A packaging glass and a method of manufacturing and use thereof

Abstract

This application relates to an encapsulation glass, its preparation method, and its application. The raw material components of the encapsulation glass, based on the molar percentage of oxides, include: SiO2: 40%~55%; B2O3: 20%~30%; PbO: 10%~25%; Al2O3: 5%~15%; MgO: 3%~10%; CaO: 0.5%~5%; ZrO2: 0.5%~3%; and clarifying agent: 0%~1%. The encapsulation glass provided by this application has a suitable coefficient of thermal expansion for diode encapsulation and good low-temperature encapsulation performance. This encapsulation glass has long material properties, good wetting with the diode chip during the encapsulation process, tight bonding without cavities, and excellent shape quality, providing high-tightness and high-reliability protection for the diode.

Description

Technical Field

[0001] This application relates to the field of special glass material preparation technology, and in particular to an encapsulation glass, its preparation method and application. Background Technology

[0002] Fast recovery diodes, as core semiconductor devices in modern power electronic systems, play a crucial role in high-end applications such as switching power supplies, variable frequency drives, and new energy power generation due to their extremely short reverse recovery time and extremely low reverse recovery current characteristics. With the rapid development of the electronic information technology industry, power electronic devices are constantly evolving towards miniaturization, high density, and high performance. This trend places more stringent demands on the packaging technology of fast recovery diodes, especially the comprehensive performance of the packaging materials. Excellent packaging materials must ensure the long-term reliability, hermeticity, and good insulation performance of the device, while their process characteristics must be highly compatible with the sensitive chip structure and electrode materials.

[0003] Currently, glass materials are widely used in the packaging of fast recovery diodes due to their excellent insulation, chemical stability, and ideal hermetically sealed performance. However, the sintering temperature of traditional glass materials is relatively high, and this high-temperature process can easily cause thermal damage to the semiconductor chip inside the fast recovery diode, such as thermal defects or performance degradation, directly affecting the yield and long-term reliability of the device. In addition, the properties of traditional glass are poorly compatible with the electrodes; its viscosity-temperature characteristic curve does not match the coefficient of thermal expansion and surface wettability of the electrode material. The "material properties" are too short, resulting in a narrow process window and making it easy to cause packaging defects.

[0004] Therefore, developing a new type of glass packaging material with a lower packaging temperature, better material properties and electrode material matching, and a wider process window is of great significance for improving the packaging quality, production yield and product competitiveness of fast recovery diodes. Summary of the Invention

[0005] The main objective of this application is to provide a packaging glass, its preparation method, and its application. The technical problem to be solved is to provide a packaging glass with low-temperature packaging performance, suitable for diode packaging, with a suitable coefficient of expansion, and with long material properties, good packaging effect, and able to provide high airtightness and high reliability protection for diodes, thus making it more suitable for practical use.

[0006] The objective of this application and the technical problem it solves are achieved by the following technical solution. According to this application, a packaging glass comprises, by way of the molar percentage content of oxides, the following raw material components: SiO2: 40%~55%; B2O3: 20%~30%; PbO: 10%~25%; Al2O3: 5%~15%; MgO: 3%~10%; CaO: 0.5%~5%; ZrO2: 0.5%~3%; Clarifying agent: 0%~1%.

[0007] The purpose of this application and the technical problems to be solved can also be further achieved by the following technical measures.

[0008] Preferably, in the aforementioned encapsulation glass, the coefficient of thermal expansion is 40~50×10⁻⁶ at 25~300°C. -7 / ℃; the transition temperature of the aforementioned encapsulation glass is 480~520℃; the expansion softening temperature of the aforementioned encapsulation glass is 540~600℃.

