Multilayer electronic components

Abstract

To provide a multilayer electronic component capable of suppressing flux inflow. [Solution] The stacked electronic component is a base body having a first main surface constituting a mounting surface, a second main surface facing the first main surface, and side surfaces adjacent to the first and second main surfaces, and comprises a base body having a plurality of particles P. The proportion of the gaps G between the plurality of particles P that occupy the first main surface or side surfaces is smaller than the proportion of the gaps G that occupy the second main surface.

Description

Technical Field

[0006] ,

[0007] ,

[0001] This disclosure relates to a multilayer electronic component.

Background Art

[0002] A multilayer electronic component having a body is known (see, for example, Patent Document 1). Patent Document 1 describes that by providing recesses on the main surface and the side surface of the body, the surface area of the body is increased and the heat dissipation of the inductor component is improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the inductor component is reflow soldered to an electronic device, the flux flows into the recesses provided on the main surface, which is the mounting surface, and the side surface adjacent to the mounting surface. As a result, the amount of flux relatively decreases, so the wettability of the solder decreases.

[0005] An object of this disclosure is to provide a multilayer electronic component capable of suppressing the inflow of flux.

Means for Solving the Problems

[0006] (1) A multilayer electronic component according to one aspect of this disclosure is a body having a first main surface constituting a mounting surface, a second main surface facing the first main surface, and side surfaces adjacent to the first main surface and the second main surface, the body including a body having a plurality of particles, and a ratio of a gap between the plurality of particles occupying the first main surface or the side surface being smaller than a ratio of the gap occupying the second main surface.

[0007] In the above-described stacked electronic component, the gaps on the first main surface, which is the mounting surface, and on the side surfaces adjacent to the first main surface are small, which helps to suppress flux inflow.

[0008] (2) In the stacked electronic component described in (1) above, the proportion of the gap that occupies the first main surface may be smaller than the proportion of the gap that occupies the second main surface. In this case, flux inflow can be suppressed more effectively.

[0009] (3) In the stacked electronic component described in (2) above, the proportion of the gap that occupies the side surface may be smaller than the proportion of the gap that occupies the second main surface. In this case, flux inflow can be reliably and effectively suppressed.

[0010] (4) In any one of the stacked electronic components described in (1) to (3) above, the surface roughness of the first main surface or the side surface may be less than the surface roughness of the second main surface. In this case, flux inflow can be suppressed.

[0011] (5) In any one of the stacked electronic components described in (1) to (4) above, the plurality of particles may be made of a material containing a soft magnetic metal. In this case, gaps tend to form between the plurality of particles, so a configuration that suppresses flux flow is effective. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide a stacked electronic component that can suppress flux inflow. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a perspective view showing one embodiment of a stacked electronic component. [Figure 2] Figure 2 shows the cross-sectional configuration of the stacked electronic component shown in Figure 1. [Figure 3] Figure 3 is a perspective view showing the configuration of the coil. [Figure 4]Figure 4 is a schematic plan view showing a magnified portion of the mounting surface. [Figure 5] Figure 5 is a schematic plan view showing a magnified portion of the side view. [Figure 6] Figure 6 is a schematic plan view showing a magnified portion of the top surface. [Modes for carrying out the invention]

[0014] Embodiments of this disclosure will be described in detail below with reference to the attached drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numeral, and redundant descriptions will be omitted.

[0015] The configuration of the multilayer electronic component 1 according to this embodiment will be described with reference to Figures 1 to 5. As shown in Figure 1, the multilayer electronic component 1 comprises a rectangular parallelepiped base body 2 and a pair of external electrodes 4, 4. The pair of external electrodes 4, 4 are positioned at both ends of the base body 2, respectively, and are spaced apart from each other. The rectangular parallelepiped shape includes a rectangular parallelepiped shape with chamfered corners and edges, and a rectangular parallelepiped shape with rounded corners and edges. The multilayer electronic component 1 is, for example, a coil component. The multilayer electronic component 1 can be applied to, for example, a bead inductor or a power inductor.

[0016] The rectangular parallelepiped body 2 has a pair of opposing sides 2a, 2a, a pair of opposing main faces 2b, 2c, and a pair of opposing sides 2d, 2d. Sides 2a, 2a are positioned adjacent to the pair of main faces 2b, 2c. Sides 2d, 2d are positioned adjacent to the pair of main faces 2b, 2c.

[0017] The main surface 2b (bottom surface in Figure 1) constitutes the mounting surface. The mounting surface is the surface that faces other electronic devices (circuit boards, electronic components, etc.) when mounting the multilayer electronic component 1 onto those other electronic devices. The main surface 2c (top surface in Figure 1) constitutes the mark surface on which a mark indicating the orientation of the base body 2 is provided. Note that the mark may also be provided on the sides 2a and 2d.

