KR101151672B1 - Fabrication Method of Strengthened Glass Substrate - Google Patents

Abstract

In the method of manufacturing a tempered glass substrate according to the present invention, after forming a laminate of a glass substrate and an aluminum film, the aluminum film is used as an anode, and the glass substrate and the aluminum film are anodized to improve the strength of the glass substrate. There is a characteristic.
In the method of manufacturing tempered glass according to the present invention, aluminum ions can be infiltrated in a short time by diffusing aluminum ions by the electrical driving force of the anode junction rather than chemical driving force, and infiltration of aluminum ions and surface defects present on the surface of the glass substrate ( The strength of the glass substrate is increased by the healing of flaw), and the glass is strengthened at a very low temperature in a short time regardless of the composition of the glass, and in order to mass produce a large area of tempered glass substrate in a short time. There is a suitable advantage.

Description

Fabrication Method of Strengthened Glass Substrate

The present invention relates to a method of manufacturing a tempered glass substrate, and to a method of manufacturing a tempered glass substrate that can be used in the package of a digital camera, a display device, a solar cell, a portable terminal, a semiconductor device.

In today's electronics that pursue high performance, ultra small / high density, low power, multifunction, ultra-fast signal processing, and permanent reliability, ultra-small package components are essential components for computers, telecommunications, mobile communications, and high-end consumer electronics. Increasingly, display devices such as LCDs and PDPs, digital cameras, computers, mobile phones, and communication systems are being expanded.

As the miniaturization of electronic devices is progressing, glass substrates used in packaging, electronic devices, solar cells, displays, etc. are also becoming thinner. Therefore, in order to improve the reliability and durability of products, it is increasingly important to improve the mechanical strength of glass substrates. It is becoming.

The actual strength of the glass is only 1% to 0.1% of the theoretical strength, due to the physical defects that inevitably exist on the glass surface. The breakage of the glass substrate occurs mainly when tensile stress is applied to the surface, and the stress is concentrated on the physical defects on the surface, which acts as a source of cracking, and the cracks generated at the defect sites are not accompanied by plastic deformation. It spreads quickly and causes brittle destruction.

In general, in order to enhance the strength of glass, a method of introducing a compressive stress to the surface has been used, and a method of introducing a compressive stress to the surface by a physical / chemical method has been mainly studied and used.

The physical method for the introduction of surface compressive stress is to heat the glass to a temperature between an annealing point (approximately 390 ° C for soft glass) and a softening point (approximately 620 ° C for soft glass). After making it uniform, the surface is quenched so that a rapid temperature gradient is formed on the surface and the inside of the glass to make the surface area open, and the slow cooled inner area is made a dense structure to form a compressive stress on the surface. When the glass is strengthened by this physical method, the strength of the glass is strengthened by the amount of the compressive stress introduced, as the breaking stress must be applied to the surface to overcome the compressive stress introduced to the surface.

A chemical method for introducing surface compressive stress is to use ion exchange characteristics, and to exchange the alkali ions present in the glass with ions having a larger ion radius, thereby causing the compressive stress on the glass surface due to the difference in the occupied volume of the ions. to be. Ion exchange causes the glass to contact the molten salt of the ions to be exchanged to diffuse the ions contained in the molten salt into the glass. This chemical strengthening is due to the diffusion of alkali ions and the difference in the occupied volume of the ions has a disadvantage that the compressive stress is smaller than the physical strengthening method and the compressive stress is generated only in a limited region near the surface. In addition, in order to introduce sufficient compressive stress using chemical strengthening, ion exchange must be performed for a long time, and the temperature of the ion exchange liquid needs to be increased.

Conventional physical strengthening and chemical strengthening are both limited to be performed at a high temperature of 400 ° C. or higher, and surface defects, which are the root cause of lowering the strength of glass, still exist, and models for optimal strengthening according to the type of glass are used. It has to be newly made, and the characteristics are very sensitive to changes in process conditions such as physical strengthening, or the strengthening process must be performed for a long time such as chemical strengthening.

An object of the present invention for solving the above problems is to provide a method that can increase the strength of the glass in a short time at a very low temperature below the annealing point irrespective of the type of glass, the strength of the glass It is to provide a way to increase the strength of the glass by removing the surface defects present on the glass surface, which is the underlying cause of the degradation.

