A low-dielectric-low-loss LTCC material and its preparation method and green porcelain tape

Abstract

The present invention relates to a low-dielectric-low-loss LTCC material, a preparation method thereof, and a green ceramic tape. The low-dielectric-low-loss LTCC material is prepared by mixing a ceramic filling phase and a glass low-sintering aid, wherein the ceramic filling phase is a lanthanum borosilicate microwave dielectric ceramic LaBSiO5, and the glass low-sintering aid is La2O3-B2O3 glass. The low-dielectric-low-loss LTCC material of the present invention uses a lanthanum borosilicate microwave dielectric ceramic with low dielectric and low loss characteristics and a low sintering temperature (<1200°C) as the ceramic filling phase, and uses La2O3-B2O3 glass as the glass low-sintering aid. This reduces the loss of the ceramic-glass system and the sintering temperature of the low-dielectric-low-loss LTCC material, allowing the LaBSiO5 material to be sintered within a temperature range below 900°C and having excellent microwave dielectric properties. This allows the LTCC substrate material prepared using the LTCC green ceramic tape to have a low dielectric constant and dielectric loss.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a low-dielectric-low-loss LTCC material, a preparation method thereof, and a green ceramic tape. Background Art

[0002] With the continuous advancement of wireless communication equipment and microwave technology, microwave circuit components with their small size, lightweight, and multifunctionality are gaining increasing attention in the consumer electronics market. Low-temperature co-fired ceramic (LTCC) technology, developed in the 1980s, is a key enabler for the development of microwave components towards high-density integration, high reliability, and high frequency. LTCC technology employs three-dimensional circuit design and simultaneously fires electrode and dielectric materials according to the designed structure. It is a packaging technology used for high integration, lightweight, and high performance. LTCC technology has strict requirements for the sintering temperature of the material. To be able to co-fire with electrodes such as Ag (961°C), the sintering temperature must be below 950°C. Furthermore, to meet packaging requirements, LTCC materials must have a certain thermal conductivity, an appropriate thermal expansion coefficient, and high mechanical strength to meet the requirements of high-reliability packaging.

[0003] Typical commercial LTCC materials include the following two systems: (1) Microcrystalline glass materials, such as Ferro's A6M green tape, which is mainly made of Ca-B-Si microcrystalline glass. During the sintering process, the glass crystallizes into a low-loss phase, giving the material low dielectric loss. The loss of A6M green tape at 1-100GHz is less than 0.002, and the dielectric constant is 5.9, which meets the requirements of high-frequency microwave circuits. (2) Ceramic + glass materials, which add low-softening-point glass to the ceramic filler to reduce the sintering temperature of electronic ceramic materials. Ceramics such as Al2O3, mullite, and cordierite, and glass have a low dielectric constant and a low softening point, which allows for better wetting between glass and ceramic during sintering. Compared with the microcrystalline glass system, the ceramic plus glass system has higher mechanical strength, more stable material performance, and easier control of material batch differences. It is the preferred solution when designing commercial LTCC materials.

[0004] Currently, two low-dielectric, low-loss LTC systems, glass-ceramics and ceramic + crystallizable glass, crystallize into a low-dielectric, low-loss ceramic phase during sintering. This phase transition is complex. For example, A6M green tape crystallizes into CaSiO3 and CaB2O4 phases during sintering. During sintering, 9k7 green tape not only crystallizes the glass phase itself into LaBO3, but also reacts with the alumina matrix to form a new calcium boroaluminate phase. Furthermore, these systems typically require sintering with Ag, Cu, or Au conductors, and their low-temperature densification process must be compatible with the sintering of the conductor materials. Otherwise, warping and blistering of the sintered ceramic can occur. Currently, commercial LTCC material systems, such as A6M and 9k7, are primarily glass-ceramics. For example, 9k7 contains over 50% glass-ceramics, while A6M is 100% glass-ceramics. These materials typically exhibit high dielectric losses due to the residual, uncrystallized glass phase during sintering, impacting material performance. Summary of the Invention

[0005] Based on this, and in response to the problems existing in the prior art, the purpose of the present invention is to provide a low-dielectric, low-loss LTCC material, a preparation method thereof, and a green ceramic tape. The low-dielectric, low-loss LTCC material adopts a composite ceramic system of low-temperature sintered ceramic as the ceramic filling phase and a low-melting-point glass phase as a low-sintering aid. Its sintering and densification process is a liquid-phase melting-assisted sintering mechanism. Compared with the microcrystalline glass system, it is relatively easier to co-fire and match with the conductor. In addition, the use of a glass additive with a composition similar to that of the ceramic filling phase can reduce dielectric loss. It is the preferred solution for designing low-dielectric, low-loss LTCC materials.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a low-dielectric, low-loss LTCC material, characterized in that it is prepared by mixing a ceramic filling phase and a glass low-sintering aid, wherein the ceramic filling phase is lanthanum borosilicate microwave dielectric ceramic LaBSiO5, and the glass low-sintering aid is La2O3-B2O3 glass.

