A SrCuSi4O 10 Low dielectric loss composite LTCC material and preparation method thereof

Abstract

The application belongs to the field of electronic ceramic materials and its manufacturing, in particular to a SrCuSi4O 10 -based low-dielectric and low-loss composite LTCC material and its preparation method. 10 The SrCuSi4O 10 -based low-dielectric and low-loss composite LTCC material is composed of SrCuSi4O 10 and vanadate two phases, and is prepared by directly composite sintering of SrCuSi4O 10 and vanadate two kinds of pre-sintering materials for inorganic chemical field and optical field by solid phase method, with sintering temperature of 900-950 DEG C, epsilon r =8.6-9.1, Qxf value 23000-32600 GHz, tau f =-10-10 ppm / DEG C; the vanadate is Sr3V2O8 or Ba3V2O8. The application simultaneously meets many advantages of the LTCC material such as ultra-low dielectric, low loss and near-zero temperature coefficient, directly composites without additional sintering aids, has low cost and is easy to be applied in industrialization, and has good application prospect in the LTCC integrated device and substrate.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of electronic ceramic materials and its manufacturing, and particularly relates to a SrCuSi4O 10 Base low-dielectric low-loss composite LTCC material and preparation method thereof, which has low dielectric constant (ε r <10), low loss and near-zero resonance frequency temperature coefficient (-10≤τ f ≤+10 ppm / ºC). BACKGROUND

[0002] LTCC (low temperature co-fired ceramic) technology is the most important passive integrated and active / passive hybrid integrated technology at present, and has a very wide application in contemporary electronic system. The core of the LTCC technology includes three parts, which are LTCC process technology, LTCC design technology and LTCC material technology.

[0003] Among them, the LTCC material technology is the most critical. In the LTCC substrate and high-frequency application LTCC components, the LTCC material generally required to be used has a low dielectric constant (ε r <10), which helps to reduce the delay time of information transmission; a low dielectric loss (high Qf value), which helps to reduce the loss caused by the medium in the device or substrate and a resonance frequency temperature coefficient τ f which helps to reduce the influence of temperature change on the performance of the LTCC device and substrate.

[0004] At present, there are many researches on low-dielectric LTCC materials at home and abroad. According to the comprehensive research results, silicate system ceramics have the advantages of low dielectric and low loss. Typical silicate LTCC material systems include Mg2SiO4, Zn2SiO4, Li2MgSiO4, CaMgSi2O6, BaCuSi4O 10 , SrCuSi4O 10 and the like with different ion substitutions. Among these silicates, the SrCuSi4O 10 material has obvious advantages, which not only has a low sintering temperature (1100℃), a low dielectric constant (5.5~6) and a high Qf value (the Qf value of SrCuSi4O 10 can be about 50000 GHz) and the like. However, the material needs to be added with various fluxes to be sintered at a low temperature below 950℃ required by the LTCC process. Meanwhile, the material also has a large negative resonance frequency temperature coefficient, so other ways are needed to adjust the resonance frequency temperature coefficient.

[0005] The temperature coefficient is usually adjusted by compounding with positive temperature coefficient materials such as CaTiO3 and TiO2. However, these positive temperature coefficient materials have high dielectric loss and high dielectric constant, and high sintering temperature. After compounding, it is more difficult to sinter at low temperature, and more flux dopants are needed to achieve low-temperature sintering. Moreover, the Qf value of the material system is significantly reduced, the dielectric constant is significantly increased, and the advantages of low-dielectric materials are difficult to realize. SUMMARY

[0006] In view of the above problems or deficiencies, in order to solve the problem that the existing SrCuSi4O 10 The LTCC technology of the material is difficult to realize low-dielectric, low-loss and near-zero temperature coefficient, and the present application provides a SrCuSi4O 10 low-dielectric low-loss composite LTCC material and a preparation method thereof. The present application adopts a method of directly compounding and sintering SrCuSi4O 10 with a vanadate system (Sr3V2O8 or Ba3V2O8) of inorganic materials to realize low-temperature sintering and adjust the temperature coefficient of the resonant frequency. At the same time, the dielectric constant and dielectric loss of the composite material are also low, meeting the requirements of ultra-low-dielectric and low-loss. The composite material can be sintered at a low temperature below 950 ºC without adding any flux, and the temperature coefficient of the resonant frequency of the material can be adjusted to within ±10 ppm / ºC. The dielectric constant of the material is between 8.6 and 9.1, and the Qf value is more than 22000 GHz. The composite material has a good application prospect in LTCC integrated devices and substrates.