Method (I) of manufacturing a tempered glass substrate according to the present invention comprises the steps of: a1) vacuum pressing the glass substrate and the aluminum film; b) anodically bonding the glass substrate and the aluminum film with an electrode positioned to face the aluminum film with the glass substrate therebetween as a cathode and the aluminum film as an anode; And c) dissolving and removing the anodized aluminum film; There is a feature performed, including.

Method (II) of manufacturing a tempered glass substrate according to the present invention comprises the steps of: a2) depositing aluminum on a glass substrate to form a transparent aluminum film; And b) anodically bonding the glass substrate and the aluminum film with the electrode positioned to face the aluminum film with the glass substrate therebetween as a cathode and the aluminum film as an anode. There is this.

Unlike the manufacturing method (I), the method (II) of the tempered glass substrate is characterized in that the thickness of the aluminum film in step a2) is 10 to 30 nm, and the aluminum film present on the glass substrate after the anodic bonding in step b) There is a feature that is not removed.

In the manufacturing method (I and II) of the tempered glass substrate, the defects present on the surface of the glass substrate are removed by the anodic bonding, and the aluminum ions of the aluminum film are diffused by the electric force to the glass substrate. Thereby, by this, the bending strength of the glass substrate is characterized by increasing 30 to 50%.

In the manufacturing method (I and II) of the tempered glass substrate, the anodic bonding in step b) is characterized in that it is carried out at a very low temperature of 250 to 300 ℃, the maximum value of the voltage applied during the anodic bonding in step b) Is characterized by being 800 to 1000V.

In the manufacturing method (I and II) of the tempered glass substrate, when the anodic bonding of the step b), the multi-stage step-up is carried out to be sequentially stepped up to 8 to 12 times at regular intervals up to the maximum value of the voltage, The time interval at which the multi-stage boosting is performed is preferably 3 minutes to 10 minutes.

In the method of manufacturing tempered glass according to the present invention, aluminum ions can be infiltrated in a short time by diffusing aluminum ions by the electrical driving force of the anode junction rather than chemical driving force, and infiltration of aluminum ions and surface defects present on the surface of the glass substrate ( The strength of the glass substrate is increased by the healing of flaw), and the glass is strengthened at a very low temperature in a short time regardless of the composition of the glass, and in order to mass produce a large area of tempered glass substrate in a short time. There is a suitable advantage.

1 is an example showing a process diagram of a tempered glass manufacturing method (I) according to the present invention,
Figure 2 is an example showing a process diagram of the tempered glass manufacturing method (II) according to the present invention,
Figure 3 is an example showing a cross-sectional view of the tempered glass produced by the manufacturing method according to the invention, Figure 3 (a) is a cross-sectional view of the tempered glass produced by the tempered glass manufacturing method (I), Figure 3 (b ) Is a cross-sectional view of the tempered glass manufactured by the tempered glass manufacturing method (II),
4 is a view showing an example of a multi-stage step-up profile performed in the anode bonding process of the manufacturing method (I and II) according to the present invention,
5 is a high magnification scanning electron microscope (HR-TEM) photograph of the interface between the aluminum film and the glass substrate after the anodic bonding.
6 is a view showing the bending test results of the tempered glass substrate manufactured according to the present invention.
Description of the Related Art [0002]
100: glass substrate with surface defects
210, 220: aluminum membrane
300: glass substrate after anodization
230: aluminum film after anodization

Hereinafter, a manufacturing method of the present invention will be described in detail with reference to the accompanying drawings. The drawings introduced below are provided by way of example so that the spirit of the invention to those skilled in the art can fully convey. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms, and the following drawings may be exaggerated in order to clarify the spirit of the present invention. For example, the surface defects present in the glass substrate in the drawings presented below mainly refer to very fine defects of several nanometers order, but are exaggerated for clarity of understanding. Also, throughout the specification, like reference numerals designate like elements.

Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

FIG. 1 is an example showing a process diagram of a method (I) for manufacturing tempered glass according to a first aspect of the present invention. As shown in FIG. 1, one surface of a glass substrate 100 having a surface flaw exists. After aligning the aluminum film (foil, 210) in the position, it is compressed to produce a laminate in which the aluminum film 210 and the glass substrate 100 are laminated.

Lamination of the aluminum film 210 and the glass substrate 100 using vacuum pressing in terms of processing a large area glass substrate, high adhesion between the glass substrate and the aluminum film, and good contact with the aluminum film at the surface defect site. It is preferable to manufacture a sieve, and in detail, the container in which the glass substrate 100 is placed is made into a vacuum state, and the aluminum film 210 is expanded to the glass substrate 100 by contact with the glass substrate 100 by applying a vacuum pressure. The glass substrate 100 and the aluminum film 210 are pressed.

