JP7070197B2 - Glass substrate for TFT - Google Patents

Description

The present invention relates to a glass substrate for TFT.

Conventionally, a flat display panel such as a liquid crystal display is manufactured by facing two glass substrates having an element or structure such as a fine electrode or a partition wall formed on the surface thereof. For a glass substrate for a flat display panel, various films are uniformly applied to the surface thereof, and then exposed and developed using a photoprocess method to form elements and structures on the glass substrate. It is customary to apply the manufacturing process of a thin film transistor (TFT). As a glass substrate for that purpose, for example, in Patent Document 1, for a glass plate of 300 mm × 300 mm or more, the difference in plate thickness between the reference point and a position 20 mm apart from the reference point in the X and / or Y directions, respectively. A glass substrate having an absolute value of 3 μm or less is disclosed.

Japanese Unexamined Patent Publication No. 2009-155136

At present, it is required to form elements and structures on a glass substrate with higher accuracy and / or quickly, but it has not yet reached a sufficient area.

The present invention provides a glass substrate for a TFT capable of forming an element or a structure with higher accuracy and / or quickly.

The glass substrate for TFT of the present invention is composed of a rectangular glass plate having a first main surface and a second main surface facing the first main surface, and is viewed from the thickness direction of the glass plate. The glass plate has a first side and a second side adjacent to each other, and the length of the first side and the second side is at least 1200 mm or more, and the cross section of the glass plate in the plate thickness direction is described. In the first cross section along a straight line parallel to the first side, the plate thickness tolerance, which is the difference between the maximum value of the plate thickness of the glass plate and the minimum value of the plate thickness, is less than 6.26 μm.

According to the present invention, it is possible to provide a glass substrate for a TFT having a glass plate having a small plate thickness tolerance and a large size, which is easy to focus in, for example, in an exposure process in a TFT production line and is suitable for TFT production.

1A and 1B show an example of a first embodiment of a glass substrate for a TFT according to the present invention, FIG. 1A is a front perspective view, FIG. 1B is a sectional view taken along the line AA of FIG. The enlarged schematic diagram of part B of (b) is shown. FIG. 2 is a schematic view showing an example of a float glass manufacturing apparatus for a glass substrate for a TFT according to the present invention. FIG. 3 is a schematic view showing a convex portion generated during the manufacture of the glass substrate for TFT according to the present invention. 4A and 4B specifically show the convex portion of FIG. 3, FIG. 4A is a front perspective view of a glass plate, and FIG. 4B is an explanatory view showing an etching state of the convex portion. FIG. 5 is a schematic view showing an injector installed in a float glass manufacturing apparatus for a TFT glass substrate according to the present invention. 6A and 6B are schematic views of a beam which is an injector long in the width direction of a glass plate, FIG. 6A is an overall configuration diagram of the beam, and each of FIGS. 6B to 6D is an HF in three gas systems. It is a schematic diagram which shows the flow of a gas. FIG. 7 is a graph obtained by actually measuring and plotting the plate thickness tolerance in the first cross section between the TFT glass substrate according to the present invention and the comparative example. FIG. 8 is a graph obtained by actually measuring and plotting the plate thickness tolerances of the TFT glass substrate according to the present invention and the comparative example in all cross sections. FIG. 9 is a graph comparing the average value of the absolute values of the first derivative values of the plate thickness of the first cross section between the glass substrate for TFT according to the present invention and the comparative example. FIG. 10 is a front perspective view showing an example of a second embodiment of the glass substrate for TFT according to the present invention. FIG. 11 is a table showing the ratio of roughness at each processing temperature in the glass substrate for TFT according to the present invention. FIG. 12 is a front perspective view showing an example of a third embodiment of the glass substrate for TFT according to the present invention. FIG. 13 is a graph obtained by measuring and plotting the fluorine content in the first region and the second region at each processing temperature in the glass substrate for TFT according to the present invention. FIG. 14 is a table showing the calculation results based on FIG. FIG. 15 is a graph obtained by measuring and plotting the β-OH amount of the first main surface and the second main surface of the glass substrate for TFT according to the present invention.

Hereinafter, an example of a specific embodiment of the glass substrate for TFT according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the TFT glass substrate 1 of the present embodiment is composed of a rectangular glass plate 10 having a first main surface 11 and a second main surface 12 facing the first main surface 11. Further, a first side 13 connecting the first main surface 11 and the second main surface 12 and a second side 14 adjacent to the first side 13 are provided. In the field of view from the plate thickness direction of the glass plate 10, the first side 13 and the second side 14 are adjacent to each other. The glass substrate 1 for a TFT of the present embodiment is composed of a large glass plate 10 having a length of a first side 13 and a second side 14 of at least 1200 mm or more. The field of view of the glass plate 10 from the plate thickness direction refers to a plan view. In the present specification, the rectangle is not intended only as a strict rectangle, but a shape in which two adjacent sides intersect in a range of 10 to 170 ° or a four corners are chamfered in a curved or polygonal shape. It may have a rectangular shape. If the rectangle is an exact rectangle, the first side 13 and the second side 14 intersect perpendicularly to each other.

In recent years, from the viewpoint of improving efficiency, such a large glass plate 10 has been divided into small pieces in the future to obtain a plurality of glass substrates. In the process, in the state of the large glass plate 10, the TFT required for each glass substrate is formed while assuming the planned division line in the future. However, in the large glass plate 10, even if the glass surface is slightly tilted, there is a large difference in plate thickness between the one end surface side and the corresponding other end surface side. Further, the larger the glass plate 10, the more undulations and the like of the glass plate due to various factors in the manufacturing process are included, and the plate thickness varies from place to place in the glass plate 10. Further, it is extremely difficult to eliminate these differences and variations in plate thickness even if the glass surface is polished.

On the other hand, in the TFT forming process, it is necessary to focus on the glass surface or the like with an exposure machine, but in the case of the large glass plate 10 having the above-mentioned problems, there are the following problems. That is, the exposure machine had to frequently and finely adjust the focal point for the unevenness of the surface of the glass plate 10, and could not process it at high speed. Further, when the change of the unevenness is too steep, the focal point cannot be sufficiently adjusted on the exposure machine side, and the accuracy of TFT formation is lowered.

In Patent Document 1, there is a possibility that there is unevenness of 3 μm or more in the range of 20 mm or less, and in that case, there is a problem of a decrease in speed and a decrease in accuracy as described above. Further, for the TFT forming process in which the entire main surface of the glass plate is exposed, there is a possibility that the local regulation of the plate thickness only at the reference point and the position 20 mm away from the reference point is insufficient.

