CN107465395A - A kind of lamination sheet type ceramic RF low pass filter and preparation method thereof - Google Patents

A kind of lamination sheet type ceramic RF low pass filter and preparation method thereof Download PDF

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Publication number
CN107465395A
CN107465395A CN201710536457.8A CN201710536457A CN107465395A CN 107465395 A CN107465395 A CN 107465395A CN 201710536457 A CN201710536457 A CN 201710536457A CN 107465395 A CN107465395 A CN 107465395A
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frequency
ceramic
low pass
filter
sheet type
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Inventor
罗洪梁
刘季超
樊应县
李建辉
林亚梅
徐鹏飞
庞岩
王智会
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Shenzhen Zhenhua Ferrite and Ceramic Electronics Co Ltd
China Zhenhua Group Science and Technology Co Ltd
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Shenzhen Zhenhua Ferrite and Ceramic Electronics Co Ltd
China Zhenhua Group Science and Technology Co Ltd
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Priority to CN201710536457.8A priority Critical patent/CN107465395A/en
Publication of CN107465395A publication Critical patent/CN107465395A/en
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    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H1/00Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network
    • H03H1/0007Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network of radio frequency interference filters
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/62218Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining ceramic films, e.g. by using temporary supports
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/638Removal thereof
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01Frequency selective two-port networks
    • H03H7/0115Frequency selective two-port networks comprising only inductors and capacitors
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H1/00Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network
    • H03H2001/0021Constructional details
    • H03H2001/0085Multilayer, e.g. LTCC, HTCC, green sheets

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Power Engineering (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
  • Filters And Equalizers (AREA)

Abstract

The invention discloses a kind of lamination sheet type ceramic RF low pass filter and preparation method thereof, low pass filter includes four and draws termination electrode and internal circuit, electrode is followed successively by input anode, output head anode and two common ground ends, and internal circuit includes multiple built-in capacitances and the interior electrode of multiple built-in inductance compositions on the three dimensions in different medium layer;Inductance is vertical three-dimensional helical structure;The dielectric layer of inductance and electric capacity uses the ceramic material of high-frequency low-consumption.Median filter dielectric material of the present invention is using high-frequency ceramic material, capacity, the sensibility reciprocal of inner member can realize minor adjustments, and it is easier to realize monolithic structure, mature preparation process, uniformity is well suitably produced in batches, therefore, the wave filter has the advantages that cut-off frequency is high, operating frequency range is wide, Out-of-band rejection is high, rectangular degree is good, reliability is high, radio band is good using uniformity.

Description

A kind of lamination sheet type ceramic RF low pass filter and preparation method thereof
Technical field
The invention belongs to wave filter technology field, more particularly, to a kind of lamination sheet type ceramic RF low pass filter And preparation method thereof.
Background technology
Wave filter is a kind of to the selective two-port network of frequency, and it all plays non-always in the communications industry Often important role.
Lamination sheet type radio frequency low pass filter is a kind of Novel Filter, with the development of mechanics of communication, its working frequency Scope is more and more wider, frequency of use also more and more higher, miniaturization, the trend clearly (production in some fields of high frequency development Product frequency of use has reached 40GHz, even more high).The appearance of mobile communication technology of new generation and the need of new-type weapon and equipment Ask, make the market demand for the small size lamination sheet type radio-frequency filter that working band scope is wide, frequency of use is high (up to tens GHz) Amount is swift and violent to be increased.
Lamination sheet type ceramic RF (microwave) wave filter is folded by electron ceramic material casting molding processes, high accuracy prints Layer the various technical processes such as technology and low-temperature sintering technology and manufactured high frequency filter.Its spy such as have small volume, Insertion Loss low Property, it is widely used in microwave communication, radar navigation, electronic countermeasure, satellite communication, VHF/UHF emitter/receivers, humorous It is indispensable important devices in microwave system in the systems such as ripple suppressor, digital-to-analogue converter and test instrumentation, its performance Quality often directly affects the performance indications of whole communication system.
At present, develop and produce small size lamination sheet type low pass filter and mainly use two ways:Pure inductance or pure electricity The unit piece form and LC structure types of appearance type, and its technology maturation is unit piece form, but this kind of small size lamination sheet type Wave filter be based on low cut-off frequency, it is and not high with Out-of-band rejection performance, the features such as rectangular degree difference.
Although traditional LC structure types wave filter using area it is small production and its inband flatness it is fine, penetrating The uniformity used of frequency range is poor, while also is difficult to produce in batches.
At present, more ripe lamination sheet type wave filter largely uses " double electric capacity+mono- inductance " or " single capacitor+bis- The simple π types such as inductance ", T-type structure, the wave filter inband flatness and Out-of-band rejection characteristic so designed is preferable, still Cut-off frequency is relatively low, causes its frequency of use to be limited, it is difficult to develops to high frequency direction.
In addition, the low pass filter for the lamination multilayer ceramic structure announced is constantly present some deficiencies, such as prior art 1 It is Publication No. CN1578129, the patent application document of entitled " a kind of multilayer sheet type ceramics low pass filter ", wherein Low pass filter uses planar spiral inductor structure, in the wave filter of small size microwave section, the introducing of the inductance of this kind of structure Parasitic capacitance is very big on frequency characteristic influence, and as its volume is smaller, its influence degree is more and more deeper.