[0008] As a further improvement of the above solution of the present invention, the expression of the low-dielectric-low-loss LTCC material is (1-x)LaBSiO5+xLa2O3-B2O3, wherein 0≤x≤0.4.

[0009] As a further improvement of the above solution of the present invention, the main components of the La2O3-B2O3 glass are 20-30wt% La2O3 and 65-80wt% B2O3.

[0010] As a further improvement of the above solution of the present invention, the La2O3-B2O3 glass further includes the following components: 0-3wt% TiO2, 0-1wt% Na2O and / or 0-1wt% Li2O.

[0011] The present invention provides a method for preparing the aforementioned low-dielectric-loss LTCC material, which comprises the following steps:

[0012] S1. According to the chemical formula LaBSiO5, a lanthanum source, a boron source, and a silicon source are weighed and thoroughly mixed. The mixture is wet-milled and then dried and calcined to obtain a powder. The powder is finely ground to obtain a lanthanum borosilicate microwave dielectric ceramic LaBSiO5.

[0013] S2. According to the main component of the glass low-burning aid, 20 to 30 wt% La2O3, 65 to 80 wt% B2O3 weighed lanthanum source, boron source and lanthanum source, boron source after dry mixing, melted to form glass slag, ball milling, to obtain La2O3-B2O3 glass;

[0014] S3. After the lanthanum borosilicate microwave dielectric ceramic LaBSiO5 is fully mixed with the La2O3-B2O3 glass, a low-dielectric and low-loss LTCC material is obtained.

[0015] As a further improvement of the above solution of the present invention, in step S1, the lanthanum source, the boron source, and the silicon source are La2O3, H3BO3, and SiO2 respectively;

[0016] And / or, in step S1, the calcination is performed at 950° C. to 1050° C. for 4-6 hours;

[0017] And / or, in step S1, the fine grinding is to place LaBSiO5 powder, ball milling balls and water in a planetary ball mill in a mass ratio of 1:2:2 and ball mill at a speed of 350-400 r / min for 4-6 hours to obtain lanthanum borosilicate microwave dielectric ceramic LaBSiO5 with a particle size of D50:1.5-3.0 μm.

[0018] As a further improvement of the above solution of the present invention, in step S2, the lanthanum source and the boron source are La2O3 and H3BO3 respectively;

[0019] And / or, in step S2, the melting is carried out at a temperature of 1100° C. to 1200° C. and a temperature of 30 to 60 minutes;

[0020] And / or, in step S2, the particle size of the glass low-sintering aid is D50 to 3.0±0.5 μm.

[0021] As a further improvement of the above solution of the present invention, in step S3, the mixing ratio of the lanthanum borosilicate microwave dielectric ceramic LaBSiO5 and the La2O3-B2O3 glass is 1-x:x, 0≤x≤0.4, calculated by mass ratio.

[0022] The present invention provides a green ceramic tape, which is prepared from the aforementioned low-dielectric-low-loss LTCC material, or prepared from the low-dielectric-low-loss LTCC material prepared by the aforementioned preparation method.

