Inductor framework of LTCC (Low Temperature Co-Fired Ceramic) filter and preparation method thereof

Abstract

The invention discloses an inductor framework of an LTCC (Low Temperature Co-fired Ceramic) filter and a preparation method thereof, belongs to the technical field of LTCC, and solves the problem that the quality factor Q of a lamination structure inductor is lower than that of a winding structure inductor. The inductor specifically comprises a plurality of inductance coils which are transversely and spirally distributed; the inductance coil comprises a first layer inductance circuit, one end of the first layer inductance circuit is connected with a cylinder circuit, the top of the cylinder circuit is connected with a second layer inductance circuit, and the second layer inductance circuit is connected with the first layer inductance circuit of the next circle of inductance coil through another cylinder circuit. According to the LTCC filter inductor framework, the inductance coils are transversely and spirally distributed, the Q value of the LTCC filter inductor framework is increased through the transverse design, the degree of freedom of design space can be increased under the laminated structure design, and the purpose of miniaturization design is achieved. The preparation method of the inductor framework is simple in process, processing and preparation are carried out through conventional processes such as punching, hole filling, printing and laminating, and the inductor framework is suitable for large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature co-fired ceramics, and in particular to an inductor structure of an LTCC filter and a preparation method thereof. Background Art

[0002] LTCC (Low-Temperature Co-fired Ceramic) is an electronic component featuring a 3D structure composed of capacitors and inductors. The LC resonant unit is the most commonly used passive network in LTCC RF circuits. It can be constructed in both parallel and series configurations and is a crucial component of filters. The amplitude-frequency and phase-frequency characteristics of the LC resonant circuit enable frequency selection—selecting useful frequency components while suppressing unwanted frequency signals or noise—as well as frequency-amplitude and frequency-phase conversion, for example, in slope and phase frequency detection.

[0003] LTCC is made using traditional multilayer ceramic technology and then processed. Figure 1 As shown in the figure, the traditional LTCC low-temperature co-fired ceramic uses a laminated structure design. When preparing the inductor structure, the ceramic green tape and coil circuit are designed on a plane layer to make a sheet of green tape. Then, through laser drilling, metal paste is used to make through-hole electrodes in micropores and precision printing is used to prepare the inductor circuit pattern to form the internal circuit electrode. Finally, the inductor circuit pattern is heated and dried to obtain a green tape covered with metal electrodes, as shown in the figure. Figure 2 As shown in the figure, after preparing multiple layers of green ceramic tape with metal electrodes, they are heated, dried, and laminated. They are then cut into granules, debonded, and sintered. Finally, post-processing processes including edge rolling, silver termination, sintering, and electroplating are used to create multiple layers of ceramic dielectric layers and multiple inductor internal circuit electrodes. This inductor design meets the requirements of LTCC filters. Compared with wire-wound structures, this design can achieve miniaturization and cost reduction, but the disadvantage is that the quality factor (Q) is lower than that of wire-wound inductors.

[0004] Since the inductance value L is directly proportional to the quality factor Q, i.e., Q = 2πfL / R, a larger quality factor Q indicates a stronger filter resolution and greater suppression of out-of-band spurious signals. Regarding inductor design, due to the multilayer structure of LTCC low-temperature co-fired ceramics, the inductor and capacitor must be incorporated within a single layer. This poses design limitations due to space and structural considerations. As a result, the Q factor of inductors using multilayer structures is lower than that of wire-wound inductors. Furthermore, due to increasing market demand and functional characteristics, miniaturization and high-frequency LTCC filter products are the future trends. High-frequency products, used in inductors operating in the high-frequency band from tens of MHz to tens of GHz, have higher Q requirements, requiring higher-Q materials and more advanced manufacturing processes. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides an inductor structure of an LTCC filter and a preparation method thereof, which solves the problem that the quality factor Q of a multilayer structure inductor is lower than that of a winding structure inductor.

[0006] In the first aspect, in order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: An inductor structure for an LTCC filter includes: a plurality of turns of inductor coils distributed in a transverse spiral; the inductor coils include a first-layer inductor circuit, one end of the first-layer inductor circuit is connected to a cylindrical circuit, the top of the cylindrical circuit is connected to a second-layer inductor circuit, and the second-layer inductor circuit is connected to the first-layer inductor circuit of the next turn of the inductor coil through another cylindrical circuit.