[0009] The objective of this application and the solution to its technical problem are also achieved by the following technical solution. A method for preparing encapsulating glass according to this application includes the following steps: Prepare the raw materials according to the formula for encapsulating glass, mix them evenly, and obtain the batch material; The aforementioned batch of materials is melted, and mechanical stirring is performed during the melting process to obtain molten glass; The aforementioned molten glass is poured into a mold and then annealed to obtain the aforementioned encapsulated glass; The raw material components of the aforementioned encapsulation glass, based on the molar percentage content of oxides, include: SiO2: 40%~55%; B2O3: 20%~30%; PbO: 10%~25%; Al2O3: 5%~15%; MgO: 3%~10%; CaO: 0.5%~5%; ZrO2: 0.5%~3%; Clarifying agent: 0%~1%.

[0010] The purpose of this application and the technical problems to be solved can also be further achieved by the following technical measures.

[0011] Preferably, in the aforementioned method for preparing the encapsulating glass, the batch material is melted by holding at 1500~1600℃ for 8~10 hours; The mechanical stirring speed is 20~40 rpm; The aforementioned molten glass was cooled to 1100~1200℃ and then poured into shape; The annealing temperature is 500~550℃, and the time is 1~2 hours.

[0012] The purpose of this application and the solution to its technical problem are also achieved by the following technical solution. A packaging glass component according to this application comprises any of the aforementioned packaging glasses.

[0013] The objective of this application and the technical problem it solves are also achieved by the following technical solution. A fast recovery diode according to this application comprises any of the aforementioned encapsulation glasses.

[0014] The purpose of this application and the solution to its technical problem are also achieved by the following technical solution. Based on this application, the aforementioned fast recovery diode is proposed for use in switching, high-frequency rectification, and buffer circuit systems of aerospace vehicles, automotive generators, and high-frequency heating equipment.

[0015] The objective of this application and the solution to its technical problem are also achieved by the following technical solution. According to the method for preparing a packaging glass component proposed in this application, the steps include: Any of the aforementioned encapsulated glass is drilled and rolled to obtain a glass blank tube; The aforementioned glass blank tube is drawn at high temperature to form a fine glass tube; The aforementioned fine glass tube is cut to obtain a packaged glass component.

[0016] The purpose of this application and the technical problems to be solved can also be further achieved by the following technical measures.

[0017] Preferably, in the aforementioned method for preparing the encapsulated glass component, the drill bit speed during drilling is 500-1000 r / min, and the feed rate is 1-3 mm / min; the speed during outer diameter rolling is 150-200 r / min.

[0018] Preferably, in the aforementioned method for preparing the encapsulated glass component, the drawing temperature of the glass blank tube is 750~850℃.

[0019] By employing the above technical solution, the encapsulation glass, its preparation method, and its application of this application have at least the following advantages: (1) This application provides a wide-material packaging glass that has both suitable expansion coefficient and low-temperature packaging properties suitable for diode packaging.

[0020] (2) The encapsulation glass provided in this application has the advantages of good wetting with the diode chip during the encapsulation process, tight bonding without cavity, and excellent shape quality, which can provide high airtightness and high reliability protection for the diode.

[0021] (3) The preparation method of the encapsulation glass provided in this application is simple, easy to control, suitable for large-scale production, applicable to the encapsulation of fast recovery diodes, and provides a new idea for improving the reliability of diode encapsulation.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a thermal expansion curve of the encapsulated glass in Embodiment 1 of this application. Detailed Implementation

[0024] To further illustrate the technical means and effects adopted by this application to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, provides a detailed description of the specific implementation methods, structures, features, and effects of an encapsulation glass and its preparation method based on this application. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0025] The encapsulation glass proposed in this application comprises, by way of the molar percentage content of oxides, the following raw material components: SiO2: 40%~55%; B2O3: 20%~30%; PbO: 10%~25%; Al2O3: 5%~15%; MgO: 3%~10%; CaO: 0.5%~5%; ZrO2: 0.5%~3%; Clarifying agent: 0%~1%.

