CN116639967B - Low dielectric and low loss composite LTCC material, preparation method and application - Google Patents

Abstract

The invention belongs to the technical field of electronic ceramic materials and manufacturing thereof, and discloses a low dielectric low-loss composite LTCC material, a preparation method and application thereof, wherein the LTCC material is obtained by compounding SrCuSi ₄ O ₁₀ and (Li _0.5 Y _0.5) MoO ₄ by a solid-phase reaction method, so that the problems of low-temperature sintering and temperature coefficient adjustment of resonant frequency can be solved, and meanwhile, the dielectric constant and dielectric loss of the composite material are low, and the low dielectric low-loss requirement is met. The composite material can realize low-temperature sintering at 900 ℃ of a material system without adding any fluxing agent, and meanwhile, the temperature coefficient of the resonant frequency of the material can be adjusted to be within +/-10 ppm/DEG C, the dielectric constant of the material is between 7.7 and 8.0, the Qf value exceeds 46000GHz, and the composite material has good application prospect in LTCC integrated devices and substrates.

Description

A low dielectric and low loss composite LTCC material, preparation method and application

Technical Field

The present invention belongs to the technical field of electronic ceramic materials and their manufacturing, and in particular relates to a low-dielectric and low-loss composite LTCC material, a preparation method and an application thereof.

Background Art

At present, LTCC (low temperature co-fired ceramic) technology is the most mainstream passive integration technology, and it has played a very important role in realizing the miniaturization and integration of electronic components. In addition to electronic components, LTCC technology is also widely used in the field of integrated packaging substrates. In LTCC substrates and LTCC components for high-frequency applications, it is generally required that the dielectric constant of the LTCC material used is not too high (ε _r <10), which helps to reduce the delay time of information transmission; the dielectric loss is as low as possible (high Qf value), which helps to reduce the loss caused by the medium in the device or substrate, and the resonant frequency temperature coefficient τ _f is as close to zero as possible, which helps to reduce the impact of temperature changes on the performance of LTCC devices and substrates.

At present, there are many studies on low-dielectric LTCC materials at home and abroad, and the use of silicate system ceramics to develop low-dielectric LTCC materials has the most obvious advantages, which can better take into account the characteristics of low dielectric and low loss. Typical silicate LTCC material systems include Mg ₂ SiO ₄ , Zn ₂ SiO ₄ , Li ₂ MgSiO ₄ , CaMgSi ₂ O ₆ , BaCuSi ₄ O ₁₀ , etc. with different ion substitutions. Among these silicates, BaCuSi ₄ O ₁₀ or SrCuSi ₄ O ₁₀ with Sr replacing Ba has the characteristics of low sintering temperature (1100℃), low dielectric constant (5.5～6), high Qf value (BaCuSi ₄ O ₁₀ can reach 50000GHz, SrCuSi ₄ O ₁₀ can reach about 80000GHz), etc., which has outstanding advantages in the research and development of low-dielectric LTCC materials. However, in order to reduce the material to the 900℃ low-temperature sintering required by the LTCC process, various fluxes need to be added. At the same time, it also has a large negative resonant frequency temperature coefficient, so other means are needed to adjust the resonant frequency temperature coefficient. The conventional method of adjusting the temperature coefficient is to compound it with positive temperature coefficient materials such as CaTiO ₃ and TiO _2. Since these positive temperature coefficient materials not only have large dielectric losses, but also high dielectric constants and high sintering temperatures, the low-temperature sintering of the material system will be more difficult after compounding. More flux is needed to be doped to assist sintering in order to achieve low-temperature sintering. In addition, the Qf value of the material system will be significantly reduced, and the dielectric constant will be significantly increased, making it difficult to reflect the advantages of low-dielectric materials.

Through the above analysis, the problems and defects of the prior art are as follows:

In addition to the problems in adjusting the temperature coefficient, the existing LTCC technology also has some other shortcomings and problems. For example, among the existing LTCC materials, although the use of silicate system ceramics to develop low-dielectric LTCC materials has become a mainstream method, there are still some limitations. First, although the dielectric constant of the silicate LTCC material system is generally low, in order to adjust the temperature coefficient, it is necessary to compound common positive temperature coefficient materials such as CaTiO ₃ and TiO ₂ , and these materials have high dielectric constants and low Qf values, which will lead to an increase in the dielectric constant of the composite material and a significant decrease in the Qf value. Second, the sintering temperature of the conventional silicate material system is still relatively high, so it is necessary to add a flux to reduce the sintering temperature to around 900°C, and the addition of the flux will also lead to a decrease in the Qf value of the material system.