[0007] In this solution, the inductor coil is distributed in a horizontal spiral, and the horizontal design is used to increase the Q value of the LTCC filter inductor architecture. This can increase the design space freedom and improve the Q value under the multilayer structure design, and achieve the goal of miniaturization.

[0008] In a second aspect, the present invention provides a method for preparing an inductor structure of an LTCC filter based on the inductor structure of the first aspect, comprising the following steps: S1: Printing the first layer of inductor circuit on the bottom raw porcelain tape; S2: drilling holes in the middle layer of green porcelain tape and preparing column circuits in the holes; S3: Printing the second layer of inductor circuit on the top layer of green porcelain tape; S4: The bottom layer green porcelain tape, the middle layer green porcelain tape and the top layer green porcelain tape are stacked and pressed in order to obtain a sheet-like finished product; the sheet-like finished product is cut into granules, and the binder is removed and sintered to obtain the LTCC lateral inductor structure.

[0009] In this solution, the pattern of the inductor circuit is printed on a raw porcelain tape, and multiple layers of the raw porcelain tape are laminated, pressed, and then cut. This preparation process can be based on the preparation process of traditional low-temperature fired ceramics. It only needs to be printed according to the preset inductor circuit pattern. The operation is easy and the implementation cost is low. Compared with the winding structure inductor, it can achieve miniaturization and low cost.

[0010] Furthermore, S1 includes: S101: Printing the first layer of inductor circuit using metal paste on the bottom raw porcelain tape; S102: After printing, place the printed piece in an oven and bake it at a temperature of 40°C to 100°C for 5 to 15 minutes.

[0011] Furthermore, S2 includes: S201: drilling a first through hole on the middle layer of the green porcelain tape at a position corresponding to the first layer of the inductor circuit, and filling the first through hole with metal paste; S202: After filling, the circuit is placed in an oven and baked at a temperature of 40°C to 100°C for 5 to 15 minutes to obtain a cylindrical circuit; S203: Repeat S201 to S202 to prepare n layers of intermediate layer green porcelain tape (6) and then enter S3; wherein n is the target number of layers, and the target number of layers is 1 to 100 layers.

[0012] In this solution, the cylindrical circuit connects the first layer inductor circuit and the second layer inductor circuit, so that the two form a complete inductor coil.

[0013] Furthermore, S3 includes: S301: drilling a second through hole on the top green porcelain tape at a position corresponding to the pillar circuit, and filling the second through hole with metal paste; S302: After filling, place the substrate in an oven and bake it at 40°C to 100°C for 5 to 15 minutes to obtain a through-hole electrode. S303: Printing a second layer of inductor circuit on the top layer of green porcelain tape using metal paste; S304: After printing, place the printed piece in an oven and bake it at 40°C to 100°C for 5 to 15 minutes.

[0014] In this solution, the second through hole is filled with metal paste to form a through-hole electrode, which is used to connect the pillar circuit and the second layer inductor circuit, thereby realizing the connection between the first layer inductor circuit and the second layer inductor circuit.

[0015] Furthermore, S4 includes: S401: stacking and pressing a bottom layer of green porcelain tape, n layers of middle layer green porcelain tape, and a top layer of green porcelain tape in sequence to obtain a finished sheet; after pressing, the bottom of the cylindrical circuit is connected to the first layer of inductor circuit, and the top of the cylindrical circuit is connected to the second layer of inductor circuit via a through-hole electrode; S402: Cut the finished sheet into granules and debind at a temperature of 250-450°C; then sinter at a temperature of 850-950°C; S403: The sintered granular finished product is subjected to post-processing processes including corner rolling, silver termination, sintering and electroplating to obtain an LTCC filter element with a lateral inductor structure.

[0016] Furthermore, the aperture range of the first through hole in S201 is 30 μm to 200 μm; the aperture range of the second through hole in S301 is 30 μm to 200 μm.

[0017] Furthermore, the line width of the inductor circuit printed on the bottom green porcelain tape and the inductor circuit printed on the top green porcelain tape ranges from 30 μm to 200 μm.

[0018] Furthermore, the metal paste is silver paste or silver-palladium paste.