In the present embodiment, the second main surface 12 of the glass plate 10 is the semiconductor element forming surface in the glass substrate 1 for TFT, and the first main surface 11 is the glass surface on the opposite side of the semiconductor element forming surface, and the semiconductor element. At the time of formation, it is fixed on the suction stage by vacuum suction.

Further, the glass plate 10 has a first cross section 15 in the direction of the plate thickness W of the glass plate 10 along a straight line parallel to the first side 13 (see (b) in FIG. 1). When the first main surface 11 of the first cross section 15 is schematically enlarged, the first main surface 11 is a continuous surface of unevenness, and the maximum value Wmax of the plate thickness W of the glass plate 10 and the minimum value Wmin of the plate thickness W are obtained. (See (c) in FIG. 1). The plate thickness W was measured with a laser displacement meter (manufactured by KEYENCE, SI-F80). The measurement pitch was 20 mm for both the minor axis and the major axis. The plate thickness W of the glass plate 10 is, for example, 1.0 mm or less, and the TFT glass substrate 1 has a large and thin glass plate 10. The plate thickness W is, for example, 0.01 mm or more. The first cross section 15 is not a specified cross section, but can be arbitrarily selected along a straight line parallel to the first side 13. Further, in FIG. 1 (c), the second main surface 12 side is smooth for convenience, but it may have irregularities like the first main surface 11. When the first main surface 11 and the second main surface 12 had irregularities, the average height in the range of 20 μm, which is the analysis diameter of the displacement meter, was taken as the plate thickness.

The TFT glass substrate 1 of the present embodiment is preferably non-alkali glass. For non-alkali glass, SiO ₂ is 50 to 73%, Al ₂ O ₃ is 10.5 to 24%, B ₂ O ₃ is 0.1 to 12%, and MgO is 0 in the following oxide-based mass percentage display. It contains ~ 8%, CaO 0 ~ 14.5%, SrO 0 ~ 24%, BaO 0 ~ 13.5%, ZrO ₂ 0 ~ 5%, and is a combination of MgO, CaO, SrO and BaO. The amount (MgO + CaO + SrO + BaO) is preferably 8 to 29.5%.

For non-alkali glass, SiO ₂ is 58 to 66%, Al ₂ O ₃ is 15 to 22%, B ₂ O ₃ is 5 to 12%, and MgO is 0 to 8 in the following oxide-based mass percentage display. %, CaO is 0 to 9%, SrO is 3 to 12.5%, BaO is 0 to 2%, and the total amount of MgO, CaO, SrO and BaO (MgO + CaO + SrO + BaO) is 9 to 18%. Is preferable.

For non-alkali glass, SiO ₂ is 54 to 73%, Al ₂ O ₃ is 10.5 to 22.5%, and B ₂ O ₃ is 0.1 to 5. It contains 5%, MgO 0-8%, CaO 0-9%, SrO 0-16%, BaO 0-2.5%, and the total amount of MgO, CaO, SrO and BaO (MgO + CaO + SrO + BaO). Is preferably 8 to 26%.
By using non-alkali glass, the alkaline component contained in the glass plate 10 does not elute due to the change over time and adversely affect the TFT or the like formed on the glass surface. In the present specification, "non-alkali" does not mean that the alkaline component is completely contained in a strict sense, but refers to a concept that allows the degree of inclusion as an impurity. Specifically, for example, about 0.01% by mass is allowed.

FIG. 2 is a schematic view showing an example of a method for manufacturing the glass substrate 1 for TFT according to the present embodiment. In the glass substrate 1 for TFT according to the present embodiment, various raw materials constituting the glass are mixed in an appropriate amount, melted by heating, and then homogenized by defoaming or stirring, and a well-known float method or down-draw method (for example, fusion) is used. It is molded into a plate shape by a method such as) or a pressing method, and after slow cooling, it is cut to a desired size and commercialized. In this embodiment, a method for manufacturing the glass substrate 1 for TFT will be described by taking the float method as an example.

The float glass manufacturing apparatus 100 shown in FIG. 2 is a melting apparatus 110 that melts a glass raw material 2 into a molten glass 3 and a forming apparatus that forms a strip of molten glass 3 supplied from the melting apparatus 110 into a glass ribbon 4. The 120 is provided with a slow cooling device 130 for slowly cooling the glass ribbon 4 molded by the molding device 120.

The melting device 110 includes a melting tank 111 that houses the molten glass 3 and a burner 112 that forms a flame above the molten glass 3 housed in the melting tank 111. The glass raw material 2 charged into the melting tank 111 is gradually melted into the molten glass 3 by the radiant heat from the flame formed by the burner 112. The molten glass 3 is continuously supplied from the melting tank 111 to the molding apparatus 120.

The molding apparatus 120 includes a bathtub 122 that houses the molten tin 121. The molding apparatus 120 forms a strip-shaped glass ribbon 4 by flowing the molten glass 3 continuously supplied onto the molten tin 121 in a predetermined direction on the molten tin 121. The atmospheric temperature in the molding apparatus 120 becomes lower as it goes from the inlet to the outlet of the molding apparatus 120. The atmospheric temperature in the molding apparatus 120 is adjusted by a heater or the like (not shown) provided in the molding apparatus 120. The glass ribbon 4 is cooled while flowing in a predetermined direction, and is pulled up from the molten tin 121 in the downstream region of the bathtub 122. The glass ribbon 4 pulled up from the molten tin 121 is conveyed to the slow cooling device 130 by the lift-out roll 140.

The slow cooling device 130 slowly cools the glass ribbon 4 molded by the molding device 120. The slow cooling device 130 includes, for example, a slow cooling furnace (rare) 131 having a heat insulating structure, and a plurality of transport rolls 132 arranged in the slow cooling furnace 131 to transport the glass ribbon 4 in a predetermined direction. The atmospheric temperature in the slow cooling furnace 131 becomes lower as it goes from the inlet to the outlet of the slow cooling furnace 131. The atmospheric temperature in the slow cooling furnace 131 is adjusted by a plurality of heaters 133 and the like provided in the slow cooling furnace 131. Further, an injector 200 for blowing an etching gas, which will be described later, onto the glass ribbon 4 is provided in the slow cooling device 130.

The glass ribbon 4 carried out from the outlet of the slow cooling furnace 131 is cut into a predetermined size by a cutting machine and shipped as a TFT glass substrate 1 composed of a glass plate 10. If necessary, at least one of both surfaces of the TFT glass substrate 1 may be polished and washed before shipping.

