Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
  • H03H7/01—Frequency selective two-port networks
  • H03H7/0115—Frequency selective two-port networks comprising only inductors and capacitors
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H1/00—Constructional details of impedance networks whose electrical mode of operation is not specified or applicable to more than one type of network
  • H03H2001/0021—Constructional details
  • H03H2001/0085—Multilayer, e.g. LTCC, HTCC, green sheets

Definitions

• the invention belongs to the technical field of filters, and more particularly to a laminated chip ceramic RF low-pass filter and a preparation method thereof.
• the filter is a two-port network that is selective for frequency and has always played a very important role in the communications industry.
• the laminated chip RF low-pass filter is a new type of filter.
• its operating frequency range is wider and wider, the frequency of use is also higher and higher, and the trend of miniaturization and high frequency development is very high. Obvious (some areas of product use frequency has reached 40GHz, or even higher).
• the emergence of a new generation of mobile communication technologies and the demand for new types of weaponry have led to a rapid increase in the market demand for small-sized laminated chip RF filters with a wide operating frequency range and high frequency of use (up to several tens of GHz).
• the laminated chip ceramic radio frequency (microwave) filter is a high frequency filter made by various processes such as electronic ceramic material casting molding process, high precision printing lamination technology and low temperature sintering technology. It has small size and low insertion loss, and is widely used in microwave communication, radar navigation, electronic countermeasures, satellite communication, VHF/UHF transmitter/receiver, harmonic suppressor, digital-to-analog converter and test instrument. In the system, it is an indispensable important device in the microwave system, and its performance often directly affects the performance index of the entire communication system.
• small-sized laminated chip low-pass filters mainly adopt two methods: pure inductance or pure capacitance type of unit parts and LC structure form, and the technology matures in the form of unit parts, but this kind of small Dimensional laminated chip filters are mainly based on low cutoff frequency, and have the characteristics of low out-of-band rejection and poor squareness.
• the conventional LC structural form filter is small in area production and has good in-band flatness, the consistency in the use of the RF section is poor, and it is also difficult to mass-produce.
• the disclosed low-pass filter of the stacked multilayer ceramic structure always has some disadvantages, as in the prior art 1 is disclosed as CN1578129, and the invention is entitled "a multilayer chip ceramic low-pass filter"
• the patent application file wherein the low-pass filter adopts a planar spiral inductor structure, and in the filter of the small-volume microwave segment, the introduction of the parasitic capacitance of the inductance of the structure has a great influence on the frequency characteristic, and as the volume thereof is smaller, Its influence is getting deeper and deeper.
• the prior art 2 is a patent application file with the publication number CN101404485A, the invention name is "a laminated chip filter and a preparation method thereof", wherein the filter is prepared by co-firing ferrite and ceramic, although it has a small
• Reasons for poor reliability Shaped materials between ferrite and ceramic materials are not easily matched. Especially when the use environment is harsh, the stress between the profiled materials is inevitably generated, which may cause cracks inside the product, which may affect its use.
• Prior Art No. 3 discloses CN10216396A, and the patent name of the invention is "a multilayer chip filter and a preparation method thereof", wherein a filter is prepared by injecting a ferrite material into a ceramic dielectric material.
• the present invention provides a laminated chip ceramic RF low-pass filter having a high cutoff frequency, a wide operating frequency range, high out-of-band rejection, good rectangularity, and high reliability.
• the RF segment is used consistently.
• the present invention provides a laminated chip ceramic RF low-pass filter having four terminals, including an input positive electrode (16), an output positive electrode (15), and two common ground terminals (14).
• the internal circuit of the laminated chip ceramic RF low-pass filter comprises an internal electrode (13) composed of a plurality of built-in capacitors (17) and a plurality of built-in inductors (10) in a three-dimensional space of different dielectric layers; the inductor (10) Is a vertical three-dimensional spiral structure; the dielectric layer of the inductor (10) and the capacitor (17) is made of a ceramic material.
