JP5448031B2 - Etching method and etching apparatus for glass substrate - Google Patents

Description

  The present invention relates to a glass substrate etching method and an etching apparatus capable of suppressing the occurrence of defects such as scratches on a glass surface when a glass substrate used in a liquid crystal display is thinned by etching.

  In recent years, various flat panel displays such as liquid crystal displays and plasma displays have been manufactured. In this manufacturing process, a glass substrate having a substrate size of approximately 1200 × 1000 × 0.4 mm is used as a mother glass substrate, and a plurality of liquid crystal display panel substrates are formed therein. However, liquid crystal displays used for applications such as mobile devices and portable terminals have a significant need for downsizing and weight reduction, and it is generally said that the glass substrate thickness of a liquid crystal display panel required as a product is 0.2 mm or less. . Therefore, in the production of a liquid crystal display, it is necessary to thin the mother glass substrate to a desired thickness using means such as polishing.

  In general, in order to make the glass thin, it is only necessary to make a thin plate glass, but there is a limit to the production of the thin plate glass itself. Therefore, it is thinned by mechanical polishing and finished to a desired accuracy.

  The glass polishing performed for such a purpose has been conventionally performed by rough polishing with about 400 diamond grains, primary polishing with about 800 alumina grains or zirconia, or secondary with about 1200 alumina grains or zirconia. After the polishing, the final polishing is performed with 8000th cerium abrasive grains.

  Among these, three processes other than finish polishing are grinding and are shaving the glass surface. Since the glass surface is scratched and cut, a hard abrasive such as diamond, zirconia, or alumina is used as the abrasive. The final finish polishing is also called “scratch removal polishing”, and is a step of removing grinding scratches up to the previous step and making the glass surface a mirror surface.

  In the above-mentioned mechanical polishing, there is a problem such as a limit of the polishing ability in that there is a scratch or surface flaw that cannot be removed by the final polishing but remains as a crack or surface flaw. In addition, it takes a lot of man-hours, takes time, and is inefficient.

  On the other hand, in Patent Document 1 (Japanese Patent No. 2722798), a plurality of glass substrates for liquid crystal display panels are immersed in a chemical solution containing hydrofluoric acid by sealing the liquid crystal enclosing region of each element section with a sealing material. And the chemical processing method which makes thin by melt | dissolving the outer surface of a glass substrate is proposed.

  Moreover, in patent document 2 (Unexamined-Japanese-Patent No. 2003-40649), the ascending water flow of the chemical | medical solution accompanied by a bubble is generated from the bottom part of the storage tank of the chemical | medical solution containing a hydrofluoric acid, and a glass substrate is immersed in this process liquid. The outer surface of the glass substrate is melted and thinned. According to this method, since a new chemical solution is always supplied to the glass substrate surface, etching is promoted.

  However, the techniques described in Patent Document 1 and Patent Document 2 have the following problems. There are small scratches on the surface of the glass that are not visible to the naked eye. Each scratch is a groove-like or hemispherical recess, but when the glass with such a recess is etched by the method described in Patent Document 1 or Patent Document 2, the chemical solution intensively dissolves the recess, Both the width and depth of the recess become a large recess several times larger.

To deal with this problem, Patent Document 3 (Japanese Patent Laid-Open No. 2003-15111) proposes a method of removing minute defects by mechanical polishing after etching with a chemical solution is completed.
Japanese Patent No. 2722798 JP 2003-40649 A JP 2003-15111 A

  However, the method of Patent Document 3 requires two polishing steps, that is, chemical polishing and mechanical polishing, and has a problem that it leads to significant equipment restrictions and an increase in panel production cost.

  The present invention has been made to solve such problems, and provides a glass substrate etching method and a glass substrate etching apparatus capable of reducing scratches on a glass substrate for a liquid crystal display panel only by chemical polishing. The purpose is to do.

  In order to solve the above problem, a glass substrate etching method of the present invention includes a first glass substrate having a size of a plurality of liquid crystal display panels and a second glass substrate having the same size as the first glass substrate. First polishing for laminating and polishing the outer surface of at least one glass substrate of the pair of glass substrates with a chemical polishing liquid for glass substrate having a small polishing power, and bonding the glass substrates to each other via a sealing material so as to be separated from each other. And a second polishing step of thinning and polishing the thinned and polished glass substrate with a glass substrate chemical polishing liquid having a high polishing power.

