A kind of preparation method of low dielectric constant microwave dielectric ceramic material
Technical field
The present invention uses solid-phase synthesis to prepare low dielectric constant microwave dielectric ceramic material, belongs to green powder technology of preparing in LTCC (LTCC) field.
Background technology
In recent years, low dielectric constant microwave dielectric ceramic material is owing to being used for making polyrod antenna, medium substrate and other related device of microwave communication system and microwave circuit, so be used widely on civilian and military.These application have following requirement to low dielectric constant microwave dielectric ceramic material: the DIELECTRIC CONSTANT ε that (1) is stable
r; (2) low-dielectric loss (being high quality factor Q*f (GHz) value); (3) temperature coefficient of resonance frequency going to zero
τ f , in order to ensure that device has good stability when the temperature fluctuation.These require greatly to have limited stupalith and are applied to practical devices.Most of existing low dielectric LTCC system microwave dielectric material is by borosilicate glass, ceramic packing and provide high-intensity alumina packing to form.But borosilicate glass system contains lead conventionally, under high frequency, can cause dielectric loss to increase, this from environment protection angle, is also not suitable for the development of following electronic material by affecting the wastage rate of stupalith in high-frequency range.The present invention uses borate glass compound a small amount of aluminum oxide and silicon-dioxide again, can allow dielectric loss, high conductivity, the strong mechanical performance of stupalith realize harmony.
Now, international mature is produced and can be provided the company of several porcelain with low dielectric constants to mainly contain tri-of DuPont, Ferro and Heraeus, and domestic still in following the tracks of development, most LTCC products depend on these porcelains of import.The for example MgO-Al of IBM Corporation's research and development
2o
3-SiO
2based material, its specific inductivity is the CaO-B of 5.3~5.7, Ferro company
2o
3-SiO
2based material, its specific inductivity is 901 series materials of 7.0~9.0, DuPont company, its specific inductivity is 5.2~5.9.But along with the modularization of following electronic component and the surplus of electronic terminal product, the competition of Costco Wholesale must be fiercer, the raw material design of domestic manufacturer's original adoption directly will be difficult to meet the requirement of rate war from the way of external packing import.As can be seen here, break away from the dependence to external LTCC porcelain, the process for producing of developing national LTCC porcelain and advanced person is significant for the development of China's electronic material industry.
Summary of the invention
The invention provides a kind of preparation method of low dielectric constant microwave dielectric ceramic material, stupalith provided by the invention has low-k, low-loss and good temperature stability and processing characteristics.Technical problem to be solved by this invention is achieved through the following technical solutions.
A preparation method for low dielectric constant microwave dielectric ceramic material, its technique is as follows:
1) batching, mixing, ball milling
By glass powder precursor material according to Ca (OH)
237.1 ~ 38.4wt%; H
3bO
343.42 ~ 45.70wt%; Li
2cO
33.34 ~ 6.95wt%; La
2o
311.21 ~ 12.53wt% weighs mixing, adds solvent and zirconia ball, adopts wet ball grinding 8 ~ 10 hours;
2) oven dry, melting, fragmentation
Precursor material discharging after step 1) ball milling filters out zirconia ball, in 100 ~ 120 DEG C of oven dry, then at 1475 ± 25 DEG C of melt water quenchings, then crushing grinding to become particle diameter be the glass powder of 200 ~ 300 μ m;
3) composite, the ball milling of porcelain, granulation, compressing tablet, sintering
By step 2) glass powder and the Al that prepare
2o
3according to glass powder 30 ~ 40wt%; Al
2o
35 ~ 10wt%; SiO
245 ~ 60wt% weighs mixing, adds solvent and zirconia ball, adopts wet ball grinding 10 ~ 12 hours; Then add the high polymer binder aqueous solution of 10 ~ 15wt%, ball milling 4 ~ 6 hours, mixes, granulation, compressing tablet, binder removal sintering.
The specific inductivity of described low dielectric constant microwave dielectric ceramic material is 3.5~5.0@1MHz~4GHz, dielectric loss is 0.0010~0.0050@1MHz~4GHz, resonance temperature factor τ f=0~20ppm/oC, insulation resistivity ρ is 2.1 × 1012 Ω cm~4.0 × 1012 Ω cm.
Solvent described in described step 1) is deionized water or dehydrated alcohol.
The weight proportion of glass powder precursor material, solvent, zirconia ball described in described step 1) is 1:1 ~ 2:1 ~ 4.
The weight proportion of mixed powder, solvent, zirconia ball described in described step 3) is 1:1 ~ 2:1 ~ 4.
The high polymer binder aqueous solution adding described in described step 3) is the aqueous solution of polyvinyl butyral acetal (PVB) or polyvinyl alcohol (PVA), and concentration is 10 ~ 15wt%.
Binder removal sintering process described in step 3): the ceramic plate pressing is warmed up to 450 DEG C of insulations 2 hours with the heat-up rate of 2 DEG C/min, be warmed up to again 650 DEG C of insulations 2 hours, be warmed up to 850~900 DEG C of insulation 30min with the heat-up rate of 3 DEG C/min, cool to 400 DEG C with the cooling rate of 3 DEG C/min, cool to room temperature with the furnace.
Compared with prior art, stupalith of the present invention has following advantage:
1. specific inductivity is low, dielectric loss is low, meets high-frequency high-speed requirement;
2. good temperature stability;
3. suitability for secondary processing is superior;
4. raw material is cheap, and preparation technology is simple, and production cost is low, to equipment workshop without particular requirement;
5. Product Green of the present invention, environmental protection, meets the RoHS of European Union instruction, not leaded, cadmium, mercury, sexavalent chrome Cr
6+, the objectionable impurities such as Polybrominated biphenyl PBBs, Poly Brominated Diphenyl Ethers PBDEs, reduced to the full extent the environmental pollution bringing in raw material, waste material and production process.
