Inductor and preparation method thereof

Abstract

The invention belongs to the field of inductors, and particularly discloses an inductor and a preparation method thereof. The through hole conductor is designed to be of a structure protruding towards the inner side of the coil conductor, and the outer edge of the through hole conductor is tangent to the outer edge of the wire layer, so that inward turning of connection points in the inductor is achieved. According to the design, the problem of connection point exposure caused by cutting deviation can be effectively improved, and the risk of exposure of the inner electrode is remarkably reduced. Meanwhile, the available area of the coil conductor design is increased after the connection points are turned inwards, so that the inductance value design upper limit of the inductor product is improved, and the electrical performance and the reliability of the product are comprehensively improved; meanwhile, the diameter of the through hole conductor is larger than the line width of the wire layer, the connection point area can be increased, the connection effect is improved, resistance and open circuit risks are reduced, and the electrical performance and reliability of products are improved.

Description

Technical Field

[0001] This invention belongs to the field of inductors, and specifically relates to an inductor and its preparation method. Background Technology

[0002] Multilayer chip inductors are among the most commonly used ceramic multilayer electronic components in electronic products and modern equipment. In recent years, the demand for miniaturization of inductor products has been increasing. However, size reduction leads to a decrease in the effective magnetic circuit cross-sectional area inside the product, which in turn reduces the inductance value, limiting the maximum designable inductance value of miniaturized products and consequently reducing performance.

[0003] Typically, the fabrication process for inductor blanks includes: creating an insulating dielectric layer and coil conductor patterns (including vias) using photosensitive materials, followed by multiple layers, cutting, and sintering to obtain the final product. The vias in the coil conductor patterns are often created by photolithography on the photosensitive insulating dielectric layer using exposure and development. Due to limitations in the manufacturing process, deviations may occur during product fabrication and cutting. After cutting, the internal electrodes may be exposed, leading to electrical defects. Furthermore, due to the characteristics of photosensitive materials, the cured area after exposure is usually larger than the designed area. Since the insulating dielectric layer requires vias, the aperture size typically decreases after exposure, reducing the area of ​​the connection points and worsening the connection effect. This can result in abnormal product performance and decreased product reliability. Summary of the Invention

[0004] To address the problems mentioned above in the prior art, the present invention will provide an inductor and a method for its fabrication.

[0005] To achieve the above objectives, the following technical solutions are specifically included:

[0006] In a first aspect, the present invention provides an inductor comprising a blank formed by stacking multiple dielectric layers, a coil conductor disposed inside the blank, a first external electrode, and a second external electrode. The first and second external electrodes are disposed on the outer surface of the blank and electrically connected to the coil conductor. The blank has a lower surface, a first side surface connected to the lower surface, and a second side surface. The first external electrode is composed of a first lower portion disposed on the lower surface and a side portion disposed on the first side surface, and the first lower portion and the side portion of the first side surface are interconnected. The second external electrode is composed of a second lower portion disposed on the lower surface and a side portion disposed on the second side surface, and the second lower portion and the side portion of the second side surface are interconnected.

[0007] The coil conductor includes multiple conductor layers and through-hole conductors connecting adjacent conductor layers. The conductor layers are disposed on multiple dielectric layers inside the blank and extend in the plane of the dielectric layers. The through-hole conductors penetrate the dielectric layers between adjacent conductor layers along the thickness direction of the dielectric layers. The conductor layers and the through-hole conductors are interconnected to form a three-dimensional spiral structure.

[0008] Viewed from above in the stacking direction, the through-hole conductor protrudes inward toward the coil conductor, the outer edge of the through-hole conductor is tangent to the outer edge of the conductor layer, and the diameter d of the through-hole conductor is greater than the linewidth w of the conductor layer.

[0009] This invention achieves an inward bend in the internal connection point of the inductor by designing the through-hole conductor to protrude inwards towards the coil conductor and ensuring that the outer edge of the through-hole conductor is tangent to the outer edge of the conductor layer. This design effectively improves the problem of exposed connection points caused by cutting deviations and significantly reduces the risk of exposed internal electrodes. Simultaneously, the inward bend increases the usable area for the coil conductor design, thereby increasing the upper limit of the inductance value design for the inductor product and comprehensively improving the product's electrical performance and reliability. Furthermore, the diameter d of the through-hole conductor is larger than the linewidth w of the conductor layer, which increases the connection point area, improves the connection effect, reduces resistance and open-circuit risk, and enhances the product's electrical performance and reliability.

[0010] Preferably, the dielectric layer comprises an insulating material.

[0011] Preferably, the coil conductor comprises a metal, and the metal comprises Ag.

[0012] Preferably, the coil conductor includes a first end and a second end respectively disposed at two ends of the coil conductor, the first end being connected to the first external electrode and the second end being connected to the second external electrode.

[0013] The first end and the second end can be separately located at the two ends of the coil conductor, or they can be connected directly through through-hole conductors to form the coil conductor without separate first and second ends. The patterns of the first end and the second end can be different from or the same as the patterns of the conductor layers.

[0014] Preferably, the coil conductor satisfies the following relationship: 10% ≤ (dw) / w ≤ 300%, where d is the diameter of the through-hole conductor and w is the linewidth of the conductor layer.

