Plate glass and preparation method thereof

Abstract

The embodiment of the invention provides plate glass and a preparation method thereof, and relates to the field of electronic packaging materials. The plate glass comprises the following main components: SiO2, Al2O3, B2O3 and R2O, the R2O is selected from one, two or three of Li2O, Na2O and K2O, and the plate glass comprises the following components in percentage by mole of oxides: 60-75% of SiO2, 10-20% of Al2O3, 5-10% of B2O3, 5-10% of K2O, 5-10% of Li2O, 5-10% of Na2O and 5-10% of K2O. 0.5%-3.0% of Al2O3 (aluminum oxide); 18% to 32% of B2O3; r2O: 4.0% to 8.0%; according to the embodiment of the invention, the components of the plate glass are designed, so that the obtained plate glass has low dielectric constant, low dielectric loss, low thermal expansion coefficient and high thermal stability, and the preparation method is compatible with a mature manufacturing process of a glass material and is suitable for large-scale mass production.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electronic packaging materials, and in particular to a flat glass and a preparation method thereof. Background Art

[0002] In the field of electronic packaging, silicon substrates are commonly used packaging substrates because of their mature processing technology, good electrical properties, high mechanical strength, stable chemical properties, and relatively good thermal conductivity. However, the high dielectric constant of 11.68 and excessively high dielectric loss limit their use in high-frequency electronic packaging applications. Compared to silicon substrates, flat glass substrates have lower dielectric constants and excellent dielectric properties, making them more suitable for high-frequency electronic packaging than silicon substrates.

[0003] Flat glass is a common material for electronic components, and its manufacturing processes mainly include float, rolling and drawing. Currently, commercial glasses used to make packaging substrates include borosilicate glass (Borofloat33), alkali-free alkaline earth aluminosilicate glass (AF32) and Corning's "EAGLE" glass. However, at a frequency of 24GHz, the dielectric loss of these commercial glasses reaches 0.01 or even higher, which is difficult to meet the high-frequency application requirements for low dielectric loss.

[0004] Patent application CN114656155A discloses a microcrystalline glass material for LTCC with low thermal expansion and low dielectric loss and its preparation method. The microcrystalline glass material is based on borosilicate glass and undergoes crystallization to obtain a microcrystalline structure. Its dielectric constant is between 3.4 and 5, and its dielectric loss is less than 1×10 -3 , the thermal expansion coefficient is 2-4ppm / ℃. The microcrystalline glass material has a ceramic phase heterogeneous structure and must be treated by water quenching or crystallization, but conventional flat glass production process needs to avoid glass crystallization.

[0005] Patent application CN111484245A discloses a 5G terminal cover glass with excellent dielectric properties. The cover glass is based on aluminosilicate glass and is chemically strengthened by ion exchange. At a frequency of 3GHz, its dielectric constant is less than 6.6 and its dielectric loss is less than 0.01. The cover glass contains about 12-15wt% of alkali metal and alkaline earth metal oxides, thereby taking into account both low dielectric loss and high flexural strength.

[0006] Contains only SiO 2 Pure quartz glass has excellent dielectric properties. However, it cannot be used for high-frequency electronic packaging because its thermal expansion coefficient does not match that of the silicon substrate. Furthermore, it cannot be produced using the manufacturing process of flat glass because its melting point is too high.

[0007] Therefore, flat glass with low dielectric constant, low dielectric loss, low thermal expansion coefficient and high thermal stability has become a technical problem that needs to be solved urgently. Summary of the invention

[0008] In view of this, an object of an embodiment of the present invention is to provide a flat glass and a preparation method to solve the technical problem that the existing flat glass cannot have low dielectric constant, low dielectric loss, low thermal expansion coefficient and high thermal stability.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] In a first aspect, a flat glass is provided in an embodiment of the present invention, comprising SiO 2 60%~75%; Al 2 O 3 0.5%~3.0%; B 2 O 3 18%~32%; R 2 O 4.0%~8.0%; among which, R 2 O is selected from Li 2 O、Na 2 O and K 2 One, two or three of O.

