Method for manufacturing a glass substrate and an electronic device

Abstract

The rectangular glass substrate 1 has a first side (1y) along the drawing direction (Y) and a second side (1x) along the width direction (X). The length of the second side (1x) is 1500 mm or more and the thickness is 1.3 mm or less. When seven evaluation regions A, B, C, D, E, F, and G having the same rectangular shape are sequentially set from one end side in the width direction (X) so as to have a positional relationship separated at equal intervals (L) in the width direction (X), the average value ΔH of the front-back deflection difference Y1 - Y2 in the drawing direction (Y) of the evaluation regions C, D, and E C‑E is negative.

Description

Technical Field

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

[0002] In the manufacturing process of electronic devices such as panel displays (e.g., liquid crystal displays, organic electroluminescent displays), a film forming process is included in which a multilayer thin film pattern is formed by lithography on a glass substrate (mother glass). These thin film pattern panels have become more complex and detailed as the display becomes more refined (e.g., Patent Documents 1 and 2).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-74582

[0006] Patent Document 2: International Publication No. 2017 / 150266 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In addition, a thin film pattern formed on a glass substrate (e.g., a pattern of a gate electrode) is evaluated by an index such as a total pitch. The total pitch is an index for determining whether the thin film pattern is formed within the design limits, and is managed by the difference between the designed distance and the measured distance between two predetermined points, to which, for example, a management mark is added. When the difference in the total pitch (hereinafter referred to as "total pitch deviation") becomes too large, it means that the thin film pattern is formed in a state significantly deviated from the design, and thus a reduction in the aperture ratio of pixels, light leakage between pixels, etc. may occur, and the quality of the electronic device may be significantly reduced.

[0009] As one of the reasons for the increase in the total pitch shift, there can be cited the irregular positional shift of the glass substrate when the glass substrate is arranged in the exposure apparatus during the film forming process of the thin film pattern. Specifically, the glass substrate is not actually an ideal plane and has a shape slightly deviated from the ideal plane due to the influence of annealing conditions. Therefore, when the glass substrate has an inappropriate shape, during the process of adsorbing the glass substrate onto the adsorption platform of the exposure apparatus, a force that deforms the glass substrate in imitation of the adsorption platform is applied in an inappropriate direction, and the position of the glass substrate changes irregularly. In this state, when exposure is performed, the exposure error becomes large, and as a result, the total pitch shift of the thin film pattern formed on the glass substrate becomes large. In addition, after the glass substrate is coated with a black matrix (BM) film in particular and patterned using a photomask, and then in the color filter process of coating RGB three-color color filters, if a pattern shift occurs when forming a higher definition display, color deviation (non-uniformity) may sometimes occur in the final screen display.

[0010] The problem of the present invention is to provide a glass substrate capable of reliably reducing the total pitch shift of a thin film pattern. Another problem of the present invention is to provide an electronic device including a glass substrate in which the total pitch shift of the thin film pattern is reliably reduced.

[0011] Solution to the problem

[0012] (a) The present invention made to solve the above problems is a glass substrate having a rectangular shape and having a first side along the draw plate direction and a second side along the width direction orthogonal to the draw plate direction, the length of the second side being 1500 mm or more and the thickness being 1.3 mm or less, and one main surface being a guarantee surface.

[0013] The glass substrate is characterized in that

[0014] When seven evaluation regions A, B, C, D, E, F, and G having the same rectangular shape are sequentially set from one end side in the width direction, the average value ΔH of the front-back deflection differences in the draw plate direction of the evaluation regions C, D, and E in the central part obtained by the following mathematical formula (1) C-E is negative.

[0015] Front-back deflection difference = (Y1 - Y2) [mm] (1)

[0016] Y1: The deflection in the draw plate direction when the guarantee surface is downward for the sample glass corresponding to the evaluation region where the front-back deflection difference is measured.

[0017] Y2: The deflection in the draw plate direction when the guarantee surface is upward for the sample glass corresponding to the evaluation region where the front-back deflection difference is measured.

[0018] In this way, with the guaranteed surface facing upward, the central portion in the width direction corresponding to the evaluation regions C, D, and E of the glass substrate becomes a bowl shape along the draw bar direction. Here, when observing an arbitrary linear region (cross-section) along the draw bar direction in the glass substrate, this linear region passes through the same location during annealing and is drawn by the draw bar. That is, even if the position in the draw bar direction is different, the annealing conditions such as the thermal history of this linear region along the draw bar direction are substantially the same. Therefore, there is a tendency that if the position in the width direction is the same, the shape in the draw bar direction is substantially the same. Thus, with the above structure, with the guaranteed surface facing upward, the central portion in the width direction of the glass substrate is not limited to the range of the evaluation region, but becomes a bowl shape along the draw bar direction within the substantially entire length range in the draw bar direction. For a glass substrate with such a bowl shape, when adsorbing the non-guaranteed surface on the back side of the guaranteed surface using the adsorption platform, the adsorption smoothly progresses sequentially from the central portion toward the end portion in the draw bar direction with the central portion in the draw bar direction as the starting point. Therefore, the generation of position deviation can be suppressed. That is, the total pitch deviation of the thin film pattern formed on the guaranteed surface of the glass substrate can be reliably reduced.

[0019] (b) In the structure of the above (a), preferably, the average value ΔH of the front-back deflection difference in the draw bar direction of the evaluation regions A, B, C, D, E, F, and G A-G is negative.

[0020] In this way, substantially the entire width direction of the glass substrate becomes a bowl shape within the substantially entire length range in the draw bar direction. Thus, when adsorbing the non-guaranteed surface of the glass substrate using the adsorption platform, the situation where position deviation occurs in the glass substrate can be further suppressed. Therefore, the total pitch deviation of the thin film pattern can be further reduced.

[0021] (c) In the structure of the above (a) or (b), preferably, when setting the values of the front-back deflection differences in the draw bar direction of the evaluation regions A, B, C, D, E, F, and G as ΔH A , ΔH B , ΔH C , ΔH D , ΔH E , ΔH F , ΔH G , at least ΔH A ~ΔH G among them, at least ΔH C , ΔH D , ΔH E are respectively negative.

[0022] As a result, the in-plane shape change of the glass substrate is small, and it becomes a bowl-shaped shape with a gentle shape change. Therefore, when the non-guaranteed surface of the glass substrate is adsorbed by the adsorption platform, the occurrence of position deviation in the glass substrate can be further suppressed, and thus the total pitch deviation of the thin film pattern can be further reduced.

[0023] (d) In any of the structures in (a) to (c) above, preferably, the maximum value ΔH of the front-back deflection difference in the drawbar direction in the evaluation regions A, B, C, D, E, F, G max and the minimum value ΔH of the front-back deflection difference in the drawbar direction in the evaluation regions A, B, C, D, E, F, G min The difference ΔH max -ΔH min is 0.5 mm or less.

[0024] In this way, the deviation of the front-back deflection difference in the drawbar direction can be reduced. That is, a large shape change of the glass substrate in the drawbar direction can be suppressed, and therefore, when the non-guaranteed surface of the glass substrate is adsorbed by the adsorption platform, the occurrence of insufficient adsorption and poor adsorption can be suppressed. Thus, it can contribute to the reduction of the total pitch deviation of the thin film pattern.

[0025] (e) In any of the structures in (a) to (d) above, preferably, the average value ΔV of the front-back deflection difference in the width direction of the evaluation regions C, D, E in the central portion obtained by the following mathematical formula (2) C-E is ΔV C-E ≤0,

[0026] Front-back deflection difference = (X1 - X2) [mm] (2)

[0027] X1: The deflection in the width direction when the guaranteed surface of the sample glass corresponding to the evaluation region for measuring the front-back deflection difference is facing downwards,

[0028] X2: The deflection in the width direction when the guaranteed surface of the sample glass corresponding to the evaluation region for measuring the front-back deflection difference is facing upwards.