[0015] More preferably, the coil conductor satisfies the following relationship: w < 25 μm, 100% ≤ (dw) / w ≤ 300%.

[0016] More preferably, the coil conductor satisfies the following relationship: w > 25 μm, 30% ≤ (dw) / w ≤ 150%.

[0017] Through-hole conductors, serving as connection points for coil conductors, are relatively small in size. They are typically created by photolithography to open vias, which are then filled with conductive material. Due to their small size, the amount of light received during photolithography is difficult to control, easily leading to excessive light exposure. This can cause deviations in the position and size of the through-hole, resulting in a deterioration in the conductivity of the conductor. When the diameter of the through-hole conductor is larger than the linewidth of the conductor layer, the larger size of the through-hole conductor avoids conductivity degradation caused by excessive light exposure. It also improves the taper deviation of the hole wall, preventing the formation of a "sandwich structure" (abnormal mixing of conductor and insulation material), enhancing connection reliability, reducing the risk of open circuits caused by structural defects, improving the mechanical and electrical stability of the connection point, and mitigating the "sandwich structure" to prevent interlayer cracking caused by differences in sintering stress between the conductor and insulator, further strengthening product reliability.

[0018] Preferably, the blank further includes an upper surface opposite the lower surface. Viewed from the stacking direction, the shortest distance between the outer edge of the coil conductor and the upper surface is L1, where L1 ≥ 20 μm. When L1 ≥ 20 μm, the upper edge of the coil conductor is farther from the upper surface of the blank, reducing the risk of coil conductor exposure and preventing electrical defects caused by exposed inner electrodes.

[0019] More preferably, L1 = 20μm-70μm.

[0020] Preferably, the shortest distance between the outer edge of the coil conductor and the lower surface is L2, where L2 ≥ 20 μm. When L2 ≥ 20 μm, the lower edge of the coil conductor is farther from the lower surface of the blank, which can reduce the risk of coil conductor exposure and prevent electrical defects caused by exposed inner electrodes.

[0021] More preferably, L2 = 20μm-70μm.

[0022] The smaller L1 and L2 are, the longer the total length of the single-layer conductor can be, thus increasing the total length of the coil conductor. This results in a larger area enclosed by the closed loop formed by the coil conductor, leading to higher inductance and magnetic flux. Maintaining L1 and L2 between 20μm and 70μm ensures a suitable distance between the coil conductor and the upper and lower surfaces of the blank. This reduces the risk of exposed coil conductors while increasing the total length of the coil conductor and the area enclosed by the closed loop. Specifically, the total length of the coil conductor increases by 10-15%, and the area enclosed by the closed loop increases by 15%-20%.

[0023] Preferably, in the inductor, when two adjacent conductor layers are connected in series and / or parallel, each conductor layer is provided with at least one through-hole conductor. Adjacent conductor layers are connected through one or more through-hole conductors to form a series and / or parallel structure.

[0024] Preferably, the through-hole conductor is disposed at the end and / or middle position of the conductor layer.

[0025] Preferably, when viewed from the stacking direction, the coil conductor includes at least one of a circle or a square.

[0026] When the through-hole conductor is square, the diameter of the through-hole conductor is the side length of the through-hole conductor or the diameter of the inscribed circle.

[0027] Preferably, when viewed from above in the stacking direction, the first external electrode is formed in an L-shape.

[0028] Preferably, when viewed from above in the stacking direction, the second external electrode is formed in an L-shape.

[0029] In a second aspect, the present invention provides a method for preparing the inductor described above, comprising the following preparation method:

[0030] S1. Prepare the first insulating grout layer using insulating grout;

[0031] S2. Photosensitive conductive silver paste is coated on the first insulating paste layer, and after exposure and development, an unsintered conductor layer, a portion of the first external electrode base layer and a portion of the second external electrode base layer, and an optional first end are formed in the configuration of the first insulating layer.

[0032] S3. Coat the product obtained in step S2 with a photosensitive insulating material, and after exposure and development, form through holes corresponding to the through-hole conductors, as well as through grooves connecting the local parts of the first external electrode base layer and the local parts of the second external electrode base layer of the two adjacent layers. Fill the through grooves and through holes with a photosensitive conductive paste to form the unsintered first external electrode base layer, the base layer of the second external electrode, and the through-hole conductors arranged on the first insulating paste layer.

[0033] S4. Following the steps S1-S3 above, a multilayer insulating paste layer and its corresponding unsintered conductive layer, first external electrode base layer, second external electrode base layer and through-hole conductor are stacked to obtain a laminate; optionally, a second end is prepared on the end of the last unsintered conductive layer.

[0034] S5. The laminated body is cut and sintered to obtain a blank;

[0035] S6. Electroplating is performed on the blank at positions corresponding to the first external electrode base layer and the second external electrode base layer to form a first external electrode epitaxial layer and a second external electrode epitaxial layer. The first external electrode base layer, the first external electrode epitaxial layer, the second external electrode base layer, and the second external electrode epitaxial layer respectively constitute a complete first external electrode and a second external electrode, thereby obtaining the inductor.