[0023] As a further improvement of the above-mentioned solution of the present invention, the preparation method of the green porcelain tape is: mixing the low-dielectric, low-loss LTCC material with ethanol, isopropyl alcohol, butanone, a dispersant, dibutyl phthalate, and an adhesive to obtain a casting slurry, ball-milling the casting slurry and degassing it, and then casting to obtain the green porcelain tape.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The low-dielectric, low-loss LTCC material of the present invention uses lanthanum borosilicate microwave dielectric ceramics with low dielectric, low loss characteristics and a low sintering temperature (<1200°C) as the ceramic filling phase. The lanthanum borosilicate system has LaBSiO5 as the main crystalline phase. LaBSiO5 ceramics can be sintered densely in the range of 1100°C to 1200°C and have a low dielectric constant (ε r <7.0), and Q×f is about 50000GHz, which is a potential ceramic filling phase for low-dielectric and low-loss LTCC materials; La2O3-B2O3 glass is used as a glass low-sintering aid. La2O3-B2O3 glass has a low softening point and forms a liquid phase in the early stage of sintering to promote the flow and mass transfer of particles, thereby reducing the porosity of the sintered ceramic; during the sintering process, the La2O3-B2O3 in the liquid phase glass will partially form LaBSiO5 phase and LaBO3 phase with the residual SiO2 second phase in the ceramic, while reducing the residual second phase in the ceramic matrix and increasing the crystallization degree of La2O3-B2O3 glass, further reducing the loss of the ceramic glass system; the dielectric constant of the LaBO3 phase is about 7.5, and Q×f is about 70000GHz, which has the characteristics of low dielectric and low loss, can significantly reduce the dielectric loss of the glass system, thereby making this glass-ceramic composite system have the characteristics of low dielectric and low loss.

[0026] 2. The present invention adopts a multiphase ceramic system with low-temperature sintering ceramic as the ceramic filling phase and a low-melting-point glass phase as a low-sintering aid. Its sintering and densification process is a liquid-phase melting-assisted sintering mechanism. Compared with the microcrystalline glass system, it is relatively easier to co-fire and match with the conductor. In addition, the use of a glass additive with a composition similar to that of the ceramic filling phase can reduce dielectric loss, making it the preferred solution for designing low-dielectric and low-loss LTCC materials.

[0027] 3. By controlling the ratio of La2O3-B2O3 glass in the ceramic glass system, the present invention can effectively reduce the sintering temperature of the multiphase system, allowing the LaBSiO5-based material to be sintered within a temperature range below 900°C with excellent microwave dielectric properties, thereby enabling the LTCC substrate material prepared using LTCC green tape to have a lower dielectric constant and dielectric loss.

[0028] 4. The (1-x)LaBSiO5+xLa2O3-B2O3 glass-ceramic material prepared by the present invention can be sintered at a relatively low temperature range of 850°C to 900°C, has a dielectric constant of 5.7 to 6.7 (30 GHz), and a dielectric loss of 0.0015 to 0.0028 (30 GHz), which meets the microwave dielectric performance requirements of the circuit for the substrate material and the sintering temperature requirements for co-firing with silver. In addition, when the substrate material is co-fired with silver, it does not chemically react with silver, thus meeting the chemical compatibility requirements for co-firing with silver, and thus can well achieve low-temperature co-firing with silver electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the XRD pattern of the ceramic substrate prepared in Example 4 of the present invention;

[0030] Figure 2 This is a cross-sectional SEM image of the ceramic substrate prepared in Example 4 of the present invention;

[0031] Figure 3 This is a cross-sectional SEM image of the low-dielectric, low-loss LTCC material obtained in Example 4 of the present invention after co-firing with Ag;

[0032] Figure 4 This is a cross-sectional composition analysis diagram of the low-dielectric, low-loss LTCC material obtained in Example 4 of the present invention after co-firing with Ag. DETAILED DESCRIPTION

[0033] To facilitate understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0035] Example 1

[0036] This embodiment provides a green porcelain tape, the preparation method of which includes the following steps:

[0037] S1. Preparation of LaBSiO5 powder: La2O3, H3BO3, and SiO2 powders are used as raw materials and weighed according to the stoichiometric ratio of the chemical formula LaBSiO5. After wet mixing and ball milling for 12 hours, the mixture is dried and calcined at 1000°C for 4 hours to obtain powder. The powder, zirconia balls, and water are placed in a planetary ball mill at a mass ratio of 1:2:2 and finely ground at a speed of 400 r / min for 6 hours to obtain LaBSiO5 powder with a particle size of D50: 2.0±0.3μm.

[0038] S2. Preparation of La2O3-B2O3 glass powder: La2O3 and H3BO3 powder are used as raw materials, and the ingredients are prepared according to the La2O3-B2O3 glass composition of 20wt% La2O3, 78wt% B2O3, 1wt% TiO2, 0.5wt% Na2O, and 0.5wt% Li2O. After the raw materials are dry-mixed for 12 hours, they are placed in a platinum crucible and melted at 1100°C for 40 minutes. The molten glass liquid is poured into deionized water to make glass slag, and the glass slag is ground into La2O3-B2O3 glass powder with a D50 of about 3.0±0.5μm by planetary ball milling.