In the manufacturing process of the glass plate 10 including the above-mentioned float glass manufacturing apparatus 100 mentioned as an example, the surface of the glass plate 10 may be uneven due to a habit peculiar to the manufacturing apparatus. In particular, as shown in FIG. 3, from the molding apparatus 120 to the slow cooling apparatus 130, a phenomenon may be observed in which convex portions 16 on the line are generated at a plurality of locations in the width direction of the glass plate 10. Further, as shown in FIG. 4, the convex portion 16 is often formed on a line in a direction parallel to the first side 13 of the glass plate 10. In FIGS. 3 and 4, the convex portion 16 is illustrated in parallel with the first side 13, but is not limited thereto. That is, the line shape does not have to be parallel to the first side 13, and there may be a divided or partially chipped portion in the middle, and there may be a continuous or discontinuous portion in the middle.

In order to etch and smooth the unevenness and the convex portion 16 on the surface (see (b) in FIG. 4), the uneven portion formed on the glass ribbon 4 with the etching gas in the slow cooling device 130 of the float glass manufacturing apparatus 100. It is provided with an injector 200 for spraying on the convex portion 16 and the like.

Note that FIG. 4 shows an example in which the convex portion 16 is formed only on the first main surface 11 side, but the present invention is not limited to this. That is, the convex portion may be formed only on the second main surface 12 side, or may be formed on both the first main surface 11 and the second main surface 12. If there is a convex portion 16 on the first main surface 11 side, there is a convex portion 16 on the first main surface 11 side and on the second main surface 12 side so that any convex portion can be formed. In some cases, it is preferable to provide the injector 200 on the second main surface 12 side.

If the convex portion 16 is formed on the first main surface 11, when the first main surface 11 is adsorbed and fixed in the TFT forming step, a new convex portion derived from the convex portion 16 is generated on the second main surface 12 side. Can be formed into. Therefore, it is preferable that the unevenness existing on the surface of the glass plate is extremely small regardless of whether or not the semiconductor element forming surface is formed, and even when the convex portion 16 on the first main surface 11 side is removed, the second main surface 12 is used. Elements and structures can be formed on the side with higher accuracy and / or faster.

The injector 200 will be described in detail with reference to FIG. FIG. 5 is an example of the injector 200.

The injector 200 includes a supply port 201 for blowing an etching gas such as hydrogen fluoride (HF) gas onto the glass ribbon 4, and an exhaust port 202 for exhausting the etching gas. The embodiment has exhaust ports 202 on both sides of one supply port 201, respectively.

The gas (etching gas) sprayed from the supply port 201 of the injector 200 to the surface of the glass ribbon 4 is a gas in the forward direction (arrow A direction) or the reverse direction with respect to the moving direction of the glass ribbon 4 (see arrow A). It moves through the flow path 203 indicating the flow, flows out to the exhaust port 202, and is exhausted. That is, in the double flow type, the flow path 203 from the supply port 201 to the exhaust port 202 is evenly divided in the forward direction and the reverse direction with respect to the moving direction of the glass ribbon 4.

The distance D between the bottom surface of the supply port 201 of the injector 200 and the glass ribbon 4 is preferably 50 mm or less. By setting the thickness to 50 mm or less, it is possible to suppress the diffusion of gas into the atmosphere and allow a sufficient amount of gas to reach the surface of the glass ribbon 4 with respect to the desired amount of gas. On the contrary, if the distance between the bottom surface of the supply port 201 and the glass ribbon 4 is too short, for example, when the glass ribbon 4 produced by the float method is processed online, the position of the glass ribbon 4 changes and the glass ribbon 4 is processed. And the injector 200 may come into contact with each other.

The injector 200 may be used in any mode such as double sink or single sink, and two or more injectors 200 may be arranged in series in the flow direction of the glass to treat the surface of the glass ribbon 4.

When an etching gas such as hydrogen fluoride (HF) gas is supplied to the glass ribbon 4 transported in the float glass manufacturing apparatus 100 for surface treatment, for example, the glass ribbon 4 is transported by a transport roll as shown in FIG. When flowing over the transport roll 132, it may be supplied from the side not touching the transport roll 132, or may be supplied from between adjacent transport rolls 132 on the side touching the transport roll 132.

Further, by arranging two or more conveyors in series and installing an injector 200 between adjacent conveyors, the gas may be supplied from the side touching the conveyors to treat the surface of the glass ribbon 4. Further, when the glass ribbon 4 is flowing on the conveyor, it may be supplied from the side not touching the conveyor. Further, by using a mesh material such as a mesh belt in which a part of the glass ribbon 4 is not covered, the conveyor belt may be supplied from the side in contact with the conveyor.

The distance D between the supply port 201 of the injector 200 and the glass ribbon 4 is preferably 5 to 50 mm. The distance D is more preferably 8 mm or more. The distance D is more preferably 30 mm or less, still more preferably 20 mm or less. By setting the distance D to 5 mm or more, even if the glass ribbon 4 vibrates due to an earthquake or the like, contact between the surface of the glass ribbon 4 and the injector 200 can be avoided. On the other hand, by setting the distance D to 50 mm or less, it is possible to suppress the diffusion of gas inside the apparatus and allow a sufficient amount of gas to reach the upper surface of the glass ribbon 4 with respect to the desired amount of gas.

The flow velocity (linear velocity) of the gas is preferably 20 to 300 cm / s. By setting the flow velocity (linear velocity) to 20 cm / s or more, the air flow of the gas containing HF is particularly stable, and the glass surface can be uniformly treated. The flow velocity (linear velocity) is more preferably 50 cm / s or more, still more preferably 80 cm / s or more.

Then, as shown in FIG. 2, when the manufacturing method of the glass substrate 1 for TFT of the present embodiment is carried out as an online process, the gas is slowly cooled by setting the flow velocity (linear velocity) to 300 cm / s or less. A sufficient amount of gas can reach the upper surface of the glass ribbon 4 in a state where diffusion is suppressed inside. The flow velocity (linear velocity) is more preferably 250 cm / s or less, still more preferably 200 cm / s or less.

It is desirable that the injector 200 is arranged with respect to a predetermined surface to be processed (for example, an uneven portion, a convex portion 16, etc.), and for example, as shown in FIG. 3, the convex portions 16 are generated at three positions. In this case, it is desirable that the injectors 200 (three places in total) are arranged on the convex portions 16.