[0007] A SrCuSi4O 10 low-dielectric low-loss composite LTCC material is composed of SrCuSi4O 10 and a vanadate, and the weight ratio is (100-x)% SrCuSi4O 10 + x% Sr3V2O8 / Ba3V2O8. SrCuSi4O 10 and the vanadate are directly compounded and sintered by a solid phase method, wherein 45≤x≤55, the sintering temperature is 900-950℃, ε r = 8.6-9.1, Qxf value is 23000-32600 GHz, τ f = -10-10 ppm / ºC. The vanadate is Sr3V2O8 or Ba3V2O8.

[0008] The preparation method of the above-mentioned SrCuSi4O 10 low-dielectric low-loss composite LTCC material is as follows:

[0009] Step 1, prepare SrCuSi4O10 pre-sintered material and vanadate pre-sintered material;

[0010] SrCuSi4O 10 Pre-sintered material:

[0011] Analytically pure SrCO3, CuO and SiO2 were weighed according to the molar ratio SrCO3:CuO:SiO2=1:1:4, and then ball-milled to mix the ingredients uniformly. Deionized water and ball-milling medium were added according to the mass ratio of 1:1~3:4~6, and the planetary ball mill was operated at a rotation speed of 250~300 rpm for 4~6 h. After ball-milling, the obtained powder was dried at 100~120 °C and sieved through a mesh (80~120 mesh). The sieved powder was pre-sintered at a temperature of 900~1000 °C at a heating rate of 3~5 °C / min, and then cooled in the furnace to obtain SrCuSi4O 10 Pre-sintered material.

[0012] Vanadate pre-sintered material:

[0013] Analytically pure SrCO3(or BaCO3) and V2O5 were weighed according to the molar ratio SrCO3(or BaCO3):V2O5=3:1, and then ball-milled to mix the ingredients uniformly. Deionized water and ball-milling medium were added according to the mass ratio of 1:1~3:4~6, and the planetary ball mill was operated at a rotation speed of 250~300 rpm for 4~6 h. After ball-milling, the obtained powder was dried at 100~120 °C and sieved through a mesh (80~120 mesh). The sieved powder was pre-sintered at a temperature of 800~900 °C at a heating rate of 3~5 °C / min, and then cooled in the furnace to obtain Sr3V2O8 or Ba3V2O8 pre-sintered material.

[0014] Step 2, the SrCuSi4O 10 Pre-sintered material and vanadate (Sr3V2O8 or Ba3V2O8) pre-sintered material were weighed according to the weight ratio of (100-x)% SrCuSi4O 10 +x% Sr3V2O8 / Ba3V2O8 (wherein 45≤x≤55), and then deionized water and ball-milling medium were added according to the mass ratio of 1:1~3:4~6. The planetary ball mill was operated at a rotation speed of 250~300 rpm for 6~12 h. After ball-milling, the powder was dried at 100~120 °C for standby use.

[0015] Step 3, the dried powder obtained in Step 2 was first sieved through a mesh (80~120 mesh), and then added into a PVA solution (concentration of 15wt%~25wt%) as a binder. After grinding uniformly, the powder was granulated and uniaxially dry-pressed to form a green body.

[0016] Step 4, the product obtained in step 3 is put into a sintering furnace, after degassing, the temperature is raised to 900-950 DEG C for sintering, and then the furnace is cooled to room temperature, to obtain SrCuSi4O 10 Base low die low loss composite LTCC material.

[0017] The SrCuSi4O 10 Base LTCC material provided by the application is obtained by directly sintering the appropriate amount of SrCuSi4O 10 pre-sintered material and Sr3V2O8 / Ba3V2O8 pre-sintered material in a certain proportion. The application is based on the following considerations: first, Sr3V2O8 / Ba3V2O8 material is an inorganic material widely used in recent years, which shows excellent activity and selectivity in some catalytic reactions; and the alkaline earth vanadate has high thermal stability, high crystallinity and high visible light transmittance; so that the vanadate Sr3V2O8 / Ba3V2O8 is widely used and popularized in the field of inorganic chemical industry and the field of optics. However, the application finds and utilizes the temperature-dependent dielectric properties of Sr3V2O8 / Ba3V2O8, which indicates that it may have applications in frequency and temperature sensitive electronic devices. Through further research, it is found that the dielectric constant of the two materials is not high, and the dielectric loss is also low, but it has a very large positive resonance frequency temperature coefficient τ f ≈60 ppm / ºC, which initiatively composites the SrCuSi4O 10 ceramics, which adjusts the resonance frequency temperature coefficient without making the dielectric constant of the composite material too high, and the dielectric loss of the composite material can also be maintained at a very low level; secondly, the densification temperature of Sr3V2O8 / Ba3V2O8 is relatively low, and sintering below 850 DEG C can realize densification. It is found that when the proportion 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 phases can realize low-temperature sintering densification at about 950 DEG C, so it is not necessary to add other low-melting fluxes to promote the low-temperature sintering of the material system, and therefore it is more conducive to improving the comprehensive dielectric properties of the material, and the adjustment of the temperature coefficient and the realization of the low-temperature sintering can be realized at the same time in our composite range. In addition, the two phases do not react with each other to form a new phase when they are compounded, so it is also helpful to obtain excellent microwave dielectric properties. Finally, neither of the two ceramics contains expensive raw materials, so it is also conducive to reducing the research and development cost of the material, and is more suitable for mass production.