[0039] S3. Low-dielectric-low-loss LTCC material configuration: The LaBSiO5 powder obtained in step S1 and the La2O3-B2O3 glass powder obtained in step S2 are fully mixed in a ratio of 72wt% LaBSiO5+28wt% La2O3-B2O3 (x=0.28) according to the chemical composition expression to obtain a low-dielectric-low-loss LTCC material.

[0040] S4. Preparation of LTCC green tape: The low-dielectric-low-loss LTCC material obtained in step S3 is mixed with ethanol, isopropyl alcohol, butanone, BYK110 dispersant, dibutyl phthalate, and B60H adhesive to prepare a casting slurry, wherein the casting slurry contains: 57.9% low-dielectric-low-loss LTCC material, 23.2% ethanol, 5.8% isopropyl alcohol, 5.8% butanone, 1.2% BYK110 dispersant, 1.4% dibutyl phthalate, and 4.7% B60H adhesive; the casting slurry is ball-milled in a ball mill at a rotation speed of 60 r / min for 24 h, and then the casting slurry is degassed and cast in a casting machine into a green tape with a thickness of 125 μm ± 5 μm.

[0041] The green porcelain tape produced in this example was fabricated into a ceramic substrate: 20 sheets of the green porcelain tape were cut and laminated into 75 mm × 75 mm × 2.5 mm green sheets. The green sheets were then debinded at 450°C and sintered at 850°C to form the ceramic substrate. Performance testing of the ceramic substrate produced in this example revealed a dielectric constant of 6.3 and a dielectric loss of 0.0019 at 30 GHz.

[0042] Example 2

[0043] This embodiment provides a green porcelain tape, the preparation method of which includes the following steps:

[0044] S1. Preparation of LaBSiO5 powder: La2O3, H3BO3, and SiO2 powders are used as raw materials and weighed according to the stoichiometric ratio of the chemical formula LaBSiO5. After wet mixing and ball milling for 12 hours, the mixture is dried and calcined at 1000°C for 4 hours to obtain powder. The powder, zirconia balls, and water are placed in a planetary ball mill at a mass ratio of 1:2:2 and finely ground at a speed of 400 r / min for 6 hours to obtain LaBSiO5 powder with a particle size of D50: 2.0±0.3μm.

[0045] S2. Preparation of La2O3-B2O3 glass powder: La2O3 and H3BO3 powder are used as raw materials, and the ingredients are prepared according to the La2O3-B2O3 glass composition of 23wt% La2O3, 75wt% B2O3, 1wt% TiO2, 0.5wt% Na2O, and 0.5wt% Li2O. After the raw materials are dry-mixed for 12 hours, they are placed in a platinum crucible and melted at 1100°C for 40 minutes. The molten glass liquid is poured into deionized water to make glass slag, and the glass slag is ground into La2O3-B2O3 glass powder with a D50 of about 3.0±0.5μm by planetary ball milling.

[0046] S3. Low-dielectric-low-loss LTCC material configuration: The LaBSiO5 powder obtained in step S1 and the La2O3-B2O3 glass powder obtained in step S2 are fully mixed in a ratio of 68wt% LaBSiO5+32wt% La2O3-B2O3 (x=0.32) according to the chemical composition expression to obtain a low-dielectric-low-loss LTCC material.

[0047] S4. Preparation of LTCC green tape: low dielectric, low loss LTCC material is mixed with ethanol, isopropyl alcohol, butanone, BYK110 dispersant, dibutyl phthalate, and B60H adhesive to prepare a casting slurry, the casting slurry containing: 57.9% low dielectric, low loss LTCC material, 23.2% ethanol, 5.8% isopropyl alcohol, 5.8% butanone, 1.2% BYK110 dispersant, 1.4% dibutyl phthalate, and 4.7% B60H adhesive; the casting slurry is ball milled in a ball mill at a rotation speed of 60 r / min for 24 hours, and then the casting slurry is degassed and cast in a casting machine into a green tape with a thickness of 125 μm ± 5 μm.

[0048] The green porcelain tape produced in this example was fabricated into a ceramic substrate: 20 sheets of the green porcelain tape were cut and laminated into 75 mm × 75 mm × 2.5 mm green sheets. The green sheets were then debinded at 450°C and sintered at 850°C to form the ceramic substrate. Performance testing of the ceramic substrate produced in this example revealed a dielectric constant of 5.9 and a dielectric loss of 0.0017 at 30 GHz.