Further, a long injector may be provided in the width direction of the glass plate, and the spraying portion may be appropriately adjusted according to the convex portion 16. For example, a cross-sectional view of a beam 302 for adjusting the amount of HF gas in the width direction X of the glass ribbon 4 by dividing it into three regions shown by I, II, and III is shown in FIG. 6 (a). The beam 302 is an injector long in the width direction of the glass plate, and is configured by extending the injector 200 in FIG. 5 in a direction perpendicular to the paper surface. The gas systems 311 to 313 are divided by partition walls 314 and 315, and HF gas is discharged from the gas blowing holes (supply ports) 316 and blown onto the glass. The arrow in (a) of FIG. 6 indicates the flow of HF gas. The arrow in (b) of FIG. 6 indicates the flow of HF gas in the gas system 311. The arrow in (c) of FIG. 6 indicates the flow of HF gas in the gas system 312. The arrow in (d) of FIG. 6 indicates the flow of HF gas in the gas system 313.

The configuration of the injector is not limited to the embodiments shown in FIGS. 6A to 6D. For example, a plurality of partition walls may be provided so as to be divided into three or more. The more divided into a plurality of parts, the more local gas can be sprayed, and the pinpoint spraying to the convex portion 16 becomes possible.

At that time, a convex portion detection sensor for detecting the position of the convex portion 16 and a partition wall moving device may be provided. By providing these, the partition wall can be adjusted in the width direction so that the HF gas is blown only from directly above the convex portion 16 based on the position information of the convex portion from the convex portion detection sensor. Here, the gas system may be provided as many as the number of spaces divided by the partition wall.

Further, as another embodiment, in order to prevent the HF gas from being blown to a place other than the convex portion 16 in one gas blowing space, an unnecessary gas blowing hole 316 (directly above the place other than the convex portion 16). A gas blowing hole closing device that closes the located gas blowing hole) may be provided. In this case as well, it may be determined which gas blowing hole 316 is unnecessary based on the position information of the convex portion 16 from the convex portion detection sensor, and the gas blowing hole closing device may be controlled. In this case, it is not necessary to provide a plurality of gas systems and partition walls.

Further, as another embodiment, in order to prevent the HF gas from being blown to a place other than the convex portion 16 in one gas blowing space, an unnecessary gas blowing hole 316 (directly above the portion other than the convex portion 16). A suction device for sucking the HF gas ejected from the located gas blowing hole) may be provided. In this case as well, the suction device may be controlled by determining which gas blowing hole 316 is unnecessary based on the position information of the convex portion 16 from the convex portion detection sensor. In this case, it is not necessary to provide a plurality of gas systems and partition walls.

The method for manufacturing the glass substrate 1 for TFT of the present embodiment may be carried out as an online process or an offline process. The term "online processing" as used herein refers to a case where the method of the present embodiment is applied in a slow cooling process of slowly cooling a glass ribbon 4 formed by a float method, a down draw method, or the like. On the other hand, the "offline processing" refers to a case where the method of the present embodiment is applied to the glass plate 10 that has been molded and cut to a desired size. Therefore, the glass plate 10 in the present specification includes a glass plate 10 formed and cut to a desired size, and a glass ribbon 4 formed by a float method, a down draw method, or the like.

The method for manufacturing the glass substrate 1 for TFT of the present embodiment is preferably carried out as an online process for the following reasons. With offline processing, it is necessary to increase the number of processes, while with online processing, it is not necessary to increase the number of processes, so processing is possible at low cost. Further, in the offline processing, the gas containing HF wraps around the semiconductor element forming surface which is the second main surface 12 of the glass plate 10, whereas in the online processing of the glass ribbon 4, the gas containing HF is used. It is possible to suppress wraparound.

In the float glass manufacturing apparatus 100 shown in FIG. 2, an injector 200 is installed above the glass ribbon 4 in the slow cooling apparatus 130 in order to carry out the manufacturing method of the glass substrate 1 for TFT of the present embodiment as an online process. , The injector 200 is used to supply a gas containing hydrogen fluoride (HF) to the top surface of the glass ribbon 4. Further, in FIG. 2, the injector 200 is installed in the slow cooling device 130, but if the glass surface temperature for supplying the gas containing HF is 500 to 900 ° C., the injector 200 is placed in the molding device 120. It may be installed.

In the method for manufacturing a glass substrate 1 for TFT of the present embodiment, at least one surface of the glass ribbon 4 is surface-treated by spraying a gas containing hydrogen fluoride (HF) on at least one surface thereof. Instead of hydrogen fluoride gas, a gas (gas) or a liquid containing a molecule having a fluorine atom in its structure may be used.

As the etching gas, hydrogen fluoride (HF), Freon (for example, chlorofluorocarbon (CFC), fluorocarbon (FC), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC)), halon, hydrogen fluoride (HF), fluorine. Simple (F ₂ ) Trifluoroacetic acid (CF ₃ COOH), Carbon tetrafluoride (CF ₄ ), Silicon tetrafluoride (SiF ₄ ), Phosphorus fluorinated (PF ₅ ), Phosphorus trifluoride (PF ₃ ), Boron trifluoride (BF ₃ ), nitrogen trifluoride (NF ₃ ), chlorine trifluoride (ClF ₃ ) and the like can be used, but are not limited to these gases and liquids. Among these, hydrogen fluoride (HF) gas is preferable because of its cost and well-known handling method.

FIG. 7 is a graph in which the plate thickness tolerance (μm) of the first cross section 15 is actually measured in Comparative Examples (A to C) using the TFT glass substrate 1 of the present embodiment as an example. In the embodiment, the position information of the convex portion is obtained from a glass ribbon having a width of 3500 mm, and HF gas is sprayed on the position of the convex portion to remove the convex portion. Here, the gas flow rate was 0.5 m / SEC, the glass temperature was 625 to 575 ° C., the gas concentration was 20% HF, 80% N2, and the treatment time was about 10 sec. Since the removal amount has a linear relationship with the HF concentration in the gas and the processing time, the removal amount can also be adjusted by adjusting the two parameters on the left. Then, the glass ribbon was cut to obtain a glass plate having a size of 1200 mm × 1200 mm, which was used as an example. Comparative Examples A to C are large-sized glass plates for TFTs having a size of 1200 mm × 1200 mm or more, and can be obtained through a general distribution route.

In FIG. 7, each plot measures the plate thickness at a pitch of 20 mm in the first cross section 15, and shows the tolerance obtained based on the data. The number of the plurality of plots in the same sample indicates the number of N (the number of measurements), which are values obtained from different first cross sections 15.

From this graph, in the TFT glass substrate 1 of the present embodiment, the maximum value Wmax of the plate thickness W and the minimum value of the plate thickness W of the glass plate 10 in the first cross section 15 along the straight line parallel to the first side 13. It can be understood that the plate thickness tolerance, which is the difference in Wmin, is less than 6.26 μm. Further, it is preferably 6.0 μm, 5.8 μm, 5.5 μm, 5.3 μm, 5.0 μm or less. The lower limit is not limited, but is, for example, 1.0 μm or more.