[0026] Specifically, SiO2 is the main network agglomerate in encapsulated glass. A relatively high SiO2 content acts as an "anchor" for the coefficient of thermal expansion. Although PbO significantly increases the coefficient of thermal expansion, the presence of SiO2 inhibits overall thermal expansion, giving the glass better thermal shock resistance. Higher SiO2 content results in harder glass and higher mechanical strength. However, when the SiO2 content exceeds 55%, the glass melting temperature rises sharply, viscosity increases significantly, energy consumption increases, and bubbles are difficult to remove. If the SiO2 content is below 40%, insufficient network agglomerates lead to an incomplete three-dimensional network structure, poor water and acid resistance, and a tendency for crystallization and phase separation, resulting in short shelf life. Therefore, the SiO2 content is controlled between 40% and 55%.

[0027] B2O3 is the second largest network formant in encapsulated glass. During melting, the [BO3] triangles and the low-polymerization boron oxide groups they form significantly disrupt the continuity of the silicon-oxygen network, greatly reducing the high-temperature viscosity and melting temperature of the glass. [BO4] can tightly bond with the [SiO4] network to form a borosilicate structure with a lower coefficient of thermal expansion, thus significantly improving its thermal shock resistance. If its content exceeds 30%, it will increase the glass's tendency to phase separation, causing the glass to separate into two phases at the microscopic level: a silicon-rich phase and a boron-rich phase, severely impairing its mechanical strength. Excessive B2O3 will lead to the formation of more [BO3] structures, which have poor water resistance and easily lead to a decrease in the glass's hydrolytic stability. If its content is below 20%, it will cause the glass's viscosity-temperature curve to become steeper, the forming temperature range to narrower, and the [BO4] structure to be insufficient, resulting in limited contribution to reducing thermal expansion and failing to achieve optimal thermal shock resistance. Therefore, the B2O3 content should be controlled between 20% and 30%.

[0028] Pb in PbO 2+ PbO, with its large atomic weight and high polarizability, significantly weakens the bond forces of the silicon-oxygen (Si-O) and boron-oxygen (BO) network framework, thereby greatly reducing the melting temperature and high-temperature viscosity of the encapsulation glass. The introduction of PbO makes the glass viscosity-temperature curve exceptionally flat, extending the material's lifespan and providing ample buffer time for the glass melt to contact the electrodes during the encapsulation process. This significantly improves the glass's wettability to the electrodes and the encapsulation's hermeticity, greatly reducing molding difficulty and defect rate. However, if the PbO content exceeds 25%, excessive non-bridging oxygen is introduced, severely disrupting the continuity of the [SiO4] and [BO4] networks, leading to a significant decrease in the glass's acid and water resistance. If the PbO content is below 10%, the glass melting temperature is high, the high-temperature viscosity is large, and homogenization is difficult. The glass viscosity-temperature curve becomes steeper, the molding operation window narrows, and the temperature control requirements are extremely stringent, making it unsuitable for complex molding and prone to cracking and deformation. Therefore, the PbO content is controlled between 10% and 25%.

[0029] Al2O3 effectively reduces the amount of non-bridging oxygen in the encapsulating glass network, making the glass structure denser and stronger. This helps to reduce the high-temperature thermal expansion coefficient to some extent, thus improving thermal shock resistance. When the Al2O3 content exceeds 15%, it significantly increases the glass's melting temperature and high-temperature viscosity, making bubbles and streaks difficult to eliminate. Strong aggregation causes the glass's viscosity-temperature curve to steepen, its thickness to shorten, and its operating window to narrow. It may also promote the precipitation of high-melting-point crystalline phases (such as aluminosilicates), increasing the risk of devitrification and affecting product transparency and uniformity. When the Al2O3 content is below 5%, the glass network becomes relatively loose due to the lack of Al2O3's "reinforcing" effect, resulting in relatively poor water and acid resistance. Therefore, the Al2O3 content should be controlled between 5% and 15%.

