KR102749266B1 - Coil component - Google Patents

Abstract

A coil component according to one aspect of the present invention comprises: an insulating substrate; a coil portion arranged on at least one surface of the insulating substrate; and a body having an active portion on which the coil portion is arranged and a cover portion arranged on the active portion, the body embedding the insulating substrate and the coil portion; wherein a ratio of a thickness (T2) of the cover portion to a thickness (T1) of the insulating substrate satisfies 3<T2/T1<6, and a thickness (T2) of the cover portion satisfies 90㎛<T2<120㎛.

Description

COIL COMPONENT

The present invention relates to a coil component.

Inductor, one of the coil components, is a representative passive electronic component used in electronic devices along with resistors and capacitors.

As electronic devices become increasingly high-performance and thinner, coil components are also becoming thinner.

On the other hand, even if the coil component is thinned, there is a limit to reducing the thickness of the coil of the coil component because the coil component must secure appropriate inductance and direct current resistance (Rdc).

Accordingly, research is being conducted to reduce the thickness of the coil component by reducing at least one of the thickness of the external electrode, which is a component other than the coil, the thickness of the upper and lower covers respectively positioned at the upper and lower portions of the coil, and the thickness of the support substrate that supports the coil.

Korean Patent No. 10-1442402

The purpose of the present invention is to provide a coil component that can secure high inductance and low direct current resistance (Rdc) while being capable of being made thin (low-profile).

According to one aspect of the present invention, a coil component is provided, including: an insulating substrate; a coil portion arranged on at least one surface of the insulating substrate; and a body having an active portion on which the coil portion is arranged and a cover portion arranged on the active portion, the body burying the insulating substrate and the coil portion; wherein a ratio of a thickness (T2) of the cover portion to a thickness (T1) of the insulating substrate satisfies 3<T2/T1<6, and a thickness (T2) of the cover portion satisfies 90㎛<T2<120㎛.

According to another aspect of the present invention, a coil component is provided, including: a body; an insulating substrate embedded in the body; and a coil portion disposed on at least an upper surface of the insulating substrate; wherein a ratio of a distance (T2) from an upper surface of the coil portion to an upper surface of the body to a thickness (T1) of the insulating substrate satisfies 3<T2/T1<6, and a distance (T2) from an upper surface of the coil portion to an upper surface of the body satisfies 90㎛<T2<120㎛.

According to the present invention, it is possible to secure high-capacity inductance and low direct current resistance (Rdc) while making the coil component thin (low-profile).

FIG. 1 is a drawing schematically showing a coil component according to one embodiment of the present invention.
Figure 2 is a drawing showing a cross-section along line I-I' of Figure 1.
Figure 3 is a drawing showing a cross-section along line II-II' of Figure 1.

The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" and the like are intended to specify the presence of a feature, number, step, operation, component, part or a combination thereof described in the specification, but should be understood to not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof. In addition, throughout the specification, the term "on" means located above or below a target portion, and does not necessarily mean located on the upper side with respect to the direction of gravity.

In addition, the term “coupling” is used to refer not only to cases where each component is physically in direct contact with the other components in the contact relationship between each component, but also to cases where another component is interposed between each component and each component is in contact with the other component.

The size and thickness of each component shown in the drawing are arbitrarily shown for convenience of explanation, and therefore the present invention is not necessarily limited to what is shown.

In the drawing, the L direction can be defined as the first direction or length direction, the W direction can be defined as the second direction or width direction, and the T direction can be defined as the third direction or thickness direction.

Hereinafter, a coil component according to an embodiment of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the attached drawings, identical or corresponding components are assigned the same drawing numbers and redundant descriptions thereof are omitted.

Electronic devices use a variety of electronic components, and among these electronic components, a variety of coil components can be appropriately used for purposes such as noise removal.

That is, in electronic devices, coil components can be used as power inductors, high-frequency inductors (HF inductors), general beads, high-frequency beads (GHz beads), common mode filters, etc.

FIG. 1 is a drawing schematically showing a coil component according to one embodiment of the present invention. FIG. 2 is a drawing showing a cross-section along line I-I' of FIG. 1. FIG. 3 is a drawing showing a cross-section along line II-II' of FIG. 1.