Prior art 2 is Publication No. CN101404485A, entitled " a kind of lamination sheet type wave filter and its preparation The patent application document of method ", its median filter using ferrite with it is ceramic co-fired by the way of prepare, though with small size, band It is outer to suppress the advantages that big, rectangular degree is big, working frequency is wide, but cut-off frequency is relatively low, and the reliability of wave filter is poor The problems such as.The reason for poor reliability:Special-shaped material is not easy to match between ferrite and ceramic material.It is more severe especially with environment During quarter, the stress between special section is inevitably generated, and is easily caused interiors of products and slight crack occurs, and then has influence on its use.
The Publication No. CN10216396A of prior art 3, entitled " a kind of multilayer chip filter and its preparation side The patent application document of method ", wherein wave filter is prepared by way of the punching injection Ferrite Material in ceramic medium material, Cause use can though alleviating the dissimilar materials matching that patent publication No. is CN101404485A median filters to a certain extent The problem of by property, but still can not avoid completely, still suffer from the hidden danger of test reliability.
The content of the invention
The defects of for prior art, the invention provides a kind of lamination sheet type ceramic RF low pass filter, the filtering The cut-off frequency of device is high, operating frequency range is wide, Out-of-band rejection is high, rectangular degree is good, reliability is high, radio band uses uniformity It is good.
The invention provides a kind of lamination sheet type ceramic RF low pass filter, has four extraction termination electrodes, including defeated Enter proper pole (16), output head anode (15) and two common ground ends (14), the lamination sheet type ceramic RF LPF The internal circuit of device includes multiple built-in capacitances (17) and multiple built-in inductance (10) on the three dimensions in different medium layer The interior electrode (13) of composition;The inductance (10) is vertical three-dimensional helical structure;The inductance (10) and the electric capacity (17) Dielectric layer uses ceramic material.
Present invention also offers a kind of preparation method of lamination sheet type ceramic RF low pass filter, comprise the steps:
(1) casting slurry will be obtained after ceramic powder, organic solvent, plasticizer, binding agent and dispersant;And by institute State after casting slurry carries out ball milling and curtain coating processing and form the diaphragm that thickness is 5 microns~100 microns;Wherein ceramic powder, have Solvent, plasticizer, the mass percent of binding agent and dispersant are followed successively by (40~60) wt%, (40~60) wt%, (1.0 ~4.0) wt%, (4.5~8.5) wt%, (0.09~0.5) wt%;
(2) diaphragm is punched according to the needs connected between inductance and electric capacity, the needs connected between inductance, Filling perforation, then conductor printing, lamination, pressing, isostatic pressed processing are carried out successively;
(3) chip-type filter ceramic chips carry out dumping and sintering processes after isostatic pressed is handled;Sintering temperature be 800 DEG C~ 950℃;
(4) the chip-type filter ceramic chips after sintering are carried out successively forming lamination sheet type after applying silver, end-blocking, termination processing Ceramic RF low pass filter.
Using high-frequency ceramic material, capacity, the sensibility reciprocal of inner member can be realized micro- filter medium material of the present invention Minor adjustment, and be easier to realize monolithic structure, mature preparation process, uniformity is well suitably produced in batches, therefore, the wave filter With cut-off frequency is high, operating frequency range is wide, Out-of-band rejection is high, rectangular degree is good, reliability is high, radio band is good using uniformity The advantages that.
Brief description of the drawings
Fig. 1 is the equivalent circuit of lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention, wherein Fig. 1 (a) it is a kind of LC equivalent circuit structures, Fig. 1 (b) is another LC equivalent circuit structures;
Fig. 2 (a) is the composition structural representation of lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention;
Fig. 2 (b) is the top view of lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention;
Fig. 3 is that the internal electrode composition structure of lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention is shown It is intended to;(front view)
Fig. 4 is induction structure schematic diagram in lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention;(just View)
Fig. 5 is capacitance structure schematic diagram in lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention;(just View)
Fig. 6 be lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention preparation method in lamination sheet type Wave filter middle side edge applies silver-colored structural representation;
Fig. 7 is that the insertion loss characteristic curve of lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention shows It is intended to;
Fig. 8 is the laminated sheet that cut-off frequency provided in an embodiment of the present invention is respectively 4850MHz, 7600MHz and 9100MHz The damage curve schematic diagram of formula ceramic RF low pass filter;
Fig. 9 is cut-off frequency 30800MHz provided in an embodiment of the present invention lamination sheet type ceramic RF low pass filter Damage curve schematic diagram;
Wherein, 13 be interior electrode, and 14 be common ground end, and 15 be output head anode, and 16 be input anode, and 10 be electricity Sense, 11 be electrode connection points, and 17 be electric capacity, and 21 be wave filter, and 22 be terminal electrode paste, and 23 be the silver-colored roller of painting.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and It is not used in the restriction present invention.
Lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention can apply to harmonic shutter, VHF/ In the devices such as radio frequency suppression or digital-to-analogue converter in UHF transmitter/receiver, DC circuit plate;Microwave can also be applied to The fields such as communication, radar navigation, electronic countermeasure, satellite communication.