[0011] In some embodiments, B 2 O 3 / (Al 2 O 3 +SiO 2 ) ratio is 0.2~0.5, R 2 O / (Al 2 O 3 +B 2 O 3 ) ratio is 0.21 to 0.24. These two parameters are used to adjust the overall effect of the network former and network modifier oxides on the final product.

[0012] In some embodiments, SiO 2 and B 2 O 3 The sum of the molar percentages is 90% to 95%.

[0013] In some embodiments, SiO 2 and B 2 O 3 The sum of the molar percentages is 91% to 93%.

[0014] In some embodiments, R 2 The molar percentage of O is 4.6% to 7.7%.

[0015] Based on the flat glass, an electronic component is also provided in an embodiment of the present invention, and the electronic component is encapsulated by the flat glass. The electronic component can be an antenna component, a semiconductor device, or a passive high-frequency component.

[0016] Based on the flat glass, an electronic device is also provided in an embodiment of the present invention, and the electronic device includes the above-mentioned electronic component.

[0017] In a second aspect, an embodiment of the present invention further provides a method for preparing flat glass, the method comprising batching, melting, forming, quenching and annealing, wherein the annealing comprises preliminary annealing and subsequent multi-stage annealing. The multi-stage annealing of the present invention aims to obtain a glass body with a uniform glass state, a single phase, and no stones or bubbles, so as to facilitate subsequent rolling into a flat plate structure.

[0018] In some embodiments, the multi-stage annealing comprises:

[0019] In the first stage, the temperature was reduced from 594°C to 502°C in 36.8 hours;

[0020] In the second stage, the temperature was reduced from 502°C to 456°C in 9.2 hours;

[0021] In the third stage, the temperature was reduced from 456°C to 410°C in 4.6 hours;

[0022] In the fourth stage, the temperature was reduced from 410°C to 210°C within 10 hours;

[0023] In the fifth stage, the electric furnace is turned off and the furnace temperature is allowed to cool naturally to room temperature. After the above steps, the desired flat glass can be obtained.

[0024] In some embodiments, the method for preparing the flat glass specifically comprises the following steps:

[0025] Step 1, ingredients: weigh the following raw materials according to the molar percentage of oxides and mix them evenly: SiO 2 Precursor A, SiO 2 60%~75%; Al 2 O 3 Precursor B, with Al 2 O 3 0.5%~3.0%; B 2 O 3 Precursor C, based on B 2 O 3 18%~32%; R 2 O precursor D, with R 2 The raw materials are mixed and placed in a corundum crucible, a quartz crucible or a platinum-rhodium crucible.

[0026] There is no particular restriction on the selection of precursors. In some embodiments, precursor A is pure quartz sand with a particle size of 50 to 120 μm; precursor B is selected from alumina (Al 2 O 3 ), aluminum hydroxide (Al(OH) 3 ) or aluminum nitrate nonahydrate (Al(NO 3 ) 3 ·9(H 2 O)) in one or more; Precursor C is boric acid (H 3 BO 3 ); the precursor D is selected from lithium carbonate (Li 2 CO 3 ), sodium sulfate (Na 2 SO 4 ), sodium carbonate (Na 2 CO 3 ), potassium carbonate (K 2 CO 3 ) or potassium nitrate (KNO 3 )

[0027] Step 2, melting: The mixed raw material prepared in step 1 is heated to 1200°C. In some embodiments, the heating time is about 3.83 hours. Then, the temperature is continued to be raised to 1480°C to 1620°C for about 2 to 2.93 hours. Thereafter, the mixture is kept warm and melted in the range of 1480°C to 1620°C for 2 to 2.5 hours to fully melt and homogenize the raw material.

[0028] Step 3, forming and quenching: The glass melt obtained in step 2 is rapidly cooled (quenched) in air and formed in a mold to form a flat glass. In some embodiments, the thickness of the flat glass is 0.5 mm to 2 mm. In some embodiments, the quenching time should be no less than 30 seconds and no more than 10 seconds until the viscosity of the glass melt increases to 10 9.5 The time required for parking.

