Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as well as preparation method and application thereof

Abstract

The invention discloses Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as well as a preparation method and application of the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass. The Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass is prepared from the following raw material components in percentage by weight: 6 to 12 percent of SiO2, 3 to 5 percent of Al2O3, 4 to 7 percent of Na2O, 1 to 4 percent of ZrO2, 10 to 20 percent of B2O3, 10 to 22 percent of ZnO and 48 to 60 percent of Bi2O3. Through component regulation and control and heat treatment process optimization, on one hand, the sintering temperature is reduced to 500-650 DEG C, and the structural integrity of the resistive layer is guaranteed; on the other hand, the thermal expansion coefficient is stabilized at 7.8-8.5 * 10 <-6 > / DEG C, the matching degree with a ruthenium resistance layer is improved to 90% or above, and the interface internal stress and the thermal cycle cracking risk are greatly reduced; furthermore, the wetting angle of the obtained glass molten slurry is small, the glass molten slurry can fully extend on the surface of the resistive layer, the defect of incomplete coverage of traditional encapsulation is overcome, and the thickness uniformity of the encapsulation layer is ensured; the prepared packaging layer has high electrical insulativity, high air tightness, strong chemical stability and small internal stress, can stably serve for a long time in a high-temperature environment, and is suitable for the fields of resistors, automotive electronics, sensors and the like with high reliability requirements.

Description

Technical Field

[0001] This invention belongs to the field of functional materials, and relates to electronic packaging glass, specifically to a Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass, its preparation method, and its application. Background Technology

[0002] As automotive electronics, 5G communications, and high-end sensors rapidly evolve towards miniaturization, high power density, and high reliability, the operating environments for thick-film resistors are becoming increasingly complex. In scenarios such as automotive engine compartments, 5G base station RF modules, and industrial automation sensors, they must continuously withstand the multiple effects of sudden temperature changes, electric field stress, and moisture corrosion. Thick-film resistors, with their outstanding advantages such as high temperature resistance, low temperature coefficient of resistance, high power density, and wide resistance range, are well-suited for applications in these fields. Therefore, they are widely used in critical scenarios such as the automotive industry, communication equipment, PLC controllers, and precision instruments, becoming a core component ensuring the stable operation of electronic systems.

[0003] Statistical data shows that approximately 50% of electronic equipment failures originate from resistor failure, with environmental corrosion being the primary cause. Under harsh conditions of high temperature and humidity, and corrosive gases such as SO2 / H2S, the metal film layer of ruthenium-based resistors is highly susceptible to electrochemical corrosion, ultimately leading to resistor failure. To fundamentally solve this problem and ensure the long-term reliable operation of ruthenium-based resistors, encapsulation materials are needed to fully protect the resistive layer. Compared to traditional polymer and metal encapsulation materials, glass pastes, due to their excellent electrical insulation, hermeticity, and chemical inertness, have become the preferred choice for encapsulating ruthenium-based resistors. An ideal encapsulating glass needs to be able to flow sufficiently and completely wet the resistive film and substrate at a relatively low sintering temperature, while also ensuring thermal expansion compatibility with the resistive layer and its own chemical stability, thus preventing encapsulation failure due to glass layer cracking and aging during service.

[0004] Patent document EP0711255B1 discloses an encapsulation glass based on PbO-B2O3-SiO2 lead borosilicate glass, which fully encapsulates the metal conductor and resistive film within a temperature range of 600-700℃, meeting the basic requirements of traditional packaging. However, the toxicity and environmental risks of Pb element seriously conflict with environmental regulations such as RoHS, becoming a bottleneck for the application of this system.

[0005] Patent document CN202111067362.9 discloses related encapsulated glass-ceramic slurry, thin-film platinum resistance temperature sensor, and their preparation methods. Experiments have shown that the encapsulated glass-ceramic prepared by this method exhibits good chemical stability, electrical insulation, glass softening temperature, and thermal shock resistance. However, the encapsulated glass-ceramic slurry prepared by this method, when sintered at 920-950 ℃, easily causes the ruthenium-based thick-film resistive layer to volatilize.

[0006] Patent document CN202010867257.2 discloses a lead-free low-temperature sintering encapsulating glass paste and its preparation method, describing a lead-free low-temperature sintering encapsulating glass paste. However, the encapsulated glass prepared by this method has poor chemical stability.

