CN113683405A - Low-temperature co-fired nano ceramic material, green ceramic tape and preparation method - Google Patents

Abstract

An LTCC material suitable for mobile phone radio frequency consists of ceramic powder and a sintering aid, and realizes sintering densification below 950 ℃; the ceramic powder of the LTCC material is formed by compounding two kinds of powder with high dielectric property, and has a specific chemical composition of (1)‑x)Zn₂SiO₄And xCaTiO₃Wherein x is 0.02-0.98; the main body of the sintering aid is CuO and B₂O₃、V₂O₅、Bi₂O₃One or a mixture of two or more of them. The green tape material consists of an LTCC material, a solvent, a dispersant, a binder, a defoaming agent and a plasticizer material, and is obtained after uniform mixing, salivation and drying; the green tape is composed of an LTCC material, a solvent, a dispersant, a binder and a plasticizer.

Description

Low-temperature co-fired nano ceramic material, green ceramic tape and preparation method

Technical Field

The invention belongs to the field of low-temperature co-fired ceramic materials, and particularly relates to a high-performance low-temperature co-fired nano ceramic material (nm-LTCC) and a green ceramic tape suitable for mobile phone radio frequency or other high-frequency band applications and a preparation method thereof, which are used for preparing related electronic devices.

Background

LTCC technology, which is a highly interesting integrated component technology developed in recent years, has become the mainstream technology of passive integration, and relates to low temperature co-fired materials and low temperature co-fired processes, wherein low temperature co-fired ceramic materials are the most critical and fundamental problems.

LTCC is a ceramic tape with precise and compact thickness made of low-temperature sintered ceramic powder, and the required circuit pattern is made on the ceramic tape by using the processes of laser drilling, micropore grouting, printing with precise conductor paste, etc., and a plurality of passive components (such as low-capacitance value capacitor, resistor, filter, impedance converter, coupler, etc.) are embedded into a multilayer ceramic substrate, and then laminated together, and the internal and external electrodes can be sintered at the temperature of about 900 ℃ by using metals such as silver, copper, gold, etc. to make a three-dimensional high-density circuit without mutual interference, or a three-dimensional circuit substrate with built-in passive elements, and an IC and an active device can be pasted on the surface of the three-dimensional high-density circuit substrate to make a passive/active integrated functional module, further miniaturizing and densifying the circuit, and is particularly suitable for high-frequency communication components. There are various methods for integrating a plurality of passive components of different types and different performances in one package, mainly including low temperature co-fired ceramic (LTCC) technology, thin film technology, multilayer circuit board technology, etc. LTC technology is the mainstream technology for passive integration. LTCC integrated components include various products with various active or passive components carried on or embedded in substrates, and the integrated component products include components (components), substrates (substructures), and modules (modules).

At present, commercial LTCC green tape produced by foreign enterprises is limited in variety, the dielectric constant epsilon of the material is between 5 and 10, the LTCC green tape is mainly used for packaging multilayer substrates, chip inductors, Bluetooth modules, integrated circuits and the like, and the diversified requirements of products cannot be met. Large component manufacturers, such as village field and solar induced power, independently research and develop corresponding material systems aiming at products.

The problem faced by domestic LTCC industry is mainly that of raw materials, and most of LTCC dielectric materials adopt imported raw materials at present, so that the research and development of middle-high-end products are delayed. At present, the serialized ceramic powder for LTCC with best independent intellectual property rights needs to be developed in China, and the serialized ceramic green tape for LTCC is produced professionally, so that the foundation is laid for the development of LTCC devices.

The Chinese patent application CN 110790568A provides a low-dielectric LTCC green tape and a preparation method and application thereof, and the main technical implementation scheme is as follows: firstly, Zn is adopted in a Zn vacancy mode according to the chemical composition of a ceramic material_2-xSiO_4-xWeighing ZnO and SiO₂As initial powder, mixing the initial powder, ball milling, drying, calcining, ball milling and refining to prepare Zn without impurity phase_2-xSiO_4-xPure phase; secondly, weighing CaCO according to the proportion₃、SiO₂、H₃BO₃、Al₂O₃、P₂O₅、Na₂CO₃、Li₂CO₃After mixing evenly, melting, quenching, ball milling and drying to prepare the sintering aid calcium borosilicate glass, and Zn is realized by adjusting the formula of the calcium borosilicate glass_{2- x}SiO_4-xSintering at 850 ℃; thirdly, Zn is mixed according to the mixture ratio_2-xSiO_4-xThe ceramic material, the sintering aid calcium borosilicate glass, the low-melting-point oxide, the solvent, the plasticizer, the dispersant and the binder are subjected to ball milling, mixing and defoaming to prepare casting slurry with the solid content of 45 wt% -65 wt%, and then the casting slurry is prepared into the raw porcelain band through casting equipment.