In this case, the aluminum film 210 to be vacuum-compressed is preferably an aluminum foil, and the thickness of the aluminum foil is not particularly limited, but is substantially 2 to 10 μm.

After manufacturing the laminate in which the aluminum film 210 and the glass substrate 100 are laminated by vacuum pressing, the vacuum pressing is performed with the aluminum film 210 of the laminate as the anode and the glass substrate 100 interposed therebetween. An anode bonding is performed by using the electrode positioned to face the aluminum film 210 as the cathode.

In detail, during the anodic bonding, a positive voltage is applied to the aluminum film 210, and a negative voltage including ground is applied to an electrode disposed on an opposite surface of the glass substrate 100 on which the aluminum film 210 is formed. Is applied. An electric field is formed in the laminate in which the aluminum film 210 and the glass substrate 100 are stacked by the anodic bonding, and aluminum ions present in the aluminum film 210 are formed by the electric force. At the same time as the diffusion to the substrate 100, defects existing on the surface of the glass substrate 100 are healed, thereby increasing the strength of the glass substrate 100.

As described above, in the method of manufacturing tempered glass according to the present invention, as aluminum ions are diffused into the glass substrate 100 by the electric driving force rather than the simple chemical driving force or the thermal driving force, the voltage applied during the anode bonding is increased. The amount of aluminum ions flowing into the glass substrate 100 and the glass of aluminum ions flowing into the glass substrate are adjusted by adjusting factors selected from the size, the profile of the voltage applied during the anodic bonding and the time at which the anodic bonding is performed. The ion concentration profile according to the substrate thickness and the depth of the aluminum ion is introduced into the glass substrate is controlled, and the glass substrate is strengthened at a low temperature in a relatively short time.

After the anodic bonding is performed, the aluminum film 210 present on the glass substrate 300 on which the aluminum ions are diffused and the surface bonding is healed is removed by wet etching. The etchant used during the wet etching may be performed using a conventional etchant that selectively dissolves only the aluminum film. For example, the wet solution of the aluminum film 210 using nitric acid, acetic acid, phosphoric acid, or a mixed acid thereof may be used. Etching may be performed. After the aluminum film 210 is removed by the wet etching, the glass substrate 300 on which the anodic bonding is performed may be washed.

FIG. 2 is an example of a process diagram of a method (II) of manufacturing tempered glass according to a second aspect of the present invention. As shown in FIG. 2, one surface of a glass substrate 100 having surface flaws exists. Aluminum is deposited on to form a transparent aluminum film 220.

The deposition of the aluminum may be deposition by heat, ion beam or laser evaporation (evaporation) or deposition using a sputter, in the tempered glass manufacturing method (II) according to the second aspect of the present invention, the aluminum When the deposition of the, it is characterized in that the transparent aluminum film 220 is formed by adjusting the deposition thickness of aluminum.

The thickness of the aluminum film 220 formed by the deposition in order to perform the role of an electrode having excellent electrical conductivity during anodic bonding without lowering the transparency of the glass substrate 100 by the deposition of aluminum is 10 to 30nm It is preferable.

After depositing aluminum on the glass substrate 100 to manufacture a laminate in which the transparent aluminum film 220 and the glass substrate 100 are laminated, anodization is performed similarly to the above-described manufacturing method (I).

In detail, after manufacturing a laminate in which the transparent aluminum film 220 and the glass substrate 100 are laminated by vapor deposition, the transparent aluminum film 220 of the laminate is used as an anode, and the glass substrate 100 is interposed therebetween. An anode bonding is performed by using the electrode positioned to face the transparent aluminum film 220 as a cathode. A positive voltage is applied to the transparent aluminum film 220, and a negative voltage including a ground is applied to an electrode disposed on an opposite surface of the glass substrate 100 on which the aluminum film 220 is formed.

An electric field is formed in the laminate in which the transparent aluminum film 220 and the glass substrate 100 are stacked by the anodic bonding, and aluminum ions present in the transparent aluminum film 220 are formed by electric force. At the same time, the glass substrate 100 diffuses into the glass substrate 100 and a flaw on the surface of the glass substrate 100 is healed to increase the strength of the glass substrate 100.

Unlike the manufacturing method (I) using vacuum compression of aluminum foil, in the manufacturing method (II) according to the second aspect of the present invention, the transparent aluminum film is not removed after the anode bonding, and the anode bonded transparent The laminate of the aluminum film 230 and the glass substrate 300 in which the aluminum ions are diffused is characterized in that the tempered glass to be manufactured.