[0019] The beneficial effects of the present invention are: The inductor architecture of the LTCC filter of the present invention utilizes the characteristics of a lateral inductor design to increase product design space. It is not limited by dielectric thickness due to the need for a capacitor design. In order to achieve the required inductance value, the inductor design space is increased, thereby achieving the goal of miniaturization and having broad application prospects.

[0020] The fabrication method for the LTCC filter inductor structure of the present invention is simple and utilizes common fabrication processes for LTCC filter electronic components, such as punching, filling, printing, and lamination. This process can be implemented using conventional equipment and is suitable for large-scale production. The fabricated inductor structure is arranged along a transverse spiral, achieving a similar winding structure. This transverse inductor design allows for flexible increases in the number of turns within a stacked design, without the limitations of dielectric layers, resulting in a higher inductance value. Furthermore, the increased cross-sectional area enhances the inductance value, thereby improving the circuit Q factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the inductor structure of an existing LTCC filter; Figure 2 A schematic diagram of the manufacturing process of the inductor structure of the existing LTCC filter; Figure 3 Schematic diagram of the structure of an inductor architecture of an LTCC filter in an embodiment; Figure 4 FIG. 1 is a schematic diagram of a process for preparing an inductor structure of an LTCC filter in an embodiment.

[0022] Reference numerals: 1. First layer inductor circuit; 2. Pillar circuit; 3. Second layer inductor circuit; 4. Through-hole electrode; 5. Bottom layer green porcelain tape; 6. Middle layer green porcelain tape; 7. Top layer green porcelain tape; DETAILED DESCRIPTION The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0023] Example 1 like Figure 3As shown, this embodiment provides an inductor structure for an LTCC filter. The inductor structure is arranged along a horizontal spiral to realize a winding-like structure. The horizontal inductor design can increase the Q value of the LTCC filter inductor structure, increase the design space freedom under the multilayer structure design, and achieve the purpose of miniaturization. The invention specifically includes: An inductor coil with several turns arranged in a horizontal spiral. The inductor coil includes a first-layer inductor circuit 1, one end of which is connected to a cylindrical circuit 2. The top of the cylindrical circuit 2 is connected to a second-layer inductor circuit 3. The second-layer inductor circuit 3 is connected to the first-layer inductor circuit 1 of the next turn of the inductor coil through another cylindrical circuit 2.

[0024] Example 2 like Figure 4 As shown, this embodiment provides a method for preparing an inductor structure of an LTCC filter based on the inductor structure of an LTCC filter provided in Example 1, comprising the following steps: S1: Printing the first layer of inductor circuit 1 on the bottom green porcelain tape 5; specifically including: S101: Printing a first layer of inductor circuit 1 on the bottom green porcelain tape 5 using silver paste, the bottom green porcelain tape 5 having a thickness of 100 μm and a line width of 100 μm; S102: After printing, place the printed sheet in an oven and bake it at 50°C for 10 minutes.

[0025] S2: drilling holes in the middle layer of green porcelain tape 6 and preparing columnar circuits 2 in the holes; specifically including: S201: Using a punching device, a first through hole is punched in the middle layer green porcelain tape 6 at a position corresponding to the first layer inductor circuit 1. The aperture of the first through hole is 100 μm, and the thickness of the middle layer green porcelain tape 6 is 60 μm. Silver paste is filled into the first through hole. S202: After filling, the circuit is placed in an oven and baked at 50° C. for 10 minutes to obtain a cylindrical circuit 2; S203: Repeat S201 to S202 to prepare 15 layers of intermediate layer green porcelain tape (6) and then enter S3.

[0026] S3: Printing the second layer of inductor circuit 3 on the top layer of green porcelain tape 7; specifically including: S301: using a punching device to punch a second through hole at a position corresponding to the pillar circuit 2 on the top green porcelain tape 7, wherein the aperture of the second through hole is 100 μm and the thickness of the top green porcelain tape 7 is 100 μm; and filling the second through hole with silver paste; S302: After the filling is completed, it is placed in an oven and baked at a temperature of 50°C for 10 minutes to obtain a through-hole electrode 4; the second through-hole is filled with silver paste to form a through-hole electrode 4, which is used to connect the column circuit 2 and the second-layer inductor circuit 3, thereby realizing the connection between the first-layer inductor circuit 1 and the second-layer inductor circuit 3.

