An LTCC raw material tape, an LTCC substrate, and a preparation method thereof.

Abstract

This invention discloses an LTCC raw material tape, an LTCC substrate, and a preparation method thereof. The LTCC raw material tape is formed by casting LTCC casting slurry. By mass percentage, the LTCC casting slurry includes 40wt% to 50wt% inorganic material components and 50wt% to 60wt% organic material components. By mass percentage, the inorganic material includes: 10-60wt% of one or two of BSi glass and BSiAl glass; 0-15wt% of one or two of CaAlSi microcrystalline glass, CaBSi microcrystalline glass, and BaBAlSi microcrystalline glass; and 10-60wt% of at least two of Al2O3 ceramic, SiO2 ceramic, ZrO2 ceramic, cordierite ceramic, and quartz glass powder. The organic material includes a solvent, a dispersant, a binder, and a plasticizer, wherein the solvent is an alcohol-ketone mixed solvent. This invention achieves a tight bond between the LTCC raw material tape and the silver electrode paste through co-firing by adjusting the mass ratio of BSi glass, BSiAl glass, CaAlSi microcrystalline glass, CaBSi microcrystalline glass, BaBAlSi microcrystalline glass, Al2O3 ceramic, SiO2 ceramic, ZrO2 ceramic, cordierite ceramic, and quartz glass powder.

Description

Technical Field

[0001] This invention relates to the field of low-temperature co-fired ceramic materials and their preparation, and particularly to an LTCC raw material tape material, an LTCC substrate, and a preparation method thereof. Background Technology

[0002] Low-temperature co-fired ceramics (LTCC) technology is an ideal packaging technology for miniaturizing and scaling up electronic components. With the increasing prevalence of 5G technology, the requirements for miniaturization and integration of electronic components are becoming increasingly stringent, while the amount of information is growing daily, demanding higher data capacity and transmission speeds. Especially when the feature size of electronic components in large-scale integrated circuits is less than 0.1 micrometers, the extremely high component density significantly reduces the distance between wires, increasing resistance and energy consumption. Furthermore, it creates RC circuits, causing signal delays and crosstalk noise, among other drawbacks. These problems have long constrained the development of very large-scale integrated circuits. The relationship between component signal delay time and resistance / capacitance can be expressed by the formula:

[0003] τ=RC=2ρε(4L 2 / d 2 +L 2 / T 2 ) Formula 1

[0004] Where τ is the signal delay time, R is the resistance, C is the capacitance, ρ is the resistance of the conductor metal, ε is the dielectric constant of the insulating material between the conductors, d is the distance between the conductors, L is the length of the connection, and T is the thickness of the line. Equation 1 clearly describes the relationship between the circuit integration level and the RC delay phenomenon. As the circuit integration level increases, the distance d between the conductors will inevitably decrease, the conductor thickness T will decrease, and the length of the connection will continuously increase. The only way to reduce the RC delay of the material is to reduce the resistivity of the conductor and the dielectric constant of the insulating layer. Since the resistivity of the conductor is greatly related to the material, and the conductors of LTCC multilayer circuit boards are mostly gold / silver conductors with relatively fixed resistivity, the only option is to reduce the dielectric constant of the insulating layer substrate.

[0005] Therefore, low-temperature co-fired ceramic (LTCC) materials require lower dielectric constants when used as substrates to reduce signal delay. When used as chip inductors, they also require lower dielectric constants and dielectric losses to reduce capacitance and increase inductance, thus adapting to high-frequency applications. Currently, LTCC materials with low dielectric constants (<5) are mainly produced by importing powders from the United States and Japan, with domestic manufacturers casting them into films.

[0006] Many domestic manufacturers have also developed LTCC ceramic powder with a dielectric constant of <5 by combining B2O3-SiO2 glass with silicon oxide ceramic, alumina ceramic, cordierite ceramic, and quartz glass powder. However, in this method, the LTCC raw material tape cast with powder is co-fired with silver electrode paste, resulting in a large number of bubbles around the silver electrode. This leads to a large number of pores around the LTCC ceramic sheet bonded to the silver electrode, making the LTCC substrate material unsuitable for commercial use. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing an LTCC raw material tape, an LTCC substrate, and a preparation method thereof.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] The first aspect of the present invention is to provide an LTCC raw material tape material, wherein the LTCC raw material tape is formed by casting LTCC casting slurry, and the LTCC casting slurry comprises 40wt% to 50wt% inorganic material components and 50wt% to 60wt% organic material components by mass percentage.