  The chemical polishing liquid for glass substrate having a small polishing force used in the first polishing step is configured to comprise 5 to 10% by weight of hydrofluoric acid, 5 to 13% by weight of ammonium fluoride, and the balance of water. A thin film transistor element corresponding to a plurality of liquid crystal display panels is formed on the glass substrate, a color filter element corresponding to the plurality of liquid crystal display panels is formed on the second glass substrate, and a space between a pair of glass substrates is the seal The material is divided corresponding to each liquid crystal display panel, and after thinning and polishing the outer surface of at least one of the first and second glass substrates, the first and second glass substrates, Individual liquid crystal display panels are cut into individual pieces, or the glass substrate is polished by 30 μm ± 10 μm in the first polishing step, and the glass substrate thickness is desired in the second polishing step. It may be or is configured to be polished to a thickness.

  The glass substrate etching apparatus according to the present invention separates a first glass substrate having a size of a plurality of liquid crystal display panels and a second glass substrate having the same size as the first glass substrate from each other. A first liquid tank having a space for accommodating a pair of glass substrates bonded to each other through a sealing material, and a chemical polishing liquid for glass substrate having a small polishing power, which is put in the space; A second liquid tank having a space for accommodating a glass substrate pair to which the second glass substrate is bonded, and a chemical polishing liquid for glass substrate having a high polishing power, which is placed in the space. It is said.

  After polishing by the first liquid tank and the second liquid tank, a rinsing liquid tank for cleaning the glass substrate is provided, or for a glass substrate having a small polishing power in the first liquid tank. The chemical polishing liquid may be composed of 5 to 10% by weight of hydrofluoric acid, 5 to 13% by weight of ammonium fluoride, and the balance of water.

  The first polishing step for thinning the glass substrate is performed using a chemical polishing liquid for glass substrate having a low polishing power. As an example of a chemical polishing liquid having a small polishing power, there is a chemical polishing liquid consisting of 5 to 10% by weight of hydrofluoric acid, 5 to 13% by weight of ammonium fluoride, and the balance being water. According to the chemical polishing liquid having a small polishing power, the scratches on the glass surface are polished as follows.

  The surface of the glass is immersed in a chemical polishing liquid having a low polishing power and polishing starts. However, if there is a scratch on the glass surface, the chemical polishing liquid enters the concave portion of the scratch, and simultaneously with the glass surface, The bottom is also polished. When the chemical polishing liquid polishes the glass, the chemical polishing liquid and the glass react to form a gel-like fluoride. This fluoride covers the bottom of the recess like a film, and the contact of the new chemical polishing liquid to the glass surface is limited. At this time, if the polishing power of the chemical polishing liquid is large, chemical polishing is performed through the fluoride film, the bottom surface of the recess is polished, the recess is deep, the width is increased, and as a result, the unevenness of the glass surface is increased. turn into. However, in the present invention, since the polishing power of the chemical polishing liquid is small, the chemical polishing is greatly slowed down in the recesses such as scratches. On the other hand, the outside of the recess is a flat surface, and the glass and chemical polishing liquid react to generate fluoride as in the recess, but the fluoride is easy to move because of the flat surface, and it is separated from the glass surface and continued by the chemical polishing liquid. The glass surface can be polished. Therefore, the glass plate is polished first from the plane portion, and the concave portions such as scratches become shallower and the flatness of the glass plate is improved.

  In the state where the first polishing with the chemical polishing liquid having a small polishing power is completed, the concave portion is shallow, and the flatness of the surface of the glass substrate is improved. However, even if chemical polishing is continued as it is, polishing takes time because the polishing power is small. Therefore, next, the second polishing is performed with a chemical polishing liquid having a large polishing power (provided with a normal polishing power). In the second polishing, the thin plate is polished at a normal speed, but at the start of the second polishing, the flatness of the glass substrate is increased, so that the thin plate proceeds while maintaining this state. When the thickness is reached, the second polishing is completed. When the second polishing is completed, the glass substrate has a target thickness, and the flatness can be secured at the target value.

  A chemical polishing liquid having a low polishing power has a concentration of hydrofluoric acid of 5 to 10% by weight and ammonium fluoride of 5 to 13% by weight. However, the concentration of hydrofluoric acid exceeds 10% by weight, or fluorination. When the concentration of ammonium exceeds 13% by weight, the polishing power becomes too strong, and even if a compound is formed on the inner surface of the recess, the polishing power of the chemical polishing liquid is superior, and the inner surface of the recess is continuously polished, resulting in larger scratches. . Also, the compound accumulates at the edge of the recess, delaying only the polishing here, and forming a protrusion on the periphery of the recess.

