JP5671436B2 - Manufacturing method of glass substrate - Google Patents

Description

  The present invention relates to a method for producing a glass substrate produced by forming a hole in a glass substrate.

  In recent years, with the spread of mobile electronic devices, it has become important to improve display performance. Glass substrates for cover glasses used in touch panels such as smartphones and tablet terminals are used to reduce the weight and size of mobile terminals. There is a need for thin glass. Accordingly, a glass having a stronger strength is demanded. On the other hand, in order to install a speaker, an input key, or the like on the display surface, it may be necessary to make a hole in the cover glass. In such a case, depending on the processing method, fine flaws and cracks may occur on the inner wall of the hole, which may reduce the strength of the cover glass.

  As a method for forming a hole in a glass substrate, a method of performing a hole forming process by a method such as a sandblasting method or an etching method after performing a resist layer patterning step by a photolithography method is generally known. In the resist layer patterning process by the photolithographic method, a resist layer made of a photocrosslinkable resin is formed on a glass substrate, and then the resist layer is exposed and developed, which corresponds to the drilling position of the glass substrate. The resist layer is patterned on the glass substrate by selectively removing a portion of the resist layer to be formed. In the subsequent hole forming step, only the glass substrate of the portion from which the resist layer has been removed can be punched into the glass substrate by being subjected to sandblasting or etching. In the method for forming a hole in a glass substrate by the sand blast method, a hole is formed in the glass substrate by spraying a powder of a material such as SiC or alumina called an abrasive on the glass substrate. In addition, in the method for forming holes in a glass substrate by an etching method, holes are formed in the glass substrate by melting the glass using a treatment liquid containing a corrosive substance such as hydrogen fluoride or ammonium fluoride.

  An example of processing glass using the sand blast method is shown in Patent Document 1, and here, a method for forming a recess for accommodating an organic EL element in a glass substrate is described. The law is used. In the sand blasting method, the abrasive is physically collided with the surface of the glass substrate to form the vertical holes, so that fine cracks are likely to occur on the inner walls of the vertical holes, thereby reducing the strength of the glass substrate.

  In order to solve such a problem, there is a case where a technique for suppressing the occurrence of fine cracks is taken by changing the abrasive particles used in the sandblasting method to smaller ones. However, in this case, broken pieces of glass generated by sandblasting are very small, and thus it is difficult to remove them by washing, which may deteriorate productivity.

  Patent Document 2 describes a glass etching treatment method using an ultraviolet curable resist composition for glass etching. In the processing of the glass substrate by the etching method, fine scratches and cracks due to a physical impact, which is a problem in the processing by the sandblast method, do not occur. However, since a longer time is required for processing as compared with the sandblasting method, productivity is poor, and there is a problem that an etching operation requiring a deep drilling process is difficult.

Smooth as glass substrate manufacturing method to solve these problems, Patent Document 3, by performing an etching process after the sandblasting, fine cracks occurred on the inner wall of the hole by the sandblast treatment by etching Thus, a method for producing a glass substrate is disclosed in which it is possible to produce a glass substrate with very few fine cracks on the inner wall of the hole. However, this method has a problem that a hydrofluoric acid-resistant oxide film must be formed on the surface of the glass substrate, the process is complicated, and productivity is deteriorated.

Japanese Patent Laid-Open No. 2005-50596 JP 2007-128052 A JP 2007-145656 A

  It is an object of the present invention to produce a glass substrate having no fine cracks on the inner wall of a hole with high productivity in a method for producing a glass substrate including a step of forming a hole in a glass substrate using a sandblasting method and an etching method. It is in providing the manufacturing method of a glass substrate.

As a result of intensive studies to solve the above problems, a step of forming a resin layer on at least one surface of a glass substrate, a step of exposing and developing the resin layer, a step of forming a hole in the glass by sandblasting, a resin layer It has been found that the above-mentioned problems can be solved by a method for producing a glass substrate, which comprises a step of heating the substrate to advance crosslinking and a step of etching treatment in this order.

  According to the glass substrate manufacturing method of the present invention, in the glass substrate manufacturing method including the glass substrate hole forming step using the sand blasting method and the etching method, a glass substrate having no fine cracks on the inner wall of the hole is obtained with high productivity. A method for manufacturing a glass substrate that can be manufactured can be provided.

  Hereinafter, the production method of the glass substrate of the present invention will be described in detail.

