Silicate-based microwave dielectric ceramic material, ltcc material and preparation method

Abstract

The application belongs to the technical field of microwave dielectric ceramic materials and LTCC materials, and more particularly relates to a silicate-based microwave dielectric ceramic material, an LTCC material and a preparation method. A ZrSi2O7, wherein A Ca, Sr, Ba, a solid solution Ca 1‑x Sr x , a solid solution Ca 1‑x Ba x or a solid solution Sr 1‑x Ba x , 0.2<=x<=0.8, has low dielectric constant, high quality factor and excellent dielectric performance. The application realizes sintering at 850 DEG C to 900 DEG C by optimizing the material components, and obtains an LTCC material with medium-low dielectric constant, high quality factor and good resonant frequency temperature coefficient, which has the advantages of simple preparation process, stable performance and the like, and is suitable for preparing LTCC low-pass filters, LTCC band-pass filters, multilayer ceramic substrates and the like special ceramic passive microwave devices.

Description

Technical Field

[0001] This application belongs to the technical field of microwave dielectric ceramic materials and LTCC materials, and more specifically, relates to a silicate-based microwave dielectric ceramic material, an LTCC material, and a preparation method thereof. Background Technology

[0002] Microwave dielectric ceramics are fundamental materials for fabricating communication devices such as microwave substrates, dielectric filters, and dielectric antennas, and are widely used in various wireless communication systems including communication base stations, satellites, and mobile phones. The rapid development of 5G technology is driving the miniaturization, integration, and multi-functionality of electronic components. As the integration level and operating frequency of communication equipment continue to increase, problems such as signal delay, crosstalk, system heat generation, and operational stability are becoming increasingly prominent. Microwave dielectric ceramics with medium to low dielectric constants and high quality factors can effectively improve the transmission rate of microwave signals and reduce signal energy loss and system heat generation; therefore, research on microwave dielectric ceramics with medium to low dielectric constants is particularly important.

[0003] Low-temperature co-fired ceramics (LTCC) technology is a novel multilayer substrate process technology. By encapsulating electrode materials, ceramic substrates, and electronic components into one unit, it creates multilayer or three-dimensional circuit substrates. This enables high-density wiring and the integration of various passive devices, promoting the miniaturization, integration, high-frequency operation, multifunctionality, and high reliability of electronic products.

[0004] Low-temperature co-fired ceramic (LTCC) materials, as the core materials of low-temperature co-fired ceramic technology, have low sintering temperatures (below 950℃) and can be co-fired with metallic conductors such as Ag, Cu, and Au, significantly improving the performance of electronic devices. Among these, LTCC materials with medium to low dielectric constants are crucial for fabricating LTCC low-pass and band-pass filters. However, the fabrication processes of commonly used LTCC materials are complex, requiring large-scale glass melting, and LTCC materials exhibit poor electroplating characteristics and performance stability. Patent document CN115353383A discloses a low-temperature co-fired ceramic material (Zn... 0.9 Cu 0.1 ) 0.15 Nb 0.3 (Ti 0.9 Zr 0.1 ) 0.55 O2 can be sintered to a dense state at 850℃~900℃, but its dielectric constant is 52.7. An excessively high dielectric constant is not conducive to reducing transmission delay under millimeter waves and cannot be used as a high-frequency substrate material.

[0005] Developing novel microwave dielectric ceramic materials and LTCC materials with low to medium dielectric constants and high quality factors is of great significance for promoting the development of electronic components. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application aims to provide a silicate-based microwave dielectric ceramic material, a low-temperature co-fired (LTCC) material, and a preparation method thereof. This broadens the selection range of microwave dielectric ceramic materials with medium to low dielectric constants, which is beneficial for optimizing signal delay and system heat generation issues in microwave communicators. Furthermore, by optimizing the material composition, sintering at 850℃~900℃ is achieved to obtain a low-temperature co-fired ceramic material (LTCC material) that combines medium to low dielectric constants, high quality factor, and a good temperature coefficient of resonant frequency. This contributes to promoting the miniaturization, integration, and high reliability of devices.

[0007] To achieve the above objectives, in a first aspect, this application provides a silicate-based microwave dielectric ceramic material, the compositional formula of which is as follows: A ZrSi2O7, in which A For Ca, Sr, Ba, and solid solution Ca 1-x Sr x solid solution Ca 1-x Ba x or solid solution Sr 1-x Ba x , 0.2≤x≤0.8.