Summary of the invention

In view of the problems existing in the prior art, the present invention provides a low-dielectric and low-loss composite LTCC material, a preparation method and an application thereof.

The present invention is achieved by providing a low dielectric and low loss LTCC composite material, which is composed of two phases _{of SrCuSi4O10} and ( _Li0.5Y0.5 )MoO4 _. When compounding, the weight ratio of the two-phase pre-sintered materials is ( ₁₀₀ - _x )% _SrCuSi4O10 +x% ( _Li0.5Y0.5 ) _MoO4 , where _17≤x≤21 .

Furthermore, the sintering temperature of the low-dielectric and low-loss LTCC composite material is 880-920°C, ε _r =7.7-8.1, Q×f value is 46,000-53,000 GHz, and τ _f =-10-10 ppm/°C.

Another object of the present invention is to provide a method for preparing the low-dielectric-loss LTCC composite material, the method for preparing the low-dielectric-loss LTCC composite material comprising the following steps:

Step 1: Prepare analytically pure SrCO ₃ , CuO and SiO ₂ in a molar ratio; then perform a ball milling to mix the ingredients evenly; add deionized water and ball milling medium in a mass ratio of 1:1-2:4-6; perform ball milling for 4-6 hours at a planetary ball mill speed of 250-300 rpm; and dry the obtained powder at 100-120° C. for standby use;

Step 2: sieve the dried powder obtained in step 1, put it into a crucible and compact it, and pre-sinter it at a heating rate of 2-5°C/min to 900-1000°C, keep it at that temperature for 2-4h, and cool it in the furnace to obtain SrCuSi ₄ O ₁₀ pre-sintered material;

Step 3: Prepare analytically pure Li ₂ CO ₃ , Y ₂ O ₃ and MoO ₃ in a molar ratio; ball-mill the prepared raw materials to make the ingredients uniformly mixed, add deionized water and ball-milling medium in a mass ratio of 1:1-2:4-6, mill at a ball-milling speed of 250-300 rpm for 4-6 hours, and dry the obtained powder at 100-120°C for standby use;

Step 4: sieve the dried powder obtained in step 3, put it into a crucible and compact it, raise the temperature to 500-600°C for pre-calcination, keep it warm for 2-4 hours, and cool it with the furnace to obtain (Li _0.5 Y _0.5 )MoO ₄ pre-calcined material;

Step 5, the SrCuSi ₄ O ₁₀ pre-calcined material and the (Li _0.5 Y _0.5 )MoO ₄ pre-calcined material obtained in step 2 and step 4 are weighed and prepared according to the weight ratio of (100-x)% SrCuSi ₄ O ₁₀ +x% (Li _0.5 Y _0.5 )MoO ₄ , and then deionized water and ball milling medium are added according to the mass ratio of 1:1-2:4-6, and the ball milling speed is 250-300rpm, and the ball milling is carried out for 6-12h. After the ball milling, the powder is dried at 100-120°C for standby use;

Step 6: Add 15wt% to 25wt% of PVA solution as a binder to the dried powder obtained in step 5, granulate it and perform uniaxial dry pressing at 10 to 20MPa;

Step 7: Place the product obtained in step 6 into a sintering furnace, heat it to 200°C at a heating rate of 2-5°C/min, keep it warm for 1-4 hours to drain water, then heat it to 400-600°C to drain the binder for 2-6 hours, then heat it to 880-920°C to keep it warm for 2-5 hours, cool it to room temperature with the furnace, and obtain a test sample.

Furthermore, in the step 1, analytically pure SrCO ₃ , CuO and SiO ₂ are mixed in a molar ratio of SrCO ₃ :CuO:SiO ₂ =1:1:4.

Furthermore, in the step 2, the dried powder obtained in the step 1 is passed through a 40-80 mesh sieve.

Furthermore, in step three, analytically pure Li ₂ CO ₃ , Y ₂ O ₃ and MoO ₃ are mixed in a molar ratio of Li ₂ CO ₃ :Y ₂ O ₃ :MoO ₃ =1:1:4.