  A resin layer is formed on at least one side of a glass substrate that has been subjected to pretreatment such as alkali degreasing and washing with an organic solvent. For the formation of the resin layer, for example, a thermocompression laminator apparatus that presses and presses a rubber roll heated to 100 ° C. or higher can be used. After the resin layer is formed, the carrier film of the resin layer is peeled off, exposure and development are performed to form a pattern of the resin layer, and then the glass base part not covered with the resin layer is formed by sandblasting. By removing, a hole is formed in the glass substrate. Thereafter, the resin layer is heated, and subsequently, the inner walls of the holes are smoothed by etching the inside of the holes formed in the glass substrate by an etching process, thereby producing a glass substrate having very few fine cracks.

  The glass substrate according to the present invention can be applied regardless of the glass composition, and for example, silica glass, soda lime silica glass, lead glass, borosilicate glass, aluminosilicate glass and the like can be used.

  As the resin layer according to the present invention, the light irradiation part is cross-linked and insolubilized in the developing solution, and is resistant to the sand blasting process, and the resin layer after the sand blasting process is resistant to the etching process by heat treatment. Examples include negative dry film resists having characteristics. As a method of imparting resistance to sandblasting, it is known that it is effective to give rubber elasticity to the resin layer after photocrosslinking, and urethane (meth) acrylate oligomer is added as a component of the dry film resist. Is common. Further, as a method for imparting etching resistance to the resin layer, there is a method of improving water resistance by advancing crosslinking of the resin layer and preventing penetration of the etching solution. In the case of a general negative type dry film resist, unreacted crosslinkable components remain in the resin layer only by light irradiation for the purpose of patterning. Therefore, crosslinking is performed by performing additional exposure or heating after patterning. Can be advanced. Furthermore, since the adhesiveness between the resin layer and the glass substrate can be improved in the heat treatment, further etching resistance can be imparted thereby. The dry film resist includes, for example, a binder polymer containing a carboxyl group, a urethane (meth) acrylate oligomer, a photopolymerizable compound having at least one polymerizable ethylenically unsaturated group in the molecule, a photopolymerization initiator, a solvent, In addition, a resin layer composed of other additives is coated on a carrier film such as polyester and, in some cases, is covered with a protective film such as polyethylene. Their blending ratio is determined by a balance of required properties such as sensitivity, resolution, degree of cross-linking and tenting property. Examples of dry film resist formulations are “Photopolymer Handbook” (edited by Photopolymer Social Society, published in 1989, published by Kogyo Kenkyukai Co., Ltd.) and “Photopolymer Technology” (edited by Yamamoto Ao, Nagamatsu Mototaro, published in 1988, Nikkan Kogyo Shimbun) and the like, and a desired composition can be used. The thickness of the dry film resist is preferably 20 to 100 μm, and more preferably 50 to 100 μm. If the thickness is less than 20 μm, the etching solution may pass through the resin layer while penetrating the resin layer, so that the portion that does not need the etching treatment may be processed. On the other hand, when the thickness exceeds 100 μm, the time required for the sandblasting and etching treatment becomes long, and the productivity may deteriorate.

  The resin layer exposure method according to the present invention includes a xenon lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a reflection image exposure using a UV fluorescent lamp as a light source, a single-sided, double-sided contact exposure using a photo tool, and proximity. Examples include a method, a projection method, and laser scanning exposure. When performing scanning exposure, a laser light source such as a He—Ne laser, He—Cd laser, argon laser, krypton ion laser, ruby laser, YAG laser, nitrogen laser, dye laser, or excimer laser is used according to the emission wavelength. The exposure can be performed by wavelength conversion and scanning exposure, or by scanning exposure using a liquid crystal shutter and a micromirror array shutter.

  As a developing method according to the present invention, a developer corresponding to the photocrosslinkable resin layer to be used is used, and a glass substrate is sprayed toward the surface on which the resin layer is formed to remove unnecessary portions as a resist pattern. Then, a resist layer for the sandblast treatment is formed. In general, a 1% by weight aqueous sodium carbonate solution is used.

  As a sandblasting method according to the present invention, an abrasive material suitable for a glass base material used for compressed air by a compressor or the like is mixed, and then sprayed toward the surface of the glass base material on which the resin layer is formed. Drill a hole in the glass that is not covered by the layer. As the material for the abrasive, alumina, SiC, garnet, zircon, glass, iron, and stainless steel can be used. Further, the abrasive used in the sandblasting method preferably has a maximum particle size of 20 to 150 μm, and more preferably 20 to 100 μm. If the maximum particle size of the abrasive is smaller than 20 μm, the time for forming holes in the glass substrate becomes long, and the productivity may deteriorate. On the other hand, when the maximum particle size of the abrasive is larger than 150 μm, the surface roughness of the surface subjected to the sandblast treatment becomes large, the time required for the etching treatment becomes long, and the productivity may be deteriorated. It is also possible to change to an abrasive having a different maximum particle size during the sandblasting process.

