includes a film-forming step of forming a thin film pattern on the protection surface 1a of the glass substrate 1 by photolithography.

[0075] For example, when manufacturing a thin film transistor (TFT), the film formation process includes, in this order, a metal film formation process in which a metal film (e.g., copper, aluminum, etc.) that will be the basis for the thin film pattern (transistor wiring) is formed on the protective surface 1a of the glass substrate 1; a resist film formation process in which a resist film is formed on the metal film; an exposure process in which the resist film is irradiated with light such as ultraviolet light to transfer the pattern of the photomask; a development process in which the exposed portion (positive type) or unexposed portion (negative type) of the resist layer is removed; an etching process in which the metal film in the portion not covered by the resist film is removed; and a resist film removal process in which the resist film is removed.

[0076] For example, when manufacturing a color filter, the process includes a resist film formation step, an R filter film formation step, a G filter film formation step, and a B filter film formation step. Each of these film formation steps includes a film formation step, an exposure step, and a development step.

[0077] Of these, the exposure process includes, as a pre-process of irradiating light through a photomask, a suction process in which the glass substrate 1 is placed on a suction surface plate S with the guaranteed surface 1a facing upward, and the non-guaranteed surface 1b of the glass substrate 1 is suctioned by the suction surface plate S, as shown in Figures 6A to 6C. The suction surface plate S is configured so that the suction range gradually expands from the center in the sheet pulling direction Y toward the ends in the sheet pulling direction Y. Note that films such as metal films are not shown in Figures 6A to 6C.

[0078] In the suction process, the glass substrate 1 placed on the suction surface plate S has at least a central portion 1c in the width direction X that is bowl-shaped in the drawing direction Y with the guaranteed surface 1a facing upward. Therefore, in the suction process, the suction of the glass substrate 1 can proceed along the drawing direction Y, starting from the central portion 1c of the glass substrate 1. Specifically, as shown in FIG. 6A, the central portion 1c of the glass substrate 1 is first suctioned to the suction surface plate S. Then, as shown in FIG. 6B, suction proceeds sequentially from the central portion 1c toward the second edge 1x (i.e., the end in the drawing direction Y), as indicated by the arrow W. Then, as shown in FIG. 6C, this suction progresses so that the entire glass substrate 1 is properly suctioned to the suction surface plate S without significant positional deviation. Therefore, in the exposure process, the photomask pattern can be properly transferred to the resist film, thereby reliably reducing the total pitch deviation of the thin film pattern formed on the guaranteed surface 1a of the glass substrate 1.

[0079] Next, a method for manufacturing the glass substrate 1 having the above configuration will be described.

[0080] 7 and 8, the manufacturing apparatus 11 for the glass substrate 1 includes a forming furnace 12, an annealing furnace 14 located below the forming furnace 12, a cooling chamber 15 located below the annealing furnace 14, and a cutting chamber 16 located below the cooling chamber 15. The forming furnace 12 and the annealing furnace 14, the annealing furnace 14 and the cooling chamber 15, and the cooling chamber 15 and the cutting chamber 16 are separated by partition members (e.g., floors of a building) F1, F2, and F3, respectively, each having an opening (e.g., a slit) through which the glass ribbon Gr passes.

[0081] The forming furnace 12 is a region for forming a glass ribbon Gr from the molten glass Gm by the overflow downdraw method. Inside the forming furnace 12, there are arranged a forming body 13 for forming the glass ribbon Gr from the molten glass Gm, and edge rollers 17 for cooling both ends in the width direction X of the glass ribbon Gr formed by the forming body 13.

[0082] A groove (overflow groove) 18 is formed in the width direction at the top of the formed body 13. A supply pipe 19 is connected to one end of the groove 18. Molten glass Gm is supplied into the groove 18 through this supply pipe 19. The method of supplying the molten glass Gm is not limited to this. For example, the molten glass Gm may be supplied from both ends of the groove 18, or the molten glass Gm may be supplied from above the groove 18.

