Electronic Components

Abstract

To provide an electronic component that can increase the ratio of a conductor occupying the thickness in the interlayer direction.SOLUTION: The electronic component includes a first circuit pattern 20a and a second circuit pattern 20b stacked in this order from the bottom to the top in the interlayer direction and an insulator 22 arranged between the first circuit pattern and the second circuit pattern. The second circuit pattern is shaped such that its width Wa, a dimension perpendicular to the interlayer direction, narrows as a lower the edge 20A is located lower in the interlayer direction in the cross-sectional view of a cross-section including the interlayer direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electronic component and a method for manufacturing an electronic component. [Background technology]

[0002] Conventionally, multilayer electronic components have been known that include a laminate in which insulating layers and conductor layers are stacked, and the laminate includes vias that electrically connect a lower conductor layer and an upper conductor layer. Patent Documents 1 and 2 disclose methods for manufacturing such multilayer electronic components.

[0003] The manufacturing method shown in Patent Document 1 is as follows. First, a conductor pattern made of copper foil or the like is formed on the entire surface of one side of each of a first insulating substrate made of thermoplastic resin and a third insulating substrate. Next, through holes are formed in predetermined locations of a second insulating substrate made of thermoplastic resin by laser processing, etching, or the like, and these through holes are filled with a conductive paste. Then, the first insulating substrate with the conductor pattern facing downward is used as the top layer, and a second insulating substrate and a third insulating substrate with the conductor pattern facing upward are stacked in this order. The first insulating substrate, second insulating substrate, and third insulating substrate are then integrated by hot pressing. During this hot pressing, the conductive paste in the through holes hardens, forming vias.

[0004] The manufacturing method shown in Patent Document 2 is as follows. First, a groove is formed on the surface of the first insulating layer by photolithography. Next, a conductive paste is applied to the groove to form a coil conductor layer in the groove. Next, an insulating paste is applied to the first insulating layer and the coil conductor layer by screen printing to form a second insulating layer, and a via conductor layer is formed in this second insulating layer. These steps are then repeated multiple times to form a laminate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6424453 [Patent Document 2] Japanese Patent Publication No. 2020-194976 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional manufacturing method has the following problems. The laminate obtained by the manufacturing method of Patent Document 1 has a so-called sandwich structure in which the surface of the first insulating substrate on which the conductor pattern is formed and the surface of the third insulating substrate on which the conductor pattern is formed face each other across the second insulating substrate. Therefore, although the manufacturing method of Patent Document 1 can narrow the gap between two opposing conductor patterns, increasing the number of layers further requires stacking via an insulating substrate, making it impossible to narrow the gap between the conductor patterns via the insulating substrate. Therefore, it is not possible to increase the proportion of the conductor pattern in the thickness of the electronic component in the interlayer direction.

[0007] In the manufacturing method of Patent Document 2, if the coil conductor layer formed on the first insulating layer protrudes from the groove, and the second insulating layer laminated on the first insulating layer is thin, the second insulating layer will bulge at the portion of the coil conductor layer, causing the second insulating layer to have a wavy shape in a cross-sectional view including the interlayer direction, which will interfere with the formation of other layers on the second insulating layer. For this reason, the second insulating layer must be thick enough to absorb the protrusion of the coil conductor layer formed on the first insulating layer, and there is a limit to how thin the second insulating layer can be, so the proportion of the coil conductor layer in the thickness of the electronic component in the interlayer direction cannot be increased.

[0008] An object of the present invention is to provide an electronic component that can increase the proportion of conductors in the thickness in the interlayer direction. [Means for solving the problem]

[0009] One aspect of the present invention comprises a first circuit pattern and a second circuit pattern stacked in this order from bottom to top in an interlayer direction, and an insulator arranged between the first circuit pattern and the second circuit pattern, wherein the second circuit pattern has a shape in which a lower end portion in the interlayer direction is narrower as it is positioned lower in the interlayer direction in a cross-sectional view of a cross section including the interlayer direction, and the lower end portion of the second circuit pattern in the interlayer direction is positioned lower in the interlayer direction than an upper end portion of the first circuit pattern in the interlayer direction in a cross-sectional view of the cross section including the interlayer direction. wherein the first circuit pattern and the second circuit pattern are directly joined and electrically connected without a via. It is an electronic component. [Effects of the Invention]

