TWI383963B - Process for producing polished glass substrate,polished glass substrate and surface-polishing liquor - Google Patents

Description

Method for manufacturing a ground glass substrate, polishing a glass substrate and a surface polishing liquid

The present invention relates to a method for producing a ground glass substrate by immersing a glass substrate in a chemical polishing liquid containing hydrofluoric acid and performing surface polishing to a desired substrate thickness; in particular, it is suitable for manufacturing a glass substrate for liquid crystal display. Production method.

In recent years, the glass substrate for liquid crystal display (hereinafter simply referred to as "glass substrate") is preferably as thin as possible for the purpose of reducing the energy consumption of the display product, and the thickness of the glass substrate (hereinafter simply referred to as "glass thickness"). Therefore, a method of manufacturing a ground glass substrate in which a glass polishing liquid is thinned by chemical polishing on one or both sides of a glass substrate by a chemical polishing liquid containing hydrofluoric acid is conventionally used.

For example, Patent Document 1 (Japanese Laid-Open Patent Publication No. 2003-20255) discloses a polishing process using a chemical processing liquid containing hydrofluoric acid and one or more inorganic acids selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid. An exemplified embodiment is to grind to a desired glass substrate thickness using a chemical processing fluid containing 5% hydrofluoric acid, 10% hydrochloric acid, and 5% nitric acid. However, in such conventional techniques, since it is ground to a desired thickness of the glass substrate in a single step, it can be polished to a desired glass thickness, but on the surface of the glass substrate (hereinafter simply referred to as "glass surface"). There will be problems with smoothness. In particular, microcracks originally present on the surface of the glass may grow into large depressions (hereinafter referred to as "dimples") during the chemical polishing process, causing serious problems of defective products, and it is difficult to use the above-mentioned conventional techniques. Suppress these dents It happened.

As a means for solving such a problem, for example, the method disclosed in Patent Document 2 (Japanese Patent Laid-Open Publication No. 2005-343742) is: using 10 to 30% by weight of hydrofluoric acid and 20 to 50% by weight of sulfuric acid. % of the surface polishing liquid is polished at a polishing rate of 1 μm/sec or more for a few seconds, and is subjected to surface polishing for suppressing damage of a diameter of 40 μm or more from being expanded to a diameter of 100 μm or more, and then immersed in a medium to low concentration. In the latter stage of hydrofluoric acid, the latter stage is ground to the desired thickness of the glass substrate. However, according to this method, although the enlargement of the dent is suppressed in the surface polishing of the front stage polishing, since the contact time with the polishing liquid is short, it is difficult to control the entire glass substrate to be uniformly polished, and the smooth portion is generated. A step difference of several μm will have a problem that it will expand in the latter stage of grinding.

In the method of chemical polishing of a glass substrate, a plurality of polishing liquids having different chemical polishing rates are used, and the polishing rate is fast in order. The polishing liquid is subjected to a number of grinding treatments to a slow polishing liquid, thereby suppressing the generation of dents. However, according to this method, even if the generation of dents can be suppressed, a large number of steps are required, which are considered to be inconsistent with economic benefits from the viewpoints of productivity and equipment cost.

Further, in Patent Document 4 (Japanese Laid-Open Patent Publication No. 2005-11894), a method proposed is: when chemically polishing a glass substrate, first immersing in a liquid (inert liquid) which does not react with the polishing liquid, The pores present on the surface of the glass are filled with an inert liquid, and then chemically polished to suppress the growth of pores into pits; an example of the inert liquid is a perfluoroalkyl compound or the like. Of course On the other hand, according to this method, even if the generation of dents can be suppressed, since wastewater containing an organic compound is generated, there is a problem that it is necessary to carry out wastewater treatment.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-20255

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2005-343742

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2004-77640

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2005-11894

An object of the present invention is to solve the problems of the prior art, and to provide a method for manufacturing a glass substrate having a smooth glass surface without inhibiting the growth of the dent and surface-polishing the glass substrate to obtain no dents and steps; The ground glass substrate produced by this method, and the surface polishing liquid.

The present invention relates to a method for producing a ground glass substrate, a polished glass substrate, and a surface polishing liquid.