[0027] S303: Printing a second layer of inductor circuit 3 on the top layer of green porcelain tape 7 using silver paste, where the line width of the second layer of inductor circuit 3 is 100 μm; S304: After printing, place the printed piece in an oven and bake it at 50°C for 10 minutes.

[0028] S4: laminating and pressing the bottom green porcelain tape 5, the middle green porcelain tape 6 and the top green porcelain tape 7 in this order to obtain a sheet-like finished product; cutting the sheet-like finished product into granules, debinding, and sintering; specifically comprising: S401: The bottom layer green porcelain tape 5, the 15th layer middle layer green porcelain tape 6, and the top layer green porcelain tape 7 are laminated and pressed in order to obtain a sheet-shaped finished product; after pressing, the bottom of the pillar circuit 2 is connected to the first layer inductor circuit 1, and the top of the pillar circuit 2 is connected to the second layer inductor circuit 3 via the through-hole electrode 4; S402: Cut the finished sheet into granules and debind at 350°C; then sinter at 870°C. S403: The sintered granular finished product is subjected to post-processing processes such as corner rolling, silver termination, sintering, electroplating, external inspection and package testing to obtain an LTCC filter component with a lateral inductor structure.

[0029] In this embodiment, the silver paste may also be replaced by silver-palladium paste.

[0030] Example 3 like Figure 4 As shown, this embodiment provides a method for preparing an inductor structure of an LTCC filter based on the inductor structure of an LTCC filter provided in Example 1, comprising the following steps: S1: Printing the first layer of inductor circuit 1 on the bottom green porcelain tape 5; specifically including: S101: Printing a first layer of inductor circuit 1 on the bottom green porcelain tape 5 using silver paste, the bottom green porcelain tape 5 has a thickness of 100 μm, and the line width of the first layer of inductor circuit is 30 μm; S102: After printing, place the printed sheet in an oven and bake it at 50°C for 10 minutes.

[0031] S2: drilling holes in the middle layer of green porcelain tape 6 and preparing columnar circuits 2 in the holes; specifically including: S201: Using a punching device, a first through hole is punched in the middle layer green porcelain tape 6 at a position corresponding to the first layer inductor circuit 1. The aperture of the first through hole is 100 μm, and the thickness of the middle layer green porcelain tape 6 is 60 μm. Silver paste is filled into the first through hole. S202: After filling, the circuit is placed in an oven and baked at 50° C. for 10 minutes to obtain a cylindrical circuit 2; S203: Repeat S201 to S202 to prepare 15 layers of intermediate layer green porcelain tape (6) and then enter S3; S3: Printing the second layer of inductor circuit 3 on the top layer of green porcelain tape 7; specifically including: S301: using a punching device to punch a second through hole at a position corresponding to the pillar circuit 2 on the top green porcelain tape 7, wherein the aperture of the second through hole is 100 μm and the thickness of the top green porcelain tape 7 is 100 μm; and filling the second through hole with silver paste; S302: After the filling is completed, it is placed in an oven and baked at a temperature of 50°C for 10 minutes to obtain a through-hole electrode 4; the second through-hole is filled with silver paste to form a through-hole electrode 4, which is used to connect the column circuit 2 and the second-layer inductor circuit 3, thereby realizing the connection between the first-layer inductor circuit 1 and the second-layer inductor circuit 3.

[0032] S303: Printing a second layer of inductor circuit 3 on the top layer of green porcelain tape 7 using silver paste, where the line width of the second layer of inductor circuit 3 is 30 μm; S304: After printing, place the printed piece in an oven and bake it at 50°C for 10 minutes.

[0033] S4: laminating and pressing the bottom green porcelain tape 5, the middle green porcelain tape 6 and the top green porcelain tape 7 in this order to obtain a sheet-like finished product; cutting the sheet-like finished product into granules, debinding, and sintering; specifically comprising: S401: The bottom layer green porcelain tape 5, the 15th layer middle layer green porcelain tape 6, and the top layer green porcelain tape 7 are laminated and pressed in order to obtain a sheet-shaped finished product; after pressing, the bottom of the pillar circuit 2 is connected to the first layer inductor circuit 1, and the top of the pillar circuit 2 is connected to the second layer inductor circuit 3 via the through-hole electrode 4; S402: Cut the finished sheet into granules and debind at 350°C; then sinter at 870°C. S403: The sintered granular finished product is subjected to post-processing processes such as corner rolling, silver termination, sintering, electroplating, external inspection and package testing to obtain an LTCC filter component with a lateral inductor structure.