[0007] Bi₂O₃-based lead-free glass generally suffers from difficulties in achieving thermal expansion matching with the resistive layer, especially for ruthenium-based thick-film resistors, where the coefficient of thermal expansion of the resistive layer is 8.5 × 10⁻⁶. -6 / ℃, requiring the difference between the thermal expansion coefficient of the encapsulation material and its coefficient of thermal expansion to not exceed 1×10 -7 / ℃, otherwise the internal stress generated during thermal cycling will directly cause the encapsulation layer to crack.

[0008] Based on the deficiencies of the prior art, the present invention provides a Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass powder, which specifically solves the encapsulation technical problem of ruthenium-based thick film resistors. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass, its preparation method, and its applications. This glass melt has low surface tension, good fluidity, wettability, and processing performance, and a low sintering temperature. The prepared electronic packaging layer has high chemical stability and matches the thermal expansion coefficient of ruthenium-based thick film resistivity. The preparation process is simple, low-cost, and suitable for industrial production.

[0010] To achieve the above objectives, the present invention employs the following technical solution: A Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass, the raw material composition includes: SiO2 6~12wt%, Al2O3 3~5wt%, Na2O 4~7wt%, ZrO2 1~4wt%, B2O3 10~20wt%, ZnO 10~22wt%, Bi2O3 48~60wt%.

[0011] This invention also protects a method for preparing the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described above, comprising the following steps: Step 1: Weigh the raw materials according to the weight ratio and put them into a V-type mixer. Mix for 40-60 minutes until the mixture is uniform and forms a mixture. Step 2: Add the mixture to the quartz crucible of the crucible furnace and keep it at 1030~1150 ℃ for 3~5 h to obtain glass melt; Step 3: Quickly pour the molten glass into deionized water for water quenching to obtain glass slag. After multi-stage ball milling, dry and sieve the glass slag to obtain glass powder. Step 4: Prepare glass powder into a slurry, screen print it onto the surface of the resistor, and sinter it in a muffle furnace at 500~650 ℃ in an air atmosphere, then cool it to obtain Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass.

[0012] Preferably, the multi-stage ball milling described in step three is as follows: Glass slag is placed together with an equal mass of agate balls with a particle size of 8-15 mm into an agate jar and ground in a ball mill at 280-320 rpm for 25-40 minutes to obtain coarse glass powder with a D50 particle size of 20-30 micrometers. By weight, 1 part coarse glass powder, 3 parts 2-5 mm agate spheres, and loose deionized water are placed in an agate jar and ground in a ball mill at 400-450 rpm for 60-120 minutes to obtain wet glass powder with a D50 particle size of 1.0-2.0 micrometers.

[0013] Preferably, the drying in step three involves drying the spheroidized wet glass powder at 120°C.

[0014] Preferably, the sieving in step three involves passing the dried sample through a 150-200 mesh sieve.

[0015] This invention also protects the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass prepared by the above method, with a coefficient of thermal expansion of 7.8~8.5×10⁻⁶. -6 / ℃.

[0016] The present invention also protects the application of the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described above in ruthenium-based thick film resistor packaging.