(1) A method for producing a ground glass substrate, wherein a glass substrate is immersed in a polishing liquid containing hydrofluoric acid, and a surface is chemically polished to produce a polished glass substrate; and the surface smoothing step is included The glass substrate is immersed in a surface polishing liquid containing 40 to 90% by weight of sulfuric acid and 0.4 to 4% by weight of hydrofluoric acid, and is subjected to surface polishing to suppress the growth of the dents to form a smooth glass surface.

(2) A method for producing a ground glass substrate by immersing a glass substrate in a polishing liquid containing hydrofluoric acid, and chemically grinding the surface to produce a ground A glass-grinding substrate is characterized in that it comprises the following steps: a surface smoothing step of immersing a glass substrate in a surface polishing liquid containing 40 to 90% by weight of sulfuric acid and 0.4 to 4% by weight of hydrofluoric acid and performing surface grinding. Suppressing the growth of the dent to form a smooth glass surface; in the subsequent grinding step, the surface smoothed glass substrate is immersed in a slurry containing 2 to 30% by weight of hydrofluoric acid, and then ground to a desired substrate thickness. .

(3) The method according to (1) or (2) above, wherein the surface polishing liquid is a polishing liquid containing 50 to 85% by weight of sulfuric acid and 0.5 to 4% by weight of hydrofluoric acid.

(4) The method according to any one of (1) to (3) above wherein the glass substrate is a glass substrate for a liquid crystal display.

(5) A ground glass substrate produced by the method according to any one of the above (1) to (4), wherein the growth of the dent is suppressed and the surface of the glass is smooth.

(6) A surface polishing liquid for immersing a glass substrate and performing surface polishing to suppress growth of dents to form a smooth glass surface; the system comprises 40 to 90% by weight of sulfuric acid and 0.4 to 4% by weight of hydrogen fluoride. Acid surface grinding fluid.

The glass substrate to be produced by the present invention is a glass substrate for a flat panel display such as a liquid crystal display, an organic electroluminescence display or a plasma panel display, and is particularly suitable for a glass substrate for a liquid crystal display. The material of the glass substrate, such as a glass substrate such as an aluminoborosilicate glass substrate, is generally used for polishing.

In the method for producing a ground glass substrate of the present invention, the surface of the surface is polished by chemical polishing by immersing the glass substrate in the surface polishing liquid. In the sliding step, a glass substrate having a smooth glass surface can be formed by suppressing the growth of the dent. The surface polishing liquid which can be used in the surface smoothing step includes a surface polishing liquid containing 40 to 90% by weight of sulfuric acid and 0.4 to 4% by weight of hydrofluoric acid, particularly 50 to 85% by weight of sulfuric acid and 0.5 to 0.5% by weight. A surface grinding liquid of 4% by weight of hydrofluoric acid is preferred. The remainder of the surface polishing liquid is mainly water, and may also contain other solvents, surfactants, stabilizers and the like. When the concentration of sulfuric acid or the concentration of hydrofluoric acid in the surface polishing liquid is lower than the lower limit, the effect of suppressing the growth of the dent is weak, and if the concentration of sulfuric acid or the concentration of hydrofluoric acid is higher than the above upper limit, the surface of the glass is likely to be in a stepwise manner. It is not good.

The temperature of the surface polishing liquid in the surface smoothing step is not particularly limited, and may be normal temperature, but the higher the temperature, the greater the suppression effect of the dent. Therefore, the surface smoothing step can be performed by heating to 30 to 50 °C. The immersion of the polishing liquid should be 1 to 90 minutes, preferably 5 to 30 minutes. If it is less than 1 minute, the growth inhibition effect of the dent is not good, and in the case of immersion for 90 minutes or more, the productivity of the polishing process of the glass substrate is lowered. The surface smoothing step can be surface-polished to a desired substrate thickness. However, in the case of combining the subsequent polishing steps, the surface smoothing step does not have to be ground to a desired substrate thickness as long as smoothness can be obtained. The glass surface is sufficient, so it can be set as the above immersion time.

By the surface polishing by the surface polishing liquid in the surface smoothing step, it is possible to form a glass substrate having a smooth glass surface while suppressing the growth of the dent. The mechanism for suppressing the growth of dents to form a smooth glass surface has not been elucidated, but it is presumed as follows: Microcracks originally present on the surface of the glass rapidly grow and expand during chemical polishing. As a mechanism for suppressing this, it is in contact with a highly viscous polishing liquid containing an appropriate concentration of hydrofluoric acid, and the fluoride is precipitated into the microcracks and sealed, and the flat portion is first ground to eliminate cracks.