[0010] According to the present invention, the proportion of the conductor in the thickness in the interlayer direction can be increased. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing the internal structure of a coil component according to a first embodiment of the present invention. [Figure 2] 4A and 4B are enlarged cross-sectional views of a second circuit pattern and a via in a cross section including an interlayer direction of the laminate. [Figure 3] 1A to 1C are diagrams illustrating an example of a manufacturing process for a coil component. [Figure 4] 1A to 1C are diagrams illustrating processing steps in an exposure and development process. [Figure 5] FIG. 1 illustrates scattering, diffraction, and reflection of light within an insulating material. [Figure 6] 1A to 1C are diagrams illustrating a process for forming a trench having a curved portion. [Figure 7] FIG. 10 is a diagram showing the relationship between the development time and the shape of the trench for the second circuit pattern. [Figure 8] FIG. 10 is a diagram showing the relationship between the focal position of exposure light and the shape of a trench. [Figure 9] FIG. 6 is a schematic diagram of the internal structure of a coil component according to a second embodiment of the present invention. [Figure 10]FIG. 2 is a diagram showing a wiring topology of a coil body in a coil component. [Figure 11] 1A to 1C are diagrams illustrating an example of a manufacturing process for a coil component. [Figure 12] FIG. 4 is a schematic diagram showing the configuration of a laminate according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a coil component will be described as an example of a multilayer electronic component. Note that the drawings may include schematic diagrams in part. Also, the dimensions and ratios in the schematic diagrams may differ from the actual values.

[0013] [First embodiment] FIG. 1 is a schematic diagram of the internal structure of a coil component 1 according to this embodiment. The coil device 1 includes a first circuit pattern 20a and a second circuit pattern 20b stacked in one direction on the plane of a support plate 3 made of an insulating material, and an insulator 22 made of an insulating material disposed between the first circuit pattern 20a and the second circuit pattern 20b. The first circuit pattern 20a, the second circuit pattern 20b, and the insulator 22 form a laminate 10. A pair of external electrodes (not shown) is provided on the surface of the laminate 10.

[0014] Here, the direction in which the first circuit pattern 20a and the second circuit pattern 20b are stacked is defined as the interlayer direction (also referred to as the interlayer direction) and is denoted by the symbol Z. Furthermore, a plane perpendicular to the interlayer direction Z is defined as the XY plane. The X direction of the XY plane corresponds to the left-right direction in the drawing, and the Y direction corresponds to the depth direction in the drawing.

[0015] Furthermore, in this specification, the terms "upper," "lower," "left," and "right" used for the interlayer direction Z, the X direction, and the Y direction are used for convenience based on the drawings to distinguish relative directions, and do not correspond to the vertical and horizontal directions that indicate absolute directions, or to directions based on the posture of the electronic component when mounted or in use. Hereinafter, the direction of the support plate 3 along the interlayer direction will be referred to as the "lower side," and the opposite side will be referred to as the "upper side."

[0016] The first circuit pattern 20a and the second circuit pattern 20b extend along the XY plane, and a portion of the first circuit pattern 20a and a portion of the second circuit pattern 20b are electrically connected to each other by vias 24 to form a wound coil body.

[0017] The coil component 1 may include the laminate 10 in a part thereof. That is, in a cross-sectional view of a cross section including the interlayer direction Z, the entire cross section of the coil component 1 does not need to have the structure of the laminate 10 shown in Fig. 1, but it is sufficient that the structure of the laminate 10 is included in a part of the cross section.

[0018] The insulator 22 is primarily made of an insulating material and is a main component of the base body of the coil device 1. That is, the coil device 1 has a structure in which the above-described coil body is embedded inside an insulating base body made of the insulator 22.

[0019] In this embodiment, the insulating material constituting the insulator 22 is, for example, a sintered glass. The glass is formed, for example, by firing a glass paste in which glass powder is mixed with a photosensitive insulating resin, and a filler material primarily composed of aluminum oxide (Al2O3) is also added to ensure the strength of the element. Since the insulator 22 made of such an insulating material is also nonmagnetic, the coil component 1 has a high quality factor (Q) and reduced magnetic loss, making it suitable for various circuits for high-frequency signals in the gigahertz band, wireless communication circuits, and the like. However, the insulating material constituting the insulator 22 is not limited to glass or a nonmagnetic material, and may be other sintered materials such as alumina or ferrite, a nonmagnetic resin, or a hardened resin containing magnetic powder.

[0020] The support plate 3 is a layer whose main component is an insulating material, similar to the insulator 22, and is made of the same insulating material. The support plate 3 and the insulator 22 are integrated as an area of ​​insulating material. Note that the support plate 3 need only be a layer on whose main surface the first circuit pattern 20a is formed, and does not need to actually have a supporting function or the strength required to ensure that function. The support plate 3 may also have a multi-layer structure, and some of the multiple layers may be colored to provide a marker function.