[0017] Compared with the prior art, the present invention has the following technical effects: The Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass of this invention, through composition control and optimized heat treatment process, achieves two main advantages: First, the sintering temperature is reduced to 500~650℃, far below the oxidation temperature of ruthenium-based resistor layers. This avoids the high-temperature oxidation and volatilization of RuO2 when used for ruthenium-based thick-film resistor packaging, preventing resistance drift, electrode detachment, or substrate cracking during sintering and ensuring the structural integrity of the resistor layer. Second, its coefficient of thermal expansion is stabilized at 7.8~8.5×10⁻⁶. -6 / ℃, with a ruthenium-based resistive layer of 8.0~8.5×10 -6The matching degree at / ℃ is improved to over 90%, significantly reducing the risk of interfacial internal stress and thermal cycling cracking. Furthermore, the prepared Bi2O3-B2O3-ZnO-SiO2 glass molten slurry has a small wetting angle and excellent fluidity, which can be fully extended on the surface of the resistor layer, solving the defect of "incomplete coverage" in traditional encapsulation and ensuring the uniformity of the encapsulation layer thickness. The prepared encapsulation layer has high electrical insulation, high hermeticity, strong chemical stability, and low internal stress, and can be stably used for a long time in high-temperature environments. It is suitable for fields with high reliability requirements such as resistors, automotive electronics, and sensors. The above advantages are attributed to the fact that, in the Bi2O3-B2O3-ZnO-SiO2 glass raw material composition of the present invention, B... i2 O3 is connected by alternating [BiO6] octahedra and [BiO3] triangular prisms, forming the basic network structure of the glass. The Bi-O bond energy is much lower than that of the Si-O bond, and it breaks preferentially upon heating, reducing the glass melt viscosity to 102~103 Pa. The overall melting temperature is as low as 600-800 ℃, which supports the excellent fluidity of the slurry and low-temperature sintering; the high atomic weight of Bi makes the glass density reach 6.0~6.5 g / cm³. 3 After sintering, the density easily exceeds 98%, which can effectively block the penetration channels of water vapor and corrosive gases, ensuring the encapsulation and protection effect. Bi2O3 and B2O3 together act as glass network precursors, forming a synergistic effect—both further reducing the glass transition temperature and softening temperature, and simultaneously improving the glass's resistance to water and acid leaching, ultimately achieving a balance between "lower sintering temperature" and "high density and high chemical stability"; increasing the Bi2O3 content within a reasonable range can further enhance its low-temperature flow properties without affecting the long-term reliability of the glass. SiO2 is a traditional glass network forger, using [SiO4] tetrahedra as its basic unit. It forms a highly polymerized network structure through Si-O-Si bridging oxygen bonds. The Si-O bonds are very strong, forming a robust and stable three-dimensional network structure, giving the glass excellent stability. However, excessive SiO2 significantly increases the melting temperature and melt viscosity. Adding a small amount of SiO2 ensures that the glass retains basic strength, hardness, and corrosion resistance after solidification, preventing the glass from becoming too soft or unstable. It also helps build the framework of the glass network, providing mechanical strength and chemical stability. B2O3, by breaking Si–O–Si bonds and generating non-bridging oxygen (NBO), significantly lowers the glass transition temperature and melting temperature, allowing the glass to maintain a wide "processable viscosity window" in the medium and low temperature range. Adding a small amount to the system avoids the problem of insufficient mechanical strength caused by Bi2O3, improves the flexural strength of the glass, and enhances acid resistance. However, excessive amounts will cause the glass melting temperature to rise, impairing low-temperature fluidity. Boric acid transforms into boron oxide (B2O3) upon heating. It is a glass-forming material that constructs a glass network through [BO3]. The addition of B2O3 can significantly reduce the coefficient of thermal expansion of glass, making it less prone to cracking during heating and cooling. This is crucial for coating slurries that need to be sealed with other materials (matching the coefficient of thermal expansion). Adjusting the B2O3 content allows the glass transition temperature (Tg) and softening temperature (Ts) of the glass to be adjusted within the range of 450-500 ℃, thereby significantly affecting sintering densification and melt flow behavior. It works synergistically with Bi2O3 to further reduce the melting point while improving the chemical durability of the glass. ZnO is an intermediate oxide that cannot form glass on its own, but it can be incorporated into the SiO2-B2O3 network; Zn 2+ Can replace part of Si 4+ Or B 3+ It enters the network gaps, forming [ZnO4] tetrahedra, promoting the transformation of [BO3]→[BO4], and forming more [BO4] / [ZnO4] structural units. This moderately reduces viscosity and adjusts the coefficient of thermal expansion while maintaining close packing and high chemical stability. It avoids the decrease in chemical stability caused by excessive network breakage and does not increase melt viscosity. It can improve the chemical stability of glass, making it more resistant to water and acid corrosion, and also helps to reduce the coefficient of thermal expansion. Na₂O, as a typical network modifier, plays a crucial role in breaking down the glass network structure to optimize processing performance: Na₂O is generated by the thermal decomposition of sodium carbonate. + As an external ion in the network, it can insert into the gaps in the [SiO4] or [BiO6] structure, directly breaking the Si-O-Si and Bi-O-Bi bridging oxygen bonds, reducing the melting temperature and high-temperature viscosity of the glass, and achieving low-temperature sintering of the slurry; however, excessive addition of Na2O will lead to excessive breakage of the glass network, reducing water resistance, weakening chemical stability and mechanical strength. Al2O3, as a glass network intermediate, when added in small amounts, Al... 3+ It can be embedded in the vacancies formed by the fractured network of Na2O to form [AlO4] / [AlO6] coordination polyhedra, which improves the cross-linking degree of the glass network, so that the glass can flow fully to complete the coating near the sintering temperature without collapsing due to excessive softening; it significantly improves the chemical stability, mechanical strength and thermal stability of the glass, while enhancing the anti-crystallization ability and offsetting the negative effects of Na2O. Due to its high electric field strength and chemical inertness, ZrO2 can significantly enhance the structural density of the glass network and improve its resistance to corrosion by alkaline substances, even when added in low concentrations. It can also improve the hardness and wear resistance of the glass. Under long-term electric field loading or temperature cycling conditions, it maintains the structural stability of the interface between the ruthenium-based resistive film and the coated glass, preventing interface delamination or performance degradation. The electronic packaging glass of this invention uses glass powder that has passed through a 150-200 mesh sieve and is wet-printed onto the surface of a resistor. The glass paste is a paste-like fluid that can completely wet the surface of the resistor during printing and fill the tiny gaps between the resistor body and the electrodes. After sintering, the glass layer forms a dense, non-porous coating layer with the surface of the resistor, which can effectively isolate external moisture, dust, and corrosive gases, and prevent the internal components of the resistor from oxidizing or becoming damp and failing. The preparation process of Bi2O3-B2O3-ZnO-SiO2 glass powder of the present invention is simple, requires little equipment investment, and is inexpensive, enabling mass production and making it suitable for large-scale enterprise implementation. Attached Figure Description