Patent Document 2 discloses a method of using a surface polishing liquid containing 10 to 30% by weight of hydrofluoric acid and 20 to 50% by weight of sulfuric acid, and polishing at a polishing rate of 1 μm/sec or more for several seconds. The surface of the front-stage polishing having a diameter of 100 μm or more is expanded to prevent the damage from being expanded to a diameter of 100 μm or more. However, according to this method, although the damage of the surface can be suppressed in the surface polishing of the front-stage polishing, the contact time with the polishing liquid is short. Therefore, it is difficult to control the entire glass substrate to be uniformly polished, and a step of several μm is likely to occur in the smooth portion, and this step is enlarged in the subsequent polishing.

These problems in Patent Document 2 are considered to be due to the high concentration of hydrofluoric acid. Hydrofluoric acid is effective for the dissolution of glass. Basically, the higher the concentration of hydrofluoric acid, the faster the dissolution rate, and the control becomes difficult. Other acids such as sulfuric acid have an effect on the adjustment of the dissolution state of the glass, but have no direct effect on the dissolution of the glass itself.

In the present invention, in the surface smoothing step, the dissolution of the glass is uniformized by using a low concentration of hydrofluoric acid. In this case, by containing a high concentration of sulfuric acid as a highly viscous polishing liquid, the fluoride which is deposited in the microcrack is occluded, and the flat portion is first polished to eliminate cracks, thereby forming no dents and steps. Smooth glass surface. In the surface smoothing step, after forming a smooth glass surface, a smooth glass surface can be maintained even after the latter polishing to a desired thickness with a high hydrofluoric acid concentration.

In the surface smoothing step, by immersing in the surface polishing liquid, the concave is suppressed The substrate which grows to form a smooth glass surface, can be immersed in a polishing liquid having a medium to low concentration hydrofluoric acid in a subsequent polishing step, and is subjected to post-stage polishing to a desired substrate thickness, thereby producing a target. A ground glass substrate having a substrate thickness. The polishing liquid in the subsequent stage is a polishing liquid containing 2 to 30% by weight of hydrofluoric acid (preferably 5 to 30% by weight), and may further contain inorganic acid other than hydrofluoric acid such as hydrochloric acid, sulfuric acid, phosphoric acid or nitric acid, and inorganic The total amount of acid is preferably 4 to 40% by weight, preferably 10 to 20% by weight. The remainder of the latter slurry is mainly water, and may also contain other solvents, surfactants, stabilizers and the like.

The post-grinding step is a conventional grinding process for grinding to a desired substrate thickness to produce a method of grinding a glass substrate. Therefore, in the post-stage grinding step, conditions, operations, and the like which are conventionally performed in the method of grinding to the desired thickness of the glass substrate can be employed. The temperature of the polishing liquid in the subsequent stage in the subsequent polishing step is not particularly limited, and may be a normal temperature, and is usually carried out at a temperature of about 15 to 50 ° C for the subsequent stage polishing step. The immersion time of the latter polishing liquid is 30 to 150 minutes, which is the time required for polishing to the thickness of the target glass substrate.

The ground glass substrate of the target glass substrate thickness can be manufactured by grinding to the desired thickness of the glass substrate in the subsequent stage grinding step. In this case, in the present invention, surface polishing is performed by suppressing the growth of the dent by the surface smoothing step, whereby a smooth glass surface can be obtained, so in this state, even in the subsequent polishing step, the polishing is performed to a desired level. The thickness of the glass substrate does not cause dents and step on the surface of the glass, and a ground glass substrate having a smooth glass surface can be obtained. Therefore, by performing chemical polishing of the glass substrate for liquid crystal display by the above method, it is possible to provide suppression of dent generation and maintain a good surface state. High quality products.

According to the present invention, by immersing the glass substrate in a surface polishing liquid containing 40 to 90% by weight of sulfuric acid and 0.4 to 4% by weight of hydrofluoric acid in the surface smoothing step and performing surface polishing, the growth of the dent is suppressed. The surface is ground to obtain a glass substrate having a smooth glass surface without dents and steps.

