JP2017069466A - Manufacturing method for glass substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for glass substrate including a surface treatment step capable of performing standardized production, while maintaining the quality of roughened surface, by controlling the etching rate optimally according to the tact time of the previous step and determining transportation speed of continuous treatment, in the surface treatment step for roughening the surface of the glass substrate by continuous treatment, and to provide a manufacturing device thereof.SOLUTION: In a manufacturing method of a glass substrate for display including a surface treatment step of roughening the first face, out of the principal face of a glass substrate 100, transportation speed of surface treatment is determined by controlling the etching rate by using an etching liquid, containing 10 mass% or less of hydrofluoric acid and 0.3 mass% or more of phosphoric acid, according to the tact time of the previous step, in the surface treatment process.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for manufacturing a glass substrate including a surface treatment step of roughening one of the main surfaces of a thin glass plate, and a manufacturing apparatus therefor.

  In the manufacture of a flat panel display using a liquid crystal display panel, a plasma display panel, an organic EL display panel or the like used as a display panel, a finer thin film pattern is formed on a thin glass substrate.

  The display panel used in these flat panel displays is manufactured through a processing process such as conveyance, film formation, photolithography, etching, doping, or wiring after putting a glass substrate into the production line. In each processing step, the panel including the glass substrate is placed in an environment in which it is easily charged due to various factors. For example, when putting a glass substrate into a production line, the interleaving paper is peeled and removed from a plurality of glass substrates stacked with the interleaving paper interposed therebetween, and the glass substrates are taken out one by one. At this time, the glass substrate is easily charged when the interleaf is removed. In addition, when a semiconductor manufacturing apparatus is used for film formation or the like, film formation is performed by placing a glass substrate on a mounting table. At this time, the glass substrate is likely to be charged by airflow, contact charging, or peeling charging.

  Such charging causes various problems. For example, when a TFT (Thin Film Transistor) and a wiring pattern are formed on a glass substrate, foreign matters such as dust and dust adhere to the glass substrate and the wiring pattern due to charging, and the wiring pattern is lost or peeled off or accumulated. In other words, the TFT is destroyed by the discharge of the charges. In addition, the glass substrate may stick to the mounting table due to electrification, and the glass substrate may break when it is peeled off from the mounting table. Therefore, it is preferable that the glass substrate is not charged as much as possible.

  In particular, the surface of the thin glass produced by the fusion method or the downdraw method is much smoother than the thin glass produced by the float method, and therefore, charging problems are likely to occur. For this reason, it is preferable to perform some treatment for preventing charging on the main surface of the thin glass substrate obtained by the fusion method or the downdraw method. As a general method, one of the main surfaces of the thin glass substrate is roughened by a chemical method, and charging of the thin glass substrate can be prevented by appropriate roughening. In addition, a method is known in which a charged glass substrate is neutralized using an ionizer (Patent Document 1). There is also known an exposure apparatus that reduces the amount of electrostatic charge on a processing substrate generated in a process of placing, attaching, and removing a processing substrate on which a photosensitive layer or the like is formed on a stage (Patent Document 2).

JP 2009-64950 A JP 2007-322630 A

  In a thin glass substrate for flat panel displays, the main surface of the main surface on which the TFT and wiring pattern are not formed (hereinafter referred to as the first surface) is roughened by chemical treatment or the like to prevent charging. To do. The main surface (hereinafter referred to as the second surface) on which the TFT and the wiring pattern are formed is not treated, and dirt and foreign matter must be removed.

  According to the surface treatment method using an etchant, while it is possible to continuously roughen a plurality of glass substrates, it is not easy to increase the treatment speed while keeping the surface roughness within a certain range. . This is because the etching rate of the etchant decreases as the continuous process proceeds.

  Conventionally, when continuous processing is performed using an etching solution, the etching solution is completely replaced when the performance of the etching solution is reduced to a certain level without controlling the etching rate. Under such circumstances, if the tact time fluctuates due to production scale fluctuations, the surface treatment process will respond by providing a buffer (intermediate inventory) to cover production delays. It was very difficult to achieve leveling together.

  If the etching rate can be kept constant for a longer period in the continuous treatment, the continuous treatment can be continued without reducing the transfer speed of the surface treatment step. Furthermore, if the etching rate can be maintained at a constant level, leveled production is possible, and synchronization is made in accordance with the tact time of the previous process, eliminating the need for extra buffers (intermediate inventory). I'll do it.

  Therefore, in the surface treatment process for roughening the glass substrate by continuous processing, the present invention optimally controls the etching rate according to the tact time of the previous process, and determines the conveyance speed of continuous processing. Provided are a glass substrate manufacturing method and a manufacturing apparatus thereof including a surface treatment process capable of performing leveled production while maintaining the quality of a roughened shape.

One aspect of the present invention is a method for manufacturing a glass substrate for a display, including a surface treatment step of roughening the surface by attaching an etchant to the first surface of the main surface of the glass substrate,
In the surface treatment step, the etching rate is controlled using an etching solution containing 10% by mass or less hydrofluoric acid and 0.3% by mass or more phosphoric acid in accordance with the tact time of the previous step, and the surface treatment transport speed. To decide.

  The etching solution is preferably set so that the rate of decrease in the etching rate (under the condition of processing 100 sheets at 25 ° C.) is 5% to 30%.

In the surface treatment step, the etchant is preliminarily adjusted and stored in an etchant tank, and circulates between the etchant tank and the roughening etching tank.
Further, the amount of the etching solution [liquid amount A] stored in the etching solution tank is larger than the amount of the etching solution [liquid amount B] maintained in the etching tank. It is preferable that it is stored and circulated at twice or more.

  The arithmetic average roughness Ra of the first surface after the surface treatment step is preferably 0.40 nm or more.

  The etching solution preferably contains at least 0.3 to 10% by mass of hydrofluoric acid, 0.3 to 10% by mass of phosphoric acid, and 0.3 to 15% by mass of hydrochloric acid.

  In the surface treatment step, the first surface is preferably etched at an etching rate at 25 ° C. of 0.1 μm / min or more.