[0034] Example 4 like Figure 4As shown, this embodiment provides a method for preparing an inductor structure of an LTCC filter based on the inductor structure of an LTCC filter provided in Example 1, comprising the following steps: S1: Printing the first layer of inductor circuit 1 on the bottom green porcelain tape 5; specifically including: S101: Printing a first layer of inductor circuit 1 on the bottom green porcelain tape 5 using silver paste, the bottom green porcelain tape 5 having a thickness of 100 μm and a line width of 200 μm; S102: After printing, place the printed sheet in an oven and bake it at 50°C for 10 minutes.

[0035] S2: drilling holes in the middle layer of green porcelain tape 6 and preparing columnar circuits 2 in the holes; specifically including: S201: Using a punching device, a first through hole is punched in the middle layer green porcelain tape 6 at a position corresponding to the first layer inductor circuit 1. The aperture of the first through hole is 100 μm, and the thickness of the middle layer green porcelain tape 6 is 60 μm. Silver paste is filled into the first through hole. S202: After filling, the circuit is placed in an oven and baked at 50° C. for 10 minutes to obtain a cylindrical circuit 2; S203: Repeat S201 to S202 to prepare 15 layers of intermediate layer green porcelain tape (6) and then enter S3; S3: Printing the second layer of inductor circuit 3 on the top layer of green porcelain tape 7; specifically including: S301: using a punching device to punch a second through hole at a position corresponding to the pillar circuit 2 on the top green porcelain tape 7, wherein the aperture of the second through hole is 100 μm and the thickness of the top green porcelain tape 7 is 100 μm; and filling the second through hole with silver paste; S302: After the filling is completed, it is placed in an oven and baked at a temperature of 50°C for 10 minutes to obtain a through-hole electrode 4; the second through-hole is filled with silver paste to form a through-hole electrode 4, which is used to connect the column circuit 2 and the second-layer inductor circuit 3, thereby realizing the connection between the first-layer inductor circuit 1 and the second-layer inductor circuit 3.

[0036] S303: Printing a second layer of inductor circuit 3 on the top layer of green porcelain tape 7 using silver paste, where the line width of the second layer of inductor circuit 3 is 200 μm; S304: After printing, place the printed piece in an oven and bake it at 50°C for 10 minutes.

[0037] S4: laminating and pressing the bottom green porcelain tape 5, the middle green porcelain tape 6 and the top green porcelain tape 7 in this order to obtain a sheet-like finished product; cutting the sheet-like finished product into granules, debinding, and sintering; specifically comprising: S401: The bottom layer green porcelain tape 5, the 15th layer middle layer green porcelain tape 6, and the top layer green porcelain tape 7 are laminated and pressed in order to obtain a sheet-shaped finished product; after pressing, the bottom of the pillar circuit 2 is connected to the first layer inductor circuit 1, and the top of the pillar circuit 2 is connected to the second layer inductor circuit 3 via the through-hole electrode 4; S402: Cut the finished sheet into granules and debind at 350°C; then sinter at 870°C. S403: The sintered granular finished product is subjected to post-processing processes such as corner rolling, silver termination, sintering, electroplating, external inspection and package testing to obtain an LTCC filter component with a lateral inductor structure.

[0038] Example 5 like Figure 4 As shown, this embodiment provides a method for preparing an inductor structure of an LTCC filter based on the inductor structure of an LTCC filter provided in Example 1, comprising the following steps: S1: Printing the first layer of inductor circuit 1 on the bottom green porcelain tape 5; specifically including: S101: Printing a first layer of inductor circuit 1 on the bottom green porcelain tape 5 using silver paste, the bottom green porcelain tape 5 having a thickness of 100 μm and a line width of 100 μm; S102: After printing, place the printed sheet in an oven and bake it at 50°C for 10 minutes.