[0029] In this way, in the state where the guaranteed surface of the glass substrate is facing upwards, the central portion in the width direction corresponding to the evaluation regions C, D, E also becomes a bowl-shaped shape or a substantially flat shape in the width direction. Therefore, when the non-guaranteed surface of the glass substrate is adsorbed by the adsorption platform, the occurrence of position deviation in the glass substrate can be further reduced. That is, the total pitch deviation of the thin film pattern can be further reduced.

[0030] (f) In the structure of (e) above, preferably, the average value ΔV of the front-back deflection difference in the width direction of the evaluation regions A, B, C, D, E, F, G A-G is negative.

[0031] In this way, in a state where the guaranteed surface faces upward, the entire width direction of the glass substrate also forms a bowl-shaped shape in the width direction. Therefore, when the non-guaranteed surface of the glass substrate is adsorbed by the adsorption platform, the occurrence of position deviation in the glass substrate can be further reduced, and thus the total pitch deviation of the thin film pattern can be further reduced.

[0032] (g) In the structure of the above (e) or (f), preferably, the maximum value ΔV of the front-back deflection difference in the width direction in the evaluation regions A, B, C, D, E, F, and G max and the minimum value ΔV of the front-back deflection difference in the width direction in the evaluation regions A, B, C, D, E, F, and G min The difference ΔV max -ΔV min is 0.7 mm or less.

[0033] In this way, the deviation of the front-back deflection difference in the width direction can be reduced. That is, a large shape change of the glass substrate in the width direction can be suppressed, and thus when the non-guaranteed surface of the glass substrate is adsorbed by the adsorption platform, the occurrence of insufficient adsorption and poor adsorption can be more reliably suppressed. Therefore, the total pitch deviation of the thin film pattern can be further reduced.

[0034] (h) In any of the structures of the above (a) to (g), preferably, the glass substrate is an alkali-free glass substrate for a display, the strain point is 670 °C or higher, the Young's modulus is 77 GPa or higher, and the thermal shrinkage amount when maintained at 500 °C for one hour is 40 ppm or less.

[0035] (i) In any of the structures of the above (a) to (h), preferably, the arithmetic mean roughness Ra of the non-guaranteed surface is 0.5 nm or less.

[0036] (j) In any of the structures of the above (a) to (i), preferably, the length of the second side is 2200 mm or more.

[0037] (k) In the structure of the above (j), more preferably, the length of the first side is 1900 mm or more.

[0038] (1) In any of the structures of the above (a) to (k), preferably, the thickness of the glass substrate is 0.5 mm or less.

[0039] (m) The present invention made to solve the above problems is a method for manufacturing an electronic device, comprising: a preparation step of preparing a glass substrate appropriately having the structures of the above (a) to (1); and a manufacturing step of manufacturing an electronic device using the glass substrate.

[0040] The manufacturing method of the electronic device is characterized in that

[0041] The manufacturing process includes an adsorption process of adsorbing a glass substrate with the guarantee surface facing upward while being placed on an adsorption platform.

[0042] In the adsorption process, starting from the central part in the pulling direction of the glass substrate, the adsorption of the glass substrate is advanced along the pulling direction.

[0043] In this way, for the same reasons as described above, an electronic device with a glass substrate having a reliably reduced total pitch deviation of the thin film pattern can be manufactured.

[0044] Advantages of the Invention

[0045] According to the present invention, a glass substrate capable of reliably reducing the total pitch deviation of the thin film pattern and an electronic device with a glass substrate having a reliably reduced total pitch deviation of the thin film pattern can be provided. Brief Description of the Drawings

[0046] Figure 1 is a plan view of a glass substrate according to an embodiment of the present invention.

[0047] Figure 2 is a plan view for explaining a method of measuring the front-back warpage difference in the pulling direction of a specimen glass cut out from the glass substrate.

[0048] Figure 3 is a side view of the specimen glass for measuring the front-back warpage difference by the method shown in Figure 2 when viewed from the direction of arrow I.

[0049] Figure 4 is a plan view for explaining a method of measuring the front-back warpage difference in the width direction of a specimen glass cut out from the glass substrate.

[0050] Figure 5 is a side view of the specimen glass for measuring the front-back warpage difference by the method shown in Figure 4 when viewed from the direction of arrow II.

[0051] Figure 6A is a diagram showing the adsorption process included in the manufacturing method of an electronic component according to an embodiment of the present invention, and showing the initial state of the adsorption process.

[0052] Figure 6B is a diagram showing the adsorption process included in the manufacturing method of an electronic component according to an embodiment of the present invention, and showing the intermediate state of the adsorption process.

[0053] Figure 6CIt is a diagram showing the adsorption process included in the manufacturing method of an electronic component according to an embodiment of the present invention, and shows the state at the end of the adsorption process.

[0054] Figure 7 It is a side sectional view showing a manufacturing apparatus for a glass substrate according to an embodiment of the present invention.

[0055] Figure 8 It is a front sectional view showing a manufacturing apparatus for a glass substrate according to an embodiment of the present invention.

[0056] Figure 9 is Figure 7 an enlarged view around the annealing roller. Detailed Embodiment

[0057] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0058] (First Embodiment)

[0059] As Figure 1 shown, the glass substrate 1 of the present embodiment is manufactured by a known forming method accompanied by a drawing plate such as the overflow down-draw method, the slot down-draw method, the redraw method, or the float method. In the present embodiment, a glass ribbon is formed by the overflow down-draw method and cut out from the glass ribbon, thereby obtaining a glass substrate 1 having a rectangular shape with a specified size. In the case of the overflow down-draw method, the front and back surfaces of the formed glass ribbon are formed without contacting any part of the forming body during the forming process, and thus there is an advantage that a forged surface having a very smooth surface property is obtained. It should be noted that the glass substrate 1 formed by the overflow down-draw method has a forming confluence surface in the central region in the plate thickness direction.

[0060] The glass substrate 1 has a first side 1y along the drawing plate direction Y and a second side 1x along the width direction X orthogonal to the drawing plate direction Y. For the drawing plate direction Y of the glass substrate 1, for example, by irradiating light from a light source (such as a xenon lamp) while adjusting the angle of the glass substrate 1 in a dark room and projecting the transmitted light onto a screen, a striped fringe pattern can be observed. Therefore, even in the state of the formed glass substrate 1, the drawing plate direction Y can be determined during forming.

[0061] In the glass substrate 1, one main surface becomes the guaranteed surface 1a, and the other main surface becomes the non-guaranteed surface 1b. The guaranteed surface 1a is a surface that guarantees a specified quality and forms a thin film pattern during the manufacture of an electronic device, and is kept in a non-contact state as much as possible during each process such as the handling and processing of the glass substrate 1. In this case, the non-guaranteed surface 1b located on the back side of the guaranteed surface 1a is a contact surface that is contacted by a handling device or the like during handling or each process such as processing.

[0062] As the glass substrate 1, for example, a low-alkali glass substrate for a display can be cited. Here, as the "display", for example, a liquid crystal display, an organic EL display, etc. can be cited. In addition, "low-alkali glass" means glass with a small amount of alkali components (alkali metal oxides) or glass that substantially does not contain alkali components.

[0063] As the composition of the specific low-alkali glass, it preferably contains 60 to 75% of SiO2, 5 to 20% of Al2O3, 0 to 15% of B2O3, 0 or more and 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 in terms of mol%. Among them, the following glass composition examples are particularly preferred.

[0064] As an example of the first glass composition, it preferably contains 60 to 70% of SiO2, 9.5 to 17% (especially 11 to 15%) of Al2O3, 0 to 9% (especially 5 to 7%) of B2O3, 0 or more and less than 1% (especially 0 to 0.5%) of Li2O + Na2O + K2O, 0 to 8% (especially 2 to 6%) of MgO, 2 to 15% (especially 6 to 11%) of CaO, 0 to 10% (especially 0.1 to 3%) of SrO, and 0.1 to 5% of BaO in terms of mol%. In this way, the liquid-phase viscosity and Young's modulus can be improved. As a result, it is easy to fabricate a thin-walled glass plate G, and it is easy to reduce the amount of deflection of the glass plate G.