  According to the glass substrate manufacturing method and the glass substrate manufacturing apparatus described above, the etching rate is optimized in accordance with the tact time of the previous process to continuously roughen the first surface of the main surface of the glass substrate. A glass substrate manufacturing method including a surface treatment step and a manufacturing apparatus thereof including a surface treatment process capable of performing leveled production while maintaining the quality of the roughened shape by controlling the conveyance speed of continuous processing. provide. According to the manufacturing method and the glass substrate manufacturing apparatus of the present invention, since the etching rate can be maintained for a long time while being high, continuous processing for a long time is realized.

It is a flowchart which shows the outline | summary of an example of the manufacturing process of the glass substrate of this embodiment. It is a schematic diagram explaining an example of the glass substrate surface treatment apparatus used at the surface treatment process of this embodiment. It is a schematic top view of the roughening roller of the glass substrate surface treatment apparatus of this embodiment. It is a figure explaining the roughening of the glass substrate by the roughening roller shown in FIG.

  Hereinafter, the manufacturing method and glass substrate surface treatment apparatus of the glass substrate of this embodiment are demonstrated. FIG. 1 is a flowchart showing an outline of the manufacturing process of the glass substrate 100. In FIG. 1, the outline of a process until a glass substrate will be in the state shipped from the state which melts a raw material to a customer etc. is shown.

(1) Manufacturing method of glass substrate Hereinafter, the manufacturing apparatus of the glass substrate of this invention and the manufacturing method of a glass substrate are demonstrated.
Although the glass substrate manufactured in this embodiment is not particularly limited, for example, the vertical dimension and the horizontal dimension are 500 mm to 3500 mm, 1500 mm to 3500 mm, 1800 to 3500 mm, 2000 mm to 3500 mm, etc., and 2000 mm to 3500 mm. Preferably there is.
As for the thickness of a glass substrate, 0.1-1.1 (mm) is mentioned, for example, More preferably, it is a very thin rectangular-shaped board of 0.75 mm or less, for example, 0.55 mm or less, Furthermore, 0.00. A thickness of 45 mm or less is more preferable. As a lower limit of the thickness of a glass substrate, 0.15 mm or more is preferable and 0.25 mm or more is more preferable.

First, the melted glass is formed into a sheet glass, which is a strip glass having a predetermined thickness, by a known method such as a fusion method or a float method (step S1).
Next, the formed sheet glass is sampled on a glass substrate which is a base plate having a predetermined length (step S2). After step 2, the glass substrate obtained by the sampling plate is guided and transported to the heat treatment step while being pinched and held by the transport mechanism, and then the heat treatment step may be performed on the transported glass substrate. .

  The glass substrate after step S2 or heat treatment is conveyed to a cutting process, and is cut into a product size to obtain a glass substrate (step S3). The obtained glass substrate is subjected to end face processing including end face grinding, polishing, and corner cutting (step S4). First cleaning for cleaning the glass substrate in order to remove fine foreign matters and dirt on the glass surface of the glass substrate after the end face processing (step S5).

  The surface treatment step S6 (roughening step Pr1 and rinsing step Pr2) of the present embodiment is performed after the cleaning step S5 immediately after the end face processing. Details of the surface treatment process of this embodiment will be described later.

  After the surface treatment step S6, the second post-cleaning S7 is performed, and thereafter the cleaned glass substrate is optically inspected for scratches, dust, dirt, or scratches including optical defects (step S8). The glass substrate having the quality matched by the inspection is loaded on the pallet and packed as a laminated body alternately laminated with paper protecting the glass substrate (step S9). The packed glass substrate is shipped to a supplier.

As such a glass substrate, the glass substrate of the following glass compositions is illustrated. That is, the raw material of molten glass is prepared so that the glass substrate of the following glass compositions is manufactured.
SiO ₂ 55~80 mol%,
Al ₂ O ₃ 8-20 mol%,
B ₂ O ₃ 0 to 12 mol%,
RO 0 to 17 mol% (RO is the total amount of MgO, CaO, SrO and BaO).

SiO ₂ is preferably 60 to 75 mol%, and more preferably 63 to 72 mol%, from the viewpoint of reducing the heat shrinkage rate.
Among RO, it is preferable that MgO is 0-10 mol%, CaO is 0-15 mol%, SrO is 0-10%, and BaO is 0-10%.

Further, at least SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and RO are included, and the molar ratio ((2 × SiO ₂ ) + Al ₂ O ₃ ) / ((2 × B ₂ O ₃ ) + RO) is 4. The glass which is 5 or more may be sufficient. In addition, it is preferable that at least one of MgO, CaO, SrO, and BaO is included, and the molar ratio (BaO + SrO) / RO is 0.1 or more.

The total content of 2-fold and mol% of RO for the content of mol% of B ₂ O ₃ is 30 mol% or less, it is preferred that preferably 10 to 30 mol%.
Moreover, 0 mol% or more and 0.4 mol% or less may be sufficient as the content rate of the alkali metal oxide in the glass substrate of the said glass composition.
Further, it contains 0.05 to 1.5 mol% of metal oxides (tin oxide and iron oxide) whose valence fluctuates in the glass, and substantially contains As ₂ O ₃ , Sb ₂ O ₃ and PbO. It is not essential but optional.

  The glass substrate manufactured by this embodiment is a glass substrate for flat panel displays, or a glass substrate for curved panel displays, and is suitable, for example, as a glass substrate for liquid crystal displays or a glass substrate for organic EL displays. Furthermore, the glass substrate manufactured in this embodiment is particularly suitable as a glass substrate for LTPS (Low-temperature polysilicon), IGZO (Indium-Gallium-Zinc-Oxide), and TFT displays used for high-definition displays.

  As a method for forming sheet glass from molten glass in this embodiment, a float method, a fusion method, or the like is used. However, a method for manufacturing a glass substrate including offline heat treatment of the glass substrate in this embodiment is a fusion method (overdown). The draw method is suitable for the fusion method because it is difficult to lengthen the slow cooling device on the production line. The thermal shrinkage rate of the glass substrate of this embodiment is 50 ppm or less, preferably 40 ppm or less, more preferably 30 ppm or less, and even more preferably 20 ppm or less. The range of the heat shrinkage rate of the glass substrate before reducing the heat shrinkage rate is preferably 10 ppm to 40 ppm.