Referring to FIGS. 1 to 3, a coil component (1000) according to one embodiment of the present invention includes a body (100), an insulating substrate (200), a coil portion (300), and external electrodes (400, 500), and may further include an insulating film (600).

The body (100) forms the overall appearance of the coil component (1000) according to the present embodiment, and has an insulating substrate (200) and a coil portion (300) embedded therein.

The body (100) can be formed in the shape of a hexahedron as a whole.

With reference to FIGS. 1 to 3, the body (100) includes a first surface (101) and a second surface (102) facing each other in the length direction (L), a third surface (103) and a fourth surface (104) facing each other in the width direction (W), and a fifth surface (105) and a sixth surface (106) facing each other in the thickness direction (T). Each of the first to fourth surfaces (101, 102, 103, 104) of the body (100) corresponds to a wall surface of the body (100) that connects the fifth surface (105) and the sixth surface (106) of the body (100). Hereinafter, both cross sections of the body (100) may refer to the first side (101) and the second side (102) of the body (100), both side surfaces of the body (100) may refer to the third side (103) and the fourth side (104) of the body (100), one side of the body (100) may refer to the sixth side (106) of the body (100), and the other side of the body (100) may refer to the fifth side (105) of the body (100). In addition, hereafter, the upper surface and the lower surface of the body (100) may refer to the fifth side (105) and the sixth side (106) of the body (100), respectively, defined based on the directions of FIGS. 1 to 3.

The body (100) may be formed so that the coil component (1000) according to the present embodiment, on which the external electrodes (400, 500) to be described later are formed, has a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.65 mm, but is not limited thereto. Alternatively, the body (100) may be formed so that the coil component (1000) according to the present embodiment, on which the external electrodes (400, 500) are formed, has a length of 2.0 mm, a width of 1.6 mm, and a thickness of 0.55 mm. Alternatively, the body (100) may be formed so that the coil component (1000) according to the present embodiment, on which the external electrodes (400, 500) are formed, has a length of 2.0 mm, a width of 1.2 mm, and a thickness of 0.55 mm. Alternatively, the body (100) may be formed so that the coil component (1000) according to the present embodiment, in which the external electrodes (400, 500) are formed, has a length of 1.2 mm, a width of 1.0 mm, and a thickness of 0.55 mm. However, the size of the coil component (1000) according to the present embodiment described above is merely exemplary, and therefore, a case in which the coil component is formed to have a size smaller than the above-described size is not excluded from the scope of the present invention.

The body (100) may include magnetic powder (P) and an insulating resin (R). Specifically, the body (100) may be formed by laminating one or more magnetic composite sheets including an insulating resin (R) and magnetic powder (P) dispersed in the insulating resin (R), and then curing the magnetic composite sheets. However, the body (100) may have a structure other than a structure in which magnetic powder (P) is dispersed in the insulating resin (R). For example, the body (100) may be made of a magnetic material such as ferrite.

The magnetic powder (P) may be, for example, ferrite or metal magnetic powder.

The ferrite powder may be, for example, at least one of spinel ferrites such as Mg-Zn, Mn-Zn, Mn-Mg, Cu-Zn, Mg-Mn-Sr, and Ni-Zn, hexagonal ferrites such as Ba-Zn, Ba-Mg, Ba-Ni, Ba-Co, and Ba-Ni-Co, garnet ferrites such as Y, and Li-based ferrites.

The metal magnetic powder may include at least one selected from the group consisting of iron (Fe), silicon (Si), chromium (Cr), cobalt (Co), molybdenum (Mo), aluminum (Al), niobium (Nb), copper (Cu), and nickel (Ni). For example, the metal magnetic powder may be at least one selected from the group consisting of pure iron powder, Fe-Si alloy powder, Fe-Si-Al alloy powder, Fe-Ni alloy powder, Fe-Ni-Mo alloy powder, Fe-Ni-Mo-Cu alloy powder, Fe-Co alloy powder, Fe-Ni-Co alloy powder, Fe-Cr alloy powder, Fe-Cr-Si alloy powder, Fe-Si-Cu-Nb alloy powder, Fe-Ni-Cr alloy powder, and Fe-Cr-Al alloy powder.