[0036] Compared to existing technologies, this invention offers the following advantages: By configuring the through-hole conductor as a structure protruding inwards towards the coil conductor and ensuring the outer edge of the through-hole conductor is tangent to the outer edge of the conductor layer, an inward bend is achieved at the internal connection point of the inductor. This design effectively mitigates the problem of exposed connection points caused by cutting deviations, significantly reducing the risk of exposed internal electrodes. Simultaneously, the inward bend at the connection point increases the usable area for the coil conductor design, thereby raising the upper limit of the inductance design and comprehensively improving the product's electrical performance and reliability. Furthermore, setting the diameter of the through-hole conductor to be larger than the linewidth of the conductor layer increases the connection point area, improves the connection effect, reduces resistance and open-circuit risk, and enhances the product's electrical performance and reliability. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of an inductor structure;

[0038] Figure 2 A top-down (transparent) view of the coil conductor, dielectric layer, first external electrode, and second external electrode from the stacking direction;

[0039] Figure 3 This is an exploded perspective view of one type of inductor, which contains multiple dielectric layers, multiple conductive layers, and multiple through-hole conductors. Each conductive layer is electrically connected through the through-hole conductor at its end.

[0040] Figure 4 This is an exploded perspective view of one type of inductor, which contains multiple dielectric layers, multiple conductive layers, and multiple through-hole conductors. Each conductive layer is electrically connected through the through-hole conductor at its end.

[0041] Figure 5 This is an exploded perspective view of one type of inductor, which contains multiple dielectric layers, multiple conductive layers, and multiple through-hole conductors. Each conductive layer is electrically connected through the through-hole conductor at its end.

[0042] Figure 6 This is an exploded perspective view of one type of inductor, which contains multiple dielectric layers, multiple conductive layers, and multiple through-hole conductors. Each conductive layer is electrically connected through the through-hole conductors at its ends and / or in the middle.

[0043] Figure 7 Schematic diagrams of circular through-hole conductors and square through-hole conductors, as well as schematic diagrams of their structures tangent to the conductor layer;

[0044] Figure 8 A schematic diagram of a coil conductor structure formed by the intersection of a circular through-hole conductor and a conductor layer;

[0045] Explanation of reference numerals in the attached drawings: 1-Blank body; 10-Dielectric layer; 11-Upper surface of the blank body; 12-Lower surface of the blank body; 13-First side surface of the blank body; 14-Second side surface of the blank body; 2-Coil conductor; 21-First end; 22-Second end; 23-Wire layer in the coil conductor; 24-Through-hole conductor in the coil conductor; 3-First external electrode; 4-Second external electrode;

[0046] Furthermore, to further illustrate the connection relationship between the conductor layer 23 and the via conductor 24 between different dielectric layers 10, the present invention provides four exemplary connection schemes, respectively corresponding to... Figures 3-6 An exploded 3D view of an inductor, and a detailed view of each part. Figures 3-6 Multiple dielectric layers 10, conductive layers 23, and through-hole conductors 24 are labeled. The multiple dielectric layers 10 are labeled as 10-1 to 10-28, the conductive layers 23 are labeled as 23-1 to 23-28, and the multiple through-hole conductors 24 are labeled as 24-1a, 24-1b, 24-1c, 24-2a, 24-2b, 24-2c, 24-3a to 24-10a, 24-3b to 24-10b, 24-11a, 24-11b, 24-11c, 24-12a to 24-22a, and 24-12b to 24-22b. The long dashed lines in the figure represent the connections of each through-hole conductor 24 at the corresponding positions. Detailed Implementation

[0047] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0048] It should be understood that in the description of this invention, the terms "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. That is, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, unless otherwise stated, "a plurality of" means two or more.

[0049] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] This invention provides an inductor, the structure of which is shown in the figure below. Figures 1-7 As shown, the inductor includes a blank 1, a coil conductor 2, a first external electrode 3, and a second external electrode 4. When the inductor is working, the first external electrode 3 and the second external electrode 4 are connected in the circuit. After being energized, the coil conductor 2 converts electrical energy into magnetic energy and stores it. When no current is flowing through the inductor, it will attempt to impede the current flow when the circuit is closed; conversely, when current is flowing through the inductor, it will attempt to maintain a constant current when the circuit is open.

[0051] The billet 1 includes multiple components along the width direction of the billet 1 (e.g., ...). Figure 1 The dielectric layers 10 are stacked in the Z direction, each dielectric layer 10 being composed of an insulating material, including at least one of ceramics, glass resins, and ferrites, for example, silicon dioxide and alumina; more specifically, it may include the following components in mass percentage: alumina 10-20%, silicon dioxide 25-40%, boron oxide 0-10%, potassium oxide 0-5%, resin 34-40%, initiator 0.1-1%, solvent 3-9%, and dispersant 0.4-0.8%. The preform 1 is generally cuboid in shape. More specifically, such as... Figure 1 As shown, the blank 1 has: an upper surface 11 consisting of length and width, and a lower surface 12 opposite to the upper surface 11, a first side surface 13 consisting of width and height, and a second side surface 14 opposite to the first side surface 13.

[0052] like Figure 2 As shown, a coil conductor 2 is disposed inside the blank 1. The coil conductor 2 is helical, with its axis perpendicular to the first side 13 and the second side 14, and parallel to the upper surface 11 or the lower surface 12. The coil conductor 2 includes a first end 21 and a second end 22, and the first end 21 and the second end 22 are oriented in opposite directions. Between the first end 21 and the second end 22, there are a plurality of conductive layers 23 extending along the stacking direction and a plurality of through-hole conductors 24 penetrating the dielectric layer 10 between adjacent conductive layers 23 along the thickness direction of the dielectric layer 10. The conductive layers 23 and the through-hole conductors 24 are connected to form a three-dimensional helical structure.