(2) Surface treatment step S6
(2-1) Surface treatment method and surface treatment apparatus The surface treatment process of this embodiment will be described in detail. The surface treatment process of this embodiment includes a roughening process (Pr1) in which one surface (first surface) of the main surface of the glass substrate is surface-treated with an etching solution, and etching of the roughened first surface. A rinsing step (Pr2) is also included in which the liquid is washed again with washing water and then washed again, and the second surface that has not been roughened is washed with pure water. Details of the surface treatment S5 will be described later.

  In the surface treatment step S6, only one surface of the main surface of the glass substrate is roughened. The main surface to be roughened is the main surface opposite to the surface on which the TFT and wiring pattern are formed, and no surface treatment (roughening) is performed on the other main surface.

  By performing the roughening treatment, various problems due to charging as described below can be prevented. For example, when a TFT (Thin Film Transistor) and a wiring pattern are formed on a glass substrate, foreign matters such as dust and dust adhere to the glass substrate and the wiring pattern due to charging, and the wiring pattern is lost or peeled off or accumulated. There is a problem that the TFT is destroyed due to the discharge of the electric charge. In addition, the glass substrate may stick to the mounting table due to electrification, and the glass substrate may break when it is peeled off from the mounting table. In order to prevent these problems caused by charging, it is preferable that one side of the main surface of the glass substrate is roughened to prevent charging as much as possible, especially in the fusion method and the overflow downdraw method. The molded glass sheet is preferably subjected to a roughening treatment.

  FIG. 2 is a schematic diagram illustrating an example of the glass substrate surface treatment apparatus 1 that performs the surface treatment step S6. The apparatus shown in FIG. 2 employs a method in which the glass substrate is transported on the etching roller in a horizontal state to be roughened. You may employ | adopt the system of roughening one surface of the main surface of a glass substrate, conveying a glass substrate diagonally or vertically.

  FIG. 3 is a schematic top view of the etching roller used in the glass substrate surface treatment apparatus 1. FIG. 4 is a diagram for explaining the roughening of the glass substrate by the etching roller.

The surface treatment process of the present embodiment will be described with reference to FIG. 2, but the glass substrate surface treatment apparatus 1 (FIGS. 2 to 4) is an example, and the surface treatment process S <b> 6 is other than the glass substrate surface treatment apparatus 1. It can carry out using the apparatus of the structure of this.
The glass substrate surface treatment apparatus 1 roughens one main surface while transporting the glass substrate in the transport direction (specifically, the direction shown by the arrow A1 in FIGS. 2 to 4). Here, the glass substrate surface treatment apparatus 1 roughens the first surface 100a (see FIGS. 2 and 4), which is one main surface of the glass substrate 100, so that the first surface 100a is a predetermined surface. It is rough. Here, the first surface 100a is a surface on which TFT elements and wiring patterns which are thin films are not formed in the manufacturing process of the display device.

<Apparatus configuration of roughening process Pr1>
As shown in FIGS. 2 to 4, the glass substrate surface treatment apparatus 1 mainly includes a plurality of etching rollers 12, a plurality of squeezing rollers 14, and a plurality of etching liquids in the roughening step (Pr1) for surface treatment. Is provided with an etching tank 11, an etching solution tank 16, and an etching solution circulation mechanism.

  The roughening step (Pr1) is surrounded by the housing 2 and may further be provided with temperature control means for managing the temperature of the space in the housing. In the roughening step, the etching solution in the etching tank 11 is vaporized and stays in the air in the housing. Therefore, the air in the housing is appropriately ventilated and is derived from the etching solution contained in the discharged air in the housing. It is preferable to provide a recovery mechanism for recovering the chemical substances.

A. Embodiment 1. FIG. Surface treatment equipment including etchant circulation mechanism (Figure 2)
The surface treatment apparatus in this embodiment is at least:
An etching tank 11 for roughening the first surface of the main surface of the glass substrate;
An etchant tank 16 for adjusting and storing the etchant;
The pipe 15a connecting the etching solution inlet provided in the etching tank and the supply port provided in the etching solution tank, the etching solution discharge port provided in the etching vessel, and the recovery port provided in the etching solution tank are connected. An etchant circulation mechanism 16A having a pipe 15b;
A hydrofluoric acid tank for supplying hydrofluoric acid to the etchant tank as needed;
Is provided.
Furthermore, it is preferable that the etching solution tank has a size twice or more that of the etching tank.

  In the roughening step (Pr1) of the present embodiment, an etching solution tank 16 for adjusting and storing the etching solution is provided, and the etching solution is supplied to the etching tank 11 and circulated by the etching solution tank 16. Further, the etching solution is adjusted while replenishing the etching solution tank 16 with hydrofluoric acid so as to maintain the etching rate in the roughening treatment, and the adjusted etching solution is circulated to the etching tank 11 for use. A pipe is provided between the etching tank 11 and the etching solution tank so that the etching solution MS can be circulated.

  The etching solution tank 16 is connected to a plurality of tanks for supplying constituent materials for adjusting the etching solution (acid components of the etching solution). For example, at least a hydrofluoric acid tank that supplies hydrofluoric acid and a phosphoric acid tank that supplies phosphoric acid are connected to the etchant tank 16, and constituent materials of the etchant are supplied from these tanks. Etching solution is adjusted. The installation of the plurality of tanks for supplying the constituent material (acid component) of the etching solution is determined according to the type of the constituent material. For example, when the etching solution further contains hydrochloric acid, a hydrochloric acid tank is further connected to the etching solution tank 16.

  The etching tank 11 stores an etching solution MS as a processing fluid for processing the surface of the glass substrate 100. In the present embodiment, an etching solution MS that essentially contains hydrofluoric acid and phosphoric acid or an etching solution MS that contains hydrochloric acid in addition to hydrofluoric acid and phosphoric acid is used (the details will be described later). . By etching with the etching liquid MS, the first surface 100a of the glass substrate 100 can obtain a shape having a desired surface roughness, for example, a desired arithmetic average roughness Ra. The arithmetic average roughness Ra is preferably 0.3 nm or more, and more preferably, the arithmetic average roughness Ra is 0.45 nm or more. The upper limit value of the arithmetic average roughness Ra is preferably 0.6 nm or less, and more preferably 0.5 nm or less, from the viewpoint of roughness that prevents the glass substrate from being charged.