[0008] Preferably, the dielectric constant ε of the above-mentioned silicate-based microwave dielectric ceramic material is... r The quality factor is 9-11. Q × f The resonant frequency temperature coefficient ranges from 24,000 GHz to 68,000 GHz. τ f The value is -35ppm / ℃ to -20ppm / ℃.

[0009] Secondly, this application provides a method for preparing the above-mentioned silicate-based microwave dielectric ceramic material, characterized by comprising the following steps:

[0010] (1) According to the above composition expression A The raw materials of ZrSi2O7 were prepared according to the stoichiometric ratio, ball-milled, dried, and then pre-calcined to obtain pre-calcined powder.

[0011] (2) The above-mentioned pre-fired powder is ball-milled again, dried and mixed with binder to granulate and pressed into a ceramic green body, and then sintered to obtain the above-mentioned silicate-based microwave dielectric ceramic material.

[0012] Preferably, in step (1), the pre-firing temperature is 1200℃~1300℃ and the pre-firing time is 4h~6h.

[0013] Preferably, in step (2), the sintering temperature is 1400℃~1450℃ and the sintering time is 8h~12h.

[0014] Thirdly, this application provides an LTCC material comprising a main crystalline phase and a sintering aid; wherein the compositional formula of the main crystalline phase is as follows: A ZrSi2O7, in which A For Ca, Sr, Ba, and solid solution Ca 1-x Sr x solid solution Ca 1-x Ba x or solid solution Sr 1-x Ba x , 0.2≤x≤0.8;

[0015] The above-mentioned sintering aid includes a mixture of 0.33CuO and 0.67H3BO3.

[0016] Preferably, the above-mentioned sintering aid also includes one or more of TiO2 and CaTiO3.

[0017] Preferably, the amount of the above-mentioned 0.33CuO-0.67H3BO3 mixture added is 5wt%~10wt%.

[0018] Preferably, the amount of TiO2 added is 0wt%~10wt%.

[0019] Preferably, the amount of CaTiO3 added is 0wt%~10wt%.

[0020] Fourthly, this application provides a method for preparing the above-mentioned LTCC material, comprising the following steps:

[0021] S1. According to the above composition expression A The raw materials of ZrSi2O7 were prepared according to the stoichiometric ratio, ball-milled, dried, and then pre-calcined to obtain pre-calcined powder.

[0022] S2. The above-mentioned pre-fired powder and the above-mentioned sintering aid are mixed, ball-milled again, dried, mixed with binder, granulated and pressed into shape to obtain a low-temperature co-fired ceramic green body, and then sintered to obtain the above-mentioned LTCC material.

[0023] Preferably, in step S1, the pre-firing temperature is 1200℃~1300℃, and the pre-firing time is 4h~6h.

[0024] Preferably, in step S2, the sintering temperature is 850℃~900℃ and the sintering time is 3h~5h.

[0025] Fifthly, this application provides the application of the above-mentioned LTCC material in the fabrication of LTCC low-pass filters, LTCC band-pass filters, and multilayer ceramic substrates.

[0026] In summary, the technical solutions conceived in this application have the following main technical advantages compared with the prior art:

[0027] (1) The silicate-based microwave dielectric ceramic material provided in this application has the following chemical formula: A ZrSi2O7, in which A It consists of Ca, Sr, Ba and their solid solutions, and possesses excellent dielectric properties, with a dielectric constant ε. r The quality factor is 9-11. Q × f The resonant frequency temperature coefficient ranges from 24,000 GHz to 68,000 GHz. τ f With a dielectric constant of -35ppm / ℃ to -20ppm / ℃, the low dielectric constant can improve the transmission rate of microwave signals in the medium and alleviate signal delay problems. The high quality factor makes it suitable for manufacturing various special ceramic products, such as dielectric waveguide filters, dielectric resonators and dielectric antennas, and other high-frequency microwave communication devices.

[0028] (2) The LTCC material provided in this application can be sintered at a lower sintering temperature (850℃~900℃), which is suitable for the temperature requirements of co-firing with Ag, Cu and other electrodes, meets the requirements of LTCC process, and has the advantages of simple preparation process and stable performance of LTCC material.