[0053] Viewed from above in the stacking direction, the coil conductor 2 appears as a ring-shaped track. The interior space enclosed by this ring-shaped track is defined as the interior of the coil conductor 2. The side of the coil conductor 2 closest to the interior is the inner edge, and the side of the coil conductor 2 furthest from the interior or closest to the edge of the blank 1 is the outer edge. Correspondingly, the inner edge of the conductor layer 23 is considered to be located inside the coil conductor 2, and the outer edge of the conductor layer 23 is considered to be located outside the conductor layer 23. The coil conductor 2 has multiple conductor layer 23 patterns, each conductor layer 23 disposed on the dielectric layer 10, arranged at intervals through the dielectric layer 10, each forming part of a spiral structure. The conductor layer 23 can have various shapes, including rectangles, polygons, circles, ellipses, or combinations of these shapes, and can be designed according to actual circuit requirements. For example, it can include elongated conductor layers 23 and shapes that give partial curvature or bending to the elongated conductor layer 23. The direction orthogonal to the extension direction of the conductor layer 23 is defined as the width direction of the conductor layer 23 and the through-hole conductor 24. The width dimension of the conductor layer 23 is the linewidth of the conductor layer 23, denoted by w. The width dimension of the through-hole conductor 24 is the diameter of the through-hole conductor 24, denoted by d. During the preparation process, conductive paste is generally printed onto the dielectric layer 10, and after exposure and development according to the designed pattern, the corresponding coil conductor 2 is obtained. The conductive paste mainly includes silver paste, which specifically may include the following components by mass percentage: Ag 70-90%, resin 5-13%, initiator 0.3-0.8%, solvent 2-4%, and dispersant 0.4-0.8%.

[0054] In the fabrication of the through-hole conductor 24, an insulating paste is printed onto the conductor layer 23 and its ends. After exposure and development, a through-hole is formed connecting the upper and lower layers of the conductive coil. The conductive paste is then filled into the through-hole, and after curing and sintering, the through-hole conductor 24 is obtained. The through-hole conductor 24 can be located at at least one end of the conductor layer 23, or it can be located in the middle between the two ends of the conductor layer 23, such as... Figure 6 The through-hole conductors 24-21a are included. In this invention, the position between the two ends of the conductor layer 23 is set as the middle (position) of the conductor layer 23.

[0055] Viewed from above along the stacking direction, the shape of the via conductor can be either circular or square, such as... Figure 7 As shown, circular through-hole conductors 24 and square through-hole conductors 24 are respectively provided at the ends of the line section.

[0056] To address the defect of exposed through-hole conductors 24 serving as connection points on the coil conductor 2, this invention tangents the outer edge of the through-hole conductor 24 to the outer edge of the conductor layer 23, with the through-hole conductor 24 protruding inwards towards the coil conductor 2. The diameter d of the through-hole conductor 24 is larger than the linewidth w of the conductor layer 23. This allows for an inward bend in the connection point within the inductor, effectively mitigating the problem of exposed connection points caused by cutting deviations and significantly reducing the risk of exposed internal electrodes. Simultaneously, the inward bend increases the usable area for the coil conductor design, thereby raising the upper limit of the inductance design and comprehensively improving the product's electrical performance and reliability. Furthermore, the larger diameter d of the through-hole conductor 24 compared to the linewidth w of the conductor layer 23 increases the connection point area, improves the connection effect, reduces resistance and open-circuit risk, and further enhances the product's electrical performance and reliability.

[0057] For example, looking down at coil conductor 2 from the stacking direction, as shown... Figure 2 and Figure 7 As shown, when the via conductor 24 is circular, its outer edge is tangent to the outer edge of the conductor layer 23, and its center is on the conductor layer 23. That is, the conductor layer 23 and the via conductor 24 partially overlap. Because the diameter d of the via conductor 24 is greater than the linewidth w of the conductor layer 23, the via conductor 24 protrudes inwards from the conductor layer 23. When the via conductor 24 is square, its outer edge is tangent to the outer edge of the conductor layer 23. That is, the outer edge of the via conductor 24 coincides with the outer edge of the conductor layer 23. Because the diameter d of the via conductor 24 (i.e., its side length or the diameter of its inscribed circle) is greater than the linewidth w of the conductor layer 23, the via conductor 24 protrudes inwards from the coil conductor 2.

[0058] The line width of the conductor layer 23 and the diameter of the through-hole conductor 24 in the coil conductor 2 satisfy the following relationship: 10% ≤ (dw) / w ≤ 300%, and more preferably, w < 25 μm, 100% ≤ (dw) / w ≤ 300%, w > 25 μm, and 30% ≤ (dw) / w ≤ 150%.