  On the other hand, if the concentration of hydrofluoric acid in the chemical polishing solution is less than 5% by weight or the concentration of ammonium fluoride is less than 5% by weight, the polishing power is too weak and it takes too much polishing time. Become.

  When the thickness of the glass substrate is polished by 30 μm ± 10 μm in the first polishing, scratches on the surface of the glass substrate are almost eliminated. Then, even if the second polishing is performed with a chemical polishing liquid having a high polishing power, the flatness is not deteriorated, and the target flatness is maintained and the plate is thinned.

  By polishing the outer surface of a large mother glass substrate having a size of a plurality of liquid crystal panels or a liquid crystal display panel obtained by dividing the mother glass substrate with the polishing method of the present invention, the flatness necessary for the liquid crystal display panel can be obtained. It has become possible to provide a thin glass substrate having a thickness at low cost. In addition, since the flatness is increased, the display performance of the liquid crystal display panel is improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments. The composition of the chemical polishing liquid for glass substrate (hereinafter abbreviated as “chemical polishing liquid”) is expressed in wt%.

  First, a method for manufacturing a liquid crystal display panel of a mobile phone or a mobile device will be described. FIG. 1 is a process flowchart for explaining the manufacturing process. 2 is a diagram schematically showing a cross section in a state where a plurality of liquid crystal display panels are formed by bonding the first and second glass substrates, and FIG. 3 performs the first polishing and the second polishing process. It is a figure which shows the structure of a grinding | polishing apparatus typically.

  Step 101 in FIG. 1 is a step of forming thin film transistor elements 3 (array) using a well-known thin film process on the first glass substrate 1 (mother glass) shown in FIG. The first glass substrate 1 has a size corresponding to a plurality of liquid crystal display panels 7, and a thin film transistor element 3 corresponding to each liquid crystal display panel 7 performs a photolithography process including exposure, development, etching, and the like. It is formed repeatedly. Thereafter, an alignment film (not shown) is formed on the formed thin film transistor element 3, and a rubbing process for aligning liquid crystal is performed on the alignment film. On the other hand, the step 102 is a color filter forming step of forming a plurality of RGB color filter elements 4 on the second glass substrate 2 (mother glass). The color filter element 4 is formed by a well-known dye coating method or printing method.

  Next, on at least one glass substrate of the first glass substrate 1 or the second glass substrate 2, a region corresponding to each thin film transistor element 3 or color filter element 4 and forming a liquid crystal display panel, Application method using a well-known dispenser, a product seal 5 is enclosed so as to surround a space 6 in which liquid crystal is contained, and an outer peripheral seal (not shown) is provided on the outer peripheral edges of the first and second glass substrates 1 and 2. And screen printing at the same time. Here, a coating method using a dispenser was used.

  Next, in step 103, the first glass substrate 1 and the second glass substrate 2 are bonded together so that the element formation surfaces face each other as shown in FIG. In order to use the glass substrate pair 10 composed of a pair of glass substrates as a display for a mobile phone or a mobile terminal, the thickness of at least one glass substrate (1 or 2) is as thin as about 0.2 mm. It is necessary to make it.

  Step 104 is a first polishing step for reducing the thickness of the glass substrate using a chemical polishing liquid, and step 105 is a second polishing step.

  FIG. 3 is a diagram schematically illustrating a configuration of a polishing apparatus that performs the first polishing and the second polishing process. The polishing apparatus 20 includes a first liquid tank 21 and a second liquid tank 23. A rinsing liquid tank 22 containing cleaning water W therebetween and a finishing liquid tank 24 are provided. Have.

  The first liquid tank 21 is charged with a chemical polishing liquid A having a small polishing power, and is heated and cooled as both a heater for heating the chemical polishing liquid A and a cooler for cooling the chemical polishing liquid A. A device 21a is provided. The heating / cooling device 21a is a coiled hollow pipe. When heated, hot water is passed through the hollow pipe, and when cooled, cold water is passed through the hollow pipe to perform heating and cooling as necessary. Instead of the heating / cooling device 21a, a heating device and a cooling device may be provided separately.

  A stirring device 21 b is provided at the bottom of the first liquid tank 21. The stirring device 21b is a hollow pipe having a large number of holes, and when air is fed from the inlet in the direction of the arrow, air bubbles emerge from the plurality of holes and move upward so that the chemical polishing liquid can be stirred. It has become.