[0049] Example 3

[0050] This embodiment provides a green porcelain tape, the preparation method of which includes the following steps:

[0051] S1. Preparation of LaBSiO5 powder: La2O3, H3BO3, and SiO2 powders are used as raw materials and weighed according to the stoichiometric ratio of the chemical formula LaBSiO5. After wet mixing and ball milling for 12 hours, the mixture is dried and calcined at 1000°C for 4 hours to obtain powder. The powder, zirconia balls, and water are placed in a planetary ball mill at a mass ratio of 1:2:2 and finely ground at a speed of 400 r / min for 6 hours to obtain LaBSiO5 powder with a particle size of D50: 2.0±0.3μm.

[0052] S2. Preparation of La2O3-B2O3 glass powder: La2O3 and H3BO3 powder are used as raw materials, and the ingredients are prepared according to the La2O3-B2O3 glass composition of 27wt% La2O3, 70wt% B2O3, 2wt% TiO2, 0.5wt% Na2O, and 0.5wt% Li2O. After the raw materials are dry-mixed for 12 hours, they are placed in a platinum crucible and melted at 1100°C for 40 minutes. The molten glass liquid is poured into deionized water to make glass slag, and the glass slag is ground into La2O3-B2O3 glass powder with a D50 of about 3.0±0.5μm by planetary ball milling.

[0053] S3. Low-dielectric-low-loss LTCC material configuration: The LaBSiO5 powder obtained in step S1 and the La2O3-B2O3 glass powder obtained in step S2 are fully mixed in a ratio of 64wt% LaBSiO5+36wt% La2O3-B2O3 (x=0.36) according to the chemical composition expression to obtain a low-dielectric-low-loss LTCC material.

[0054] S4. Preparation of LTCC green tape: low dielectric, low loss LTCC material is mixed with ethanol, isopropyl alcohol, butanone, BYK110 dispersant, dibutyl phthalate, and B60H adhesive to prepare a casting slurry, the casting slurry containing: 57.9% low dielectric, low loss LTCC material, 23.2% ethanol, 5.8% isopropyl alcohol, 5.8% butanone, 1.2% BYK110 dispersant, 1.4% dibutyl phthalate, and 4.7% B60H adhesive; the casting slurry is ball milled in a ball mill at a rotation speed of 60 r / min for 24 hours, and then the casting slurry is degassed and cast in a casting machine into a green tape with a thickness of 125 μm ± 5 μm.

[0055] The green porcelain tape produced in this example was fabricated into a ceramic substrate: 20 sheets of the green porcelain tape were cut and laminated into 75 mm × 75 mm × 2.5 mm green sheets. The green sheets were then debinded at 450°C and sintered at 850°C to form the ceramic substrate. Performance testing of the ceramic substrate produced in this example revealed a dielectric constant of 6.7 and a dielectric loss of 0.0023 at 30 GHz.

[0056] Example 4

[0057] This embodiment provides a green porcelain tape, the preparation method of which includes the following steps:

[0058] S1. Preparation of LaBSiO5 powder: La2O3, H3BO3, and SiO2 powders are used as raw materials and weighed according to the stoichiometric ratio of the chemical formula LaBSiO5. After wet mixing and ball milling for 12 hours, the mixture is dried and calcined at 1000°C for 4 hours to obtain powder. The powder, zirconia balls, and water are placed in a planetary ball mill at a mass ratio of 1:2:2 and finely ground at a speed of 400 r / min for 6 hours to obtain LaBSiO5 powder with a particle size of D50: 2.0±0.3μm.

[0059] S2. Preparation of La2O3-B2O3 glass powder: La2O3 and H3BO3 powder are used as raw materials, and the ingredients are prepared according to the La2O3-B2O3 glass composition of 30wt% La2O3, 67wt% B2O3, 2wt% TiO2, 0.51wt% Na2O, and 0.5wt% Li2O. After the raw materials are dry-mixed for 12 hours, they are placed in a platinum crucible and melted at 1100°C for 40 minutes. The molten glass liquid is poured into deionized water to make glass slag, and the glass slag is ground into La2O3-B2O3 glass powder with a diameter of about D50 ~ 3.0±0.5μm by planetary ball milling.

