Ba5Nb4O15-based low-temperature co-fired ceramic material and preparation method of ceramic substrate

Abstract

The invention provides a Ba5Nb4O15-based low-temperature co-fired ceramic material and a preparation method of a ceramic substrate, and the Ba5Nb4O15-based low-temperature co-fired ceramic material comprises the following components in percentage by mass: 98wt%-99wt% of Ba5Nb4O15 ceramic powder, 0.5 wt%-2wt% of glass powder and 0-1wt% of an oxide sintering aid. The low-melting-point glass powder is introduced to reduce the sintering temperature of the Ba5Nb4O15 ceramic powder to 900 DEG C or below, and the temperature coefficient of resonance frequency of the Ba5Nb4O15 ceramic powder is effectively adjusted by adding the oxide sintering aid; the Ba5Nb4O15-based low-temperature co-fired ceramic substrate can be sintered at the temperature of 850-900 DEG C, is good in compactness, can be matched and co-fired with gold, silver and other electrodes, and has the dielectric constant of 39-42, the Q * f value of 12000-25000GHz and the temperature coefficient of resonance frequency of-10-30ppm / DEG C.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-temperature co-fired ceramic materials, and particularly relates to a preparation method of a Ba5Nb4O 15 -based low-temperature co-fired ceramic material and a ceramic substrate. Background Art

[0002] Since the low-temperature co-fired ceramic (LTCC) technology was proposed by Hughes Company of the United States in 1982, due to its advantages of realizing multilayer circuit integration and miniaturization, it has become one of the core technologies in the modern wireless communication field. The LTCC process mainly makes a green tape with a certain thickness from a low-temperature ceramic system material by the tape casting method, and then makes a green ceramic through processes such as punching, via wiring, component printing, hot pressing lamination, and green ceramic slicing. Then, a high-density and miniaturized circuit board or passive component is realized through low-temperature sintering, and it can be widely used in modern mobile communication, satellite broadcasting, radio remote control and other fields. At present, the methods for reducing the sintering temperature of microwave dielectric ceramics include adding low-melting-point sintering aids (oxides, low-melting-point glasses), using ultra-fine powder raw materials, and improving the material synthesis process. Among them, adding low-melting-point sintering aids is currently the most effective and cost-effective method for reducing the sintering temperature.

[0003] Low-temperature co-fired microwave dielectric ceramics are a kind of functional ceramic materials dedicated to the manufacture of high-frequency electronic devices. The core lies in that they can be co-fired with highly conductive metals at low temperatures and at the same time have excellent microwave dielectric properties. Ba5Nb4O 15 As a typical microwave dielectric ceramic with a medium dielectric constant, it has been widely studied due to its excellent quality factor. It has been reported in the literature that this ceramic sintered at 1380 °C for 4 h obtained a dielectric constant (ε r ) ≈ 40.75, a quality factor (Q*f) ≈ 29,418 GHz, and a frequency temperature coefficient (τ f ) ≈ +79.8 ppm / °C. However, the intrinsic sintering temperature of Ba5Nb4O 15 ceramics is as high as 1380 °C, far exceeding the melting points of conductors such as silver (961 °C) and copper (1085 °C), and it cannot be co-fired with silver and copper conductor pastes; moreover, Ba5Nb4O 15 ceramics have a large frequency temperature coefficient (τ f ) ≈ +79.8 ppm / °C, resulting in poor temperature stability of the device. In the existing improvement scheme, adding 1.5 wt% of BaCu(B2O5) can reduce the sintering temperature to 875 °C, but τ f is still as high as +60 ppm / °C; V 5+ has been proven to be able to replace Nb 5+ , and can improve Ba5Nb4O 15The microwave dielectric properties of ceramics, but V2O5 needs to be further processed to be applicable to the tape casting process. Otherwise, it is prone to gelation reaction with the binder and requires additional surface coating treatment, increasing the process complexity. The current technology faces dual challenges, that is, to reduce the sintering temperature of Ba5Nb4O 15 to the co-firing range of conductors (≤900 °C) through sintering aids, and at the same time synchronously regulate its τ f to a near-zero value, and at the same time must have excellent dielectric constant and quality factor without significant deterioration.

[0004] Therefore, it is necessary to provide an improved technical solution for the deficiencies of the above-mentioned existing technologies. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the existing technologies, the purpose of the present invention is to provide a method for preparing a Ba5Nb4O 15 -based low-temperature co-fired ceramic material and a ceramic substrate, which can reduce its sintering temperature to the co-firing range of conductors without reducing the dielectric constant and quality factor of the ceramic material, and at the same time effectively adjust the temperature coefficient of the resonant frequency of the ceramic material.