Embodiment
The present invention further illustrates by the following examples.
embodiment 1
Take 37.1g Ca (OH)
2; 43.42g H
3bO
3; 6.95g Li
2cO
3; 11.21g La
2o
3mix, add 200g deionized water and 400g zirconia ball, adopt wet ball grinding 8 hours;
After glass raw material discharging after ball milling, in 100 DEG C of oven dry, then at 1475 DEG C of melt water quenchings, then crushing grinding to become particle diameter be the glass powder of 200 μ m;
Take glass powder, 10g Al that 60g has prepared
2o
3, 120g SiO
2mix, add 200g deionized water and 400g zirconia ball, adopt wet ball grinding 10 hours; Add the PVA high polymer binder aqueous solution of 38ml 10wt%, ball milling 4 hours, mixes, granulation compression molding; The ceramic plate pressing is warmed up to 450 DEG C of insulations 2 hours with the heat-up rate of 2 DEG C/min in kiln formula sintering oven, then is warmed up to 650 DEG C of insulations 2 hours; Be warmed up to 850 DEG C of insulation 30min with the heat-up rate of 3 DEG C/min, cool to 400 DEG C with the cooling rate of 3 DEG C/min, cool to room temperature with the furnace, obtain low dielectric constant microwave dielectric ceramic material.
embodiment 2
Take 37.5g Ca (OH)
2; 44.5g H
3bO
3; 5.5g Li
2cO
3; 11.5g La
2o
3mix, add 200 g deionized waters and 400g zirconia ball, adopt wet ball grinding 9 hours;
After glass raw material discharging after ball milling, in 110 DEG C of oven dry, then at 1480 DEG C of melt water quenchings, then crushing grinding to become particle diameter be the glass powder of 250 μ m;
Take glass powder, 14g Al that 64g has prepared
2o
3, 120g SiO
2mix, add 360g deionized water and 720g zirconia ball, adopt wet ball grinding 10 hours; Add the PVA high polymer binder aqueous solution of 36ml 12wt%, ball milling 5 hours, mixes, granulation compression molding; The ceramic plate pressing is warmed up to 450 DEG C of insulations 2 hours with the heat-up rate of 2 DEG C/min in kiln formula sintering oven, then is warmed up to 650 DEG C of insulations 2 hours; Be warmed up to 850 DEG C of insulation 30min with the heat-up rate of 3 DEG C/min, cool to 400 DEG C with the cooling rate of 3 DEG C/min, cool to room temperature with the furnace, obtain low dielectric constant microwave dielectric ceramic material.
embodiment 3
Take 38g Ca (OH)
2; 45.2g H
3bO
3; 4.6g Li
2cO
3; 12g La
2o
3mix, add 210g deionized water and 420g zirconia ball, adopt wet ball grinding 9 hours;
After glass raw material discharging after ball milling, in 110 DEG C of oven dry,, then at 1490 DEG C of melt water quenchings, then crushing grinding to become particle diameter be the glass powder of 250 μ m;
Take glass powder, 18g Al that 70g has prepared
2o
3, 100g SiO
2mix, add 200g deionized water and 400g zirconia ball, adopt wet ball grinding 11 hours; Add the PVA high polymer binder aqueous solution of 37.6ml 14wt%, ball milling 6 hours, mixes, granulation compression molding; The ceramic plate pressing is warmed up to 450 DEG C of insulations 2 hours with the heat-up rate of 2 DEG C/min in kiln formula sintering oven, then is warmed up to 650 DEG C of insulations 2 hours; Be warmed up to 900 DEG C of insulation 30min with the heat-up rate of 3 DEG C/min, cool to 400 DEG C with the cooling rate of 3 DEG C/min, cool to room temperature with the furnace, obtain low dielectric constant microwave dielectric ceramic material.
embodiment 4
Take 38.4g Ca (OH)
2; 45.7g H
3bO
3; 3.54g Li
2cO
3; 12.53g La
2o
3mix, add 200g deionized water and 400g zirconia ball, adopt wet ball grinding 10 hours;
After glass raw material discharging after ball milling, in 120 DEG C of oven dry, then at 1500 DEG C of melt water quenchings, then crushing grinding to become particle diameter be the glass powder of 300 μ m;
Take glass powder, 20g Al that 80g has prepared
2o
3, 90g SiO
2mix, add 190g deionized water and 360g zirconia ball, adopt wet ball grinding 12 hours; Add the PVA high polymer binder aqueous solution of 42ml 15wt%, ball milling 6 hours, mixes, granulation compression molding; The ceramic plate pressing is warmed up to 450 DEG C of insulations 2 hours with the heat-up rate of 2 DEG C/min in kiln formula sintering oven, then is warmed up to 650 DEG C of insulations 2 hours; Be warmed up to 900 DEG C of insulation 30min with the heat-up rate of 3 DEG C/min, cool to 400 DEG C with the cooling rate of 3 DEG C/min, cool to room temperature with the furnace, obtain low dielectric constant microwave dielectric ceramic material.
Table 1 embodiment of the present invention test result
As known from Table 1, all samples all can be at the lower sintering of middle low temperature (Ts≤900 DEG C); Specific inductivity 3.5~5.0@1MHz~4GHz of sample, dielectric loss is 0.0010~0.0050@1MHz~4GHz, resonance temperature factor τ
f=0~20ppm/ DEG C, insulation resistivity ρ is 2.1 × 10
12Ω cm~4.0 × 10
12Ω cm.