[0083] Each of the outer surfaces 20 of the molded body 13 includes a vertical surface portion 21 that is flat along the vertical direction, and an inclined surface portion 22 that is connected to the lower side of the vertical surface portion 21 and is flat and inclined with respect to the vertical direction. The vertical surface portions 21 are parallel to each other. The inclined surface portions 22 are inclined so that they approach each other as they extend downward. In other words, due to the formation of the inclined surface portions 22, the molded body 13 has a wedge shape that tapers downward when viewed from the side, and the corner where the inclined surface portions 22 intersect forms the lower end portion 13a of the molded body 13. The vertical surface portions 21 may be modified to have an inclined surface or a curved surface, or may be omitted.

[0084] The edge rollers 17 are configured as a pair of rollers that sandwich each end of the glass ribbon Gr in the width direction directly below the forming body 13. The edge rollers 17 are cantilever type rollers that are constantly internally cooled during the forming process. For this reason, the edge rollers 17 are sometimes referred to as cooling rollers.

[0085] The annealing furnace 14 is a region for reducing warpage and internal strain of the glass ribbon Gr. Annealer rollers 23 are arranged inside the annealing furnace 14. The annealer rollers 23 are configured as a pair of rollers that hold each end of the glass ribbon Gr in the width direction. The annealer rollers 23 may be double-supported rollers arranged to span the entire width direction of the glass ribbon Gr, but in this embodiment, they are cantilevered rollers. The annealer rollers 23 are provided in multiple stages in the vertical direction.

[0086] The cooling chamber 15 is a region for cooling the glass ribbon Gr to near room temperature. Conveying rollers 24 are arranged inside the cooling chamber 15. The conveying rollers 24 are configured as a pair of rollers that hold each end of the glass ribbon Gr in the width direction. The conveying rollers 24 may be double-supported rollers arranged to span the entire width direction of the glass ribbon Gr, but in this embodiment, they are cantilevered rollers. The conveying rollers 24 are provided in multiple stages in the vertical direction.

[0087] The annealer rollers 23 and / or the conveying rollers 24 may include rollers that do not sandwich both end portions of the glass ribbon Gr in the width direction X. In other words, the opposing distance between the roller pairs constituting the annealer rollers 23 and / or the conveying rollers 24 may be set larger than the thickness of the glass ribbon Gr at both end portions in the width direction X, so that the glass ribbon Gr passes between the roller pairs. Note that in the present embodiment, both end portions in the width direction X of the glass ribbon Gr obtained by the manufacturing apparatus 11 include ear portions that are thicker than the central portion in the width direction X due to the influence of shrinkage during the forming process, etc.

[0088] The cutting chamber 16 is an area for cutting the glass ribbon Gr to a predetermined size to obtain a glass substrate 1 as a glass article. A cutting device (not shown) for cutting the glass ribbon Gr is disposed inside the cutting chamber 16. In this embodiment, the method for cutting the glass ribbon Gr by the cutting device is scribe cutting, in which a scribe line is formed on the glass ribbon Gr and then the glass ribbon Gr is bent and broken along the scribe line, but is not limited to this. The cutting method by the cutting device may also be, for example, laser cleaving or laser fusing.

[0089] In the method for manufacturing a glass substrate 1 using the manufacturing apparatus 11, first, in the forming furnace 12, molten glass Gm is supplied to the grooves 18 of the forming body 13. The molten glass Gm spilling out of the grooves 18 on both sides flows down along the vertical surfaces 21 and the inclined surfaces 22 and meets again at the lower end 13a. Thus, a strip-shaped glass ribbon Gr is continuously formed from the molten glass Gm (forming process). Next, in the annealing furnace 14, the glass ribbon Gr is annealed (annealing process), and in the cooling chamber 15, the glass ribbon Gr is cooled to approximately room temperature (cooling process). Thereafter, in the cutting chamber 16, the glass ribbon Gr is cut to obtain glass substrates 1 (cutting process). The cutting process includes a first cutting process in which the glass ribbon Gr is cut in the width direction X at predetermined lengths to obtain glass substrates 1, and a second cutting process in which edge portions at both ends of the glass substrate 1 in the width direction X are cut and removed. The drawing direction Y of the glass substrate 1 manufactured in this manner corresponds to the vertical direction of the glass ribbon Gr in FIGS. 7 and 8 . In the present manufacturing method, the processes subsequent to the molding process are not particularly limited. For example, the present manufacturing method may further include a precision cutting process for cutting the glass substrate 1 to a desired size, an edge processing process, a cleaning process, an inspection process, a packaging process, etc.