As described above, in the exposure process in the TFT production line, a glass plate 10 having a small plate thickness tolerance is required so that the exposure machine can be easily focused. The TFT glass substrate 1 of the present embodiment is a glass plate. The length of the first side 13 and the second side 14 of 10 is at least 1200 mm or more, and there is no glass plate 10 having such a large size and a plate thickness tolerance of less than 6.26 μm. The form of the glass substrate 1 for TFT can form an element or a structure with higher accuracy and / or quickly.

Further, the fact that the plate thickness tolerance in the first cross section 15 is extremely small is an effect that the convex portion 16 and the like generated by the habit peculiar to the glass plate manufacturing apparatus are smoothed by the etching gas, and the plate thickness W changes. It means small.

FIG. 8 shows, using the TFT glass substrate 1 of the present embodiment as an example, actually measuring the plate thickness tolerance (μm) of all cross sections with respect to the entire surface of the glass plate 10 in Comparative Examples (A to C). It is a plotted graph.

In FIG. 8, each plot measures the plate thickness at a plurality of points at a pitch of 20 mm in the cross section of the arbitrarily extracted glass plate in the plate thickness direction, and shows the tolerance obtained based on the data. It should be noted that the number of the plurality of plots in the same sample indicates the number of N, and each is a value obtained from another randomly selected cross section.

From this graph, it can be understood that the TFT glass substrate 1 of the present embodiment has a plate thickness tolerance of less than 7.12 μm in all cross sections of the glass plate in the plate thickness direction. And, in every cross section, the effect of reducing the plate thickness tolerance can be seen. Therefore, in the present embodiment, the glass substrate 1 for TFT, which has a large glass plate 10 having a small plate thickness tolerance in every cross section and can form elements and structures with higher accuracy and / or quickly during TFT manufacturing, is provided. Can be provided.

Further, the plate thickness tolerance is preferably 7.0 μm or less, more preferably 6.5 μm or less, still more preferably 6.0 μm or less. The lower limit is not limited, but is, for example, 1.0 μm or more.

FIG. 9 shows the average value of the absolute values of the first derivative of the plate thickness W of the first cross section 15 of the glass plate 10 in Comparative Examples (A to C), using the TFT glass substrate 1 of the present embodiment as an example. It is a graph comparing.

In FIG. 9, each plot is obtained by measuring the plate thickness at a plurality of points at a pitch of 20 mm in the first cross section 15 and obtaining the data based on the data. That is, the first derivative value indicates the slope of the change in plate thickness between each pitch. The number of the plurality of plots in the same sample indicates the number of N, which is a value obtained from different first cross sections 15.

From this graph, it can be understood that the glass substrate 1 for TFT of the present embodiment has an average value of the absolute values of the first derivative values of the plate thickness W of less than 1.72E-02 in the first cross section 15. The absolute value of the first derivative value of the plate thickness W indicates the degree of change (inclination) of the plate thickness W along the first cross section 15, and the smaller the average value of the absolute values over the first cross section 15, the smaller the change. (Small inclination), that is, it is smooth with few irregularities existing on the glass surface. If the average value of the absolute values of the first derivative of the plate thickness W is 1.72E-02 or more, the change in the unevenness of the glass plate surface is too steep, and it takes a lot of time to focus the exposure machine. Moreover, since the focus cannot be adjusted sufficiently, the accuracy of TFT formation tends to decrease. Therefore, according to the present embodiment, it is possible to provide a TFT glass substrate 1 capable of forming an element or a structure with higher accuracy and / or quickly at the time of manufacturing a TFT.

The average value of the absolute values of the first derivative of the plate thickness W is preferably 1.7E-02 or less, more preferably 1.65E-02 or less, and further preferably 1.6E-02 or less. The lower limit is not limited, but is, for example, 5.0E-03 or higher.

In the TFT glass substrate 1 of the present embodiment, the standard deviation of the absolute value of the first derivative of the plate thickness W is 1.5E-03 or less in the first cross section 15. The standard deviation of the absolute value of the first derivative value of the plate thickness W indicates the degree of change (inclination) of the plate thickness W along the first cross section 15. The smaller the standard deviation of the absolute value over the first cross section 15, the smaller the change (smaller the slope), the smaller the unevenness, and the smoother the surface.

The standard deviation of the absolute value of the first derivative of the plate thickness W is preferably 1.4E-03 or less, more preferably 1.3E-03 or less. The lower limit is not particularly limited, but is, for example, 1.0E-04 or higher.

In the TFT glass substrate 1 of the present embodiment, the maximum value of the absolute value of the second derivative of the plate thickness W is 6.0E-03 or less in the first cross section 15. It is preferably 5.8E-03 or less, and more preferably 5.5E-03 or less. The lower limit is not particularly limited, but is, for example, 1.0E-03 or higher. The fact that the maximum absolute value of the second derivative of the plate thickness W is small indicates that the inflection point of the plate thickness is blunted. That is, it means that a surface smoothed by the spraying effect of the etching gas is formed. Therefore, it becomes easy to focus particularly on a plurality of divided exposure machines. Therefore, according to the present embodiment, it is possible to provide a TFT glass substrate 1 capable of forming an element or a structure with higher accuracy and / or quickly at the time of manufacturing a TFT.

Further, in the TFT glass substrate 1 of the present embodiment, the standard deviation of the absolute value of the second derivative of the plate thickness W is 1.5E-04 or less in the first cross section 15. It is preferably 1.4E-04 or less, more preferably 1.3E-04 or less, and even more preferably 1.2E-04 or less. The lower limit is not particularly limited, but is, for example, 5.0E-06 or more. The fact that the standard deviation of the absolute value of the second derivative of the plate thickness W is extremely small means that there is no particularly large protrusion, the change in the plate thickness W of the glass plate 10 is small, and the surface smoothed by the effect of spraying the etching gas. Means that is formed.

In the first cross section 15, the standard deviation of the absolute value of the first derivative value of the plate thickness W, the maximum value of the absolute value of the second derivative value, and the standard deviation of the absolute value of the second derivative value are extremely small, that is, the glass plate 10 It means that the entire surface of is smoothed. By smoothing the entire surface of the glass plate 10, for example, it becomes easy to focus in an exposure process in a TFT production line, and it is possible to provide a large glass substrate 1 for TFT having excellent productivity and quality.

FIG. 10 is a front perspective view showing a second embodiment of the TFT glass substrate 1 of the present embodiment. A second embodiment will be described with reference to FIG.