[0060] S3. Low-dielectric-low-loss LTCC material configuration: The LaBSiO5 powder obtained in step S1 and the La2O3-B2O3 glass powder obtained in step S2 are fully mixed in a ratio of 60wt% LaBSiO5+40wt% La2O3-B2O3 (x=0.40) according to the chemical composition expression to obtain a low-dielectric-low-loss LTCC material.

[0061] S4. Preparation of LTCC green tape: low dielectric, low loss LTCC material is mixed with ethanol, isopropyl alcohol, butanone, BYK110 dispersant, dibutyl phthalate, and B60H adhesive to prepare a casting slurry, the casting slurry containing: 57.9% low dielectric, low loss LTCC material, 23.2% ethanol, 5.8% isopropyl alcohol, 5.8% butanone, 1.2% BYK110 dispersant, 1.4% dibutyl phthalate, and 4.7% B60H adhesive; the casting slurry is ball milled in a ball mill at a rotation speed of 60 r / min for 24 hours, and then the casting slurry is degassed and cast in a casting machine into a green tape with a thickness of 125 μm ± 5 μm.

[0062] The green porcelain tape produced in this example was fabricated into a ceramic substrate: 20 sheets of the green porcelain tape were cut and laminated into 75 mm × 75 mm × 2.5 mm green sheets. The green sheets were then debinded at 450°C and sintered at 850°C to form the ceramic substrate. Performance testing of the ceramic substrate produced in this example revealed a dielectric constant of 7.3 and a dielectric loss of 0.0025 at 30 GHz. Figure 1 The XRD pattern of the ceramic substrate prepared in this embodiment is as follows: Figure 1 It can be seen that the main crystalline phase of the composite ceramic is LaBSiO5 phase. In addition, due to the addition of La2O3-B2O3 glass, a small amount of LaBO3 phase is precipitated. Figure 2 The cross-sectional SEM image of the ceramic substrate obtained in this embodiment is shown in FIG. Figure 2 It can be seen that the ceramics are denser and have lower porosity after sintering at 850°C, forming a dense ceramic body, which shows that this ceramic system can be sintered at 850°C.

[0063] The green porcelain tape prepared in this embodiment is made into a ceramic substrate: 20 pieces of the green porcelain tape prepared in this embodiment are cut and stacked into 75mm×75mm×2.5mm green sheets. The conductor pattern is printed on the surface of the green sheet using Ag conductor (Ferro's 33-398Ag inner layer conductor paste). The green sheet is debonded at 450°C and sintered at 850°C to form a ceramic substrate. Figure 3 The cross-sectional SEM image of the low dielectric and low loss LTCC material obtained in this embodiment after co-firing with Ag. Figure 3 It can be seen that the interface between LTCC material and Ag is relatively clear, the dark substance is the ceramic matrix phase, and the light substance is the Ag conductor phase. No second phase is produced, and co-firing with the Ag conductor can be achieved. Figure 4 The cross-sectional composition analysis diagram of the low dielectric and low loss LTCC material obtained in this embodiment after co-firing with Ag. Figure 4 It can be seen that the materials at the interface are the main components of the ceramic matrix and Ag, and there is no obvious phenomenon of Ag conductor diffusing into the ceramic matrix.

[0064] Comparative Example 1

[0065] This comparative example proposes a green porcelain tape, the preparation method of which comprises the following steps:

[0066] S1. Preparation of LaBSiO5 powder: La2O3, H3BO3, and SiO2 powders are used as raw materials and weighed according to the stoichiometric ratio of the chemical formula LaBSiO5. After wet mixing and ball milling for 12 hours, the mixture is dried and calcined at 1000°C for 4 hours to obtain powder. The powder, zirconia balls, and water are placed in a planetary ball mill at a mass ratio of 1:2:2 and finely ground at a speed of 400 r / min for 6 hours to obtain LaBSiO5 powder with a particle size of D50: 2.5±0.3μm.

[0067] S2. Preparation of CaO-SiO2-B2O3 glass powder: Using CaCO3, SiO2, and H3BO3 powders as raw materials, the ingredients are prepared according to the CaO-SiO2-B2O3 glass composition of 43wt% CaCO3, 30wt% SiO2, and 27wt% H3BO3. After the raw materials are dry-mixed for 12 hours, they are placed in a platinum crucible and melted at 1400°C for 40 minutes. The molten glass liquid is poured into deionized water to make glass slag, which is then ground into La2O3-B2O3 glass powder with a D50 of about 3.5±0.5μm by planetary ball milling.