[0029] (3) By adjusting the ratio of pre-burned powder and sintering aid, this application can prepare LTCC materials with both low and medium dielectric constants, good quality factors, and good temperature coefficients of resonant frequencies. r Adjustable from 8.5 to 16 Q × f Adjustable from 10000GHz to 35000GHz τ f Adjustable from -40ppm / ℃ to +10ppm / ℃, it is suitable for fabricating special ceramic passive microwave devices with complex structures such as LTCC low-pass filters, LTCC band-pass filters, multilayer ceramic substrates, sensors, and microelectromechanical systems (MEMS). Attached Figure Description

[0030] Figure 1 This is a schematic flowchart of the preparation method of silicate-based microwave dielectric ceramic material and LTCC material provided in the embodiments of this application;

[0031] Figure 2These are XRD patterns of the silicate-based microwave dielectric ceramic material and LTCC material prepared in the embodiments of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] In the description of this application, it should be understood that the term "and / or" describes a relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The symbol " / " in this document indicates that the related objects are in an "or" relationship; for example, A / B means A or B.

[0034] In the description of the embodiments in this application, the words "exemplary" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0035] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more.

[0036] This application provides a silicate-based microwave dielectric ceramic material, the compositional formula of which is as follows: A ZrSi2O7, in which A For Ca, Sr, Ba, and solid solution Ca 1-x Sr x solid solution Ca 1-x Ba x or solid solution Sr 1- x Ba x , 0.2≤x≤0.8.

[0037] pass A The synergistic effect of the components in ZrSi2O7 microwave dielectric ceramic materials gives silicate-based microwave dielectric ceramic materials excellent dielectric properties, with a dielectric constant ε. r The quality factor is 9-11. Q × f The resonant frequency temperature coefficient ranges from 24,000 GHz to 68,000 GHz. τ fWith a dielectric constant of -35ppm / ℃ to -20ppm / ℃, the low dielectric constant can improve the transmission rate of microwave signals in the medium and alleviate signal delay problems. The high quality factor makes it suitable for manufacturing various special ceramic products, such as dielectric waveguide filters, dielectric resonators and dielectric antennas, and other high-frequency microwave communication devices.

[0038] On the other hand, such as Figure 1 As shown, this application also provides a method for preparing the above-mentioned silicate-based microwave dielectric ceramic material, comprising the following steps:

[0039] (1) According to the above composition expression A The raw materials of ZrSi2O7 were prepared according to the stoichiometric ratio, ball-milled, dried, and then pre-calcined to obtain pre-calcined powder.

[0040] (2) The above-mentioned pre-fired powder is ball-milled again, dried and mixed with binder to granulate and pressed into a ceramic green body, and then sintered to obtain the above-mentioned silicate-based microwave dielectric ceramic material.

[0041] In some embodiments, in step (1), the raw materials are oxides or carbonates of metal elements, etc. Furthermore, the purity of the raw materials is greater than or equal to 99.5%, which effectively reduces the introduction of impurities and avoids the impact of impurities on the purity and electrochemical performance of silicate-based microwave dielectric ceramic materials. In specific embodiments of this application, the raw material components include CaCO3, SrCO3, BaCO3, ZrO2, and SiO2.

[0042] In some embodiments, in step (1), the ball milling is wet ball milling. The wet ball milling includes the following steps: milling the prepared raw materials, solvent, and milling balls at a mass ratio of 1:(1~2):(3~7) for 10h~15h. The solvent may be, but is not limited to, deionized water. The milling balls may be, but are not limited to, zirconium balls.

[0043] In some embodiments, in step (1), the drying temperature is 70°C to 90°C and the drying time is 12h to 24h.

[0044] In some embodiments, in step (1), the pre-calcination temperature is 1200℃~1300℃ and the pre-calcination time is 4h~6h, so that the mixed powder is fully mixed and forms a pre-calcined powder with uniformly dispersed components.

[0045] In some embodiments, in step (2), the ball milling is a wet ball milling process. The wet ball milling process includes the following steps: milling the pre-calcined powder, solvent, and milling balls at a mass ratio of 1:(1~2):(3~7) for 10h~15h. The solvent may be, but is not limited to, deionized water. The milling balls may be, but are not limited to, zirconium balls.