In the TFT glass substrate 1 of the second embodiment, the roughened area 20 and the non-roughened area 21 are formed on the first main surface 11 of the glass plate 10 with a predetermined width. The roughened region 20 is a region to which an etching gas having a width L parallel to the second side 14 is sprayed, and may be, for example, a region where the convex portion 16 is smoothed. Further, the non-roughened region 21 is a region in which the etching gas is not sprayed. The roughened region 20 does not necessarily have to be accompanied by the removal of the convex portion 16. For example, by adjusting the amount of the etching gas to be sprayed and the glass temperature, the surface of the glass plate can be roughened with almost no decrease in the plate thickness. The glass plate 10 does not necessarily have to be smoothed.

When manufacturing a TFT, the first main surface 11 of the glass plate 10 is adsorbed and fixed, but since static electricity tends to accumulate on the first main surface 11, the glass plate 10 sticks when the adsorption fixing is released, and the glass plate 10 breaks. There's a problem. Further, there is a problem that the formed TFT element causes a malfunction due to the static electricity accumulated in the glass plate 10. To solve these problems, it is possible to form a roughened region 20 on the first main surface 11 to partially form a region with a rough surface roughness, making it difficult for static electricity to accumulate, and preventing static electricity. ..

Further, in the roughened surface region 20 sprayed with the etching gas, for example, when the convex portion 16 or the like is smoothed by etching, the plate thickness tolerance in the plate thickness W direction is extremely reduced and a predetermined roughness Ra is imparted. can do. This makes it possible to provide a glass substrate 1 for a TFT having a large glass plate 10 capable of forming elements and structures with higher accuracy and / or quickly in TFT manufacturing and preventing charging. Roughness Ra was measured using an Atomic Force Microscope (Manufactured by Bruker, Dimension Icon) under the conditions of Scan Assist mode, scan size: 5 μm × 5 μm, and scan rate: 0.977 Hz. Then, after performing a second-order tilt correction, the arithmetic mean roughness (Ra) within the above range was calculated.

In the second embodiment, the roughened region 20 is formed in a line shape having a predetermined width L in a direction parallel to the first side 13 of the glass plate 10. Further, the roughened surface region 20 can be arbitrarily increased, and a plurality of roughened regions 20 may be formed in a line shape in a direction parallel to the first side 13.

FIG. 11 shows the ratio of the roughness Ra ₁ of the roughened region 20 and the roughness Ra ₂ of the non-roughened region 21 to the roughness Ra (ratio of Ra ₁ and Ra ₂ ) at each treatment temperature (° C.). It is a table showing. The processing temperature (° C.) is the atmospheric temperature around the glass when the etching gas is sprayed in the manufacturing process. Roughness Ra ₁ and Ra ₂ are average values obtained by measuring 10 points each of the roughened region and the non-roughened region.

From this table, it can be understood that in the TFT glass substrate 1 of the present embodiment, the ratio of the roughness Ra between the roughened region 20 and the non-roughened region 21 is larger than 1. It is preferably 3 or more, more preferably 10 or more, and even more preferably 20 or more. The upper limit is not particularly limited, but is, for example, 100 or less. When the ratio of the roughness Ra is set to the above range, it is possible to prevent static electricity from being accumulated in the roughened surface region and the entire glass plate, thereby preventing static electricity.

Further, the arithmetic average roughness Ra ₁ of the roughened region 20 of the TFT glass substrate 1 of the present embodiment is Ra ₁ > 0.5 nm, and the arithmetic average roughness Ra ₂ of the non-roughened region 21 is It can be understood that Ra ₂ ≤ 0.5 nm. Ra ₁ is preferably 1.0 nm or more, more preferably 3.0 nm or more, still more preferably 5.0 nm or more. The upper limit is not particularly limited, but is, for example, 50 nm or less, preferably 30 nm or less, and more preferably 20 nm or less. The lower limit of Ra ₂ is not particularly limited, but is, for example, 0.2 nm or more. When the arithmetic average roughness Ra ₁ of the roughened region 20 and the arithmetic average roughness Ra ₂ of the non-roughened region 21 are set to the above ranges, static electricity is less likely to be accumulated in the roughened region and eventually the entire glass plate. It can prevent static electricity and can form elements and structures with higher accuracy and / or faster in TFT manufacturing.

Further, in the TFT glass substrate 1 of the present embodiment, the area of the roughened region 20 is smaller than the area of the non-roughened region 21, and the area of the roughened region 20 and the non-roughened region 21 The ratio to the area is 3 or more and 300 or less. By spraying the etching gas only on the necessary portion, efficient surface treatment of the glass plate 10 becomes possible, charging can be prevented, and elements and structures can be formed with higher accuracy and / or quickly in TFT manufacturing.

For example, when gas is blown onto a glass plate 10 having a first side 13 of 1200 mm with a width of 400 mm, the ratio of the area of the roughened region 20 to the area of the non-roughened region 21 is preferably 5, 10 or more. , More preferably 20 or more. Further, for example, when gas is blown onto a glass plate 10 having a first side 13 of 3000 mm in a width of 10 mm, the ratio is preferably 280 or less, more preferably 250 or less, still more preferably 230 or less. By applying the treatment only to the necessary parts, it is possible to efficiently treat the surface of the glass plate 10. Further, when the convex portion 16 is removed, the glass plate can be smoothed.

The roughened region 20 has a width L in a direction parallel to the second side 14 of 10 mm or more and 1000 mm or less. The width L is preferably 20 mm or more, more preferably 30 mm or more, still more preferably 50 mm or more, and preferably 900 mm or less, more preferably 800 mm or less, still more preferably 700 mm or less. By applying the treatment only to the necessary parts, it is possible to efficiently treat the surface of the glass plate 10. Further, when the convex portion 16 is removed, the glass plate can be smoothed. When there are a plurality of roughened regions 20, the width L does not refer to the total of all the roughened regions 20, but to the width of one roughened region 20.

FIG. 12 is a front perspective view showing a third embodiment of the TFT glass substrate 1 of the present embodiment. A third embodiment will be described with reference to FIG.

In the TFT glass substrate 1 of the third embodiment, the first region 30 and the second region 31 are formed on the first main surface 11 of the glass plate 10 with a predetermined width. The first region 30 is a region to which a gas containing fluorine (HF or the like), which is an etching gas having a width L parallel to the second side 14, is sprayed. For example, the convex portion 16 is smoothed to reduce the plate thickness tolerance. It is also a region having a predetermined roughness Ra. Further, the second region 31 is a region in which a gas containing fluorine is not sprayed. The first region 30 does not necessarily have to be accompanied by the removal of the convex portion 16. For example, by adjusting the amount of HF gas to be sprayed and the glass temperature, fluorine can be imparted to the surface of the glass plate with almost no decrease in the plate thickness. The glass plate 10 does not necessarily have to be smoothed.