  As a method for heating the resin layer in the present invention, the glass substrate after sandblasting treatment is put into a heating device such as a blower dryer, and heated at about 100 to 180 ° C. for about 15 to 60 minutes. When the heating temperature is lower than 100 ° C., the time required for heating becomes long and the productivity may deteriorate. In addition, when the heating temperature exceeds 180 ° C., the resin layer may be deformed depending on the structure of the resin layer, and the resin layer covers a portion that needs to be etched by this deformation, which may cause etching failure. There is a case.

  As an etching method according to the present invention, an inner wall of a hole formed in a glass base material is sprayed using an etching solution suitable for the glass base material to be used and sprayed toward the surface of the glass base material on which the resin layer is formed. Is dissolved so that there are very few fine cracks. The etching solution is not particularly limited as long as it can dissolve and remove glass. Specific examples thereof include hydrofluoric acid aqueous solutions such as hydrofluoric acid and silicohydrofluoric acid, and aqueous solutions obtained by mixing sulfuric acid, nitric acid, and hydrochloric acid with these aqueous solutions. It can be used as a treatment liquid. The hydrofluoric acid content in the etching solution is preferably 1 to 20%. When the hydrofluoric acid content is less than 1%, etching takes a long time, and productivity may deteriorate. If the hydrofluoric acid content is higher than 20%, the etching rate becomes too fast, and it may be difficult to perform uniform etching. In addition, the hydrofluoric acid content is high so that it is safe to handle. Sexuality may be a problem. Although the etching treatment conditions depend on the depth and diameter of the holes formed in the glass substrate, for example, the etching treatment can be performed by spraying an etching treatment solution at 5 to 50 ° C. for 0.5 to 5 minutes.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example.

(Example)
A glass substrate of area 100 × 100 mm, thickness 1.1 mm, non-alkali aluminoborosilicate glass was washed with acetone, and dry film resist (Mitsubishi Paper Co., Ltd., trade name: MS7100) using a laminator for dry film resist. , Thickness: 100 μm) was thermocompression bonded to form a resin layer.

  Next, contact exposure was performed using an exposure original photomask having a circular image having a diameter of 300 μm. Subsequently, development was performed using a 1% by mass aqueous sodium carbonate solution (liquid temperature 30 ° C., spray pressure 0.15 MPa) to form a resist layer.

  Next, the substrate on which the resist layer is formed is subjected to a sand blast treatment (spray pressure: 0. 5 minutes) using an SiC abrasive (manufactured by Naniwa Polishing Co., Ltd., trade name: GC fine powder # 320, maximum particle size: 98 μm). 2 MPa) was performed to form holes in the glass substrate.

  Next, the glass substrate in which the holes were formed was subjected to heat treatment at 150 ° C. for 10 minutes with a sending dryer, and the resin layer was heated.

  Next, the glass substrate was etched for 2 minutes using an etching treatment liquid (aqueous solution having a hydrofluoric acid concentration of 7 mass% and a sulfuric acid concentration of 15 mass%, liquid temperature: 40 ° C., spray pressure 0.15 MPa).

  As a result of observing the inside of the hole of the obtained glass substrate with a scanning electron microscope, it was confirmed that holes with an average depth of 300 μm were formed in the glass substrate, and there were almost no microcracks on the inner wall of the hole. Confirmed not.

(Comparative Example 1)
A glass substrate was produced in the same manner as in Example except that the etching treatment was not performed, and the inside of the hole of the obtained glass substrate was observed with a scanning electron microscope. As a result, it was confirmed that innumerable fine scratches and cracks existed. In such a state, the strength of the glass substrate is significantly reduced.

(Comparative Example 2)
A glass substrate was produced in the same manner as in the examples except that the sandblast treatment was not performed and the etching time was set to 100 minutes, and the inside of the hole in the obtained glass substrate was observed with a scanning electron microscope. It was confirmed that holes with an average depth of 300 μm were formed in the base material, and it was confirmed that there were almost no microcracks on the inner walls of the holes. However, in the method of Comparative Example 2, since the processing time of the drilling process takes four times or more as compared with the Example, productivity becomes worse in such a method.

  The present invention is widely used for manufacturing a glass substrate produced by forming holes in a glass substrate. For example, it can be used as a method for manufacturing a glass substrate that can be used for a protective panel of an electronic device such as a smartphone, a tablet terminal, a PDA, a car navigation device, a digital camera, a digital video camera, or a game machine.

Claims (1)

A step of forming a resin layer on at least one surface of a glass substrate, a step of exposing and developing the resin layer, a step of forming a hole in the glass by sandblasting, a step of heating the resin layer to advance crosslinking , an etching treatment The manufacturing method of the glass substrate characterized by including the process to perform in this order.