[0065] As an example of the second glass composition, it preferably contains 62 to 72% of SiO2, 9.5 to 16% (especially 11 to 15%) of Al2O3, 1 to 8% (especially 2 to 4%) of B2O3, 0 or more and less than 1% (especially 0 to 0.5%) of Li2O + Na2O + K2O, 1 to 9% (especially 4 to 8%) of MgO, 2 to 10% (especially 3 to 8%) of CaO, 0.1 to 5% (especially 1 to 3%) of SrO, and 0.1 to 5% (especially 1 to 3%) of BaO in terms of mol%. In this way, the liquid-phase viscosity and Young's modulus can be improved. As a result, it is easy to fabricate a thin-walled glass plate G, and it is easy to reduce the amount of deflection of the glass plate G.

[0066] As an example of the third glass composition, it preferably contains 67 to 77% of SiO2, 9 to 14% of Al2O3, 0 to 3% (especially 0 or more and less than 1%) of B2O3, 0 or more and less than 1% (especially 0 to 0.5%) of Li2O + Na2O + K2O, 0 to 5% (especially 2 to 5%) of MgO, 0 to 10% (especially 6 to 9%) of CaO, 0 to 5% of SrO, and 0 to 7% (especially 3 to 6%) of BaO in terms of mol%. In this way, it is easy to raise the strain point to 730 °C or higher.

[0067] The maximum deflection amount Y max (mm) in the case of two-point supporting the glass substrate 1 can be defined by the following mathematical formula (3).

[0068] Y max = 5g / 32 × d(1 - v 2 ) / E × 10 -9 × L 4 / t 2 (3)

[0069] Here, g: gravitational acceleration [m / S 2 , d: density of the glass substrate [g / cm 3 , E: Young's modulus [GPa], v: Poisson's ratio, L: distance between the support points [mm], t: plate thickness of the glass substrate [mm].

[0070] As described in the mathematical formula (3), since the deflection amount of the glass substrate 1 is inversely proportional to the square of the plate thickness, the thinner the glass substrate 1, the more significant the influence on deflection. Especially in the case of the thin glass substrate 1 with a thickness of 0.5 mm or less, the glass substrate 1 is easily deflected. Therefore, in the case of the thin glass substrate 1, the deflection of the glass substrate 1 has a greater influence on the shape of the glass substrate 1 in the film formation process.

[0071] As described in the mathematical formula (3), the deflection amount 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, in the case of the larger glass substrate 1, the deflection of the glass substrate 1 also has a greater influence on the shape of the glass substrate 1 in the film formation process.

[0072] In the mathematical formula (3), the Poisson's ratio is approximately 0.2 and there is no difference in the case of the glass substrate for a display, so the property that has a greater influence on deflection becomes the Young's modulus. A glass material with a large Young's modulus can suppress the deflection deformation of the glass substrate 1, so it is possible to suppress the deformation of the glass substrate 1 in display processes such as the heat treatment process and the handling process. Therefore, it can be suitably used as a glass substrate for a high-precision display.

[0073] The length of the first side 1y of the glass substrate 1 is preferably 1300 mm or more, preferably 1500 mm or more, preferably 1800 mm or more, preferably 1900 mm or more, and particularly preferably 2100 mm or more. Additionally, the length of the second side 1x of the glass substrate 1 is preferably 1500 mm or more, preferably 1800 mm or more, preferably 2150 mm or more, preferably 2200 mm or more, and particularly preferably 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 the present 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.

[0074] The thickness of the glass substrate 1 is preferably 1.3 mm or less, preferably 1.0 mm or less, preferably 0.7 mm or less, and particularly preferably 0.5 mm or less. On the other hand, the thickness of the glass substrate 1 is preferably 0.2 mm or more, and particularly preferably 0.3 mm or more.

[0075] The Young's modulus of the glass substrate 1 is preferably 77 GPa or more, preferably 80 GPa or more, and particularly preferably 83 GPa or more. It should be noted that the "Young's modulus" refers to the value measured according to the dynamic elastic modulus measurement method (resonance method) based on JIS R1602.

[0076] In addition, in the case of a heat treatment process that involves heating at a high temperature after film formation on the glass substrate 1, shrinkage (compression) of the glass substrate 1 due to the heat treatment occurs. Therefore, when the glass substrate 1 is supplied to a manufacturing process for, for example, a high-definition display device, it preferably has the characteristic of a small shrinkage amount.

[0077] The strain point of the glass substrate 1 is preferably 670 °C or more, preferably 700 °C or more, and particularly preferably 720 °C or more. In this way, in a manufacturing process for, for example, a high-definition display device, particularly for the manufacture of oxide TFTs or low-temperature polycrystalline silicon TFTs, it is easy to suppress thermal shrinkage and deformation of the glass substrate 1. On the other hand, when the strain point of the glass substrate 1 is too high, the temperature in the forming process, particularly in the annealing process, becomes too high, making it difficult to control the shape of the glass substrate 1 and the manufacturing cost is likely to increase. Thus, the strain point of the glass plate 1 is preferably 800 °C or less, preferably 790 °C or less, and particularly preferably 780 °C or less. It should be noted that the "strain point" is the value measured based on the methods of ASTM C336 and C338.

[0078] When the glass plate 1 is maintained at 500 °C for one hour, the thermal shrinkage amount is preferably 40 ppm or less, more preferably 30 ppm or less, and particularly preferably 20 ppm or less. In this way, even in the case of a heat treatment step of heating at a high temperature after film formation on the glass substrate 1, the shrinkage (compression) of the glass substrate 1 caused by the heat treatment is suppressed. Therefore, it can be suitably used as a glass substrate for high-definition displays. It should be noted that the "thermal shrinkage amount" is measured by the following method. First, as a specimen for measurement, a rectangular specimen of 160 mm × 30 mm is prepared. Near the end of the long side direction of the rectangular specimen, a mark is made using #1000 waterproof abrasive paper at a distance of 20 to 40 mm, and the specimen is broken along the direction orthogonal to the mark to obtain two test pieces. After heat-treating one of the broken test pieces under specified conditions, the other test piece that has not been heat-treated is placed side by side with the heat-treated test piece and fixed with tape or the like. In this state, the position offset amounts (ΔL1, ΔL2) of the marks are read using a laser microscope, and the thermal shrinkage amount is calculated by the following formula (4).

[0079] Thermal shrinkage amount [ppm] = (ΔL1 [μm] + ΔL2 [μm]) / 160 × 10 -3 (4)

[0080] Specifically, the shape of the glass substrate 1 in the orientation along the pulling plate direction Y and the shape in the orientation along the width direction X can be evaluated using the front-back flexure difference.

[0081] First, a method for evaluating the shape of the glass substrate 1 in the orientation along the pulling plate direction Y using the front-back flexure difference Y1 - Y2 will be described.

[0082] As Figure 1 shown, seven rectangular evaluation regions A to G with different positions in the direction along the width direction X are set for one glass substrate 1. The evaluation regions A to G are set in sequence from one end side in the width direction X. The evaluation regions B to F are arranged in a row along the width direction X without gaps. In addition, the positions of the evaluation regions A and G in the pulling plate direction Y are different from those of the evaluation regions B to F. The center side of the evaluation region A overlaps with the position in the width direction of the evaluation region B, and the center side of the evaluation region G overlaps with the position in the width direction of the evaluation region F. At this time, each of the evaluation regions A to G is set within an effective region (not shown) of the guaranteed surface of the glass substrate 1, for example, a region where a thin film pattern is formed through a film formation process. The size of the effective region in the width direction X in the present embodiment is 2500 mm.