Furthermore, in the step 4, the dried powder obtained in the step 3 is passed through a 40-80 mesh sieve, placed in a crucible for compaction, and pre-sintered at a heating rate of 2-5°C/min to 500-600°C.

Furthermore, the concentration of the PVA solution in step six is 8-10wt%.

Another object of the present invention is to provide an application of the low-dielectric and low-loss LTCC composite material in LTCC integrated devices.

Another object of the present invention is to provide an application of the low-dielectric and low-loss LTCC composite material in a substrate.

In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

First, the present invention adopts the method of compounding SrCuSi ₄ O ₁₀ and (Li _0.5 Y _0.5 )MoO ₄ to achieve the goal of simultaneously solving the problems of low-temperature sintering and adjusting the temperature coefficient of the resonant frequency. At the same time, the dielectric constant and dielectric loss of the composite material are also very low, meeting the requirements of low dielectric and low loss. The composite material can achieve low-temperature sintering of the material system at about 900°C without adding any flux. At the same time, the resonant frequency temperature coefficient of the material can also be adjusted to within ±10ppm/°C. The dielectric constant of the material is also between 7.7 and 8.1, and the Qf value exceeds 46000GHz, which has a good application prospect in LTCC integrated devices and substrates.

Second, the LTCC material provided by the present invention is obtained by compounding an appropriate amount of SrCuSi ₄ O ₁₀ and (Li _0.5 Y _0.5 )MoO ₄ in a certain proportion. The advantages of the SrCuSi ₄ O ₁₀ material have been introduced above, and the use of (Li _0.5 Y _0.5 )MoO ₄ for compounding is based on the following considerations: First, the dielectric constant of the (Li _0.5 Y _0.5 )MoO ₄ material itself is not high, only about 19, and the dielectric loss is also low, and it has a large positive resonant frequency temperature coefficient. When it is compounded with SrCuSi ₄ O ₁₀ ceramics, while adjusting the resonant frequency temperature coefficient, the dielectric constant of the composite material will not be increased too much, and the dielectric loss of the composite material can also be maintained at a very low level; secondly, (Li _0.5 Y _0.5 )MoO The densification temperature of ₄ is relatively low, and it can be densified by sintering at about 780℃. Experiments have found that when the composite ratio of the two phases is adjusted to make the temperature coefficient of the composite ceramic close to zero, the composite material composed of the two can also achieve low-temperature sintering densification at about 900℃. Therefore, there is no need to add other low-melting sintering aids to promote the low-temperature sintering of the material system, which is more conducive to improving the comprehensive dielectric properties of the material. The temperature coefficient can be adjusted and low-temperature sintering can be achieved simultaneously within our composite range. In addition, the two phases do not react chemically with each other to form a new phase when they are composited, which also helps to obtain excellent microwave dielectric properties. Finally, neither of these two ceramics contains expensive raw materials, which is also conducive to reducing the research and development cost of the material and is more suitable for mass production.

In summary, the low dielectric constant, low loss and near-zero temperature coefficient LTCC material provided by the present invention has many advantages and has a good application prospect.

Third, the expected benefits and commercial value after the technical solution of the present invention is as follows: the present invention can achieve low-temperature sintering and resonant frequency temperature coefficient approaching zero of the LTCC material system without adding flux, so as to better take into account the requirements of comprehensive material performance (low-temperature sintering, low dielectric loss, near-zero resonant frequency temperature coefficient, and no negative effects of flux), and is expected to be applied in LTCC microwave integrated devices, such as LTCC filters, power dividers, baluns, antennas and other devices, and can also be used in LTCC multi-layer substrates or modules. Replace the currently used microcrystalline glass or glass + ceramic composite LTCC material system and achieve good market benefits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a method for preparing a low-dielectric and low-loss composite LTCC material provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a method for preparing a low-dielectric and low-loss composite LTCC material provided in an embodiment of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

The low-dielectric and low-loss composite LTCC material provided in an embodiment of the present invention comprises two phases of SrCuSi ₄ O ₁₀ and (Li _0.5 Y _0.5 )MoO _4. When composited, the weight ratio of the pre-sintered material is (100-x)% SrCuSi ₄ O ₁₀ +x% (Li _0.5 Y _0.5 )MoO ₄ , wherein 17≤x≤21; its sintering temperature is 880-920°C, ε _r =7.7-8.1, Q×f value is 46,000-53,000 GHz, and τ _f =-10-10ppm/°C.