3 is a cross-sectional view of the tempered glass produced according to the present invention, Figure 3 (a) is an example of a cross-sectional view of the tempered glass according to the first aspect of the present invention, Figure 3 (b) of the present invention It is an example of sectional drawing of the tempered glass which concerns on a 2nd aspect.

3 (a) and 3 (b) the tempered glass produced by the manufacturing method (I or II) of the present invention is in contact with the aluminum film (210 or 220) to the surface of the glass substrate 100, the anode bonding is performed Shading gradually softening as a reference is an example showing the concentration of aluminum ions introduced into the glass substrate 100 by an anode bonding.

As shown in FIG. 3 (a) according to the first aspect of removing the aluminum film by wet etching and FIG. 3 (b) according to the second aspect in which the tempered glass having the transparent aluminum film laminated is manufactured, the manufacturing method of the present invention. Aluminum ions are introduced into the glass substrate 100 by electrical force (I or II), and compressive stress is formed in a predetermined region of the glass substrate by aluminum ions, and surprisingly, the glass before the anodic bonding of FIGS. Surface defects present in the substrate 100 were removed by anod bonding with the aluminum film, so that the bending strength of the glass substrate 100 was increased by 30 to 50% compared to before the treatment of the present invention.

Hereinafter, based on FIG. 4, the preferable example of the positive electrode bonding performed by the manufacturing method (I or II) of this invention is explained in full detail.

In the anode bonding performed in the manufacturing method of the present invention, the maximum value of the voltage applied during the anode bonding of step b) is 800 to 1000V. The maximum value of the voltage applied during the anodic bonding not only affects the amount of aluminum ions flowing into the glass substrate and the penetration depth of aluminum ions, but also affects whether or not the defects present on the surface of the glass substrate are removed. Crazy

In addition, the anodic bonding performed in the production method of the present invention is characterized by being carried out at a temperature of 250 to 300 ℃. When the anode is bonded, the laminate in which the aluminum film 210 or 220 and the glass substrate 100 are stacked is maintained at 250 to 300 ° C., so that when the same electrical force is applied, a large amount of aluminum ions are effectively produced in a short time. 100).

The temperature of 250 to 300 ℃ is much lower than the annealing point of the glass (about 390 ℃ in the case of soft glass), thereby causing no deformation, distortion or damage of the glass and effective strengthening of the glass substrate There is a characteristic that is made.

In addition, unlike chemical strengthening, the external aluminum ions present in the aluminum film are forcibly introduced into the glass substrate by using electric force, rather than the exchange of alkali ions inside the glass with the outside ions. Regardless of the additive, there is an advantage that can be applied to any glass substrate, and even if the main composition of the glass substrate is different, there is an advantage that similar strength can be obtained under similar conditions. Substantially, the glass substrate that can be strengthened by the manufacturing method of the present invention includes silicate-based glass, borate-based glass or phosphate-based glass, and may be considered for use in packaging with optical devices including CCD and CMOS, display devices, and the like. In this case, the glass substrate includes soda lime glass.

As described above, the amount of aluminum ions introduced into the glass substrate 100 by the magnitude of the voltage applied during the anode voltage, the profile of the voltage applied during the anode bonding, and the time when the anode bonding is performed, the glass The ion concentration profile according to the glass substrate thickness of the aluminum ions introduced into the substrate and the depth of the aluminum ions introduced into the glass substrate are controlled.

As shown in FIG. 4, during the anodic bonding, it is preferable that a multi-step boosting step is performed in which a voltage applied is sequentially boosted a plurality of times at regular time intervals from a ground to a maximum value of the voltage.

The high concentration of aluminum ions is locally introduced into the lower region of the surface of the glass substrate 100 where the anodic bonding is performed by contacting the aluminum film 210 or 220 by the multi-step boosting, thereby increasing the magnitude of the stress caused by the aluminum ions. There is an effect to enhance and concentrate the stress in the surface area of the glass substrate 100.