[0010] The inorganic materials, by mass percentage, include: 10-60 wt% of one or two of BSi glass and BSiAl glass; 0-15 wt% of one or two of CaAlSi microcrystalline glass, CaBSi microcrystalline glass, and BaBAlSi microcrystalline glass; and 10-60 wt% of at least two of Al2O3 ceramics, SiO2 ceramics, ZrO2 ceramics, cordierite ceramics, and quartz glass powder.

[0011] The organic materials include solvents, dispersants, binders, and plasticizers.

[0012] Furthermore, the content of each organic material component, calculated based on 100 parts of inorganic material, is the mass percentage of the inorganic material: solvent content is 90-125 wt%, dispersant content is 0.5-3 wt%, binder content is 7-15 wt%, and plasticizer content is 3-6 wt%.

[0013] Furthermore, the solvent is a mixture of methyl ethyl ketone (MEK) and isopropanol; the binder is polyvinyl butyral (PVB) or polymethyl methacrylate; the dispersant is castor oil or fish oil; and the plasticizer is one or two of dioctyl phthalate, polyethylene glycol, and dibutyl phthalate.

[0014] Further, based on the mass percentage of the BSi glass, the BSi glass comprises: 25-35% B2O3, 60-75% SiO2, 1-3wt% Na2O, and 1-3wt% K2O.

[0015] Further, based on the mass percentage of the BSiAl glass, the BSiAl glass comprises: 25-35% B2O3, 20-50% SiO2, 20-50 wt% Al2O3, 1-3 wt% Na2O, and 1-3 wt% K2O.

[0016] Further, based on the mass percentage of the CaAlSi microcrystalline glass, the CaAlSi microcrystalline glass comprises: CaO 20-50 wt%, Al2O3 15-40 wt%, SiO2 25-50 wt%, and B2O3 8-20 wt%.

[0017] Further, based on the mass percentage of the CaBSi microcrystalline glass, the CaBSi microcrystalline glass comprises: CaO 25-50wt%, B2O3 25-40wt%, SiO2 30-50wt%, and ZrO 2 1-3wt%.

[0018] Further, based on the mass percentage of the BaBAlSi microcrystalline glass, the BaBAlSi microcrystalline glass comprises: BaO 20-40 wt%, B2O3 20-30 wt%, Al2O3 10-20 wt%, and SiO2 30-50 wt%.

[0019] A second aspect of the present invention is to provide a method for preparing the above-mentioned LTCC raw material tape, comprising the following steps:

[0020] Step 1: Prepare BSi glass powder, BSiAl glass powder, CaAlSi microcrystalline glass powder, CaBSi microcrystalline glass powder, and BaBAlSi microcrystalline glass powder respectively: Weigh and mix the raw materials according to the ratio, melt them into glass liquid, quench them into glass blocks, and use anhydrous ethanol as the ball milling medium to control the D50 particle size of the powder to be 1.0-2.0 μm.

[0021] Step 2: Al2O3 ceramic powder, SiO2 ceramic powder, ZrO2 ceramic powder, cordierite ceramic powder, and quartz glass powder are respectively processed through a sand mill with water as the medium to control the D50 particle size of the powder to be 0.8-1.5μm.

[0022] Step 3: According to the formula, add the powder with controlled particle size into the ball mill jar, then add solvent and dispersant, and ball mill and mix. After the mixture is uniform, add plasticizer and binder, and ball mill and mix again. After vacuum degassing, cast and mold to obtain the LTCC raw material tape material.

[0023] Furthermore, the milling jar is filled with zirconium oxide balls.

[0024] A third aspect of the present invention is to provide an LTCC substrate, comprising the aforementioned LTCC raw material tape; the LTCC substrate, under 5 GHz conditions, has a dielectric constant that varies between 4.3 and 5.2, and a dielectric loss that fluctuates between 0.0025 and 0.0045; a bending strength of over 120 MPa; and is tightly bonded to the silver electrode paste by co-firing, with no bubbles on the silver surface.

[0025] A fourth aspect of the present invention is to provide a method for preparing the above-mentioned LTCC substrate, comprising the following steps:

[0026] The above-mentioned LTCC raw material tape is cut into the required size, stacked in multiple layers, and formed into a blank by vacuuming and isostatic pressing. The blank is placed in a sintering furnace and heated from room temperature to 450°C at a heating rate of 1°C / min, and held at that temperature for 3 hours to remove the adhesive. After the adhesive removal is completed, the temperature is raised to 850-900°C at a heating rate of 5°C / min and held at that temperature for 30 minutes to prepare the LTCC substrate.