[0006] To achieve the above purpose and other related purposes, the present invention provides a Ba5Nb4O 15 -based low-temperature co-fired ceramic material, and the ceramic material includes Ba5Nb4O 15 ceramic powder, glass powder and oxide sintering aid; calculated by the mass percentage of the ceramic material, the ceramic material includes 98wt% - 99wt% of Ba5Nb4O 15 ceramic powder, 0wt% - 2wt% of glass powder and 0 - 1wt% of oxide sintering aid.

[0007] As an example, the preparation method of the Ba5Nb4O 15 ceramic powder specifically includes: adding ceramic raw material powders BaCO3 and Nb2O5 in a molar ratio of 5:2 to a ball mill tank for the first ball milling and mixing, drying to obtain a mixed material; then subjecting the mixed material to high-temperature calcination at 900 - 1100 °C to synthesize the main crystal phase Ba5Nb4O 15 phase, and then putting it into the ball mill tank again for the second ball milling and drying to obtain Ba5Nb4O 15 ceramic powder.

[0008] As an example, the glass powder includes one or a combination of BaO-ZnO-B2O3-SiO2-Li2O glass powder and ZnO-B2O3-SiO2 glass powder.

[0009] As an example, based on the mass percentage of the BaO-ZnO-B2O3-SiO2-Li2O glass powder, the BaO-ZnO-B2O3-SiO2-Li2O glass powder comprises 30 wt% to 60 wt% of BaO, 0 to 10 wt% of ZnO, 20 wt% to 50 wt% of B2O3, 10 wt% to 20 wt% of SiO2, and 0 to 5 wt% of Li2O.

[0010] As an example, the preparation method of the BaO-ZnO-B2O3-SiO2-Li2O glass powder specifically comprises: weighing BaO, ZnO, B2O3, SiO2, and Li2O according to the mass percentage of the raw materials, placing them in a mixer for thorough mixing, melting at 1200 to 1400 °C for 1 to 3 h to obtain a glass melt; quenching the glass melt to obtain glass fragments; then placing the glass fragments into a ball mill tank for ball milling, drying, and sieving through a 20- to 80-mesh sieve to obtain the BaO-ZnO-B2O3-SiO2-Li2O glass powder.

[0011] As an example, based on the mass percentage of the ZnO-B2O3-SiO2 glass powder, the ZnO-B2O3-SiO2 glass powder comprises 20 wt% to 40 wt% of ZnO, 30 wt% to 65 wt% of B2O3, and 5 wt% to 15 wt% of SiO2.

[0012] As an example, the preparation method of the ZnO-B2O3-SiO2 glass powder specifically comprises: weighing ZnO, B2O3, and SiO2 according to the mass percentage of the raw materials, placing them in a mixer for thorough mixing, melting at 1000 to 1200 °C for 1 to 3 h to obtain a glass melt; quenching the glass melt to obtain glass fragments; then placing the glass fragments into a ball mill tank for ball milling, drying, and sieving through a 20- to 80-mesh sieve to obtain the ZnO-B2O3-SiO2 glass powder.

[0013] As an example, the oxide sintering aid includes one or a combination of Ba-V-Cu and BiVO4.

[0014] As an example, the preparation method of the Ba-V-Cu oxide sintering aid includes: adding BaCO3, V2O5, and CuO in a molar ratio of 1:1:1 to a ball mill tank, performing the first ball milling and mixing, drying to obtain a mixture; then calcining the mixture at 700 to 850 °C, and then putting it into the ball mill tank again for the second ball milling and drying to obtain the Ba-V-Cu oxide sintering aid.

[0015] As an example, the preparation method of the BiVO4 oxide sintering aid includes: adding Bi2O3 and V2O5 in a molar ratio of 1:1 into a ball milling tank, conducting the first ball milling and mixing, and drying to obtain a mixed material; then calcining the mixed material at 500-750 °C, and then putting it into the ball milling tank again for the second ball milling and drying to obtain the BiVO4 oxide sintering aid.

[0016] In addition, the present invention also provides a Ba5Nb4O 15 based low-temperature co-fired ceramic substrate, and the Ba5Nb4O 15 based low-temperature co-fired ceramic substrate includes the above-mentioned Ba5Nb4O 15 based low-temperature co-fired ceramic material.

[0017] The present invention also provides a preparation method of the above-mentioned Ba5Nb4O 15 based low-temperature co-fired ceramic substrate, and the preparation method includes the following steps:

[0018] S1. Provide the above-mentioned Ba5Nb4O 15 based low-temperature co-fired ceramic material, weigh the Ba5Nb4O 15 ceramic powder, glass powder and oxide sintering aid according to the ratio, add them into a ball milling tank for ball milling and mixing for 1-4 h, dry and then screen through a 60-80 mesh sieve to obtain the Ba5Nb4O 15 based low-temperature co-fired ceramic material;

[0019] S2. Add a dispersant and an organic solvent to the Ba5Nb4O 15 based low-temperature co-fired ceramic material for the first ball milling and mixing, and then add a plasticizer, a binder and a leveling agent for the second ball milling and mixing to obtain a casting slurry, and cast and form it into a Ba5Nb4O 15 based low-temperature co-fired green tape;

[0020] S3. Stack and isostatically press the Ba5Nb4O 15 based LTCC green tape to form a green body, and sinter the green body at 850 °C - 900 °C to prepare a Ba5Nb4O 15 based low-temperature co-fired ceramic substrate.