The patent application also provides a low-dielectric LTCC green tape and a preparation method and application thereof. But has the following disadvantages: electronic ceramics generally want to maintain a single phase of the material after sintering, while the patent application uses ceramic + glass ceramics as the main body of the ceramic powder, during sintering, the calcium-boron-silicon glass ceramics can separate out at least one crystal phase and is uncontrollable, and the electrical property of the ceramic can be seriously deteriorated; secondly, the prior art uses various substances harmful to human bodies, such as toluene, butanone and the like, when preparing the casting slurry; the third disadvantage is that the concerned performance indexes of the LTCC green tape prepared by the patent application only have dielectric constant and dielectric loss, and compared with one surface, other more critical performances such as thermal conductivity, breakdown voltage resistance, strength, TCE and the like are not reflected at all, so that great uncertainty exists for the actual LTCC design; and the performance indexes of the raw materials used in the prior art have no more visual data, and the key factors influencing the quality of the LTCC green tape are the type, content (purity), granularity and morphology of the ceramic powder.

The invention content is as follows:

the invention aims to provide a high-performance LTCC material suitable for mobile phone radio frequency and a preparation method of a green ceramic tape, aiming at solving the problems related to the type, content, granularity, morphology, environmental protection property of casting slurry and the like of ceramic powder in the preparation process of the traditional LTCC green ceramic tape and the performance index clarification of the green ceramic tape in the actual LTCC device design.

In order to achieve the above object, the present invention provides the following technical solutions: a high-performance LTCC material suitable for mobile phone radio frequency and a raw ceramic tape prepared by matching the LTCC material with other materials, wherein the LTCC material consists of ceramic powder and a sintering aid and realizes sintering compactness below 950 ℃; the green tape is composed of LTCC material, solvent, dispersant, binder, defoamer and plasticizer. The ceramic powder of the LTCC material is formed by compounding two kinds of powder with high dielectric property, and the specific chemical composition is (1-x) Zn₂SiO₄And xCaTiO₃Wherein x is 0.02-0.98; the main body of the sintering aid is CuO and B₂O₃、V₂O₅、Bi₂O₃One or a mixture of two or more of them. The main body of the sintering aid is CuO and B₂O₃、V₂O₅、Bi₂O₃One of them is orMixtures of the two or more.

Single-phase Zn in the composite ceramic powder₂SiO₄、CaTiO₃The ceramic powder is prepared by a sol-gel method respectively, so that the particle size of the ceramic powder reaches the nanometer level;

preparation of Zn by sol-gel method₂SiO₄Powder, Zn (NO) as the raw material₃)₂·5H₂O, absolute ethyl alcohol, ethyl orthosilicate and PEG400, wherein the purity of the materials is analytically pure, the raw materials are weighed according to the Zn/Si molar ratio of 2:1, and Zn (NO) is added₃)₂·5H₂Dissolving O and ethyl orthosilicate in absolute ethyl alcohol respectively, dissolving and stirring for more than 30min respectively, then mixing the two solutions, adding a dispersing agent PEG400, stirring and mixing uniformly, standing for more than 1 hour, forming gel after 60-80 hours, finally drying at 80-100 ℃ (20 +/-10 hours) to form dry glue, putting the dry glue into a muffle furnace, keeping the temperature at 600-1000 ℃ for 1-4 hours to form Zn with the nanometer size of about 80 nm₂SiO₄And (3) powder.

Single-phase Zn in the composite ceramic powder₂SiO₄、CaTiO₃The ceramic powder is prepared by a sol-gel method respectively, so that the particle size of the ceramic powder particles reaches about 80 +/-40 nanometers;

sol-gel method for preparing nano CaTiO₃The powder comprises the required raw materials of butyl titanate, absolute ethyl alcohol, concentrated nitric acid (the mass fraction is 65-70%), and Ca (NO)₃)₂·4H₂O, PEG1000, purity is analytical purity, raw materials are weighed according to the molar ratio of Ca to Ti of 1:1, and weighed butyl titanate and Ca (NO) are respectively weighed₃)₂·4H₂Dissolving O in absolute ethyl alcohol to form a solution, dissolving and stirring for more than 30min, then mixing the two solutions, adding a dispersing agent PEG1000, simultaneously adding concentrated nitric acid (particularly with the mass fraction of 65-70%) to adjust the pH to about 4, stirring and mixing uniformly, standing for more than 1 hour (1-4), forming gel after 60-80 hours, finally drying at 80-100 ℃ (20 hours) to form dry glue, putting the dry glue into a muffle furnace, keeping the temperature for 1-4 hours at 600 ℃ for 1000 ℃ to form CaTiO of about 80 +/-40 nanometers₃And (3) powder.