[0029] Step 4, preliminary annealing: quickly transfer the flat glass obtained in step 3 to an environment with a temperature of 542° C. to 607° C. for heat preservation, and the heat preservation time shall not exceed 0.5 hours.

[0030] Step 5: adopt the multi-stage annealing as described above to obtain the flat glass for electronic component packaging.

[0031] According to the flat glass provided in the embodiment of the present invention, the flat glass has low dielectric constant, low dielectric loss, low thermal expansion coefficient and high thermal stability by designing the composition of the flat glass, so that the flat glass can be used to encapsulate high-frequency electronic components. In addition, the preparation method of the flat glass is compatible with the mature manufacturing process of glass materials and is suitable for large-scale mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a graph showing changes in dielectric constant and dielectric loss of the flat glass prepared in Example 1 of the embodiments of the present invention within a frequency range of 100 Hz to 1 MHz;

[0033] Figure 2 The thermal expansion diagram of the flat glass prepared in Example 1 of the embodiments of the present invention in the temperature range of 20 to 630° C.;

[0034] Figure 3 This is a Raman scattering spectrum of the flat glass prepared in Example 1 of the embodiments of the present invention;

[0035] Figure 4 This is a fitting diagram of the Raman scattering peak of the flat glass prepared in Example 1 of the embodiments of the present invention. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the technical solutions of the present invention, rather than all the embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] To facilitate understanding, some concepts that may be involved in the embodiments of the present invention are first briefly introduced.

[0038] Flat glass: usually refers to a glass body whose geometric dimensions in one spatial dimension are significantly smaller (one order of magnitude) than the other two dimensions, that is, the thickness of the glass body is at least one order of magnitude smaller than its length and width. Depending on the aspect ratio, flat glass can be in the form of sheets or strips. For example, the thickness of flat glass is 0.5mm to 2mm, and the length and width are at least 20mm.

[0039] Coefficient of thermal expansion: Unless otherwise specified, it refers to the linear thermal expansion coefficient (α), and the given value range is applicable to 20°C to 300°C. This coefficient is also often expressed as "CTE", and its value is the average thermal expansion coefficient determined by static measurement according to ISO 7991 standard.

[0040] Dielectric loss: also known as "loss tangent" or "tanδ", is used to describe the energy dissipation characteristics of the flat glass in the embodiments of the present invention. The lower the dielectric loss value, the better the performance of the material. The complex dielectric constant is used to characterize the ability of the glass material to store electrical energy under the action of an external electric field. Dielectric loss can also be expressed as the ratio of the imaginary part to the real part of the complex dielectric constant. Among them, the ratio of the real part to the vacuum dielectric constant is the "dielectric coefficient". These parameters are closely related to the frequency of the external electric field.

[0041] Network former: a concept proposed by Zachariasen.

[0042] Network-modified oxide: a concept also proposed by Zachariasen.

[0043] Existing flat glass has the technical problem of not being able to simultaneously have low dielectric constant, low dielectric loss, low thermal expansion coefficient and high thermal stability.

[0044] In view of the above technical problems, a flat glass is provided in an embodiment of the present invention. The flat glass is composed of a network-forming oxide, and its components, in terms of oxide molar percentage, include silicon dioxide (SiO 2 )60%~75%; Aluminum oxide (Al 2 O 3 )0.5%~3.0%; Boron trioxide (B 2 O 3 ) 18% to 32%; alkali metal oxide (R2O) 4.0% to 8.0%; wherein R2O is selected from Li 2 O、Na 2 O or K 2 O, and B 2 O 3 / (Al 2 O 3 +SiO 2 ) ratio is 0.2~0.5, R 2 O / (Al 2 O 3 +B 2 O 3 ) ratio is 0.21~0.24.