  The etching tank 11 is a substantially rectangular parallelepiped container having an open top. In the etching tank 11, an etching solution MS is stored so as to be almost full of the container. The etching tank 11 is arranged at a predetermined interval along the conveyance direction of the glass substrate 100. In the form of FIG. 2, three are arranged. In FIG. 2 of the present embodiment, three etching tanks 11 are arranged, but the number of arrangements may be one, two, or four or more. The number of arrangements is appropriately set based on the number of production, the etching solution and etching rate, the conveyance speed, and the like.

In each etching tank 11, one etching roller 12 is disposed so as to be immersed in the etching solution MS. In the etching solution tank 16, each etching tank 11 is communicated with the etching solution tank 16 by pipes 15a and 15b. The etchant in the etchant tank 16 supplies hydrofluoric acid (HF) and phosphoric acid (H ₃ PO ₄₎ , which are essential components of the etchant MS, and optional hydrochloric acid (HCl). The hydrofluoric acid tank 11 b and the phosphoric acid tank 11 c , And a hydrochloric acid tank 11d through flow rate adjusting valves 11e, 11f, and 11g.

  The etching solution tank 16 is designed so as to have a larger capacity for storing the etching solution than the etching tank 11. The capacity [capacity A] of the etching liquid amount in the etching liquid tank 16 is set to be at least twice as large as the capacity [capacitance B] of the etching liquid amount in the etching tank 11. As long as the installation environment permits, the capacity A should be larger than the capacity B. The size of the capacity A with respect to the capacity B is at least 2 to 15 times, more preferably 5 to 10 times. In this way, by installing the capacitor A larger than the capacitor B, the effect of maintaining the etching rate becomes higher.

  The etching roller 12 absorbs (holds) the etching solution MS and functions as a rotating body that is driven and rotated by a driving motor (not shown). When the etching roller 12 is rotated by the drive motor, the glass substrate 100 that is in contact with the etching roller 12 is transported in the direction in which the plurality of etching rollers 12 are arranged (that is, the transport direction). That is, the etching roller 12 also has a function of transporting the glass substrate 100. A plurality of the etching rollers 12 are arranged at a predetermined interval along the conveyance direction of the glass substrate 100. The plurality of roughening rollers 12 all rotate in the same direction.

  The etching roller 12 is fixed in a state where a part (specifically, the lower part) is immersed in the etching solution MS stored in one etching tank 11. The length in the vertical direction of the portion immersed in the etching liquid MS of the etching roller 12 is appropriately set.

The etching roller 12 includes a core member 12a and a roller member 12b that covers the core member 12a.
The core member 12a includes a shaft core made of SUS or the like and a columnar member made of a vinyl chloride material. The core member 12a may be a carbon shaft. The diameter of the core member 12a is set as appropriate. The core member 12 a is a rotating shaft of the roughening roller 12.

  The roller member 12b is a cylindrical member having an outer diameter larger than that of the core member 12a and having an open center. The roller member 12b is made of a foamed resin that easily absorbs liquid, that is, a sponge. The sponge of the roller member 12b is made of PVA, PU, or the like. The inner surface of the roller member 12b is in contact with the outer surface of the core member 12a. The diameter of the roller member 12b is set as appropriate.

  Here, the etching roller 12 (roller member 12b) absorbs the etching solution MS by being immersed in the etching solution MS. Then, a part of the etching solution MS absorbed by the roller member 12b is supplied and attached to the first surface 100a of the glass substrate 100 that contacts the etching roller 12 (roller member 12b) that absorbs and holds the etching solution MS.

  The squeezing roller 14 has a function of adjusting the amount of the etching liquid MS that is pressed against the etching roller 12 and held by the etching roller 12. The squeezing roller 14 is made of a material having higher rigidity than the roller member 12b, for example, a material such as vinyl chloride or carbon. The squeezing roller 14 is a round bar having a cylindrical shape. The shape of the squeezing roller 14 is not limited to a round bar. As shown in FIG. 3, the squeezing roller 14 is arranged on the upstream side in the transport direction of the glass substrate 100 with respect to the core member 12 a that is the rotation shaft of the etching roller 12.

  The squeezing roller 14 rotates following the rotation of the etching roller 12. Therefore, it rotates in the opposite direction to the etching roller 12. Here, it is not necessary to separately use a motor or the like that rotates the squeezing roller 14, so that the cost can be suppressed.

  As shown in FIG. 4, the squeezing roller 14 is supported by a support member 17 so that the vertical position and the horizontal position with respect to the etching roller 12 can be adjusted. That is, the squeezing roller 14 can adjust the contact position with the etching roller 12. Thereby, the contact pressure of the squeeze roller 14 to the etching roller 12 can be adjusted.

  The etching roller 12 includes a mechanism that can adjust the relative position with respect to the glass substrate 100. That is, the rotating shaft of the etching roller 12 can be moved closer to or away from the glass substrate 100 side. The etching tank 11 is provided with a mechanism that can adjust the liquid level of the etching liquid MS. Thereby, the quantity of the etching liquid MS which the etching roller 12 adheres to the glass substrate 100 can be adjusted.

  The conveyance roller 18 includes a rotation shaft and a plurality of rollers. The roller is a cylindrical member fixed to the rotating shaft and to which an O-ring is attached. When the transport roller 18 is axially rotated by a drive motor (not shown), the glass substrate 100 supported in contact with the upper portion of the transport roller 18 is transported into the housing 2 that performs the roughening process Pr1. A plurality of transport rollers 18 are arranged at predetermined intervals along the transport direction of the glass substrate 100. All the transport rollers 18 rotate in the same direction.

<Roughening process>
In the surface treatment method in the present embodiment, the etching solution is provided between an etching solution tank 16 that adjusts and stores an etching solution containing hydrofluoric acid and an etching tank 11 that is supplied with the etching solution and roughens. Circulating and adjusting the etchant stored in the etchant tank with hydrofluoric acid so as to maintain the etching rate in the etchant tank, and adjusting the etchant 11 to roughen the first surface of the glass substrate Is done.