[0021] The first circuit pattern 20a, the second circuit pattern 20b, and the vias 24 are formed of a conductive material. In this embodiment, the conductive material is a metal such as silver (Ag), copper (Cu), gold (Au), aluminum (Al), or an alloy containing any of these as a main component. The metal may be a sintered conductive paste made by mixing metal powder with resin, or may be formed by a thin film method.

[0022] 2 is an enlarged view of the second circuit pattern 20b and the via 24 in a cross-sectional view of the laminate 10, the cross-section including the interlayer direction Z. Hereinafter, the cross-section including the interlayer direction Z will be referred to as the "interlayer direction cross-section." The interlayer direction cross-section is a cross-section that intersects the extension direction of the second circuit pattern 20b and passes through the center of the via 24. If the coil component 1 has a structure in which such a cross-section cannot be obtained, a cross-section of the second circuit pattern 20b and a cross-section that passes through the center of the via 24 can be obtained separately, and each can be used as the interlayer direction cross-section.

[0023] As shown in the figure, the coil component 1 includes a first circuit pattern 20a and a second circuit pattern 20b stacked in this order from bottom to top in the interlayer direction Z, and an insulator 22 disposed between the first circuit pattern 20a and the second circuit pattern 20b. That is, the upper side in the interlayer direction Z is the direction from the first circuit pattern 20a to the second circuit pattern 20b, and the lower side in the interlayer direction Z is the direction from the second circuit pattern 20b to the first circuit pattern 20a.

[0024] As described above, the coil device 1 further includes a via 24 that electrically connects the first circuit pattern 20a and the second circuit pattern 20b. In an interlayer direction cross-sectional view, the outer shapes of the second circuit pattern 20b and the via 24 include curved portions 52 and 53. These curved portions 52 and 53 are formed at the lower ends 20A and 24A of the second circuit pattern 20b and the via 24 in the interlayer direction Z. Due to these curved portions 52 and 53, the second circuit pattern 20b and the via 24 have shapes in which the widths Wa and Wb in the X direction, which are dimensions perpendicular to the interlayer direction, become narrower as the lower ends in the interlayer direction are positioned lower in the interlayer direction in a cross-sectional view including the interlayer direction. The width Wa is the dimension perpendicular to the interlayer direction of the second circuit pattern 20b in the interlayer direction cross-sectional view, and the width Wb is the dimension perpendicular to the interlayer direction of the via 24 in the interlayer direction cross-sectional view.

[0025] That is, the lower end of the second circuit pattern 20b in the interlayer direction Z is curved, which improves adhesion with the insulator 22, which is relatively thin at the bottom of the second circuit pattern 20b, and prevents peeling between the second circuit pattern 20b and the insulator 22.

[0026] Furthermore, a portion 51, which is the upper end portion of the first circuit pattern 20a in the interlayer direction Z, on the opposite side from the curved portion 52 in the interlayer direction Z, is substantially linear in the X direction, and the via 24 is connected to the substantially linear portion 51. That is, the upper ends of the first circuit pattern 20a and the second circuit pattern 20b in the interlayer direction Z are planar, which increases the cross-sectional areas of the first circuit pattern 20a and the second circuit pattern 20b and reduces the DC electrical resistance. Note that in this embodiment, as shown in FIG. 1, the lower end portion of the first circuit pattern 20a in the interlayer direction Z is also planar, which can further reduce the DC electrical resistance of the first circuit pattern 20a.

[0027] In this embodiment, the maximum value of the width Wb of the via 24 is smaller than the maximum value of the width Wa of the second circuit pattern 20b, and a step shape is formed at the connection portion 17 between the second circuit pattern 20b and the via 24.

[0028] In this way, by having the second circuit pattern 20b and the via 24 have shapes in which the widths Wa and Wb narrow in the interlayer direction Z, it is possible to increase the proportion of the conductors (i.e., the first circuit pattern 20a and the second circuit pattern 20b) in the thickness in the interlayer direction Z, as described below, compared to when the widths Wa and Wb are approximately constant. Furthermore, by having the second circuit pattern 20b and the via 24 have the above shapes, a structure is formed in which the insulating material of the insulator 22 infiltrates around the end 20A of the second circuit pattern 20b and the end 24A of the via 24, respectively, thereby improving the adhesion between the layers in the laminate 10. In particular, the stepped shape of the connection portion 17 further improves the adhesion.