[0018] Figure 1 The wetting angle spectra of the encapsulated glass obtained in Examples 1, 2, 3, 4, and 5 are shown. Figure 2 This is a scanning electron microscope image of the glass encapsulation layer obtained in Example 3; Figure 3 The thermal expansion curve of the glass encapsulation layer obtained in Example 3; Figure 4 The spread radius diagrams of the glass encapsulation layers prepared in Examples 1, 2, 3, and 4 are shown. Detailed Implementation

[0019] The following detailed explanation of the specific content of the present invention is provided in conjunction with embodiments. These descriptions are intended to explain the present invention and not to limit it.

[0020] Example 1: This embodiment provides a method for preparing the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described above, including the following steps: Step 1: Weigh the raw materials according to the following weight ratio: 8 wt% quartz sand, 3 wt% alumina, 5 wt% sodium carbonate, 2 wt% zirconium oxide, 11 wt% boric acid, 22 wt% zinc oxide, and 49 wt% bismuth oxide. Place them in a V-type mixer and mix for 60 minutes until the mixture is homogeneous, forming a mixture. Step 2: Add the mixture to the quartz crucible of the crucible furnace and keep it at 1100 ℃ for 3 h to obtain glass melt; Step 3: Quickly pour the molten glass into deionized water for water quenching to obtain glass slag. Put the glass slag and an equal mass of agate balls with a particle size of 10 mm into an agate jar and grind them in a ball mill at 300 revolutions per minute for 30 minutes to obtain coarse glass powder with a D50 particle size of 20-30 micrometers. By weight, 1 part coarse glass powder, 3 parts 3mm agate pebbles, loose powder and deionized water were placed in an agate jar and ground in a ball mill at 400 rpm for 60 minutes to obtain glass powder with a D50 particle size of 1.0-2.0 micrometers. The spherical-milled wet glass powder was dried at 120℃ for 4 hours and finally passed through a 200-mesh sieve to obtain the finished product. Step 4: Weigh 23g of terpineol, pour it into a beaker, and place it on a heated magnetic stirrer. Weigh 0.75g of ethyl cellulose M70 and add it to the magnetically stirred terpineol in small amounts several times. Initially, it will be a turbid solution. As the stirring continues, the solution will gradually become clear. Continue heating to 100°C. After it becomes uniform, let it stand and cool. Then add 0.8g of Span-85 and continue stirring. After it is uniformly stirred, an organic carrier for electronic paste is prepared. Then seal and store it. Weigh 17 g of the glass powder prepared above and add it to a mortar. Pour in 9 g of the sealed organic carrier and stir until it becomes a paste. Then pour it into a three-roll mill for stirring and dispersion. Pour the slurry into the three-roll mill, roll it three times with the coarse roller until the large particles are dispersed, then roll it three times with the fine roller until the slurry becomes completely paste-like and can flow slowly. This indicates that it is mixed evenly. Seal and store the evenly mixed slurry until it is ready for use. Using screen printing, an encapsulating glass paste was coated onto an alumina substrate with a ruthenium resistive film deposited on it, resulting in a ruthenium-based thick-film resistor. The encapsulating glass paste was sintered in air at 650°C for 30 minutes and then cooled to obtain Bi₂O₃-B₂O₃-ZnO-SiO₂ electronic packaging glass. The coefficient of thermal expansion of the encapsulated microcrystalline glass was 8.4 × 10⁻⁶. -6 / ℃, insulation resistivity greater than 10 14 Ω·cm, water resistance is grade I.