[0021] As an example, for the prepared Ba5Nb4O 15 based low-temperature co-fired ceramic substrate at a test frequency of 5 GHz, the dielectric constant of the Ba5Nb4O 15 based low-temperature co-fired ceramic substrate is 39-42, the Q*f value is 12000-25000 GHzGHz, and the resonance frequency temperature coefficient is -10-30 ppm / °C.

[0022] As described above, the Ba5Nb4O of the present invention15 Preparation method of Ba5Nb4O-based low-temperature co-fired ceramic material and ceramic substrate, having the following

[0023] Beneficial effects:

[0024] The Ba5Nb4O in the present invention 15 The Ba5Nb4O-based low-temperature co-fired ceramic material includes Ba5Nb4O 15 ceramic powder, glass powder and oxide sintering aid. By introducing low-melting glass powder, the sintering temperature of Ba5Nb4O 15 ceramic powder is reduced to 900 °C and below. The resonance frequency temperature coefficients of the low-melting oxide sintering aids are all negative values. The addition of the oxide sintering aid can effectively adjust the resonance frequency temperature coefficient of the low-temperature co-fired ceramic material; moreover, the adopted oxide sintering aids have all been calcined, which can effectively reduce the gel reaction with the binder when preparing the casting slurry and improve the stability of the casting slurry; at the same time, the raw materials of the oxide sintering aid are all common oxides, the raw materials are cheap, easy to obtain, pollution-free, and the preparation method is simple.

[0025] The Ba5Nb4O in the present invention 15 The Ba5Nb4O-based low-temperature co-fired ceramic substrate can be sintered at 850 °C to 900 °C, and has good densification. It can be co-fired with electrodes such as gold and silver. The dielectric constant is 39 to 42, the Q*f value is 12000 to 25000 GHz, and the resonance frequency temperature coefficient is -10 to 30 ppm / °C, which has practical application value in microwave devices. Specific embodiments

[0026] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] Before further describing the specific embodiments of the present invention, it should be understood that the protection scope of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the embodiments of the present invention are for describing specific embodiments, rather than for limiting the protection scope of the present invention. The test methods without specific conditions mentioned in the following examples are usually carried out under conventional conditions or according to the conditions recommended by each manufacturer.

[0028] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art of this technology. In addition to the specific methods, equipment, and materials used in the embodiments, according to the knowledge of those skilled in the art of this technology and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to those described in the embodiments of the present invention can also be used to implement the present invention.

[0029] The present invention provides a Ba5Nb4O 15 -based low-temperature co-fired ceramic material, and the low-temperature co-fired ceramic material includes Ba5Nb4O 15 ceramic powder, glass powder, and an oxide sintering aid; calculated by the mass percentage of the low-temperature co-fired ceramic material, the low-temperature co-fired ceramic material includes 98 wt% to 99 wt% of Ba5Nb4O 15 ceramic powder, 0 wt% to 2 wt% of glass powder, and 0 to 1 wt% of oxide sintering aid.

[0030] Specifically, in the low-temperature co-fired ceramic material, the mass percentage of Ba5Nb4O 15 ceramic powder can include any value within the range such as 98 wt%, 98.2 wt%, 98.5 wt%, 98.7 wt%, 99 wt%, etc.; the mass percentage of glass powder can include any value within the range such as 0, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, etc.; the mass percentage of oxide sintering aid can include any value within the range such as 0, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, etc.

[0031] As an example, the preparation method of Ba5Nb4O 15 ceramic powder specifically includes: adding ceramic raw material powders BaCO3 and Nb2O5 in a molar ratio of 5:2 into a ball mill tank for the first ball milling and mixing, and drying to obtain a mixed material; then carrying out high-temperature calcination of the mixed material at 900 - 1100 °C to synthesize the main crystal phase Ba5Nb4O 15 phase, and then putting it into the ball mill tank again for the second ball milling and drying, to obtain Ba5Nb4O 15 ceramic powder.

[0032] Specifically, the mixed material after mixing the raw materials of Ba5Nb4O 15 ceramic powder needs to be subjected to high-temperature calcination, and the temperature of high-temperature calcination can include any value within the range such as 900 °C, 950 °C, 1000 °C, 1050 °C, 1100 °C, etc.; after calcination, it is ball milled again to obtain Ba5Nb4O15 The D50 particle size of the ceramic powder is 0.5 μm to 1.2 μm (such as 0.5 μm, 0.8 μm, 1.0 μm, 1.1 μm, 1.2 μm, etc.).