[0029] In the laminate 10 of this embodiment, the thickness of the insulator 22 in the interlayer direction Z below the second circuit pattern 20b is 1 μm or more and 5 μm or less. In a cross-sectional view in the interlayer direction, the width of the second circuit pattern 20b in the X direction is 10 μm or more and 30 μm or less, and the thickness in the interlayer direction Z is 10 μm or more and 30 μm or less. Regarding the overall dimensions of the coil component 1, the longitudinal dimension is preferably 1.0 mm or less, particularly 0.4 mm or less. The interlayer dimension is preferably 0.5 mm or less, particularly 0.2 mm or less. Furthermore, the dimension in the direction perpendicular to both the longitudinal direction and the interlayer direction is preferably 0.5 mm or less, particularly 0.2 mm or less.

[0030] Next, a method for manufacturing the coil component 1 according to this embodiment will be described in detail. 3A to 3C are diagrams illustrating an example of a manufacturing process for the coil device 1. In each diagram illustrating a cross section, hatching does not clearly indicate the cross section, but indicates that the photosensitive glass paste (insulating material) is in an uncured state. First, a first circuit pattern 20a of a first layer is formed on a flat surface, i.e., on the upper surface of the support board 3, by printing a conductive paste and drying the conductive paste (step Sa1). Step Sa1 corresponds to the first step of forming a first circuit pattern on a flat surface in the present disclosure.

[0031] Next, insulating material 25, which is a photosensitive glass paste that will become insulators 22, is printed on upper surface 3A of support plate 3 so as to cover first circuit pattern 20a, and then insulating material 25 is dried (step Sa2). Step Sa2 corresponds to the second step in this disclosure of forming a photosensitive insulating material so as to cover the first circuit pattern. Steps Sa1 and Sa2 form first circuit pattern 20a embedded in insulator 22.

[0032] Next, a process for forming the second circuit pattern 20b and the vias 24 is carried out. Specifically, first, trenches 62 for the second circuit pattern and trenches 63 for vias are formed on the surface of insulating material 25 by performing an exposure and development process (described later) (step Sa3). Step Sa3 corresponds to the third step in the present disclosure, in which trenches for the second circuit pattern are formed by exposing and developing the surface of the insulating material.

[0033] The second circuit pattern trench 62 is a groove formed to a depth Da that does not reach the first circuit pattern 20a, that is, a depth Da that ensures that a predetermined thickness of the insulator 22 is obtained between the trench 62 and the first circuit pattern 20a. On the other hand, the via trench 63 is a through-hole formed in the bottom of a portion of the second circuit pattern trench 62, penetrating the insulator 22 and reaching the underlying first circuit pattern 20a. Hereinafter, the predetermined thickness of the insulator 22 below the second circuit pattern 20b will be referred to as the "interlayer distance α." The total depth Db of the second circuit pattern trench 62, including the via trench 63 at its bottom, is the sum of the depth Da of the second circuit pattern trench 62 and the interlayer distance α.

[0034] Furthermore, the trench 62 for the second circuit pattern and the trench 63 for the via formed in step Sa3 include, in a cross-sectional view in the interlayer direction, curved portions 62A and 63A at their bottoms that correspond to the curved portions 52 and 53. That is, in step Sa3, which is the third step, the trench 62 for the second circuit pattern has a bottom whose width Wa, which is the dimension perpendicular to the interlayer direction, narrows as it goes deeper along the interlayer direction, which is the direction in which the first circuit pattern 20a and the second circuit pattern 20b are stacked.

[0035] In this way, in the exposure and development process of step Sa3, the second circuit pattern trench 62 and the via trench 63, which have different depths Da and Db and include curved portions 62A and 63A, are formed in the same processing step, thereby simplifying the processing steps. This exposure and development process will be described later.

[0036] Next, conductive paste is filled into the second circuit pattern trench 62 and the via trench 63 by printing, and the conductive paste is dried (step Sa4), thereby forming the second circuit pattern 20b and the via 24. Step Sa4 corresponds to the fourth step in the present disclosure of filling the second circuit pattern trench with a conductive material to form the second circuit pattern.

[0037] Thereafter, the laminate 10 is fired under predetermined conditions, followed by barrel processing, and external electrodes are provided on the surfaces of the laminate 10, which are then plated with tin (Sn), nickel (Ni), or the like, to complete the multilayer coil component 1. However, the external electrodes may also be formed inside the laminate 10 (i.e., inside the insulating material 25) simultaneously with the second circuit pattern 20b. The printing in steps Sa1 to Sa4 can be performed by screen printing or inkjet printing, and in this embodiment, screen printing is used.

[0038] According to the manufacturing method of this embodiment, the depth of the trench 62 for the second circuit pattern formed in the insulating material 25 can be precisely controlled using photolithography, so that the thickness of the insulating material 25 between the second circuit pattern 20b and the first circuit pattern 20a can be controlled to be thin, thereby increasing the proportion of the first circuit pattern 20a and the second circuit pattern 20b, which are conductors, in the overall interlayer thickness of the insulating material 25 (i.e., the interlayer thickness of the laminate 10).