The preparation of the LTCC material suitable for the radio frequency of the mobile phoneThe method comprises sintering at low temperature by liquid phase coating method and solid phase mixing method, adding sintering aid, wherein CuO is directly coated on ceramic powder by liquid phase coating method, and CuSO is selected as raw material of the sintering aid₄·5H₂O is used as a raw material, CuSO4 solution with the concentration of 0.5-1.5 mol/L is prepared, ceramic powder is added while stirring, and the drying temperature is 120 +/-20 ℃ (10-20h), so that coating is achieved; the rest B₂O₃、V₂O₅、Bi₂O₃One or two or more sintering aids are introduced into the composite ceramic powder through ball milling and solid phase mixing, so that the sintering at the low temperature of 950 ℃ is carried out at 800-.

The green tape material consists of an LTCC material, a solvent, a dispersant, a binder, a defoaming agent and a plasticizer material, and is obtained after uniform mixing, salivation and drying; the green tape is composed of an LTCC material, a solvent, a dispersant, a binder and a plasticizer, wherein the LTCC material accounts for 45-70 parts by mass, and the rest solvent, the dispersant, the binder, the plasticizer and a defoaming agent account for 30-55 parts by mass.

The solvent for the green porcelain tape is a mixture of butyl alcohol, trichloroethylene and methanol.

The dispersing agent is a mixture of herring oil and tributyl phosphate, the binder is polyvinyl butyral, the plasticizer is a mixture of polyethylene glycol and octyl phthalic acid, and the defoaming agent is tributyl phosphate.

The residual solvent, the dispersant, the binder, the plasticizer and the defoaming agent comprise the following components in parts by mass: 25-30 parts of solvent, 18-25 parts of binder, 1.7-3.5 parts of plasticizer, 0.85-3.25 parts of dispersant and 0.35-0.5 part of defoaming agent.

The thickness of the green ceramic tape is 100-300 mu m.

The preparation method of the green porcelain tape comprises the following steps:

preparation of LTCC material: zn according to the chemical composition (1-x) of the composite ceramic powder₂SiO₄-xCaTiO₃Weighing raw materials, and preparing Zn by sol-gel method₂SiO₄、CaTiO₃Mixing the two powders at a certain proportion, coating CuO on the surface of the composite powder by liquid phase coating method, and ball millingAdding other low-temperature oxide sintering aids, and drying to obtain the LTCC material;

preparing raw porcelain tape slurry: ball-milling, mixing and defoaming the LTCC material, the solvent, the plasticizer, the dispersant, the binder and the defoamer according to the proportion to prepare casting slurry with the solid content of 45-70 percent;

carrying out tape casting on the green ceramic tape to prepare an LTCC green ceramic tape; in the preparation process of the green tape slurry, the binder is a pre-mixed colloidal solution, the solvent of the colloidal solution is the same as that of the green tape slurry, and the mass fraction of the binder in the colloidal solution is 25 +/-5%.

Has the advantages that: the performance indexes of the green porcelain tape prepared by the method are shown in the table, wherein the performance of the green porcelain tape is basically consistent with that of products of DuPont company in America, and the performance indexes are shown in the attached tables 1 and 2. Through multidimensional tests and tests of a project team, the green porcelain tape prepared by the method has good stability and excellent performance indexes.

Attached table 1

Attached table 2

Drawings

FIG. 1 is a flow chart of the low-temperature nano-ceramic co-firing technology of the present invention.