B. Embodiment 2. FIG. Surface Treatment Method Maintaining Etching Rate The surface treatment step in the method for producing a glass substrate for display according to the present embodiment includes 10 mass% or less hydrofluoric acid and 0.3 mass% or more phosphorus in accordance with the tact time of the previous step. The etching rate is controlled by using an etching solution containing an acid, and the conveyance speed of the surface treatment is determined.
Furthermore, it is preferable that the etching solution is controlled so that the rate of decrease in the etching rate is reduced.
Further, the etching solution is previously adjusted and stored in an etching solution tank, circulates between the etching solution tank and the etching tank for roughening, and is stored in the etching solution tank. The amount of liquid [liquid amount A] is larger than the amount of etching liquid [liquid amount B] maintained in the etching tank, and the liquid amount A is preferably stored and circulated more than twice the liquid amount B. .

<Roughening process>
The glass substrate 100 that has been subjected to the first cleaning step S6 after the end face processing while being transported in a predetermined direction (conveying direction) in a horizontal state is transported by the transport roller 18 while maintaining the state. It enters the housing 2 of the processing device 1.

  The lower surface of the front end portion of the glass substrate 100 in the housing 2 contacts the etching roller 12 and is supported by the etching roller 12. The etching roller 12 (roller member 12b) absorbs the etching liquid MS by being immersed in the etching liquid MS, and the upper surface of the etching roller 12 (roller member 12b) that absorbs the etching liquid MS has a surface. The first surface 100a to be roughened comes into contact, and the glass substrate 100 is transported along the transport direction by the rotational driving of the etching roller 12. At this time, since the etching roller 12 (roller member 12b) absorbs the etching liquid MS, the etching roller 12 (roller member) is formed on the first surface 100a of the glass substrate 100 that contacts the etching roller 12 (roller member 12b). The etchant MS adheres via 12b). Thus, the first surface 100a of the glass substrate is roughened by the etching liquid MS adhering to the first surface 100a while the glass substrate 100 is conveyed by the etching roller 12.

  Since the contact time between the etching roller 12 and the glass substrate 100 in the period from the time when the etching liquid MS adheres to the first surface 100a to the rinsing step Pr2 is the etching period, a desired etching is performed during this etching period. The rotation speed (conveyance speed) of the etching roller 12 that is roughened while conveying the glass substrate 100 can be adjusted so that the amount is achieved. For example, the contact time between the etching roller 12 and the glass substrate 100 is increased by slowing the rotation speed of the etching roller and lengthening the transport time of the glass substrate 100 that transports the top of the etching roller 12, thereby increasing the glass substrate. The degree and shape of the etching of 100a can be adjusted.

(Control of etching rate)
In the present embodiment, for example, the rate of decrease of the etching rate is set to be small based on the composition of etching MS described later. According to the present invention, when the etching solution MS contains at least 0.3% of phosphoric acid together with hydrofluoric acid, the rate of decrease in the etching rate of the etching solution can be significantly reduced. Thus, the etching rate can be maintained and controlled by setting the etching liquid MS to include hydrofluoric acid and phosphoric acid. For example, when it is necessary to increase the conveying speed (processing speed) of the surface treatment process, it is possible to maintain the rate by setting the etching rate to a high level (specifying conditions such as concentration and temperature).

Further, improving the performance of the etching solution leads to an effect of maintaining the etching rate in a long-time continuous processing. For example, the maintenance of the etching rate can be further sustained by suppressing the generation of sludge. According to the present invention, if the etching solution MS is a mixed acid of two types of hydrofluoric acid and phosphoric acid, the amount of sludge generated can be suppressed, so that the etching solution MS contains hydrofluoric acid and phosphoric acid. By being set, the etching rate can be controlled. Furthermore, according to the present invention, since the etching solution contains hydrochloric acid HCl, the effect of suppressing sludge generation can be further increased. In the etching solution MS, in addition to hydrofluoric acid and phosphoric acid, hydrochloric acid HCl is further contained. This reduces the amount of sludge generated and leads to control of the etching rate.
Thus, the etching rate can be controlled so as to be maintained for a long time (the rate of decrease in the etching rate can be reduced). By maintaining the etching rate for a long period of time (decreasing the rate of decrease of the etching rate), the processing speed is stabilized and the production can be leveled in the surface treatment process.
The etching rate is preferably, for example, 0.1 μm / min or more, more preferably 0.2 μ / min or more, still more preferably 0.3 μm / min or more, and particularly preferably 0.5 μm / min or more.

(Control of rate of decrease in etching rate)
About the components contained in the etching solution MS, by using an etching solution containing (a) two kinds of combinations of hydrofluoric acid and phosphoric acid, and (b) three kinds of combinations of hydrofluoric acid, phosphoric acid and phosphoric acid, Etching reduction rate can be controlled small. In other words, the etching rate can be maintained at a high level. For example, when (b) three combinations of hydrofluoric acid, phosphoric acid, and phosphoric acid are used, the rate of decrease in the etching rate is about 5 to 30% under the conditions of processing 100 sheets at 25 ° C. (ie, etching The rate can be maintained at about 70-95%). Therefore, the etching rate reduction rate can be controlled, and long-time continuous processing can be realized.

  Furthermore, hydrofluoric acid may be replenished as necessary in the etching solution tank 16 that supplies the etching solution to the etching tank 11 so that the etching rate in the etching tank 11 does not decrease. Since the hydrofluoric acid HF is consumed during the etching process, the hydrofluoric acid HF can be additionally supplemented to the etching solution tank 16 to compensate for this consumption. The etching liquid MS supplemented with hydrofluoric acid HF is supplied to the etching tank 11 and circulates, so that a decrease in the etching rate in the etching tank 11 can be suppressed. The timing for replenishing hydrofluoric acid HF is not particularly limited. The replenishment of the hydrofluoric acid HF into the etching solution tank 16 may be performed based on the measurement of the etching rate in the etching tank 11 and / or the etching solution tank 16.