[0039] Furthermore, because the thickness of the insulator 22 below the second circuit pattern 20b, i.e., the interlayer distance α, is controlled by the depth Da of the second circuit pattern trench 62, a thin interlayer distance α of 1 μm or more and 5 μm or less can be achieved without being limited by printing performance, compared to a configuration in which an insulator layer is formed on a conductor layer by screen printing, as in the above-mentioned Patent Document 2. This makes it possible to increase the proportion of the thickness of the laminate 10 in the interlayer direction Z that is occupied by the first circuit pattern 20a and the second circuit pattern 20b, which are conductors, and to obtain a coil component 1 with higher performance.

[0040] Next, the exposure and development process in step Sa3 will be described in detail. FIG. 4 is a diagram showing the processing steps of the exposure and development process. In the exposure and development process of step Sa3, which is the third step, after forming the trench 62 for the second circuit pattern by exposing and developing the surface of the insulating material 25, a via trench 63 is formed at least at the bottom of a part of the trench 62 for the second circuit pattern by performing additional exposure and development on the insulating material 25 at the bottom.

[0041] Specifically, first, with the photomasks 72, 72 disposed at a position separated upward by a predetermined distance in the interlayer direction Z from the surface of the uncured insulating material 25 formed by printing in step Sa2 described above, the first exposure is performed (step Sb1), and then development is carried out (step Sb2). The photosensitive insulating material 25 of the present embodiment is a negative-type material. In this first exposure and development, trenches 62 for the second circuit pattern with a depth Da (<Db) are formed directly below each of the photomasks 72, 72.

[0042] Next, while disposing the photomask 72 at a position separated upward by a predetermined distance in the interlayer direction Z from the trench 62 for the second circuit pattern where the via trench 63 is to be formed, the second exposure is performed without disposing the photomask 72 on the other trenches 62 for the second circuit pattern (step Sb3), and then development is carried out (step Sb4). By this second (i.e., additional) exposure and development, a via trench 63 is formed at the bottom of the trench 62 for the second circuit pattern where the via 24 is to be formed. On the other hand, in the second exposure in step Sb3, the bottom of the part of the trench 62 for the second circuit pattern that is not the formation target of the via 24 (for example, the bottom of the trench 62 for the second circuit pattern on the left side in the drawing) is cured, so that the thickness of the insulating material 25 between the bottom of the trench 62 for the second circuit pattern and the first circuit pattern 20a is formed to a thickness corresponding to the interlayer distance α.

[0043] This exposure and development process forms trenches 62 for the second circuit pattern and trenches 63 for vias, and by performing a process of filling both the trenches 62 for the second circuit pattern and the trenches 63 for vias with conductive paste (Figure 3: step Sa4), the second circuit pattern 20b and the vias 24 can be formed simultaneously. Furthermore, by forming the trench 62 for the second circuit pattern, a layer of insulator 22 is formed between the first circuit pattern 20a and the second circuit pattern 20b, which eliminates the need for a separate process to form an insulator layer between the first circuit pattern 20a and the second circuit pattern 20b, thereby simplifying the processing steps.

[0044] In this embodiment, the insulating material 25 contains a filler material having a refractive index higher than that of the main material, and when the insulating material 25 is exposed and developed to form the trench 62 for the second circuit pattern and the trench 63 for the via, the above-mentioned curved portions 62A, 63A are formed at the bottom of each.

[0045] More specifically, as shown in Fig. 5, glass paste 18 used as insulating material 25 contains filler material 19, and aluminum oxide is used for filler material 19 to ensure the strength of the element. Since aluminum oxide has a higher refractive index than insulating material 25 (more precisely, insulating resin, which is the main material of insulating material 25), when photosensitive insulating material 25 is exposed to light to form second circuit pattern trenches 62 and via trenches 63, scattering, diffraction, and reflection of light H used for exposure occur within insulating material 25, as shown in Fig. 5. By appropriately adjusting the scattering, diffraction, and reflection of light H by adjusting the aluminum oxide content, the following processes can be realized.