[0045] In the embodiment of the present invention, aluminum oxide is also regarded as a kind of network former. Silicon dioxide and boron trioxide are the main structures of the network former of flat glass, and the sum of their percentage molar contents is 90% to 95%, more specifically 91% to 93%. 2 O 3 / (Al 2 O 3 +SiO 2) ratio and the contents of the three components to adjust the composition of the network former.

[0046] In the embodiment of the present invention, alkali metal oxide (R2O) is used as a network modifier oxide. By adding alkali metal oxide components to the components of the glass material and adding them according to an appropriate ratio, the melting properties of the glass material can be improved. By limiting the release of alkali metal oxides on the glass surface and the fluidity of alkali metal oxides in the glass matrix, effective control of the migration of alkali metal ions in the glass material can be achieved, which is not only beneficial to improving the thermal stability of the flat glass, but also beneficial to achieving low dielectric loss.

[0047] In the embodiment of the present invention, by controlling R 2 O / (Al 2 O 3 +B 2 O 3 ) ratio to achieve the function / risk control optimization of alkali metal oxides. In a possible implementation, the content of alkali metal oxides is controlled in the range of 4% to 8% by mole, more preferably 4.6% to 7.7%.

[0048] In the embodiment of the present invention, the electronic component can be obtained by using flat glass packaging. The electronic component can specifically be an antenna component, a semiconductor device, or a passive high-frequency component. The electronic component is used to manufacture electronic equipment.

[0049] The present invention also provides a method for preparing a flat glass, comprising the following steps:

[0050] Batching: weigh and mix the materials according to the proportion;

[0051] Melting: The material is heated through a certain procedure to achieve melting and homogenization;

[0052] Molding and quenching: pouring the molten glass into a mold and initially cooling it;

[0053] Annealing: includes preliminary annealing to eliminate the internal stress of the glass, and continued annealing to obtain the final product.

[0054] In the embodiment of the present invention, the heat treatment process significantly affects the homogeneity of the flat glass, especially the optical homogeneity, which can be clearly reflected by the refractive index related test. Therefore, we provide a better preparation method while providing a high-quality formula, that is, multi-stage annealing is used during the continuous annealing to ensure the homogeneity and the thermal stability of the glass during high-temperature processing. The multi-stage annealing includes:

[0055] In the first stage, the temperature was reduced from 594°C to 502°C in 36.8 hours;

[0056] In the second stage, the temperature was reduced from 502°C to 456°C in 9.2 hours;

[0057] In the third stage, the temperature was reduced from 456°C to 410°C in 4.6 hours;

[0058] In the fourth stage, the temperature was reduced from 410°C to 210°C within 10 hours;

[0059] In the fifth stage, the electric furnace is turned off and the furnace temperature is allowed to cool naturally to room temperature. After the above steps, the desired flat glass can be obtained.

[0060] The technical solution of the present invention is described below through specific embodiments, and the contents of these specific embodiments do not constitute a limitation on the protection scope of the present invention.

[0061] Example 1

[0062] A flat glass is prepared by the following method:

[0063] Ingredients: weigh the raw materials according to the formula, sodium carbonate (Na 2 CO 3 ) 135.71 g, boric acid (H 3 BO 3 ) 633.37 g, quartz sand (SiO2) 1230.92 g, alumina (Al 2 O 3 ) 82.25 g. Use a mixer to mix all the raw materials thoroughly to obtain a uniform mixture.

[0064] Melting: Place the mixture in a corundum crucible and place it in an electric furnace for melting. According to the set heating program, the furnace temperature is raised to 1200°C within 3.83 hours, then further raised to 1620°C within 2.8 hours, and kept at 1620°C for 2 hours to fully melt and homogenize the glass raw materials.

[0065] Molding and quenching: The molten glass is quickly poured into the mold and quenched in the air. A flat glass with a thickness of 1.35 mm is formed through a rolling process and the cooling is continued for about 45 seconds.

[0066] Preliminary annealing: The prepared flat glass is quickly transferred to a muffle furnace set at 594°C and kept warm for 15 minutes to eliminate the internal stress of the glass.

