Low dielectric loss low temperature co-fired ceramic material and preparation method thereof

Abstract

This invention discloses a low-dielectric-loss, low-loss, low-temperature co-fired ceramic material and its preparation method, belonging to the field of electronic packaging materials technology. The material comprises a base glass component, a dopant, and additives. The mass percentage of the base glass component is: SiO2 40-47%, B2O3 18-22%, CaO 32-35%, Na2O 0-2%, K2O 0-2%. The dopant is the metal oxide ZnO, with a doping amount of 1-4% of the mass of the base glass. The additive is CaO, with an addition amount of 0.5-2.5% of the mass of the base glass. In the preparation process, the base glass component is first mixed with ZnO, ball-milled, dried, and quenched in melt water. Then, CaO is added, followed by a second ball milling, sieving, granulation, and pressing. Finally, it is sintered at 730-790℃. The resulting material exhibits a dielectric constant ≤6.56 and a dielectric loss ≤0.9×10⁻⁶ at a high frequency of 15GHz. ‑ ³, with a sintering temperature below 800℃, it can be co-fired well with silver and gold electrodes, making it suitable for electronic packaging and high-frequency communication transmission.

Description

Technical Field

[0001] This invention belongs to the field of electronic packaging materials technology, specifically relating to a low-dielectric-low-loss low-temperature co-fired ceramic material and its preparation method. Background Technology

[0002] The rapid development of modern electronic information technology is driving electronic products towards miniaturization, portability, high frequency, and multifunctionality. Electronic packaging materials and technologies play a crucial role in realizing the functionality of electronic devices. Among them, low-temperature co-fired ceramics (LTCC) materials are widely used in electronic packaging materials and high-frequency communication transmission fields due to their advantages such as low sintering temperature, high integration, and stable high-frequency performance. Microcrystalline glass, as an important category of low-temperature co-fired ceramic materials, has received widespread attention from the industry.

[0003] Dielectric properties (mainly including dielectric constant εr and dielectric loss tanδ) are crucial properties of LTCC materials. CaO-B2O3-SiO2 (CBS) glass-ceramics, due to their low dielectric constant and dielectric loss caused by the wollastonite they precipitate, have become a research hotspot in LTCC materials. Variations in the content of CaO, B2O3, and SiO2 in the base glass alter its network structure, thus affecting characteristic temperature points, thermal stability, and crystallization ability; they also influence the type and content of precipitated crystalline phases. Since the structure of the base glass and subsequent crystallization behavior both affect the dielectric properties of the sample, it is necessary to rationally control the composition of the base glass. Furthermore, to promote crystalline phase precipitation, the dielectric properties of CBS glass-ceramics can be further improved by doping with metal oxides or adding different types of substances.

[0004] Currently, several patents relate to improvements in CBS-based LTCC materials. For example, patent CN115572037A dops metal oxides ZrO2 and TiO2 onto CBS-based microcrystalline glass to promote crystallization of the base glass, and adds a CaSiO3-based ceramic phase, preparing a low-temperature co-fired ceramic material after sintering at 800-950℃; its dielectric constant at 10GHz is 5.8-6.3, and its dielectric loss is ≤1.5×10⁻⁶. - ³. Patent CN118324497A uses CBS system microcrystalline glass as a base, adding Al2O3 ceramic phase, metal oxide Nb2O5, K2O and fluoride LiF, etc., to prepare low-temperature co-fired ceramic materials at 800-900℃; however, the dielectric constant was measured to be 6.0-8.5 and the dielectric loss was 0.1-0.6×10 at a low frequency of only 1MHz. -³. Patent CN110372217A first prepares CBS-based microcrystalline glass via melt water quenching, then mixes it with pre-sintered CBS-based ceramic powder, and sintersects it at 800-950℃. The resulting material has a dielectric constant of 6-7.7 and a dielectric loss of <1.7×10⁻⁶ in the 9-13GHz frequency range. - ³.