For problem above, the invention provides a kind of novel laminated chip ceramic RF low pass filter and its preparation side Method.Filter medium material of the present invention can realize small tune using high-frequency ceramic material, capacity, the sensibility reciprocal of inner member Section, and be easier to realize monolithic structure, mature preparation process, uniformity is well suitably produced in batches, and therefore, the wave filter has Cut-off frequency height (radio frequency), operating frequency range is wide, Out-of-band rejection is high, rectangular degree is good, reliability is high, radio band uses uniformity The advantages that good.Meanwhile the preparation technology of wave filter of the present invention and the technique and LTCC of conventional chip components and parts (LTCC) technique is mutually compatible, it is not necessary to more addition other equipments again.
The wave filter of the present invention uses LC structure types (equivalent circuit Fig. 1), and internal built-up circuit is not mainly by Formed with multiple built-in capacitances 17 on the three dimensions of dielectric layer and multiple built-in inductance 10 (see Fig. 2, Fig. 3, wherein Fig. 3 only For one kind in filter construction of the present invention, 7) exponent number of its wave filter is.The present invention is by adjusting each inductance value and each electric capacity Ratio (further contemplating parasitic parameter certainly) between amount, and by three-dimensional space high density, it is highly integrated will be more Individual electric capacity 17 carries out ingenious layout with multiple inductance 10, (carries out authentic analog simulation by electromagnetic field simulation software, adjusts inductance 10th, the electrode shape of electric capacity 17, structure dislocation between the two etc., reduces " ghost effect " of stray inductance and parasitic capacitance, It is fitted the influence that a variety of associated couplings between each inner member be present), the rf filtering of different performance parameter request can be achieved Device designs.By adjusting internal capacitance, the number of inductance (and corresponding proportioning), the setting of different filter orders is realized, is tied Close the cleverly layout of 3 D stereo circuit connection structure, the adjustable range of the achievable cut-off frequency of the present invention:30MHz~ 40000MHz。
Filter internal inductance 10 of the present invention is reduced and posted using vertical three-dimensional helical structure (being structure known in this field) Raw electric capacity.Under identical effective inductance value, the element of vertical spin structure inductance 10 has higher than planar spiral-type structure Self-resonant frequency (SRF) and quality factor (Q), and be advantageous to reduce the size of device.Due to the general capacity of radio-frequency filter Smaller, built-in capacitance 17 can be achieved the goal using conventional metals-dielectric-metal form capacity plate antenna structure.
In addition, the dielectric layer of inductance 10 and electric capacity 17 uses the ceramic material of high-frequency low-consumption, avoid completely due to different Integrity problem caused by material mismatches, greatly improve the reliability of product.
In embodiments of the present invention, according to the requirement of wave filter technology index, based on compatible principle of electromagnetism, with reference to LTCC technology, structure design is carried out to radio frequency low pass filter using electromagnetic simulation software HFSS.
The common engineering step of radio-frequency filter design:
First, achievable approximating function is found using approximation theory;
Secondly, the amplitude square function using approximating function as wave filter;
Then, its attenuation function is drawn by the amplitude square function of wave filter;
Subsequently, combination technology index (insertion-loss method is mainly by nominal frequency and cut-off frequency parameter index) is true Determine the exponent number of wave filter, normalized is carried out to lowpass prototype filter, obtain L, C initial parameter value of each element;
When transmission function (approximating function) using Butterworth function as wave filter, filter approximating letter of the invention Number, by the series of computation to its amplitude square function, derive, it is as follows to obtain its insertion attenuation function:
Wherein, ωcFor cut-off frequency.By filter parameter technical indicator parameter " nominal frequency (1dB dot frequencies), cut-off Frequency (3dB dot frequencies) " substitutes into above derivation formula, you can the preliminary exponent number for finding wave filter.
After the parameter value that the exponent number of wave filter, built-in inductance 10, electric capacity 17 are extrapolated by theory, 3 D electromagnetic field is utilized Simulation software HFSS radio-frequency filters are emulated.Binding isotherm result of calculation and the situation of emulation, carry out optimization design repeatedly, Complete product design.
Finally, device inner electrode and product three-dimensional structure (using three dimensional wiring technology) design, design are filtered During thermal design and reliability design are taken into account.
By Design and optimization and the checking repeatedly of experiment, the perfect structure of wave filter of the present invention is finally given.
Lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention is singly-terminal pair, has four exits Electrode, including two termination electrodes (representing input anode 16, output head anode 15 respectively) and two central electrode (common grounds End is 14), specific as shown in Fig. 2 (b).
The internal circuit of the lamination sheet type ceramic RF low pass filter of the present invention, including by three in different medium layer (see Fig. 2, Fig. 3, wherein Fig. 3 is only the interior electrode 13 that multiple built-in capacitances 17 on dimension space form with multiple built-in inductance 10 One kind in filter construction of the present invention, the exponent number of its wave filter is 7), inductance 10 is identical with the dielectric material of electric capacity 17, adopts With the ceramic material of high-frequency low-consumption.