[0067] Multi-stage annealing: The flat glass body is subjected to multi-stage cooling annealing treatment:

[0068] In the first stage, the temperature was reduced from 594°C to 502°C in 36.8 hours;

[0069] In the second stage, the temperature was reduced from 502°C to 456°C in 9.2 hours;

[0070] In the third stage, the temperature was reduced from 456°C to 410°C in 4.6 hours;

[0071] In the fourth stage, the temperature was reduced from 410°C to 210°C within 10 hours;

[0072] In the fifth stage, the electric furnace is turned off and the furnace temperature is allowed to cool naturally to room temperature. After the above steps, the desired flat glass can be obtained.

[0073] In order to test the dielectric properties, a 10 mm × 10 mm square sample was cut from the prepared flat glass and a silver electrode was plated on its surface. The dielectric constant and dielectric loss of the sample were tested in the frequency range of 100 Hz to 1 MHz using the balanced bridge method.

[0074] Figure 1 This is a graph showing changes in dielectric constant and dielectric loss of the flat glass prepared in Example 1 of the embodiments of the present invention within a frequency range of 100 Hz to 1 MHz.

[0075] Reference Figure 1 As shown in the figure, the test results show that the dielectric constant and dielectric loss decrease with increasing frequency. At 1MHz, the dielectric constant is 4.61 and the dielectric loss (tanδ) is 0.0025.

[0076] When testing the dielectric properties of the sample in the frequency band of 1 MHz to 1 GHz, a square sample of 20 mm×20 mm can be cut from the prepared flat glass and tested using the parallel plate capacitance method.

[0077] In order to characterize the thermal properties of flat glass, the glass transition temperature (Tg) and softening point of the glass were measured by combining a thermal dilatometer (DIL) and a differential thermal analyzer (DSC).

[0078] Figure 2 This is a thermal expansion diagram of the flat glass prepared in Example 1 of the present invention in the temperature range of 20 to 630°C. The figure includes the curves of the linear expansion rate (dL / L0) and the thermal expansion coefficient (CTE) of the flat glass changing with temperature. Figure 2 As shown, in the temperature range of 20 to 300°C, the average thermal expansion coefficient of flat glass is 3.85 ppm / K.

[0079] Figure 3 This is a Raman scattering spectrum of the flat glass prepared in Example 1 of the present invention. By analyzing the Raman spectrum, the structural unit information of the glass material can be obtained. Figure 3As shown, the flat glass prepared in Example 1 mainly comprises three types of silicon-oxygen structural units, aluminum-oxygen structural units and two types of boron-oxygen structural units.

[0080] Figure 4 This is a fitting diagram of the Raman scattering peak of the flat glass prepared in Example 1 of the embodiments of the present invention. Figure 4 for Figure 3 Schematic diagram of peak fitting analysis of Raman spectrum. Figure 3 As shown in the figure, the alkali distribution, silicon-oxygen coordination distribution, boron coordination distribution and aluminum-oxygen coordination distribution can be further determined, and the migration degree of alkali metal ions in the glass material under the action of an external electric field can be further evaluated. The migration behavior of alkali metal ions is closely related to their distribution mode. If the migration of alkali metal ions is restricted, the dielectric loss of the glass is expected to be reduced.

[0081] Example 2

[0082] The preparation method of the flat glass of Example 2 is basically the same as that of Example 1, and the main difference lies in the raw material formula. In Example 2, the weighing amount of each raw material is: potassium carbonate (K 2 CO 3 ) 35.39 g, sodium carbonate (Na 2 CO 3 ) 108.57 g, boric acid (H 3 BO 3 ) 633.37 g, quartz sand 1230.92 g, alumina (Al 2 O 3 ) 82.25 g. The obtained flat glass was measured for relevant parameters according to the method of Example 1.

[0083] The advantage of this formulation is that it can better control the migration of alkali metal ions in the glass, thereby reducing dielectric loss. However, the cost of this optimization is a slight increase in the dielectric constant of the glass.