(Determination of transfer speed)
Furthermore, the range of the required processing speed (conveyance speed) of the surface treatment process and the range of the etching rate can be specified so as to meet the tact time of the previous process.
Regarding the tact time (target work time), for example, the processing speed of the step immediately before the surface treatment process (first cleaning process S6) can be targeted, and the conveyance speed of the surface treatment process can be set. By setting so as to match the tact time of the immediately preceding process, it is possible to synchronize with the immediately preceding process, making it unnecessary to install an intermediate stock and further improving production efficiency.

(Etching solution circulation)
Etching solution MS is previously adjusted and stored in an etching solution tank. The amount of the etchant [liquid amount A] stored in the etchant tank 16 is preferably 2 to 15 times the amount of the etchant [liquid amount B] maintained in the etching tank 11, and preferably 3 times to It is more preferably 8 times, more preferably 4 to 9 times, still more preferably 5 to 10 times. The volume of liquid A is larger than that of liquid B at such a magnification, and the etching liquid circulates so that the etching rate during the roughening treatment is maintained almost constant for a long time. Can do.
The circulation of the etching liquid MS can be controlled based on the measurement of the etching rate in the etching tank 11 and / or the etching liquid tank 16. For example, when a decrease in the etching rate is recognized, the circulation can be controlled so as to further enhance the circulation of hydrofluoric acid HF replenished in the etching solution tank.
<Apparatus configuration of rinse process Pr2>
In the rinsing step (Pr2), a plurality of transport rollers 18, a distilled water nozzle 25 that applies distilled water to the surface of the glass substrate that is not roughened, a cleaning nozzle 24 that cleans the roughened glass substrate surface, A nozzle 26 that sufficiently rinses the etching solution to be removed, and an arc cutter that removes the liquid adhering to both surfaces of the glass substrate from the surface of the glass substrate so as to remain in the housing.

  The rinsing step (Pr2) is a space surrounded by the housing 4, and the temperature management of the space in the housing may or may not be performed. A slit through which the glass substrate 100 can pass is provided in a portion of the housing wall where the roughening step (Pr1) and the rinsing step (Pr2) are in contact.

  The cleaning nozzle 24 is provided along the transport path of the glass substrate 100 so as to wash away the etching solution MS attached to the first surface 100a of the glass substrate 100, and jets cleaning water toward the first surface 100a. The washing water used for the washing nozzle 24 is not necessarily pure water (distilled water). In the washing water tank 24a, the washed water once used for washing can be stored and circulated and reused for washing the first surface 100a of the glass substrate 100.

  The distilled water nozzle 25 is provided along the transport path of the glass substrate 100 from the main surface opposite to the first surface 100a in order to clean the main surface opposite to the first surface 100a of the glass substrate 100. Water is ejected toward the main surface opposite to the first surface 100a.

  The nozzle 26 ejects cleaning water toward the first surface 100 a in order to sufficiently wash away the etching solution remaining on the first surface 100 a of the glass substrate 100. The nozzle 26 is provided on the first surface 100 a side of the glass substrate 100 along the conveyance path of the glass substrate 100. The cleaning water ejected from the nozzle 26 may be the same pure water ejected from the distilled water nozzle 25, or the same washing water ejected from the cleaning nozzle 24.

  After cleaning the first surface a of the glass substrate 100 and the opposite surface, the liquid is blown off from the surface of the glass substrate by an air cutter, and the housing 4 is moved by the transport roller 18 to perform the second cleaning step of the next step. It is carried out outside.

<Rinsing process>

  After the roughening treatment step (Pr1), the glass substrate 100 moves in the conveying direction during the roughening treatment, so that when the etching liquid MS is attached to a part of the first surface 100a, the tip of the glass substrate 100 is moved. The portion contacts the conveying roller 18 in the housing 4. The glass substrate 100 proceeds to the rinsing process Pr2 by the transport roller 18.

  In the rinsing process Pr2, the first surface 100a is first cleaned with the cleaning water ejected from the cleaning nozzle 24, and the etching liquid MS is almost washed away, and then the first surface 100a is further ejected from the nozzle 26 (reused water). Etc.) At this time, the main surface opposite to the first surface 100 a of the glass substrate 100 is washed with pure water ejected from the distilled water nozzle 25. Further thereafter, air is blown by an air cutter toward the first surface 100a and the main surface opposite to the first surface 100a to blow off the liquid. In this way, the rinsing process Pr2 is completed, and is carried out by the transport roller 18 in order to perform the second cleaning process S8.

(2-2) Etching Solution The etching solution MS in the present invention is an aqueous solution containing at least hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ in pure water (the concentration described below also represents mass%). .
The concentration of phosphoric acid H ₃ PO ₄ in the etching solution MS is 0.3% (mass%) to 10%. If the concentration of phosphoric acid H ₃ PO ₄ exceeds 10%, it is not preferable from the viewpoint of drainage recovery. The concentration of phosphoric acid H ₃ PO ₄ in the etching solution MS is preferably 0.3% to 8%, more preferably 0.5% to 8%, and even more preferably 1%, from the viewpoint of the effect of suppressing the etching rate reduction. ~ 6%. When the etchant MS contains 1% or more of hydrofluoric acid and phosphoric acid H ₃ PO ₄ , hydrofluoric acid, a mixed acid of hydrofluoric acid and hydrochloric acid (same concentration as phosphoric acid), hydrofluoric acid, Compared with sulfuric acid (same concentration as phosphoric acid), the decrease in etching rate can be greatly suppressed under the same temperature condition. That is, the mixed acid of hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ reduces the etching rate. High suppression effect. In the etching solution MS, the concentration of hydrofluoric acid in the mixed acid containing hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ is preferably 0.3% to 10%, preferably 0.3% to 8%, 0 .3% to 6% is more preferable, and 0.3% to 5% is even more preferable. If the concentration of hydrofluoric acid exceeds 5%, the environmental load increases due to the problem of drainage recovery and the like. In the present embodiment, since the hydrofluoric acid concentration of the etching liquid MS can be kept low, the environmental load is small, and the waste liquid treatment cost of hydrofluoric acid can be suppressed.