[0039] S2: drilling holes in the middle layer of green porcelain tape 6 and preparing columnar circuits 2 in the holes; specifically including: S201: Using a punching device, a first through hole is punched in the middle layer of green porcelain tape 6 at a position corresponding to the first layer of inductor circuit 1. The aperture of the first through hole is 30 μm, and the thickness of the middle layer of green porcelain tape 6 is 60 μm. Silver paste is then filled into the first through hole. S202: After filling, the circuit is placed in an oven and baked at 50° C. for 10 minutes to obtain a cylindrical circuit 2; S203: Repeat S201 to S202 to prepare 15 layers of intermediate layer green porcelain tape (6) and then enter S3; S3: Printing the second layer of inductor circuit 3 on the top layer of green porcelain tape 7; specifically including: S301: Using a punching device, a second through hole is punched on the top green porcelain tape 7 at a position corresponding to the pillar circuit 2. The aperture of the second through hole is 30 μm, and the thickness of the top green porcelain tape 7 is 100 μm. Silver paste is then filled into the second through hole. S302: After the filling is completed, it is placed in an oven and baked at a temperature of 50°C for 10 minutes to obtain a through-hole electrode 4; the second through-hole is filled with silver paste to form a through-hole electrode 4, which is used to connect the column circuit 2 and the second-layer inductor circuit 3, thereby realizing the connection between the first-layer inductor circuit 1 and the second-layer inductor circuit 3.

[0040] S303: Printing a second layer of inductor circuit 3 on the top layer of green porcelain tape 7 using silver paste, where the line width of the second layer of inductor circuit 3 is 100 μm; S304: After printing, place the printed piece in an oven and bake it at 50°C for 10 minutes.

[0041] S4: laminating and pressing the bottom green porcelain tape 5, the middle green porcelain tape 6 and the top green porcelain tape 7 in this order to obtain a sheet-like finished product; cutting the sheet-like finished product into granules, debinding, and sintering; specifically comprising: S401: The bottom layer green porcelain tape 5, the 15th layer middle layer green porcelain tape 6, and the top layer green porcelain tape 7 are laminated and pressed in order to obtain a sheet-shaped finished product; after pressing, the bottom of the pillar circuit 2 is connected to the first layer inductor circuit 1, and the top of the pillar circuit 2 is connected to the second layer inductor circuit 3 via the through-hole electrode 4; S402: Cut the finished sheet into granules and debind at 350°C; then sinter at 870°C. S403: The sintered granular finished product is subjected to post-processing processes such as corner rolling, silver termination, sintering, electroplating, external inspection and package testing to obtain an LTCC filter component with a lateral inductor structure.

[0042] Example 6 like Figure 4 As shown, this embodiment provides a method for preparing an inductor structure of an LTCC filter based on the inductor structure of an LTCC filter provided in Example 1, comprising the following steps: S1: Printing the first layer of inductor circuit 1 on the bottom green porcelain tape 5; specifically including: S101: Printing a first layer of inductor circuit 1 on the bottom green porcelain tape 5 using silver paste, the bottom green porcelain tape 5 having a thickness of 100 μm and a line width of 100 μm; S102: After printing, place the printed sheet in an oven and bake it at 50°C for 10 minutes.

[0043] S2: drilling holes in the middle layer of green porcelain tape 6 and preparing columnar circuits 2 in the holes; specifically including: S201: Using a punching device, a first through hole is punched in the middle layer green porcelain tape 6 at a position corresponding to the first layer inductor circuit 1. The aperture of the first through hole is 200 μm, and the thickness of the middle layer green porcelain tape 6 is 60 μm. Silver paste is filled into the first through hole. S202: After filling, the circuit is placed in an oven and baked at 50° C. for 10 minutes to obtain a cylindrical circuit 2; S203: Repeat S201 to S202 to prepare 15 layers of intermediate layer green porcelain tape (6) and then enter S3; S3: Printing the second layer of inductor circuit 3 on the top layer of green porcelain tape 7; specifically including: S301: Using a punching device, a second through hole is punched at a position corresponding to the pillar circuit 2 on the top green porcelain tape 7. The aperture of the second through hole is 200 μm, and the thickness of the top green porcelain tape 7 is 100 μm. Silver paste is filled into the second through hole. S302: After the filling is completed, it is placed in an oven and baked at a temperature of 50°C for 10 minutes to obtain a through-hole electrode 4; the second through-hole is filled with silver paste to form a through-hole electrode 4, which is used to connect the column circuit 2 and the second-layer inductor circuit 3, thereby realizing the connection between the first-layer inductor circuit 1 and the second-layer inductor circuit 3.