[0084] Example 3

[0085] The raw material formula of the flat glass of Example 3 is: sodium carbonate (Na 2 CO 3 ) 196.04 g, boric acid (H 3 BO 3 ) 914.91 g, quartz sand 889.05 g, alumina (Al 2 O 3 )24.52 grams.

[0086] The preparation method is as follows:

[0087] Ingredients: Weigh the raw materials according to the formula, use a mixer to fully mix all the raw materials to obtain a uniform mixture.

[0088] Melting: Place the mixture in a corundum crucible and put it into an electric furnace for heating and melting according to the set heating program: heat to 1200°C within 3.83 hours, then heat to 1540°C within 2.3 hours, and keep at 1540°C for 2 hours to ensure the homogenization of the glass liquid.

[0089] Molding and quenching: The molten glass is quickly poured into the mold and quenched in the air. A flat glass with a thickness of 1.35 mm is formed through a rolling process and the cooling is continued for about 45 seconds.

[0090] Preliminary annealing: The obtained flat glass body was quickly placed in a muffle furnace set at 581°C and kept at this temperature for 15 minutes for preliminary annealing.

[0091] Multi-stage annealing: cool down to 487°C within 37.6 hours; then cool down to 440°C within 9.4 hours; then cool down to 393°C within 4.7 hours; and then cool down to 210°C within 9.2 hours; after that, cool naturally to room temperature in the electric furnace to obtain the final flat glass product.

[0092] The relevant parameters of the prepared flat glass were measured according to the method of Example 1.

[0093] The advantages of the formula and preparation method of Example 3 are: the melting temperature is relatively low, and under this condition, the migration of alkali metal ions is effectively suppressed, so that only a small sacrifice is made in terms of dielectric loss performance. In addition, the liquidus viscosity of the glass of this formula is lower, which is conducive to the uniformity of the rolling process. At the same time, the higher sodium content of alkali metal ions also creates favorable conditions for subsequent processes such as chemical strengthening by ion exchange.

[0094] Comparative Example 1

[0095] The preparation method of the flat glass of Comparative Example 1 is basically the same as that of Example 1, and the main difference lies in the raw material formula. In Comparative Example 1, the weighing amount of each raw material is: strontium carbonate (SrCO 3 ) 289.15 g, boric acid (H 3 BO 3 ) 914.91 g, quartz sand 889.05 g, alumina (Al 2 O 3 )24.52 grams, and the relevant parameters of the prepared flat glass were measured according to the method of Example 1.

[0096] Comparative Example 2

[0097] The flat glass preparation process of Comparative Example 2, its ingredients, melting-quenching and rolling steps are the same as those of Example 3, and the main difference is the heat treatment process. In Comparative Example 2, the flat glass body is placed in a constant temperature environment of 550° C. for 48 hours, and then cooled to room temperature by natural cooling.

[0098] Compared with Example 3, the flat glass prepared in Comparative Example 2 is more likely to produce microcracks during subsequent cutting or polishing processes. In addition, the refractive index test found that the homogeneity of the flat glass was significantly poor, which would have an adverse effect on the thermal stability of the glass during high-temperature processing.

[0099] Table 1: Electrical properties of the flat glass obtained in Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2

[0100]

[0101] The glass materials of Examples 1, 2, and 3 and Comparative Examples 1 and 2 in the embodiments of the present invention are all alkali borosilicate glass systems. The difference is that Examples 1, 2, and 3 finely control the content and distribution of alkali metals and adjust the heat treatment process accordingly. Comparative Examples 1 and 2 lack alkali metals, and only use the traditional long-term constant temperature insulation followed by natural cooling treatment process in the heat treatment process.

[0102] The properties of the flat glass obtained in Example 1, Example 2, Example 3 and Comparative Example 1 and Comparative Example 2 are shown in Table 1. The data in the table show that the flat glass prepared by the method for preparing flat glass in the embodiment of the present invention can achieve excellent properties of dielectric loss as low as 0.003 at room temperature and 1 MHz frequency, thermal expansion coefficient as low as 3.85 ppm / K, dielectric constant in the range of 4.6 to 8.9, and good glass homogeneity.