[0059] To further reduce the risk of exposed coil conductor 2, this invention defines the shortest distance between the outer edge of coil conductor 2 and the upper surface 11 of blank 1 as L1, and the shortest distance between the outer edge of coil conductor 2 and the lower surface 12 of blank 1 as L2. When L1 ≥ 20 μm and L2 ≥ 20 μm, the upper edge of coil conductor 2 is farther from the upper and lower surfaces of blank 1, i.e., farther from the edge of blank 1, which can reduce the risk of exposed coil conductor 2 and prevent electrical defects caused by exposed inner electrodes. In addition, the smaller L1 and L2 are, the longer the total length of the single-layer conductive pattern can be, increasing the total length of coil conductor 2. The area enclosed by the closed loop formed by coil conductor 2 becomes larger, resulting in higher inductance and magnetic flux. The inventors of this invention discovered that when L1 and L2 are maintained between 20μm and 70μm, the distance between the coil conductor 2 and the upper and lower surfaces of the blank 1 can be ensured to be appropriate. This reduces the risk of the coil conductor 2 being exposed, while increasing the total length of the coil conductor 2 and the area enclosed by the closed loop formed by the coil conductor 2. Specifically, the total length of the coil conductor 2 is increased by 10-15%, and the area enclosed by its closed loop is increased by 15%-20%.

[0060] A first external electrode 3 and a second external electrode 4 are respectively connected to the first end 21 and the second end 22 of the coil conductor 2 on the outer surface of the blank 1. The first external electrode 3 continuously covers a portion of the lower surface 12 and a portion of the first side surface 13 of the blank 1, and the second external electrode 4 continuously covers a portion of the lower surface 12 and a portion of the second side surface 14 of the blank 1. Both the first and second external electrodes penetrate the dielectric layer 10 perpendicularly and are connected to the first end 21 and the second end 22 of the coil conductor 2, respectively. The first external electrode 3 continuously covers the first side surface 13 and extends to the lower surface 12, and the second external electrode 4 continuously covers the second side surface 14 and extends to the lower surface 12. Specifically, the first external electrode 3 is composed of a first lower portion on the lower surface and a side portion of the first side surface, which are interconnected; the second external electrode 4 is composed of a second lower portion on the lower surface and a side portion of the second side surface, which are interconnected, but the first lower portion and the second lower portion are not connected. Viewed from the stacking direction, the two external electrodes each exhibit an L-shaped structure. When an inductor is mounted on a substrate, its L-shaped external electrode structure helps to form a good solder joint shape, thereby significantly improving installation reliability in terms of both electrical connection and mechanical fixation.

[0061] More specifically, such as Figure 3As shown, the inductor structure includes a dielectric layer 10, a plurality of conductive layers 23 disposed on the surface of the dielectric layer 10, a plurality of through-hole conductors 24 disposed at the ends of the conductive layers 23 and interconnecting adjacent conductive layers 23, and a first end 21, a second end 22, a first external electrode 3 and a second external electrode 4. The coil conductor 2 has multiple conductor layers 23-1 to 23-7 and multiple through-hole conductors 24-1a, 24-1b, 24-1c, 24-2a, 24-2b, 24-2c, 24-3a to 24-5a, 24-3b to 24-5b that interconnect adjacent conductor layers 23. The multiple conductor layers 23-1 to 23-7 are respectively disposed on dielectric layers 10-1 to 10-7. The multiple conductor layers 23-1 to 23-7 are respectively wound along the plane of dielectric layers 10-1 to 10-7. The through-hole conductors 24-1b, 24-1c and 24-2a, 24-2b enable the multiple conductor layers 23-2 to 23-3 to form a parallel electrical connection. The remaining multiple through-hole conductors 24 enable the conductor layers 23 to achieve a series electrical connection. The conductor layers 23 as a whole form a spiral. The number of turns in each conductor layer 23-1 to 23-7 is less than 1 turn, but it can also be more than 1 turn.

[0062] More specifically, such as Figure 4 As shown, the inductor structure includes a dielectric layer 10, a plurality of conductive layers 23 disposed on the surface of the dielectric layer 10, a plurality of through-hole conductors 24 disposed at the ends of the conductive layers 23 and interconnecting adjacent conductive layers 23, and a first end 21, a second end 22, a first external electrode 3 and a second external electrode 4. The coil conductor 2 has multiple conductor layers 23-8 to 23-15 and multiple through-hole conductors 24-6a to 24-10a, 24-6b to 24-10b, 24-11a, 24-11b, and 24-11c that interconnect adjacent conductor layers 23. The multiple conductor layers 23-8 to 23-15 are respectively disposed on dielectric layers 10-8 to 10-15. The multiple conductor layers 23-8 to 23-15 are respectively wound along the plane of dielectric layers 10-8 to 10-15. The through-hole conductors 24-6a to 24-10a and 24-6b to 24-10b enable the conductor layers 23-8 to 23-13 to be connected in series, and 24-11a, 24-11b, and 24-11c enable the conductor layers 23-13 to 23-15 to be connected in series, and the whole structure forms a spiral structure. Each conductor layer 23-8 to 23-14 has less than one turn, but it can also have more than one turn. Meanwhile, the second end 22 of the coil conductor 2 is composed of two parts: a second end 22a on the upper part of the dielectric layer 10-14 and a second end 22b on the upper part of the dielectric layer 10-15. The two parts, part 22a and part 22b, pass through the dielectric layers 10-14 to 10-15 between them, thus forming a parallel electrical connection structure at the end.