Moreover, in the surface smoothing step, the surface-polished surface of the glass substrate is polished to a desired thickness of the glass substrate in the subsequent grinding step to produce a smooth glass having no dents and steps on the glass surface. A ground glass substrate on the surface.

The ground glass substrate obtained in the present invention has no unevenness and step on the surface of the glass, has a smooth glass surface, and has a desired substrate thickness.

Since the surface polishing liquid used in the surface smoothing step of the present invention contains sulfuric acid and hydrofluoric acid at the above concentrations, by immersing the glass substrate therein and performing surface polishing, it is possible to suppress the growth of the dents and form a smooth Glass surface.

Hereinafter, an example of a method for producing a glass substrate for a liquid crystal display according to an embodiment of the present invention will be described with reference to FIG. 1. However, the present invention is not limited to the type of the glass substrate used in the embodiment, the type of the polishing liquid tank, and The use of various instruments and devices such as holders for glass substrates.

In Fig. 1, 1 is a surface polishing liquid tank, 2 is a first water washing tank, 3 is a rear stage grinding tank, 4 is a second water washing tank, and 5 is a final water washing tank.

The glass substrate 20 for liquid crystal displays has various sizes. As shown in Figure 1 The surface smoothing tank 1 filled with the surface polishing liquid 6, the first water washing tank 2 filled with the washing water 7, the grinding tank 3 after the finishing stage 8 is filled, and the washing water 9 is filled. The second water washing tank 4 and the final water washing tank 5 filled with the washing water 10; the deck container 21 accommodating the glass substrate 20 is sequentially introduced into and out of the surface smoothing tank 1, the first water washing tank 2, the rear grinding tank 3, and the 2 The water washing tank 4 and the final water washing tank 5 are chemically polished.

First, as a surface smoothing step, the cartridge 21 is immersed in the surface smoothing tank 1 filled with the surface polishing liquid 6, and the surface is ground by the air supply device 11 by means of gas or gas bubbling. The liquid 6 was subjected to surface grinding. The immersion time of the surface smoothing tank 1 is preferably from 1 to 90 minutes, preferably from 5 to 30 minutes. If it is 1 minute or less, the effect of suppressing the growth of the dent is not good, and if it is immersed for a long time of 90 minutes or longer, the productivity of the polishing process of the glass substrate 20 is lowered, which is not preferable. Further, the temperature of the surface polishing liquid 6 in the surface smoothing step is not particularly limited, and it is known that the higher the temperature, the better the suppression effect of the dent. In terms of liquid temperature, the surface polishing liquid 6 can be heated to 30 to 50 ° C.

Then, the card seat 21 is taken out from the surface smoothing tank 1 and immediately immersed in the first water washing tank 2, and the air blowing device 12 is stirred by means of blowing or the like, and the surface polishing liquid adhering to the surface 20 is washed with the washing water 7. Net removal. Next, the cartridge 21 is taken out from the first washing tank 2, and immersed in the grinding tank 3 after the finishing of the polishing liquid 8 in the subsequent stage, and the polishing is performed in the subsequent stage polishing step. At this time, the polishing liquid 8 in the subsequent stage is preferably kept in a uniform flow by means of blowing by the air supply means 13 or by means for circulating the polishing liquid or the like. If the flow is insufficient, precipitates will accumulate on the surface of the glass substrate 20, causing the polishing rate to not occur. Both of them result in uneven grinding thickness, resulting in poor surface finish. The polishing time is performed by the polishing liquid 8 in the subsequent stage, and the polishing time can be set according to the predetermined glass thickness.

Immediately after the completion of the subsequent polishing in the subsequent grinding tank 3, the cartridge 21 is taken out and immersed in the second washing tank 4 filled with the washing water 9, and the substrate 20 is washed with water. The washing water may be stirred by a blower from the air supply device 14, or the washing water may be circulated to improve the water washing effect. Finally, the cartridge 21 is moved to the final washing tank 5, and the same operations as those of the first and second water washing tanks 2, 4 are performed to complete the chemical polishing.

[Examples] (Examples 1 to 9)

A sandpaper of appropriate thickness was laid, and aluminoboroic acid glass was cut horizontally into 10 cm squares, and a specific load was applied thereto to give a scratch on the surface of the glass as a sample to verify the dent suppression effect.