[0083] Here, in the present embodiment, each of the evaluation regions A to G has a rectangular shape with a length 2y of the side along the draw plate direction Y being 500 mm and a length 2x of the side along the width direction X being 400 mm. The overlapping length of the evaluation region A and the evaluation region B in the width direction and the overlapping length of the evaluation region G and the evaluation region F in the width direction are 150 mm. When the dimension of the effective region along the width direction X is not 2500 mm, the length 2x of the side along the width direction X is set to 16% of the dimension of the effective region along the width direction X. In addition, the overlapping length of the evaluation region A and the evaluation region B in the width direction and the overlapping length of the evaluation region G and the evaluation region F in the width direction are set to 6% of the dimension of the effective region along the width direction X. The length 2y of the side along the draw plate direction Y is 125% of the length 2x of the side along the width direction X.

[0084] Specimen glasses (glass pieces) 3 corresponding to the positions and sizes of the respective evaluation regions A to G are extracted from the glass substrate 1, and for one glass substrate 1, seven specimen glasses 3 corresponding to the evaluation regions A to G are obtained. That is, the specimen glass 3 has a side 3y along the draw plate direction Y corresponding to the side 2y of the evaluation regions A to G and a side 3x along the width direction X corresponding to the side 2x of the evaluation regions A to G.

[0085] After thus preparing seven specimen glasses 3, the front-back deflection difference Y1 - Y2 in the draw plate direction Y of each specimen glass 3 is measured. Specifically, as Figure 2 shown, with the non-guaranteed surface 3b of the specimen glass 3 (the surface on the same side as the non-guaranteed surface 1b of the glass substrate 1) facing upward, the two end portions of the specimen glass 3 in the draw plate direction Y are supported by a pair of support members 4. At this time, when the length of the side 3y along the draw plate direction Y of the specimen glass 3 is 500 mm and the length of the side 3x along the width direction X is 400 mm, the support span M of the pair of support members 4 for supporting the specimen glass 3 is set to 480 mm, and in other cases, it is set to a value obtained by subtracting 20 mm from the length of the side 3y of the specimen glass 3 parallel to the draw plate direction Y. In this state, as Figure 3 shown, the magnitude of the first deflection Y1 (the state shown by the solid line in the figure) of the specimen glass 3 in the draw plate direction Y is measured. 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, when the support span M is M1 (any value) mm, it is converted by Y1×(350 / M1).

[0086] Similarly, in a state where the sample glass 3 is reversed front to back and the guarantee surface 3a of the sample glass 3 (the surface on the same side as the guarantee surface 1a of the glass substrate 1) faces upward, both end portions of the sample glass 3 in the draw plate direction Y are supported by a pair of support members 4. In this state, as Figure 3 shown, the magnitude of the second flexure Y2 (the state indicated by the one-dot chain line in the figure) in the draw plate direction Y of the sample glass 3 is measured. The measured magnitude of the second flexure Y2 is converted to the second flexure Y2 when the support span M is 350 mm.

[0087] In this way, after measuring the first flexure Y1 and the second flexure Y2, the second flexure Y2 is subtracted from the first flexure Y1 to obtain the front-back flexure difference Y1 - Y2 in the draw plate direction Y.

[0088] By performing the above operations on all the sample glasses 3 corresponding to the respective evaluation regions A to G, the shape in the draw plate direction Y in each of the evaluation regions A to G can be grasped. For example, as Figure 3 shown, when the first flexure Y1 is smaller than the second flexure Y2 and the front-back flexure difference Y1 - Y2 is negative, the flexure direction in the draw plate direction Y of the sample glass 3 in the glass substrate 1 is the direction in which the guarantee surface 3a is recessed, and its magnitude can be evaluated by the absolute value of the front-back flexure difference Y1 - Y2. On the other hand, when the first flexure Y1 is larger than the second flexure Y2 and the front-back flexure difference Y1 - Y2 is positive (illustration omitted), the flexure direction in the draw plate direction Y of the sample glass 3 in the glass substrate 1 is the direction in which the non-guarantee surface 3b is recessed, and its magnitude can be evaluated by the absolute value of the front-back flexure difference Y1 - Y2. Here, when observing an arbitrary linear region (cross-section) along the draw plate direction Y in the glass substrate 1, even if the position in the draw plate direction Y is different, the annealing conditions at each point on this linear region are substantially the same. Therefore, there is a tendency that the shape in the draw plate direction Y is substantially the same as long as the position in the width direction X is the same. Thus, by obtaining the front-back flexure difference Y1 - Y2 for the sample glasses 3 corresponding to the respective evaluation regions A to G, the shape in the draw plate direction Y of the entire effective region of the glass substrate 1 can be indirectly grasped.

[0089] Next, a method for evaluating the shape of the glass substrate 1 in the width direction X using the front-back flexure difference X1 - X2 will be described.

[0090] After preparing seven sample glasses 3 corresponding to the Figure 1 shown evaluation regions A to G, the front-back flexure difference X1 - X2 in the width direction X of each sample glass 3 is measured. The prepared sample glasses 3 can be the sample glasses 3 used when evaluating the shape in the draw plate direction Y. Specifically, as Figure 4As shown, with the non-guaranteed surface 3b of the specimen glass 3 facing upward, both ends of the specimen glass 3 in the width direction X are supported by a pair of support members 5. At this time, when the length of the side 3y along the drawplate direction Y is 500 mm and the length of the side 3x along the width direction X is 400 mm, the support span N of the pair of support members 5 for supporting the specimen glass 3 is set to 380 mm. In other cases, it is set to the value obtained by subtracting 20 mm from the length of the side 3x of the specimen glass 3 parallel to the width direction X. In this state, as Figure 5 shown, the magnitude of the first flexure X1 (the state shown by the solid line in the figure) in the width direction X of the specimen glass 3 is measured. The measured magnitude of the first flexure X1 is converted to the first flexure X1 when the support span N is 350 mm.

[0091] Similarly, with the specimen glass 3 turned front to back and the guaranteed surface 3a of the specimen glass 3 facing upward, both ends of the specimen glass 3 in the width direction X are supported by a pair of support members 5. In this state, as Figure 5 shown, the magnitude of the second flexure X2 (the state shown by the one-dot chain line in the figure) in the width direction X of the specimen glass 3 is measured. The measured magnitude of the second flexure X2 is converted to the second flexure X2 when the support span N is 350 mm.

[0092] In this way, after measuring the first flexure X1 and the second flexure X2, the first flexure X1 is subtracted from the second flexure X2 to obtain the front-back flexure difference X1 - X2 in the width direction X.

[0093] By performing the above operations on all the specimen glasses 3 corresponding to each evaluation region A - G, the shape in the width direction X of each evaluation region A - G can be grasped. For example, as Figure 5As shown, when the first flexure X1 is smaller than the second flexure X2 and the back-to-front flexure difference X1 - X2 is negative, the flexure direction in the width direction X of the specimen glass 3 in the glass substrate 1 is the direction in which the guaranteed surface 3a is recessed, and its magnitude can be evaluated by the absolute value of the back-to-front flexure difference X1 - X2. On the other hand, when the first flexure X1 is larger than the second flexure X2 and the back-to-front flexure difference X1 - X2 is positive (illustration omitted), the flexure direction in the width direction X of the specimen glass 3 in the glass substrate 1 is the direction in which the non-guaranteed surface 3b is recessed, and its magnitude can be evaluated by the absolute value of the back-to-front flexure difference X1 - X2. Here, when observing an arbitrary linear region (cross-section) along the width direction X in the glass substrate 1, if the position in the width direction X is different, the annealing conditions at each location on this linear region are substantially different. However, since each evaluation region A - G extends over the entire width direction X of the effective region of the glass substrate 1, as long as the back-to-front flexure difference X1 - X2 is obtained for the specimen glass 3 corresponding to each evaluation region A - G, the shape of the glass substrate 1 in the width direction X of the entire effective region can be directly grasped.

[0094] If the shape of the glass substrate 1 of the present embodiment is evaluated using the above-mentioned back-to-front flexure difference, it has the following shape quality.