[0063] More specifically, such as Figure 5As shown, the inductor structure includes a dielectric layer 10, a plurality of conductive layers 23 disposed on the surface of the dielectric layer 10, a plurality of through-hole conductors 24 disposed at the ends of the conductive layers 23 and interconnecting adjacent conductive layers 23, and a first end 21, a second end 22, a first external electrode 3 and a second external electrode 4. The coil conductor 2 has multiple conductor layers 23-16 to 23-22, and multiple through-hole conductors 24-12a to 24-17a and 24-12b to 24-17b interconnecting adjacent conductor layers 23. The conductor layers 23-16 to 23-22 are respectively disposed on dielectric layers 10-16 to 10-22, and are wound along the plane of dielectric layers 10-16 to 10-22. The through-hole conductors 24-12a to 24-17a and 24-12b to 24-17b enable the conductor layers 23-16 to 23-22 to be connected in series and form a spiral structure. The number of turns in each conductor layer 23-16 to 23-22 is less than one turn, but can also be more than one turn.

[0064] More specifically, such as Figure 6 As shown, the inductor structure includes a dielectric layer 10, a plurality of conductive layers 23 disposed on the surface of the dielectric layer 10, a plurality of through-hole conductors 24 disposed at the ends and middle positions of the conductive layers 23 and interconnecting adjacent conductive layers 23, and a first end 21, a second end 22, a first external electrode 3 and a second external electrode 4. The coil conductor 2 has multiple conductor layers 23-23 to 23-28, and multiple through-hole conductors 24-18a to 24-22a and 24-18b to 24-22b that interconnect adjacent conductor layers 23. The through-hole conductor 24-21a is located in the middle of the conductor layer 23-26. The multiple conductor layers 23-23 to 23-28 are respectively disposed on the dielectric layers 10-23 to 10-28. The multiple conductor layers 23-23 to 23-28 are respectively wound along the plane of the dielectric layers 10-23 to 10-28. The through-hole conductors 24-18a to 24-22a and 24-18b to 24-22b enable the conductor layers 23-23 to 23-28 to be connected in series and form a spiral structure as a whole. Meanwhile, during the fabrication process, some through holes can be pre-set at any position on the conductor layer 23. When it is necessary to change the connection method, these through holes can be filled with conductive material to obtain the corresponding through-hole conductors 24, realizing multiple electrical connection schemes. For example, in this structure, other through-hole conductors 24 are reserved at the middle and end positions of the conductor layers 23-26, respectively. Figure 6 (The position corresponding to the dotted line in the middle circle) is reserved for the electrical connection method of other connecting conductor layers 23-26. The number of turns of each conductor layer 23-23 to 23-28 is less than 1 turn, but it can also be more than 1 turn.

[0065] To specifically verify the technical solution of the present invention, Examples 1-12 and Comparative Examples 1-7 are provided.

[0066] Example 1

[0067] An inductor product of model 0603 was manufactured according to the method of the present invention. The linewidth of its conductor layer 23, the dimensions of the through-hole conductor 24, and their relative positions were measured. Details of the measured linewidth of the conductor layer 23, the position and dimensions of the through-hole conductor 24 relative to the conductor layer 23, the shape of the through-hole conductor 24, the connection method of the conductor layer 23, and the distances of the coil conductor 2 from the upper surface 11 and the lower surface 12 are shown in Table 1. The manufacturing method includes the following steps:

[0068] S1. Screen printing is performed on a carrier using photosensitive insulating paste. The printed product is then exposed and cured to prepare the first insulating paste layer. The photosensitive insulating paste is a photosensitive ceramic paste, mainly composed of SiO2 and Al2O3 powder, specifically including the following components by mass percentage: alumina 14.85%, silicon dioxide 32.45%, boron oxide 4.4%, potassium oxide 3.3%, PMMA resin 40%, initiator triphenylphosphine oxide 0.5%, solvent diethylene glycol butyl ether 4%, and dispersant 0.5%.

[0069] S2. Print photosensitive conductive paste on the insulating paste layer, expose the printed product surface to cure the photosensitive conductive paste, and wash away the uncured paste after development. Here, a specific film is needed to mask the pattern during exposure to prepare the coil conductor pattern, resulting in the unsintered wire layer, the first end, the first external electrode base layer part and the second external electrode base layer part configured on the first insulating paste layer.

[0070] S3. Print photosensitive insulating material onto the product obtained in S2, expose and develop the photosensitive insulating material, and obtain through grooves and through holes connecting adjacent conductor layers on the printed product, which are configured with the first external electrode base layer and the second external electrode base layer in the first insulating paste layer. During exposure, a specific film is required for masking to obtain through grooves and through holes of the corresponding size. Fill the corresponding through grooves and through holes with photosensitive conductive paste to obtain the unsintered first external electrode base layer, the second external electrode base layer and the through hole conductor configured with the first insulating paste layer.

[0071] The exposure process parameters mentioned above include: the light source is mainly a mixed wavelength mercury lamp with a wavelength of 365nm, and the exposure time is 5s;

[0072] The development process mentioned above includes the following: rinsing and developing with 0.2% Na2CO3 developer, followed by rinsing with pure water and air blowing, and finally drying the surface water.