[0021] Example 2: This embodiment provides a method for preparing the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described above, including the following steps: Step 1: Weigh the raw materials according to the following weight ratio: 6 wt% quartz sand, 3 wt% alumina, 7 wt% sodium carbonate, 1 wt% zirconium oxide, 10 wt% boric acid, 22 wt% zinc oxide, and 51 wt% bismuth oxide. Place them in a V-type mixer and mix for 50 minutes until the mixture is uniform, forming a mixture. Step 2: Add the mixture to the quartz crucible of the crucible furnace and heat it at 1080 ℃ for 4 h to obtain glass melt; Step 3: Quickly pour the molten glass into deionized water for water quenching to obtain glass slag. Put the glass slag and an equal mass of agate balls with a particle size of 8 mm into an agate jar and grind them in a ball mill at 320 revolutions per minute for 25 minutes to obtain coarse glass powder with a D50 particle size of 20-30 micrometers. By weight, 1 part coarse glass powder, 3 parts 2mm agate pebbles, loose powder and deionized water were placed in an agate jar and ground in a ball mill at 400 rpm for 120 minutes to obtain glass powder with a D50 particle size of 1.0-2.0 micrometers. The spherical-milled wet glass powder was dried at 120℃ for 6 hours and finally passed through a 150-mesh sieve to obtain the finished product. Step 4: Weigh 23g of terpineol, pour it into a beaker, and place it on a heated magnetic stirrer. Weigh 0.75g of ethyl cellulose M70 and add it to the magnetically stirred terpineol in small amounts several times. Initially, it will be a turbid solution. As the stirring continues, the solution will gradually become clear. Continue heating to 100°C. After it becomes uniform, let it stand and cool. Then add 0.8g of Span-85 and continue stirring. After it is uniformly stirred, an organic carrier for electronic paste is prepared. Then seal and store it. Weigh 17 g of the glass powder prepared above and add it to a mortar. Pour in 9 g of the sealed organic carrier and stir until it becomes a paste. Then pour it into a three-roll mill for stirring and dispersion. Pour the slurry into the three-roll mill, roll it three times with the coarse roller until the large particles are dispersed, then roll it three times with the fine roller until the slurry becomes completely paste-like and can flow slowly. This indicates that it is mixed evenly. Seal and store the evenly mixed slurry until it is ready for use. Using screen printing, an encapsulating glass paste was coated onto an alumina substrate with a ruthenium resistive film deposited on it, resulting in a ruthenium-based thick-film resistor. The encapsulating glass paste was sintered in air at 550°C for 30 minutes and then cooled to obtain Bi₂O₃-B₂O₃-ZnO-SiO₂ electronic packaging glass. The coefficient of thermal expansion of the encapsulated microcrystalline glass was 8.4 × 10⁻⁶. -6 / ℃, insulation resistivity greater than 10 14 Ω·cm, water resistance is grade I.