Inductance 10 and the layout type 1 of electric capacity 17:Dielectric layer includes stacking gradually the upper laminated portions of arrangement, the first isolation Layer, intermediate laminate part, the second separation layer and lower laminated portions, by some circles, (number of turns as needed may be used for intermediate laminate part Adjust) four inductance 10 are composed in series, input anode 16 and output head anode 15 are drawn out to respectively.Upper laminated portions and lower stacking Part includes the lamination sheet type electric capacity 17 made of ceramic material of the same race, and using parallel, each electric capacity 17 is:One Terminate at the tie point of two series connection inductance 10 (penetrated by way of " punching/filling electrode " inductance 10 and electric capacity 17 it Between separation layer realize connection), or be connected to the input anode 16 or output head anode 15, other end ground connection.Inductance Separated between 10 and electric capacity 17 using relatively thick high-frequency ceramic dielectric layer, it is therefore an objective to reduce between inductance 10 and electric capacity 17 Coupling, interference.
Inductance 10 and the layout type 2 of electric capacity 17:Dielectric layer include stacking gradually the upper laminated portions of arrangement, separation layer and Lower laminated portions, upper laminated portions include multiple inductance 10 being connected in series, and lower laminated portions include multiple described respectively Electric capacity 17, one end of each electric capacity 17 pass through the separation layer, and are connected to the tie point that two inductance 10 dock, each institute State the other end ground connection of electric capacity 17.Electric capacity 17 penetrated by way of " punching or filling electrode " separation layer realize with inductance 10 it Between connection.The similar layout type 1 of connected mode between inductance 10 and electric capacity 17.
Inductance 10 and the layout type 3 of electric capacity 17:Output head anode 15 is more with being distributed with respectively in the input anode 16 The inductance 10 of individual arranged in series, multiple electric capacity 17 are distributed with common ground end 14, one end of electric capacity 17 is connected to two institutes The tie point of the docking of inductance 10 is stated, the other end of the electric capacity 17 is grounded, and the connected mode between inductance 10 and electric capacity 17 is similar Layout type 1.
Wherein, (see Fig. 4, wherein Fig. 4 is only one kind in filter construction of the present invention to the built-in electrode of inductance 10, and it is filtered The exponent number of device is the 7) wiring on three dimensions, makes axial symmetry of its electrode relative to horizontal, longitudinally central line.
The electrode of built-in capacitance 17 is also similar, and (see Fig. 5, wherein Fig. 5 is only in filter construction of the present invention with inductance 10 One kind, the exponent number of its wave filter for 7), using make its electrode relative to laterally, the axisymmetric mode of longitudinally central line.
This way it is secured that moved towards in inductance 10 and electric capacity 17 in the electrode of input anode 16, output head anode 15 Crash consistency, input anode 16, output head anode 15 can be exchanged completely, easy to install.
After the completion of the structure design of wave filter and technological design, on LTCC production lines, by slurry preparation, it is cast, cuts Cut, punch, conductor layer printing, lamination, isostatic pressed, cutting, dumping, sintering, Tu Yin, silver ink firing, plating, the processing step such as test, Carry out radio frequency low pass filter product development.
The specific implementation flow of the preparation method of lamination sheet type ceramic RF low pass filter provided in an embodiment of the present invention Comprise the following steps:
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.First, the tangent value of the dielectric loss angle of high-frequency ceramic material is necessarily less than or equal to 6*10-4.Secondly, radio-frequency filter Interior electrode should not use silver-palladium inner electrode slurry, therefore, the sintering temperature of ceramic material will be less than less than 900 DEG C.Then, it is situated between The range of choice of electric constant is:3~100.
The optimum condition of dielectric constant:The wave filter that cut-off frequency is less than 460MHz is prepared, dielectric constant is 20~50 Material is advisable;460~1300MHz's of cut-off frequency, dielectric constant is advisable in 10~20 material;Cut-off frequency 1300~ 3600MHz's, dielectric constant is advisable in 6~10 material;More than cut-off frequency 3600MHz, from dielectric constant below 6 Material it is more satisfactory.
Certainly, can the ceramic material be selected, it is also necessary to which investigating performance parameter has:The dielectric strength of material, capacitance temperature Coefficient, its matching with silver paste, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design, it is therefore an objective to casting slurry made of making is uniformly dispersed, not reunited, stability is good, while ensure its in folded film bubble-free, Easy demoulding, easy bonding, ductility are moderate etc..
The casting slurry of table 1 matches
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to the needs of design diaphragm, the ceramics green ceramic diaphragm of required thickness is cast out in casting machine, diaphragm thickness is micro- 5~100 Rice is adjustable.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Porcelain green diaphragm carries out the printing for tying positive electrode and grounding electrode of built-in capacitance, and the thickness control for printing silver paste is micro- 5~12 Within the scope of rice.