[0044] S303: Printing a second layer of inductor circuit 3 on the top layer of green porcelain tape 7 using silver paste, where the line width of the second layer of inductor circuit 3 is 100 μm; S304: After printing, place the printed piece in an oven and bake it at 50°C for 10 minutes.

[0045] S4: laminating and pressing the bottom green porcelain tape 5, the middle green porcelain tape 6 and the top green porcelain tape 7 in this order to obtain a sheet-like finished product; cutting the sheet-like finished product into granules, debinding, and sintering; specifically comprising: S401: The bottom layer green porcelain tape 5, the 15th layer middle layer green porcelain tape 6, and the top layer green porcelain tape 7 are laminated and pressed in order to obtain a sheet-shaped finished product; after pressing, the bottom of the pillar circuit 2 is connected to the first layer inductor circuit 1, and the top of the pillar circuit 2 is connected to the second layer inductor circuit 3 via the through-hole electrode 4; S402: Cut the finished sheet into granules and debind at 350°C; then sinter at 870°C. S403: The sintered granular finished product is subjected to post-processing processes such as corner rolling, silver termination, sintering, electroplating, external inspection and package testing to obtain an LTCC filter component with a lateral inductor structure.

[0046] Comparison group 1 like Figure 2 As shown in the figure, LTCC is manufactured using a traditional multilayer ceramic process for post-processing. The inductor is designed to design the ceramic green tape and coil circuit in a single plane layer. Figure 1 As shown; the preparation process comprises the following steps: 1. Preparation of the first layer: Printing is performed using silver paste on a green porcelain tape with a thickness of 100 μm; Print the inductor circuit on the green porcelain tape, with a line width of 100 μm; After printing is completed, it enters the oven and is baked at 50°C for 10 minutes to complete the first layer.

[0047] 2. Preparation of the second layer: A 100 μm diameter through-hole was punched on a 60 μm thick green ceramic tape at the location corresponding to the designed internal inductor circuit. The through-hole was then filled with silver paste. After the hole filling is completed, the through-hole electrode is completed by placing it in an oven and baking it at 50°C for 10 minutes. Print the inductor circuit on the green porcelain tape, with a line width of 100 μm; After printing is completed, put it into the oven and bake it at 50℃ for 10 minutes to complete the second layer.

[0048] The preparation of the second layer was repeated to prepare 15 layers of the second layer.

[0049] 3. Preparation of the third layer: A through hole with a diameter of 100 μm is punched on a 100 μm thick green porcelain tape at the location corresponding to the designed internal inductor circuit. The green porcelain tape with the through hole is then filled with silver paste. After the hole filling is completed, the through-hole electrode is completed by placing it in an oven and baking it at 50°C for 10 minutes. After baking, the internal circuit electrodes are printed with a circuit line width of 100μm; After printing is completed, put it into the oven and bake it at 50℃ for 10 minutes.

[0050] 4. Laminate the first layer, the second layer and the third layer: The first layer to the last layer are laminated and pressed in sequence to obtain a multi-layered sheet product. The sheet product is then cut into granules, debonded at 350°C, and sintered at 870°C. The final process is followed by rolling, silvering, sintering, and electroplating to produce a flat-designed LTCC filter electronic component, such as Figure 1 shown.

[0051] Test example: The LTCC filters prepared according to the preparation methods of Examples 2-6 and Comparative Group 1 were characterized. The characterization results are shown in the following table:

[0052] The electrical performance results of Example 2 and Comparison Group 1 clearly confirm that the insertion loss of the horizontally designed LTCC filter electronic component in Example 2 is reduced from 3.048dB to 2.288dB at 2.2GHz, and the Q value is improved from 522 to 1883, compared to the traditional planar-designed LTCC filter electronic component in Comparison Group 1. Similar results are also observed for the horizontally designed LTCC filter electronic components of Examples 3-6.

[0053] Those skilled in the art will appreciate that the embodiments herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the invention.