[0030] Mg in MgO2+ Ions provide "free oxygen," which can disrupt the silicon-oxygen and boron-oxygen networks in the encapsulated glass, generating non-bridging oxygen and thus reducing the high-temperature viscosity of the glass. Mg 2+ Since MgO ions do not readily exchange with hydrogen ions in water, introducing MgO to replace part of PbO or in synergy with CaO helps improve the water resistance of glass. Due to its aggregation effect, the introduction of MgO can increase the viscosity of glass in the low-temperature range, which helps improve the thermal stability of glass. When the MgO content is higher than 10%, it will drastically increase the tendency of glass to crystallize. The strong aggregation effect of excessive MgO will excessively increase the low-temperature viscosity of glass, causing the glass to become too "short" and may also make the molten glass "thick," which is not conducive to clarification and homogenization. When the MgO content is lower than 3%, its positive regulatory effect on glass structure and properties is negligible, and it cannot effectively contribute to reducing melting temperature, improving chemical stability, and regulating glass properties. Therefore, the MgO content should be controlled between 3% and 10%.

[0031] In the encapsulation glass of this application, the presence of CaO effectively suppresses the precipitation of magnesium silicate crystalline phases (such as enstatite). This is because Ca... 2+ and Mg 2+ When two substances coexist in a structure, they interfere with each other's orderly arrangement into the crystal lattice, thereby improving the glass's resistance to crystallization. An appropriate amount of CaO can improve the glass's water resistance. In this system, due to its low content and synergistic effect with MgO and Al2O3, it generally contributes positively to chemical stability. When the CaO content exceeds 5%, its excessive accumulation effect leads to an overly steep viscosity-temperature curve, significantly shortening the glass's properties; it may also promote the precipitation of calcium-based crystalline phases such as wollastonite (CaSiO3), increasing the risk of devitrification. When the CaO content is below 0.5%, there is insufficient CaO to suppress the crystallization tendency of MgO, and the synergistic effect of CaO and MgO cannot be used for finer adjustments to the glass properties. Therefore, the CaO content is controlled between 0.5% and 5%.

[0032] In the encapsulation glass of this application, ZrO2 can greatly resist the erosion of the silicon-oxygen network by alkaline solutions, while significantly improving the glass's water resistance and acid resistance. When the ZrO2 content is higher than 3%, the molten glass becomes extremely viscous, making it impossible to achieve sufficient melting and clarification, and bubbles and streaks are difficult to remove. ZrO2 itself is a refractory material, and excessive content can easily lead to the precipitation of zirconate microcrystals, causing glass devitrification and severely damaging its uniformity and transparency. When the ZrO2 content is lower than 0.5%, an effective reinforcing phase cannot be formed, and its excellent effect on improving chemical stability and mechanical strength cannot be realized. In systems with high PbO content, if the ZrO2 content is too low, the long-term durability of the glass is at risk. Therefore, the ZrO2 content is controlled between 0.5% and 3%.

[0033] The raw material components of encapsulated glass include 0% to 1% clarifying agent. For example, the clarifying agent can be CeO2. Specifically, as a functional additive, the clarifying agent plays a role in high-temperature clarification during the glass melting process, especially in eliminating difficult-to-remove microbubbles and improving glass quality. The clarifying agent content should not be too high. When the content exceeds 1%, excessive clarifying agent may cause reboiling during the cooling process if the atmosphere is not properly controlled. That is, the dissolved supersaturated oxygen will precipitate again when the glass cools, forming microbubbles, which seriously affects the glass quality.

[0034] Preferably, the coefficient of thermal expansion of the aforementioned encapsulating glass is 40~50×10⁻⁶ at 25~300℃. -7 / ℃; the transition temperature of the aforementioned encapsulation glass is 480~520℃; the expansion softening temperature of the aforementioned encapsulation glass is 540~600℃.

[0035] This application discloses a method for preparing encapsulating glass, the steps of which include: (1) Prepare the raw materials according to the formula of the encapsulated glass, mix them evenly, and obtain the batch material; (2) Melt the aforementioned batch material, and mechanically stir during melting to obtain molten glass; (3) The aforementioned molten glass is cast into a mold and annealed to obtain the aforementioned encapsulated glass; The raw material components of the aforementioned encapsulation glass, based on the molar percentage content of oxides, include: SiO2: 40%~55%; B2O3: 20%~30%; PbO: 10%~25%; Al2O3: 5%~15%; MgO: 3%~10%; CaO: 0.5%~5%; ZrO2: 0.5%~3%; Clarifying agent: 0%~1%.