Step 6:Lamination, pressing.The ceramics green ceramic that the ceramics green ceramic diaphragm for printing electrode and part are not printed electrode Diaphragm carries out lamination, pressing according to the structure designed by the present invention.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressing process Parameter Conditions are carried out in press:20~40MPa of pressure, 50~90 DEG C of temperature, 5~30Min of pressurize.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 200 DEG C~500 DEG C.Dumping process has to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Serious influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, again Metallization pattern may be made to come off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 800~950 DEG C of the sintering temperature of this product.Sintering mechanism is complex in sintering process, How to ensure the contraction of Metal slurry and strip degree of the same race is the key of sintering process, and its technological parameter mainly has heating speed Rate, heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as occur in LTCC wave filter samples small The phenomenon that hole " is heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
Wave filter silver ink firing follower head silver layer of the present invention can influence whether plating plating with glass phase caused by impurity or silver ink firing Layer effect, product is first carried out to the residue of surface treatment removal product surface before plating.Then, will according to the coating of product Ask, select suitable electroplating technical conditionses to be electroplated on plating line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
For further description wave filter provided by the invention and preparation method thereof, it is described in detail such as in conjunction with instantiation Under:
Embodiment 1~3:It is 145MHz, 350MHz, 459MHz radio frequency low pass filter to prepare cut-off frequency respectively
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.The tangent value of the dielectric loss angle of high-frequency ceramic material is selected to be less than 6*10-4, the sintering temperature of ceramic material is 860 ℃。
Dielectric constant selection situation is as shown in table 2 corresponding to three embodiments.
The dielectric constant selection scheme table of table 2
Embodiment 1 2 3
Cut-off frequency (MHz) 145 350 430
Material dielectric constant 50 36 20
Certainly, ceramic material property parameter is also investigated:The dielectric strength of material, capacitance temperature factor, its with silver paste With property, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design.
The casting slurry of table 3 matches
Raw material Ceramic powder Organic solvent Plasticizer Binding agent Dispersant
Ratio (wt%) 45.0 45.0 3.8 6.1 0.1
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to design diaphragm needs, casting machine be cast out needed for thickness ceramics green ceramic diaphragm, diaphragm thickness at 35 microns, Control errors are in ± 0.5 micron.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Ceramic dielectric film carries out knot positive electrode and the printing of grounding electrode of built-in capacitance, prints the thickness control of silver paste at 6 ± 0.5 microns Within the scope of.
Step 6:Lamination, pressing.By the ceramics green ceramic diaphragm for printing electrode and the diaphragm that does not print electrode of part according to Structure designed by the present invention, carry out lamination, pressing.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressed preferred parameter are carried out in press:Pressure 18MPa, temperature 70 C, pressurize 30Min.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 430 DEG C.Dumping process has seriously to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, may make again Metallization pattern comes off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 860 DEG C or so of the sintering temperature of this product.Sintering mechanism is complex in sintering process, How to ensure the contraction of Metal slurry and strip degree of the same race is the key of sintering process, and its technological parameter mainly has heating speed Rate, heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as occur in LTCC wave filter samples small The phenomenon that hole " is heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
After product silver ink firing in step 10, required according to the coating of product, select suitable electroplating technical conditionses electroplating Electroplated on line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
The insertion loss figure for the wave filter that test cut-off frequency is 350MHz is shown in Fig. 7.
Embodiment 4~6:It is respectively 460MHz, 700MHz, 1200MHz radio frequency low pass filter to prepare cut-off frequency
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.The tangent value of the dielectric loss angle of high-frequency ceramic material is selected to be less than 6*10-4, the sintering temperature of ceramic material is 880 ℃。
Dielectric constant selection situation is as shown in table 4 corresponding to three embodiments.
The dielectric constant selection scheme table of table 4
Embodiment 4 5 6
Cut-off frequency (MHz) 460 700 1200
Material dielectric constant 18 16.7 13.3
Certainly, ceramic material property parameter is also investigated:The dielectric strength of material, capacitance temperature factor, its with silver paste With property, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design.
The casting slurry of table 5 matches
Raw material Ceramic powder Organic solvent Plasticizer Binding agent Dispersant
Ratio (wt%) 48.0 43.3 2.5 6.1 0.1
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to design diaphragm needs, casting machine be cast out needed for thickness ceramics green ceramic diaphragm, diaphragm thickness at 30 microns, Control errors are in ± 0.5 micron.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Ceramic dielectric film carries out knot positive electrode and the printing of grounding electrode of built-in capacitance, prints the thickness control of silver paste at 7 ± 0.5 microns Within the scope of.
Step 6:Lamination, pressing.By the ceramics green ceramic diaphragm for printing electrode and the diaphragm that does not print electrode of part according to Structure designed by the present invention, carry out lamination, pressing.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressed preferred parameter are carried out in press:Pressure 20MPa, 65 DEG C of temperature, pressurize 25Min.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 500 DEG C.Dumping process has seriously to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, may make again Metallization pattern comes off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 880 DEG C or so of the sintering temperature of this product.Sintering mechanism is complex in sintering process, How to ensure the contraction of Metal slurry and strip degree of the same race is the key of sintering process, and its technological parameter mainly has heating speed Rate, heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as occur in LTCC wave filter samples small The phenomenon that hole " is heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
After product silver ink firing in step 10, required according to the coating of product, select suitable electroplating technical conditionses electroplating Electroplated on line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
The insertion loss figure for the wave filter that test cut-off frequency is 700MHz is shown in Fig. 7.