[0073] The photosensitive conductive paste in steps S2 and S3 has the same composition, specifically including the following components by mass percentage: 86% Ag powder, 10% PMMA resin, 0.5% initiator triphenylphosphine oxide, 3% solvent diethylene glycol butyl ether, and 0.5% dispersant.

[0074] S4. Prepare a second insulating paste layer on the product obtained in step 3, referring to the method of step S1;

[0075] S5. Following the steps of S2-S3, prepare the unsintered conductor layer, the first external electrode substrate layer, the second external electrode substrate layer, and the through-hole conductor on the second insulating slurry layer.

[0076] S6. Following the methods of steps S4-S5 above, an insulating slurry layer and its corresponding unsintered conductor layer, first external electrode base layer, second external electrode base layer, and through-hole conductor are sequentially stacked. A second end is configured on a portion of the last unsintered conductor layer to obtain a laminate. The completed laminate product is cut to a specific size. In this embodiment, the dimensions on the cutting equipment are set to a spacing of 0.74 mm on the X-axis and a spacing of 0.37 mm on the Y-axis. After cutting, sintering is performed to obtain a blank. Sintering process: Atmosphere: air; Total time: 237 min; Sintering temperature: 800℃; Maximum temperature holding time: 800℃ / 30 min.

[0077] S7. Electroplating is performed on the above blank at the positions corresponding to the first external electrode base layer and the second external electrode base layer to prepare the epitaxial layers of the first external electrode and the second external electrode, which together with the base layer constitute the complete first external electrode and the second external electrode, thus obtaining the inductor.

[0078] Examples 2-12 and Comparative Examples 1-7

[0079] The specific differences between Examples 2-12 and Comparative Examples 1-7 and Example 1 are shown in Table 1, while the rest are the same.

[0080] Table 1

[0081]

[0082]

[0083] The inductors prepared in the above embodiments and comparative examples were subjected to performance tests. The test methods and acceptance criteria are as follows:

[0084] 1. Inductance L and quality factor Q are measured using an E4991A.

[0085] 2. DC Resistance Test Method: Use an Aglient 4338B or equivalent device for measurement. Connect and clamp the device pins to both ends of the inductor. The DC resistance of the inductor is determined after the reading stabilizes. Acceptance Standard: The acceptance standard varies depending on the product specifications. Generally, the resistance should not exceed 0.1Ω per 1nH of inductance. Different manufacturers have different requirements for product specifications. For example, the inductors prepared in the embodiments and comparative examples of this invention are all model 0603. The 0.6nH inductance product requires a resistance of less than 0.06Ω, and the 120nH inductance product requires a resistance of less than 5Ω.

[0086] 3. Reliability Assessment - Short Circuit / Open Circuit Anomalies: During product manufacturing, due to deviations in the manufacturing process, some products may exhibit abnormal performance. Short circuit: When measuring the inductance value L, the value is smaller than the design value, or even close to 0. Open circuit: When measuring, there is no inductance value, or the value is negative, which is equivalent to a capacitor, and the DC resistance is extremely high. 1000 parallel products were tested for each example and comparative sample, and the percentage of reliability anomalies was calculated.

[0087] The performance test results are shown in Table 2.

[0088] Table 2

[0089] Number DC resistance rdc / Ω Inductance L / nH Quality factor Q Short open abnormality ratio Example 1 0.344 12.31 25.387 0％ Example 2 0.318 11.76 26.085 0％ Example 3 0.361 12.29 24.567 0％ Example 4 0.342 11.78 25.375 0％ Example 5 0.322 12.47 26.387 0％ Example 6 0.311 12.51 27.821 0％ Example 7 0.293 12.40 28.612 0％ Example 8 0.309 11.63 27.335 0％ Example 9 0.294 11.59 28.201 0％ Example 10 0.283 9.62 20.402 0％ Example 11 0.302 11.53 27.667 0％ Example 12 0.289 11.03 28.653 0％ Comparative Example 1 0.339 10.77 25.062 6％ Comparative Example 2 0.361 9.82 26.312 5％ Comparative Example 3 0.578 11.03 24.612 2％ Comparative Example 4 0.301 9.82 20.883 0％ Comparative Example 5 0.634 10.53 25.085 6％ Comparative Example 6 0.512 13.73 23.431 15％ Comparative Example 7 0.463 12.88 24.402 15％

[0090] As can be seen from Examples 1-2 and Comparative Examples 1-2, compared to the traditional method of connecting the via conductor to the conductive layer (e.g.) Figure 8 As shown, by designing the through-hole conductor and the conductor layer with a tangential connection, an inward bend in the connection point inside the inductor is achieved. This improves the problem of exposed connection points caused by cutting deviations, reduces the risk of exposed internal electrodes, and increases the usable area of ​​the coil conductor design. This increases the upper limit of the inductor's inductance design, reduces the inductor's resistance and short-circuit / open-circuit fault ratio, and improves the inductance L and quality factor Q, significantly improving its electrical performance and reliability. Furthermore, compared to Comparative Example 1, Example 1 shows a 9.14% increase in effective magnetic flux area and an 8.17% increase in the length of the coil conductor in each internal electrode layer; compared to Comparative Example 2, Example 2 shows a 4.69% increase in effective magnetic flux area and a 3.46% increase in the length of the coil conductor in each internal electrode layer.