[0027] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0028] In this invention, by adjusting the mass ratio of BSi glass, BSiAl glass, CaAlSi microcrystalline glass, CaBSi microcrystalline glass, BaBAlSi microcrystalline glass, Al2O3 ceramic, SiO2 ceramic, ZrO2 ceramic, cordierite ceramic, and quartz glass powder, a dense sintering process at 850-900℃ is ensured. This results in a dielectric constant of 4.3-5.2, a dielectric loss of 0.0025-0.0045, and a flexural strength exceeding 120 MPa for the prepared LTCC substrate material. More importantly, the LTCC raw material tape formed by casting is tightly bonded to the silver electrode paste during co-firing, resulting in no bubbles or pores around the silver electrode. Attached Figure Description

[0029] Figure 1 This is a DSC diagram of the BSi glass in an embodiment of the present invention.

[0030] Figure 2 This is a DSC diagram of the BSiAl glass in an embodiment of the present invention.

[0031] Figure 3 This is a DSC diagram of the CaAlSi microcrystalline glass in an embodiment of the present invention.

[0032] Figure 4 This is a DSC diagram of the CaBSi microcrystalline glass in an embodiment of the present invention.

[0033] Figure 5 This is a DSC image of the BaBSiAl microcrystalline glass in an embodiment of the present invention.

[0034] Figure 6 This is a SEM image (3000x magnification) of the cross-section of the LTCC substrate in Embodiment 7 of the present invention.

[0035] Figure 7 This is a SEM image (1200x magnification) of the cross-section of the LTCC raw material tape and silver electrode paste co-fired substrate at 870°C in Example 7 of the present invention.

[0036] Figure 8 This is an optical microscope image of the silver surface co-fired with the LTCC substrate in Embodiment 7 of the present invention. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0038] This invention provides an LTCC raw material tape material, which is formed by casting LTCC casting slurry. By mass percentage, the LTCC casting slurry includes 40wt% to 50wt% inorganic material components and 50wt% to 60wt% organic material components.

[0039] Based on the mass percentage of inorganic materials, the inorganic materials include: 10-60% wt% of one or two of BSi glass and BSiAl glass; 0-15 wt% of one or two of CaAlSi microcrystalline glass, CaBSi microcrystalline glass, and BaBAlSi microcrystalline glass; and 10-60 wt% of at least two of Al2O3 ceramics, SiO2 ceramics, ZrO2 ceramics, cordierite ceramics, and quartz glass powder.

[0040] Organic materials include solvents, dispersants, binders, and plasticizers.

[0041] Preferably, the content of each organic material component, calculated based on 100 parts of inorganic material, is the following percentage by mass of the inorganic material: solvent content is 90-125 wt%, dispersant content is 0.5-3 wt%, binder content is 7-15 wt%, and plasticizer content is 3-6 wt%.

[0042] More preferably, the solvent is a mixture of methyl ethyl ketone (MEK) and isopropanol; the binder is polyvinyl butyral (PVB) or polymethyl methacrylate; the dispersant is castor oil or fish oil; and the plasticizer is one or two of dioctyl phthalate, polyethylene glycol, and dibutyl phthalate.

[0043] The BSi glass comprises, by weight percentage: 25-35% B2O3, 60-75% SiO2, 1-3 wt% Na2O, and 1-3 wt% K2O. Optionally, B2O3 is introduced from boric acid, SiO2 from silica powder, Na2O from sodium carbonate, and K2O from potassium carbonate.

[0044] Boric acid, silica powder, sodium carbonate, and potassium carbonate are weighed and mixed according to the specified ratio. Preferably, the mixture is melted at 1500–1600℃ for 2–4 hours, quenched into glass blocks, and then sand-milled to control the particle size D50 to 1.0–2.0 μm. After drying, the powder is passed through a 40-mesh sieve to obtain BSi glass powder.

[0045] Based on the mass percentage of the BSiAl glass, the aforementioned BSiAl glass comprises: 25-35% B2O3, 20-50% SiO2, 20-50 wt% Al2O3, 1-3 wt% Na2O, and 1-3 wt% K2O. Optionally, B2O3 is introduced from boric acid, SiO2 from silica powder, Na2O from sodium carbonate, and K2O from potassium carbonate.