Embodiment 3:It is 1750MHz radio frequency low pass filters to prepare cut-off frequency
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.The tangent value of the dielectric loss angle of high-frequency ceramic material is selected to be less than 6*10-4, the sintering temperature of ceramic material is 880 ℃。
The dielectric constant selection scheme table of table 6
Embodiment 7 8 9
Cut-off frequency (MHz) 1300 1750 3500
Material dielectric constant 9.8 8.5 6.3
Certainly, ceramic material property parameter is also investigated:The dielectric strength of material, capacitance temperature factor, its with silver paste With property, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design.
The casting slurry of table 7 matches
Raw material Ceramic powder Organic solvent Plasticizer Binding agent Dispersant
Ratio (wt%) 48.0 43.3 2.4 6.2 0.1
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to design diaphragm needs, casting machine be cast out needed for thickness ceramics green ceramic diaphragm, diaphragm thickness at 30 microns, Control errors are in ± 0.5 micron.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Ceramic dielectric film carries out knot positive electrode and the printing of grounding electrode of built-in capacitance, prints the thickness control of silver paste at 8 ± 0.5 microns Within the scope of.
Step 6:Lamination, pressing.By the ceramics green ceramic diaphragm for printing electrode and the diaphragm that does not print electrode of part according to Structure designed by the present invention, carry out lamination, pressing.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressed preferred parameter are carried out in press:Pressure 28MPa, temperature 70 C, pressurize 18Min.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 450 DEG C.Dumping process has seriously to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, may make again Metallization pattern comes off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 880 DEG C or so of the sintering temperature of this product.Sintering mechanism is complex in sintering process, How to ensure the contraction of Metal slurry and strip degree of the same race is the key of sintering process, and its technological parameter mainly has heating speed Rate, heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as occur in LTCC wave filter samples small The phenomenon that hole " is heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
After product silver ink firing in step 10, required according to the coating of product, select suitable electroplating technical conditionses electroplating Electroplated on line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
The insertion loss figure for the wave filter that test cut-off frequency is 1750MHz is shown in Fig. 7.
Embodiment 10~11:It is 3600MHz, 4850MHz radio frequency low pass filter to prepare cut-off frequency respectively
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.The tangent value of the dielectric loss angle of high-frequency ceramic material is selected to be less than 6*10-4, the sintering temperature of ceramic material is 900 ℃。
In terms of the selection of dielectric constant, the cut-off frequency of wave filter is respectively 3600MHz, 4850MHz wave filter, choosing The dielectric constant for the dielectric material selected is respectively 5.7,4.3.
Certainly, ceramic material property parameter is also investigated:The dielectric strength of material, capacitance temperature factor, its with silver paste With property, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design.
The casting slurry of table 8 matches
Raw material Ceramic powder Organic solvent Plasticizer Binding agent Dispersant
Ratio (wt%) 48.3 43.1 2.3 6.2 0.1
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to design diaphragm needs, casting machine be cast out needed for thickness ceramics green ceramic diaphragm, diaphragm thickness at 25 microns, Control errors are in ± 0.5 micron.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Ceramic dielectric film carries out knot positive electrode and the printing of grounding electrode of built-in capacitance, prints the thickness control of silver paste at 8 ± 0.5 microns Within the scope of.
Step 6:Lamination, pressing.By the ceramics green ceramic diaphragm for printing electrode and the diaphragm that does not print electrode of part according to Structure designed by the present invention, carry out lamination, pressing.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressed preferred parameter are carried out in press:Pressure 30MPa, temperature 60 C, pressurize 10Min.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 460 DEG C.Dumping process has seriously to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, may make again Metallization pattern comes off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 900 DEG C or so of the sintering temperature of this product.Sintering mechanism is complex in sintering process, How to ensure the contraction of Metal slurry and strip degree of the same race is the key of sintering process, and its technological parameter mainly has heating speed Rate, heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as occur in LTCC wave filter samples small The phenomenon that hole " is heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
After product silver ink firing in step 10, required according to the coating of product, select suitable electroplating technical conditionses electroplating Electroplated on line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
The insertion loss figure for the wave filter that test cut-off frequency is 4850MHz is shown in Fig. 8.
Embodiment 12:It is 7600MHz radio frequency low pass filters to prepare cut-off frequency
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.The tangent value of the dielectric loss angle of high-frequency ceramic material is selected to be less than 6*10-4, the sintering temperature of ceramic material is 900 ℃。
In terms of the selection of dielectric constant, the cut-off frequency of wave filter is 7600MHz wave filter, and cut-off frequency exists More than 3600MHz, dielectric constant of dielectric material of selection is 4.0 at this.
Certainly, ceramic material property parameter is also investigated:The dielectric strength of material, capacitance temperature factor, its with silver paste With property, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design.
The casting slurry of table 9 matches
Raw material Ceramic powder Organic solvent Plasticizer Binding agent Dispersant
Ratio (wt%) 47.9 43.2 2.6 6.2 0.1
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to design diaphragm needs, casting machine be cast out needed for thickness ceramics green ceramic diaphragm, diaphragm thickness at 35 microns, Control errors are in ± 0.5 micron.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Ceramic dielectric film carries out knot positive electrode and the printing of grounding electrode of built-in capacitance, prints the thickness control of silver paste in 8 ± 1 microns of models Within enclosing.