[0022] Example 3: This embodiment provides a method for preparing the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described above, including the following steps: Step 1: Weigh the raw materials according to the following weight ratio: 12 wt% quartz sand, 5 wt% alumina, 4 wt% sodium carbonate, 4 wt% zirconium oxide, 17 wt% boric acid, 10 wt% zinc oxide, and 48 wt% bismuth oxide. Place them in a V-type mixer and mix for 40 minutes until the mixture is uniform, forming a mixture. Step 2: Add the mixture to the quartz crucible of the crucible furnace and heat it at 1030 °C for 5 hours to obtain molten glass; Step 3: Quickly pour the molten glass into deionized water for water quenching to obtain glass slag. Put the glass slag and an equal mass of agate balls with a particle size of 15 mm into an agate jar and grind them in a ball mill at 280 revolutions per minute for 40 minutes to obtain coarse glass powder with a D50 particle size of 20-30 micrometers. By weight, 1 part coarse glass powder, 3 parts 2mm agate pebbles, loose powder and deionized water were placed in an agate jar and ground in a ball mill at 450 rpm for 80 minutes to obtain glass powder with a D50 particle size of 1.0-2.0 micrometers. The spherical-milled wet glass powder was dried at 120℃ for 8 hours and finally passed through a 180-mesh sieve to obtain the finished product. Step 4: Weigh 23g of terpineol, pour it into a beaker, and place it on a heated magnetic stirrer. Weigh 0.75g of ethyl cellulose M70 and add it to the magnetically stirred terpineol in small amounts several times. Initially, it will be a turbid solution. As the stirring continues, the solution will gradually become clear. Continue heating to 100°C. After it becomes uniform, let it stand and cool. Then add 0.8g of Span-85 and continue stirring. After it is uniformly stirred, an organic carrier for electronic paste is prepared. Then seal and store it. Weigh 17 g of the glass powder prepared above and add it to a mortar. Pour in 9 g of the sealed organic carrier and stir until it becomes a paste. Then pour it into a three-roll mill for stirring and dispersion. Pour the slurry into the three-roll mill, roll it three times with the coarse roller until the large particles are dispersed, then roll it three times with the fine roller until the slurry becomes completely paste-like and can flow slowly. This indicates that it is mixed evenly. Seal and store the evenly mixed slurry until it is ready for use. Using screen printing, an encapsulating glass paste was coated onto an alumina substrate with a ruthenium resistive film deposited on it, resulting in a ruthenium-based thick-film resistor. The encapsulating glass paste was sintered in air at 550°C for 30 minutes and then cooled to obtain Bi₂O₃-B₂O₃-ZnO-SiO₂ electronic packaging glass. The coefficient of thermal expansion of the encapsulated microcrystalline glass was 8.42 × 10⁻⁶. -6 / ℃, insulation resistivity greater than 10 14 Ω·cm, water resistance is grade I.

[0023] Example 4: This embodiment provides a method for preparing the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described above, including the following steps: Step 1: Weigh the raw materials according to the following weight ratio: 10 wt% quartz sand, 4 wt% alumina, 6 wt% sodium carbonate, 2 wt% zirconium oxide, 20 wt% boric acid, 19 wt% zinc oxide, and 60 wt% bismuth oxide. Place them in a V-type mixer and mix for 40 minutes until the mixture is homogeneous, forming a mixture. Step 2: Add the mixture to the quartz crucible of the crucible furnace and keep it at 1150 ℃ for 5 hours to obtain glass melt; Step 3: Quickly pour the molten glass into deionized water for water quenching to obtain glass slag. Put the glass slag and an equal mass of agate balls with a particle size of 15 mm into an agate jar and grind them in a ball mill at 280 revolutions per minute for 40 minutes to obtain coarse glass powder with a D50 particle size of 20-30 micrometers. By weight, 1 part coarse glass powder, 3 parts 5 mm agate pebbles, loose powder and deionized water were placed in an agate jar and ground in a ball mill at 500 rpm for 60 minutes to obtain glass powder with a D50 particle size of 1.0-2.0 micrometers. The spherical-milled wet glass powder was dried at 120℃ for 8 hours and finally passed through a 180-mesh sieve to obtain the finished product. Step 4: Weigh 23g of terpineol, pour it into a beaker, and place it on a heated magnetic stirrer. Weigh 0.75g of ethyl cellulose M70 and add it to the magnetically stirred terpineol in small amounts several times. Initially, it will be a turbid solution. As the stirring continues, the solution will gradually become clear. Continue heating to 100°C. After it becomes uniform, let it stand and cool. Then add 0.8g of Span-85 and continue stirring. After it is uniformly stirred, an organic carrier for electronic paste is prepared. Then seal and store it. Weigh 17 g of the glass powder prepared above and add it to a mortar. Pour in 9 g of the sealed organic carrier and stir until it becomes a paste. Then pour it into a three-roll mill for stirring and dispersion. Pour the slurry into the three-roll mill, roll it three times with the coarse roller until the large particles are dispersed, then roll it three times with the fine roller until the slurry becomes completely paste-like and can flow slowly. This indicates that it is mixed evenly. Seal and store the evenly mixed slurry until it is ready for use. Using screen printing, an encapsulating glass paste was coated onto an alumina substrate with a ruthenium resistive film deposited, resulting in a ruthenium-based thick-film resistor. The encapsulating glass paste was sintered in air at 600°C for 30 minutes and then cooled to obtain Bi₂O₃-B₂O₃-ZnO-SiO₂ electronic packaging glass. The coefficient of thermal expansion of the encapsulated microcrystalline glass was 8.45 × 10⁻⁶. -6 / ℃, insulation resistivity greater than 10 14 Ω·cm, water resistance is grade I.