Detailed Description

Example 1: the preparation method of the green porcelain tape comprises the following steps:

preparation of LTCC material: according to the chemical composition of the composite ceramic powder, 0.5Zn₂SiO₄-0.5CaTiO₃Weighing raw materials, and preparing Zn by sol-gel method₂SiO₄、CaTiO₃Powder, the two are compounded according to molar ratio, and CuO is coated on the surface of the composite powder by a liquid phase coating method, wherein a sintering aid CuO is adoptedThe ceramic powder is directly coated by a liquid phase coating method, and the raw material of the sintering aid is CuSO₄·5H₂O is taken as a raw material, CuSO4 solution with the concentration of 1.0mol/L is prepared, ceramic powder is added while stirring, and the drying temperature is 120 +/-20 ℃ (10-20h), so as to achieve coating; finally, other low-temperature oxides (such as B) are introduced by ball milling and mixing₂O₃、V₂O₅、Bi₂O₃One of the sintering aids), and the rest or two or more of the sintering aids are introduced into the composite ceramic powder through ball milling and solid phase mixing, so that the sintering is carried out for 6-10h at 880 ℃, and the low-temperature sintering at about 850 ℃ is generally better. Preparing an LTCC material;

preparing raw porcelain tape slurry: the LTCC material is prepared according to the mixture ratio, wherein the mass part of the LTCC material is 45-70 parts; solvent, plasticizer, dispersant, binder, defoamer (30-55 parts by mass of the residual solvent, the dispersant, the binder, the plasticizer and the defoamer) are ball-milled, mixed and defoamed to prepare casting slurry with solid content of 45-70%;

tape casting of the raw porcelain tape: casting on a LY-250-1 type casting machine to obtain the LTCC green ceramic tape;

in the preparation process of the LTCC material, alcohol is used as a ball milling medium in the ball milling process, and agate balls are used for ball milling for 2-4 hours.

In the preparation process of the green tape slurry, the binder is a pre-mixed colloidal solution, the solvent of the colloidal solution is the same as that of the green tape slurry, and the mass fraction of the binder in the colloidal solution is 25%.

Example 2:

single-phase Zn in the composite ceramic powder₂SiO₄、CaTiO₃The ceramic powder is prepared by a sol-gel method respectively, so that the particle size of the ceramic powder can reach the nanometer level or quasi-nanometer level, the uniformity is good, and the crystal structure is more compact.

Preparation of Zn by sol-gel method₂SiO₄Powder (all raw materials including an assistant and the like having a purity of 2N or more, preferably 3N or more), and Zn (NO) as a required raw material₃)₂·5H₂O, absolute ethyl alcohol, ethyl orthosilicate and PEG400The purity of the material is analytically pure, the raw material is weighed according to the Zn/Si molar ratio of 2:1, and Zn (NO) is added₃)₂·5H₂Dissolving O and tetraethoxysilane in absolute ethyl alcohol respectively, dissolving and stirring for 1 hour respectively, then mixing the two solutions, adding a dispersing agent PEG400, stirring and mixing uniformly, standing for 2 hours, forming gel after 60-80 hours, finally drying at 80-100 ℃ (20 hours) to form dry glue, putting the dry glue into a muffle furnace, keeping the temperature at 600-1000 ℃ for 1-4 hours, and forming the nanoscale or near-nanoscale Zn₂SiO₄And (3) powder.

Preparation of CaTiO by sol-gel method₃The powder comprises the required raw materials of butyl titanate, absolute ethyl alcohol, concentrated nitric acid (the mass fraction of the concentration is preferably 65-70 percent), and Ca (NO)₃)₂·4H₂O, PEG1000, purity is analytical purity, raw materials are weighed according to the molar ratio of Ca to Ti of 1:1, and weighed butyl titanate and Ca (NO) are respectively weighed₃)₂·4H₂Dissolving O in absolute ethyl alcohol to form a solution, dissolving and stirring for 1 hour, then mixing the two solutions, adding a dispersing agent PEG1000, simultaneously adding concentrated nitric acid to adjust the pH to about 4, uniformly stirring and mixing, standing for 2 hours, forming gel after 60-80 hours, finally drying at 80-100 ℃ (20 hours) to form dry glue, putting the dry glue into a muffle furnace, keeping the temperature at 600 ℃ for 1000 ℃ for 1-4 hours to form nano-scale or near-nano-scale CaTiO₃And (3) powder.

Example 3:

the sintering aid is introduced by the combined action of a liquid phase coating method and a solid phase mixing method, wherein CuO serving as the sintering aid is directly coated on ceramic powder by the liquid phase coating method, and CuSO is selected₄·5H₂O is used as a raw material, CuSO4 solution with the concentration of 0.5-1.5 mol/L is prepared, ceramic powder is added while stirring, and the drying temperature is 120 ℃ (12h), so that coating is achieved; the rest B₂O₃、V₂O₅、Bi₂O₃The sintering aid is introduced into the composite ceramic powder by ball milling and solid phase mixing, thereby achieving the purpose of low-temperature sintering.