[0095] That is, in the glass substrate 1, the average value ΔH of the back-to-front flexure differences Y1 - Y2 in the draw direction Y of the specimen glass 3 corresponding to the evaluation regions C, D, and E located at the central portion in the width direction X C-E is negative. Thus, in the state where the guaranteed surface 1a of the glass substrate 1 is upward, the central portion in the width direction X becomes a bowl-shaped (concave-shaped) along the draw direction Y within the substantially entire length range of the draw direction Y. And if the glass substrate 1 is of such a bowl-shaped, for example, as shown in FIGS. 6(a) - (c), in the state where the guaranteed surface 1a is upward, when the non-guaranteed surface 1b on its back side is adsorbed using the adsorption stage S, the adsorption smoothly progresses successively along the draw direction Y starting from the central portion 1c in the draw direction Y. Therefore, the position deviation of the glass substrate 1 on the adsorption stage S can be suppressed. That is, the total pitch deviation of the thin film pattern formed on the guaranteed surface 1a of the glass substrate 1 can be reliably reduced.

[0096] It is preferable that the glass substrate 1 has an average value ΔH of the back-to-front flexure differences Y1 - Y2 in the draw direction Y of the specimen glass 3 corresponding to all the evaluation regions A - G A-G being negative. Thus, the entire width direction X of the effective region of the glass substrate 1 becomes a bowl-shaped within the substantially entire length range of the draw direction Y. Therefore, the generation of the position deviation of the glass substrate 1 can be further suppressed. It should be noted that it is not necessary for all the values of the back-to-front flexure differences Y1 - Y2 of the evaluation regions A - G to be negative, and some of the values can be positive.

[0097] The glass substrate 1 is preferably such that when the values of the front-back deflection differences in the pulling plate direction Y of the evaluation regions A to G are set as ΔH A , ΔH B , ΔH C , ΔH D , ΔH E , ΔH F , ΔH G , at ΔH A ~ΔH G , at least ΔH C , ΔH D , ΔH E are negative respectively. Particularly preferably, at least 2 / 3 or more of the regions including ΔH C , ΔH D , ΔH E corresponding to the central portion are all negative. Thereby, the in-plane shape change of the glass substrate 1 is small, and it becomes a bowl shape with a gently changing shape.

[0098] The glass substrate 1 is preferably such that the maximum value ΔH of the front-back deflection difference Y1 - Y2 in the pulling plate direction Y of the test glass 3 corresponding to all the evaluation regions A to G max and the minimum value ΔH of the front-back deflection difference Y1 - Y2 in the pulling plate direction Y of the test glass 3 corresponding to all the evaluation regions A to G min have a difference ΔH max -ΔH min of 0.5 mm or less, and more preferably 0.3 mm or less. Thereby, the deviation of the front-back deflection difference Y1 - Y2 in the pulling plate direction Y is reduced. That is, a large shape change of the glass substrate 1 in the pulling plate direction Y can be suppressed, and thus insufficient adsorption or poor adsorption can be suppressed when the non-guaranteed surface 1b of the glass substrate 1 is adsorbed by the adsorption platform S.

[0099] The glass substrate 1 is preferably such that the average value ΔV of the front-back deflection difference X1 - X2 in the width direction X of the test glass 3 corresponding to the evaluation regions C, D, and E located at the central portion in the width direction X C-E is ΔV C-E ≤0. Thereby, the central portion in the width direction X of the glass substrate 1 is also in a bowl shape or substantially flat shape in the width direction X in the state where the guaranteed surface 1a is upward. Thus, generation of position deviation of the glass substrate 1 on the adsorption platform S can be more reliably suppressed. By setting ΔV C-E <0, the adsorption from the central portion to the peripheral portion of the glass substrate 1 advances without delay, and thus the shape of the adsorbed glass substrate is flat and stable. Therefore, it is preferably ΔV C-E <0.

[0100] The glass substrate 1 is preferably the average value ΔV of the front-back deflection difference X1 - X2 in the width direction X of the sample glass 3 corresponding to all the evaluation regions A to G. A-G It is negative. Thus, the entire width direction X of the effective region of the glass substrate 1 also has a bowl-shaped form along the width direction X. Therefore, it is possible to more reliably suppress the occurrence of position deviation of the glass substrate 1 on the adsorption platform S. It should be noted that it is not necessary for the values of the front-back deflection differences X1 - X2 of all the evaluation regions A to G to be negative, and some of the values can be positive.

[0101] The glass substrate 1 is preferably the maximum value ΔV of the front-back deflection difference X1 - X2 in the width direction X of the sample glass 3 corresponding to all the evaluation regions A to G. max and the minimum value ΔV of the front-back deflection difference X1 - X2 in the width direction X of the sample glass 3 corresponding to all the evaluation regions A to G. min The difference ΔV max -ΔV min is 0.7 mm or less, more preferably 0.4 mm or less, and most preferably 0.3 mm or less. Thus, the deviation of the front-back deflection difference X1 - X2 in the width direction X is reduced. That is, it is possible to suppress a large shape change of the glass substrate 1 in the width direction X, and therefore it is possible to suppress the occurrence of insufficient adsorption and poor adsorption when the non-guaranteed surface 1b of the glass substrate 1 is adsorbed by the adsorption platform S.

[0102] Here, as a cause of the total pitch deviation due to the irregular position deviation of the glass substrate 1, it also has an influence that the roughness of the non-guaranteed surface 1b of the glass substrate 1 (the arithmetic mean roughness Ra is, for example, 0.5 nm or less) is very small. Especially in the case where the glass substrate 1 is formed by the overflow down-draw method, the roughness of the non-guaranteed surface 1b of the glass substrate 1 is likely to become small. When the roughness of the non-guaranteed surface 1b of the glass substrate 1 is small, static electricity is generated on the platform during film formation and the slidability of the glass substrate 1 becomes poor, which easily hinders the glass substrate 1 from following the platform. In particular, in the case of the glass substrate 1 having a convex shape upward where the front-back deflection difference at the central portion of the glass substrate 1 is positive and / or the front-back deflection difference at the peripheral portion is negative, the deflection at the peripheral portion becomes relatively large, and the expansion of the glass at the peripheral portion on the platform is suppressed. As a result, adsorption is advanced in a state where the glass substrate 1 has not stably moved to the desired position, and a gap is generated between the glass substrate 1 and the platform, which may be a cause of position deviation (total pitch deviation). However, in the present invention, as described above, the shape (deflection) of the glass substrate 1 is managed, so that even in such a case where the roughness of the non-guaranteed surface 1b is small (the arithmetic mean roughness Ra is 0.5 nm or less), the total pitch deviation can be suppressed. It should be noted that the "arithmetic mean roughness Ra" is the arithmetic mean roughness obtained in accordance with JIS R1683:2014 and is measured by an atomic force microscope.

[0103] Next, a method for manufacturing an electronic device using the glass substrate 1 having the above structure is 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 smart phone), a tablet computer, a digital camera, a touch panel display, a large television, etc.

[0104] The method for manufacturing such an electronic device includes: a preparation step of preparing the glass substrate 1 described above; and a production step of producing the electronic device using the glass substrate 1 .

[0105] Although not shown in the figure, the manufacturing process includes a film forming process of forming a thin film pattern on the securing surface 1 a of the glass substrate 1 by photolithography.

[0106] For example, in the case of manufacturing a thin film transistor (TFT), the film forming process includes in sequence: a metal film forming process, forming a metal film (such as copper, aluminum, etc.) that becomes the raw material of the thin film pattern (transistor wiring) on ​​the guaranteed surface 1a of the glass substrate 1; a resist film forming process, forming a resist film on the metal film; an exposure process, irradiating ultraviolet light or the like to the resist film to transfer the pattern of the photomask; a developing process, removing the exposed part (positive type) or the non-exposed part (negative type) of the resist layer; an etching process, removing the metal film in the part not covered by the resist film; and a resist film removal process, removing the resist film.

[0107] For example, in the case of color filter manufacturing, the process includes forming a resist film, forming an R filter film, forming a G filter film, and forming a B filter film. Each of these film forming processes includes a film forming process, an exposure process, and a development process.