[0018] In this embodiment, the facing direction (first direction D1) of the pair of side surfaces 2a, 2a is the length direction of the body 2. The facing direction (second direction D2) of the pair of main surfaces 2b, 2c is the height direction of the body 2. The facing direction (third direction D3) of the pair of side surfaces 2d, 2d is the width direction of the body 2. The first direction D1, the second direction D2, and the third direction D3 are orthogonal to each other.

[0019] The length of the body 2 in the first direction D1 is greater than the lengths of the body 2 in the second direction D2 and the third direction D3. The length of the body 2 in the second direction D2 is equal to the length of the body 2 in the third direction D3. That is, in this embodiment, the pair of side surfaces 2a, 2a form a square shape, and the pair of main surfaces 2b, 2c and the pair of side surfaces 2d, 2d form rectangular shapes.

[0020] The length of the body 2 in the first direction D1 may be equal to the lengths of the body 2 in the second direction D2 and the third direction D3. The length of the body 2 in the second direction D2 may be different from the length of the body 2 in the third direction D3. "Equal" includes, in addition to being equal, minute differences or manufacturing errors within a preset range. For example, if a plurality of values are within the range of ±5% of the average value of the plurality of values, these values may be regarded as equal.

[0021] The pair of side surfaces 2a, 2a extend in the second direction D2 so as to connect the pair of main surfaces 2b, 2c. The pair of side surfaces 2a, 2a also extend in the third direction D3 so as to connect the pair of side surfaces 2d, 2d. The pair of main surfaces 2b, 2c extend in the first direction D1 so as to connect the pair of side surfaces 2a, 2a. The pair of main surfaces 2b, 2c also extend in the third direction D3 so as to connect the pair of side surfaces 2d, 2d. The pair of side surfaces 2d, 2d extend in the first direction D1 so as to connect the pair of side surfaces 2a, 2a. The pair of side surfaces 2d, 2d also extend in the second direction D2 so as to connect the pair of main surfaces 2b, 2c.

[0022] The base body 2 is constructed by stacking multiple magnetic material layers 11 (see Figure 3). Each magnetic material layer 11 is stacked in a direction opposite to the main surfaces 2b and 2c. That is, the stacking direction of each magnetic material layer 11 coincides with the opposite direction of the main surfaces 2b and 2c (hereinafter, the opposite direction of the main surfaces 2b and 2c will be referred to as the "stacking direction"). Each magnetic material layer 11 is roughly rectangular in shape. In the actual base body 2, each magnetic material layer 11 is integrated to such an extent that the boundaries between the layers are not visible.

[0023] As shown in Figures 2 and 3, a coil 15 is arranged inside the base body 2. The coil 15 contains a plurality of coil conductors 16 (16a to 16f). The plurality of coil conductors 16a to 16f contain a conductive material (for example, Ag or Pd). The plurality of coil conductors 16a to 16f are configured as a sintered body of a conductive paste containing a conductive material (for example, Ag powder or Pd powder).

[0024] The coil conductor 16a includes a connecting conductor 17. The connecting conductor 17 is positioned on one side 2a of the main body 2 and has an end exposed on that side 2a. The end of the connecting conductor 17 is exposed on one side 2a at a position closer to the main surface 2c and is connected to one of the external electrodes 4. That is, the coil 15 is electrically connected to one of the external electrodes 4 via the connecting conductor 17. In this embodiment, the conductor pattern of the coil conductor 16a and the conductor pattern of the connecting conductor 17 are formed integrally and continuously.

[0025] Multiple coil conductors 16a to 16f are formed within the base body 2 in the stacking direction of the magnetic layer 11. The multiple coil conductors 16a to 16f are arranged in the order of coil conductor 16a, coil conductor 16b, coil conductor 16c, coil conductor 16d, coil conductor 16e, and coil conductor 16f. In this embodiment, the coil 15 is composed of the portion of coil conductor 16a other than the connecting conductor 17, the multiple coil conductors 16b to 16d, and the portion of coil conductor 16f other than the connecting conductor 18.

[0026] The ends of the coil conductors 16a to 16f are connected by through-hole conductors 19a to 19e. The coil conductors 16a to 16f are electrically connected to each other by the through-hole conductors 19a to 19e. The coil 15 is constructed by electrically connecting multiple coil conductors 16a to 16f. Each through-hole conductor 19a to 19e contains a conductive material (e.g., Ag or Pd). Each through-hole conductor 19a to 19e, like the multiple coil conductors 16a to 16f, is constructed as a sintered body of a conductive paste containing a conductive material (e.g., Ag powder or Pd powder).