As the etching solution MS containing hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ is excellent in the etching rate lowering suppression effect, for example, the etching solution MS composed of 5% hydrofluoric acid HF is repeatedly used for 14 hours. The decrease in the etching rate is 45%, and the decrease in the etching rate after 44 hours of repeatedly using the mixed acid etching solution MS of 5% hydrofluoric acid HF and 5% hydrochloric acid HCl is 44%. The decrease in the etching rate after 15 hours of repeated use of the mixed acid etching solution MS of 5% hydrofluoric acid HF and 5% phosphoric acid H ₃ PO ₄ is 15%. Thus, the decrease in the etching rate of the glass substrate 100 in the etching solution MS containing hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ is extremely small. These etching rates are all measured under the same temperature conditions.

Further, when the etching solution MS contains 1% or more of hydrofluoric acid and phosphoric acid H ₃ PO ₄ , compared with hydrofluoric acid, hydrofluoric acid and sulfuric acid (same concentration as phosphoric acid) under the same concentration of hydrofluoric acid. The amount of sludge generated can be kept low, and the mixed acid of hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ also has an effect of suppressing the amount of sludge generated.
The etching liquid MS containing hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ is excellent in the effect of suppressing the amount of sludge generation. For example, in the case of an etching liquid MS made of hydrofluoric acid HF with a sludge generation amount of 5% In contrast, the etching solution MS of a mixed acid of 5% hydrofluoric acid HF and 5% phosphoric acid H ₃ PO ₄ is 20 to 30% less. Thus, the mixed acid of hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ is excellent in the effect of suppressing the amount of sludge.

For etchant MS containing hydrofluoric acid HF and phosphoric acid _H 3 PO _4, hydrofluoric acid HF and the concentration ratio of the phosphoric acid _H 3 PO _4: The (hydrofluoric acid), about 1: 1 to 30: is 1 , Preferably 1: 1 to 10: 1. The etching liquid MS of the present embodiment is a mixed acid containing hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ as essential components. By using hydrofluoric acid and phosphoric acid as essential components, the etching rate is reduced and the effect is reduced. It has two simultaneous effects of suppressing the amount of sludge generated in the surface etching process.

  Conventionally known solutions containing sodium fluoride and phosphoric acid are not suitable as etching solutions for continuous roughening treatment because the etching rate itself is low.

The etching solution MS is mixed with the above combination (two kinds of mixed acids with hydrofluoric acid and phosphoric acid, or three kinds of mixed acids with hydrofluoric acid and phosphoric acid and hydrochloric acid), if necessary, sulfuric acid H ₂ SO ₄ , nitric acid HNO _3, etc. May be combined.

In the present embodiment, the etching solution MS may further contain hydrochloric acid HCl in addition to hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ . In the case of three types of mixed acid in which hydrochloric acid HCl is combined with hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ , generation of sludge can be further suppressed. Therefore, it is preferable that the etching liquid MS of this embodiment further includes hydrochloric acid HCl together with hydrofluoric acid HF and phosphoric acid H ₃ PO _{4. In} this case, the effect of suppressing the amount of sludge can be further enhanced.
In the etching solution MS, when hydrochloric acid HCl is combined with hydrofluoric acid HF and phosphoric acid H ₃ PO ₄ , the concentration of hydrochloric acid HCl is 0.3 mass% to 15 mass%, preferably hydrochloric acid HCl 0.3 mass% to 10 mass%. is there. In this case, the etchant MS, hydrofluoric acid HF is 0.3 wt% to 10 wt%, 0.3% to 10 wt% phosphoric acid _H 3 PO _4, the hydrochloride HCl 0.3% to 15% by weight It is. The concentration ratio of hydrofluoric acid HF and hydrochloric acid HCl (hydrofluoric acid: hydrochloric acid) when hydrochloric acid is used as the etching solution MS is approximately 1:10 to 5: 1.

(Roughening temperature)
The etching rate varies depending on the temperature of the etching solution MS. The temperature of the etching liquid MS is appropriately determined so as to obtain a predetermined etching rate. During the roughening treatment, it is preferable to keep the temperature of the etching solution MS constant so that the etching rate becomes constant. In this embodiment, the temperature of the etching MS is controlled between 20 ° C. and 30 ° C. Since the processing environment is deteriorated when the etching solution is vaporized, the temperature of the etching solution MS preferably does not exceed 40 ° C. Further, when the temperature of the etching MS is lower than 20 ° C., it becomes difficult to obtain a predetermined etching rate.

(Roughening time)
Roughening treatment time determines the surface roughness (arithmetic mean roughness Ra) obtained by roughening, and is used for the roughing treatment speed and roughening treatment based on the tact time of the previous process. This is set together with the number of etching rollers to be performed, the composition of the etching liquid MS used for the roughening treatment, and the etching rate.
The surface roughness obtained by roughening is preferably 0.30 nm or more, and more preferably, the arithmetic average roughness Ra is 0.40 nm or more. The upper limit value of the arithmetic average roughness Ra is preferably 0.60 nm or less, and more preferably 0.50 nm or less.

(2-3) Features of thin glass <Glass composition>
Examples of the glass composition to which the present embodiment is applied include the following (mass% display).
SiO _2: 50~70% _{(preferably, 57~64%), Al 2 O} 3: 5~25% ( _{preferably, 12~18%), B 2 O} 3: 0~15% ( preferably, 6 ~ 13%), and may optionally contain the following composition. As optional components, MgO: 0 to 10% (preferably 0.5 to 4%), CaO: 0 to 20% (preferably 3 to 7%), SrO: 0 to 20% (preferably, from 0.5 to 8%, more preferably 3~7%), BaO: 0~10% ( preferably 0-3%, more preferably _{0~1%), ZrO 2: 0~10} % ( preferably 0 to 4%, more preferably 0 to 1%). Furthermore, it is more preferable that R ′ ₂ O: more than 0.10% and 2.0% or less (provided that R ′ is at least one selected from Li, Na, and K).
_{Alternatively,} SiO 2: _{50~70% (preferably, 55~65%), B 2 O} 3: 0~10% ( _{preferably, 0~5%, 1.3~5%),} Al 2 O 3: 10-25% (preferably 16-22%), MgO: 0-10% (preferably 0.5-4%), CaO: 0-20% (preferably 2-10%, 2-6 %), SrO: 0 to 20% (preferably 0 to 4%, 0.4 to 3%), BaO: 0 to 15% (preferably 4 to 11%), RO: 5 to 20% (preferably Is preferably 8 to 20%, 14 to 19%) (wherein R is at least one selected from Mg, Ca, Sr and Ba). Furthermore, it is more preferable that R ′ ₂ O contains more than 0.10% and 2.0% or less (provided that R ′ is at least one selected from Li, Na and K).
<Young's modulus>
As a Young's modulus of the glass plate to which this embodiment is applied, for example, 72 (Gpa) or more is preferable, 75 (Gpa) or more is more preferable, and 77 (Gpa) or more is even more preferable.
<Strain point>
As a distortion rate of the glass substrate to which this embodiment is applied, 650 degreeC or more is preferable, for example, 680 degreeC or more is more preferable, 700 degreeC or more and 720 degreeC or more are still more preferable.