[0033] As an example, the glass powder includes one or a combination of BaO-ZnO-B2O3-SiO2-Li2O glass powder and ZnO-B2O3-SiO2 glass powder.

[0034] As an example, in terms of the mass percentage of BaO-ZnO-B2O3-SiO2-Li2O glass powder, the BaO-ZnO-B2O3-SiO2-Li2O glass powder includes 30 wt% to 60 wt% (such as 30 wt%, 40 wt%, 50 wt%, 60 wt%, etc.) of BaO, 0 to 10 wt% (such as 0, 2 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, etc.) of ZnO, 20 wt% to 50 wt% (such as 20 wt%, 30 wt%, 40 wt%, 50 wt%, etc.) of B2O3, 10 wt% to 20 wt% (such as 10 wt%, 12 wt%, 14 wt%, 15 wt%, 16 wt%, 18 wt%, 20 wt%, etc.) of SiO2, and 0 to 5 wt% (such as 0, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, etc.) of Li2O.

[0035] As an example, the preparation method of BaO-ZnO-B2O3-SiO2-Li2O glass powder specifically includes: weighing BaO, ZnO, B2O3, SiO2, and Li2O according to the mass percentage of the raw materials, placing them in a mixer and mixing thoroughly, then melting at 1200 to 1400 °C for 1 to 3 h to obtain a glass melt; quenching the glass melt to obtain glass slag; then placing the glass slag in a ball mill tank for ball milling and drying, and sieving with a 20 to 80 mesh sieve to obtain BaO-ZnO-B2O3-SiO2-Li2O glass powder.

[0036] Specifically, the mixer used for mixing the raw materials is a three-dimensional mixer, and after mixing, it is placed in a platinum crucible for melting. The melting temperature can include any value within the range such as 1200 °C, 1250 °C, 1300 °C, 1350 °C, 1400 °C, etc., and the melting time can include 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc.; then the quenched glass slag is placed in an alumina ball mill tank, using high-purity alcohol as the ball milling medium, ball milling for 6 to 12 h (such as 6 h, 8 h, 10 h, 12 h, etc.), then drying for 4 to 8 h (such as 4 h, 5 h, 6 h, 7 h, 8 h, etc.), and obtaining BaO-ZnO-B2O3-SiO2-Li2O glass powder after sieving.

[0037] As an example, in terms of mass percentage of ZnO-B2O3-SiO2 glass powder, the ZnO-B2O3-SiO2 glass powder includes 20wt% to 40wt% (for example, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, etc.) of ZnO, 30wt% to 65wt% (for example, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt%, etc.) of B2O3 and 5wt% to 15wt% (for example, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, etc.) of SiO2.

[0038] As an example, the preparation method of the ZnO-B2O3-SiO2 glass powder specifically includes: weighing ZnO, B2O3 and SiO2 according to the mass percentage of the raw materials, placing them in a three-dimensional mixer and fully mixing them, and then melting them at 1000-1200°C for 1-3 hours to obtain a glass melt; quenching the glass melt to obtain glass slag; then placing the glass slag in a ball mill, ball milling, drying, and sieving with a 20-80 mesh sieve to obtain ZnO-B2O3-SiO2 glass powder.

[0039] Specifically, when preparing ZnO-B2O3-SiO2 glass powder, the temperature for melting the raw materials after mixing may include any value within the range of 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, etc., and the melting time may include 1h, 2h, 3h, etc., to obtain a glass melt, and the glass melt is quenched to obtain glass slag; then, the glass slag is placed in a ball mill, and high-purity alcohol is used as a ball milling medium for ball milling for 6 to 12 hours (such as 6h, 8h, 10h, 12h, etc.), and then dried for 4 to 8 hours (such as 4h, 5h, 6h, 7h, 8h, etc.), and sifted through a 20-80 mesh sieve to obtain ZnO-B2O3-SiO2 glass powder.

[0040] As an example, the oxide sintering aid includes one or a combination of Ba-V-Cu and BiVO4.

[0041] Preferably, the oxide sintering aid is Ba-V-Cu.

[0042] As an example, the preparation method of the Ba-V-Cu oxide sintering aid includes: adding BaCO3, V2O5, and CuO in a molar ratio of 1:1:1 into a ball mill, performing a first ball milling mixing, and drying to obtain a mixture; then calcining the mixture at 700-850°C, and then putting it into the ball mill again for a second ball milling and drying to obtain the Ba-V-Cu oxide sintering aid.