• the invention also provides a method for preparing a laminated chip ceramic RF low-pass filter, comprising the following steps:
• the chip filter raw ceramic sheet is subjected to debinding and sintering treatment; the sintering temperature is 800 ° C to 950 ° C;
• the sintered chip filter ceramic plate is sequentially coated with silver, capped, and terminated to form a laminated chip ceramic RF low-pass filter.
• the filter medium material of the invention adopts a high-frequency ceramic material, and the capacity and the inductance of the internal components can be slightly adjusted, and the monolith structure is relatively easy to be realized, the preparation process is mature, and the consistency is good for mass production, therefore, the filter It has the advantages of high cutoff frequency, wide operating frequency range, high out-of-band rejection, good rectangularity, high reliability, and good consistency of RF segment usage.
• FIG. 1 is an equivalent circuit of a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention, wherein FIG. 1(a) is an LC equivalent circuit structure, and FIG. 1(b) is another LC device. Effective circuit structure;
• FIG. 2(a) is a schematic structural diagram of a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention
• 2(b) is a top plan view of a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention
• FIG 3 is a schematic structural diagram of internal electrodes of a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention. (front view)
• FIG. 4 is a schematic diagram of an inductor structure in a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention. (front view)
• FIG. 5 is a schematic diagram of a capacitor structure in a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention. (front view)
• FIG. 6 is a schematic view showing a silver-plated structure in a middle side of a laminated chip filter in a method for preparing a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention
• FIG. 7 is a schematic diagram showing an insertion loss characteristic curve of a laminated chip ceramic RF low-pass filter according to an embodiment of the present invention.
• FIG. 8 is a cutoff frequency provided by an embodiment of the present invention, which is 4850 MHz and 7600, respectively.
• FIG. 9 is a schematic diagram of a loss curve of a multilayer chip ceramic RF low-pass filter with a cutoff frequency of 30800 MHz according to an embodiment of the present invention.
• 13 is the internal electrode
• 14 is the common ground terminal
• 15 is the output positive pole
• 16 is the input positive pole
• 10 is the inductor
• 11 is the electrode connection point
• 17 is the capacitor
• 21 is the filter
• 22 is the terminal electrode paste
• 23 is a silver coated roller.
• the laminated chip ceramic RF low-pass filter provided by the embodiment of the invention can be applied to devices such as a harmonic suppressor, a VHF/UHF transmitter/receiver, a DC suppression or a digital-to-analog converter in a DC circuit board; Can be applied to microwave communications, radar navigation, electronic countermeasures, satellite communications and other fields.
• the present invention provides a novel laminated chip ceramic RF low-pass filter and a preparation method thereof.
• the filter medium material of the invention adopts a high-frequency ceramic material, and the capacity and the inductance of the internal components can be slightly adjusted, and the monolith structure is relatively easy to be realized, the preparation process is mature, and the consistency is good for mass production, therefore, the filter It has the advantages of high cutoff frequency (RF), wide operating frequency range, high out-of-band rejection, good rectangularity, high reliability, and good consistency of RF segment usage.
• the preparation process of the filter of the invention is compatible with the process of the conventional chip component and the low temperature co-fired ceramic (LTCC) process, and no additional equipment needs to be added.
• LTCC low temperature co-fired ceramic
• the filter of the present invention adopts an LC structure form (equivalent circuit is shown in FIG. 1), and the internal component circuit is mainly composed of a plurality of built-in capacitors 17 in a three-dimensional space of different dielectric layers and a plurality of built-in inductors 10 (see FIG. 2, FIG. 3, wherein FIG. 3 is only one of the filter structures of the present invention, and the order of the filter is 7).
• the present invention adjusts the ratio between each inductance and each capacitance (of course, also considers parasitic parameters), and intelligently arranges a plurality of capacitors 17 and a plurality of inductors 10 by high density and high integration in a three-dimensional space.
• the internal inductance 10 of the filter of the present invention employs a vertical three-dimensional spiral structure (which is well known in the art) to reduce parasitic capacitance.