As shown in FIG1 , the method for preparing the low-dielectric and low-loss composite LTCC material provided in an embodiment of the present invention comprises the following steps:

S101: analytically pure SrCO ₃ , CuO and SiO ₂ are prepared in a molar ratio of SrCO ₃ :CuO:SiO ₂ =1:1:4; then they are ball-milled once to make the ingredients uniformly mixed, deionized water and ball-milling medium are added in a mass ratio of 1:1-2:4-6 to the ingredients, and the mixture is ball-milled for 4-6 hours at a planetary ball mill speed of 250-300 rpm. After ball-milling, the obtained powder is dried at 100-120° C. for standby use;

S102: the dried powder obtained in S101 is passed through a 40-80 mesh screen, and after being sieved, is put into a crucible and compacted, and is pre-sintered at a heating rate of 2-5°C/min to 900-1000°C, and is kept at this temperature for 2-4 hours, and is cooled along with the furnace to obtain a SrCuSi ₄ O ₁₀ pre-sintered material;

S103: analytically pure Li ₂ CO ₃ , Y ₂ O ₃ and MoO ₃ are prepared in a molar ratio of Li ₂ CO ₃ :Y ₂ O ₃ :MoO ₃ =1:1:4; the prepared raw materials are ball-milled once to make the ingredients uniformly mixed, deionized water and ball-milling medium are added according to the mass ratio of the ingredients to deionized water and ball-milling medium of 1:1-2:4-6, the ball-milling is performed at a ball-milling speed of 250-300 rpm for 4-6 hours, and the obtained powder is dried at 100-120° C. for standby use;

S104: the dried powder obtained in S103 is passed through a 40-80 mesh sieve, and after being sieved, is put into a crucible and compacted, and is pre-fired at a heating rate of 2-5°C/min to 500-600°C, and is kept at this temperature for 2-4 hours, and is cooled in the furnace to obtain a (Li _0.5 Y _0.5 )MoO ₄ pre-fired material;

S105: SrCuSi ₄ O ₁₀ pre-calcined material and (Li _0.5 Y _0.5 )MoO ₄ pre-calcined material obtained from S102 and S104 are weighed and prepared according to a weight ratio of (100-x)% SrCuSi ₄ O ₁₀ +x% (Li _0.5 Y _0.5 )MoO ₄ (wherein 17≤x≤21), and then deionized water and ball milling medium are added according to a mass ratio of 1:1-2:4-6, and the mixture is ball milled at a ball milling speed of 250-300 rpm for 6-12 hours. After ball milling, the powder is dried at 100-120° C. for standby use;

S106: adding 15wt% to 25wt% of the dried powder obtained in S105 into a PVA solution as a binder, granulating the powder and performing uniaxial dry pressing at 10 to 20 MPa;

S107: Place the product obtained from S106 into a sintering furnace, heat it to 200°C at a heating rate of 2-5°C/min, keep it warm for 1-4 hours to drain water, then heat it to 400-600°C to drain the binder for 2-6 hours, then heat it to 880-920°C to keep it warm for 2-5 hours, cool it to room temperature with the furnace, and obtain a test sample.

Embodiment 1:

The method for preparing the low-dielectric and low-loss composite LTCC material provided in the embodiment of the present invention comprises the following steps:

Step 1: Prepare analytically pure SrCO ₃ , CuO and SiO ₂ in a molar ratio of SrCO ₃ :CuO:SiO ₂ =1:1:4; then perform ball milling to mix the ingredients evenly; add deionized water and ball milling medium in a mass ratio of 1:2:5 to the ingredients; perform ball milling for 4 hours at a planetary ball mill speed of 250 rpm; and dry the obtained powder at 100°C for later use.

Step 2: Pass the dried powder obtained in step 1 through a 40-mesh sieve, put it into a crucible and compact it, and pre-sinter it at a heating rate of 3°C/min to 950°C, keep it warm for 3 hours, and cool it in the furnace to obtain SrCuSi ₄ O ₁₀ pre-sintered material.