[0046] Specifically, as shown in FIG. 6 , during exposure by irradiating the glass paste 18 with collimated exposure light H, the content of aluminum oxide in the filler material 19 is adjusted so that the deeper the glass paste 18 is from the surface, the more the exposure light H is scattered in the X direction and penetrates directly below the photomask M. In this case, in a cross-sectional view in the interlayer direction, the shape of the photo-cured cured area 80 becomes approximately tapered toward the center Mo of the photomask M as the depth increases from the surface of the glass paste 18, and the uncured area 82 directly below the photomask M becomes approximately V-shaped. The uncured area 82 is then removed by development, forming an approximately V-shaped trench 86. During development, the development time is adjusted so that the deep portion of the uncured area 82 (the apex of the V-shape) does not dissolve. As a result, the surface of the trench 86 becomes smoothly curved, as indicated by the dotted line L, and the trench 86 is formed with a curved portion 87 at its bottom. Such trench 86 corresponds to the second circuit pattern trench 62 and the via trench 63.

[0047] The above process is not limited to the method of adjusting the aluminum oxide content of the filler material 19. For example, by making the size of the filler material several times (for example, two or three times) the wavelength of the exposure light H, scattering, diffraction, and reflection can be significantly generated, making it easier to form trenches 86 including curved portions 87. The size of the filler material in this embodiment is 1 μm or less. In addition to aluminum oxide (Al2O3), silicon dioxide (SiO2) and silicon nitride (SiN) can also be used as the filler material that causes scattering.

[0048] In addition to utilizing the optical effect of the filler material 19, it is possible to form a trench 62 for a second circuit pattern and a trench 63 for a via having curved portions 62A, 63A by controlling the development time and the focal position of the light H used for exposure.

[0049] 4, development time control is control in which development is performed by shortening the development time in steps Sb2 and Sb4 below breakpoint BP. Breakpoint BP is the development time at which, when the range from the surface of the insulating material to the underlying first circuit pattern 20a becomes uncured area 82, almost all of uncured area 82 melts to form trenches 86 that penetrate to the underlying first circuit pattern 20a. Note that, because the thickness of the insulating material up to the underlying first circuit pattern 20a differs between steps Sb2 and Sb4, the breakpoint BP also differs.

[0050] 4 (i.e., step Sa3, which is the third step), the second circuit pattern trench 62 is developed for a shorter development time than the breakpoint BP, which is the development time required for the insulating material 25 at the formation location to penetrate into the first circuit pattern 20a. Also, in step Sb4, the via trench 63 is developed for a shorter development time than the breakpoint BP, which is the development time required for substantially all of the uncured area 82 of the insulating material 25 at the formation location to melt.

[0051] 7, development time control will be described below using the development of the two second circuit pattern trenches 62 in step Sb2 as an example. As shown in the figure, when the development time is equal to or greater than the breakpoint BP, the two second circuit pattern trenches 62 become through-holes that penetrate to the underlying first circuit pattern 20a. However, when the development time is shorter than the breakpoint BP, the two second circuit pattern trenches 62 do not become through-holes, and uncured insulating material 25 remains between the two second circuit pattern trenches 62 and the underlying first circuit pattern 20a.

[0052] This uncured insulating material 25 is photocured by the second exposure in step Sb3, and becomes part of the insulator 22 below the second circuit pattern 20b. Since there is a correlation between the development time and the depth Da, such that the shorter the development time, the shallower the depth Da of the trench 62 for the second circuit pattern, the depth Da of the trench 62 for the second circuit pattern can be controlled by adjusting the development time, and the thickness of the insulator 22 below the second circuit pattern 20b can be made the desired thickness (desired interlayer distance α).

[0053] Furthermore, if development is stopped at a development time when the trench 62 for the second circuit pattern reaches a depth Da that does not penetrate into the underlying first circuit pattern 20a, the shape of the bottom of the trench 62 for the second circuit pattern will be curved, thereby forming a curved portion 62A at the bottom. If the development time is shorter than the breakpoint BP, the curvature of the curved portion 62A increases as the development time approaches the breakpoint BP. However, if the development time is set to be sufficiently longer than the breakpoint BP, all of the uncured portions of the insulating material 25 are removed, and the curvature depends on the cured shape (i.e., the degree of penetration of the exposure light) and is unrelated to the development time.

[0054] The focal position control is a control for adjusting the focal position P of the light H used for exposure in each of steps Sb1 and Sb3 in the exposure and development process of FIG. Specifically, in the focus position control, in steps Sb1 and Sb3 of the exposure and development process (step Sa3, which is the third step) shown in Figure 4, the light used to expose the insulating material 25 is irradiated so as to focus on the surface of the insulating material 25 or inside the insulating material 25, closer to the surface.