[0027] The external electrode 4 is positioned to cover the end of the base body 2 on the side surface 2a. As shown in Figure 1, the external electrode 4 has an electrode portion 4a that covers the side surface 2a, electrode portions 4b and 4c that protrude onto a pair of main surfaces 2b and 2c, and electrode portions 4d and 4d that protrude onto a pair of side surfaces 2d and 2d. In other words, the external electrode 4 is formed by five surfaces consisting of electrode portions 4a, 4b, 4c, 4d and 4d.

[0028] The electrode portion 4a is positioned to cover the entire ends of the connecting conductors 17 and 18 exposed on the side surface 2a, and the connecting conductors 17 and 18 are directly connected to the external electrode 4. In other words, the connecting conductors 17 and 18 connect the ends of the coil 15 to the electrode portion 4a. As a result, the coil 15 is electrically connected to the external electrode 4.

[0029] The adjacent electrode portions 4a, 4b, 4c, 4d, and 4d are continuous and electrically connected at the edges of the base body 2. Electrode portion 4a and electrode portion 4b are connected at the edge between the side surface 2a and the main surface 2b. Electrode portion 4a and electrode portion 4c are connected at the edge between the side surface 2a and the main surface 2c. Electrode portion 4a and electrode portion 4d are connected at the edge between the side surface 2a and the side surface 2d.

[0030] The external electrode 4 is composed of a conductive material. The conductive material is, for example, Ag or Pd. The external electrode 4 is a baked electrode and is composed of a sintered body of conductive paste. The conductive paste contains conductive metal powder and glass frit. The conductive metal powder is, for example, Ag powder or Pd powder. A plating layer is formed on the surface of the external electrode 4. The plating layer is formed, for example, by electroplating. The electroplating is, for example, electroplated Ni or electroplated Sn.

[0031] Next, we will explain the configuration of the aforementioned base model 2 in more detail.

[0032] Figure 4 is a schematic plan view showing an enlarged portion of the mounting surface (main surface 2b) as viewed from a direction perpendicular to the mounting surface. Figure 5 is a schematic plan view showing an enlarged portion of the side surface (side surface 2d) as viewed from a direction perpendicular to the side surface. Figure 6 is a schematic plan view showing an enlarged portion of the top surface (main surface 2c) as viewed from a direction perpendicular to the top surface. As shown in Figures 4 to 6, the element 2 contains a plurality of particles P. The plurality of particles P consist of a magnetic material, for example, a soft magnetic metal. Examples of such magnetic materials include soft magnetic alloys such as Fe-Si alloys. Fe-Si alloys may also contain P. Soft magnetic alloys may also be, for example, Fe-Ni-Si-M alloys. "M" contains one or more elements selected from Co, Cr, Mn, P, Ti, Zr, Hf, Nb, Ta, Mo, Mg, Ca, Sr, Ba, Zn, B, Al, and rare earth elements. The multiple particles P may consist of a magnetic material containing ferrite, or they may consist of a dielectric material.

[0033] In substrate 2, particles P,P are bonded to each other. This bonding is achieved, for example, by the bonding of oxide films formed on the surface of the particles P. Substrate 2 includes a resin-filled portion. The resin is present in at least some of the spaces between multiple particles P,P. The resin is an electrically insulating resin. Examples of resins used include silicone resin, phenolic resin, acrylic resin, epoxy resin, etc. There may be voids between multiple particles P,P that are not filled with resin.

[0034] Multiple particles P are exposed on the surface of the base body 2. Gaps G exist between the multiple particles P exposed on the surface of the base body 2. The proportion of gap G that occupies the main surface 2b is smaller than the proportion that occupies the main surface 2c. The proportion that occupies the pair of sides 2d, 2d is smaller than the proportion that occupies the main surface 2c. Although the plan view of the pair of sides 2a, 2a is omitted, the proportion that occupies the pair of sides 2a, 2a is equivalent to the proportion that occupies the pair of sides 2d, 2d. That is, the proportion that occupies the pair of sides 2a, 2a is smaller than the proportion that occupies the main surface 2c. The proportion that occupies the pair of sides 2a, 2a may differ from the proportion that occupies the pair of sides 2d, 2d.

[0035] The proportion of the gap G on the pair of sides 2a, 2a and the pair of sides 2d, 2d is smaller than the proportion of the gap G on the main surface 2b. The pair of sides 2a, 2a and the pair of sides 2d, 2d are surfaces formed by cutting with a dicing blade. Each particle P on the pair of sides 2a, 2a and the pair of sides 2d, 2d has the characteristic of being stretched in the cutting direction and having a larger area compared to each particle P on the main surface 2b. The cutting direction is the tangential direction of the dicing blade. The cutting direction of side 2d is the first direction D1, and the cutting direction of side 2a is the third direction D3.