[0068] S3. Low-dielectric-low-loss LTCC material configuration: The LaBSiO5 powder obtained in step S1 and the CaO-SiO2-B2O3 glass powder obtained in step S2 are fully mixed in a ratio of 55wt% LaBSiO5+45wt% CaO-SiO2-B2O3 (x=0.45) according to the chemical composition expression to obtain a low-dielectric-low-loss LTCC material.

[0069] S4. Preparation of LTCC green tape: low dielectric, low loss LTCC material is mixed with ethanol, isopropyl alcohol, butanone, BYK110 dispersant, dibutyl phthalate, and B60H adhesive to prepare a casting slurry, the casting slurry containing: 57.9% low dielectric, low loss LTCC material, 23.2% ethanol, 5.8% isopropyl alcohol, 5.8% butanone, 1.2% BYK110 dispersant, 1.4% dibutyl phthalate, and 4.7% B60H adhesive; the casting slurry is ball milled in a ball mill at a rotation speed of 60 r / min for 24 hours, and then the casting slurry is degassed and cast in a casting machine into a green tape with a thickness of 125 μm ± 5 μm.

[0070] The green porcelain tape prepared in this comparative example was made into a ceramic substrate: 20 pieces of the green porcelain tape prepared in this comparative example were cut and stacked into 75mm×75mm×2.5mm green billets, and a conductor pattern was printed on the surface of the green billet using an Ag conductor (Ferro's 33-398Ag inner layer conductor slurry). The green billet was debonded at 450°C and sintered at 850°C to form a ceramic substrate.

[0071] Performance testing of the ceramic substrate produced in this comparative example revealed a dielectric constant of 6.9 and a dielectric loss of 0.0033 at 30 GHz. Analysis of the interface between the substrate and the silver conductor co-fired in this comparative example revealed significant substrate warpage, indicating significant differences in the sintering densification processes between the LTCC material and the silver conductor, resulting in a sintering mismatch.

[0072] Comparative Example 2

[0073] This comparative example proposes a green porcelain tape, the preparation method of which comprises the following steps:

[0074] S1. Preparation of LaBSiO5 powder: La2O3, H3BO3, and SiO2 powders are used as raw materials and weighed according to the stoichiometric ratio of the chemical formula LaBSiO5. After wet mixing and ball milling for 12 hours, the mixture is dried and calcined at 1000°C for 4 hours to obtain powder. The powder, zirconia balls, and water are placed in a planetary ball mill at a mass ratio of 1:2:2 and finely ground at a speed of 400 r / min for 6 hours to obtain LaBSiO5 powder with a particle size of D50: 2.5±0.3μm.

[0075] S2. Low-dielectric-loss LTCC material configuration: The LaBSiO5 powder prepared in step S1 is fully mixed with the B2O3-ZnO composite low-calcination aid powder according to the chemical composition expression of 88wt% LaBSiO5+7.5wt% B2O3+4.5wt% ZnO to obtain a low-dielectric-loss LTCC material.

[0076] S3. Preparation of LTCC green tape: low-dielectric-loss LTCC material is mixed with ethanol, isopropyl alcohol, butanone, BYK110 dispersant, dibutyl phthalate, and B60H adhesive to prepare a casting slurry, wherein the casting slurry contains: 57.1% low-dielectric-loss LTCC material, 23.2% ethanol, 5.8% isopropyl alcohol, 5.8% butanone, 1.2% BYK110 dispersant, 1.4% dibutyl phthalate, and 5.5% B60H adhesive; the casting slurry is ball-milled in a ball mill at a rotation speed of 60 r / min for 24 hours, and then the casting slurry is degassed and cast in a casting machine into a green tape with a thickness of 125 μm ± 5 μm.

[0077] The green porcelain tape prepared in this comparative example was made into a ceramic substrate: 20 pieces of the green porcelain tape prepared in this comparative example were cut and stacked into 75mm×75mm×2.5mm green billets, and a conductor pattern was printed on the surface of the green billet using an Ag conductor (Ferro's 33-398Ag inner layer conductor slurry). The green billet was debonded at 450°C and sintered at 850°C to form a ceramic substrate.