The metal magnetic powder may be amorphous or crystalline. For example, the metal magnetic powder may be, but is not necessarily limited to, an Fe-Si-B-Cr amorphous alloy powder.

The ferrite and metal magnetic powders may each have an average diameter of about 0.1 ㎛ to 30 ㎛, but are not limited thereto.

The body (100) may include two or more types of magnetic powders (P) dispersed in an insulating resin (R). Here, the fact that the magnetic powders (P) are of different types means that the magnetic powders (P) dispersed in the insulating resin (R) are distinguished from each other by any one of diameter, composition, crystallinity, and shape. For example, the body (100) may include two or more magnetic powders (P) having different diameters.

The insulating resin (R) may include, alone or in combination, epoxy, polyimide, liquid crystal polymer, etc., but is not limited thereto.

The body (100) includes a core (C) penetrating the coil portion (300) to be described later. The core (C) may be formed by, but is not limited to, filling the penetration hole of the coil portion (300) with at least a portion of the magnetic composite sheet during the process of laminating and curing the magnetic composite sheet.

The body (100) has an active part (110) and cover parts (120, 130) arranged on the active part (110). The active part (110) may refer to an area of the body (100) where the coil part (300) is arranged, and the cover parts (120, 130) may refer to an area of the body (100) arranged on the active part (110). As a non-limiting example, with reference to FIGS. 2 and 3, the active part (110) may refer to an area of the body (100) corresponding to the distance from the lower surface of the first coil pattern (311) to the upper surface of the second coil pattern (312), and the cover parts (120, 130) may be defined as other areas of the body (100) arranged on the first and second coil patterns (311, 312), respectively. The cover part (120, 130) may include an upper cover part (120) which is an upper side area of the body (100) and a lower cover part (130) which is a lower side area of the body (100), based on FIGS. 2 and 3.

The thickness (T2) of the upper cover part (120) is formed in a range exceeding 90 ㎛ and less than 120 ㎛. That is, the thickness (T2) of the upper cover part (120) satisfies 90 ㎛<T2<120 ㎛. When the thickness (T2) of the upper cover part (120) is 90 ㎛ or less, it is difficult to secure a high-capacity inductor, and when the thickness (T2) of the upper cover part (120) is 120 ㎛ or more, it is disadvantageous in reducing the thickness of the coil component. Meanwhile, the above-described description of the thickness (T2) of the upper cover part (120) can be similarly applied to the lower cover part (130).

As a non-limiting example, the active portion (110) may be formed to have a greater permeability than the permeability of the cover portion (120, 130). To this end, the magnetic powder (P) arranged in the active portion (110) may have a greater permeability than the magnetic powder (P) of the cover portion (120, 130). Alternatively or in parallel, the filling rate of the magnetic powder (P) of the active portion (110) may be greater than the filling rate of the magnetic powder (P) of the cover portion (120, 130).

An insulating substrate (200) is embedded in the body (100). The insulating substrate (200) is configured to support a coil portion (300) to be described later.

The insulating substrate (200) may be formed of an insulating material including a thermosetting insulating resin such as an epoxy resin, a thermoplastic insulating resin such as a polyimide, or a photosensitive insulating resin, or may be formed of an insulating material in which the insulating resin is impregnated with a reinforcing material such as glass fiber or an inorganic filler. For example, the insulating substrate (200) may be formed of an insulating material such as a prepreg, an Ajinomoto Build-up Film (ABF), a FR-4, a Bismaleimide Triazine (BT) film, a Photo Imagable Dielectric (PID) film, or the like, but is not limited thereto.

As an inorganic filler, at least one selected from the group consisting of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), silicon carbide (SiC), barium sulfate (BaSO ₄ ), talc, clay, mica powder, aluminum hydroxide (AlOH ₃ ), magnesium hydroxide (Mg(OH) ₂ ), calcium carbonate (CaCO ₃ ), magnesium carbonate (MgCO ₃ ), magnesium oxide (MgO), boron nitride (BN), aluminum borate (AlBO ₃ ), barium titanate (BaTiO ₃ ), and calcium zirconate (CaZrO ₃ ) can be used.