The number of times of the multi-step boosting is preferably 8 to 12 times, and the value of the voltage boosted during the multi-step boosting is preferably a constant value. That is, as shown in FIG. 4, it is preferable that anodic bonding is performed according to a voltage application profile in which a voltage is increased in multiple steps at regular time intervals with a constant voltage as a boosted value up to a maximum value of the voltage. . The time interval t1 at which the multi-stage boosting is performed may be different or the same, and the time interval is preferably 2 minutes to 10 minutes. It is preferable that the time for which the maximum value of the voltage is maintained after the multi-step boosting is also 2 minutes to 10 minutes similar to the time interval t1 at which the multi-step boosting is performed. At this time, in consideration of the thickness of the glass substrate to be strengthened, the number of times of multi-stage boosting, the holding time after reaching the maximum applied voltage, and the time interval t1 between the multi-stage boosting may be appropriately adjusted.

FIG. 5 is a vacuum press of a 6 mm thick aluminum foil on a 0.5 mm thick soda-lime glass substrate, followed by multi-step boosting over 10 steps at 5 minute intervals to boost the same voltage value from 0 to 900 V. After anodic bonding is maintained for a minute, the interface between the anodized aluminum foil and the glass substrate is observed with a high magnification transmission electron microscope. As can be seen in FIG. 5, it can be seen that Al atoms in the upper right side are diffused into the glass (amorphous) in the lower left side, and are indicated by dotted lines and arrows in FIG. 5. It can be seen that the fine surface defects of? Were removed by the anodic bonding with the aluminum film.

6 is a view showing the measurement of the bending strength of the tempered glass prepared according to the present invention, 'glass with Al anodic bonding layer' shown in Figure 6 is a soda-lime glass substrate of 0.5mm thickness using a sputter (sputter) After forming an aluminum film having a thickness of 10 to 20 nm in the film, and then performing a multi-step boosting step 10 over 5 steps at intervals of 5 minutes so that the same voltage value is increased from 0 to 900 V and performing an anodic bonding to maintain at 900V for 5 minutes It means the result of testing the bending strength of tempered glass substrate, 'bare-glass' means the result of testing the bending strength of the glass substrate itself which is not strengthened, and 'glass with sputtered TiW / Cu layers' It means the result of testing the bending strength of a comparative sample in which a multilayer thin film of TiW (300 nm) and Cu (600 nm) was formed by vacuum deposition on a glass substrate.

6, it can be seen that all of the tempered glass substrates manufactured according to the present invention increase the bending strength by 30% to 50% compared to the glass substrates which are not strengthened. In addition, even though the multilayer metal film is deposited on the surface of the glass substrate through the sample of the multilayer metal film deposited on the glass substrate, the increase in strength is very small compared to the glass substrate which is not strengthened. In addition, the bending strength measured when the aluminum film was removed also increased the bending strength from 30% to 50% compared to the glass substrate not strengthened similarly to the case where the transparent aluminum film was present ('glass with Al anodic bonding layer' of FIG. 6). I could see.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention. .

Claims (9)

a1) vacuum pressing the glass substrate and the aluminum film;
b) anodically bonding the glass substrate and the aluminum film with an electrode positioned to face the aluminum film with the glass substrate therebetween as a cathode and the aluminum film as an anode; And
c) dissolving and removing the anodized aluminum film;
Method for producing a tempered glass substrate, characterized in that carried out including. a2) depositing aluminum on a glass substrate to form a transparent aluminum film having a thickness of 10 to 30 nm; And
b) anodically bonding the glass substrate and the aluminum film with an electrode positioned to face the aluminum film with the glass substrate therebetween as a cathode and the aluminum film as an anode;
Method for producing a tempered glass substrate, characterized in that carried out including. 3. The method according to claim 1 or 2,
The method of manufacturing a tempered glass substrate, characterized in that the defect present on the surface of the glass substrate is removed by the anode bonding. 3. The method according to claim 1 or 2,
The method of manufacturing a tempered glass substrate, characterized in that the bending strength of the glass substrate is increased by 30 to 50% by the anode bonding. 3. The method according to claim 1 or 2,
The anode bonding of step b) is a method of manufacturing a tempered glass substrate, characterized in that performed at a temperature of 250 to 300 ℃. 6. The method of claim 5,
The method of manufacturing a tempered glass substrate, characterized in that the maximum value of the voltage applied during the anodic bonding of step b) is 800 to 1000V. The method according to claim 6,
The method of manufacturing a tempered glass substrate, characterized in that during the anodic bonding in step b), a multi-stage boosting step is performed to sequentially boost 8 to 12 times at regular time intervals up to the maximum value of the voltage. delete The method of claim 2,
The method of manufacturing a tempered glass substrate, characterized in that the aluminum film present on the glass substrate after the anodic bonding of step b) is not removed.

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