Claims

1. An inductor structure of an LTCC filter, characterized in that: include: Several turns of inductor coils distributed in a transverse spiral; The inductor coil comprises a first layer of inductor circuit (1), one end of the first layer of inductor circuit (1) is connected to a column circuit (2), the top of the column circuit (2) is connected to a second layer of inductor circuit (3), and the second layer of inductor circuit (3) is connected to the first layer of inductor circuit (1) of the next circle of the inductor coil through another column circuit (2).

2. A method for preparing the inductor structure of the LTCC filter according to claim 1, characterized in that: The following steps are involved: S1: Printing the first layer of inductor circuit (1) on the bottom raw porcelain tape (5); S2: drilling holes in the middle layer of green porcelain tape (6) and preparing columnar circuits (2) in the holes; S3: Printing a second layer of inductor circuit (3) on the top layer of green porcelain tape (7); S4: laminating and pressing the bottom layer green porcelain tape (5), the middle layer green porcelain tape (6) and the top layer green porcelain tape (7) in this order to obtain a sheet-like finished product; cutting the sheet-like finished product into granules, debinding and sintering the granules to obtain a LTCC lateral inductor structure.

3. The method for preparing the inductor structure of the LTCC filter according to claim 2, characterized in that: Said S1 comprises: S101: Printing a first layer of inductor circuit (1) on the bottom raw porcelain tape (5) using metal paste; S102: After printing, place the printed piece in an oven and bake it at a temperature of 40°C to 100°C for 5 to 15 minutes.

4. The method for preparing the inductor structure of the LTCC filter according to claim 3, characterized in that: The S2 includes: S201: drilling a first through hole on the middle layer of green porcelain tape (6) at a position corresponding to the first layer of inductor circuit (1), and filling the first through hole with metal paste; S202: After filling, place the circuit in an oven and bake at a temperature of 40°C to 100°C for 5 to 15 minutes to obtain a cylindrical circuit (2); S203: Repeat S201 to S202 to prepare n layers of intermediate layer green porcelain tape (6) and then enter S3; wherein n is the target number of layers, and the target number of layers is 1 to 100 layers.

5. The method for preparing the inductor structure of the LTCC filter according to claim 4, characterized in that: The S3 includes: S301: drilling a second through hole on the top ceramic tape (7) at a position corresponding to the column circuit (2), and filling the second through hole with metal paste; S302: After filling, place the plate in an oven and bake at a temperature of 40°C to 100°C for 5 to 15 minutes to obtain a through-hole electrode (4); S303: Printing a second layer of inductor circuit (3) on the top layer of green porcelain tape (7) using metal paste; S304: After printing, place the printed piece in an oven and bake it at 40°C to 100°C for 5 to 15 minutes.

6. The method for preparing the inductor structure of the LTCC filter according to claim 5, characterized in that: The S4 includes: S401: stacking and pressing the bottom layer green porcelain tape (5), n layers of middle layer green porcelain tape (6) and the top layer green porcelain tape (7) in order to obtain a sheet-shaped finished product; after pressing, the bottom of the columnar circuit (2) is connected to the first layer inductor circuit (1), and the top of the columnar circuit (2) is connected to the second layer inductor circuit (3) via the through-hole electrode (4); S402: Cut the finished sheet into granules and debind at a temperature of 250-450°C; then sinter at a temperature of 850-950°C; S403: The sintered granular finished product is subjected to post-processing processes including corner rolling, silver termination, sintering and electroplating to obtain an LTCC filter element with a lateral inductor structure.

7. The method for preparing the inductor structure of the LTCC filter according to any one of claims 4 to 5, characterized in that: The aperture range of the first through hole in S201 is 30 μm to 200 μm; the aperture range of the second through hole in S301 is 30 μm to 200 μm.

8. The method for preparing the inductor structure of the LTCC filter according to any one of claims 3 to 5, characterized in that: The line width of the inductance circuit printed on the bottom raw porcelain tape (5) and the line width of the inductance circuit printed on the top raw porcelain tape (7) range from 30 μm to 200 μm.

9. The method for preparing the inductor structure of the LTCC filter according to any one of claims 3 to 7, wherein: The metal paste is silver paste or silver palladium paste.

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