Step 6:Lamination, pressing.By the ceramics green ceramic diaphragm for printing electrode and the diaphragm that does not print electrode of part according to Structure designed by the present invention, carry out lamination, pressing.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressed preferred parameter are carried out in press:Pressure 25MPa, temperature 60 C, pressurize 18Min.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 450 DEG C.Dumping process has seriously to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, may make again Metallization pattern comes off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 900 DEG C or so of the sintering temperature of this product.Sintering mechanism is complex in sintering process, How to ensure the contraction of Metal slurry and strip degree of the same race is the key of sintering process, and its technological parameter mainly has heating speed Rate, heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as occur in LTCC wave filter samples small The phenomenon that hole " is heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
After product silver ink firing in step 10, required according to the coating of product, select suitable electroplating technical conditionses electroplating Electroplated on line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
The insertion loss figure for testing the wave filter is shown in Fig. 8.
Embodiment 13:It is 9100MHz radio frequency low pass filters to prepare cut-off frequency
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.The tangent value of the dielectric loss angle of high-frequency ceramic material is selected to be less than 6*10-4, the sintering temperature of ceramic material is 900 ℃。
In terms of the selection of dielectric constant, the cut-off frequency of wave filter is 9100MHz wave filter, and cut-off frequency exists More than 3600MHz, dielectric constant of dielectric material of selection is 3.7 at this.
Certainly, ceramic material property parameter is also investigated:The dielectric strength of material, capacitance temperature factor, its with silver paste With property, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design.
The casting slurry of table 10 matches
Raw material Ceramic powder Organic solvent Plasticizer Binding agent Dispersant
Ratio (wt%) 47.9 43.2 2.5 6.3 0.1
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to design diaphragm needs, casting machine be cast out needed for thickness ceramics green ceramic diaphragm, diaphragm thickness at 35 microns, Control errors are in ± 0.5 micron.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Ceramic dielectric film carries out knot positive electrode and the printing of grounding electrode of built-in capacitance, prints the thickness control of silver paste in 8 ± 1 microns of models Within enclosing.
Step 6:Lamination, pressing.By the ceramics green ceramic diaphragm for printing electrode and the diaphragm that does not print electrode of part according to Structure designed by the present invention, carry out lamination, pressing.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressed preferred parameter are carried out in press:Pressure 20MPa, temperature 60 C, pressurize 20Min.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 450 DEG C.Dumping process has seriously to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, may make again Metallization pattern comes off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 900 DEG C or so of the sintering temperature of this product.Sintering mechanism is complex in sintering process, How to ensure the contraction of Metal slurry and strip degree of the same race is the key of sintering process, and its technological parameter mainly has heating speed Rate, heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as occur in LTCC wave filter samples small The phenomenon that hole " is heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
After product silver ink firing in step 10, required according to the coating of product, select suitable electroplating technical conditionses electroplating Electroplated on line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
The insertion loss figure for testing the wave filter is shown in Fig. 8.
Embodiment 14:It is 30800MHz radio frequency low pass filters to prepare cut-off frequency
Step 1:The selection of high-frequency ceramic material.According to the needs of filter performance parameters, suitable high-frequency ceramic is selected Material.The tangent value of the dielectric loss angle of high-frequency ceramic material is selected to be less than 6*10-4, the sintering temperature of ceramic material is 890 ℃。
In terms of the selection of dielectric constant, the cut-off frequency of wave filter is 30800MHz wave filter, and cut-off frequency exists More than 3600MHz, dielectric constant of dielectric material of selection is 3.5 at this.
Certainly, ceramic material property parameter is also investigated:The dielectric strength of material, capacitance temperature factor, its with silver paste With property, its frequency of use etc. etc..
Step 2:Prepare casting slurry.It is suitable according to the ratio surface of selected ceramic powder particle and electrically charged characteristic, selection Solvent system (including organic solvent, plasticizer, binding agent and dispersant), then carry out the ratio optimization of each organic additive Design.
The casting slurry of table 11 matches
Raw material Ceramic powder Organic solvent Plasticizer Binding agent Dispersant
Ratio (wt%) 47.9 43.2 2.5 6.3 0.1
Step 3:Ball milling, curtain coating.The casting slurry that step 2 is prepared, by select appropriate ball-milling technology slurrying it Afterwards, according to design diaphragm needs, casting machine be cast out needed for thickness ceramics green ceramic diaphragm, diaphragm thickness at 45 microns, Control errors are in ± 0.5 micron.
Step 4:Punching, filling perforation.Part ceramics green ceramic diaphragm obtained by step 3 connect according between inductance and electric capacity The needs connect, connected between inductance are punched.Then filling perforation is carried out using silver paste.
Step 5:Conductor printing.Inductor conductor printing is carried out with the ceramics green ceramic diaphragm of filling perforation, with the pottery partly not punched Ceramic dielectric film carries out knot positive electrode and the printing of grounding electrode of built-in capacitance, prints the thickness control of silver paste in 8 ± 1 microns of models Within enclosing.