[0018] In summary, the SrCuSi4O 10The low-dielectric composite LTCC material has the advantages of ultra-low dielectric, low loss and near-zero temperature coefficient, does not need additional sintering aids for direct compounding, has low cost and is easy to be industrialized, and has good application prospect in LTCC integrated devices and substrates. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A preparation process flow chart of the composite LTCC material of the application.

[0020] Figure 2 An XRD chart of the two-phase composite of the example. DETAILED DESCRIPTION

[0021] The application will be further described in detail below with reference to the embodiments and the accompanying drawings.

[0022] A SrCuSi4O 10 The preparation method of the low-dielectric composite LTCC material (as shown in Figure 1 The specific steps are as follows:

[0023] Step 1, prepare SrCuSi4O 10 Pre-sintered material and vanadate pre-sintered material;

[0024] SrCuSi4O 10 Pre-sintered material:

[0025] Analyzed pure SrCO3, CuO and SiO2 are prepared according to the molar ratio of SrCO3:CuO:SiO2=1:1:4, then the prepared material is ball milled once to make the mixture uniform, deionized water and ball milling medium are added according to the mass ratio of 1:3:5, the planetary ball mill is rotated at 300 rpm for 6 h, after ball milling, the obtained powder is dried at 100ºC and sieved through a 120 mesh screen, then put into an alumina crucible, pre-sintered at 950ºC at a heating rate of 4ºC / min, and kept for 4 h, and cooled in the furnace to obtain SrCuSi4O 10 Pre-sintered material.

[0026] Vanadate pre-sintered material:

[0027] The analytical pure SrCO3 (or BaCO3) and V2O5 are prepared according to the molar ratio of SrCO3:V2O5 = 3:1, the prepared raw materials are ball milled once to make the preparation uniform, deionized water and ball milling medium are added according to the mass ratio of 1:3:5, the ball milling speed is 300 rpm, and the ball milling time is 6 h; after ball milling, the obtained powder is dried at 100ºC and then sieved through a 120 mesh sieve, and then placed in an alumina crucible, heated to 850ºC at a heating rate of 4ºC / min for pre-sintering, and then cooled in the furnace to obtain Sr3V2O8 / Ba3V2O8 pre-sintered material.

[0028] Step 2, the SrCuSi4O 10 The pre-sintered material and the vanadate (Sr3V2O8 or Ba3V2O8) pre-sintered material are weighed and prepared according to the weight ratio of (100-x)% SrCuSi4O 10 + x% Sr3V2O8 / Ba3V2O8 (45≤x≤55), and then deionized water and ball milling medium are added according to the mass ratio of 1:3:5, the ball milling speed is 300 rpm, and the ball milling time is 12 h; after ball milling, the powder is dried at 100ºC for standby use.

[0029] Step 3, the dried powder obtained in step 2 is first sieved through a 120 mesh sieve, and then added to a PVA solution (concentration 15 wt%) as a binder, ground uniformly, granulated and uniaxially dry pressed.

[0030] Step 4, the product obtained in step 3 is placed in a sintering furnace, heated to 200ºC at a heating rate of 2ºC / min, and then cooled in the furnace to room temperature to obtain SrCuSi4O 10 The test sample of the SrCuSi4O

[0031] Figure 2 The XRD patterns of the two-phase composite of the two groups of examples show that the two phases do not react with each other to form a new phase when they are compounded.

[0032] Table 1 shows the ε x The SrCuSi4O 10 The ε r The Qf value and τ f value of the SrCuSi4O

[0033] Table 1:

[0034] x value Sintering temperature (°C) dielectric constant (ε r ) Qf (GHz) Resonant frequency temperature coefficient τ f (ppm / ºC) 45 925 8.81 28700 -8 45 950 8.84 31400 -6 45 975 8.94 32100 -6 50 925 8.95 29540 -1 50 950 9.10 32600 -5 50 975 9.10 31020 -3 55 925 8.98 27100 7 55 950 9.06 27900 8 55 975 9.04 26560 8

[0035] Table 2 is the composite Ba3V2O8 when sintering at 900~950 ºC, each embodiment x Take different values corresponding to SrCuSi4O 10 The ɛ r Value, Qf value and τ f Value of the low-dielectric low-loss composite LTCC material.