[0036] In specific implementation, in step (2), the batch material in step (1) is placed in a platinum crucible for heating and melting, and kept at 1500~1600℃ for 8~10h. Mechanical stirring is required during the heating process of the batch material.

[0037] Within the temperature range of 1500~1600℃, the batch material completely transforms into molten glass. Above 1600℃, energy consumption increases, and excessive volatilization of volatile components such as PbO and B2O3 may occur, altering the glass design composition. Below 1500℃, the batch material reacts violently, easily generating a large amount of foam that leads to "overflow," which not only contaminates the furnace but also causes component loss and deviations from the glass composition. At the same time, insufficiently decomposed raw materials are trapped in the melt, forming "scum" and bubbles that are difficult to eliminate.

[0038] To ensure extremely high chemical homogeneity of the molten glass and eliminate streaks and unmelted material, precise mechanical stirring must be applied throughout this stage. For example, initially stir at 40 rpm for 1-2 hours. At this stage, the melt viscosity is relatively high; the purpose of using a higher speed is to generate strong shear force, effectively breaking up initially formed melt clumps, breaking large bubbles, and initially mixing melt streams of different compositions, achieving macroscopic homogenization. Then, reduce the speed to 30 rpm and continue stirring for 2-3 hours. As the temperature rises and the holding period continues, the melt viscosity decreases, and a moderate speed is sufficient to maintain good overall convection, allowing the broken micro-regions to further diffuse and homogenize, while avoiding excessive air entrainment or the formation of micro-eds that are detrimental to clarification due to excessively high speed. Finally, reduce the speed to 20 rpm and stir for another 2-3 hours. At the end of the homogenization period, using a low speed aims to maintain slight melt movement, prevent local component segregation, and create a relatively quiet environment conducive to the merging, growth, and upward displacement of small and medium-sized bubbles, creating favorable conditions for subsequent clarification. This "high-medium-low" variable-speed stirring strategy is key to achieving high glass homogenization. If the stirring speed is too high or the stirring time is too long, the strong eddies will engulf tiny bubbles deep into the melt, causing them to disperse too finely and making it difficult for them to coalesce, grow, and float, which is detrimental to clarification. At the same time, high-speed stirring will exacerbate the erosion of the stirring paddle and crucible, introducing impurities. If the stirring speed is too low or there is no stirring, melt homogenization relies entirely on natural convection, which is extremely inefficient and will lead to severe chemical inhomogeneity (stripes) and thermal inhomogeneity, resulting in a significant decrease in glass quality and failure to meet the requirements of optical packaging applications.

[0039] In specific implementation, in step (3), the fully melted, homogenized and clarified glass melt is poured into shape through a precision sprue located at the bottom of the platinum crucible. Then, the poured glass material is quickly transferred to a precision annealing furnace preheated to 500~550℃ and kept warm and slowly cooled according to a specific annealing curve.

[0040] The discharge temperature is 1100~1200℃. This temperature range corresponds to the ideal forming window for the viscosity of this glass system. At this viscosity, the molten glass has good fluidity, ensuring a stable and continuous flow from the drain. Simultaneously, its cohesion and surface tension are sufficient to maintain the shape of the glass column, preventing flow interruption or excessive spreading. This perfectly utilizes the "long-lasting" characteristics of PbO and B2O3 in this system, meaning the viscosity changes slowly with temperature. This makes the forming process insensitive to temperature fluctuations, with high process tolerance, and facilitates obtaining profiles with uniform dimensions. If the discharge temperature exceeds 1200℃, the viscosity of the molten glass is too low, the flow rate is too fast, and it is difficult to control stably, easily causing dimensional deviations in the profiles (such as diameter fluctuations). Excessively high temperatures significantly accelerate the volatilization of volatile components such as PbO and B2O3. At excessively low viscosity, the formed glass profile is more prone to plastic deformation under its own weight, making it difficult to maintain a regular geometric shape. If the leakage temperature is below 1100℃, the viscosity of the molten glass increases sharply, leading to poor flow, uneven particle size, or even flow interruption, making continuous production impossible. At the same time, the melt easily enters its crystallization temperature range, and components such as ZrO2 readily act as crystal nuclei, inducing large-scale crystal growth, resulting in product devitrification and complete loss of the optical uniformity and mechanical integrity required as an encapsulation material.