• the vertical spiral structure inductance 10 element has a higher self-resonant frequency (SRF) and quality factor (Q) than the planar spiral structure, and is advantageous for reducing the size of the device. Since the RF filter generally has a small capacity, the built-in capacitor 17 can achieve the purpose by using a conventional metal-medium-metal form plate capacitor structure.
• the dielectric layer of the inductor 10 and the capacitor 17 adopts a high-frequency low-loss ceramic material, completely avoiding the reliability problem caused by the mismatch of the heterogeneous materials, and greatly improving the reliability of the product.
• the electromagnetic simulation software HFSS is used to design the RF low-pass filter.
• the approximation function is used as the amplitude square function of the filter
• the attenuation function is obtained by the amplitude square function of the filter
• the low-pass prototype filter is denormalized to obtain the initial L, C of each component Parameter value
• the filter approximation function of the present invention obtains its insertion attenuation function by a series of calculations and derivations of its amplitude squared function as follows:
• ⁇ c is the cutoff frequency.
• the simulation is performed using a three-dimensional electromagnetic field simulation software HFSS RF filter. Combined with the theoretical calculation results and the simulation situation, the design is repeated and optimized.
• the internal electrode structure of the filter and the three-dimensional structure of the product are designed, and the thermal design and reliability design are taken into account in the design process.
• the laminated chip ceramic RF low-pass filter provided by the embodiment of the invention is a two-terminal network having four terminal electrodes, including two terminal electrodes (representing the input terminal positive electrode 16, the output terminal positive electrode 15 respectively) and two centers.
• the electrode (common ground 14) is shown in Figure 2(b).
• the internal circuit of the laminated chip ceramic RF low-pass filter of the present invention comprises an internal electrode 13 composed of a plurality of built-in capacitors 17 and a plurality of built-in inductors 10 in three-dimensional space of different dielectric layers (see FIG. 2, FIG. 3, wherein FIG. 3 is only one of the filter structures of the present invention, the order of the filter is 7), and the inductance 10 is the same as the dielectric material of the capacitor 17, and both are high frequency and low loss ceramic materials.
• the inductor 10 and the capacitor 17 are arranged in a mode 1: the dielectric layer includes an upper laminated portion, a first isolation layer, an intermediate laminated portion, a second isolation layer, and a lower laminated portion which are sequentially stacked, and the intermediate laminated portion is composed of a plurality of turns (the number of turns is based on It needs to be adjustable.
• the four inductors 10 are composed in series and are respectively led out to the positive terminal 16 of the input terminal and the positive electrode 15 of the output terminal.
• the upper laminated portion and the lower laminated portion comprise a laminated chip capacitor 17 made of the same kind of ceramic material, which is connected in parallel, each capacitor 17 is: one end is connected at the connection point of the two series of inductors 10 (by " The way of puncturing/filling the electrode is connected through the isolation layer between the inductor 10 and the capacitor 17, or is connected to the positive terminal 16 of the input terminal or the positive terminal 15 of the output terminal, and the other end is grounded.
• the inductor 10 and the capacitor 17 are separated by a relatively thick high-frequency ceramic dielectric layer for the purpose of reducing coupling and interference between the inductor 10 and the capacitor 17.
• the inductor 10 and the capacitor 17 are arranged in a manner 2: the dielectric layer includes an upper laminated portion, an isolation layer, and a lower laminated portion which are sequentially stacked, the upper laminated portion includes a plurality of inductors 10 connected in series, and the lower stacked portions respectively include a plurality of the above-mentioned A capacitor 17, one end of each of the capacitors 17 passes through the isolation layer, and is connected to a connection point where the two inductors 10 are butted, and the other end of each of the capacitors 17 is grounded.
• the capacitor 17 penetrates the isolation layer by means of "puncturing or filling the electrode" to achieve a connection with the inductor 10.
• the connection between the inductor 10 and the capacitor 17 is similar to the layout mode 1.