[0036] Table 2:

[0037] x value Sintering temperature (°C) dielectric constant (ε r ) Qf (GHz) Resonant frequency temperature coefficient τ f (ppm / ºC) 45 900 8.61 23500 -8 45 925 8.64 26100 -7 45 950 8.74 27100 -2 50 900 8.75 24830 -1 50 925 8.81 27270 1 50 950 8.82 25020 4 55 900 8.78 24770 5 55 925 8.86 23600 6 55 950 8.84 22360 8

[0038] From the above two groups of examples, the SrCuSi4O 10 Based low-dielectric low-loss composite LTCC material provided by the application, based on SrCuSi4O 10 Auxiliary vanadate (Sr3V2O8 or Ba3V2O8) in the field of optics is weight ratio (100-x)%SrCuSi4O 10 + x%Sr3V2O8 / Ba3V2O8, which is obtained by directly sintering two phases by solid phase method; when sintering at low temperature near 925~950ºC, the technical requirements of many LTCC materials such as low dielectric, high Qf value and near zero τ f Can be well considered; solve the problem of low temperature sintering and adjusting the temperature coefficient of resonance frequency of SrCuSi4O 10 Based ceramic material, and the dielectric constant and dielectric loss of the composite material are also very low, which meets the requirements of ultra-low dielectric and low loss, and the cost is low and easy to industrialize, which has good application prospect and value in the field of LTCC integrated devices and substrates.

Claims

1. A SrCuSi40 10 based low dielectric low loss composite LTCC material, characterized in that: SrCuSi4O 10 and vanadate two-phase, the weight ratio (100-x) % SrCuSi4O 10 +x % Sr3V2O8 / Ba3V2O8 two kinds of pre-sintered material with solid phase method directly composite sintering, wherein 45≤x≤55, sintering temperature 900-950 ℃, ε r =8.6-9.1, Qxf value 23000-32600 GHz, τ f =-10-10 ppm / ℃; the vanadate is Sr3V2O8 or Ba3V2O8.

2. The SrCuSi4O 10 The application relates to a preparation method of a low-dielectric-loss composite LTCC material, characterized by comprising the following steps: The specific steps are as follows: Step 1, prepare SrCuSi4O 10 Calcining material and vanadate calcining material SrCuSi4O 10 Pre-burn material: The analytical pure SrCO3, CuO and SiO2 are proportioned according to the molar ratio of SrCO3:CuO:SiO2=1:1:4; then the proportioning is ball-milled to mix uniformly, deionized water and ball-milling medium are added according to the mass ratio of 1:1-3:4-6, and the planetary ball mill is operated at the rotation speed of 250-300 rpm for 4-6 h; after the ball-milling, the obtained powder is dried at 100-120 ℃ and sieved, and then the sieved powder is pre-fired at 900-1000 ℃ with the temperature increasing rate of 3-5 ℃ / min, and the temperature is kept for 3-5 h, and the pre-fired material is obtained after the furnace cooling. 10 Pre-fired material Vanadate pre-sintering material: The analytical pure SrCO3 / BaCO3 and V2O5 are proportioned according to the molar ratio SrCO3 / BaCO3:V2O5=3:1, the prepared raw materials are ball milled to mix uniformly, deionized water and ball milling medium are added according to the mass ratio of 1:1-3:4-6, the ball milling speed is 250-300 rpm, the ball milling time is 4-6 h, the obtained powder is dried at 100-120 ℃ and sieved, the sieved powder is pre-sintered at 800-900 ℃ with the temperature rising rate of 3-5 ℃ / min, the temperature is kept for 3-5 h, and Sr3V2O8 or Ba3V2O8 pre-sintering material is obtained by cooling in the furnace; Step 2, the SrCuSi4O 10 The pre-burning material and the vanadate pre-burning material are weighed according to the weight ratio of (100-x) % SrCuSi4O 10 +x % Sr3V2O8 / Ba3V2O8, then deionized water and ball milling medium are added in a mass ratio of 1:1-3:4-6, ball milling is carried out at a ball milling speed of 250-300 rpm for 6-12 h, and after ball milling, the powder is dried at 100-120 °C for standby use. Step 3, the dried powder obtained in step 2 is sieved first, then added into PVA solution as a binder, and then granulated and single-axis dry-pressed after grinding uniformly; Step 4, the product obtained in step 3 is put into a sintering furnace, after degassing, the temperature is raised to 900-950℃ for sintering, and then the furnace is cooled to room temperature, to obtain SrCuSi4O 10 low dielectric loss composite LTCC material.

3. The SrCuSi4O 10 The application relates to a preparation method of a low-dielectric-loss composite LTCC material. The mesh number of the sieve is 80-120.

4. The SrCuSi4O 10 The application relates to a preparation method of a low-dielectric-loss composite LTCC material, characterized by comprising the following steps: The concentration of the PVA solution is 15wt%-25wt%.

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