In the third embodiment, the first region 30 sprayed with the fluorine-containing gas is formed in a line shape in a direction parallel to the first side 13 of the glass plate 10. Further, the first region 30 can be arbitrarily increased, and a plurality of first regions 30 may be formed in a line shape in a direction parallel to the first side 13.

FIG. 13 is a graph obtained by measuring and plotting the fluorine content (wt%) between the first region 30 and the second region 31 at each treatment temperature (° C.). The horizontal axis indicates the sample number, and No. 1 and No. 12 is the second region 31, and the others (Nos. 2 to 11) are the first region 30. The spacing between each sample is 25 mm. The processing temperature (° C.) is the atmospheric temperature around the glass when a gas containing fluorine is blown in the manufacturing process. The fluorine content was measured using X-ray Fluorescence (ZSX Primus II, manufactured by Rigaku). The analysis diameter was φ20 mm, and the intensity of FKα rays on the glass surface was measured. Then, the F concentration of the sample was calculated based on the calibration curve taken with the glass having the same composition as which the F concentration is known.

FIG. 14 is a table showing the values calculated based on the measured values of FIG. The fluorine content F (wt%) of the first region 30 and the second region 31 is the average value of each sample at each treatment temperature, and the F concentration ratio is the F value of the first region 30 and the F value of the second region 31. It is a value divided by a value, and the F slope (wt% / mm) is the sample No. 1 and No. It is a value calculated by the slope with 2 (value of No. 2 / value of No. 1).

From the graph of FIG. 13 and the table of FIG. 14, it can be understood that the ratio of the fluorine content (wt%) between the first region 30 and the second region 31 is larger than 1. The ratio is preferably 3 or more, more preferably 5 or more, and even more preferably 8 or more. The upper limit is not particularly limited, but is, for example, 40 or less, preferably 35 or less, more preferably 30 or less, and further preferably 25 or less. When the glass composition originally has no fluorine, the fluorine content of the second region 31 is 0, and the ratio value becomes infinite.

By spraying a gas containing fluorine on the first region 30, water and oil repellency can be imparted to the surface of the first region 30. That is, the region can be set so that the element for the TFT is easily peeled off. For example, when the first region 30 is formed in a line shape on the second main surface 12 which is the TFT forming surface and coincides with the planned division line in the future, an element is erroneously formed in the region of the planned division line. Even if it does, it can be easily peeled off.

When, for example, the convex portion 16 and the like are smoothed with an etching gas containing fluorine, fluorine can be applied to the first region while extremely reducing the plate thickness tolerance in the plate thickness W direction, and the element or structure can be applied in TFT manufacturing. It is possible to provide a glass substrate 1 for a TFT having a large glass plate 10 which can be formed with higher accuracy and / or quickly and can impart water and oil repellency to a first region. Further, since the region roughened by fluorine can be formed, it is possible to provide a glass substrate 1 for a TFT that makes it difficult for static electricity to accumulate at the time of manufacturing a TFT and prevents static electricity.

Further, from the graph of FIG. 13 and the table of FIG. 14, the fluorine content F1 in the first region 30 is 0.5 wt% ≦ F1 ≦ 5 wt%, and the fluorine content F2 in the second region is 0 ≦. It can be understood that F2 ≦ 0.15 wt%. The lower limit of F1 is preferably 0.8 wt% or more, more preferably 1.0 wt% or more, and the upper limit of F1 is preferably 4.0 wt% or less, more preferably 3.0 wt% or less.

By setting the fluorine content F of the first region 30 and the second region 31 to the above range, it is possible to adjust the water repellency and oil repellency. Further, for example, when the convex portion 16 or the like is smoothed or roughened, it is possible to provide a glass plate 10 having a small plate thickness tolerance so that it can be easily focused in an exposure process in a TFT production line, making it difficult for static electricity to accumulate. , A glass substrate 1 for a TFT that prevents static electricity can be provided.

In the TFT glass substrate 1 of the present embodiment, the area of the first region 30 is smaller than the area of the second region 31, and the ratio of the area of the first region 30 to the area of the second region 31 is 3 or more and 300 or less. By spraying a gas containing fluorine only on a necessary portion, efficient surface treatment of the glass plate 10 becomes possible. Further, when the convex portion 16 is removed, the glass plate 10 can be smoothed.

Further, from the table of FIG. 14, in the first region 30 of the TFT glass substrate 1 of the present embodiment, the inclination of the fluorine content F in the direction parallel to the second side 14 is 0.001 wt% / mm or more. It can be understood that it is 0.15 wt% / mm or less. The content is preferably 0.13 wt% / mm or less, more preferably 0.12 wt% / mm or less, and further preferably 0.10 wt% / mm or less. By spraying a gas containing fluorine only on a necessary portion, efficient surface treatment of the glass plate 10 becomes possible. Further, when the convex portion 16 is removed, the glass plate can be smoothed.

It is desirable that the glass plate 10 of the TFT glass substrate 1 of the present embodiment has no polishing scratches on at least one of the first main surface 11 and the second main surface 12. More preferably, it is desirable that none of them has polishing scratches. The presence or absence of polishing scratches can be determined by surface observation with an AFM (Atomic Force Microscope). In the present specification, when one or more scratches having a length of 5 μm or more are present in the 100 μm × 5 μm region, it is referred to as “having a polishing scratch” on the surface, and vice versa. It is called a state. By having no polishing scratches on the first main surface 11 and the second main surface 12, elements and structures can be formed with higher accuracy and / or quickly in TFT manufacturing. In addition, the surface strength of the glass plate 10 can be increased.

FIG. 15 is a graph in which the β-OH amount of the first main surface 11 and the second main surface 12 in the present embodiment is measured.

From the graph of FIG. 15, the glass plate 10 of the glass substrate 1 for TFT of the present embodiment is bulk on both the first main surface 11 not in contact with the molten tin and the second main surface 12 in contact with the molten tin. It can be understood that the layer having a water content of 80% or less with respect to the water content (center position in the plate thickness W direction) has 10 μm or more.

If at least one of the first main surface 11 and the second main surface 12 has a layer having a water content of 80% or less with respect to the water content of the bulk of 10 μm or more, the glass plate is formed. It can be understood that the glass plate 10 is manufactured by the float method. The float method is an excellent method for obtaining a glass plate having a larger area, and it is easy to obtain a glass plate having a size of 1200 mm × 1200 mm or more. The size of the glass plate is preferably 1500 mm × 1500 mm or more, more preferably 2000 mm × 2000 mm or more, and further preferably 2500 mm × 2500 mm or more. The length of at least one side is 1200 mm to 7000 mm. A glass substrate on which a plurality of TFTs are formed can be taken out from one glass plate. The β-OH value, which is the amount of water, is measured by the transmittance by an infrared spectrophotometer or by secondary ion mass spectrometry (SIMS).