• the inductor 10 and the capacitor 17 are arranged in a manner 3: a plurality of inductors 10 arranged in series are arranged in the positive pole 15 of the output terminal and the positive pole 16 of the input terminal respectively, and a plurality of the capacitors 17 are distributed in the common ground terminal 14 , and one end of the capacitor 17 Connected to the connection point where the two inductors 10 are butted, the other end of the capacitor 17 is grounded, and the connection between the inductor 10 and the capacitor 17 is similar to the layout mode 1.
• the built-in inductor 10 electrode (see FIG. 4, wherein FIG. 4 is only one of the filter structures of the present invention, the order of the filter is 7), the wiring in three-dimensional space, the electrode is opposite to the horizontal and vertical directions
• the axis of the center is axisymmetric.
• the electrode of the built-in capacitor 17 is similar to the inductor 10 (see Fig. 5, wherein Fig. 5 is only one of the filter structures of the present invention, the order of the filter is 7), and the electrode is made to face the horizontal and vertical directions. The axisymmetric way of the centerline.
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters. First, the tangent of the dielectric loss angle of the high frequency ceramic material must be less than or equal to 6*10 -4 . Secondly, the internal electrode of the RF filter is not suitable for the silver-palladium internal electrode paste. Therefore, the sintering temperature of the ceramic material is lower than 900 °C. Then, the dielectric constant can be selected from the range of 3 to 100.
• materials with a dielectric constant of 6 to 10 at 1300 to 3600 MHz materials with a dielectric constant of 6 or less are preferable for a cutoff frequency of 3600 MHz or more.
• the ceramic material can be selected or not, it is also necessary to examine the performance parameters: the dielectric strength of the material, the temperature coefficient of the capacitor, the matching with the silver paste, the frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvents, plasticizers, binders and dispersants
• the prepared casting slurry has uniform dispersion, no agglomeration and good stability, and at the same time ensures that it has no bubbles, easy to release film, easy to bond, and moderate ductility when laminating.
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast in the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 5 ⁇ 100 microns adjustable.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing. Inductive conductor printing is carried out with a hole-filled ceramic green porcelain diaphragm, and a non-perforated ceramic green ceramic diaphragm is used for printing the junction positive electrode and the ground electrode of the built-in capacitor, and the thickness of the printed silver paste is controlled in the range of 5 to 12 ⁇ m. within.
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the ceramic green ceramic film with a portion of the unprinted electrode are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in a vacuum sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing process parameters are: pressure 20-40 MPa, temperature 50-90 ° C, Hold pressure 5 ⁇ 30Min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 200 ° C to 500 ° C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmospheric condition.
• the sintering temperature of the product is 800 to 950 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• the silver layer of the silver-plated rear end of the filter of the present invention is accompanied by an impurity or a glass phase produced by burning silver, which affects the effect of the plating plating, and the surface of the product is subjected to surface treatment to remove the residue on the surface of the product before plating. Then, according to the plating requirements of the product, the plating conditions are selected on the electroplating line by selecting appropriate plating process conditions.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.
• Embodiments 1 to 3 RF low-pass filters with cutoff frequencies of 145 MHz, 350 MHz, and 459 MHz were prepared, respectively.
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters.
• the dielectric loss angle of the high-frequency ceramic material is selected to be less than 6*10 -4 , and the ceramic material has a sintering temperature of 860 ° C.
• the dielectric constant selection corresponding to the three embodiments is shown in Table 2.
• Example 1 2 3 Cutoff frequency (MHz) 145 350 430 Material dielectric constant 50 36 20
• the ceramic material performance parameters are also examined: the dielectric strength of the material, the temperature coefficient of the capacitor, its compatibility with the silver paste, its frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvent, plasticizer, binder and dispersant
• organic solvent including organic solvent, plasticizer, binder and dispersant
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast in the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 35. Micron, the error is controlled within ⁇ 0.5 microns.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing.
• the inductive conductor is printed by the hole-filled ceramic green porcelain diaphragm, and the positive electrode and the ground electrode of the built-in capacitor are printed by using the partially unperforated ceramic dielectric film, and the thickness of the printing silver paste is controlled within the range of 6 ⁇ 0.5 ⁇ m. .