[0043] Specifically, the mixture obtained after the first ball milling and mixing needs to be calcined at a high temperature. The calcination temperature can include any value within a range such as 700 °C, 750 °C, 800 °C, 850 °C, etc. After calcination, it is subjected to the second ball milling and drying. The purpose of ball milling and drying is to control the particle size of the obtained Ba-V-Cu oxide sintering aid. Regarding the rate of each ball milling, the drying temperature, time, etc., no excessive restrictions are imposed here, as long as it can meet the actual requirements. The D50 particle size of the finally prepared Ba-V-Cu oxide sintering aid is 0.5 μm to 1.5 μm (such as 0.5 μm, 1.0 μm, 1.2 μm, 1.5 μm, etc.).

[0044] As an example, the preparation method of the BiVO4 oxide sintering aid includes: adding Bi2O3 and V2O5 in a molar ratio of 1:1 to a ball milling tank, performing the first ball milling and mixing, and drying to obtain a mixture; then calcining the mixture at 500 - 750 °C (such as 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C, etc.), and then putting it into the ball milling tank again for the second ball milling and drying to obtain a BiVO4 oxide sintering aid with a smaller particle size.

[0045] Specifically, the D50 particle size of the prepared BiVO4 oxide sintering aid is 0.5 μm to 1.5 μm (such as 0.5 μm, 1.0 μm, 1.2 μm, 1.5 μm, etc.).

[0046] The present invention also provides a Ba5Nb4O 15 -based low-temperature co-fired ceramic substrate, and the Ba5Nb4O 15 -based low-temperature co-fired ceramic substrate includes the above-mentioned Ba5Nb4O 15 -based low-temperature co-fired ceramic material.

[0047] In addition, the present invention also provides a preparation method of the above-mentioned Ba5Nb4O 15 -based low-temperature co-fired ceramic substrate, and the preparation method includes the following steps:

[0048] S1. Provide the above-mentioned Ba5Nb4O 15 -based low-temperature co-fired ceramic material, weigh the Ba5Nb4O 15 ceramic powder, glass powder and oxide sintering aid according to the ratio, add them to a ball milling tank for ball milling and mixing for 1 - 4 h, dry and then pass through a 60 - 80 mesh sieve to obtain the Ba5Nb4O 15 -based low-temperature co-fired ceramic powder;

[0049] S2. At Ba5Nb4O 15The base low-temperature co-fired ceramic powder is added with a dispersant and an organic solvent for the first ball milling and mixing, and then a plasticizer, a binder and a leveling agent are added for the second ball milling and mixing to obtain a casting slurry, and the casting slurry is cast into a Ba5Nb4O 15 base LTCC green tape;

[0050] S3. The Ba5Nb4O 15 base LTCC green tape is laminated and isostatically pressed to form a green body, and the green body is sintered at 850 °C to 900 °C to prepare a Ba5Nb4O 15 base low-temperature co-fired ceramic substrate.

[0051] Specifically, when the raw materials are added to the ball mill for ball milling in step S1, high-purity alcohol is used as the ball milling medium, and the ball milling time can include any value in the range such as 1 h, 2 h, 3 h, 4 h, etc., and it is dried for 4 to 8 h (such as 4 h, 5 h, 6 h, 7 h, 8 h, etc.); in step S2, when preparing the casting slurry, a dispersant and an organic solvent are first added for the first ball milling and mixing for 1 to 3 h (such as 1 h, 2 h, 3 h), and then a plasticizer, a binder and a leveling agent are added for the second ball milling and mixing for 1 to 3 h (such as 1 h, 2 h, 3 h). The specific components and addition amounts of the dispersant, organic solvent, plasticizer, binder, and leveling agent are not overly restricted here, as long as a casting slurry with good fluidity can be formed, and the components commonly used in practical applications are preferably selected; when performing casting forming, the thickness of the green tape is controlled by adjusting the height of the doctor blade and the running speed of the carrier film. The specific thickness is not restricted here and is adjusted according to actual needs.

[0052] Specifically, the number of laminated layers in step S3 is 10 to 20 layers, and the sintering temperature can include any value in the range such as 850 °C, 860 °C, 870 °C, 880 °C, 890 °C, 900 °C, etc. Preferably, the sintering time is 2 to 4 h (such as 2 h, 3 h, 4 h, etc.). In addition, after the green body is cut into samples of a certain size, it is placed on an alumina firing plate and put into a muffle furnace. First, it is slowly heated from room temperature to 450 °C to 550 °C at a heating rate of 1 °C / min and held for 2 hours for debinding to completely remove the organic components in the sample, and then it is rapidly heated to 850 °C to 900 °C at a heating rate of 5 °C / min and sintered for 2 to 4 h. After cooling to room temperature with the furnace, the Ba5Nb4O 15 base LTCC substrate is prepared.