Step 3. Prepare analytically pure Li ₂ CO ₃ , Y ₂ O ₃ and MoO ₃ in a molar ratio of Li ₂ CO ₃ :Y ₂ O ₃ :MoO ₃ =1:1:4; ball-mill the prepared raw materials to mix the ingredients evenly, add deionized water and ball-milling medium in a mass ratio of 1:2:5, and ball-mill for 4 hours at a ball-milling speed of 250 rpm. After ball-milling, dry the obtained powder at 100°C for use.

Step 4: Pass the dried powder obtained in step 3 through a 40-mesh sieve, put it into a crucible and compact it, and pre-sinter it at a heating rate of 3°C/min to 550°C, keep it warm for 3h, and cool it in the furnace to obtain (Li _0.5 Y _0.5 )MoO ₄ pre-sintered material.

Step 5. The SrCuSi ₄ O ₁₀ pre-calcined material and the (Li _0.5 Y _0.5 )MoO ₄ pre-calcined material obtained in step 2 and step 4 are weighed and prepared according to a weight ratio of (100-x)% SrCuSi ₄ O ₁₀ +x% (Li _0.5 Y _0.5 )MoO ₄ (wherein 17≤x≤21), and then deionized water and ball milling medium are added according to a mass ratio of 1:2:5, and the ball milling is performed at a ball milling speed of 250 rpm for 6 hours. After ball milling, the powder is dried at 100°C for standby use.

Step 6: Add 20 wt% of PVA solution as a binder to the dried powder obtained in step 5, granulate it and uniaxially dry press it at 20 MPa.

Step 7: Place the product obtained in step 6 into a sintering furnace, heat it to 200°C at a heating rate of 2°C/min, keep it for 2 hours to drain water, then heat it to 500°C to drain the binder for 3 hours, then heat it to 880-920°C and keep it for 3 hours, cool it to room temperature with the furnace, and obtain a test sample.

Embodiment 2:

SrCO3, CuO, SiO2 are prepared in a molar ratio of SrCO3:CuO:SiO2=1:1:4, and deionized water and ball milling medium are added in a mass ratio of 1:1-2:4-6 according to the prepared ingredients, and the ball milling speed is 250-300rpm, and the ball milling is performed for 4-6 hours. After the ball milling, the obtained powder is dried at 100-120°C for use; the analytically pure Li2CO3, Y2O3 and MoO3 are prepared in a molar ratio of Li2CO 3: Y2O3: MoO3 = 1:1:4, the prepared raw materials are ball-milled once to make the ingredients uniformly mixed, deionized water and ball-milling medium are added according to the ingredients, deionized water and ball-milling medium in a mass ratio of 1:1-2:4-6, and the ball-milling speed is 250-300rpm, and the ball-milling is performed for 4-6h. After ball-milling, the obtained powder is dried at 100-120°C for use; S102 and S104 are used to obtain SrCuSi4O10 pre-sintered material and (Li0.5 Y0.5)MoO4 pre-sintered material is weighed and mixed according to the weight ratio of (100-x)%SrCuSi4O10+x%(Li0.5Y0.5)MoO4 (wherein x=17), and then deionized water and ball milling medium are added according to the weight ratio of 1:1-2:4-6, and the ball milling is performed at a ball milling speed of 250-300rpm for 6-12h. After the ball milling, the powder is dried at 100-120°C for standby use; S 15wt% to 25wt% of PVA solution is added to the dried powder obtained by 105 as a binder, granulated and uniaxially dry pressed at 10 to 20MPa; the product obtained by S106 is put into a sintering furnace, heated to 200℃ at a heating rate of 2 to 5℃/min, kept warm for 1 to 4 hours to drain water, then heated to 400 to 600℃ to drain the binder for 2 to 6 hours, then heated to 880 to 920℃ to keep warm for 2 to 5 hours, cooled to room temperature with the furnace, and obtained a test sample.