[0046] Boric acid, silica powder, alumina, sodium carbonate, and potassium carbonate are weighed and mixed according to a specified ratio. Preferably, the mixture is melted at 1500–1600℃ for 2–4 hours, quenched into glass blocks, and then sand-milled to control the particle size D50 to be 1.0–2.0 μm. After drying, the powder is passed through a 40-mesh sieve to obtain BSiAl glass powder.

[0047] Based on the mass percentage of the CaAlSi glass-ceramic, the aforementioned CaAlSi glass-ceramic comprises: CaO 20–50 wt%, Al2O3 15–40 wt%, SiO2 25–50 wt%, and B2O3 8–20 wt%. Optionally, CaO is introduced from calcium carbonate, B2O3 from boric acid, and SiO2 from silicon micropowder.

[0048] Calcium carbonate, boric acid, silica powder, and alumina are weighed and mixed according to a specified ratio. Preferably, the mixture is melted at 1400–1500℃ for 2–4 hours, quenched into glass blocks, and then sand-milled to control the particle size D50 to be 1.0–2.0 μm. After drying, the powder is passed through a 40-mesh sieve to obtain CaAlSi glass powder.

[0049] The CaBSi glass-ceramic comprises, by weight percentage: 25-50 wt% CaO, 25-40 wt% B2O3, 30-50 wt% SiO2, and 1-3 wt% ZrO2. Optionally, CaO is introduced from calcium carbonate, B2O3 from boric acid, and SiO2 from silica powder.

[0050] Calcium carbonate, boric acid, silica powder, and zirconium oxide are weighed and mixed according to a specified ratio. Preferably, the mixture is melted at 1400–1500℃ for 2–4 hours, quenched into glass blocks, and then sand-milled to control the particle size D50 to be 1.0–2.0 μm. After drying, the powder is passed through a 40-mesh sieve to obtain CaBSi glass powder.

[0051] The BaBAlSi microcrystalline glass comprises, by mass percentage: 20-40 wt% BaO, 20-30 wt% B2O3, 10-20 wt% Al2O3, and 30-50 wt% SiO2. Optionally, BaO is introduced from barium carbonate, B2O3 from boric acid, and SiO2 from silicon micropowder.

[0052] Barium carbonate, boric acid, silica powder, and alumina are weighed and mixed according to a specified ratio. Preferably, the mixture is melted at 1500–1600℃ for 2–4 hours, quenched into glass blocks, and then sand-milled to control the particle size D50 to be 1.0–2.0 μm. After drying, the powder is passed through a 40-mesh sieve to obtain BaBAlSi glass powder.

[0053] Al2O3 ceramic powder, SiO2 ceramic powder, ZrO2 ceramic powder, cordierite ceramic powder, and quartz glass powder are processed through a sand mill with water as the medium to control the D50 particle size of the powder to be 0.8-1.5 μm. After drying, the powder is passed through a 40-mesh sieve to obtain fine Al2O3 ceramic powder, fine SiO2 ceramic powder, fine ZrO2 ceramic powder, fine cordierite ceramic powder, and fine quartz glass powder.

[0054] Because BSi glass powder is a non-crystalline glass powder, and it begins to vitrify and melt at 700℃, while the cylindrical blank of BSi glass powder has already melted and collapsed at 850℃, it is more likely to react when sintered with silver electrode paste at 850-900℃. Therefore, after printing the silver electrode paste onto LTCC raw material tape and sintering, bubbling and pores are likely to appear on the ceramic sheet around the silver electrode.

[0055] While BSiAl glass is also a non-crystalline glass, it contains Al, which, like the silicon-oxygen network, allows it to form aluminum-oxygen tetrahedra or aluminum-oxygen octahedra. The aluminum-oxygen octahedra occupy more oxygen, causing the boron-oxygen trigonal [BO3] to transform into a boron-oxygen tetrahedron [BO4], resulting in a denser glass structure and a higher melting temperature of the glass powder. Therefore, when sintered with silver electrode paste at 850-900℃, blistering is less likely to occur around the silver electrode.

[0056] When CaAlSi, CaBSi, and BaBAlSi microcrystalline glass are ground into powder and then sintered at a higher temperature, they readily form CaSiO3, CaB2O4, and BaAl2Si2O8 crystal phases, respectively. These three crystal phases can make the glass structure more compact, making the cylindrical glass powder blank less prone to melting and collapse at 850-900℃, thus effectively preventing the silver electrode paste from reacting and bubbling due to the glass powder.