[0053] As an example, for the prepared Ba5Nb4O 15 base low-temperature co-fired ceramic substrate, at a test frequency of 5 GHz, the Ba5Nb4O 15The dielectric constant of the low-temperature co-fired ceramic substrate is 39 to 42, the Q*f value is 12000 to 25000 GHz, and the resonant frequency temperature coefficient is -10 to 30 ppm / °C.

[0054] In order to better understand the present invention, Ba5Nb4O 15 The preparation method of the low temperature co-fired ceramic material and the ceramic substrate is described below with reference to the specific examples. 15 The present invention is described in detail below. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0055] The Ba5Nb4O 15 The preparation method of ceramic powder is as follows: adding ceramic raw material powder BaCO3 and Nb2O5 in a molar ratio of 5:2 into a ball mill for the first ball milling and drying to obtain a mixture; then calcining the mixture at 1000°C to synthesize the main crystal phase Ba5Nb4O 15 phase, and then put it into the ball mill again for the second ball milling and drying to obtain Ba5Nb4O with a D50 particle size of 0.5μm to 1.2μm. 15 Ceramic powder.

[0056] The preparation method of the BaO-ZnO-B2O3-SiO2-Li2O glass powder used in the following embodiments is specifically as follows: BaO, ZnO, B2O3, SiO2 and Li2O are weighed according to the mass percentage of the raw materials, placed in a mixer and fully mixed, and then melted at 1350°C for 2 hours to obtain a glass melt; the glass melt is quenched to obtain glass slag; the glass slag is then placed in a ball mill, ball milled, dried, and sieved with a 20-80 mesh screen to obtain BaO-ZnO-B2O3-SiO2-Li2O glass powder; wherein, based on the mass percentage of the BaO-ZnO-B2O3-SiO2-Li2O glass powder, the BaO-ZnO-B2O3-SiO2-Li2O glass powder includes 41wt% of BaO, 6wt% of ZnO, 40wt% of B2O3, 12wt% of SiO2 and 1wt% of Li2O.

[0057] The preparation method of the ZnO-B2O3-SiO2 glass powder used in the following examples specifically includes: weighing ZnO, B2O3, and SiO2 according to the mass percentages of the raw materials, placing them in a mixer and mixing thoroughly, then melting at 1000 °C for 3 h to obtain a glass melt; quenching the glass melt to obtain glass fragments; then placing the glass fragments into a ball mill tank for ball milling, drying, and sieving through a 20-80 mesh sieve to obtain ZnO-B2O3-SiO2 glass powder; among them, calculated by the mass percentage of the ZnO-B2O3-SiO2 glass powder, the ZnO-B2O3-SiO2 glass powder includes 35 wt% ZnO, 55 wt% B2O3, and 10 wt% SiO2.

[0058] The preparation method of the Ba-V-Cu oxide sintering aid used in the following examples is specifically as follows: adding BaCO3, V2O5, and CuO in a molar ratio of 1:1:1 to a ball mill tank, carrying out the first ball milling and mixing, and drying to obtain a mixed material; then calcining the mixed material at 800 °C, and then putting it into the ball mill tank again for the second ball milling and drying to obtain a Ba-V-Cu sintering aid powder with a D50 particle size of 0.5 μm to 1.5 μm.

[0059] The preparation method of the BiVO4 oxide sintering aid used in the following examples is specifically as follows: adding Bi2O3 and V2O5 in a molar ratio of 1:1 to a ball mill tank, carrying out the first ball milling and mixing, and drying to obtain a mixed material; then calcining the mixed material at 600 °C, and then putting it into the ball mill tank again for the second ball milling and drying to obtain a BiVO4 sintering aid powder with a D50 particle size of 0.5 μm to 1.5 μm.

[0060] Examples 1 to 7

[0061] Examples 1 to 7 of the present invention provide a Ba5Nb4O 15 based low-temperature co-fired ceramic material, which includes Ba5Nb4O 15 ceramic powder, glass powder, and oxide sintering aid; among them, the glass powder includes one or a combination of BaO-ZnO-B2O3-SiO2-Li2O glass powder and ZnO-B2O3-SiO2 glass powder; the oxide sintering aid includes one or a combination of Ba-V-Cu, CuO, and BiVO4; calculated by the mass percentage of the low-temperature co-fired ceramic material, the raw material ratio of the low-temperature co-fired ceramic material refers to the ratio listed in Table 1.