[0046] In some embodiments, in step (2), the binder includes, but is not limited to, at least one of polyvinyl alcohol (PVA) and polyethylene glycol (PEG), which can improve the bonding performance between the components and facilitate the molding of the powder into device products. In some embodiments, the amount of the binder is 5wt% to 10wt% of the mass of the pre-fired powder, ensuring the bonding and molding performance between the pre-fired powders, which is conducive to preparing granulated powder with high particle size uniformity, while avoiding excessive binder that would cause the subsequent pressed green body to be too hard, affecting the physicochemical properties of the subsequent ceramic materials, etc.

[0047] In some embodiments, in step (2), the pressure of the pressing molding is 100MPa~200MPa, which is conducive to the full contact of the granulated powder, shrinkage to eliminate pores, and formation of a stable ceramic green body.

[0048] In some embodiments, in step (2), the sintering temperature is 1400℃~1450℃ and the sintering time is 8h~12h, so that the components in the ceramic green body react to form a silicate-based microwave dielectric ceramic material with excellent performance.

[0049] This application also provides an LTCC material comprising a main crystalline phase and a sintering aid; wherein the compositional formula of the main crystalline phase is as follows: A ZrSi2O7, in which A For Ca, Sr, Ba, and solid solution Ca 1-x Sr x solid solution Ca 1-x Ba x or solid solution Sr 1-x Ba x , 0.2≤x≤0.8;

[0050] The above-mentioned sintering aid includes a mixture of 0.33CuO and 0.67H3BO3.

[0051] In some embodiments, the above-mentioned sintering aid also includes one or more of TiO2 and CaTiO3.

[0052] In some embodiments, the amount of the above-mentioned 0.33CuO-0.67H3BO3 mixture added is 5wt%~10wt% of the mass of the main crystalline phase material, which can achieve dense sintering at a lower sintering temperature (850℃~900℃), which is suitable for the temperature requirements of co-firing with Ag, Cu and other electrodes and meets the requirements of LTCC process.

[0053] In a preferred embodiment, the amount of the 0.33CuO-0.67H3BO3 mixture added is 5wt% to 8wt% of the mass of the main crystalline phase material.

[0054] In some embodiments, the amount of TiO2 added is 0wt% to 10wt% of the mass of the main crystalline phase material, preferably 5wt% to 10wt%.

[0055] In some embodiments, the amount of CaTiO3 added is 0wt% to 10wt% of the mass of the main crystalline phase material, preferably 5wt% to 10wt%.

[0056] This application enables the preparation of LTCC materials with medium to low dielectric constant, good quality factor and good temperature coefficient of resonant frequency by adjusting the ratio of pre-fired powder and sintering aid. It is suitable for preparing special ceramic passive microwave devices with complex structures such as LTCC low-pass filters, LTCC band-pass filters, multilayer ceramic substrates, sensors and microelectromechanical systems (MEMS).

[0057] On the other hand, such as Figure 1 As shown, this application also provides a method for preparing the above-mentioned LTCC material, comprising the following steps:

[0058] S1. According to the above composition expression A The raw materials of ZrSi2O7 were prepared according to the stoichiometric ratio, ball-milled, dried, and then pre-calcined to obtain pre-calcined powder.

[0059] S2. The above-mentioned pre-fired powder and the above-mentioned sintering aid are mixed, ball-milled again, dried, mixed with binder, granulated and pressed into shape to obtain a low-temperature co-fired ceramic green body, and then sintered to obtain the above-mentioned LTCC material.

[0060] In some embodiments, in step S1, the raw materials are oxides or carbonates of metal elements, etc. Furthermore, the purity of the raw materials is greater than or equal to 99.5%, which effectively reduces the introduction of impurities and avoids the impact of impurities on the purity and electrochemical performance of the silicate-based microwave dielectric ceramic material. In specific embodiments of this application, the raw material components include CaCO3, SrCO3, BaCO3, ZrO2, and SiO2.

[0061] In some embodiments, in step S1, the ball milling is wet ball milling. The wet ball milling includes the following steps: milling the prepared raw materials, solvent, and milling balls at a mass ratio of 1:(1~2):(3~7) for 10h~15h. The solvent may be, but is not limited to, deionized water. The milling balls may be, but are not limited to, zirconium balls.