[0057] The present invention also provides a method for preparing the above-mentioned LTCC raw material tape: According to the ratio, the powder with controlled particle size is put into a nylon can containing zirconia balls, then solvent and dispersant are added, and ball milling is performed for 2-4 hours. After the mixture is uniform, plasticizer and binder are added to make the casting slurry have adhesiveness and toughness. Then ball milling is performed for 2-4 hours. After vacuum degassing, casting is performed to obtain the LTCC raw material tape material.

[0058] This invention also provides a method for preparing an LTCC substrate:

[0059] The raw material tape was cut into 100mm*100mm dimensions, 10 layers were cross-stacked, vacuum-sealed, and isostatically pressed into a green blank. The green blank was then placed in a sintering furnace and heated to 450℃ at a rate of 1℃ / min from room temperature. It was held at 450℃ for 3 hours to remove the binder. After binder removal, the temperature was increased to 850-900℃ at a rate of 5℃ / min and held for 30 minutes to complete sintering into a ceramic substrate. The dielectric constant and dielectric loss of the substrate were measured at 5GHz. Three samples were taken for each formulation, and the average value was used as the final test data.

[0060] The raw material tape is cut to the required size, and then 30-40 layers are cross-laminated, vacuumed, and isostatically pressed into a blank. The blank is then cut into strips with a height of 5mm, a width of 5mm, and a length of 45mm. The strips are then placed in a sintering furnace and heated to 450℃ at a rate of 1℃ / min from room temperature. The temperature is held at 450℃ for 3 hours to remove the binder. After the binder is removed, the temperature is increased to 850-900℃ at a rate of 5℃ / min and held for 30 minutes to obtain ceramic strips. The flexural strength of the ceramic strips is tested using a universal testing machine according to the method in GB / T 6569-2006.

[0061] Example

[0062] The formulations of BSi glass, BSiAl glass, CaAlSi microcrystalline glass, CaBSi microcrystalline glass, and BaBAlSi microcrystalline glass are shown in Table 1-5 below:

[0063] Table 1

[0064] Glass Number <![CDATA[B2O3(wt%)]]> <![CDATA[SiO2(wt%)]]> <![CDATA[Na2O(wt%)]]> <![CDATA[K2O(wt%)]]> BSi 27.5 70 1.5 1.0

[0065] Table 2

[0066] Glass Number <![CDATA[B2O3(wt%)]]> <![CDATA[SiO2(wt%)]]> <![CDATA[Al2O3(wt%)]]> <![CDATA[Na2O(wt%)]]> <![CDATA[K2O(wt%)]]> BSiAl 27.5 40 30 1.5 1.0

[0067] Table 3

[0068] Glass Number (CaOwt%) <![CDATA[Al2O3(wt%)]]> <![CDATA[SiO2(wt%)]]> <![CDATA[B2O3(wt%)]]> CaAlSi 22 30 30 18

[0069] Table 4

[0070] Glass Number (CaOwt%) <![CDATA[B2O3(wt%)]]> <![CDATA[SiO2(wt%)]]> <![CDATA[ZrO2(wt%)]]> CaBSi 30 27 41.5 1.5

[0071] Table 5

[0072] Glass Number BaO (wt%) <![CDATA[B2O3(wt%)]]> <![CDATA[Al2O3(wt%)]]> <![CDATA[SiO2(wt%)]]> BaBSiAl 25 22 15 38

[0073] The proportions of inorganic materials in LTCC raw material tape are shown in Table 6 below (i.e., Examples 1-11):

[0074] Table 6

[0075]

[0076] The proportions of organic materials in LTCC casting slurry are shown in Table 7 below (i.e., Examples 1-11):

[0077] Table 7

[0078]

[0079] In this invention, the organic material only serves as a carrier. During the 450℃ debinding process, all the organic material reacts and volatilizes, while the inorganic materials (glass, ceramics) remain unchanged. Between 450℃ and 900℃, the reaction primarily occurs between the glass and ceramics. After this process, the substrate is sintered into an LTCC substrate. The casting pastes in Examples 1-11 above contain 50-60 wt% organic material. By adjusting the ratio of organic material in the casting paste, LTCC raw tapes with a smooth appearance, no cracks, and good toughness can be prepared.

[0080] The dielectric constant, dielectric loss, flexural strength, and porosity around silver of the LTCC raw tapes prepared in Examples 1-11 after sintering at 850-900℃ for 30 min are shown in Table 8 below.