[0041] Precision annealing effectively reduces internal stress in glass materials. The temperature range of 500~550℃ precisely corresponds to the glass transition temperature (Tg) region of this glass system. In this system, SiO2, [BO4] tetrahedra, and Al2O3 form a robust three-dimensional network, tending to increase Tg; while a large amount of PbO, as a network modifier, introduces non-bridging oxygen, lowering Tg. The final compositional equilibrium results in a Tg of approximately 500℃. Holding at this temperature allows the atoms and molecular chains within the glass to gain sufficient mobility, enabling the permanent internal stress caused by rapid and uneven cooling to be fully relaxed through viscous flow. When the annealing temperature exceeds 550℃, the viscosity of the glass drops to near its softening point, and plastic deformation occurs under its own gravity, leading to profile warping, collapse, and dimensional deviations. Excessively high annealing temperatures are equivalent to prolonged heat treatment within the crystallization peak temperature range, which greatly promotes the growth of crystals such as MgO-CaO silicates or zirconates, resulting in product devitrification and performance degradation. When the annealing temperature is below 500℃, the temperature is too low, the atomic / molecular chain segments lack mobility, and the internal stress cannot be effectively relaxed. High residual stress remains inside the product after annealing. Glass products with high residual stress are highly susceptible to spontaneous cracking due to stress release during storage, transportation, or subsequent processing (such as drilling or cutting).

[0042] This application provides a packaging glass component comprising any of the aforementioned packaging glasses.

[0043] This application discloses a fast recovery diode comprising any of the aforementioned encapsulation glasses.

[0044] This application proposes the application of the aforementioned fast recovery diode in switching, high-frequency rectification, and buffer circuit systems of aerospace vehicles, automotive generators, and high-frequency heating equipment.

[0045] This application discloses a method for preparing a sealing glass component, the steps of which include: Any of the aforementioned encapsulated glass is drilled and rolled to obtain a glass blank tube; preferably, the drill bit speed during drilling is 500~1000 r / min and the feed rate is 1~3 mm / min; the speed during rolling is 150-200 r / min.

[0046] The aforementioned glass blank tube is drawn at high temperature to form a fine glass tube; preferably, the drawing temperature of the glass blank tube is 750~850℃.

[0047] The aforementioned fine glass tube is cut to obtain a packaged glass component.

[0048] The present application will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present application are still within the scope of protection of the present application.

[0049] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. Example 1

[0050] The raw materials for the encapsulation glass are prepared according to the formula and mixed evenly to obtain the batch material. The raw material components of the encapsulation glass, based on the molar percentage of oxides, include: 45% silicon dioxide, 25% boron trioxide, 15% lead oxide, 8% aluminum oxide, 3% magnesium oxide, 2% calcium oxide, 1.5% zirconium oxide, and 0.5% cerium oxide, wherein the mass of silicon dioxide is 200g, and the masses of the others are correspondingly equal.

[0051] The batch material was placed in a high-temperature furnace and melted at 1600℃ with mechanical stirring. Stirring was performed at 40 rpm for 2 hours, then at 30 rpm for 3 hours, and finally at 20 rpm for 3 hours to ensure uniform distribution of glass powder. After stirring was stopped, the mixture was allowed to stand for 2 hours to allow air bubbles in the molten glass to escape smoothly. The total melting time was 10 hours. The furnace temperature was then lowered to 1200℃, and the mixture was cast into shape using a pouring method. Annealing was then performed at 520℃ for 2 hours to obtain the encapsulated glass. The coefficient of thermal expansion, transition temperature, and softening temperature of the encapsulated glass were tested between 25 and 300℃, and the results are shown in Table 1. The thermal expansion curve of the encapsulated glass is shown in [Table 1]. Figure 1 .