[0005] Furthermore, patent CN121778998A discloses a low-dielectric-loss, high-strength borosilicate glass-ceramic composite material, composed of 70wt% low borosilicate ratio microcrystalline glass + 29wt% Al2O3 + 1wt% Bi2O3, sintered at 880-900℃, with a dielectric loss of approximately 0.0017-0.0023. Patent CN120058347B uses CBS microcrystalline glass and zinc borosilicate glass as the dual-glass phase, adding Nb2O5, K2O, and CuO, sintered at 800-850℃, achieving a dielectric loss of 0.3×10⁻⁶ at 1MHz. - ³-0.7×10 - ³.

[0006] In summary, existing CBS-based and borosilicate-based low-temperature co-fired ceramic materials still have the following shortcomings:

[0007] 1. The sintering temperature of most existing technologies is above 800℃, or even as high as 950℃, which makes it difficult to achieve good co-firing matching with low melting point and high conductivity electrode materials (such as Ag and Au, with a melting point of about 960℃), and the energy consumption is high.

[0008] 2. Most existing technologies only test dielectric performance at low frequencies (≤13GHz, or even just 1MHz), lacking performance verification at higher frequencies (such as 15GHz and above). As 5G / 6G communication develops towards higher frequencies, low dielectric loss at high frequencies becomes a key indicator.

[0009] 3. While some technologies achieve low dielectric loss at low frequencies, the loss often increases significantly at high frequencies; however, technologies that can be sintered below 800℃ and achieve high-frequency losses of less than 1×10⁻⁶ are more effective. - The material for ³ has not yet been reported.

[0010] 4. Existing technologies often employ the addition of multiple oxides (such as Nb2O5, TiO2, ZrO2, Bi2O3, etc.) or composite glass phases, which increases raw material costs and process control difficulties.

[0011] Therefore, in order to ensure the stability and low energy loss of signal transmission under high frequency conditions (≥15GHz), and at the same time adapt to the temperature matching (<800℃) of conductor electrode materials (gold, silver) during sintering, it is urgent to develop a low-temperature co-fired ceramic material and its simplified preparation method that can be sintered at temperatures below 800℃ and has both low dielectric constant and ultra-low dielectric loss at 15GHz high frequency. Summary of the Invention

[0012] To address the shortcomings of existing technologies, this invention provides a low-dielectric-loss, low-loss, low-temperature co-fired ceramic material and its preparation method. Through a simplified process of ZnO doping followed by the addition of CaO, a dielectric constant ≤6.56 and a dielectric loss ≤0.9×10⁻⁶ are achieved at a low-temperature sintering temperature of 730-790℃ and a high frequency of 15GHz. - The overall performance of ³.

[0013] Therefore, one of the objectives of this invention is to provide a low-dielectric-loss, low-temperature co-fired ceramic material, characterized by comprising a base glass component, a dopant, and an additive; the mass percentage of the base glass component is: SiO2 40-47%, B2O3 18-22%, CaO 32-35%, Na2O 0-2%, K2O 0-2%; the dopant is the metal oxide ZnO, with a doping amount of 1-4% of the mass of the base glass; the additive is CaO, with an addition amount of 0.5-2.5% of the mass of the base glass. Its technical advantages are: by controlling the CBS base glass component and synergistically combining ZnO doping with the subsequent addition of CaO, sintering can be achieved at temperatures below 800℃, and a dielectric constant of 5.0-6.56 and a dielectric loss ≤0.9×10⁻⁶ can be achieved at a high frequency of 15GHz. - The low dielectric and low loss performance of ³ meets the requirements of LTCC co-firing with silver and gold electrodes and high-frequency communication.

[0014] Furthermore, in the basic glass composition, the mass percentage of SiO2 is 43-47%, the mass percentage of B2O3 is 18-21%, and the mass percentage of CaO is 32-35%. The technical effects are: further optimizing the glass network structure, promoting the preferential precipitation of low-dielectric-loss crystalline phases (such as α-SiO2 and β-CaSiO3), and reducing the dielectric constant and dielectric loss of the system.

[0015] Furthermore, the doping amount of the metal oxide ZnO is 2-4%. The technical effect is: appropriately increasing the Zn²⁺ content. + The concentration of this substance can effectively disrupt the [BO4] and [SiO4] groups in the glass network, lower the characteristic temperature of the base glass, promote liquid phase formation, and simultaneously suppress unfavorable crystalline phases, thereby reducing the dielectric loss to 0.64 × 10⁻⁶. - ³ Below.

[0016] Furthermore, the amount of CaO added is 1.0-2.5%. The technical effect is: to introduce Ca²⁺ with a low electric field strength. + Lowering the crystallization activation energy promotes uniform precipitation of wollastonite crystal phase, improves the density of the system, and maintains the dielectric constant stable between 5.58 and 6.56 while lowering the sintering temperature.

[0017] Furthermore, the crystalline phase of the low-temperature co-fired ceramic material is one or more of β-CaSiO3, α-CaSiO3, α-SiO2, and CaB2O4. The technical advantages are: these crystalline phases themselves possess low dielectric constant (4-5) and low dielectric loss (10). -4 By adjusting the type and proportion of crystal phases (on a scale of 1000 kilometres per second), the dielectric stability of the material at high frequencies can be further improved.

[0018] This invention also discloses a method for preparing a low-dielectric-loss, low-loss low-temperature co-fired ceramic material as described in any of the above claims, comprising the following steps: weighing a base glass component and a metal oxide ZnO according to a specified ratio, mixing them, and then ball-milling them; drying the ball-milled slurry to obtain a dry mixed powder; melting the mixed powder at 1300-1400℃, and then water-quenching it to obtain base glass particles; adding CaO to the base glass particles, ball-milling them a second time, and sieving them to obtain a composite powder; adding a binder to the composite powder for granulation and pressing to obtain a green body; and sintering the green body at 730-790℃ to obtain the low-temperature co-fired ceramic material.

[0019] This technical solution adopts a step-by-step process of "first melting the base glass and then adding CaO", which avoids excessive network modification of CaO in the high-temperature melting stage, facilitates independent control of glass formation and crystallization behavior, and combines it with one-step sintering at a low temperature of 730-790℃ to simplify the process and ensure compatibility with electrode materials.

[0020] Furthermore, the melting time is 1-3 hours, which can ensure that the raw materials are fully melted to form a homogeneous glass melt, avoiding residual crystalline phases or component segregation due to incomplete melting, thereby ensuring the uniformity of subsequent crystallization.

[0021] Furthermore, the sieve mesh size is 100-200 mesh; and / or, the binder is an aqueous solution of polyvinyl alcohol with a volume percentage concentration of 1-5%. This mesh size ensures uniform powder particle size and improves the consistency of green body density; the 5% PVA binder provides moderate plasticity, ensuring sufficient strength of the green body after compression molding and leaving no residue after glue removal.

[0022] Furthermore, the sintering time is 0.25-1 hour. Short-time sintering can suppress excessive grain growth, maintain a fine-grained structure, and reduce dielectric loss; at the same time, it ensures that densification is completed and high flexural strength is obtained.

[0023] Furthermore, the low-dielectric-loss, low-temperature co-fired ceramic material has applications in electronic packaging and high-frequency communication transmission. Utilizing its low dielectric constant, ultra-low dielectric loss, and low-temperature co-firing characteristics, this material can be used to manufacture microwave devices such as high-frequency filters, resonators, and antenna substrates, thereby improving signal transmission speed and integrity.

[0024] The advantages and positive effects of this invention are: The low-temperature co-fired ceramic material of this invention possesses excellent dielectric properties and a low sintering temperature, making CBS-system glass-ceramics widely used as low-temperature co-fired ceramic materials. Different crystalline phases precipitated in CBS-system glass-ceramics exhibit different dielectric properties, such as the dielectric constant (ε) of wollastonite (α, β-CaSiO3). r ) is 5, dielectric loss (tanδ) = 1 - 3 × 10 -4 α-SiO2 dielectric constant (ε r The dielectric loss (tanδ) is 4, and the dielectric loss (tanδ) is 1.0 × 10⁻⁶. -4 The dielectric constant of CaB₂O₄ (ε) r The value is 4.

[0025] This invention limits the content of the basic glass components of CBS system microcrystalline glass, and regulates the content of the glass network modifier CaO, the glass network forming body SiO2, and B2O3 which has both network repair and network breaking capabilities, so that the precipitated crystal phase is one or more of β-CaSiO3, α-CaSiO3, α-SiO2 and CaB2O4 with low dielectric and low loss.

[0026] Metal oxide doping affects the crystallization behavior and dielectric properties of the CBS system base glass. This can be achieved by doping with the metal oxide ZnO and utilizing the Zn introduced by the doping. 2+ A larger ionic radius disrupts weaker chemical bonds in the original glass system, making the network structure more compact, reducing dielectric loss caused by structural defects, and adjusting the polarization direction of the system. Simultaneously, it enhances the system's insulation capacity, reduces electron movement within the system, and decreases dielectric loss caused by electron conduction. On the other hand, the doped metal oxide ZnO also acts as a nucleating agent, promoting the growth of crystalline phases in the base glass. When the number of crystalline phases is large and uniform, the glass phase content decreases, the number of grain boundaries increases, and the space charge polarization at the grain boundaries is weaker, which is beneficial for reducing the system's dielectric loss.

[0027] After preparing the CBS system base glass, CaO was introduced. The dielectric properties of the CBS system glass-ceramic were affected by the crystallization behavior of the system during sintering, and CaO... 2+ The ionic potential (2.02) is significantly lower than that of other high-valence cations such as P. 5+(13.16), Ti 4+ (6.61), Al 3+ (5.61), and the smaller the ionic potential, the lower the electric field strength. The addition of CaO will introduce more Ca with low electric field strength into the system. 2+ This helps to reduce the activation energy of crystallization in the system and promotes crystallization, thereby improving the dielectric properties of the CBS system glass-ceramic.

[0028] Based on CBS system microcrystalline glass, ZnO metal oxide is used for doping and CaO is added to the base glass to precipitate a low-dielectric-loss crystalline phase at a lower sintering temperature. This ultimately yields a low-temperature co-fired ceramic material exhibiting low dielectric loss at high frequencies (15 GHz). Attached Figure Description

[0029] Figure 1 This is a process flow diagram of the preparation method of the present invention. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below; obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In this invention, the dielectric loss and dielectric constant were determined according to the GB / T5594.4-2015 standard. Five samples were prepared for each component of each test, and LCR instruments were used for testing at a frequency of 15 GHz.

[0032] The specific preparation process is as follows: Step 1: The base glass components and the doped metal oxide ZnO are ball-milled and mixed according to the raw material mass ratio in Table 1. Step 2: After melting and quenching in water at a temperature of 1300-1400℃, the CBS system base glass is obtained, and after drying, CaO is added. The glass is then ball-milled a second time to obtain composite powder. Step 3: The composite powder is sieved and granulated using a binder to prepare a disc-shaped green body; Step 4: Low-temperature co-fired ceramic materials are prepared using a one-step sintering method.

[0033] In step 1, the first ball milling is wet milling, with a milling speed of 150 r / min and a time of 60 min; in step 2, the second ball milling is dry milling, with a milling speed of 250 r / min and a time of 60 min, and ball milling can be performed multiple times; in step 3, the base glass powder is sieved through a 200-mesh sieve, and the binder is PVA (5% volume percentage of polyvinyl alcohol aqueous solution); the diameter of the round green body is 20 mm and the thickness is 1.5 mm; in step 4, the sintering temperature of the one-step sintering method is 730-790℃, and the sintering time is 0.25-1 h.

[0034] Table 1. Raw material mass ratio (wt%) and process parameters for each embodiment.

[0035] Example 1 Step 1: Weigh each raw material according to the proportions in Example 1 in Table 1 using an electronic balance; weigh 46wt% SiO2, 35wt% CaO, 18wt% B2O3, 1wt% Na2O, and 4wt% ZnO and place them in a polytetrafluoroethylene ball mill jar. Use deionized water as the ball milling medium and zirconia balls as grinding balls. Mix the materials, deionized water, and grinding balls at a mass ratio of 1:1:1.5 and place them in a planetary ball mill. Ball mill (wet mill) at a speed of 150 r / min for 1 hour to obtain a mixed slurry. Step 2: Pour the ball-milled slurry into a drying tray and place it in a drying oven at 70°C for 12 hours to obtain dried powder; Step 3: Place the dried powder into an alumina crucible, place the alumina crucible in a high-temperature muffle furnace and heat it to 1350°C at a heating rate of 5°C / min, and melt it for 2 hours; then, quickly pour the melt into deionized water for water quenching to obtain basic glass particles. Step 4: Place the base glass particles in a drying oven and dry them at 70°C for 12 hours. Then, add 0.5wt% CaO to the dried base glass particles and place them in a polytetrafluoroethylene ball mill jar. Perform secondary ball milling (dry milling) in a planetary ball mill at a material-to-ball ratio of 1:1 to make the composite powder pass through a 100-mesh sieve. Step 5: Mix the sieved composite powder with PVA (5% volume percentage of polyvinyl alcohol aqueous solution) at a mass ratio of 7:1 and granulate. Then press and shape it into round green discs with a diameter of 20 mm and a thickness of 1.5 mm.

[0036] Step 6: Place the round green blank in a muffle furnace and heat it to 730°C at a heating rate of 5°C / min. Sinter for 0.5 hours and then cool it to room temperature with the furnace to obtain a low-temperature co-fired ceramic material, i.e., microcrystalline glass.

[0037] Results: The obtained glass-ceramic had crystalline phases of β-CaSiO3, α-CaSiO3, and CaB2O4. According to GB / T5594.4-2015 standard, LCR instrument was used for testing at a frequency of 15 GHz. The dielectric loss was 0.00075, and the dielectric constant was 6.25.

[0038] Example 2 Step 1: Weigh each raw material according to the proportions in Example 2 in Table 1 using an electronic balance; weigh 46wt% SiO2, 35wt% CaO, 18wt% B2O3, 1wt% K2O, 1wt% Na2O, and 4wt% ZnO and put them into a polytetrafluoroethylene ball mill jar. Use deionized water as the ball milling medium and zirconia balls as grinding balls. Mix the materials, deionized water, and grinding balls at a mass ratio of 1:1:1.5 and place them in a planetary ball mill. Ball mill (wet mill) at a speed of 150 r / min for 1 hour to obtain a mixed slurry. Step 2: Pour the ball-milled slurry into a drying tray and place it in a drying oven at 70°C for 12 hours to obtain dried powder; Step 3: Place the dried powder into an alumina crucible, place the alumina crucible in a high-temperature muffle furnace and heat it to 1300°C at a heating rate of 5°C / min, and melt it for 2 hours; then, quickly pour the melt into deionized water for water quenching to obtain basic glass particles. Step 4: Place the base glass particles in a drying oven and dry them at 70°C for 12 hours. Then, add 1 wt% CaO to the dried base glass particles and place them in a polytetrafluoroethylene ball mill jar. Perform secondary ball milling (dry milling) in a planetary ball mill at a material-to-ball ratio of 1:1 to make the composite powder pass through a 150-mesh sieve. Step 5: Mix the sieved composite powder with PVA (5% volume percentage of polyvinyl alcohol aqueous solution) at a mass ratio of 7:1 and granulate. Then press and shape it into round green discs with a diameter of 20 mm and a thickness of 1.5 mm.

[0039] Step 6: Place the circular green blank in a muffle furnace and heat it to 770°C at a heating rate of 5°C / min. Sinter for 0.25 hours, and then cool it to room temperature with the furnace to obtain a low-temperature co-fired ceramic material, i.e., microcrystalline glass.

[0040] Results: The obtained glass-ceramic had crystalline phases of β-CaSiO3, α-CaSiO3, and CaB2O4. According to GB / T5594.4-2015 standard, LCR instrument was used for testing at a frequency of 15 GHz. The dielectric loss was 0.00064, and the dielectric constant was 5.58.

[0041] Example 3 Step 1: Weigh each raw material according to the proportions in Example 3 in Table 1 using an electronic balance; weigh 45wt% SiO2, 33wt% CaO, 20wt% B2O3, 1wt% K2O, 1wt% Na2O, and 3wt% ZnO and place them in a polytetrafluoroethylene ball mill jar. Use deionized water as the ball milling medium and zirconia balls as grinding balls. Mix the materials, deionized water, and grinding balls at a mass ratio of 1:1:1.5 and place them in a planetary ball mill at a speed of 150 r / min (wet milling) for 1 hour to obtain a mixed slurry. Step 2: Pour the ball-milled slurry into a drying tray and place it in a drying oven at 70°C for 12 hours to obtain dried powder; Step 3: Place the dried powder into an alumina crucible, place the alumina crucible in a high-temperature muffle furnace and heat it to 1400°C at a heating rate of 5°C / min, and melt it for 2 hours; then, quickly pour the melt into deionized water for water quenching to obtain basic glass particles. Step 4: Place the base glass particles in a drying oven and dry them at 70°C for 12 hours. Then, add 1.5wt% CaO to the dried base glass particles and place them in a polytetrafluoroethylene ball mill jar. Perform secondary ball milling (dry milling) in a planetary ball mill at a material-to-ball ratio of 1:1 to make the composite powder pass through a 200-mesh sieve. Step 5: Mix the sieved composite powder with PVA (5% volume percentage of polyvinyl alcohol aqueous solution) at a mass ratio of 7:1 and granulate. Then press and shape it into round green discs with a diameter of 20 mm and a thickness of 1.5 mm.

[0042] Step 6: Place the circular green blank in a muffle furnace and heat it to 750°C at a heating rate of 5°C / min. Sinter for 0.75 hours, and then cool it to room temperature with the furnace to obtain a low-temperature co-fired ceramic material, namely microcrystalline glass.

[0043] Results: The obtained glass-ceramic had crystalline phases of β-CaSiO3, α-CaSiO3, and α-SiO2. According to GB / T5594.4-2015 standard, LCR instrument was used for testing at a frequency of 15 GHz. The dielectric loss was 0.00056, and the dielectric constant was 5.0.

[0044] Example 4 Step 1: Weigh each raw material according to the proportions in Example 4 in Table 1 using an electronic balance; weigh 43wt% SiO2, 34wt% CaO, 21wt% B2O3, 2wt% K2O, and 2wt% ZnO and place them in a polytetrafluoroethylene ball mill jar. Use deionized water as the ball milling medium and zirconia balls as grinding balls. Mix the materials, deionized water, and grinding balls at a mass ratio of 1:1:1.5 and place them in a planetary ball mill at a speed of 150 r / min (wet milling) for 1 hour to obtain a mixed slurry. Step 2: Pour the ball-milled slurry into a drying tray and place it in a drying oven at 70°C for 12 hours to obtain dried powder; Step 3: Place the dried powder into an alumina crucible, place the alumina crucible in a high-temperature muffle furnace and heat it to 1350°C at a heating rate of 5°C / min, and melt it for 2 hours; then, quickly pour the melt into deionized water for water quenching to obtain basic glass particles. Step 4: Place the base glass particles in a drying oven and dry them at 70°C for 12 hours. Then, add 2wt% CaO to the dried base glass particles and place them in a polytetrafluoroethylene ball mill jar. Perform secondary ball milling (dry milling) in a planetary ball mill at a material-to-ball ratio of 1:1 to make the composite powder pass through a 200-mesh sieve. Step 5: Mix the sieved composite powder with PVA (5% volume percentage of polyvinyl alcohol aqueous solution) at a mass ratio of 7:1 and granulate. Then press and shape it into round green discs with a diameter of 20 mm and a thickness of 1.5 mm.

[0045] Step 6: Place the round green blank in a muffle furnace and heat it to 770°C at a heating rate of 5°C / min. Sinter for 0.5 hours and then cool it to room temperature with the furnace to obtain the low-temperature co-fired ceramic material, i.e., microcrystalline glass.

[0046] Results: The obtained glass-ceramic had crystalline phases of β-CaSiO3, α-SiO2, and CaB2O4. According to GB / T5594.4-2015 standard, LCR instrument was used for testing at a frequency of 15 GHz. The dielectric loss was 0.00070, and the dielectric constant was 6.12.

[0047] Example 5 Step 1: Weigh each raw material according to the proportions in Example 5 in Table 1 using an electronic balance; weigh 40wt% SiO2, 34wt% CaO, 22wt% B2O3, 2wt% K2O, 2wt% Na2O, and 1wt% ZnO and place them in a polytetrafluoroethylene ball mill jar. Use deionized water as the ball milling medium and zirconia balls as grinding balls. Mix the materials, deionized water, and grinding balls at a mass ratio of 1:1:1.5 and place them in a planetary ball mill. Ball mill (wet mill) at a speed of 150 r / min for 1 hour to obtain a mixed slurry. Step 2: Pour the ball-milled slurry into a drying tray and place it in a drying oven at 70°C for 12 hours to obtain dried powder; Step 3: Place the dried powder into an alumina crucible, place the alumina crucible in a high-temperature muffle furnace and heat it to 1400°C at a heating rate of 5°C / min, and melt it for 2 hours; then, quickly pour the melt into deionized water for water quenching to obtain basic glass particles. Step 4: Place the base glass particles in a drying oven and dry them at 70°C for 12 hours. Then, add 2.5wt% CaO to the dried base glass particles and place them in a polytetrafluoroethylene ball mill jar. Perform secondary ball milling (dry milling) in a planetary ball mill at a material-to-ball ratio of 1:1 to make the composite powder pass through a 200-mesh sieve. Step 5: Mix the sieved composite powder with PVA (5% volume percentage of polyvinyl alcohol aqueous solution) at a mass ratio of 7:1 and granulate. Then press and shape it into round green discs with a diameter of 20 mm and a thickness of 1.5 mm.

[0048] Step 6: Place the round green blank in a muffle furnace and heat it to 790°C at a heating rate of 5°C / min. Sinter for 1 hour, and then cool it to room temperature with the furnace to obtain a low-temperature co-fired ceramic material, i.e., microcrystalline glass.

[0049] Results: The obtained glass-ceramic has β-CaSiO3 and α-CaSiO3 as its crystalline phases. According to GB / T5594.4-2015 standard, LCR instrument was used for testing at a frequency of 15 GHz. The dielectric loss was 0.00085, and the dielectric constant was 6.43.

[0050] Example 6 Step 1: Weigh each raw material according to the proportions in Example 6 in Table 1 using an electronic balance; weigh 45wt% SiO2, 33wt% CaO, 20wt% B2O3, 1wt% K2O, 1wt% Na2O, and 3wt% ZnO and place them in a polytetrafluoroethylene ball mill jar. Use deionized water as the ball milling medium and zirconia balls as grinding balls. Mix the materials, deionized water, and grinding balls at a mass ratio of 1:1:1.5 and place them in a planetary ball mill. Ball mill (wet mill) at a speed of 150 r / min for 1 hour to obtain a mixed slurry. Step 2: Pour the ball-milled slurry into a drying tray and place it in a drying oven at 70°C for 12 hours to obtain dried powder; Step 3: Place the dried powder into an alumina crucible, place the alumina crucible in a high-temperature muffle furnace and heat it to 1400°C at a heating rate of 5°C / min, and melt it for 2 hours; then, quickly pour the melt into deionized water for water quenching to obtain basic glass particles. Step 4: Place the basic glass particles in a drying oven and dry them at 70°C for 12 hours. Then, place them in a polytetrafluoroethylene ball mill jar and perform secondary ball milling (dry milling) in a planetary ball mill at a material-to-ball ratio of 1:1 to make the basic glass powder pass through a 200-mesh sieve. Step 5: Mix the sieved base glass powder with PVA (5% volume percentage of polyvinyl alcohol aqueous solution) at a mass ratio of 7:1 and granulate. Then press it into a round green plate with a diameter of 20mm and a thickness of 1.5mm.

[0051] Step 6: Place the circular green blank in a muffle furnace and heat it to 750°C at a heating rate of 5°C / min. Sinter for 0.75 hours, and then cool it to room temperature with the furnace to obtain a low-temperature co-fired ceramic material, namely microcrystalline glass.

[0052] Results: The obtained glass-ceramic glass has β-CaSiO3 and α-SiO2 crystalline phases. According to GB / T5594.4-2015 standard, LCR instrument was used for testing at a frequency of 15 GHz. The dielectric loss was 0.00087, and the dielectric constant was 6.56.

[0053] Data Analysis: As can be seen from the results in Table 1, the sintering temperatures of the low-temperature co-fired ceramic materials prepared in each embodiment of the present invention are all in the range of 730-790℃, which is much lower than the above 800℃ in the prior art, and meets the requirements for co-firing with electrode materials such as silver and gold.

[0054] Regarding dielectric properties, all embodiments achieved a low dielectric constant of 5.0-6.56 and an ultra-low dielectric loss of 0.56 × 10⁻⁶ at a high frequency of 15 GHz. - ³-0.87×10 - ³, thus fully achieving the technical effects claimed in this invention.

[0055] A comparison of different embodiments reveals that: Example 3 (45% SiO2, 20% B2O3, 33% CaO, 3% ZnO doping, 1.5% CaO addition, sintered at 750℃) obtained the lowest dielectric constant (5.0) and the lowest dielectric loss (0.00056). α-SiO2 appeared in its crystalline phase, which is consistent with the mechanism analysis in this invention regarding the benefits of ZnO doping for the precipitation of low dielectric and low loss α-SiO2 crystalline phase.

[0056] Example 2 (4% ZnO doping, 1.0% CaO addition, sintering at 770°C) yielded the second lowest dielectric loss (0.00064).

[0057] Example 6 (3% ZnO doping, no CaO added, sintered at 750℃) achieved the highest dielectric constant (6.56) and relatively high dielectric loss (0.00087), but its performance is still far superior to the prior art.

[0058] In summary, this invention, through precise control of the base glass composition, doping with ZnO metal oxide, and adding a specific amount of CaO after the base glass is prepared, combined with an optimized one-step sintering process, successfully prepared a low-temperature co-fired ceramic material with excellent low dielectric and low loss performance under high-frequency (15GHz) conditions at a sintering temperature below 800℃. It has good prospects for industrial application and can be applied to electronic packaging and high-frequency communication transmission fields.

[0059] The embodiments given above are preferred examples for implementing the present invention, and the present invention is not limited to the above embodiments. Any non-essential additions or substitutions made by those skilled in the art based on the technical features of the present invention are within the protection scope of the present invention.

Claims

1. A low-dielectric-loss, low-loss, low-temperature co-fired ceramic material, characterized in that, It includes a base glass component, dopants, and additives; the mass percentage of the base glass component is: SiO2 40-47%, B2O3 18-22%, CaO 32-35%, Na2O 0-2%, K2O 0-2%; the dopant is the metal oxide ZnO, and the doping amount is 1-4% of the mass of the base glass; the additive is CaO, and the addition amount is 0.5-2.5% of the mass of the base glass.

2. The low-dielectric-loss, low-loss low-temperature co-fired ceramic material according to claim 1, characterized in that, In the basic glass composition, the mass percentage of SiO2 is 43-47%, the mass percentage of B2O3 is 18-21%, and the mass percentage of CaO is 32-35%.

3. The low-dielectric-loss, low-loss low-temperature co-fired ceramic material according to claim 1, characterized in that, The doping amount of the metal oxide ZnO is 2-4%.

4. The low-dielectric-loss, low-loss low-temperature co-fired ceramic material according to claim 1, characterized in that, The amount of CaO added is 1.0-2.5%.

5. The low-dielectric-loss, low-loss low-temperature co-fired ceramic material according to claim 1, characterized in that, The crystalline phase of the low-temperature co-fired ceramic material is one or more of β-CaSiO3, α-CaSiO3, α-SiO2, and CaB2O4.

6. A method for preparing a low-dielectric-loss, low-loss low-temperature co-fired ceramic material as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Weigh the basic glass components and metal oxide ZnO according to the ratio, mix them and then ball mill them; S2: Dry the ball-milled slurry to obtain a dry mixed powder; S3: Melt the mixed powder at 1300-1400℃, then quench it with water to obtain basic glass particles; S4: Add CaO to the basic glass particles, perform secondary ball milling and sieving to obtain composite powder; S5: Add a binder to the composite powder, granulate, and press to form a green body; S6: The green body is sintered at 730-790℃ to obtain a low-temperature co-fired ceramic material.

7. The preparation method according to claim 6, characterized in that, The melting time in step S3 is 1-3 hours.

8. The preparation method according to claim 6, characterized in that, The sieve used in step S4 has a mesh size of 100-200; and / or the binder is an aqueous solution of polyvinyl alcohol with a volume percentage concentration of 1-5%.

9. The preparation method according to claim 6, characterized in that, The sintering time in step S6 is 0.25-1 hour.

10. The application of the low-dielectric-low-loss low-temperature co-fired ceramic material according to any one of claims 1-5 in the fields of electronic packaging or high-frequency communication transmission.

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