[0090] Here, for example, by appropriately annealing the glass ribbon Gr in the annealing step carried out in the annealing furnace 14, the above-mentioned shape quality can be obtained in the glass substrate 1 cut out from the glass ribbon Gr. In detail, for example, as shown in Fig. 9 , in the annealing furnace 14, the position of the glass ribbon Gr in the thickness direction is shifted between an upper annealer roller 23a and a lower annealer roller 23b, thereby producing a glass substrate 1 having the above-mentioned shape quality. When the distance between the upper annealer roller 23a and the lower annealer roller 23b in the vertical direction is P and the distance between the upper annealer roller 23a and the lower annealer roller 23b in the thickness direction is Q, it is sufficient that Q / P is 0.022 or more, preferably 0.03 or more, and more preferably 0.04 or more.

[0091] The annealer rollers 23a, 23b in the plurality of stages satisfying the above positional relationship are preferably provided in a region where the temperature of the glass ribbon Gr is in the range of the strain point to the softening point. Alternatively, the annealer rollers 23a, 23b in the plurality of stages satisfying the above positional relationship are preferably provided in a region where the viscosity of the glass ribbon Gr is in the range of 10 14.5 ~10 7.6 It is preferable that the resistance be set in the region of dPa·s.

[0092] In this way, in the annealing furnace 14, by shifting the position of the glass ribbon Gr in the thickness direction between the upper annealer roller 23a and the lower annealer roller 23b, the glass ribbon Gr becomes bowl-shaped in the sheet drawing direction Y and the width direction X. The shape of the glass ribbon Gr in the width direction X can also be adjusted by changing the tension in the width direction acting on the glass ribbon Gr by the annealer roller 23a. For example, if the tension in the width direction acting on the glass ribbon Gr is increased, the shape of the glass ribbon Gr in the width direction X approaches a flat shape, and if the tension is decreased, the shape of the glass ribbon Gr curves into a bowl shape. The tension in the width direction acting on the glass ribbon Gr can be adjusted, for example, by the temperature of the glass ribbon Gr.

[0093] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0094] For example, the glass substrate 1 has an average value ΔH C-E If is negative, the average value ΔV C-E may be positive. [Example]

[0095] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0096] The present inventors conducted a comparative test to confirm the effects of the present invention as a first example. In this test, glass substrates according to Examples 1 to 10 and glass substrates according to Comparative Examples 1 to 8 were prepared, and the difference in front-to-back deflection Y1-Y2 in the drawing direction Y and the difference in front-to-back deflection X1-X2 in the width direction X were evaluated for each example. In addition, in each example, ΔH calculated from the difference in front-to-back deflection Y1-Y2 and the difference in front-to-back deflection X1-X2 was evaluated. C-E , ΔH A-G , ΔH max -ΔH min , ΔV C-E , ΔV A-G , ΔV max -ΔV min Furthermore, the total pitch deviation and the color variation of the color filter were evaluated.

[0097] For the low-alkali glass substrate for displays according to the embodiment of the present invention, OA-11 material manufactured by Nippon Electric Glass Co., Ltd. was used, which has a strain point of 685°C, a Young's modulus of 78 GPa, and a compaction (amount of thermal shrinkage) of about 25 ppm after heat treatment at 500°C for 1 hour. Evaluations were carried out using several examples below.

[0098] The evaluation conditions for each example in the first embodiment are as follows: (1) The glass substrate in each example has a side length in the drawing direction Y of 2200 mm, a side length in the width direction X of 2500 mm, and a thickness of 0.5 mm. (2) In each example, seven evaluation regions A to G on the glass substrate were set in the manner shown in Fig. 1. Each evaluation region A to G had a side length of 500 mm in the sheet drawing direction Y and a side length of 400 mm in the width direction X. The distances L1 and L2 between the widthwise centers of adjacent evaluation regions in the width direction X were 400 mm between evaluation regions B to F, and 250 mm between evaluation regions A and B and between evaluation regions F and G. (3) When measuring the front-to-back deflection difference Y1-Y2, the support span M in the sheet drawing direction Y of the sample glass corresponding to each of the evaluation regions A to G in each example was set to 480 mm. When measuring the front-to-back deflection difference X1-X2, the support span N in the width direction X of the sample glass corresponding to each of the evaluation regions A to G in each example was set to 380 mm. Note that, in each evaluation region in each example, the same sample glass was used for measuring the front-to-back deflection difference Y1-Y2 and the front-to-back deflection difference X1-X2. (4) A thin film pattern of a color filter consisting of a black matrix was formed on the glass substrate in each example, and the total pitch was measured and the color variation was evaluated. The measured total pitch was evaluated on a four-point scale: excellent (◎), good (〇), fair (△), and poor (×). The color variation was evaluated on a three-point scale: good (〇), fair (△), and poor (×).