[0078] Performance testing of the ceramic substrate produced in this comparative example revealed a dielectric constant of 6.0 and a dielectric loss of 0.0065 at 30 GHz. Analysis of the interface between the co-fired substrate and the silver conductor revealed satisfactory flatness, but exhibited significant overall yellowing, particularly around the Ag conductor. This suggests Ag diffusion into the ceramic matrix during the sintering process, indicating a mismatch between the LTCC material and the Ag conductor.

[0079] From Comparative Examples 1 and 2, it can be seen that using LaBSiO5 ceramic as the matrix material and other glass materials or other low-melting-point oxides as low-sintering aids can also reduce the sintering temperature, but there is a phenomenon of mismatch with the sintering of Ag conductors.

[0080] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A low dielectric and low loss LTCC material, characterized in that: It is prepared by mixing a ceramic filling phase and a glass low-sintering aid, wherein the ceramic filling phase is lanthanum borosilicate microwave dielectric ceramic LaBSiO5, the glass low-sintering aid is La2O3-B2O3 glass, and the main components of the La2O3-B2O3 glass are 20~30wt% La2O3 and 65~80wt% B2O3.

2. The low-dielectric-loss LTCC material according to claim 1, characterized in that: The expression of the low dielectric constant and low loss LTCC material is (1-x)LaBSiO5+xLa2O3-B2O3, wherein 0 <x≤0.4。 3. The low-dielectric-loss LTCC material according to claim 1, characterized in that: The La2O3-B2O3 glass further includes the following components: 0-3 wt% TiO2, 0-1 wt% Na2O and / or 0-1 wt% Li2O.

4. A method for preparing a low dielectric constant and low loss LTCC material according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: S1. According to the chemical formula LaBSiO5, a lanthanum source, a boron source, and a silicon source are weighed and thoroughly mixed. The mixture is wet-milled and then dried and calcined to obtain a powder. The powder is finely ground to obtain a lanthanum borosilicate microwave dielectric ceramic LaBSiO5. S2. According to the main components of the glass low-fired additive, 20 to 30 wt% La2O3 and 65 to 80 wt% B2O3, a lanthanum source and a boron source were weighed and the lanthanum source and the boron source were dry-mixed, melted and made into glass slag, and ball-milled to obtain La2O3-B2O3 glass; S3. After the lanthanum borosilicate microwave dielectric ceramic LaBSiO5 is fully mixed with the La2O3-B2O3 glass, a low-dielectric and low-loss LTCC material is obtained.

5. The method for preparing the low-dielectric-loss LTCC material according to claim 4, characterized in that: In the step S1, the lanthanum source, the boron source, and the silicon source are La2O3, H3BO3, and SiO2 respectively; And / or, in step S1, the calcination is performed at 950° C. to 1050° C. for 4-6 hours; And / or, in step S1, the fine grinding is to place LaBSiO5 powder, ball milling balls, and water in a planetary ball mill in a mass ratio of 1:2:2 and ball mill at a rotation speed of 350-400 r / min for 4-6 hours to obtain lanthanum borosilicate microwave dielectric ceramic LaBSiO5 with a particle size of D50:1.5-3.0 μm.

6. The method for preparing the low-dielectric-loss LTCC material according to claim 4, characterized in that: In the step S2, the lanthanum source and the boron source are La2O3 and H3BO3 respectively; And / or, in step S2, the melting is carried out at a temperature of 1100° C. to 1200° C. and a temperature of 30 to 60 minutes; And / or, in step S2, the particle size D50 of the glass low-sintering aid is 3.0±0.5 μm.

7. The method for preparing the low-dielectric-loss LTCC material according to claim 4, characterized in that: In the step S3, the mixing ratio of the lanthanum borosilicate microwave dielectric ceramic LaBSiO5 and the La2O3-B2O3 glass is 1-x:x, 0 <x≤0.4。 8. A green porcelain tape, characterized in that: It is prepared from the low-dielectric-low-loss LTCC material according to any one of claims 1 to 3, or prepared from the low-dielectric-low-loss LTCC material prepared by the preparation method according to any one of claims 4 to 7.

9. The green porcelain tape according to claim 8, characterized in that The preparation method of the green porcelain tape comprises the following steps: mixing the low-dielectric-low-loss LTCC material with ethanol, isopropyl alcohol, butanone, a dispersant, dibutyl phthalate, and an adhesive to obtain a casting slurry; ball-milling the casting slurry, degassing the casting slurry, and casting the green porcelain tape.

Images