  The 2nd liquid tank 23 is also the same structure as the 1st liquid tank 21, and is provided with the heating cooling device 23a and the stirring apparatus 23b. The rinsing liquid tank 22 and the finishing liquid tank 24 are filled with pure water for cleaning. Pure water is always supplied with fresh water so that it can be cleaned sufficiently.

  The chemical polishing liquid A having a small polishing power in the first liquid tank 21 is composed of 5 to 10% by weight of hydrofluoric acid, 5 to 13% by weight of ammonium fluoride, and the balance being water. Desirably, hydrofluoric acid is 8 ± 1 wt% and ammonium fluoride is 10 ± 1 wt%. In the examples of the present invention, 8% by weight of hydrofluoric acid and 10% by weight of ammonium fluoride were used, and the balance was pure water. The temperature may be 25 to 50 ° C., but in the embodiment of the present invention, it is 40 ° C.

  The chemical polishing liquid B having a large polishing power in the second liquid tank 23 is usually used for polishing a glass substrate. For example, 20 wt% hydrofluoric acid and 17 wt% ammonium fluoride, The composition consists of 10% by weight acetic acid. The temperature is the same as that of the first liquid tank 21 and may be 25 to 50 ° C., but is 40 ° C. in the embodiment of the present invention.

  In the method for polishing a glass substrate of the present invention, the first polishing is performed by thinning the plurality of glass substrate pairs 10 in the first liquid tank 21 so as to be separated from each other and immersed in the chemical polishing liquid A. In this embodiment, both outer surfaces of the first glass substrate 1 and the second glass substrate 2 are polished, but thinning polishing of either the first glass substrate 1 or the second glass substrate 2 is unnecessary. In this case, a method of attaching a protective film or the like is generally performed.

  FIGS. 4A to 4C are views for explaining the first polishing performed in the first liquid tank 21 and showing the progress of polishing when a conventional chemical polishing liquid is used. A state in which the first glass substrate 1 is chemically polished using a mixed solution of 20 wt% hydrofluoric acid, 17 wt% ammonium fluoride, and 10 wt% acetic acid as a chemical polishing solution is shown. The temperature of the chemical polishing liquid was adjusted to 40 ° C. for use.

  In the first glass substrate 1 shown in FIG. 4A, the outer surface (outer surface) 1a is polished with a chemical polishing liquid. The first glass substrate 1 has a groove-like recess 1c on the surface. This is made when the first glass substrate 1 is manufactured.

  The surface 1a of the first glass substrate 1 is polished with a chemical polishing liquid, and the chemical polishing liquid also enters the recess 1c, and chemical polishing of the surface of the recess starts. Then, the chemical polishing liquid and glass react to generate a gel-like fluoride f. Conventional chemical polishing liquids have high concentrations of hydrofluoric acid and ammonium fluoride, and have high polishing power, so that a large amount of fluoride is generated. The generated fluoride f is concentrated inside the recess 1c and at the edge of the recess 1c. When fluoride f is present, the polishing of the glass is slowed down, but the conventional chemical polishing liquid has a large polishing power, and the polishing is slightly blunted on the inner surface of the recess 1c, but progresses and the depth and width of the recess 1c are increased. It will become. On the other hand, a thick fluoride f layer is formed at the edge portion of the recess 1c. The polishing is slowed by the fluoride f, and the polishing of the surrounding glass surface 1a proceeds. As a result, as shown in FIG. 4C, the protrusion 1d is formed on the periphery of the recess 1c, and the width of the recess 1c is increased and the depth is also increased.

  FIG. 5 shows an example of the present invention, in which the chemical polishing liquid A having low polishing power is 8 wt% hydrofluoric acid and 10 wt% ammonium fluoride, and does not contain hydrochloric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid, etc. Used was composed of pure water. The temperature of the chemical polishing liquid was 40 ° C.

  As shown to Fig.5 (a), the 1st glass substrate 1 has the recessed part 1c similarly to a prior art example. The chemical polishing liquid polishes the surface 1a, the chemical polishing liquid enters the recess 1c, and also polishes the surface of the recess 1c, but the fluoride f generated at this time remains in the recess 1c.

  Then, the fluoride f inhibits polishing of the bottom surface of the recess 1c. In the chemical polishing liquid of the present invention, the concentration of hydrofluoric acid and ammonium fluoride is lower than that of the conventional one. Therefore, the polishing suppression force by the fluoride f is stronger than the polishing power of the chemical polishing liquid, and the bottom surface of the recess 1c is almost polished. Do not become deep. On the other hand, since the polishing of the surface 1a proceeds, the recess 1c becomes shallow as shown in FIG. 5C, and finally becomes a very shallow depression 1c as shown in FIG. 5D. . In other words, the surface of the first glass substrate 1 is reduced in unevenness and approaches flat.