[0099] The results of the comparative tests conducted under the above conditions are shown in Tables 1 to 4. Table 1 shows the results of the difference in front and back deflection Y1-Y2 in the drawing direction Y for Examples 1 to 8, and Table 2 shows the results of the difference in front and back deflection X1-X2 in the width direction X for Examples 1 to 8. Meanwhile, Table 3 shows the results of the difference in front and back deflection Y1-Y2 in the drawing direction Y for Comparative Examples 1 to 8, and Table 4 shows the results of the difference in front and back deflection X1-X2 in the width direction X for Comparative Examples 1 to 8.

[0100] [Table 1]

[0101] [Table 2]

[0102] [Table 3]

[0103] [Table 4]

[0104] As can be seen from Tables 1 and 2, in Examples 1 to 10, the average value ΔH of the front and back deflection difference Y1-Y2 in the drawing direction Y in the evaluation areas C to E C-E was a negative value, and the evaluation of the total pitch deviation of the color filter and the evaluation of the color variation were all excellent, good, or fair. In contrast, as can be seen from Tables 3 and 4, in Comparative Examples 1 to 8, the average value ΔH of the front and back deflection difference Y1-Y2 in the sheet drawing direction Y in the evaluation areas C to E C-E was a positive value, and it was impossible to evaluate the total pitch deviation and the color variation. From the above, it can be seen that the average value ΔH of the front and back deflection difference Y1-Y2 in the sheet drawing direction at least in the evaluation areas C to E C-E It can be confirmed that a negative value is effective in reducing the total pitch deviation of the thin film pattern.

[0105] In Examples 1 to 6, ΔH max -ΔH min and ΔV max -ΔV min In contrast, in Examples 7 to 10, ΔH max -ΔH min and ΔV max -ΔV min Either one or both of these increased to values ​​exceeding 0.3 mm, and the evaluation of the total pitch deviation decreased to good. max -ΔH min and ΔV max -ΔV min It can be confirmed that the total pitch deviation can be further reduced by reducing

[0106] In Examples 1, 3, 5 and 6, ΔH A-G and ΔV A-G In Example 4, ΔH A-G was a positive value, and the center in the drawing direction Y was bowl-shaped, but both ends in the drawing direction Y were not bowl-shaped.A-G was a positive value, and the center in the width direction X was bowl-shaped, but both ends in the width direction X were not bowl-shaped. As a result, in Examples 2 and 4, the evaluation of color variation was poor, being fair. From these results, it can be seen that ΔH A-G and ΔV A-G It can be confirmed that the total pitch deviation can be further reduced by setting both of these to negative values.

[0107] Next, a second embodiment will be described. The evaluation conditions for each example in the second embodiment are as follows: (1) The glass substrate in each example has a side length in the drawing direction Y of 1950 mm, a side length in the width direction X of 2250 mm, and a thickness of 0.4 mm. (2) In each example, the seven evaluation regions A to G on the glass substrate were set in the same manner as in Fig. 1. Each of the evaluation regions A to G had a side length of 500 mm in the drawing direction Y and a side length of 400 mm in the width direction X. The distances L1 and L2 between the widthwise centers of adjacent evaluation regions in the width direction X were 400 mm between evaluation regions B to F, and 125 mm between evaluation regions A and B and between evaluation regions F and G. (3) When measuring the front-to-back deflection difference Y1-Y2, the support span M in the sheet drawing direction Y of the sample glass corresponding to each of the evaluation areas A to F in each example was set to 480 mm. When measuring the front-to-back deflection difference X1-X2, the support span N in the width direction X of the sample glass corresponding to each of the evaluation areas A to G in each example was set to 380 mm. Note that, in each evaluation area in each example, the same sample glass was used for measuring the front-to-back deflection difference Y1-Y2 and the front-to-back deflection difference X1-X2. (4) A thin film pattern of a color filter consisting of a black matrix was formed on the glass substrate in each example, and the total pitch was measured and the color variation was evaluated. The measured total pitch was evaluated on a four-point scale: excellent (◎), good (〇), fair (△), and poor (×). The color variation was evaluated on a three-point scale: good (○), fair (△), and poor (×).