Embodiment 3:

SrCO3, CuO, SiO2 are prepared in a molar ratio of SrCO3:CuO:SiO2=1:1:4, and deionized water and ball milling medium are added in a mass ratio of 1:1-2:4-6 according to the prepared ingredients, and the ball milling speed is 250-300rpm, and the ball milling is performed for 4-6 hours. After the ball milling, the obtained powder is dried at 100-120°C for use; the analytically pure Li2CO3, Y2O3 and MoO3 are prepared in a molar ratio of Li2CO 3: Y2O3: MoO3 = 1:1:4, the prepared raw materials are ball-milled once to make the ingredients uniformly mixed, deionized water and ball-milling medium are added according to the ingredients, deionized water and ball-milling medium in a mass ratio of 1:1-2:4-6, and the ball-milling speed is 250-300rpm, and the ball-milling is performed for 4-6h. After ball-milling, the obtained powder is dried at 100-120°C for use; S102 and S104 are used to obtain SrCuSi4O10 pre-sintered material and (Li0.5 Y0.5)MoO4 pre-sintered material is weighed and mixed according to the weight ratio of (100-x)%SrCuSi4O10+x%(Li0.5Y0.5)MoO4 (wherein x=19), and then deionized water and ball milling medium are added according to the weight ratio of 1:1-2:4-6, and the ball milling speed is 250-300rpm for 6-12h. After the ball milling, the powder is dried at 100-120°C for standby use; S 15wt% to 25wt% of PVA solution is added to the dried powder obtained by 105 as a binder, granulated and uniaxially dry pressed at 10 to 20MPa; the product obtained by S106 is put into a sintering furnace, heated to 200℃ at a heating rate of 2 to 5℃/min, kept warm for 1 to 4 hours to drain water, then heated to 400 to 600℃ to drain the binder for 2 to 6 hours, then heated to 880 to 920℃ to keep warm for 2 to 5 hours, cooled to room temperature with the furnace, and obtained a test sample.

Embodiment 4:

SrCO3, CuO, SiO2 are prepared in a molar ratio of SrCO3:CuO:SiO2=1:1:4, and deionized water and ball milling medium are added in a mass ratio of 1:1-2:4-6. The ball milling is performed at a speed of 250-300 rpm for 4-6 hours. After the ball milling, the obtained powder is dried at 100-120°C for use. The analytically pure Li2CO3, Y2O3 and MoO3 are massaged into The raw materials are prepared in a ratio of Li2CO3:Y2O3:MoO3=1:1:4, and the prepared raw materials are ball-milled once to make the ingredients uniformly mixed. Deionized water and ball-milling media are added according to the ingredients and the mass ratio of deionized water and ball-milling media of 1:1-2:4-6, and the ball-milling is carried out at a ball-milling speed of 250-300 rpm for 4-6 hours. After ball-milling, the obtained powder is dried at 100-120°C for use; S102 and S104 are obtained to obtain SrCuSi 4O10 pre-sintered material and (Li0.5Y0.5)MoO4 pre-sintered material are weighed and mixed according to the weight ratio of (100-x)% SrCuSi4O10+x% (Li0.5Y0.5)MoO4 (where x=21), and then deionized water and ball milling medium are added according to the weight ratio of 1:1-2:4-6, and the ball milling speed is 250-300rpm, and the ball milling is carried out for 6-12h. The powder is then dried at 100-120°C for later use; a 15wt%-25wt% PVA solution is added to the dried powder obtained from S105 as a binder, granulated and uniaxially dry pressed at 10-20MPa; the product obtained from S106 is placed in a sintering furnace, heated to 200°C at a heating rate of 2-5°C/min, kept for 1-4 hours to drain, then heated to 400-600°C to drain for 2-6 hours, and then heated to 880

Table 1 shows the ε _r value, Qf value and τ _f value corresponding to different values when sintered at 880-920℃.

It can be seen from the embodiments _that the LTCC material provided by the present invention is obtained by solid phase compounding based _{on SrCuSi4O10} and ( _Li0.5Y0.5 ) _MoO4 ; when sintered at a low temperature near 900°C, it can well take into account many technical requirements of LTCC materials such as low dielectric constant, high Qf value and near-zero _τf , and has good application prospects and value in the fields of LTCC integrated devices and substrates.