  In addition, although the 1st glass substrate 1 was illustrated in FIG. 4, FIG. 5, it cannot be overemphasized that the 2nd glass substrate 2 is also the same. Moreover, although the thing resulting from a damage | wound was illustrated as the recessed part 1c, it is the same also in the recessed part by other than that, for example, a bubble.

  4 and 5, the chemical polishing liquid having a high concentration of hydrofluoric acid or ammonium fluoride has too strong polishing power and does not become flat. On the contrary, if the concentration of hydrofluoric acid or ammonium fluoride is low, the polishing is performed. It turns out that the power is too low and it takes time to polish.

  As a result of further diligent efforts, the inventor of the present application has a concentration of hydrofluoric acid in the range of 5 to 10% by weight and a concentration of ammonium fluoride in the range of 5 to 13% by weight as the chemical polishing liquid A having a low polishing power. I knew it would be good. A more desirable range is 7 to 9% by weight of hydrofluoric acid and 9 to 11% by weight of ammonium fluoride. In either case, the remaining part was water and pure water was used.

  According to the conventional glass polishing using a chemical polishing liquid, if a minute scratch is present on the surface of the glass substrate, the scratch is enlarged and the function as a liquid crystal display panel is impaired. Therefore, it is desirable that the chemical polishing liquid to be used not only can suppress the expansion of scratches but also has a characteristic that can maintain the flatness of the entire glass substrate surface. Needless to say, the sealing performance of the sealing material is not adversely affected.

When the first polishing is performed in the first liquid tank 21 and the surfaces of the glass substrates 1 and 2 are polished by about 30 μm, the scratches on the surfaces of the glass substrates 1 and 2 are almost flattened, so the first polishing is finished. To do. The glass substrate pair 10 is pulled up from the first liquid tank 21 and put in the liquid tank 22 for rinsing, and is washed with pure water . By this cleaning, the chemical polishing liquid A and the fluoride f generated by the chemical polishing are washed away.

  When the cleaning is finished, the glass substrate pair 10 is placed in the second liquid tank 23 and immersed in the chemical polishing liquid B, and the thinned second polishing in Step 105 is started. The chemical polishing liquid B has the above-described composition and has a normal polishing force, and polishes the surfaces of the glass substrates 1 and 2 at the same speed as the conventional one to make a thin plate. The temperature of the chemical polishing liquid B is maintained at 40 ° C. by the heating / cooling device 23a, and polishing proceeds while stirring the chemical polishing liquid B by the stirring device 23b. The chemical polishing liquid B has the above-described composition and high polishing power. However, since the unevenness of the glass substrate 1 is reduced by the thinned first polishing, the chemical polishing is performed while maintaining the flat state as it is.

  When the thickness of the glass substrate 1 reaches a desired thickness by the thinning second polishing, the second polishing is finished. The glass substrate pair 10 is pulled up and washed with pure water in the finishing bath 24.

  In the subsequent 106 steps, the pair of mother glass substrates bonded together are cut in the middle of the product seals 5 and 5 shown in the center of FIG. 2 to form one liquid crystal display panel 7 having a predetermined display area. This is a singulation cutting process. The glass substrate was cut by combining a scribe cutting method using a cutter wheel and a break cutting method for dividing the glass substrate.

In step 107, after the liquid crystal is sealed in the region surrounded by the product seal 5 described above, the sealing port is sealed.

  Finally, step 108 is a step of attaching a polarizing plate to the surface of the liquid crystal display panel substrate described above, whereby the liquid crystal display panel 10 is completed.

  By the way, in the manufacturing process of the above-mentioned liquid crystal display panel, the pair of glass substrates (1 or 2) bonded together in the state of mother glass was thinned and polished in the state of mother glass. However, liquid crystal is sealed in a region enclosed by the product seal 5 in advance by a dropping method, the order of the 106 step and the 104 step is changed, and the liquid crystal display panel having a predetermined size is cut into pieces and then at least one of them is cut. The surface of the glass substrate may be thinned and polished.