[0108] The results of the comparative tests conducted under the above conditions are shown in Tables 5 and 6. Table 5 shows the results of the difference in front and back deflection Y1-Y2 in the drawing direction Y for Examples 11 to 14 and Comparative Examples 9 and 10, and Table 6 shows the results of the difference in front and back deflection X1-X2 in the width direction X for Examples 11 to 14 and Comparative Examples 9 and 10.

[0109] [Table 5]

[0110] [Table 6]

[0111] As can be seen from Tables 5 and 6, in Examples 11 to 14, the average value ΔH of the front and back deflection difference Y1-Y2 in the drawing direction Y in the evaluation areas C to E C-E was a negative value, and the evaluation of the total pitch deviation of the color filter and the evaluation of the color variation were all excellent, good or fair. In contrast, in Comparative Examples 9 and 10, the average value ΔH of the front and back deflection difference Y1-Y2 in the sheet drawing direction Y in the evaluation areas C to E C-E was a positive value, and it was impossible to evaluate the total pitch deviation and the color variation. From the above, it can be seen that the average value ΔH of the front and back deflection difference Y1-Y2 in the sheet drawing direction at least in the evaluation areas C to E C-E It can be confirmed that a negative value is effective in reducing the total pitch deviation of the thin film pattern.

[0112] In Examples 11 and 12, ΔH max -ΔH min and ΔV max -ΔV min In contrast, in Examples 13 and 14, ΔV max -ΔV min increased to a value exceeding 0.3 mm, and the evaluation of the total pitch deviation decreased to good. max -ΔH min and ΔV max -ΔV minIt can be confirmed that the total pitch deviation can be further reduced by reducing

[0113] In Example 12, ΔH A-G and ΔV A-G In contrast, in Examples 11, 13, and 14, ΔH A-G became negative, and the center and both ends of the drawing direction Y became bowl-shaped, but ΔV C-E and ΔV A-G was a positive value, and the bowl-shaped shape was not formed in the width direction X. As a result, in Examples 11, 13 and 14, the evaluation of the color variation was poor, being fair. This is because ΔH A-G and ΔV A-G It can be confirmed that the total pitch deviation can be further reduced by setting both of these to negative values. [Explanation of symbols]

[0114] 1. Glass substrate 1a Warranty side 1b Non-guaranteed side 1x width edge 1y Edge along the drawing direction 3. Sample glass 3a Warranty 3b Non-guaranteed side 3x width edges 3y Edge along the drawing direction 11 Manufacturing equipment 12 Molding furnace 13 Molded body 14 Annealing furnace 15 Cooling room 16 Cutting chamber 17 Edge roller 23 Annie Laura 24 Conveyor roller A~G evaluation area Gm molten glass Gr Glass Ribbon S Adsorption Plate Deflection in X1 and X2 width directions Deflection in the Y1 and Y2 plate pulling directions X Width direction Y Drawing direction