When the insulating substrate (200) is formed of an insulating material including a reinforcing material, the insulating substrate (200) can provide better rigidity. When the insulating substrate (200) is formed of an insulating material not including glass fiber, the insulating substrate (200) is advantageous in reducing the thickness of the entire coil portion (300). When the insulating substrate (200) is formed of an insulating material including a photosensitive insulating resin, the number of processes for forming the coil portion (300) is reduced, which is advantageous in reducing production costs, and allows the formation of fine vias.

The thickness (T1) of the insulating substrate (200) can be formed to be greater than 20 ㎛ and less than or equal to 30 ㎛. In other words, 20 ㎛<T1≤30 ㎛ can be satisfied. If the thickness (T1) of the insulating substrate (200) is less than or equal to 20 ㎛, it is difficult to secure the rigidity of the insulating substrate (200), making it difficult to support the coil part (300) to be described later during the manufacturing process. If the thickness (T1) of the insulating substrate (200) exceeds 30 ㎛, it is disadvantageous to reduce the thickness of the coil component.

The ratio of the thickness (T2) of the upper cover part (120) to the thickness (T1) of the insulating substrate (200) may be greater than 3 and less than 6. That is, 3<T2/T1<6 is satisfied. When the ratio of T2/T1 is 3 or less, the inductance may decrease. When the ratio of T2/T1 is 6 or more, the direct current resistance (Rdc) may increase.

The coil part (300) is embedded in the body (100) and exhibits the characteristics of the coil component. For example, when the coil component (1000) of the present embodiment is utilized as a power inductor, the coil part (300) can play a role in stabilizing the power of the electronic device by storing an electric field as a magnetic field and maintaining an output voltage.

The coil portion (300) includes coil patterns (311, 312) and a via (320). Specifically, with respect to the directions of FIGS. 1, 2, and 3, a first coil pattern (311) is arranged on the lower surface of an insulating substrate (200) facing the sixth surface (106) of the body (100), and a second coil pattern (312) is arranged on the upper surface of the insulating substrate (200). The via (320) penetrates the insulating substrate (200) and is contact-connected to the first coil pattern (311) and the second coil pattern (312), respectively. By doing so, the coil portion (300) can function as a single coil that forms one or more turns centered on the core (C).

Each of the first coil pattern (311) and the second coil pattern (312) may have a planar spiral shape forming at least one turn with the core (C) as an axis. For example, the first coil pattern (311) may form at least one turn with the core (C) as an axis on the lower surface of the insulating substrate (200).

At least one of the via (320) and the coil pattern (311, 312) may include one or more conductive layers. For example, when the second coil pattern (312) and the via (320) are formed by plating on the upper surface side of the insulating substrate (200), the second coil pattern (312) and the via (320) may each include a seed layer and an electrolytic plating layer. Here, the electrolytic plating layer may have a single-layer structure or a multi-layer structure. The electrolytic plating layer of the multi-layer structure may be formed as a conformal film structure in which one electrolytic plating layer is covered by another electrolytic plating layer, or may be formed in a shape in which another electrolytic plating layer is laminated on only one surface of one electrolytic plating layer. The seed layer may be formed by a method such as electroless plating or vapor deposition. In the former case, the seed layer may be formed by an electroless plating solution, but is not limited thereto. In the latter case, the seed layer may include at least one of titanium (Ti), chromium (Cr), nickel (Ni), and copper (Cu). The seed layer of the second coil pattern (312) and the seed layer of the via (320) may be formed integrally so that no boundary is formed therebetween, but is not limited thereto. The electroplated layer of the second coil pattern (312) and the electroplated layer of the via (320) may be formed integrally so that no boundary is formed therebetween, but is not limited thereto.

As another example, when a first coil pattern (311) disposed on the lower surface of an insulating substrate (200) and a second coil pattern (312) disposed on the upper surface of the insulating substrate (200) are formed separately from each other and then collectively laminated on the insulating substrate (200) to form a coil portion (300), the via (320) may include a high-melting-point metal layer and a low-melting-point metal layer having a melting point lower than the melting point of the high-melting-point metal layer. Here, the low-melting-point metal layer may be formed of a solder containing lead (Pb) and/or tin (Sn). At least a portion of the low-melting-point metal layer may be melted due to the pressure and temperature during the collective lamination, so that, for example, an intermetallic compound layer (IMC Layer) may be formed at the boundary between the low-melting-point metal layer and the second coil pattern (312).