[0052] The encapsulation glass is fixed on the base of a drilling lathe, and a hole is drilled in the glass using a drill bit with a diameter of 26 mm and a thickness of 1.8 mm at a speed of 800 r / min and a feed rate of 2 mm / min. The drilled glass material is then fixed in an external cylindrical grinder and rolled at a speed of 200 r / min to obtain a glass blank tube. The glass blank tube is then drawn at 850℃ in a drawing furnace to obtain fine glass filaments, which are then cut to obtain the encapsulation glass parts.

[0053] Example 2-15 The difference between Examples 2-15 and Example 1 is that the proportions of each component in the raw materials of the encapsulation glass in Examples 2-15 are different from those in Example 1, as shown in Tables 1-3. The remaining steps and parameters are the same as in Example 1.

[0054] The coefficient of thermal expansion, transition temperature, and expansion softening temperature of the encapsulated glass in Examples 2-15 were tested at 25~300℃. The results are shown in Tables 1-3.

[0055] Comparative Examples 1-3 The difference between Comparative Examples 1-3 and Example 1 is that the proportions of each component in the raw materials of the glass in Comparative Examples 1-3 are different from those in the raw materials of the encapsulated glass in Example 1, as shown in Table 3. The remaining steps and parameters are the same as in Example 1.

[0056] The coefficient of thermal expansion, transition temperature, and expansion softening temperature of the glass in Comparative Examples 1-3 were tested at 25~300℃, and the results are shown in Table 3.

[0057] Table 1. Raw material composition ratios of the encapsulation glass in Examples 1-7

[0058] Table 2. Raw material composition ratios of the encapsulation glass in Examples 8-14

[0059] Table 3. Raw material composition ratios of the encapsulation glass in Example 15 and the glasses in Comparative Examples 1-3.

[0060] As can be seen from the data in the table above, in Examples 1-15 of the present invention, due to the synergistic regulatory effect of elements such as Pb, B, Mg, and Ca in the components, the linear expansion coefficient of the glass material is controlled within 40~50×10⁻⁶. -7 Within a certain temperature range, the expansion coefficient is well matched with the expansion characteristics of the tungsten electrode used in fast recovery diodes. If the expansion coefficient exceeds this range, stress will be generated between the glass and the tungsten electrode due to thermal expansion mismatch, which may lead to package cracking or seal failure, affecting device reliability. In addition, the difference between the transition point and softening point of the glass in the embodiment is in the range of 50~70℃, indicating that the glass has a wide material flexibility characteristic, which can meet the requirements of fast recovery diode packaging process. If the material flexibility is too short, the glass melt has insufficient fluidity at the packaging temperature, making it difficult to fully fill the gap between the chip and the glass shell, easily leaving cavities, affecting the device's hermeticity and chip performance; conversely, if the material flexibility is too long, the glass deformation is too large under the same process conditions, and the outer side of the glass material deforms more, which is not conducive to subsequent device assembly.