[0062] In some embodiments, in step S1, the drying temperature is 70°C to 90°C, and the drying time is 12h to 24h.

[0063] In some embodiments, in step S1, the pre-calcination temperature is 1200℃~1300℃ and the pre-calcination time is 4h~6h, so that the mixed powder is fully mixed and forms a pre-calcined powder with uniformly dispersed components.

[0064] In some embodiments, step S2 includes the following steps:

[0065] S2-1. Prepare the sintering aid raw materials according to the stoichiometric ratio, then mix the above pre-fired powder and the above sintering aid raw materials, and ball mill and dry them again to obtain low-temperature co-fired mixed powder.

[0066] S2-2. Mix the above-mentioned low-temperature co-fired powder and binder and granulate to obtain low-temperature co-fired granulated powder;

[0067] S2-3. Place the above-mentioned low-temperature co-fired granulated powder in a mold and press it into shape to obtain a low-temperature co-fired ceramic green body.

[0068] S2-4. The above-mentioned low-temperature co-fired ceramic green body is sintered to obtain the above-mentioned LTCC material.

[0069] In some embodiments, in step S2-1, the raw materials for the above-mentioned sintering aid are CuO, H3BO3, TiO2, and CaTiO3.

[0070] In some embodiments, in step S2-1, the ball milling is a wet ball milling process. The wet ball milling process includes the following steps: ball milling a mixture of pre-calcined powder and calcination aid powder, a solvent, and milling balls at a mass ratio of 1:(1~2):(3~7) for 10 to 15 hours. The solvent may be, but is not limited to, deionized water. The milling balls may be, but are not limited to, zirconium balls.

[0071] In some embodiments, in step S2-1, the drying temperature is 70°C to 90°C, and the drying time is 12h to 24h.

[0072] In some embodiments, in step S2-2, the binder includes, but is not limited to, at least one of polyvinyl alcohol (PVA) and polyethylene glycol (PEG), which can improve the adhesion between the components and facilitate the molding of the powder into device products. In some embodiments, the amount of the binder is 5wt% to 10wt% of the mass of the low-temperature co-fired mixed powder, ensuring the bonding and molding performance between the pre-fired powders, which is beneficial for preparing low-temperature co-fired granulated powders with high particle size uniformity, while avoiding excessive binder that would cause the subsequently pressed green body to be too hard, affecting the physicochemical properties of the subsequent low-temperature co-fired ceramic materials.

[0073] In some embodiments, in steps S2-3, the pressure of the pressing molding is 100MPa~200MPa, which is conducive to the full contact of the low-temperature co-fired granulated powder, shrinkage to eliminate pores, and formation of a stable low-temperature co-fired ceramic green body.

[0074] In some embodiments, in steps S2-4, the sintering temperature is 850℃~900℃ and the sintering time is 3h~5h.

[0075] This application also provides an application of the above-mentioned LTCC material in the fabrication of LTCC low-pass filters, LTCC band-pass filters, and multilayer ceramic substrates.

[0076] It should be understood that materials of the same or similar type, model, quality, properties, or function as the reagents and instruments used in the following embodiments can be used to implement this application. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0077] The following is an example:

[0078] Examples 1-15

[0079] The method for preparing silicate-based microwave dielectric ceramic materials provided in this application includes the following steps:

[0080] (1) Preparation of mixed powder

[0081] According to chemical formula A ZrSi2O7, in which A For Ca, Sr, Ba and their solid solutions, CaCO3, SrCO3, BaCO3, ZrO2 and SiO2 with a purity of 99.5% are prepared and mixed to obtain a mixed raw material. The mixed raw material is then ball-milled, dried and sieved to obtain a powder with uniform particles.

[0082] The specific processes for ball milling, drying, and sieving are as follows: The mixed raw materials and deionized water are loaded into a polyester ball mill jar containing zirconium balls at a mass ratio of 1:1.5, and ball milled in a planetary ball mill for 12 hours. The ball-milled mixed raw materials are then placed in an 80°C forced-air drying oven for 24 hours to dry, and then the dried mixed raw materials are passed through a 40-mesh sieve.

[0083] (2) Preparation of pre-fired powder

[0084] After the uniformly sized powder prepared in step (1) is placed into an alumina crucible, it is pre-fired in a high-temperature furnace to obtain a main crystalline phase of [missing information]. A Pre-calcined ZrSi2O7 powder.