[0108] The exposure process is a pre-process of irradiating light through a photomask, including: Figures 6A to 6C The adsorption process shown in the figure is to use the adsorption platform S to adsorb the non-guaranteed surface 1b of the glass substrate 1 while placing the glass substrate 1 with the guaranteed surface 1a facing upward. The adsorption platform S is configured to gradually expand the adsorption range from the center of the pull plate direction Y toward the end of the pull plate direction Y. It should be noted that Figures 6A to 6C In the figure, illustration of films such as metal films is omitted.

[0109] In the adsorption process, the glass substrate 1 placed on the adsorption platform S is placed with the securing surface 1a facing upward, and at least the central portion 1c in the width direction X is in a bowl-shaped shape along the plate pulling direction Y. Therefore, in the adsorption process, the adsorption of the glass substrate 1 can be promoted along the plate pulling direction Y with the central portion 1c of the glass substrate 1 as the starting point. In detail, initially, as Figure 6A As shown in FIG. 1 , the central portion 1 c of the glass substrate 1 is adsorbed onto the adsorption platform S. Then, as shown in FIG. Figure 6BAs shown, adsorption is sequentially advanced from the central portion 1c toward the second side 1x (i.e., the end portion in the pulling plate direction Y) as indicated by the arrow W. Then, by this advancement of adsorption, as Figure 6C shown, the entire glass substrate 1 is correctly adsorbed by the adsorption platform S without significant positional deviation. Thus, in the exposure process, the pattern of the photomask can be correctly transferred to the resist film, and therefore, the total pitch deviation of the thin film pattern formed on the guaranteed surface 1a of the glass substrate 1 can be reliably reduced.

[0110] Next, a method for manufacturing the glass substrate 1 having the above structure will be described.

[0111] As Figure 7 and Figure 8 shown, 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. Between the forming furnace 12 and the annealing furnace 14, between the annealing furnace 14 and the cooling chamber 15, and between the cooling chamber 15 and the cutting chamber 16, they are separated by partition members (e.g., the floor surface of a building) F1, F2, F3 having openings (e.g., slits) through which the glass ribbon Gr passes.

[0112] The forming furnace 12 is a region for forming the glass ribbon Gr from the molten glass Gm by the overflow down-draw method. Inside the forming furnace 12, a forming body 13 for forming the glass ribbon Gr from the molten glass Gm and edge rollers 17 for cooling both end portions in the width direction X of the glass ribbon Gr formed by the forming body 13 are arranged.

[0113] At the top of the forming body 13, a groove portion (overflow groove) 18 is formed along the width direction. A supply pipe 19 is connected to one end side of the groove portion 18. The molten glass Gm is supplied into the groove portion 18 through this supply pipe 19. The supply method of the molten glass Gm is not limited to this. For example, the molten glass Gm can be supplied from both end sides of the groove portion 18, or the molten glass Gm can be supplied from above the groove portion 18.

[0114] Both outer side surfaces 20 of the forming body 13 each include a planar vertical surface portion 21 along the vertical direction and a planar inclined surface portion 22 connected to the lower side of the vertical surface portion 21 and inclined with respect to the vertical direction. Each vertical surface portion 21 is a plane parallel to each other. Each inclined surface portion 22 is a plane inclined so as to approach each other as it goes downward. That is, the forming body 13 forms each inclined surface portion 22 so as to be wedge-shaped with a tapered front end as viewed from the side, and the corner portion where the inclined surface portions 22 intersect forms the lower end portion 13a of the forming body 13. It should be noted that the vertical surface portion 21 can be changed to an inclined surface, a curved surface, etc., or can be omitted.

[0115] The edge rollers 17 are configured as a pair of rollers that sandwich each end in the width direction of the glass ribbon Gr directly below the formed body 13. The edge rollers 17 are of the cantilever type and are always cooled inside during the forming process. Therefore, the edge rollers 17 are sometimes also referred to as cooling rollers.

[0116] The annealing furnace 14 is a region for reducing the warpage and internal strain of the glass ribbon Gr. Annealing rollers 23 are arranged inside the annealing furnace 14. The annealing rollers 23 are configured as a pair of rollers that sandwich each end in the width direction of the glass ribbon Gr. The annealing rollers 23 can be of the double-supported type arranged across the entire width direction of the glass ribbon Gr, but in the present embodiment, they are of the cantilever type. The annealing rollers 23 are arranged in multiple stages in the vertical direction.

[0117] The cooling chamber 15 is a region for cooling the glass ribbon Gr to near room temperature. Handling rollers 24 are arranged inside the cooling chamber 15. The handling rollers 24 are configured as a pair of rollers that sandwich each end in the width direction of the glass ribbon Gr. The handling rollers 24 can be of the double-supported type arranged across the entire width direction of the glass ribbon Gr, but in the present embodiment, they are of the cantilever type. The handling rollers 24 are arranged in multiple stages in the vertical direction.

[0118] Among the annealing rollers 23 and / or the handling rollers 24, there may be included rollers that do not sandwich the two ends in the width direction X of the glass ribbon Gr. That is, the opposing interval of the pair of rollers constituting the annealing rollers 23 and / or the handling rollers 24 can be set to be larger than the thickness of the two ends in the width direction X of the glass ribbon Gr, or can be set such that the glass ribbon Gr passes between the pair of rollers. It should be noted that in the present embodiment, the two ends in the width direction X of the glass ribbon Gr obtained by the manufacturing apparatus 11 include ears with a thickness larger than that of the central portion in the width direction X under the influence of shrinkage during the forming process and the like.

[0119] The cutting chamber 16 is a region for cutting the glass ribbon Gr into a specified size and obtaining the glass substrate 1 as a glass article. A cutting device (not shown) for cutting the glass ribbon Gr is arranged inside the cutting chamber 16. In the present embodiment, the cutting method of the cutting device for cutting the glass ribbon Gr is scribing and cutting, which is to break along the scribed line after scribing the glass ribbon Gr, but it is not limited thereto. The cutting method of the cutting device can also be, for example, laser cutting or laser fusing.

[0120] In the method for manufacturing the glass substrate 1 using the above-described manufacturing apparatus 11, first, in the forming furnace 12, molten glass Gm is supplied to the groove portion 18 of the formed body 13, and the molten glass Gm that has overflowed from the groove portion 18 to both sides flows down along each vertical surface portion 21 and inclined surface portion 22 and rejoins at the lower end portion 13a. Thus, a strip-shaped glass ribbon Gr is continuously formed from the molten glass Gm (forming step). Next, in the annealing furnace 14, the glass ribbon Gr is annealed (annealing step), and in the cooling chamber 15, the glass ribbon Gr is cooled to near room temperature (cooling step). Thereafter, in the cutting chamber 16, the glass ribbon Gr is cut to obtain the glass substrate 1 (cutting step). The cutting step includes a first cutting step of cutting the glass ribbon Gr in the width direction X according to a specified length to obtain the glass substrate 1, and a second cutting step of cutting and removing the ear portions at both ends in the width direction X of the glass substrate 1. The pulling direction Y of the thus-manufactured glass substrate 1 corresponds to Figure 7 and Figure 8 the up-and-down direction of the glass ribbon Gr in

[0121] Here, for example, by appropriately annealing the glass ribbon Gr using the annealing step performed by the above-described annealing furnace 14, the above-described shape quality can be obtained in the glass substrate 1 cut out from the glass ribbon Gr. Specifically, for example, as shown in Figure 9 , in the annealing furnace 14, by shifting the position of the glass ribbon Gr in the thickness direction using the upper annealing roller 23a and the lower annealing roller 23b, a glass substrate 1 having the above-described shape quality can be manufactured. When the interval between the upper annealing roller 23a and the lower annealing roller 23b in the up-and-down direction is set to P, and the distance between the upper annealing roller 23a and the lower annealing roller 23b in the thickness direction is set to Q, it is sufficient that Q / P is 0.022 or more, preferably 0.03 or more, and more preferably 0.04 or more.