Claims

1. A rectangular glass substrate having a first side along a drawing direction and a second side along a width direction perpendicular to the drawing direction, the second side having a length of 1500 mm or more and a thickness of 1.3 mm or less, and one main surface serving as a nominal surface, When seven rectangular evaluation areas A, B, C, D, E, F, and G of the same size are set in order from one end side in the width direction, the average value ΔH of the front and back deflection differences in the sheet drawing direction of the evaluation areas C, D, and E in the center portion is calculated by the following formula (1): Ｃ－Ｅ is negative, The average value ΔV C-E of the difference in front and back deflection in the width direction of the evaluation areas C, D, and E in the central portion calculated by the following formula (2) is ΔV C-E ≦0.16, The evaluation areas B, C, D, E, and F are arranged in a line along the width direction without any gaps, The evaluation areas A and G are located at different positions in the plate drawing direction from the evaluation areas B, C, D, E, and F, The center side of the evaluation area A overlaps with the evaluation area B in the width direction, A glass substrate characterized in that the central side of the evaluation area G overlaps with the evaluation area F in the width direction. Difference in front and back deflection = (Y1 - Y2) [mm] (1) Y1: Deflection in the sheet drawing direction when the guaranteed surface of the sample glass corresponding to the evaluation area for measuring the difference in deflection between the front and back surfaces is facing downward. Y2: Deflection in the sheet drawing direction when the guaranteed surface is facing upward for the sample glass corresponding to the evaluation area for measuring the difference between the front and back deflections Difference in front and back deflection = (X1 - X2) [mm] (2) X1: The deflection in the width direction of the sample glass corresponding to the evaluation area for measuring the difference in deflection between the front and back surfaces when the guaranteed surface is facing downward. X2: Deflection in the width direction of the sample glass corresponding to the evaluation area for measuring the difference in deflection between the front and back surfaces when the guaranteed surface is facing upward.

2. The average value ΔH of the front and back deflection differences in the sheet drawing direction in the evaluation areas A, B, C, D, E, F, and G Ａ－Ｇ 2. The glass substrate according to claim 1, wherein is negative.

3. The respective values ​​of the front and back deflection differences in the sheet drawing direction in the evaluation areas A, B, C, D, E, F, and G are expressed as ΔH Ａ , ΔH Ｂ , ΔH Ｃ , ΔH Ｄ , ΔH Ｅ , ΔH Ｆ , ΔH Ｇ When this is the case, ΔH Ａ ~ΔH Ｇ At least ΔH Ｃ , ΔH Ｄ , ΔH Ｅ 3. The glass substrate according to claim 1, wherein each of the following is negative:

4. The maximum value ΔH of the difference in front and back deflection in the sheet drawing direction among the evaluation areas A, B, C, D, E, F, and G ｍａｘ and the minimum value ΔH of the difference in front and back deflection in the sheet drawing direction among the evaluation areas A, B, C, D, E, F, and G. ｍｉｎ Difference ΔH ｍａｘ -ΔH ｍｉｎ The glass substrate according to any one of claims 1 to 3, wherein the thickness is 0.5 mm or less.

5. The average value ΔV of the difference in front and back deflection in the width direction of the evaluation areas C, D, and E in the center Ｃ－Ｅ But, ΔV Ｃ－Ｅ 5. The glass substrate according to claim 1, wherein ≦0.

6. The average value ΔV of the difference in front and back deflection in the width direction of the evaluation areas A, B, C, D, E, F, and G Ａ－Ｇ 6. The glass substrate according to claim 1, wherein is negative.

7. The maximum value ΔV of the difference in front and back deflection in the width direction among the evaluation areas A, B, C, D, E, F, and G ｍａｘ and the minimum value ΔV of the difference in front and back deflection in the width direction among the evaluation areas A, B, C, D, E, F, and G. ｍｉｎ The difference ΔV ｍａｘ -ΔV ｍｉｎ The glass substrate according to any one of claims 1 to 6, wherein the thickness is 0.7 mm or less.

8. 8. The glass substrate according to claim 1, which is a low-alkali glass substrate for a display, having a strain point of 670°C or higher, a Young's modulus of 77 GPa or higher, and an amount of thermal shrinkage of 40 ppm or less when maintained at 500°C for 1 hour.

9. 9. The glass substrate according to claim 1, wherein the other main surface is a non-guaranteed surface, and the arithmetic mean roughness Ra of the non-guaranteed surface is 0.5 nm or less.

10. 10. The glass substrate according to claim 1, wherein the length of the second side is 2200 mm or more.

11. 11. The glass substrate according to claim 10, wherein the length of the first side is 1900 mm or more.

12. 12. The glass substrate according to claim 1, wherein the thickness is 0.5 mm or less.

13. A method for manufacturing an electronic device, comprising: a preparation step of preparing the glass substrate according to any one of claims 1 to 12; and a fabrication step of fabricating an electronic device using the glass substrate, the manufacturing step includes a suction step of suctioning the glass substrate with the guaranteed surface facing upward while the glass substrate is placed on a suction platen, The method for manufacturing an electronic device, wherein the suction step starts from a center of the glass substrate in the drawing direction and progresses suction of the glass substrate along the drawing direction.

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