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the partial unprinted electrode film are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in an evacuated sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing preferably has a pressure of 18 MPa, a temperature of 70 ° C, and a holding pressure of 30 min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 430 °C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmospheric condition.
• the sintering temperature of the product is about 860 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• step 10 After the product in step 10 is burned with silver, electroplating is performed on the electroplating line according to the plating requirements of the product.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.
• Examples 4-6 Preparation of RF low-pass filters with cutoff frequencies of 460 MHz, 700 MHz, and 1200 MHz, respectively
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters.
• the dielectric loss angle of the high-frequency ceramic material is selected to be less than 6*10 -4 , and the ceramic material has a sintering temperature of 880 ° C.
• the dielectric constant selection corresponding to the three embodiments is shown in Table 4.
• the ceramic material performance parameters are also examined: the dielectric strength of the material, the temperature coefficient of the capacitor, its compatibility with the silver paste, its frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvent, plasticizer, binder and dispersant
• organic solvent including organic solvent, plasticizer, binder and dispersant
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast in the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 30. Micron, the error is controlled within ⁇ 0.5 microns.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing. Inductive conductor printing is carried out with a hole-filled ceramic green porcelain diaphragm, and a positive electrode and a ground electrode of the built-in capacitor are printed by a partially unperforated ceramic dielectric film, and the thickness of the printed silver paste is controlled within a range of 7 ⁇ 0.5 ⁇ m. .
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the partial unprinted electrode film are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in an evacuated sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing preferably has a pressure of 20 MPa, a temperature of 65 ° C, and a holding pressure of 25 min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 500 °C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmospheric condition.
• the sintering temperature of the product is about 880 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• step 10 After the product in step 10 is burned with silver, electroplating is performed on the electroplating line according to the plating requirements of the product.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.
• Example 3 Preparation of a radio frequency low pass filter with a cutoff frequency of 1750 MHz
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters.
• the dielectric loss angle of the high-frequency ceramic material is selected to be less than 6*10 -4 , and the ceramic material has a sintering temperature of 880 ° C.
• Example 7 9 Cutoff frequency (MHz) 1300 1750 3500 Material dielectric constant 9.8 8.5 6.3
• the ceramic material performance parameters are also examined: the dielectric strength of the material, the temperature coefficient of the capacitor, its compatibility with the silver paste, its frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvent, plasticizer, binder and dispersant
• organic solvent including organic solvent, plasticizer, binder and dispersant
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast in the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 30. Micron, the error is controlled within ⁇ 0.5 microns.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing.
• the inductive conductor is printed by the hole-filled ceramic green porcelain diaphragm, and the positive electrode and the ground electrode of the built-in capacitor are printed by using the partially unperforated ceramic dielectric film, and the thickness of the printed silver paste is controlled within the range of 8 ⁇ 0.5 ⁇ m. .
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the partial unprinted electrode film are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in an evacuated sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing preferably has a pressure of 28 MPa, a temperature of 70 ° C, and a holding pressure of 18 min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 450 °C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmospheric condition.
• the sintering temperature of the product is about 880 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• step 10 After the product in step 10 is burned with silver, electroplating is performed on the electroplating line according to the plating requirements of the product.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.
• Embodiments 10-11 RF low-pass filters with cutoff frequencies of 3600 MHz and 4850 MHz, respectively
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters.
• the dielectric loss angle of the high-frequency ceramic material is selected to be less than 6*10 -4 , and the ceramic material has a sintering temperature of 900 ° C.
• the cutoff frequencies of the filters are 3600 MHz and 4850 MHz, respectively, and the dielectric constants of the selected dielectric materials are 5.7 and 4.3, respectively.