[0024] Prepare wettability samples and thermal expansion samples for performance testing.

[0025] Methods for preparing wettable samples include (1) Using PVB as a binder, accurately weigh 100 g of the prepared glass powder and place it in a beaker. Use a solution containing 6 wt% PVB (alcohol as a solvent) to prepare the glass powder into a paste. Then slowly add 50 g of the solution to the beaker and stir until uniform. (2) Place the well-stirred sample into a 60 ℃ oven to dry until the alcohol in the sample has completely evaporated; (3) Grind the sample after the alcohol has completely evaporated through a 100-mesh sieve to obtain granules. Then dry the granules in an oven for a period of time and take out the sample. (4) Weigh 3 g of granulated powder and put it into a metal mold with a diameter of 3 mm. Apply a force of 10 KN on the NYL-500 pressure testing machine and hold the pressure for 1 min before demolding to prepare a cylindrical sample with a diameter of 3 mm and a height of 3 mm. (5) The flow and wetting tests of the sample and AlN ceramic were conducted using a CYJ-II-1600 image-based sintering point tester and a button test. First, the prepared cylindrical sample was placed on a 2.5 cm × 2 cm × 2 cm AlN ceramic and placed on the slot of the sintering image tester. The temperature was increased at a rate of 5 ℃ / min, and held at 660℃ for 300 seconds. The wetting angle was calculated by measuring the spreading height h and spreading length x of the sample on the AlN ceramic and using the formula.

[0026] h is the distance from the solid / liquid interface to the top of the hemisphere (mm); x is the spreading diameter of the liquid phase on the solid phase (mm).

[0027] Methods for preparing thermally expanded samples include: (1) Weigh 7 g of sample and pour it into a metal mold. Apply a force of 10 KN using a hydraulic press and hold the pressure for 1 min before demolding. (2) The test strips are sintered in a muffle furnace to ensure that the powder is fixed into blocks and cut into test strips with a length × width × height of 25 mm × 5 mm × 5 mm. (3) The coefficient of thermal expansion (CTE) of the sample was measured using a DIL402C dilatometer from Netzsch GmbH, Germany, at a heating rate of 5 °C / min, in the range of 30 °C to 700 °C.

[0028] Figure 1The images show high-temperature images of the encapsulated glass on AlN ceramics obtained in Examples 1, 2, 3, 4, and 5. At 420°C, all samples remained in a solid block shape without significant morphological changes. This indicates that the temperature had not yet reached the softening or melting temperature of the glass, so the glass remained solid at this temperature and did not flow or spread. At 500°C, the samples began to show varying degrees of shrinkage, indicating that the glass surface had begun to melt, and the temperature was approaching the softening point of the glass. At this point, the glass began to soften but had not yet fully flowed, thus retaining some solid form but having lost some structural rigidity. In this stage, the spreadability of the liquid on the surface was enhanced, but the contact angle may have decreased due to incomplete melting. However, due to the presence of shrinkage, the droplets did not flow completely, and the wettability remained limited. At 575°C, all samples melted into spherical shapes, indicating that the glass had entered the melting stage. At this point, the glass surface completely lost its solid form, had some wettability, and began to form droplets on the ceramic surface. At 660°C, all samples had completely melted and spread, and the glass was in a fully molten state. At this temperature, the wettability of the glass reaches its maximum, allowing the droplets to spread completely and make full contact with the substrate surface. The glass can completely wet the surface and exhibits good flowability and wettability.