[0081] Table 8

[0082]

[0083] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the content and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. An LTCC raw material tape material, wherein the LTCC raw material tape is formed by casting LTCC casting slurry, characterized in that, The LTCC casting slurry comprises 40wt% to 50wt% inorganic material components and 50wt% to 60wt% organic material components by weight percentage. The inorganic materials, by mass percentage, comprise: 10-60 wt% BSi glass and BSiAl glass; 5-15 wt% one or two of CaAlSi microcrystalline glass, CaBSi microcrystalline glass, and BaBAlSi microcrystalline glass; 10-60 wt% at least two of Al2O3 ceramics, SiO2 ceramics, ZrO2 ceramics, cordierite ceramics, and quartz glass powder; totaling 100 wt%. The BSi glass comprises, by weight percentage: 25-35% B2O3, 60-75% SiO2, 1-3wt% Na2O, and 1-3wt% K2O; totaling 100wt%. The BSiAl glass comprises, by weight percentage: 25-35% B2O3, 20-50% SiO2, 20-50 wt% Al2O3, 1-3 wt% Na2O, and 1-3 wt% K2O. Based on the mass percentage of the CaAlSi microcrystalline glass, the CaAlSi microcrystalline glass comprises: CaO 20~50wt%, Al2O3 15~40wt%, SiO2 25~50wt%, and B2O3 8~20wt%; Based on the mass percentage of the CaBSi glass-ceramic, the CaBSi glass-ceramic comprises: CaO 25~50wt%, B2O3 25~40wt%, SiO2 30~50wt%, and ZrO2 1~3wt%. Based on the mass percentage of the BaBAlSi microcrystalline glass, the BaBAlSi microcrystalline glass comprises: BaO 20~40wt%, B2O3 20~30wt%, Al2O3 10~20wt%, and SiO2 30~50wt%; The organic materials include solvents, dispersants, binders, and plasticizers.

2. The LTCC raw material tape material according to claim 1, characterized in that, The content of each organic material component, calculated based on 100 parts of inorganic material, is a percentage of the mass of the inorganic material: solvent content is 90~125wt%, dispersant content is 0.5~3wt%, binder content is 7~15wt%, and plasticizer content is 3~6wt%. The solvent is a mixture of methyl ethyl ketone (MEK) and isopropanol; the binder is polyvinyl butyral or polymethyl methacrylate; the dispersant is castor oil or fish oil; and the plasticizer is one or two of dioctyl phthalate, polyethylene glycol, and dibutyl phthalate.

3. A method for preparing LTCC raw material tape as described in any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Prepare BSi glass powder, BSiAl glass powder, CaAlSi microcrystalline glass powder, CaBSi microcrystalline glass powder, and BaBAlSi microcrystalline glass powder respectively: Weigh and mix the raw materials according to the ratio, melt them into glass liquid, quench them into glass blocks, and use anhydrous ethanol as the ball milling medium to control the D50 particle size of the powder to be 1.0~2.0μm. Step 2: Al2O3 ceramic powder, SiO2 ceramic powder, ZrO2 ceramic powder, cordierite ceramic powder, and quartz glass powder are respectively processed through a sand mill with water as the medium to control the D50 particle size of the powder to be 0.8~1.5μm. Step 3: According to the formula, add the powder with controlled particle size into the ball mill jar, then add solvent and dispersant, and ball mill and mix. After the mixture is uniform, add plasticizer and binder, and ball mill and mix again. After vacuum degassing, cast and mold to obtain the LTCC raw material tape material.

4. An LTCC substrate, characterized in that, The LTCC substrate comprises the LTCC raw material tape as described in any one of claims 1-2; the dielectric constant of the LTCC substrate varies between 4.3 and 5.2 under 5GHz conditions, and the dielectric loss fluctuates between 0.0025 and 0.0045; the bending strength is above 120MPa, and it is tightly bonded to the silver electrode paste by co-firing, with no bubbles on the silver surface.

5. A method for fabricating an LTCC substrate, characterized in that, Includes the following steps: LTCC raw material tape prepared by the preparation method described in claim 4; The LTCC raw material tape is cut to the required size, stacked in multiple layers, and formed into a blank by vacuuming and isostatic pressing. The blank is placed in a sintering furnace and heated from room temperature to 450°C at a heating rate of 1°C / min, and held for 3 hours to remove the adhesive. After the adhesive is removed, the temperature is raised to 850-900°C at a heating rate of 5°C / min and held for 30 minutes to prepare the LTCC substrate.

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