The test apparatus is used to simulate the small substrate storage deck 21, the surface smoothing tank 1, the rear grinding tank 3, the first water washing tank 2, the second water washing tank 4, and the final water washing tank 5 of FIG. Method 1 is used for grinding. The composition, temperature, and immersion time of the surface polishing liquid 6 of the surface smoothing tank 1 in the surface smoothing step are shown in Table 1. In the subsequent polishing step, the polishing by the polishing liquid 8 in the subsequent stage of the subsequent grinding tank 3 is carried out at room temperature for about 50 minutes by a polishing liquid containing 10% by weight of hydrofluoric acid and 5% by weight of sulfuric acid. After the grinding, the surface of the sample was observed by microscopic observation of the size of the dent which was grown starting from the artificial scratch, and the number thereof was calculated. Moreover, the surface state of the glass substrate was visually observed. The results are shown in Table 1.

(Comparative examples 1 to 4)

In the same manner as in the first to the ninth embodiments, the composition, temperature, and immersion time of the surface polishing liquid 6 of the surface smoothing tank 1 in the surface smoothing step were changed as shown in Table 1, and processed. The results are shown in Table 1.

(Comparative Example 5)

In Examples 1 to 9 and Comparative Examples 1 to 4, the surface smoothing step by the surface polishing liquid 6 of the surface smoothing tank 1 and the water washing of the first water washing tank 2 were not performed, and only the rear grinding tank was performed. The treatment of the polishing liquid 8 in the latter stage of 3 is compared with the washing in the second and final washing tanks 4, 5. The results are shown in Table 1.

Evaluation method: In the evaluation method in Table 1, the number of pits each satisfying a diameter of 50 μm or more was reduced as compared with Comparative Example 5, and the absence of the above-described step was judged to be an inhibitory effect.

From the results of Table 1, it can be determined that the tendency of the reduction of the dent and the tendency of the step are determined by the balance between the concentration of sulfuric acid and the concentration of hydrofluoric acid and the immersion time in the surface polishing liquid. That is, as a result of Examples 1, 2, 6, 8, and 9, under the conditions of a sulfuric acid concentration of 60 to 85% by weight and a hydrofluoric acid concentration of 1.1 to 3.9 % by weight, dents having a diameter of 150 μm or more were not confirmed. Moreover, the total number of dents was also reduced to about 1/2 to 1/7 of Comparative Example 5, and no step difference was produced.

Further, in Example 3 in which sulfuric acid was 70% and hydrofluoric acid concentration was low (0.9% by weight), the number of dimples was reduced to 1/10 of Comparative Example 5 by lengthening the immersion time, and was set to be longer. The immersion time can improve the dent suppression effect.

Further, in Example 4 in which the hydrofluoric acid concentration was low (0.5% by weight), and in Example 5 in which the sulfuric acid concentration was low (50% by weight), and in Example 7, the dents having a diameter of 150 μm or more were not included. The number can be reduced to the extent of 4/5 of Comparative Example 5.

On the other hand, Comparative Example 3 in which the sulfuric acid concentration exceeded 90% by weight, Comparative Examples 1 and 2 in which the hydrofluoric acid concentration exceeded 4% by weight, and Comparative Example in which the sulfuric acid concentration was as low as 30% by weight and the hydrofluoric acid concentration was as high as 5.5% by weight. In any of the four, it is confirmed that there is a suppression effect of the dent, but it is easy to cause a step difference, which is not preferable.

From the above results, it is known that 40 to 90% by weight of sulfuric acid (preferably 50 to 85% by weight) and 0.4 to 4% by weight of hydrofluoric acid (0.5 to 4% by weight) are required in order to prevent the generation of the step and suppress the generation of the indentation. Grinding is carried out within a concentration range of better.

(Example 10) <Test results of real substrate>

The test was carried out using an aluminoborosilicate glass substrate (4th generation size). The surface polishing liquid 6 was an aqueous solution of 70% by weight of sulfuric acid and 1.3% by weight of hydrofluoric acid, and the glass substrate was immersed in a surface polishing liquid to polish the surface of the glass. At this time, the temperature of the surface polishing liquid was set to 15 ° C, and the time during which the glass substrate was immersed in the polishing liquid was about 15 minutes, and the surface polishing liquid was agitated by blowing. After the surface polishing is completed, the glass substrate is washed with water. Then, it is processed to a desired substrate thickness by a surface polishing liquid containing 10% by weight of hydrofluoric acid and 5% by weight of sulfuric acid. As a result, the failure rate in the practical evaluation benchmark was reduced to 1/3.