[0103] In contrast, due to the lack of alkali metals and the use of only the traditional long-term constant temperature insulation followed by natural cooling treatment in the heat treatment process, the homogeneity of the flat glass prepared in Comparative Examples 1 and 2 is one order of magnitude lower than that in Example 1, Example 2, and Example 3, and technical problems such as microcracks and broken edges are prone to occur during the thermal mechanical processing.

[0104] It can be seen that the present invention designs the composition of the glass material so that the flat glass has low dielectric constant, low dielectric loss, low thermal expansion coefficient and high thermal stability, so that it can be used to encapsulate high-frequency electronic components. The preparation method of the flat glass is compatible with mature traditional manufacturing processes and is suitable for large-scale mass production.

Claims

1. Flat glass, characterized in that: Calculated by molar percentage of oxides, it includes SiO2 60%-75%, Al2O3 0.5%-3.0%, B2O3 18%-32%, and R2O 4.0%-8.0%, wherein R2O is selected from one, two or three of Li2O, Na2O and K2O.

2. The flat glass according to claim 1, characterized in that: The ratio of B2O3 / (Al2O3+SiO2) is 0.2~0.5, and the ratio of R2O / (Al2O3+B2O3) is 0.21~0.

24.

3. The flat glass according to claim 1, characterized in that: The sum of the molar percentages of SiO2 and B2O3 is 90% to 95%.

4. The flat glass according to claim 1, characterized in that: The sum of the molar percentages of SiO2 and B2O3 is 91% to 93%.

5. The flat glass according to claim 1, characterized in that: The molar percentage of R2O is 4.6% to 7.7%.

6. An electronic component, characterized in that The electronic components are encapsulated by the flat glass described in any one of claims 1-4.

7. An electronic device, characterized in that The electronic device comprises the electronic component according to claim 6.

8. A method for preparing flat glass, the method comprising batching, melting, forming and quenching, and annealing, wherein the annealing comprises preliminary annealing and subsequent multi-stage annealing, characterized in that: The multi-stage annealing comprises: In the first stage, the temperature was reduced from 594°C to 502°C in 36.8 hours; In the second stage, the temperature was reduced from 502°C to 456°C in 9.2 hours; In the third stage, the temperature was reduced from 456°C to 410°C in 4.6 hours; In the fourth stage, the temperature was reduced from 410°C to 210°C within 10 hours; In the fifth stage, the electric furnace is turned off and the furnace temperature is allowed to cool naturally to room temperature.

9. The method for preparing flat glass according to claim 8, characterized in that: The batching, melting, forming and quenching, and preliminary annealing steps of the method respectively include: Ingredients: According to the molar percentage of oxides, weigh the following raw materials and mix them evenly: SiO2 precursor A, calculated as SiO2, 60% to 75%; Al2O3 precursor B, calculated as Al2O3, 0.5% to 3.0%; B2O3 precursor C, calculated as B2O3, 18% to 32%; R2O precursor D, calculated as R2O, 4.0% to 8.0%; Melting: Heat the mixed raw materials to 1200°C, then continue to raise the temperature to 1480°C ~ 1620°C, and keep melting at 1480°C ~ 1620°C for 2 to 2.5 hours to fully melt and homogenize the raw materials; Molding and quenching: The molten glass is rapidly cooled in the air and then molded in a mold; Preliminary annealing: The formed flat glass is quickly transferred to an environment with a temperature of 542℃~607℃ for insulation, and the insulation time shall not exceed 0.5 hours.

10. The method for preparing flat glass according to claim 9, characterized in that: The time for heating to 1200°C in the melting step is 3.83 hours, and the time for heating to 1480°C to 1620°C is about 2 to 2.93 hours. In the forming and quenching steps, the forming thickness of the flat glass is 0.5mm to 2mm, and the time for rapid cooling in the air should be no less than 30 seconds and no more than the time when the viscosity of the glass melt increases to 10 9.5 The time required for parking.

Images