  FIG. 6 is an experimental example comparing the polishing with the conventional chemical polishing solution B and the first chemical polishing solution A (hydrofluoric acid 8 wt%, ammonium fluoride 10 wt%). A concave indentation 1c was artificially formed by pressing a diamond indenter having a quadrangular pyramid of a micro Vickers hardness tester on a glass substrate serving as a test piece with three loads of 2N, 3N, and 5N. The vertical axis is the diameter of the recess (the length of the diagonal because it is a square), and the horizontal axis is the weight of the indenter. In FIG. 6, the square points are the diameters of the recesses (the length of the diagonal lines) by the diamond indenter. Triangular points are the above-described conventional chemical polishing liquid, and circles are the above-described chemical polishing liquid of the present invention.

  According to FIG. 6, the chemical polishing liquid of the present invention has a recess having a diameter of 5 μm smaller than that of the conventional chemical polishing liquid. In addition, in the conventional chemical polishing liquid, the diameter is larger than the concave portion formed with the diamond indenter, whereas in the chemical polishing liquid of the present invention, the diameter after polishing is smaller than the concave portion formed with the diamond indenter. I understand that

It is a flowchart which shows the manufacturing process of the liquid crystal display panel explaining embodiment of this invention. It is the figure which showed typically the cross section of the state which bonded together the 1st and 2nd glass substrate and formed the several liquid crystal display panel. It is a figure which shows typically the structure of the grinding | polishing apparatus which performs a 1st grinding | polishing and a 2nd grinding | polishing process. It is a figure explaining the state of the 1st grinding | polishing of the glass substrate by the conventional chemical polishing liquid. It is a figure explaining the state of the 1st grinding | polishing of the glass substrate by the chemical polishing liquid of this invention. It is a diagram which shows the grinding | polishing state of the recessed part by the conventional chemical polishing liquid and the chemical polishing of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st glass substrate 1c Recess 1d Protrusion 2 2nd glass substrate 3 Thin film transistor element 5 Product seal 6 Space 7 Liquid crystal display panel 10 Glass substrate pair 21 1st liquid tank 23 2nd liquid tank A Chemical with small polishing power Polishing liquid B Chemical polishing liquid with high polishing power

Claims (5)

The first glass substrate on which a plurality of liquid crystal display panels are formed and the second glass substrate having the same size as the first glass substrate are bonded together via a sealing material so as to be separated from each other, The outer surface of at least one glass substrate of the pair of glass substrates is thinned with a chemical polishing liquid for glass substrate comprising a first polishing step and a second polishing step, and the first polishing step is more abrasive than the second polishing step. is rather small, the first polishing force small glass substrates for chemical polishing solution used for polishing step, hydrofluoric acid 5-10% and 5-13% by weight of ammonium fluoride, in a configuration where the residual is composed of water, Etching the glass substrate characterized by polishing and flattening scratches on the surface of the glass substrate to be polished by the first polishing step, and polishing the glass substrate to a desired thickness by the second polishing step. Method A thin film transistor element corresponding to a plurality of liquid crystal display panels is formed on the first glass substrate, a color filter element corresponding to the plurality of liquid crystal display panels is formed on the second glass substrate, and a space between the pair of glass substrates Are divided corresponding to each liquid crystal display panel by the sealing material, and after thinning and polishing the outer surface of at least one of the first and second glass substrates, the first and second glasses The method for etching a glass substrate according to claim 1, wherein the substrate is cut into individual liquid crystal display panels. In the first polishing step, the thickness of the glass substrate was 30 [mu] m ± 10 [mu] m polishing, according to claim 1 or 2 the thickness of the glass substrate at the second polishing step, characterized in that the polished until a desired thickness The glass substrate etching method as described in 2. A glass in which a first glass substrate having a size of a plurality of liquid crystal display panels and a second glass substrate having the same size as the first glass substrate are bonded to each other via a sealing material so as to be separated from each other. A first liquid tank having a space for accommodating a pair of substrates, and a chemical polishing liquid for a glass substrate having a small polishing power, which is placed in the space; and glass in which the first and second glass substrates are bonded together possess a space for accommodating the substrate pair, a second liquid tank having a large glass substrate for chemical polishing solution of the polishing force is placed in the space, a polishing force in the first liquid tank A small chemical polishing solution for a glass substrate is composed of 5 to 10% by weight of hydrofluoric acid, 5 to 13% by weight of ammonium fluoride, and the balance is water, and the surface of the glass substrate polished in the first liquid tank The scratches are polished and flattened, and the thickness of the glass substrate is increased by the second liquid tank. Etching apparatus for a glass substrate, which comprises grinding to a desired thickness. The etching apparatus according to claim 4, further comprising a rinsing liquid tank for cleaning the glass substrate after polishing by the first liquid tank and the second liquid tank.

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