(Example 11) <Test results of real substrate>

The test was carried out using an aluminoborosilicate glass substrate (4th generation size). The surface polishing liquid 6 used an aqueous solution of 60% by weight of sulfuric acid and 1.4% by weight of hydrofluoric acid, and the glass substrate was immersed in a surface polishing liquid to polish the surface of the glass. At this time, the temperature of the surface polishing liquid was set to 15 ° C, and the time during which the glass substrate was immersed in the polishing liquid was about 70 minutes, and the surface polishing liquid was agitated by blowing. After the surface polishing is completed, the glass substrate is washed with water. Then, it is processed to a desired substrate thickness by a surface polishing liquid containing 10% by weight of hydrofluoric acid and 5% by weight of sulfuric acid. As a result, the failure rate in the practical evaluation standard was reduced to 1/20.

(industrial availability)

The manufacturing method of the present invention can be utilized as a method of manufacturing a glass substrate for liquid crystal display by impregnating a glass substrate with a chemical polishing liquid containing hydrofluoric acid and performing surface polishing to a desired glass substrate thickness. law.

1‧‧‧Surface smoothing tank

2‧‧‧1st washing tank

3‧‧‧ Rear grinding groove

4‧‧‧2nd washing tank

5‧‧‧Final washing tank

6‧‧‧ Surface grinding fluid

7‧‧‧ Washing water

8‧‧‧After the slurry

9‧‧‧ Washing water

10‧‧‧ Washing water

11‧‧‧Air supply device

12‧‧‧Air supply device

13‧‧‧Air supply device

14‧‧‧Air supply device

15‧‧‧Air supply device

20‧‧‧ glass substrate

21‧‧‧Small substrate storage deck

1 is a flow chart showing an embodiment of a method of manufacturing a glass substrate for a liquid crystal display.

1‧‧‧Surface smoothing tank

2‧‧‧1st washing tank

3‧‧‧ Rear grinding groove

4‧‧‧2nd washing tank

5‧‧‧Final washing tank

6‧‧‧ Surface grinding fluid

7‧‧‧ Washing water

8‧‧‧After the slurry

9‧‧‧ Washing water

10‧‧‧ Washing water

11‧‧‧Air supply device

12‧‧‧Air supply device

13‧‧‧Air supply device

14‧‧‧Air supply device

15‧‧‧Air supply device

20‧‧‧ glass substrate

21‧‧‧Small substrate storage deck

Claims (5)

A method for producing a polished glass substrate for a flat panel display, wherein the glass substrate is immersed in a polishing liquid containing hydrofluoric acid, and the surface is chemically polished to produce a ground glass substrate for a flat display; wherein the surface smoothing step is included The glass substrate having microcracks on the surface is immersed in a surface polishing liquid containing 40 to 90% by weight of sulfuric acid and 0.4 to 4% by weight of hydrofluoric acid and subjected to surface grinding, thereby suppressing the growth and step of the dents. Occurs to eliminate microcracking to form a smooth glass surface; and a post-grinding step of immersing the surface-smoothed glass substrate in a slurry containing 5-30% by weight of hydrofluoric acid, having a smooth glass surface In the state, the rear stage is ground to a desired substrate thickness, whereby a glass substrate having a smooth glass surface is produced without causing dents and step on the glass surface. The manufacturing method of claim 1, wherein after the surface is polished, the surface polishing liquid adhering to the surface of the glass is washed and removed, and is subjected to post-stage polishing. The manufacturing method of claim 1 or 2, wherein the surface polishing liquid is a polishing liquid containing 50 to 85% by weight of sulfuric acid and 0.5 to 4% by weight of hydrofluoric acid. The manufacturing method of claim 1 or 2, wherein the latter stage polishing liquid is a polishing liquid containing 10 to 30% by weight of hydrofluoric acid. The manufacturing method of claim 1 or 2, wherein the glass substrate is a glass substrate for a liquid crystal display.