[0091] As can be seen from Examples 1-2, 5-10 and Comparative Examples 3-5, the linewidth of the conductor layer and the diameter of the via conductor satisfy the following relationship: 10% ≤ (dw) / w ≤ 300%. More preferably, when w < 25 μm, 100% ≤ (dw) / w ≤ 300%; when w > 25 μm, 30% ≤ (dw) / w ≤ 150%. The inductor can balance low resistance and open-circuit fault ratio with high inductance L and quality factor Q, significantly improving its electrical performance and reliability.

[0092] As can be seen from Examples 1-2 and Comparative Examples 6-7, when L1≥20μm and L2≥20μm, the upper edge of the coil conductor is far from the upper and lower surfaces of the blank, that is, far from the edge of the blank. This can reduce the risk of exposed coil conductor, prevent the inner electrode from being exposed and causing electrical defects, and enable the inductor to have both low resistance and open circuit abnormality ratio and high quality factor Q, thus significantly improving its electrical performance and reliability.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An inductor, characterized in that, The device includes a blank formed by stacking multiple dielectric layers, a coil conductor disposed inside the blank, a first external electrode, and a second external electrode. The first and second external electrodes are disposed on the outer surface of the blank and electrically connected to the coil conductor. The blank has a lower surface, a first side surface connected to the lower surface, and a second side surface. The first external electrode is composed of a first lower portion disposed on the lower surface and a side portion disposed on the first side surface, and the first lower portion and the side portion of the first side surface are connected to each other. The second external electrode is composed of a second lower portion disposed on the lower surface and a side portion disposed on the second side surface, and the second lower portion and the side portion of the second side surface are connected to each other. The coil conductor includes multiple conductor layers and through-hole conductors connecting adjacent conductor layers. The conductor layers are disposed on multiple dielectric layers inside the blank and extend in the plane of the dielectric layers. The through-hole conductors penetrate the dielectric layers between adjacent conductor layers along the thickness direction of the dielectric layers. The conductor layers and the through-hole conductors are interconnected to form a three-dimensional spiral structure. Viewed from above in the stacking direction, the through-hole conductor protrudes inward toward the coil conductor, the outer edge of the through-hole conductor is tangent to the outer edge of the conductor layer, and the diameter d of the through-hole conductor is greater than the linewidth w of the conductor layer.

2. The inductor as described in claim 1, characterized in that, The coil conductor satisfies the following relationship: 10% ≤ (dw) / w ≤ 300%, where d is the diameter of the through-hole conductor and w is the linewidth of the conductor layer.

3. The inductor as described in claim 2, characterized in that, The coil conductor satisfies the following relationship: w < 25 μm, 100% ≤ (dw) / w ≤ 300%.

4. The inductor as described in claim 2, characterized in that, The coil conductor satisfies the following relationship: w > 25 μm, 30% ≤ (dw) / w ≤ 150%.

5. The inductor as described in claim 1, characterized in that, The blank also includes an upper surface opposite to the lower surface. When viewed from the stacking direction, the shortest distance between the outer edge of the coil conductor and the upper surface is L1, where L1 ≥ 20 μm.

6. The inductor as described in claim 5, characterized in that, The L1 is 20μm-70μm.

7. The inductor as claimed in claim 1, characterized in that, The shortest distance between the outer edge of the coil conductor and the lower surface is L2, where L2 ≥ 20 μm.

8. The inductor as claimed in claim 7, characterized in that, The L2 is 20μm-70μm.

9. The inductor as claimed in claim 1, characterized in that, Includes at least one of the following A and B: A. In the inductor, when two adjacent conductor layers are connected in series and / or in parallel, each conductor layer is provided with at least one through-hole conductor. B. Viewed from the stacking direction, the coil conductor includes a circular or regular polygonal through-hole conductor.

10. A method for manufacturing an inductor according to any one of claims 1-9, characterized in that, The preparation methods include the following: S1. Prepare the first insulating grout layer using insulating grout; S2. Photosensitive conductive silver paste is coated on the first insulating paste layer, and after exposure and development, an unsintered conductor layer, a portion of the first external electrode base layer and a portion of the second external electrode base layer, and an optional first end are formed in the configuration of the first insulating layer. S3. Coat the product obtained in step S2 with a photosensitive insulating material, and after exposure and development, form through holes corresponding to the through-hole conductors, as well as through grooves connecting the local parts of the first external electrode base layer and the local parts of the second external electrode base layer of the two adjacent layers. Fill the through grooves and through holes with a photosensitive conductive paste to form the unsintered first external electrode base layer, the base layer of the second external electrode, and the through-hole conductors arranged on the first insulating paste layer. S4. Following the steps S1-S3 above, a multilayer insulating paste layer and its corresponding unsintered conductive layer, first external electrode base layer, second external electrode base layer and through-hole conductor are stacked to obtain a laminate; optionally, a second end is prepared on the end of the last unsintered conductive layer. S5. The laminated body is cut and sintered to obtain a blank; S6. Electroplating is performed on the blank at positions corresponding to the first external electrode base layer and the second external electrode base layer to form a first external electrode epitaxial layer and a second external electrode epitaxial layer. The first external electrode base layer, the first external electrode epitaxial layer, the second external electrode base layer, and the second external electrode epitaxial layer respectively constitute a complete first external electrode and a second external electrode, thereby obtaining the inductor.

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