[0062] Table 1. Raw material ratio of the Ba5Nb4O 15 based low-temperature co-fired ceramic material in Examples 1 to 7

[0063]

[0064] Examples 1 to 7 also provide a method for preparing the above-mentioned Ba5Nb4O 15 based low-temperature co-fired ceramic substrate, including the following steps:

[0065] S1. Weigh each raw material according to the raw material ratio in Table 1, add it to a ball mill tank, use high-purity alcohol as the ball milling medium for ball milling and mixing for 4 h, dry it for 6 h, and then screen it through a 60-80 mesh sieve to obtain Ba5Nb4O 15 based low-temperature co-fired ceramic material;

[0066] S2. Add a dispersant and an organic solvent to the Ba5Nb4O 15 based low-temperature co-fired ceramic material for the first ball milling for 3 h, and then add a plasticizer, a binder and a leveling agent for the second ball milling and mixing for 3 h to obtain a casting slurry. Vacuum degas the casting slurry, control the thickness by adjusting the hanging height and the running speed of the carrier film, and cast and form a Ba5Nb4O 15 based LTCC green tape with a thickness of 90 μm;

[0067] S3. Cut the Ba5Nb4O 15 based LTCC green tape into small pieces of 80 mm × 80 mm, select 10 pieces for lamination and isostatic pressing to form a green body; cut the green body into samples of 60 mm × 60 mm, place the samples on an alumina sintering plate, and then put them into a muffle furnace. Slowly heat from room temperature at a heating rate of 1 ° / min to 550 °C, keep the temperature for 2 h to completely remove the organic components in the samples, and then quickly heat to the sintering temperature (the sintering temperatures in each example are shown in Table 2) at a heating rate of 5 ° / min, sinter for 2 h, and cool to room temperature with the furnace to prepare a Ba5Nb4O 15 based low-temperature co-fired ceramic substrate.

[0068] Performance test:

[0069] Under the condition of 5 GHz, evaluate the microwave dielectric properties of the Ba5Nb4O 15 based low-temperature co-fired ceramic substrates in Examples 1 to 7 above, and obtain the dielectric constant, Q*f value and resonant frequency temperature coefficient respectively, as shown in Table 2.

[0070] Table 2. Evaluation results of microwave dielectric properties of Ba5Nb4O 15 based low-temperature co-fired ceramic substrates prepared in Examples 1 to 7

[0071]

[0072] According to the data results in Examples 1 to 7, it can be seen that the glass powder and low-melting-point oxide sintering aids selected in the present invention can effectively reduce Ba5Nb4O15 The sintering temperature of the Ba5Nb4O-based low-temperature co-fired ceramic material promotes ceramic densification, Ba5Nb4O 15 -based low-temperature co-fired ceramics have excellent dielectric properties and a near-zero resonant frequency temperature coefficient.

[0073] In summary, the Ba5Nb4O in the present invention 15 -based low-temperature co-fired ceramic material includes Ba5Nb4O 15 ceramic powder, glass powder and oxide sintering aids. By introducing low-melting glass powder, the sintering temperature of Ba5Nb4O 15 ceramic powder is reduced to 900 °C and below. The resonant frequency temperature coefficients of the low-melting oxide sintering aids are all negative. The addition of the oxide sintering aids can effectively adjust the resonant frequency temperature coefficient of the low-temperature co-fired ceramic material; moreover, the oxide sintering aids used have all been calcined, which can effectively reduce the gel reaction with the binder when preparing the tape-casting slurry and improve the stability of the tape-casting slurry; at the same time, the raw materials of the oxide sintering aids are all common oxides, the raw materials are cheap and easy to obtain, pollution-free, and the preparation method is simple; the Ba5Nb4O 15 -based low-temperature co-fired ceramic substrate can be sintered at 850 °C to 900 °C, and has good densification. It can be co-fired with electrodes such as gold and silver, the dielectric constant is 39 - 42, the Q*f value is 12000 - 25000 GHz, and the resonant frequency temperature coefficient is -10 - 30 ppm / °C, which has practical application value in microwave devices. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0074] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A Ba5Nb4O 15 Based low temperature co-fired ceramic material, characterized in that, The ceramic material includes Ba5Nb4O 15 Ceramic powder, glass powder and oxide sintering aid; in terms of the mass percentage of the ceramic material, the ceramic material comprises 98wt% to 99wt% of Ba5Nb4O 15 Ceramic powder, 0wt% to 2wt% of glass powder and 0 to 1wt% of oxide sintering aid.

2. Ba5Nb4O according to claim 1 15 Based low temperature co-fired ceramic material, characterized in that: The Ba5Nb4O 15 The preparation method of ceramic powder specifically includes: The ceramic raw material powder BaCO3 and Nb2O5 are added into a ball mill according to a molar ratio of 5:2 for the first ball milling and drying to obtain a mixture; the mixture is then calcined at 900-1100°C to synthesize the main crystal phase Ba5Nb4O 15 phase, and then put it into the ball mill again for the second ball milling and drying to obtain Ba5Nb4O 15 Ceramic powder.

3. Ba5Nb4O according to claim 1 15 Based low temperature co-fired ceramic material, characterized in that: The glass powder includes one or a combination of BaO-ZnO-B2O3-SiO2-Li2O glass powder and ZnO-B2O3-SiO2 glass powder.