[0036] The proportion of each surface of the element 2 occupied by gaps G can be measured, for example, as follows: First, each surface of the element 2 is observed with a scanning electron microscope (SEM) from a direction perpendicular to the surface, and an SEM image is obtained. Next, the obtained SEM image is analyzed to identify particles P and gaps G. Particles P and gaps G can be identified by the difference in contrast in the image. Finally, the area ratio of gaps G is calculated, and this value is taken as the proportion of the surface occupied by gaps G.

[0037] The surface roughness of the main surface 2b is less than that of the main surface 2c. The surface roughness of the pair of sides 2a, 2a and the pair of sides 2d, 2d is less than that of the main surface 2c. The surface roughness of the pair of sides 2a, 2a and the pair of sides 2d, 2d are equal to, but may be different. The surface roughness of the pair of sides 2a, 2a and the pair of sides 2d, 2d is less than that of the main surface 2b. Surface roughness is, for example, arithmetic mean roughness (Ra).

[0038] The manufacturing method for the base body 2 will be explained.

[0039] First, a laminated green substrate is prepared, comprising multiple stacked magnetic green sheets and a conductive paste film that serves as an internal conductor. The magnetic green sheets are formed, for example, by applying a magnetic slurry containing multiple particles P, an insulating resin, and a solvent onto a substrate (e.g., a PET film) using a screen printing method or a doctor blade method. For the bottom layer of the laminated green substrate (i.e., the layer having the main surface 2b), a magnetic green sheet is used that has been calendered to eliminate the gaps G between the particles P. The conductive paste film is formed in the shape of a corresponding magnetic green sheet, for example, by a plating method or a screen printing method.

[0040] Next, the laminated green substrate is cut into chips of a predetermined size using a dicer equipped with a rotating blade, forming multiple individual laminates. The cutting surfaces made by the rotating blade are the surfaces that become a pair of sides 2a, 2a and a pair of sides 2d, 2d. By adjusting the dicing conditions, the state of the particles P and gaps G on the cutting surface can be adjusted. For example, the faster the rotation speed of the rotating blade, the more the particles P deform and the more the gaps G are compressed.

[0041] Next, the individualized laminates are fired. Then, a conductive paste is applied to the outer surface of the fired laminates and heat treatment is performed to bake the conductive paste onto the laminates, forming the external electrodes 4. Subsequently, the fired laminates are immersed in a resin liquid to impregnate the laminates with resin, and then the resin on the surface of the laminates is washed off with toluene. By washing, gaps are formed on the surface of the laminates. Next, the resin impregnated into the laminates is cured by heat to form the base body 2. Subsequently, plating may be applied to the external electrodes 4. Through the above steps, a laminated electronic component 1 is obtained.

[0042] As explained above, in the stacked electronic component 1, there are small gaps on the main surface 2b and on each side surface 2a and 2d. Since the main surface 2b is the mounting surface, the small gaps on the main surface 2b prevent the flux of the solder applied to the mounting surface from flowing into the gaps. Since each side surface 2a and 2d is adjacent to the mounting surface, solder may wrap around from the mounting surface to the area of ​​each side surface 2a and 2d on the mounting surface side. Even in this case, the small gaps on each side surface 2a and 2d prevent the flux from flowing into the gaps. As a result, the amount of flux is relatively reduced, and the decrease in solder wettability is suppressed. In particular, since external electrodes 4 are formed on the side surfaces 2a and 2d, a configuration that suppresses flux flow is effective.

[0043] Since the multiple particles P are made of a material containing a soft magnetic metal, gaps are more likely to form between the multiple particles P compared to, for example, a case where the multiple particles P are made of a ferrite material. Therefore, a configuration that suppresses flux flow is particularly effective.

[0044] Although embodiments have been described above, the present invention is not necessarily limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. The embodiments and modifications described above may be combined as appropriate. [Explanation of Symbols]

[0045] 1...Stacked electronic component, 2...Element, 2a...Side, 2b...Main surface, 2c...Main surface, 2d...Side, 4...External electrode, 11...Magnetic layer, 15...Coil, G...Gap, P...Particle.

Claims

1. A substrate having a first main surface constituting a mounting surface, a second main surface facing the first main surface, and a side surface adjacent to the first main surface and the second main surface, comprising a substrate having a plurality of particles, The proportion of the gaps between the plurality of particles that occupy the first main surface or the side surface is smaller than the proportion of the gaps that occupy the second main surface. Stacked electronic components.

2. The proportion of the gap that occupies the first main surface is smaller than the proportion of the gap that occupies the second main surface. The stacked electronic component according to claim 1.

3. The proportion of the gap that occupies the side surface is smaller than the proportion of the gap that occupies the second main surface. The stacked electronic component according to claim 2.

4. The surface roughness of the first main surface or the side surface is less than the surface roughness of the second main surface. A stacked electronic component according to any one of claims 1 to 3.

5. The plurality of particles are made of a material containing a soft magnetic metal. A stacked electronic component according to any one of claims 1 to 3.

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