• the ceramic material performance parameters are also examined: the dielectric strength of the material, the temperature coefficient of the capacitor, its compatibility with the silver paste, its frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvent, plasticizer, binder and dispersant
• organic solvent including organic solvent, plasticizer, binder and dispersant
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast on the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 25 Micron, the error is controlled within ⁇ 0.5 microns.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing.
• the inductive conductor is printed by the hole-filled ceramic green porcelain diaphragm, and the positive electrode and the ground electrode of the built-in capacitor are printed by using the partially unperforated ceramic dielectric film, and the thickness of the printed silver paste is controlled within the range of 8 ⁇ 0.5 ⁇ m. .
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the partial unprinted electrode film are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in an evacuated sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing preferably has a pressure of 30 MPa, a temperature of 60 ° C, and a holding pressure of 10 min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 460 °C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmospheric condition.
• the sintering temperature of the product is about 900 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• step 10 After the product in step 10 is burned with silver, electroplating is performed on the electroplating line according to the plating requirements of the product.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.
• Example 12 Preparation of a radio frequency low pass filter with a cutoff frequency of 7600 MHz
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters.
• the dielectric loss angle of the high-frequency ceramic material is selected to be less than 6*10 -4 , and the ceramic material has a sintering temperature of 900 ° C.
• the filter has a cutoff frequency of 7600MHz, the cutoff frequency is above 3600MHz, and the dielectric material selected here is a dielectric constant of 4.0.
• the ceramic material performance parameters are also examined: the dielectric strength of the material, the temperature coefficient of the capacitor, its compatibility with the silver paste, its frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvent, plasticizer, binder and dispersant
• organic solvent including organic solvent, plasticizer, binder and dispersant
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast in the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 35. Micron, the error is controlled within ⁇ 0.5 microns.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing. Inductive conductor printing is carried out with a hole-filled ceramic green porcelain diaphragm, and a positive electrode and a ground electrode of the built-in capacitor are printed by a partially unperforated ceramic dielectric film, and the thickness of the printed silver paste is controlled within a range of 8 ⁇ 1 ⁇ m. .
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the partial unprinted electrode film are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in an evacuated sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing preferably has a pressure of 25 MPa, a temperature of 60 ° C, and a holding pressure of 18 min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 450 °C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmospheric condition.
• the sintering temperature of the product is about 900 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• step 10 After the product in step 10 is burned with silver, electroplating is performed on the electroplating line according to the plating requirements of the product.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.
• Example 13 Preparation of a radio frequency low pass filter with a cutoff frequency of 9100 MHz
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters.
• the dielectric loss angle of the high-frequency ceramic material is selected to be less than 6*10 -4 , and the ceramic material has a sintering temperature of 900 ° C.
• the filter has a cutoff frequency of 9100MHz, the cutoff frequency is above 3600MHz, and the dielectric material selected here is 3.7.
• the ceramic material performance parameters are also examined: the dielectric strength of the material, the temperature coefficient of the capacitor, its compatibility with the silver paste, its frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvent, plasticizer, binder and dispersant
• organic solvent including organic solvent, plasticizer, binder and dispersant
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast in the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 35. Micron, the error is controlled within ⁇ 0.5 microns.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing. Inductive conductor printing is carried out with a hole-filled ceramic green porcelain diaphragm, and a positive electrode and a ground electrode of the built-in capacitor are printed by a partially unperforated ceramic dielectric film, and the thickness of the printed silver paste is controlled within a range of 8 ⁇ 1 ⁇ m. .
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the partial unprinted electrode film are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in an evacuated sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing preferred parameters are: pressure 20 MPa, temperature 60 ° C, pressure holding 20 Min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 450 °C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmospheric condition.
• the sintering temperature of the product is about 900 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• step 10 After the product in step 10 is burned with silver, electroplating is performed on the electroplating line according to the plating requirements of the product.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.
• Example 14 Preparation of a low-pass filter with a cutoff frequency of 30800 MHz
• Step 1 Selection of high frequency ceramic materials. Select the appropriate high frequency ceramic material based on the filter performance parameters.