Step 6:Lamination, pressing.By the ceramics green ceramic diaphragm for printing electrode and the diaphragm that does not print electrode of part according to Structure designed by the present invention, carry out lamination, pressing.
Step 7:Isostatic pressed.The chip-type filter ceramic chips for completing lamination are mounted in the hermetic bag that vacuumizes be placed in etc. it is quiet Isostatic pressed, isostatic pressed preferred parameter are carried out in press:Pressure 20MPa, temperature 60 C, pressurize 20Min.
Step 8:Dumping.Dumping process be organic bond gasification and burn off process, and sintering before must through process, Its temperature is located at 450 DEG C.Dumping process has seriously to the quality of low temperature co-fired type radio-frequency filter (LTCC radio-frequency filters) Influence, if dumping is insufficient, polylayer forest will bubble, deforms or be layered after sintering;If dumping is excessive, may make again Metallization pattern comes off.Therefore to strictly to be controlled during dumping, the especially assurance to heating rate.
Step 9:After dumping is completed, sintering process is put into, sintering is under certain atmospheric condition, allows LTCC products to exist The process being densified under hot conditions, 890 DEG C of the sintering temperature of this product.Sintering mechanism is complex in sintering process how The contraction for ensureing Metal slurry and strip degree of the same race is the key of sintering process, its technological parameter mainly have the rate of heat addition, Heat time, soaking time, temperature fall time etc., these are required for strictly controlling.Such as there is aperture in LTCC wave filter samples The phenomenon " heaved " outward, and as caused by the different degrees of contraction of Metal slurry and strip.
Step 10:Tu Yin, end-blocking.It is middle side edge to apply silver-colored position, and end-blocking position is the two ends of product, as three in Fig. 2 Shown in view, black portions are electrode.The radio-frequency filter of the present invention has 4 exits, and middle termination electrode applies silver using rolling (see Fig. 6), both sides termination electrode are carried out using the end-blocking mode for gluing silver.The painting silver of middle termination electrode is that wave filter of the present invention is prepared in fact One of existing difficult point, it is necessary to silver wheel is applied to design according to shape of product and size, to ensure the appearance and size of termination electrode and thickness The precision of degree.
Step 11:Termination is handled.
After product silver ink firing in step 10, required according to the coating of product, select suitable electroplating technical conditionses electroplating Electroplated on line.
After the completion of plating, it is possible to obtain lamination sheet type ceramic RF low pass filter of the present invention.
The insertion loss figure for testing the wave filter is shown in Fig. 9.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to The limitation present invention, all any modification, equivalent and improvement made within the spirit and principles of the invention etc., all should be included Within protection scope of the present invention.

Claims (4)

1. a kind of preparation method of lamination sheet type ceramic RF low pass filter, it is characterised in that comprise the steps:
(1) casting slurry will be obtained after ceramic powder, organic solvent, plasticizer, binding agent and dispersant;And by the stream Prolong after slurry carries out ball milling and curtain coating processing and form the diaphragm that thickness is 5 microns~100 microns;Wherein ceramic powder, You Jirong Agent, plasticizer, the mass percent of binding agent and dispersant be followed successively by (40~60) wt%, (40~60) wt%, (1.0~ 4.0) wt%, (4.5~8.5) wt%, (0.09~0.5) wt%;
(2) diaphragm is punched according to the needs connected between inductance and electric capacity, the needs connected between inductance, filled out Hole, then conductor printing, lamination, pressing, isostatic pressed processing are carried out successively;
(3) chip-type filter ceramic chips carry out dumping and sintering processes after isostatic pressed is handled;Sintering temperature is 800 DEG C~950 ℃;
(4) the chip-type filter ceramic chips after sintering are carried out successively forming lamination sheet type ceramics after applying silver, end-blocking, termination processing Radio frequency low pass filter.
2. preparation method as claimed in claim 1, it is characterised in that in step (1), the medium of the ceramic powder material The tangent value of loss angle is less than or equal to 6*10-4, for sintering temperature less than 900 DEG C, dielectric constant is 3~100.
3. the preparation method as described in claim any one of 1-2, it is characterised in that the lamination sheet type ceramic RF low pass filtered The cut-off frequency of ripple device is lower, and the dielectric constant of the ceramic powder is higher.
4. preparation method as claimed in claim 3, it is characterised in that in step (1), be less than when needing to prepare cut-off frequency During 460MHz lamination sheet type ceramic RF low pass filter, use dielectric constant for 20~50 ceramic powder;When needing to make When standby cut-off frequency is 460~1300MHz lamination sheet type ceramic RF low pass filter, dielectric constant is used as 10~20 Ceramic powder;When needing to prepare the lamination sheet type ceramic RF low pass filter that cut-off frequency is 1300~3600MHz, use Ceramic powder of the dielectric constant 6~10;When the lamination sheet type ceramic RF low pass for needing to prepare cut-off frequency and being more than 3600MHz During wave filter, using ceramic powder of the dielectric constant below 6.
CN201710536457.8A 2014-04-03 2014-04-03 A kind of lamination sheet type ceramic RF low pass filter and preparation method thereof Pending CN107465395A (en)

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Application publication date: 20171212