Based on the directions of FIGS. 1 to 3, the coil patterns (311, 312) may be formed to protrude from both sides of the insulating substrate (200), respectively. As another example, the first coil pattern (311) may be formed to protrude from the lower surface of the insulating substrate (200), and the second coil pattern (312) may be embedded in the upper surface of the insulating substrate (200) such that the upper surface of the second coil pattern (312) is exposed to the upper surface of the insulating substrate (200). In this case, a concave portion may be formed on the upper surface of the second coil pattern (312), so that the upper surface of the second coil pattern (312) and the upper surface of the insulating substrate (200) may not be located on the same plane. As another example, the second coil pattern (312) may be formed to protrude on the upper surface of the insulating substrate (200), and the first coil pattern (311) may be embedded in the lower surface of the insulating substrate (200) so that the lower surface of the first coil pattern (311) may be exposed to the lower surface of the insulating substrate (200). In this case, a concave portion may be formed on the lower surface of the first coil pattern (311), so that the lower surface of the first coil pattern (311) and the lower surface of the insulating substrate (200) may not be located on the same plane.

Each of the via (320) and the coil pattern (311, 312) may be formed of a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), or an alloy thereof, but is not limited thereto.

The external electrodes (400, 500) are arranged on the surface of the body (100) and are respectively connected to both ends of the coil portion (300). In the present embodiment, the both ends of the coil portion (300) are respectively exposed to the first and second surfaces (101, 102) of the body (100). Accordingly, the first external electrode (400) is arranged on the first surface (101) and can be connected in contact with the end of the first coil pattern (311) exposed to the first surface (101) of the body (100), and the second external electrode (500) is arranged on the second surface (102) and can be connected in contact with the end of the second coil pattern (312) exposed to the second surface (103) of the body (100).

The external electrodes (400, 500) may be formed in a single-layer or multi-layer structure. For example, the first external electrode (400) may be composed of a first layer including copper, a second layer disposed on the first layer and including nickel (Ni), and a third layer disposed on the second layer and including tin (Sn). Here, the first to third layers may each be formed by plating, but are not limited thereto. As another example, the first external electrode (400) may include a resin electrode including conductive powder and resin, and a plating layer formed by plating on the resin electrode.

The external electrode (400, 500) may be formed of a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), or an alloy thereof, but is not limited thereto.

The insulating film (600) may be formed on the insulating substrate (200) and the coil portion (300). The insulating film (600) is for insulating the coil portion (300) from the body (100) and may include a known insulating material such as parylene. Any insulating material may be included in the insulating film (600), and there is no particular limitation. The insulating film (600) may be formed by a method such as vapor deposition, but is not limited thereto, and may be formed by laminating an insulating film on both sides of the insulating substrate (200). In the former case, the insulating film (600) may be formed in the form of a conformal film along the surfaces of the insulating substrate (200) and the coil portion (300). Meanwhile, in the present invention, the insulating film (600) is an optional configuration, so if the body (100) can secure sufficient insulation resistance under the operating conditions of the coil component (1000) according to the present embodiment, the insulating film (600) can be omitted.

(Experimental example)

Table 1 shows the changes in inductance (L) and DC resistance (Rdc) of Experimental Examples 1 to 8 according to changes in the thickness (T1) of the insulating substrate and the thickness (T2) of the upper cover.

Meanwhile, in all of the experimental examples 1 to 8 below, the coil part was manufactured to have the same number of turns. In addition, each turn of the coil part was manufactured to have the same width and thickness (height, for example, 140 μm for each of the first and second coil patterns), and the spacing between adjacent turns of the coil part was manufactured to be the same. Finally, the inductance (L) and DC resistance (Rdc) were measured at the same operating frequency.