The green tape is composed of an LTCC material, a solvent, a dispersant, a binder and a plasticizer, wherein the LTCC material accounts for 45-70 parts by mass, and the rest of the solvent, the dispersant, the binder, the plasticizer and the defoamer accounts for 30-55 parts by mass.

The solvent for the green porcelain tape is a mixture of butyl alcohol, trichloroethylene and methanol.

The dispersing agent is a mixture of herring oil and tributyl phosphate, the binder is polyvinyl butyral, the plasticizer is a mixture of polyethylene glycol and octyl phthalic acid, and the defoaming agent is tributyl phosphate.

The residual solvent, the dispersant, the binder, the plasticizer and the defoaming agent comprise the following components in parts by mass: 25-30 parts of solvent, 18-25 parts of binder, 1.7-3.5 parts of plasticizer, 0.85-3.25 parts of dispersant and 0.35-0.5 part of defoaming agent.

The thickness of the green ceramic tape is 100-300 mu m.

Example 4:

the method of making green tape, reference example 1, included the following steps: preparation of LTCC material: according to the chemical composition of the composite ceramic powder 0.3Zn₂SiO₄-0.7CaTiO₃Weighing raw materials, and preparing Zn by sol-gel method₂SiO₄、CaTiO₃And finally, introducing other low-temperature oxide sintering aids through ball milling and mixing, and drying to obtain the LTCC material.

Preparing raw porcelain tape slurry: and ball-milling, mixing and defoaming the LTCC material, the solvent, the plasticizer, the dispersant, the binder and the defoaming agent according to the proportion to prepare casting slurry with the solid content of 45-70%.

Tape casting of the raw porcelain tape: and casting on a LY-250-1 type casting machine to obtain the LTCC green ceramic tape.

In the preparation process of the LTCC material, alcohol is used as a ball milling medium in the ball milling process, and agate balls are used for ball milling for 2-4 hours. The properties of the green tapes obtained in examples 1 and 4 are those shown in the table.

0.05Zn₂SiO₄-0.95CaTiO₃Weighing raw materials, 0.95Zn₂SiO₄-0.05CaTiO₃Similar results were obtained by weighing the starting materials.

In the preparation process of the green tape slurry, the binder is a pre-mixed colloidal solution, the solvent of the colloidal solution is the same as that of the green tape slurry, and the mass fraction of the binder in the colloidal solution is 25%.

Claims (10)

1. An LTCC material suitable for mobile phone radio frequency is characterized in that the LTCC material is composed of ceramic powder and a sintering aid, and sintering densification below 950 ℃ is realized; the ceramic powder of the LTCC material is formed by compounding two kinds of powder with high dielectric property, and the specific chemical composition is (1-x) Zn₂SiO₄And xCaTiO₃Wherein x is 0.02-0.98; the main body of the sintering aid is CuO and B₂O₃、V₂O₅、Bi₂O₃One or a mixture of two or more of them.

2. The method for preparing the LTCC material suitable for the radio frequency of the mobile phone as claimed in claim 1, wherein the composite ceramic powder comprises single-phase Zn₂SiO₄、CaTiO₃The ceramic powder is prepared by a sol-gel method respectively, so that the particle size of the ceramic powder reaches the nanometer level or quasi-nanometer level;

preparation of Zn by sol-gel method₂SiO₄Powder, Zn (NO) as the raw material₃)₂·5H₂O, absolute ethyl alcohol, ethyl orthosilicate and PEG400, wherein the purity of the materials is analytically pure, the raw materials are weighed according to the Zn/Si molar ratio of 2:1, and Zn (NO) is added₃)₂·5H₂Dissolving O and ethyl orthosilicate in absolute ethyl alcohol respectively, dissolving and stirring for more than 30min respectively, then mixing the two solutions, adding a dispersing agent PEG400, stirring and mixing uniformly, standing for more than 1 hour, forming gel after 60-80 hours, finally drying at 80-100 ℃ (20 +/-10 hours) to form dry glue, putting the dry glue into a muffle furnace, keeping the temperature for 1-4 hours at 600-₂SiO₄And (3) powder.