[0122] The multi-stage annealing rollers 23a, 23b satisfying the above-described positional relationship are preferably provided in a region where the temperature of the glass ribbon Gr is the strain point to the softening point. Alternatively, the multi-stage annealing rollers 23a, 23b satisfying the above-described positional relationship are preferably provided in a region where the viscosity of the glass ribbon Gr is 10 14.5 to 10 7.6 dPa·s.

[0123] Thus, in the annealing furnace 14, by offsetting the position of the glass ribbon Gr in the thickness direction using the upper annealing rollers 23a and the lower annealing rollers 23b, the glass ribbon Gr assumes a bowl shape in the draw 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 acting on the glass ribbon Gr in the width direction using the annealing rollers 23a. For example, regarding the shape of the glass ribbon Gr in the width direction X, if the tension acting on the glass ribbon Gr in the width direction is increased, it approaches a flat shape, and if the tension is decreased, it bends to form a bowl shape. The tension acting on the glass ribbon Gr in the width direction can be adjusted, for example, by the temperature of the glass ribbon Gr.

[0124] It should be noted that the present invention is not limited to the structure of the above-described embodiments, nor is it limited to the above-described effects. The present invention can be variously modified without departing from the gist of the present invention.

[0125] For example, if the average value ΔH of the glass substrate 1 C-E is negative, the average value ΔV C-E can also be positive.

[0126] Examples

[0127] Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

[0128] As a first example, the present inventors conducted a comparative test for confirming the effects of the present invention. In this test, glass substrates of Examples 1 to 10 and Comparative Examples 1 to 8 were produced, and the front-back deflection difference Y1 - Y2 in the draw direction Y and the front-back deflection difference X1 - X2 in the width direction X in each example were evaluated. In addition, in each example, ΔH C-E , ΔH A-G , ΔH max -ΔH min , ΔV C-E , ΔV A-G , ΔV max -ΔV min calculated from the front-back deflection difference Y1 - Y2 and the front-back deflection difference X1 - X2 were also evaluated. Moreover, the total pitch offset and the deviation in the color of the color filter were evaluated.

[0129] In the low-alkali glass substrate for a display of the example of the present invention, the OA-11 material manufactured by Nippon Electric Glass Co., Ltd. with a strain point of 685°C, a Young's modulus of 78 GPa, and a compression (thermal shrinkage amount) of about 25 ppm after heat treatment at 500°C for 1 hour was used. Hereinafter, evaluations based on several examples were conducted.

[0130] The evaluation conditions for each example in the first example are as described below.

[0131] (1) In each example, the length of the side in the pulling direction Y of the glass substrate is 2200 mm, the length of the side in the width direction X is 2500 mm, and the thickness is 0.5 mm.

[0132] (2) The seven evaluation regions A - G of the glass substrate in each example were set by the Figure 1 scheme shown. The length of the side in the pulling direction Y of each evaluation region A - G is 500 mm, and the length of the side in the width direction X is 400 mm. The intervals L1 and L2 between the widthwise centers of adjacent evaluation regions in the width direction X are 400 mm between evaluation regions B - F, and 250 mm between evaluation regions A and B and between F and G.

[0133] (3) When measuring the front - back deflection difference Y1 - Y2, the support span M in the pulling direction Y of the specimen glass corresponding to each evaluation region A - G in each example was set to 480 mm. When measuring the front - back deflection difference X1 - X2, the support span N in the width direction X of the specimen glass corresponding to each evaluation region A - G in each example was set to 380 mm. It should be noted that in each evaluation region of each example, the specimen glass used for measuring the front - back deflection difference Y1 - Y2 and the specimen glass used for measuring the front - back deflection difference X1 - X2 were the same glass.

[0134] (4) In the glass substrate of each example, a thin - film pattern of a color filter composed of a black matrix was formed, the total pitch was measured, and the color deviation was evaluated. The measured total pitch was evaluated in four grades: excellent (◎), good (○), acceptable (Δ), and unacceptable (×). The color deviation was evaluated in three grades: good (○), acceptable (△), and unacceptable (×).

[0135] The results of the comparative tests conducted under the above conditions are shown in Tables 1 - 4. It should be noted that Table 1 shows the results of the front - back deflection difference Y1 - Y2 in the pulling direction Y of Examples 1 - 8, and Table 2 shows the results of the front - back deflection difference X1 - X2 in the width direction X of Examples 1 - 8. On the other hand, Table 3 shows the results of the front - back deflection difference Y1 - Y2 in the pulling direction Y of Comparative Examples 1 - 8, and Table 4 shows the results of the front - back deflection difference X1 - X2 in the width direction X of Comparative Examples 1 - 8.

[0136]

Table 1

[0137]

[0138]

Table 2

[0139]

[0140]

Table 3

[0141]

[0142]

Table 4

[0143]

[0144] As can also be seen from Table 1 and Table 2, in Examples 1 to 10, the average value ΔH of the front-back deflection difference Y1 - Y2 in the drawbar direction Y of the evaluation regions C to E C-E is a negative value, and the evaluations of the total pitch shift of the color filter and the color deviation are all excellent, good, or acceptable. In contrast, as can also be seen from Table 3 and Table 4, in Comparative Examples 1 to 8, the average value ΔH of the front-back deflection difference Y1 - Y2 in the drawbar direction Y of the evaluation regions C to E C-E is a positive value, and the evaluations of the total pitch shift and the color deviation are both unacceptable. Based on the above, it can also be confirmed that at least the average value ΔH of the front-back deflection difference Y1 - Y2 in the drawbar direction of the evaluation regions C to E C-E being negative is effective in reducing the total pitch shift of the thin film pattern.

[0145] In Examples 1 to 6, ΔH max -ΔH min and ΔV max -ΔV min are all 0.3 mm or less, and the evaluation of the total pitch shift is excellent. In contrast, in Examples 7 to 10, ΔH max -ΔH min and ΔV max -ΔV min either one or both increase to a value exceeding 0.3 mm, and the evaluation of the total pitch shift is reduced to good. From these, it can be confirmed that by reducing ΔH max -ΔH min and ΔV max -ΔV min the total pitch shift can be further reduced.

[0146] In Examples 1, 3, 5, and 6, ΔH A-G and ΔV A-G both become negative values, and a bowl-shaped depression is formed on the guarantee surface side in the entire drawbar direction Y and the entire width direction X, and the evaluation of the color deviation is good. In contrast, in Example 4, ΔH A-G is a positive value, a bowl-shaped shape is formed at the center in the drawbar direction Y, and bowl-shaped shapes are not formed at both ends in the drawbar direction Y. Additionally, in Example 2, ΔV A-Gis a positive value, the center in the width direction X becomes a bowl shape, but both ends in the width direction X do not become a bowl shape. As a result, in Embodiments 2 and 4, the evaluation of the color deviation is reduced to acceptable. Based on these, it can be confirmed that by setting both ΔH A-G and ΔV A-G to negative values, the total pitch shift can be further reduced.

[0147] Next, the second embodiment will be described. The evaluation conditions for each example in the second embodiment are as follows.

[0148] (1) For each example, the length of the side in the pulling direction Y of the glass substrate is 1950 mm, the length of the side in the width direction X is 2250 mm, and the thickness is 0.4 mm.

[0149] (2) Seven evaluation regions A - G in each example of the glass substrate are set to be the same as those Figure 1 shown in the scheme. The length of the side in the pulling direction Y of each evaluation region A - G is 500 mm, and the length of the side in the width direction X is 400 mm. The intervals L1 and L2 between the width direction centers of adjacent evaluation regions in the width direction X are 400 mm between evaluation regions B - F, and 125 mm between evaluation regions A and B and between F and G.

[0150] (3) When measuring the front - back deflection difference Y1 - Y2, the support span M in the pulling direction Y of the sample glass corresponding to each evaluation region A - F in each example is set to 480 mm. When measuring the front - back deflection difference X1 - X2, the support span N in the width direction X of the sample glass corresponding to each evaluation region A - G in each example is set to 380 mm. It should be noted that in each evaluation region of each example, the sample glass used to measure the front - back deflection difference Y1 - Y2 and the sample glass used to measure the front - back deflection difference X1 - X2 are the same glass.