The glass substrate surface treatment apparatus 1 (FIG. 2) described above was used to roughen a thin glass sheet having a thickness of 0.5 mm.
As for the etching solution MS, an etching solution (etching solution MS1) containing 3% hydrofluoric acid HF, 9% hydrochloric acid HCl, and 1% phosphoric acid H ₃ PO ₄ , 5% hydrofluoric acid HF, and 9% hydrochloric acid. Using two types of etching liquid (etching liquid MS2) containing HCl and 2% phosphoric acid H ₃ PO ₄ , a surface roughening treatment was performed at an etching rate of 1.6 μm / min under the condition of 25 ° C. did.
The etching solution MS is adjusted and stored in advance in the etching solution tank, and the amount of the etching solution [liquid amount A] stored in the etching solution tank 16 is the amount of etching solution [liquid amount] maintained in the etching tank 11. B] and was circulated.

In this way, the etching MS is adjusted, and the etching liquid is circulated so that the liquid volume A is 5 times the liquid volume B, so that the continuous processing is continued for 24 hours while suppressing the decrease in the etching rate. In addition, the etching rate of 1.6 μm / min (at 25 ° C.) could be maintained. In addition, continuous roughening treatment could be performed without causing line stoppage due to sludge generation.
It was also demonstrated that the etching rate can be specified from the range of 1.3 μm / min (under 20 ° C.) to 3.5 μm / min (under 30 ° C.) to determine the conveyance speed.

Etching rate reduction rate is 5% under the condition of processing 100 sheets at 25 ° C. using 3 kinds of mixed acid of hydrofluoric acid HF, phosphoric acid H ₃ PO ₄ and hydrochloric acid HCl (without replenishment of hydrofluoric acid HF) It has been demonstrated that 30% can be achieved. Therefore, the conveying speed of the roughening treatment was set high, and a long-time continuous reaction was possible.

  As a result of being able to maintain the processing speed of the surface treatment to meet the tact time of the previous process (end face processing S5 and first cleaning S6), the production of the surface treatment process is more leveled and the intermediate stock is reduced. .

  The first surface 100a of the glass substrate subjected to the roughening treatment has a surface roughness that can suppress charging of the surface of the glass substrate, and a surface roughness that does not impair the strength of the glass substrate 100 is obtained. Ra (JIS B0601-2001) was 0.42 to 0.48 nm.

As described above, in the surface treatment apparatus provided with the etching solution circulation mechanism of the present invention or the surface treatment method of the present invention, 10 to match the tact time of the previous step (end surface processing S5 and first cleaning S6). According to the surface treatment method for roughening, the etching rate is controlled using an etching solution containing hydrofluoric acid of not more than mass% and phosphoric acid of not less than 0.3 mass%, and the conveying speed of the surface treatment is determined.
The etching rate can be maintained while suppressing the decrease in the etching rate, and the amount of sludge contained in the etching solution is suppressed (that is, the etching rate can be maintained at a high level for a long time). Thereby, the quality of a roughening process can be achieved efficiently.
Therefore, a glass substrate useful for a high-definition display can be provided by an economically excellent method.

  As mentioned above, although the manufacturing apparatus of the glass substrate of this invention and the manufacturing method of the glass substrate were demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, various improvement and change You may do.

DESCRIPTION OF SYMBOLS 1 Glass substrate surface treatment apparatus 2, 4 Housing 11 Etching tank 16 Etching liquid tank 11b Hydrofluoric acid tank 11c Phosphoric acid tank 11d Hydrochloric acid tank 11e, 11f, 11g Flow rate adjustment valve 12a Core member 12b Roller member 14 Contact member 15 Piping 18 Conveying roller 24 Washing water nozzle 24a Washing tank 1
25 Distilled water nozzle 25a Distilled water tank 26 Washing water nozzle 26a Washing tank 2
100 Glass substrate 100a 1st surface

Claims (6)

A method for producing a glass substrate for a display, comprising a surface treatment step of continuously roughening the first surface of the glass substrate by attaching an etching solution to the first surface,
In the surface treatment step, the etching rate is controlled using an etching solution containing 10% by mass or less hydrofluoric acid and 0.3% by mass or more phosphoric acid in accordance with the tact time of the previous step, and the surface treatment transport speed. The manufacturing method of the glass substrate for displays.   The said etching liquid is a manufacturing method of the glass substrate for a display of Claim 1 with which the decreasing rate of an etching rate (under the conditions of a 100 sheet process at 25 degreeC) is set to 5%-30%. In the surface treatment step, the etchant is preliminarily adjusted and stored in an etchant tank, and circulates between the etchant tank and the roughening etching tank.
Further, the amount of the etching solution [liquid amount A] stored in the etching solution tank is larger than the amount of the etching solution [liquid amount B] maintained in the etching tank. The method for producing a glass substrate for display according to claim 1 or 2, wherein the glass substrate is circulated by being stored more than twice.   The method for producing a glass substrate for a display according to any one of claims 1 to 3, wherein the arithmetic average roughness Ra of the first surface after the surface treatment step is 0.40 nm or more.   The etching solution contains at least 0.3 to 10% by mass of hydrofluoric acid, 0.3 to 10% by mass of phosphoric acid, and 0.3 to 15% by mass of hydrochloric acid. The manufacturing method of the glass substrate for displays in any one.   The method for manufacturing a glass substrate for a display according to any one of claims 1 to 5, wherein, in the surface treatment step, the first surface is etched at an etching rate at 25 ° C of 0.1 µm / min or more.

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