[0055] As shown in Fig. 8, when light H that has passed through a photomask M is passed through a condenser lens and irradiated onto the surface of the insulating material 25, if the focal position P of the condenser lens is located below the surface of the insulating material 25 in the interlayer direction Z (i.e., inside the insulating material 25), the illuminance inside the insulating material 25 is higher than when parallel light H is irradiated. Therefore, the cured area 80 shown in Fig. 6 expands to a region closer to the center Mo of the photomask M, and as a result, a trench 86 whose width in the X direction is narrowed overall is formed, as shown in Fig. 8. In this case, it can be said that not only the bottom of the trench 86 but the entire trench 86 has a curved portion 87 (a shape that narrows downward in the interlayer direction Z).

[0056] When the focal position P of the condenser lens is located near the surface of the insulating material, the influence of scattering of light H near the surface is small, and therefore the side surface 86S near the opening of trench 86 becomes approximately vertical (approximately parallel to the interlayer direction Z). Furthermore, the influence of scattering of light H increases as the depth from the surface increases, and as described above with reference to FIG. 6, a curved portion 87 is formed at the bottom of trench 86.

[0057] In this way, by performing exposure with the focal position P of the condenser lens positioned near the surface of the insulating material and below the surface, trenches 86 having curved portions 87 can be formed.

[0058] However, when the focal position P of the condenser lens is located above the surface of the insulating material 25, the illuminance of the light H weakens the deeper it goes from the surface, and the effects of scattering and the like become greater, making it more difficult for the insulating material 25 to harden at locations deeper from the surface than when irradiated with parallel light H. As a result, as shown in Figure 8, not only does the trench 86 have an inverse tapered shape, but the width of the opening is also narrowed, making it difficult to fill with conductive paste.

[0059] The trench 86 having the curved portion 87 may be formed by using any combination of two or more of the filler material 19, development time control, and focal position control.

[0060] [Second embodiment] Fig. 9 is a schematic diagram of the internal structure of the coil device 100 according to this embodiment. In this figure, the same reference numerals are used to designate the same members as those described in Fig. 1, and the description thereof will be omitted. As shown in the figure, in a cross-sectional view in the interlayer direction, a laminate 110 included in a coil device 100 of this embodiment has four first circuit patterns 30a, 30b, 30c, and 30d having a configuration similar to the first circuit pattern 20a shown in the first embodiment and four second circuit patterns 32a, 32b, 32c, and 32d having a configuration similar to the second circuit pattern 20b alternately stacked on a support plate 3. Hereinafter, the first circuit patterns 30a, 30b, 30c, and 30d will be collectively referred to as first circuit patterns 30, and the second circuit patterns 32a, 32b, 32c, and 32d will be collectively referred to as second circuit patterns 32.

[0061] When viewed in a cross-sectional view in the interlayer direction, the laminate 110 has the lower end 32A of the second circuit pattern 32a in the interlayer direction Z positioned lower in the interlayer direction Z than the upper end 32A of the first circuit pattern 30a below it in the interlayer direction Z. The first circuit pattern 30c and the second circuit pattern 32c are configured in the same manner as above.

[0062] As a result, in the laminate 110 of the coil device 100, the proportion of the thickness of the laminate 110 in the interlayer direction Z that is occupied by the first circuit pattern 30 and the second circuit pattern 32, which are conductors, can be further increased compared to the laminate 10 or the laminate 11 (FIG. 12) described below in which multiple second circuit patterns 20b are configured in multiple layers.

[0063] In the laminate 110, when viewed in a cross-sectional view in the interlayer direction, a portion of each first circuit pattern 30 and a portion of the adjacent second circuit pattern 32 are formed so as to be directly joined without a via 24, thereby forming a coil body.

[0064] FIG. 10 is a diagram showing the wiring topology of the coil body in the coil device 100. Note that the "wiring topology" refers to a schematic representation of the connection relationship between each of the first circuit patterns 30 and each of the second circuit patterns 32. In the figure, the parentheses attached to the reference numerals of the first circuit patterns 30 and the second circuit patterns 32 indicate the layer number (see FIG. 9) on which the first circuit pattern 30 or the second circuit pattern 32 is formed. FIG. 10 shows the wiring topology formed by the first circuit patterns 30 and the second circuit patterns 32 on the first to fourth layers. The wiring topology formed by the first circuit patterns 30 and the second circuit patterns 32 on the fifth to eighth layers has the same configuration as that shown in FIG. 10.

[0065] As shown in the figure, each of the first circuit pattern 30 and the second circuit pattern 32 corresponds to half a turn of the coil body. Each of the first circuit pattern 30 and the second circuit pattern 32 has a substantially C-shape in plan view when viewed from the interlayer direction Z, and an end point 30T of the first circuit pattern 30 and an end point 32T of the second circuit pattern 32 in plan view are directly joined without vias 24, thereby achieving electrical conduction. This connects the first circuit pattern 30 and the second circuit pattern 32 to form a spiral coil body.