4. Ba5Nb4O according to claim 3 15 Based low temperature co-fired ceramic material, characterized in that: Includes one or a combination of the following conditions: Measured by the mass percentage of the BaO-ZnO-B2O3-SiO2-Li2O glass powder, the BaO-ZnO-B2O3-SiO2-Li2O glass powder comprises 30wt% to 60wt% of BaO, 0 to 10wt% of ZnO, 20wt% to 50wt% of B2O3, 10wt% to 20wt% of SiO2 and 0 to 5wt% of Li2O; Calculated by mass percentage of the ZnO-B2O3-SiO2 glass powder, the ZnO-B2O3-SiO2 glass powder includes 20wt% to 40wt% of ZnO, 30wt% to 65wt% of B2O3 and 5wt% to 15wt% of SiO2.

5. Ba5Nb4O according to claim 4 15 Based low temperature co-fired ceramic material, characterized in that: Includes one or a combination of the following conditions: The preparation method of the BaO-ZnO-B2O3-SiO2-Li2O glass powder specifically comprises: weighing BaO, ZnO, B2O3, SiO2 and Li2O according to the mass percentage of the raw materials, placing them in a mixer and mixing them thoroughly, and then melting them at 1200-1400° C. for 1-3 hours to obtain a glass melt; quenching the glass melt to obtain glass slag; then placing the glass slag in a ball mill, ball milling, drying, and sieving with a 20-80 mesh screen to obtain BaO-ZnO-B2O3-SiO2-Li2O glass powder; The preparation method of the ZnO-B2O3-SiO2 glass powder specifically includes: weighing ZnO, B2O3 and SiO2 according to the mass percentage of the raw materials, placing them in a mixer and mixing them thoroughly, and then melting them at 1000-1200°C for 1-3 hours to obtain a glass melt; quenching the glass melt to obtain glass slag; then placing the glass slag in a ball mill, ball milling, drying, and sieving with a 20-80 mesh screen to obtain ZnO-B2O3-SiO2 glass powder.

6. Ba5Nb4O according to claim 1 15 Based low temperature co-fired ceramic material, characterized in that: The oxide sintering aid includes one or a combination of Ba-V-Cu and BiVO4.

7. Ba5Nb4O according to claim 6 15 Based low temperature co-fired ceramic material, characterized in that: Includes one or a combination of the following conditions: The preparation method of the Ba-V-Cu oxide sintering aid comprises: adding BaCO3, V2O5 and CuO in a ball mill at a molar ratio of 1:1:1, performing a first ball milling and mixing, and drying to obtain a mixture; then calcining the mixture at 700-850° C., and then putting the mixture into the ball mill again for a second ball milling and drying to obtain the Ba-V-Cu oxide sintering aid; The preparation method of the BiVO4 oxide sintering aid comprises: adding Bi2O3 and V2O5 into a ball mill at a molar ratio of 1:1, performing a first ball milling mixing, and drying to obtain a mixture; then calcining the mixture at 500-750° C., and then putting the mixture into the ball mill again for a second ball milling and drying to obtain the BiVO4 oxide sintering aid.

8. A Ba5Nb4O 15 A low temperature co-fired ceramic substrate, characterized in that: The Ba5Nb4O 15 The low temperature co-fired ceramic substrate comprises the Ba5Nb4O 15 Based low temperature co-fired ceramic material.

9. A Ba5Nb4O 15 A method for preparing a low temperature co-fired ceramic substrate, characterized in that: The preparation method comprises the following steps: S1. Provide Ba5Nb4O as described in any one of claims 1 to 7. 15 Based on low temperature co-fired ceramic material, weigh the Ba5Nb4O 15 Ceramic powder, glass powder and oxide sintering aid are added to a ball mill and mixed for 1 to 4 hours. After drying, they are sieved with a 60 to 80 mesh screen to obtain Ba5Nb4O 15 Based low temperature co-fired ceramic materials; S2, in the Ba5Nb4O 15 The dispersant and the organic solvent are added to the low temperature co-fired ceramic for the first ball milling, and then the plasticizer, the binder and the leveling agent are added for the second ball milling to obtain the casting slurry, and the casting is formed into Ba5Nb4O 15 Base LTCC raw tape; S3, the Ba5Nb4O 15 The raw LTCC tape is laminated and isostatically pressed to form a green blank, and the green blank is sintered at 850°C to 900°C to prepare Ba5Nb4O 15 Based on low temperature co-fired ceramic substrate.

10. Ba5Nb4O according to claim 9 15 A method for preparing a low temperature co-fired ceramic substrate, characterized in that: The prepared Ba5Nb4O 15 The Ba5Nb4O 15 The dielectric constant of the low-temperature co-fired ceramic substrate is 39 to 42, the Q*f value is 12000 to 25000 GHz, and the resonant frequency temperature coefficient is -10 to 30 ppm / °C.

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