The present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, and the like. In addition, the material, shape, size, numerical value, form, number, arrangement location, etc. of each component in the above-described embodiment are arbitrary as long as the present invention can be achieved, and are not limited.

Further, the highly flat glass substrate is not limited to the glass substrate for TFT, and is required in various fields. For example, when a resin pattern is formed on the surface of glass by imprinting, the desired pattern may not be obtained because the mold is not properly pressed at the portion corresponding to the recessed region of the swell of the glass. In this case, a higher flat glass is desirable because the pressing force of the mold is uniformly transmitted to the glass surface. For example, the size of the glass used for imprinting is, in the case of a rectangular shape, at least one side having a length of 50 mm to 7000 mm.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2017-155468 filed on August 10, 2017, the contents of which are incorporated herein by reference.

The glass substrate for TFT of the present invention is suitably used in a field where a large glass plate having a small plate thickness tolerance is required in order to improve productivity and prevent static electricity in a TFT production line.

1 Glass substrate for TFT 10 Glass plate 11 1st main surface 12 2nd main surface 13 1st side 14 2nd side 15 1st cross section 16 Convex part 20 Roughened area 21 Non-roughened area 30 1st area 31st 2 areas 100 Float glass manufacturing equipment 200 Injectors

Claims (21)

It is composed of a rectangular glass plate having a first main surface and a second main surface facing the first main surface.
In the field of view from the plate thickness direction of the glass plate, it has a first side and a second side adjacent to each other.
The length of the first side and the second side is at least 1200 mm or more.
Of the cross sections in the plate thickness direction of the glass plate, the plate thickness tolerance which is the difference between the maximum value and the minimum value of the plate thickness of the glass plate in the first cross section along a straight line parallel to the first side. Is less than 6.26 μm ,
The first main surface has a roughened area and a non-roughened area.
A glass substrate for a TFT in which the ratio of the roughness of the roughened region to the non-roughened region is larger than 1 . The arithmetic mean roughness Ra ₁ of the roughened region is Ra ₁ > 0.5 nm, and the arithmetic mean roughness Ra ₂ of the non-roughened region is Ra ₂ ≤ 0.5 nm, according to claim 1 . Glass substrate for TFT. The area of the roughened area is smaller than the area of the non-roughened area.
The glass substrate for TFT according to claim 1 or 2 , wherein the ratio of the area of the roughened region to the area of the non-roughened region is 3 or more and 300 or less. The TFT glass substrate according to any one of claims 1 to 3 , wherein the roughened region is formed in a line shape in a direction parallel to the first side. The TFT glass substrate according to any one of claims 1 to 4 , wherein a plurality of the roughened regions are formed in a line in a direction parallel to the first side. The glass substrate for TFT according to claim 4 or 5 , wherein the roughened region has a width of 10 mm or more and 1000 mm or less in a direction parallel to the second side. It is composed of a rectangular glass plate having a first main surface and a second main surface facing the first main surface.
In the field of view from the plate thickness direction of the glass plate, it has a first side and a second side adjacent to each other.
The length of the first side and the second side is at least 1200 mm or more.
Of the cross sections in the plate thickness direction of the glass plate, the plate thickness tolerance which is the difference between the maximum value and the minimum value of the plate thickness of the glass plate in the first cross section along a straight line parallel to the first side. Is less than 6.26 μm,
The first main surface has a first region and a second region.
A glass substrate for TFT in which the ratio of the fluorine content between the first region and the second region is larger than 1. The seventh aspect of the present invention, wherein the fluorine content F1 in the first region is 0.5 wt% ≤ F1 ≤ 5 wt%, and the fluorine content F2 in the second region is 0 ≤ F2 ≤ 0.15 wt%. Glass substrate for TFT. The area of the first region is smaller than the area of the second region.
The glass substrate for a TFT according to claim 7 or 8 , wherein the ratio of the area of the first region to the area of the second region is 3 or more and 300 or less. The TFT glass substrate according to any one of claims 7 to 9 , wherein the first region is formed in a line shape in a direction parallel to the first side. The TFT glass substrate according to any one of claims 7 to 10 , wherein the first region is formed in a plurality of lines in a direction parallel to the first side. The glass for TFT according to claim 10 or 11 , wherein in the first region, the inclination of the fluorine content in the direction parallel to the second side is 0.001 wt% / mm or more and 0.15 wt% / mm or less. substrate. It is composed of a rectangular glass plate having a first main surface and a second main surface facing the first main surface.
In the field of view from the plate thickness direction of the glass plate, it has a first side and a second side adjacent to each other.
The length of the first side and the second side is at least 1200 mm or more.
Of the cross sections in the plate thickness direction of the glass plate, the plate thickness tolerance which is the difference between the maximum value and the minimum value of the plate thickness of the glass plate in the first cross section along a straight line parallel to the first side. Is less than 6.26 μm,
The glass plate is a glass for TFT having a layer having a water content of 80% or less with respect to the water content of the bulk of 10 μm or more on at least one of the first main surface and the second main surface. substrate. The TFT glass substrate according to any one of claims 1 to 13 , wherein the plate thickness tolerance is less than 7.12 μm in all cross sections of the glass plate in the plate thickness direction. The glass substrate for a TFT according to any one of claims 1 to 14 , wherein in the first cross section, the average value of the absolute values of the first derivative values of the plate thickness is less than 1.72E-02. The glass substrate for a TFT according to any one of claims 1 to 14 , wherein in the first cross section, the standard deviation of the absolute value of the first derivative of the plate thickness is 1.5E-03 or less. The glass substrate for a TFT according to any one of claims 1 to 16 , wherein in the first cross section, the maximum value of the absolute value of the second derivative of the plate thickness is 6.0E-03 or less. The glass substrate for a TFT according to any one of claims 1 to 17 , wherein in the first cross section, the standard deviation of the absolute value of the second derivative of the plate thickness is 1.5E-04 or less. The TFT glass substrate according to any one of claims 1 to 18, wherein the glass composition of the glass plate is non-alkali glass. The TFT glass substrate according to any one of claims 1 to 19, wherein the glass plate has no polishing scratches on at least one of the first main surface and the second main surface. The TFT glass substrate according to any one of claims 1 to 20, wherein the glass plate has a thickness of 1.0 mm or less.

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