• the dielectric loss angle of the high-frequency ceramic material is selected to be less than 6*10 -4 , and the ceramic material has a sintering temperature of 890 ° C.
• the filter has a cutoff frequency of 30800MHz, the cutoff frequency is above 3600MHz, and the dielectric material selected here is a dielectric constant of 3.5.
• the ceramic material performance parameters are also examined: the dielectric strength of the material, the temperature coefficient of the capacitor, its compatibility with the silver paste, its frequency of use, and the like.
• Step 2 Formulation of the casting slurry.
• a suitable solvent system including organic solvent, plasticizer, binder and dispersant
• organic solvent including organic solvent, plasticizer, binder and dispersant
• Step 3 Ball milling, casting. After the casting slurry prepared in the step 2 is pulped by selecting an appropriate ball milling process, the ceramic green ceramic film of the desired thickness is cast in the casting machine according to the needs of the designed diaphragm, and the thickness of the film is 45. Micron, the error is controlled within ⁇ 0.5 microns.
• Step 4 Punch and fill holes. Part of the ceramic green ceramic film obtained in the step 3 is perforated according to the connection between the inductance and the capacitance and the connection between the inductances. The pores are then filled with silver paste.
• Step 5 Conductor printing. Inductive conductor printing is carried out with a hole-filled ceramic green porcelain diaphragm, and a positive electrode and a ground electrode of the built-in capacitor are printed by a partially unperforated ceramic dielectric film, and the thickness of the printed silver paste is controlled within a range of 8 ⁇ 1 ⁇ m. .
• Step 6 Lamination, pressing.
• the ceramic green ceramic film printed with the electrode and the partial unprinted electrode film are laminated and pressed according to the structure designed according to the present invention.
• Step 7 Isostatic pressing.
• the laminated chip filter ceramic plate is placed in an evacuated sealed bag and placed in an isostatic press for isostatic pressing.
• the isostatic pressing preferred parameters are: pressure 20 MPa, temperature 60 ° C, pressure holding 20 Min.
• Step 8 Dispense.
• the debinding process is a process of gasification and burning of the organic binder, and is a necessary process before sintering, and the temperature is set at 450 °C.
• the debinding process has a serious impact on the quality of the low temperature co-fired RF filter (LTCC RF filter). If the debinding is not sufficient, the multi-layer body will be foamed, deformed or layered after sintering; It is also possible to cause the metallized pattern to fall off and the like. Therefore, it is necessary to strictly control the debinding process, especially the heating rate.
• Step 9 After the completion of the debinding, the sintering process is entered.
• the sintering is a process of densifying the LTCC product under high temperature conditions under a certain atmosphere.
• the sintering temperature of the product is 890 °C.
• the sintering mechanism in the sintering process is complicated. How to ensure the same degree of shrinkage of the metallized slurry and the strip is the key to the sintering process.
• the process parameters mainly include heating rate, heating time, holding time, cooling time, etc., all of which need to be strict. control. For example, the phenomenon of "bulging" of small holes in the sample of the LTCC filter is also caused by different degrees of shrinkage of the metallized paste and the strip.
• Step 10 Apply silver and seal.
• the silver-coated portion is the middle portion of the side, and the end portion is the both ends of the product, as shown in the three views in FIG. 2, and the black portion is the electrode.
• the radio frequency filter of the invention has four terminals, the middle end electrode adopts rolling silver coating (see Fig. 6), and the two end electrodes are blocked by silver bonding.
• the silver coating of the middle end electrode is one of the difficulties in the preparation of the filter of the present invention, and the silver coating wheel must be designed according to the shape and size of the product in order to ensure the precision of the outer shape and thickness of the terminal electrode.
• Step 11 End processing.
• step 10 After the product in step 10 is burned with silver, electroplating is performed on the electroplating line according to the plating requirements of the product.
• the laminated chip ceramic radio frequency low pass filter of the present invention can be obtained.

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• 2014
  • 2014-04-03 WO PCT/CN2014/074689 patent/WO2015149317A1/zh active Application Filing
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