T1(㎛) T2(㎛) T2/T1 L(Ref change) Rdc(Ref change) Whether it's thin or not # 1 30 60.0 2.00 60.2% 98.7% Park Hyung-hwa O #2 30 80.0 2.67 80.2% 99.1% Park Hyung-hwa O #3 30 195.0 6.50 116.4% 105.8% Park Hyunghwa X # 4 30 205.0 6.83 125.1% 106.0% Park Hyunghwa X # 5 30 90.0 3.00 82.5% 102.1% Park Hyung-hwa O #6 30 120.0 4.00 104.3% 102.6% Park Hyunghwa X #7 30 105.0 3.50 91.3% 102.3% Park Hyung-hwa O #8 30 115.0 3.83 100.3% 102.0% Park Hyung-hwa O

In Table 1, L (Ref change) was calculated with 0.47 mmH as the reference value and Rdc (Ref change) was calculated with 35 mΩ as the reference value, respectively. In Table 1, 'Whether thinning or not' indicates whether the thickness of the entire component formed up to the external electrode exceeds 0.60 mm. Therefore, if the thickness of the entire component exceeds 0.60 mm, it is marked as not thinning possible (thinning X) in Table 1. Referring to Table 1, in Experimental Examples 1, 2, and 5 where the ratio of T2/T1 is 3 or less, the inductance decreases compared to Experimental Examples 7 and 8 that satisfy 3 < T2/T1 < 6. For Experimental Examples 3 and 4 where the ratio of T2/T1 is 6 or more, the inductance increases compared to Experimental Examples 7 and 8 that satisfy 3<T2/T1<6, but the DC resistance (Rdc) increases and thinning is impossible. In addition, referring to Table 1, for Experimental Example 5 where T2 is 90㎛ or less, the inductance (L) decreases by more than 10% compared to Experimental Examples 7 and 8 that satisfy 90㎛<T2<120㎛. In the case of Experimental Example 6 where T2 is 120㎛ or more, thinning is impossible compared to Experimental Examples 7 and 8 which satisfy 90㎛<T2<120㎛. In conclusion, as shown in Table 1, in the case of Experimental Examples 7 and 8 which satisfy both 3<T2/T1<6 and 90㎛<T2<120㎛, thinning can be achieved while securing inductance (L).

Meanwhile, in the case of Experimental Example 7, the inductance decreases somewhat compared to the reference inductance, but is within the allowable range of 10% compared to the reference value.

By doing so, the coil component (1000) according to the present embodiment can implement high-capacity inductance and low direct current resistance (Rdc) while reducing the thickness of the coil component (1000).

Above, one embodiment of the present invention has been described, but it will be apparent to those skilled in the art that various modifications and changes to the present invention can be made by adding, changing, or deleting components, without departing from the spirit of the present invention as described in the claims, and this is also included within the scope of the rights of the present invention.

100: Body
110: Active part
120, 130: Cover part
200: Insulating board
300: Coil section
311, 312: Coil pattern
320: Via
400, 500: External electrode
600: Insulating film
C: Core
P: Magnetic powder
R: Insulating resin
1000: Coil Parts

Claims (6)

Insulating board;
A first coil pattern in a flat spiral shape arranged on one surface of the above insulating substrate,
A second coil pattern in a flat spiral shape arranged on the other side of the insulating substrate facing one side of the insulating substrate;
A body having a plurality of cover parts arranged to embed the insulating substrate and the first and second coil patterns;
The thickness of the above body is greater than 0㎛ and less than or equal to 550㎛,
The thickness of the above insulating substrate is greater than 20㎛ and less than 30㎛.
A coil component wherein the sum of the thicknesses of each of the first and second coil patterns is 160 ㎛ or more and 410 ㎛ or less.
In the first paragraph,
Further comprising a via penetrating the insulating substrate to connect the first coil pattern and the second coil pattern.
Coil components.
In the first paragraph,
The above body is a coil component including resin and magnetic powder.
In the first paragraph,
A coil component further comprising first and second external electrodes arranged on the surface of the body and connected to ends of the first and second coil patterns, respectively.
In paragraph 4,
A coil component having a thickness of more than 0㎛ and less than 600㎛.
In the first paragraph,
An insulating film disposed between the first and second coil patterns and the body and covering the first and second coil patterns;
A coil component further comprising: