CN109987836A - E-glass - Google Patents

Abstract

The present invention relates to alkali-free glass. The present invention relates to an alkali-free glass with a low shrinkage rate, a small average thermal expansion coefficient at 50°C to 350°C, and easy float forming. Specifically, the present invention relates to an alkali-free glass having a shrinkage rate C1 of 5 ppm or less, a shrinkage rate C2 of 40 ppm or less, and the alkali-free glass containing SiO ₂ in mass % based on oxides 64-72, Al ₂ O ₃ 17-22, MgO 1-8, CaO 4-15.5, and 0.20≤MgO/(MgO+CaO)≤0.41.

Description

E-glass

This application is a divisional application of a Chinese patent application with an application date of June 24, 2014 and an application number of 201480036107.X.

technical field

The present invention relates to a substrate glass for a display or a substrate glass for a photomask that is suitable for use in the production of various flat panel displays (FPD), does not substantially contain an alkali metal oxide, has a low shrinkage rate, and is capable of float forming. Alkali-free glass.

Background technique

Conventionally, the following properties as shown in Patent Document 1, for example, have been required for various substrate glasses for displays, in particular, substrate glasses for displays in which a metal or oxide thin film or the like is formed on the surface thereof.

(1) When an alkali metal oxide is contained, the alkali metal ions diffuse into the thin film to degrade the film properties, and therefore, it is required to substantially not contain alkali metal ions.

(2) Sufficient chemical durability against various chemicals used in semiconductor formation. In particular, buffered hydrofluoric acid (BHF: a mixed solution of hydrofluoric acid and ammonium fluoride) used for etching _SiOx or _SiNx , a chemical solution containing hydrochloric acid used for etching ITO, and etching of metal electrodes Various acids (nitric acid, sulfuric acid, etc.) and alkalis of resist stripping solutions are durable.

(3) There are no defects (bubbles, streaks, inclusions, pits, scratches, etc.) inside and on the surface.

In addition to the above requirements, the following situations have occurred in recent years.

(4) The weight reduction of a display is requested|required, and it is desired that the glass itself is also a glass with a low density.

(5) The weight reduction of a display is requested|required, and thin plate glass of a board|substrate is desired.

(6) In addition to the conventional amorphous silicon (a-Si) type liquid crystal display, a polycrystalline silicon (p-Si) type liquid crystal display with a slightly higher heat treatment temperature (a-Si: about 350°C→p-Si: 350～550℃).

(7) Glass having a small average thermal expansion coefficient is required to increase productivity or improve thermal shock resistance by increasing the rate of temperature rise and fall in the heat treatment in the production of liquid crystal displays.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2001-348247

SUMMARY OF THE INVENTION

The problem to be solved by the invention

In addition to the properties described in the background art, in recent years, in order to minimize the deformation of the glass and the dimensional change accompanying the stabilization of the structure of the glass when exposed to high temperature in the film forming process, the shrinkage rate of the glass is required to be low.

An object of the present invention is to provide an alkali-free glass that has a low shrinkage rate, a small average thermal expansion coefficient, and is easy to float molding.

means to solve the problem

The present invention provides an alkali-free glass, wherein the alkali-free glass has a shrinkage rate C1 of 5 ppm or less, a shrinkage rate C2 of 40 ppm or less, and the alkali-free glass contains:

0.20≤MgO/(MgO+CaO)≤0.41.

In the alkali-free glass of the present invention, it is preferable that the shrinkage rate C1 of the alkali-free glass is 5 ppm or less, the shrinkage rate C2 is 25 ppm or less, and the alkali-free glass contains:

The total amount of SiO ₂ , Al ₂ O ₃ , MgO and CaO is 96% by mass or more, and

0.22≤MgO/(MgO+CaO)≤0.39.

In addition, in the alkali-free glass of the present invention, the alkali-free glass preferably has a shrinkage rate C1 of 5 ppm or less, a shrinkage rate C2 of 40 ppm or less, and the alkali-free glass contains:

The total amount of SiO ₂ , Al ₂ O ₃ , MgO and CaO is 96% by mass or more, and

0.22≤MgO/(MgO+CaO)≤0.39.

Invention effect

The alkali-free glass of the present invention is suitable as a substrate glass for various displays or a substrate glass for a photomask, and can also be used as a glass substrate for magnetic disks and the like. However, due to the low shrinkage rate, various display substrate glasses and photomask substrates are required to minimize the deformation of the glass and the dimensional change accompanying the stabilization of the glass structure when exposed to high temperature in the film forming process. Glass is effective.

specific implementation form

Next, the composition range of each component is demonstrated. When SiO ₂ exceeds 72% (mass %, unless otherwise specified, the same applies hereinafter), the devitrification temperature _TL may increase. In addition, the viscosity is also high, the melting temperature is increased, and the air bubbles may not be completely removed during clarification, and the air bubbles may be mixed. When it is less than 64%, the ratio of the network former decreases, and the shrinkage ratio increases. Furthermore, the average thermal expansion coefficient becomes large.

Here, in the first aspect of the alkali-free glass of the present invention, the SiO ₂ content is 67.5% or more and 72% or less. When the content exceeds 72%, the viscosity becomes high, the melting temperature rises, and the bubbles may not be completely removed during clarification and may be mixed in. When it is less than 67.5%, the shrinkage rate may increase. More preferably, it is 68% or more.

In the second aspect of the alkali-free glass of the present invention, the SiO ₂ content is 64% or more and 68% or less. When it exceeds 68%, the melting temperature may increase. More preferably, it is 67% or less. When it is less than 64%, the shrinkage rate may increase. Furthermore, the average thermal expansion coefficient becomes large.

When Al ₂ O ₃ exceeds 22%, the devitrification temperature _TL may increase. Furthermore, since it is a network former like SiO ₂ , when it exceeds 22%, the viscosity increases, the melting temperature increases, and there is a possibility that air bubbles are mixed. When it is less than 17%, an increase in shrinkage is caused.

Here, in the first aspect of the alkali-free glass of the present invention, the Al ₂ O ₃ content is 17% or more and 21% or less. When it exceeds 21%, the devitrification temperature _TL may increase. More preferably, it is 20.5% or less. When it is less than 17%, an increase in shrinkage is caused, and it is more preferably 18% or more.

In the second aspect of the alkali-free glass of the present invention, the Al ₂ O ₃ content is 17% or more and 22% or less. When it exceeds 22%, the devitrification temperature _TL may increase. More preferably, it is 21% or less. When it is less than 17%, an increase in shrinkage is caused, and it is more preferably 18% or more.

When MgO exceeds 8%, the glass transition temperature Tg decreases, the shrinkage rate increases, and the average thermal expansion coefficient increases. When it is less than 1%, the solubility deteriorates, the Young's modulus decreases, and the devitrification temperature _TL increases.

Here, in the first aspect of the alkali-free glass of the present invention, the MgO content is 1% or more and 6% or less. When it exceeds 6%, the glass transition temperature Tg decreases, the shrinkage rate increases, and the average thermal expansion coefficient increases. More preferably, it is 5% or less. When it is less than 1%, the devitrification temperature _TL increases and the Young's modulus decreases. More preferably, it is 2% or more.

In the second aspect of the alkali-free glass of the present invention, the MgO content is 2.3% or more and 8% or less. When it exceeds 8%, the shrinkage rate increases and the average thermal expansion coefficient becomes large. When it is less than 2.3%, the devitrification temperature _TL increases. Also, the Young's modulus decreases. More preferably, it is 4% or more.

When CaO exceeds 15.5%, an increase in shrinkage or an increase in devitrification temperature _TL is caused. When it is less than 4%, the solubility is deteriorated, the melting temperature is increased, and the devitrification temperature is also increased.

Here, in the first aspect of the alkali-free glass of the present invention, the CaO content is 4% or more and 8.5% or less. When it exceeds 8.5%, an increase in shrinkage rate or an increase in devitrification temperature _TL is caused. When it is less than 4%, the solubility is deteriorated, the melting temperature is increased, and the devitrification temperature is also increased. More preferably, it is 5% or more.

In the second aspect of the alkali-free glass of the present invention, the CaO content is 9% or more and 15.5% or less. When it exceeds 15.5%, an increase in shrinkage rate or an increase in devitrification temperature _TL is caused. When it is less than 9%, the solubility deteriorates and the melting temperature increases. More preferably, it is 10% or more.

When MgO/(CaO+MgO) is more than 0.41, the shrinkage rate at the time of heat processing at 600 degreeC increases. Furthermore, the average thermal expansion coefficient becomes large. It is preferably 0.39 or less, and more preferably 0.37 or less. When it is less than 0.20, the devitrification temperature _TL increases. It is preferably 0.22 or more, and more preferably 0.24 or more.

Other components, such as the following components, may be contained within a range that does not inhibit the effects of the present invention. The other components in this case are preferably less than 5%, more preferably less than 4%, more preferably less than 3%, still more preferably less than 1%, still more preferably less than 0.5%, in order to achieve both high Young's modulus and low shrinkage ratio. It is particularly preferable not to contain substantially, that is, not to contain unavoidable impurities. Therefore, in the present invention, the total content of SiO ₂ , Al ₂ O ₃ , CaO and MgO is preferably 95% or more, more preferably 96% or more, more preferably 97% or more, still more preferably 99% or more, and still more Preferably it is 99.5% or more. It is particularly preferable to consist essentially of SiO ₂ , Al ₂ O ₃ , CaO and MgO, that is, to consist of SiO ₂ , Al ₂ O ₃ , CaO and MgO except for unavoidable impurities.

In order to improve the melting reactivity of glass, B ₂ O ₃ may be contained. However, when there is too much B ₂ O ₃ , the Young's modulus decreases and the shrinkage rate increases, so the content is preferably less than 3%, more preferably less than 1%, and particularly preferably not substantially contained.

In order to improve the solubility of glass, BaO may be contained. However, when there is too much BaO, the average thermal expansion coefficient increases, so the content is preferably less than 5%, more preferably less than 3%, still more preferably less than 1%, still more preferably less than 0.5%, and particularly preferably not substantially contained.

In order to improve solubility, SrO may be contained. However, when there is too much SrO, the average thermal expansion coefficient increases, so the content is preferably less than 5%.

Here, in the first aspect of the alkali-free glass of the present invention, the content of SrO is preferably less than 3%, more preferably less than 1%, still more preferably less than 0.5%, and particularly preferably not substantially contained.

In the second aspect of the alkali-free glass of the present invention, the content of SrO is preferably less than 2%, more preferably less than 1%, more preferably less than 0.3%, and particularly preferably not substantially contained.

In order to increase the Young's modulus of the glass, ZrO ₂ may be contained. However, when there is too much ZrO ₂ , the devitrification temperature increases, so the content is preferably less than 3%, more preferably less than 1%, and particularly preferably not substantially contained.

In addition, in the present invention, in order to improve the solubility, clarity, and formability of the glass, the glass raw material may contain less than 1%, preferably less than 0.5%, more preferably less than 0.3%, and even more preferably less than 0.1% in the total amount. ZnO, SO ₃ , Fe ₂ O ₃ , F, Cl, SnO ₂ .

Note that the glass of the present invention does not contain (ie, does not substantially contain) alkali metal oxides exceeding the impurity level so as not to deteriorate the properties of the metal or oxide thin film provided on the glass surface during panel production. In addition, in order to facilitate recovery of glass, it is preferable that PbO, As ₂ O ₃ and Sb ₂ O ₃ are not substantially contained.

The shrinkage rate of the alkali-free glass of the present invention is extremely low.

The shrinkage rate refers to the thermal shrinkage rate of glass due to relaxation of the glass structure during heat treatment. In the present invention, the shrinkage ratio refers to a value measured by the method described below.

First, the target glass is melted at 1550° C. to 1650° C., the molten glass is then flowed out, molded into a plate shape, cooled, and the obtained plate glass is polished to obtain a glass plate of 100 mm×20 mm×1 mm.

Next, the obtained glass plate was heated to the glass transition temperature Tg+70°C, kept at this temperature for 1 minute, and then cooled to room temperature at a temperature drop rate of 40°C/min. Then, two indentations were made on the surface of the glass plate at intervals A (A=90 mm) in the longitudinal direction to obtain a sample before treatment.

Next, the sample before treatment was heated to 450°C at a temperature increase rate of 100°C/hour, held at 450°C for 2 hours, and then cooled to room temperature at a temperature drop rate of 100°C/hour to obtain a sample 1 after treatment.

Then, the indentation pitch B1 of the sample 1 after the treatment was measured.

The shrinkage rate C1 was calculated from A and B1 thus obtained using the following formula.

C1[ppm]=(A-B1)/A×10 ⁶

In addition, the sample before treatment was heated to 600°C at a temperature increase rate of 100°C/hour, held at 600°C for 1 hour, and then cooled to room temperature at a temperature drop rate of 100°C/hour to obtain sample 2 after treatment.

Then, the indentation pitch B2 of the sample 2 after the treatment was measured.

The shrinkage rate C2 was calculated from A and B2 thus obtained using the following formula.

C2[ppm]=(A-B2)/A×10 ⁶

The shrinkage rate C1 of the alkali-free glass of the present invention is 5 ppm or less, while the shrinkage rate C2 is 40 ppm or less.

The shrinkage ratios C1 and C2 of the alkali-free glass of the present invention satisfy the above-mentioned conditions. Therefore, in the thin-film formation process performed in the process of manufacturing various displays using the alkali-free glass, when exposed to high temperature, the deformation of the glass and the The dimensional change accompanying structural stabilization of glass is suppressed to a minimum.

Here, in the first aspect of the alkali-free glass of the present invention, the shrinkage rate C1 is 5 ppm or less, while the shrinkage rate C2 is 25 ppm or less, and more preferably 20 ppm or less.

In the second aspect of the alkali-free glass of the present invention, the shrinkage rate C1 is 5 ppm or less, while the shrinkage rate C2 is 40 ppm or less, and more preferably 35 ppm or less.

The alkali _- free glass of the present invention preferably has a temperature T2 of 1760°C or lower at which the viscosity η reaches 10 ² poise (dPa·s) in order to facilitate melting and to suppress corrosion of the refractory bricks constituting the melting furnace.

Here, in the first aspect of the alkali-free glass of the present invention, T ₂ is preferably 1760°C or lower, more preferably 1740°C or lower, and still more preferably 1720°C or lower.

In the _2nd aspect of the alkali-free glass of this invention, T2 becomes like this. Preferably it is 1730 degrees C or less, More preferably, it is 1710 degrees C or less, More preferably, it is 1690 degrees C or less.

In addition, for the alkali-free glass of the present invention, in order to facilitate float forming, the temperature T ₄ at which the viscosity η reaches 10 ⁴ poise (dPa·s) is preferably 1380° C. or lower.

Here, in the 1st aspect of the alkali-free glass of this invention, T4 becomes like this _. Preferably it is 1380 degrees C or less, More preferably, it is 1360 degrees C or less, More preferably, it is 1340 degrees C or less.

In the second aspect of the alkali-free glass of the present invention, T ₄ is preferably 1360°C or lower, more preferably 1340°C or lower, and still more preferably 1320°C or lower.

Moreover, in order to improve the thermal shock resistance of the alkali-free glass of this invention, and to improve productivity at the time of manufacturing a panel, it is preferable that the average thermal expansion coefficient in 50-350 degreeC is 40* ^10-7 /degreeC or less.

Here, in the first aspect of the alkali-free glass of the present invention, the average thermal expansion coefficient at 50 to 350°C is preferably 37×10 ^-7 /°C or less, and more preferably 34×10 ^-7 /°C or less.

In the second aspect of the alkali-free glass of the present invention, the average thermal expansion coefficient at 50 to 350°C is preferably 40×10 ^-7 /°C or less, and more preferably 38×10 ^-7 /°C or less.

In the alkali-free glass of the present invention, the glass transition temperature is preferably 780° C. or higher in order to suppress thermal shrinkage during panel production and to be able to apply a method by laser annealing as a p-Si TFT production method.

When the glass transition temperature is 780°C or higher, it is suitable for applications in which the fictive temperature of the glass is likely to rise during the production process (for example, those with a thickness of 0.7 mm or less, preferably 0.5 mm or less, more preferably 0.3 mm or less are used for organic EL and the like). A display substrate or a lighting substrate, or a display substrate or a lighting substrate having a thickness of 0.3 mm or less, preferably a thin plate of 0.1 mm or less).

In the forming of sheet glass with a plate thickness of 0.7 mm or less, further 0.5 mm or less, further 0.3 mm or less, and further 0.1 mm or less, the pull-out speed during forming tends to increase, so the fictive temperature of the glass tends to rise, The shrinkage rate of glass tends to increase. In this case, if it is glass with a high glass transition temperature, the shrinkage rate can be suppressed.

The alkali-free glass of the present invention can be produced, for example, by the following method. The raw material of each component generally used is prepared as the target component, and this is continuously put into a furnace, and it is heated and melted at 1550°C to 1650°C. Sheet glass can be obtained by forming this molten glass into a predetermined thickness by a float method, annealing, and then cutting.

Example

Hereinafter, Examples 1 to 12 are examples, and Examples 13 to 15 are comparative examples. The raw materials of each component were prepared to the target composition, and were melted at a temperature of 1550°C to 1650°C using a platinum crucible. During melting, the glass was homogenized by stirring with a platinum stirrer. Next, molten glass is made to flow out, and it is shape|molded into a plate shape, and annealing is performed.

Tables 1 to 2 show glass compositions (unit: mass %), density ρ (g/cm ³ ), Young's modulus E (GPa) (measured by an ultrasonic method), and specific elastic modulus E/ρ (GP cm ³ /g), glass transition temperature Tg (unit: °C), average thermal expansion coefficient α (unit: ×10 ^-7 /°C) at 50 to 350 °C, temperature T at which glass viscosity η reaches 10 ² poise ₂ (unit: °C), temperature T4 ₍ unit: °C) at which the glass viscosity η reaches 10 ⁴ poise, and shrinkage ratios C1 and C2 (measured according to the above method, unit: ppm).

In addition, in Tables 1 and 2, the values shown in parentheses are calculated values.

As can be seen from the table, the shrinkage rate C1 of the glass of the examples is 5 ppm or less, and the shrinkage rate C2 is 40 ppm or less. In addition, the average thermal expansion coefficient at 50 to 350°C is 40×10 ^-7 /°C or less.

The present invention has been described in detail with reference to the specific embodiments, but it is obvious for those skilled in the art that various changes or modifications can be made without departing from the spirit and scope of the present invention.

This application is based on Japanese Patent Application No. 2013-134900 filed on June 27, 2013, the contents of which are incorporated herein by reference.

Industrial Applicability

The alkali-free glass of the present invention is suitable as a substrate glass for various displays or a substrate glass for a photomask, and can also be used as a glass substrate for magnetic disks and the like. However, due to the low shrinkage rate, various display substrate glasses and photomask substrates are required to minimize the deformation of the glass and the dimensional change accompanying the stabilization of the glass structure when exposed to high temperature in the film forming process. Glass is effective.

Claims (3)

1. An alkali-free glass, wherein the alkali-free glass has a shrinkage rate C1 of 5 ppm or less and a shrinkage rate C2 of 40 ppm or less, In mass % on an oxide basis, the alkali-free glass contains: 0.20≤MgO/(MgO+CaO)≤0.41, and The total amount of SiO ₂ , Al ₂ O ₃ , MgO and CaO is 97% by mass or more, The shrinkage ratio refers to the value measured by the following method: First, the target glass is melted at 1550°C to 1650°C, the molten glass is then flowed out, formed into a plate shape, cooled, and the obtained plate glass is polished to obtain a glass plate of 100 mm × 20 mm × 1 mm, Next, the obtained glass plate was heated to the glass transition temperature Tg+70°C, kept at this temperature for 1 minute, and then cooled to room temperature at a temperature drop rate of 40°C/min, and then, on the surface of the glass plate, along the length of Two indentations were made with an interval A in the edge direction, so as to obtain the sample before treatment, the interval A=90mm, Next, the sample before treatment was heated to 450°C at a temperature increase rate of 100°C/hour, held at 450°C for 2 hours, and then cooled to room temperature at a temperature drop rate of 100°C/hour to obtain a sample after treatment 1, Then, the indentation distance B1 of the sample 1 after the treatment was measured, The shrinkage C1 is calculated from A, B1 thus obtained using the following formula: C1=(A-B1)/A×10 ⁶ , C1 is on the order of ppm; In addition, the sample before treatment was heated to 600°C at a heating rate of 100°C/hour, held at 600°C for 1 hour, and then cooled to room temperature at a temperature drop rate of 100°C/hour to obtain a sample 2 after treatment, Then, the indentation distance B2 of the sample 2 after the treatment was measured, The shrinkage C2 is calculated from A, B2 thus obtained using the following formula: C2=(A-B2)/A×10 ⁶ , C2 is on the order of ppm. 2 . The alkali-free glass according to claim 1 , wherein the shrinkage rate C1 of the alkali-free glass is 5 ppm or less, and the shrinkage rate C2 is 25 ppm or less, 2 . In mass % on an oxide basis, the alkali-free glass contains: and 0.22≤MgO/(MgO+CaO)≤0.39. 3. The alkali-free glass according to claim 1, wherein the alkali-free glass has a shrinkage rate C1 of 5 ppm or less, and a shrinkage rate C2 of 40 ppm or less, In mass % on an oxide basis, the alkali-free glass contains: and 0.22≤MgO/(MgO+CaO)≤0.39.