[0029] Figure 2 This is a scanning electron microscope (SEM) image of the glass encapsulation layer prepared in Example 3 spread on Al2O3 ceramic; the image on the left shows the distribution of the glass on the ceramic surface. The glass in the image exhibits good fluidity, allowing it to form a relatively uniform spreading structure and coating on the ceramic surface. The glass penetrates deep into the grain gaps of the ceramic, filling these tiny voids and uniformly encapsulating the Al2O3 ceramic grains. This indicates that the glass has good wettability and can fully penetrate into the microstructure of the ceramic, further enhancing the bonding force between the glass and the ceramic.

[0030] Figure 3 The thermal expansion curve of the glass sample obtained in Example 3 is shown. Since glass and Al2O3 ceramic have similar coefficients of thermal expansion, they exhibit similar expansion and contraction behaviors under temperature changes. This compatibility helps reduce thermal stress during thermal cycling, thereby improving the interfacial bonding and encapsulation stability. The good thermal expansion matching between glass and Al2O3 ceramic ensures their effective bonding at high temperatures. This ensures the glass-ceramic encapsulation effect, avoids interfacial cracking or detachment due to thermal stress, and thus improves the overall encapsulation reliability.

[0031] Figure 4The wetting angle variation spectra of the encapsulated glass on AlN ceramics obtained in Examples 1, 2, 3, and 4 are shown. The contact angle of all samples decreased rapidly within the first 50 seconds, indicating that the glass droplets spread rapidly and formed good contact with the Al2O3 ceramic surface during this period. Between 50 and 150 seconds, the change in contact angle began to slow down and stabilized. This indicates that the glass droplets had spread to a certain extent on the ceramic surface, the wettability was significantly improved, and the contact angle began to stabilize. At 150 seconds, the contact angle of all samples was basically stable, meaning that after 150 seconds of holding at the temperature, the glass had fully wetted the ceramic surface and formed a stable encapsulation. The contact angle of all samples eventually approached 20°, indicating that the droplets had spread sufficiently and formed an effective encapsulation.

Claims

1. A Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass, characterized in that, The raw material composition includes: SiO2 6~12wt%, Al2O3 3~5wt%, Na2O 4~7wt%, ZrO2 1~4wt%, B2O3 10~20wt%, ZnO 10~22wt%, Bi2O3 48~60wt%.

2. A method for preparing Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described in claim 1, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the weight ratio and put them into a V-type mixer. Mix for 40-60 minutes until the mixture is uniform and forms a mixture. Step 2: Add the mixture to the quartz crucible of the crucible furnace and keep it at 1030~1150 ℃ for 3~5 h to obtain glass melt; Step 3: Quickly pour the molten glass into deionized water for water quenching to obtain glass slag. After multi-stage ball milling, dry and sieve the glass slag to obtain glass powder. Step 4: Prepare glass powder into a slurry, screen print it onto the surface of the resistor, and sinter it in a muffle furnace at 500~650 ℃ in an air atmosphere, then cool it to obtain Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass.

3. The method for preparing Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described in claim 2, characterized in that, The multi-stage ball milling mentioned in step three is as follows: Glass slag is placed together with an equal mass of agate balls with a particle size of 8-15 mm into an agate jar and ground in a ball mill at 280-320 rpm for 25-40 minutes to obtain coarse glass powder with a D50 particle size of 20-30 micrometers. By weight, 1 part coarse glass powder, 3 parts 2-5 mm agate spheres, and loose deionized water are placed in an agate jar and ground in a ball mill at 400-450 rpm for 60-120 minutes to obtain wet glass powder with a D50 particle size of 1.0-2.0 micrometers.

4. The method for preparing Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described in claim 2, characterized in that, The drying process described in step three involves drying the spheroidized wet glass powder at 120°C for 4-8 hours.

5. The method for preparing Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described in claim 2, characterized in that, The sieving process mentioned in step three involves passing the dried sample through a 150-200 mesh sieve.

6. A Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass prepared by the method according to any one of claims 2 to 5, characterized in that, The coefficient of thermal expansion is 7.8~8.5×10. -6 / ℃.

7. The application of the Bi2O3-B2O3-ZnO-SiO2 electronic packaging glass as described in claim 6 in ruthenium-based thick film resistor packaging.

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