[0085] The pre-firing heating rate is 5℃ / min, the pre-firing temperature is 1300℃, and the pre-firing time is 5h.

[0086] (3) Preparation of silicate-based microwave dielectric ceramic materials

[0087] The pre-fired powder prepared in step (2) was ball-milled, dried, and sieved to obtain pre-fired ceramic powder. The pre-fired ceramic powder and binder were mixed and granulated, and then placed in a mold for pressing to obtain a ceramic green body. The above ceramic green bodies were sintered at different sintering temperatures to obtain silicate-based microwave dielectric ceramic materials as shown in Table 1.

[0088] The binder is a 5% polyvinyl alcohol (PVA) aqueous solution, and the amount of binder is 8 wt% of the mass of the pre-fired ceramic powder; the pressure for pressing is 150 MPa; the diameter of the ceramic blank is 12 mm and the height of the ceramic blank is 6 mm; the sintering temperature is 1400℃~1450℃ and the sintering time is 10 h.

[0089] Phase analysis of silicate-based microwave dielectric ceramic materials was performed using X-ray diffraction. The XRD patterns of the silicate-based microwave dielectric ceramic materials prepared in Examples 1, 2, 5, 6, and 7 are shown below. Figure 2 .

[0090] The microwave dielectric properties of the above-mentioned silicate-based microwave dielectric ceramic materials were tested using the following methods:

[0091] The above-mentioned silicate-based microwave dielectric ceramic material was polished on a 1000-mesh diamond grinding wheel, then ultrasonically cleaned in deionized water, and finally dried in a 100°C forced-air drying oven for 24 hours. The dielectric constant ε of the sample was analyzed and tested using the parallel plate resonant cavity method. r The test frequency was 9GHz~12GHz. The quality factor of the samples was tested using the resonant cavity method. Q×f The test frequency was 8 GHz. The temperature coefficient of the sample's resonant frequency was obtained by measuring the rate of change of the resonant frequency of the parallel plate resonator with temperature. τ f The temperature range for measurement is 20℃~80℃.

[0092] Table 1. Parameter information and microwave dielectric properties of silicate-based microwave dielectric ceramic materials prepared in Examples 1-15

[0093]

[0094] As can be seen from Table 1, the silicate-based microwave dielectric ceramic material provided in this application has excellent dielectric properties, and its dielectric constant ε r The quality factor is 9-11. Q × f The resonant frequency temperature coefficient ranges from 24,000 GHz to 68,000 GHz. τ fWith a dielectric constant of -35ppm / ℃ to -20ppm / ℃, the low dielectric constant can improve the transmission rate of microwave signals in the medium and alleviate signal delay problems. The high quality factor makes it suitable for manufacturing various special ceramic products, such as dielectric waveguide filters, dielectric resonators and dielectric antennas, and other high-frequency microwave communication devices.

[0095] Examples 16-33

[0096] The method for preparing LTCC material provided in this application includes the following steps:

[0097] (1) The main crystalline phase was prepared according to the method provided in Example 1. A ZrSi2O7 pre-calcined powder was prepared, and then calcination aids CuO and H3BO3, and temperature and frequency regulators TiO2 and CaTiO3 were mixed with the pre-calcined powder according to stoichiometric ratios. Specifically, the addition amount of the 0.33 CuO-0.67 H3BO3 mixture was 5wt%~10wt% of the pre-calcined powder mass, the addition amount of TiO2 was 0wt%~10wt% of the pre-calcined powder mass, and the addition amount of CaTiO3 was 0wt%~10wt% of the pre-calcined powder mass. The mixture was then placed in a ball mill jar containing zirconium balls, and 1.5 times the mass of deionized water was added. The mixture was ball-milled at 350 r / min for 12 h on a planetary ball mill. The ball-milled slurry was dried in an oven at 80℃ for 24 h. After complete drying, the slurry was passed through a 40-mesh nylon sieve to obtain a uniformly sized low-temperature co-fired mixed powder for later use.

[0098] (2) The above-mentioned uniformly granulated low-temperature co-fired mixed powder and 8 wt% binder (5% polyvinyl alcohol PVA aqueous solution) were mixed and granulated to obtain low-temperature co-fired granulated powder. Then, the low-temperature co-fired granulated powder was placed in a mold and pressed into a low-temperature co-fired ceramic green body with a diameter of 12 mm and a height of 6 mm under a pressure of 150 MPa. The above-mentioned low-temperature co-fired ceramic green body was sintered at different sintering temperatures for 3 h to obtain LTCC materials as shown in Table 2.