3. The method for preparing the LTCC material suitable for the radio frequency of the mobile phone according to claim 1Characterized in that the composite ceramic powder contains single-phase Zn₂SiO₄、CaTiO₃The ceramic powder is prepared by a sol-gel method respectively, so that the particle size of the ceramic powder reaches the nanometer level or quasi-nanometer level;

preparation of CaTiO by sol-gel method₃The powder comprises the required raw materials of butyl titanate, absolute ethyl alcohol, concentrated nitric acid (the mass fraction is 65-70%), and Ca (NO)₃)₂·4H₂O, PEG1000, purity is analytical purity, raw materials are weighed according to the molar ratio of Ca to Ti of 1:1, and weighed butyl titanate and Ca (NO) are respectively weighed₃)₂·4H₂Dissolving O in absolute ethyl alcohol to form a solution, dissolving and stirring for more than 30min, then mixing the two solutions, adding a dispersing agent PEG1000, simultaneously adding concentrated nitric acid (particularly with the mass fraction of 65-70%) to adjust the pH to about 4, uniformly stirring and mixing, standing for more than 1 hour, forming gel after 60-80 hours, finally drying at 80-100 ℃ (20 hours) to form dry glue, putting the dry glue into a muffle furnace, keeping the temperature for 1-4 hours at the temperature of 600 ℃. times, and then forming nano-scale or near-nano-scale CaTiO₃And (3) powder.

4. The method for preparing an LTCC material suitable for mobile phone radio frequency as claimed in one of claims 1 to 3, wherein the LTCC material is prepared by a liquid phase coating method and a solid phase mixing method, the low temperature sintering is performed, a sintering aid is added, wherein the sintering aid CuO is directly coated on the ceramic powder by the liquid phase coating method, and CuSO is selected as the raw material of the sintering aid₄·5H₂O is used as a raw material, CuSO4 solution with the concentration of 0.5-1.5 mol/L is prepared, ceramic powder is added while stirring, and the drying temperature is 120 +/-20 ℃ (10-20h), so that coating is achieved; the rest B₂O₃、V₂O₅、Bi₂O₃One or two or more sintering aids are introduced into the composite ceramic powder through ball milling and solid phase mixing, so that the sintering at the low temperature of 950 ℃ is carried out at 800-.

5. A green tape made of LTCC materials suitable for mobile phone radio frequency according to one of claims 1 to 4, wherein the green tape material is composed of LTCC materials, solvent, dispersant, binder, defoamer and plasticizer materials, and is obtained after uniform mixing, salivation and drying;

the green tape is composed of an LTCC material, a solvent, a dispersant, a binder and a plasticizer, wherein the LTCC material accounts for 45-70 parts by mass, and the rest solvent, the dispersant, the binder, the plasticizer and a defoaming agent account for 30-55 parts by mass.

6. The green tape as claimed in claim 5, wherein the solvent for the green tape is a mixture of butyl alcohol, trichloroethylene and methanol.

7. The green tape as claimed in claim 5 or 6, wherein the dispersant is a mixture of menhaden oil and tributyl phosphate, the binder is polyvinyl butyral, the plasticizer is a mixture of polyethylene glycol and octyl phthalic acid, and the defoamer is tributyl phosphate.

8. The green tape according to claim 5 or 6, wherein the solvent, the dispersant, the binder, the plasticizer and the defoaming agent are, in parts by mass: 25-30 parts of solvent, 18-25 parts of binder, 1.7-3.5 parts of plasticizer, 0.85-3.25 parts of dispersant and 0.35-0.5 part of defoaming agent.

9. The green tape as claimed in claim 5 or 6, wherein the thickness of the green tape is 100-300 μm.

10. A method for preparing a green tape according to any one of claims 5 to 9, wherein the method for preparing a green tape comprises the steps of:

preparation of LTCC material: zn according to the chemical composition (1-x) of the composite ceramic powder₂SiO₄-xCaTiO₃Weighing raw materials, and preparing Zn by sol-gel method₂SiO₄、CaTiO₃Compounding the powder and the powder in proportion, coating CuO on the surface of the composite powder by a liquid phase coating method, introducing other low-temperature oxide sintering aids by ball milling and mixing, and drying to obtain the LTCC material;

preparing raw porcelain tape slurry: ball-milling, mixing and defoaming the LTCC material, the solvent, the plasticizer, the dispersant, the binder and the defoamer according to the proportion to prepare casting slurry with the solid content of 45-70 percent;

carrying out tape casting on the green ceramic tape to prepare an LTCC green ceramic tape; in the preparation process of the green tape slurry, the binder is a pre-mixed colloidal solution, the solvent of the colloidal solution is the same as that of the green tape slurry, and the mass fraction of the binder in the colloidal solution is 25 +/-5%.

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