Table 1 Dielectric properties of composite LTCC materials corresponding to different sintering temperatures and different x values

The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims (8)

1. A low dielectric and low loss LTCC composite material, characterized in that it is composed of two phases of SrCuSi ₄ O ₁₀ and (Li _0.5 Y _0.5 )MoO ₄ , and when compounding, the weight ratio of the two phases of pre-sintered materials is (100-x)% SrCuSi ₄ O ₁₀ + x% (Li _0.5 Y _0.5 )MoO ₄ , wherein 17≤x≤21; The low-dielectric and low-loss LTCC composite material has a sintering temperature of 880~920°C, ε _r = 7.7~8.1, a Q×f value of 46,000~53,000 GHz, and τ _f = -10~10 ppm/ ºC; The method for preparing the low-dielectric and low-loss LTCC composite material comprises the following steps: Step 1: Prepare analytically pure SrCO ₃ , CuO and SiO ₂ in a molar ratio; then perform ball milling to evenly mix the ingredients; add deionized water and ball milling medium in a mass ratio of 1:1~2:4~6; perform ball milling for 4~6 hours at a planetary ball mill speed of 250~300 rpm; after ball milling, dry the obtained powder at 100~120 ºC for later use; Step 2: sieve the dried powder obtained in step 1, put it into a crucible and compact it, and pre-sinter it at a heating rate of 2-5°C/min to 900-1000°C, keep it warm for 2-4 hours, and cool it with the furnace to obtain _SrCuSi4O10 pre-sintered _material ; Step 3: Prepare analytically pure Li ₂ CO ₃ , Y ₂ O ₃ and MoO ₃ in a molar ratio; ball-mill the prepared raw materials to make the ingredients uniformly mixed, add deionized water and ball-milling medium in a mass ratio of 1:1~2:4~6, ball-mill at a ball-milling speed of 250~300 rpm for 4~6 hours, and dry the obtained powder at 100~120 ºC for use; Step 4: sieve the dried powder obtained in step 3, put it into a crucible and compact it, raise the temperature to 500-600°C for pre-calcination, keep it warm for 2-4 hours, and cool it with the furnace to obtain (Li _0.5 Y _0.5 )MoO ₄ pre-calcined material; Step 5, weigh and mix the SrCuSi ₄ O ₁₀ pre-calcined material and (Li _0.5 Y _0.5 )MoO ₄ pre-calcined material obtained in step 2 and step 4 according to the weight ratio of (100-x)% SrCuSi ₄ O ₁₀ + x% (Li _0.5 Y _0.5 )MoO ₄ , then add deionized water and ball milling medium in a mass ratio of 1:1~2:4~6, ball mill at a ball mill speed of 250~300rpm for 6~12 hours, and after ball milling, dry the powder at 100~120 ºC for use; Step 6: Add 15 wt% to 25 wt% of PVA solution as a binder to the dried powder obtained in step 5, granulate it and perform uniaxial dry pressing at 10 to 20 MPa; Step 7: Place the product obtained in step 6 into a sintering furnace, heat it to 200°C at a heating rate of 2-5°C/min, keep it warm for 1-4 hours to drain water, then heat it to 400-600°C to drain the binder for 2-6 hours, then heat it to 880-920°C to keep it warm for 2-5 hours, cool it to room temperature with the furnace, and obtain a test sample. 2. The low dielectric and low loss LTCC composite material according to claim 1, characterized in that in said step 1, analytically pure SrCO ₃ , CuO and SiO ₂ are mixed in a molar ratio of SrCO ₃ :CuO:SiO ₂ =1:1:4. 3. The low dielectric and low loss LTCC composite material according to claim 1, characterized in that in the step 2, the dried powder obtained in the step 1 is passed through a 40-80 mesh sieve. 4. The low dielectric constant and low loss LTCC composite material according to claim 1, characterized in that in said step _three , analytically pure _Li2CO3 , _Y2O3 and _MoO3 are mixed in a molar ratio of _Li2CO3 : _Y2O3 : _MoO3 = ₁ : ₁ : ₄ . 5. The low dielectric and low loss LTCC composite material according to claim 1, characterized in that, in the step 4, the dried powder obtained in the step 3 is passed through a 40-80 mesh sieve, and after being sieved, it is placed in a crucible for compaction, and the temperature is raised to 500-600 ºC at a heating rate of 2-5 ºC/min for pre-sintering. 6. The low dielectric and low loss LTCC composite material according to claim 1, characterized in that the concentration of the PVA solution in step six is 8-10 wt%. 7. Use of the low-dielectric and low-loss LTCC composite material according to any one of claims 1 to 6 in a LTCC integrated device. 8. Use of the low-dielectric and low-loss LTCC composite material as claimed in any one of claims 1 to 6 in a substrate.