[0099] Phase analysis of LTCC materials was performed using X-ray diffraction. The XRD pattern of the LTCC material prepared in Example 26 is shown below. Figure 2 The microwave dielectric properties of the LTCC material were tested according to the above method, and the test results are shown in Table 2.

[0100] Table 2. Parameter information and microwave dielectric properties of LTCC materials prepared in Examples 16-33

[0101]

[0102] As shown in Table 2, the sintering temperature of the low-temperature co-fired ceramic material (LTCC material) provided in this application is 850℃~900℃, which is lower than 950℃, meeting the requirements of the LTCC process. Furthermore, the low-temperature co-fired ceramic material provided in this application also possesses a medium to low dielectric constant (ε... r Adjustable from 8.5 to 16), good quality factor ( Q × f Adjustable from 10000GHz to 35000GHz) and with a good temperature coefficient of resonant frequency ( τ f (Adjustable from -40ppm / ℃ to +10ppm / ℃), suitable for fabricating special ceramic passive microwave devices with complex structures such as LTCC low-pass filters, LTCC band-pass filters, multilayer ceramic substrates, sensors, and microelectromechanical systems (MEMS).

[0103] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A silicate-based microwave dielectric ceramic material, characterized in that, The compositional expression of the silicate-based microwave dielectric ceramic material is as follows: A ZrSi2O7, in which A For Ca, Sr, Ba, and solid solution Ca 1-x Sr x solid solution Ca 1-x Ba x or solid solution Sr 1- x Ba x , 0.2≤x≤0.8; the dielectric constant of the silicate-based microwave dielectric ceramic material is 9~11, the quality factor is 24000GHz~68000GHz, and the temperature coefficient of the resonant frequency is -35ppm / ℃~-20ppm / ℃.

2. A method for preparing a silicate-based microwave dielectric ceramic material according to claim 1, characterized in that, Includes the following steps: (1) According to the composition expression A The raw materials of ZrSi2O7 were prepared according to the stoichiometric ratio, ball-milled and dried, and then pre-calcined at 1200℃~1300℃ for 4h~6h to obtain pre-calcined powder. (2) The pre-fired powder is ball-milled again, dried and mixed with binder to granulate and pressed to obtain ceramic green body, and then sintered at 1400℃~1450℃ for 8h~12h to obtain the silicate-based microwave dielectric ceramic material.

3. An LTCC material, characterized in that, The LTCC material comprises a main crystalline phase and a sintering aid; wherein the main crystalline phase is a silicate-based microwave dielectric ceramic, and its composition formula is as follows: A ZrSi2O7, in which A For Ca, Sr, Ba; The sintering aid comprises a mixture of 0.33CuO and 0.67H3BO3, wherein the amount of the 0.33CuO-0.67H3BO3 mixture added is 5wt% to 10wt% of the mass of the main crystalline phase.

4. The LTCC material according to claim 3, characterized in that, The sintering aid also includes TiO2 and / or CaTiO3.

5. The LTCC material according to claim 4, characterized in that, The amount of TiO2 added is 0wt% to 10wt% of the mass of the main crystalline phase, and is not 0; and / or, The amount of CaTiO3 added is 0wt% to 10wt% of the mass of the main crystalline phase, and is not 0.

6. A method for preparing an LTCC material according to any one of claims 3 to 5, characterized in that, Includes the following steps: S1. According to the composition expression A The raw materials of ZrSi2O7 were prepared according to the stoichiometric ratio, ball-milled and dried, and then pre-calcined at 1200℃~1300℃ for 4h~6h to obtain pre-calcined powder. S2. The pre-fired powder and the sintering aid are mixed, ball-milled again, dried, mixed with binder, granulated and pressed to obtain a low-temperature co-fired ceramic green body, and then sintered at 850℃~900℃ for 3h~5h to obtain the LTCC material.

7. The use of an LTCC material according to any one of claims 3 to 5 in the fabrication of LTCC low-pass filters, LTCC band-pass filters, and multilayer ceramic substrates.

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