[0151] (4) In each example, a thin film pattern of a color filter composed of a black matrix is formed on the glass substrate, the total pitch is measured, and the color deviation is evaluated. The measurement of the total pitch is evaluated in four grades: excellent (◎), good (○), acceptable (△), and unacceptable (×). The color deviation is evaluated in three grades: good (○), acceptable (△), and unacceptable (×).

[0152] The results of the comparative tests conducted under the above conditions are shown in Tables 5 - 6. It should be noted that Table 5 shows the results of the front - back deflection difference Y1 - Y2 in the pulling direction Y for Embodiments 11 - 14 and Comparative Examples 9 and 10, and Table 6 shows the results of the front - back deflection difference X1 - X2 in the width direction X for Embodiments 11 - 14 and Comparative Examples 9 and 10.

[0153]

Table 5

[0154]

[0155]

Table 6

[0156]

[0157] As can also be seen from Table 5 and Table 6, in Examples 11 to 14, the average value ΔH of the front-back deflection difference Y1 - Y2 in the draw plate direction Y of the evaluation regions C to E C-E is a negative value, and the evaluations of the total pitch shift of the color filter and the color deviation are both excellent, good, or acceptable. In contrast, in Comparative Examples 9 and 10, the average value ΔH of the front-back deflection difference Y1 - Y2 in the draw plate direction Y of the evaluation regions C to E C-E is a positive value, and the evaluations of the total pitch shift and the color deviation are both unacceptable. From the above, it can be confirmed that at least the average value ΔH of the front-back deflection difference Y1 - Y2 in the draw plate direction of the evaluation regions C to E C-E being negative is effective in reducing the total pitch shift of the thin film pattern.

[0158] In Examples 11 and 12, ΔH max -ΔH min and ΔV max -ΔV min are both 0.3 mm or less, and the evaluation of the total pitch shift is excellent. In contrast, in Examples 13 and 14, ΔV max -ΔV min increases to a value exceeding 0.3 mm, and the evaluation of the total pitch shift is reduced to good. From these, it can be confirmed that by reducing ΔH max -ΔH min and ΔV max -ΔV min the total pitch shift can be further reduced.

[0159] In Example 12, ΔH A-G and ΔV A-G are both negative values, and a bowl-shaped depression is formed on the guaranteed surface side in the entire draw plate direction Y and the entire width direction X, and the evaluation of the color deviation is good. In contrast, in Examples 11, 13, and 14, ΔH A-G is a negative value, and a bowl-shaped shape is formed at the center and both ends in the draw plate direction Y, but ΔV C-E and ΔV A-G are positive values, and the width direction X does not form a bowl-shaped shape. As a result, in Examples 11, 13, and 14, the evaluation of the color deviation is reduced to acceptable. It can be confirmed that by setting both ΔH A-G and ΔV A-G to negative values, the total pitch shift can be further reduced.

[0160] Explanation of Reference Numerals

[0161] 1: Glass substrate, 1a: Guaranteed surface, 1b: Non-guaranteed surface, 1x: Edge along the width direction, 1y: Edge along the draw plate direction, 3: Specimen glass, 3a: Guaranteed surface, 3b: Non-guaranteed surface, 3x: Edge along the width direction, 3y: Edge along the draw plate direction, 11: Manufacturing apparatus, 12: Forming furnace, 13: Formed body, 14: Annealing furnace, 15: Cooling chamber, 16: Cutting chamber, 17: Edge roll, 23: Annealing roll, 24: Conveying roll, A - G: Evaluation regions, Gm: Molten glass, Gr: Glass ribbon, S: Adsorption platform, X1, X2: Deflection in the width direction, Y1, Y2: Deflection in the draw plate direction, X: Width direction, Y: Draw plate direction.

Claims

1. A glass substrate, which is in a rectangular shape and has a first side along the pulling direction of the plate and a second side along the width direction orthogonal to the pulling direction of the plate. The length of the second side is 1500 mm or more and the thickness is 1.3 mm or less. One main surface is the guaranteed surface. The glass substrate is characterized in that When seven evaluation regions A, B, C, D, E, F, and G having the same rectangular shape are sequentially set from one end side in the width direction, the average value ΔH of the front-back deflection difference in the draw plate direction of the evaluation regions C, D, and E in the central portion is obtained by the following mathematical formula (1) C－E is negative Back - front deflection difference=(Y1 - Y2)[mm] (1) Y1: The deflection in the pulling direction of the sample glass corresponding to the evaluation area for measuring the back - front deflection difference when the guaranteed surface faces downward. Y2: The deflection in the pulling direction of the sample glass corresponding to the evaluation area for measuring the back - front deflection difference when the guaranteed surface faces upward.

2. The glass substrate according to claim 1, wherein The average value ΔH of the front-back flexure difference in the drawplate direction of the evaluation regions A, B, C, D, E, F, and G A－G is negative.

3. The glass substrate according to claim 1 or 2, wherein When the values of the front-back deflection differences in the drawplate directions of the evaluation regions A, B, C, D, E, F, and G are set as ΔH A , ΔH B , ΔH C , ΔH D , ΔH E , ΔH F , ΔH G , at least ΔH A ~ΔH G among them, ΔH C , ΔH D , ΔH E are negative respectively.

4. The glass substrate according to claim 1 or 2, wherein The maximum value ΔH of the front-back deflection difference in the draw plate direction in the evaluation regions A, B, C, D, E, F, and G max and the minimum value ΔH of the front-back deflection difference in the draw plate direction in the evaluation regions A, B, C, D, E, F, and G min The difference ΔH max -ΔH min is 0.5 mm or less.

5. The glass substrate according to claim 1 or 2, wherein The average value ΔV of the front-back deflection difference in the width direction of the evaluation regions C, D, and E in the central portion, obtained from the following mathematical formula (2) C－E is ΔV C－E ≤ 0 Back - front deflection difference=(X1 - X2)[mm] (2) X1: The deflection in the width direction of the sample glass corresponding to the evaluation area for measuring the back - front deflection difference when the guaranteed surface faces downward. X2: The deflection in the width direction of the sample glass corresponding to the evaluation area for measuring the back - front deflection difference when the guaranteed surface faces upward.

6. The glass substrate according to claim 5, wherein The average value ΔV of the front-back flexure difference in the width direction of the evaluation regions A, B, C, D, E, F, and G A－G is negative.

7. The glass substrate according to claim 5, wherein The maximum value ΔV of the front-back deflection difference in the width direction in the evaluation regions A, B, C, D, E, F, and G max and the minimum value ΔV of the front-back deflection difference in the width direction in the evaluation regions A, B, C, D, E, F, and G min The difference ΔV max -ΔV min is 0.7 mm or less.

8. The glass substrate according to claim 1 or 2, wherein The glass substrate is a low - alkali glass substrate for a display, the strain point is 670 °C or more, the Young's modulus is 77 GPa or more, and the thermal shrinkage amount when maintained at 500 °C for one hour is 40 ppm or less.

9. The glass substrate according to claim 1 or 2, 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. The glass substrate according to claim 1 or 2, wherein The length of the second side is 2200 mm or more.

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

12. The glass substrate according to claim 1 or 2, wherein The thickness is 0.5 mm or less.

13. A manufacturing method of an electronic device, comprising: a preparation process of preparing the glass substrate according to any one of claims 1 to 12; and a manufacturing process of manufacturing an electronic device using the glass substrate. The manufacturing method of the electronic device is characterized in that The manufacturing process includes an adsorption process of adsorbing the glass substrate with the guaranteed surface facing upward in a state of being placed on an adsorption platform. In the adsorption process, starting from the central portion of the glass substrate in the pulling direction of the plate, the adsorption of the glass substrate is advanced along the pulling direction of the plate.

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