[0061] According to a specific embodiment of the present invention, through comparative analysis of Example 1 and various comparative examples, the key influence of each process element on the applicability of glass material encapsulation was fully verified. Specifically, the PbO content in Comparative Example 1 was 30%, exceeding the preferred range of 10% to 25% of the present invention. Excessive PbO acts as a strong network outer layer, and its Pb content... 2+ Ions excessively disrupt the silicon-oxygen and boron-oxygen network framework, leading to a significant decrease in the degree of polymerization of the glass network and a looser structure. The results are shown in the table, with an expansion coefficient of 4.96 × 10⁻⁶. -6 At a temperature of / ℃, the expansion difference between the glass material and the tungsten electrode exceeds 10%, which exacerbates the thermal expansion mismatch between the glass material and the tungsten electrode. During cooling, this difference in contraction leads to excessive residual stress. This stress is the root cause of microcracks and even macroscopic cracking in diode devices during operation, severely reducing package reliability and device lifespan. In Comparative Example 2, the Al2O3 content is 20%, exceeding the preferred range of 5%~15% of this invention, indicating excessive Al content. 3+The ions mainly exist in the form of [AlO4] tetrahedra in the structure and strongly tend to form a robust and highly cross-linked aluminosilicate network with [SiO4] tetrahedra. This over-densification and highly polymerized network structure leads to a sharp increase in the high-temperature viscosity of the glass melt, and the viscosity decreases at a significantly faster rate with temperature. As shown in Table 3, the difference between the expansion softening point and the transformation point of Comparative Example 2 is 49.9℃, and the material properties are significantly shortened. The B2O3 content in Comparative Example 3 is 18%, which is lower than the preferred range of 20-30% of this invention. When its content is insufficient, the glass network mainly relies on SiO2 and some Al2O3 to form a rigid silicon (aluminum) oxide framework, while the [BO3] / [BO4] structural units, which can effectively increase the network deformation capacity and broaden the softening temperature range, are relatively insufficient. The specific macroscopic performance is shown in the table. The difference between the expansion softening point and the transformation point of Comparative Example 3 is 49.3℃, indicating that the material is significantly shorter. At the packaging temperature, the glass melt has insufficient fluidity, making it difficult to fully fill the gap between the chip and the glass shell, which easily leaves cavities and affects the device's airtightness and chip performance.

[0062] The technical features in the claims and / or specification of this application can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this application.

[0063] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A type of encapsulation glass, characterized in that, Its raw material components, expressed as a molar percentage of oxides, include: SiO2: 40%~55%; B2O3: 20%~30%; PbO: 10%~25%; Al2O3: 5%~15%; MgO: 3%~10%; CaO: 0.5%~5%; ZrO2: 0.5%~3%; Clarifying agent: 0%~1%.

2. The encapsulation glass according to claim 1, characterized in that, The coefficient of thermal expansion of the encapsulating glass is 40~50×10⁻⁶ at 25~300℃. -7 / ℃; The transition temperature of the encapsulation glass is 480~520℃; The expansion and softening temperature of the encapsulation glass is 540~600℃.

3. A method for preparing encapsulating glass, characterized in that, The steps include: Prepare the raw materials according to the formula for encapsulating glass, mix them evenly, and obtain the batch material; The batch material is melted, and mechanical stirring is performed during the melting process to obtain molten glass; The molten glass is cast into a shape and then annealed to obtain the encapsulated glass; The raw material composition of the encapsulation glass, based on the molar percentage of oxides, includes: SiO2: 40%~55%; B2O3: 20%~30%; PbO: 10%~25%; Al2O3: 5%~15%; MgO: 3%~10%; CaO: 0.5%~5%; ZrO2: 0.5%~3%; Clarifying agent: 0%~1%.

4. The preparation method according to claim 3, characterized in that, The batch material is melted by holding at 1500~1600℃ for 8~10 hours; The mechanical stirring speed is 20~40 rpm; The molten glass is cooled to 1100~1200℃ and then poured into shape; The annealing temperature is 500~550℃, and the time is 1~2 hours.

5. A type of encapsulated glass component, characterized in that, It comprises the encapsulation glass as described in any one of claims 1-2.

6. A fast recovery diode, characterized in that, It comprises the encapsulation glass as described in any one of claims 1-2.

7. The application of the fast recovery diode as described in claim 6 in the switching, high-frequency rectification and buffer circuit systems of aerospace vehicles, automotive generators, and high-frequency heating equipment.

8. A method for preparing a glass encapsulation component, characterized in that, The steps include: The encapsulation glass according to any one of claims 1-2 is drilled and rolled on the outer circle to obtain a glass blank tube; The glass blank tube is drawn at high temperature to form a fine glass tube; The glass fine tube is cut to obtain a packaged glass component.

9. The method for preparing the encapsulated glass component according to claim 8, characterized in that, When drilling, the drill bit rotates at 500-1000 r / min and the feed rate is 1-3 mm / min; The rotational speed during outer diameter rolling is 150-200 r / min.

10. The method for preparing the encapsulated glass component according to claim 8, characterized in that, The drawing temperature of the glass blank tube is 750~850℃.

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