[0066] Next, a method for manufacturing the coil device 100 will be described. FIG. 11 is a diagram showing an example of a manufacturing process for the coil device 100. First, by the processes of steps Sa1 and Sa2 shown in FIG. 4, the first circuit pattern 30a is embedded in the uncured insulating material 25 made of glass paste.

[0067] Next, the surface of the uncured insulating material 25 is exposed and developed to form two trenches 62 for the second circuit pattern (Step Sc1). In this process, of the two trenches 62 for the second circuit pattern, the one that is not connected to the underlying first circuit pattern 30a is formed at a position shifted in the X direction relative to the first circuit pattern 30a (i.e., a position where the first circuit pattern 30a does not exist on an extension line of the interlayer direction Z), and the one that is connected to the first circuit pattern 30a is formed directly above the first circuit pattern 30a.

[0068] The second circuit pattern trenches 62 are formed by exposure and development so that their depth Dd is deeper than the distance De from the surface of the insulating material 25 to the first circuit pattern 30a. As a result, the second circuit pattern trenches 62 formed directly above the first circuit pattern 30a penetrate through to the first circuit pattern 30a. On the other hand, the second circuit pattern trenches 62 formed at positions offset in the X direction from the first circuit pattern 30a are formed to a depth such that the ends 32A enter the height range R of the first circuit pattern 20a. Note that, like the first embodiment, the second circuit pattern trenches 62 also have a curved portion 62A at their bottoms.

[0069] Next, each of the two second circuit pattern trenches 62 is filled with a conductive paste by printing, and the conductive paste is dried (Step Sc2). This forms the second circuit pattern 32a. Next, the third layer of the first circuit pattern 30b is printed using a conductive paste, and the conductive paste is dried (Step Sc3). Then, an insulating material 25, which is a photosensitive glass paste, is printed so as to cover the first circuit pattern 30b exposed on the surface, and then the insulating material 25 is dried (Step Sc4).

[0070] By performing steps Sc1 to Sc4, the first circuit pattern 30a and the second circuit pattern 32a are formed so that, in an interlayer cross-sectional view, the lower end 32A of the second circuit pattern 32a in the interlayer direction Z is positioned lower in the interlayer direction Z than the upper end 32A of the underlying first circuit pattern 30a in the interlayer direction Z. Then, by repeating steps Sc1 to Sc4, other first circuit patterns 30 and second circuit patterns 32 are formed, and a laminate 110 including a spiral coil body with a desired number of turns is manufactured.

[0071] [Other embodiments] In the coil device 1 of the first embodiment, the laminate 10 is configured by stacking one first circuit pattern 20a and one second circuit pattern 20b in two layers, but the configuration of the laminate is not limited to this. For example, the laminate may be configured by stacking one first circuit pattern 20a and multiple (seven in the example of FIG. 12) second circuit patterns 20b in multiple layers, as in the laminate 11 shown in FIG. 12. In this case, the first circuit pattern 20a and the multiple second circuit patterns 20b are electrically connected in series to form a spiral coil body.

[0072] The plurality of second circuit patterns 20b as described above can be manufactured by repeating the processes from step Sa3 to step Sa5, which is not shown, after step Sa4 shown in FIG. 3, in which an insulating material 25, which is a photosensitive glass paste, is further printed and dried so as to cover the second circuit patterns 20b exposed on the upper surface of the insulator 22.

[0073] In the laminate 110 of the coil device 100 of the second embodiment, in the first circuit pattern 30a and the second circuit pattern 32a, and in the first circuit pattern 30c and the second circuit pattern 32c, the lower end of the second circuit pattern 32 in the interlayer direction Z is positioned lower in the interlayer direction Z than the upper end of the underlying first circuit pattern 30 in the interlayer direction Z. However, this is just one example, and the first circuit pattern 30b and the second circuit pattern 32b, and / or the first circuit pattern 30d and the second circuit pattern 32d may also be configured in a similar manner to the above.

[0074] Furthermore, in the coil components 1 and 100 according to the above-described embodiments, the insulating material 25 constituting the insulator 22 may be a magnetic material such as a sintered ferrite body or a resin containing ferrite powder. Such coil components 1 and 100 are suitable for use as power inductors mounted in power supply circuits and the like, or as noise filters that remove noise from AC signals.

[0075] The present invention can be applied not only to the coil components 1 and 100 but also to any other laminated electronic components. The number and positions of the first circuit pattern 20a, the second circuit pattern 20b, and / or the vias 24 shown in the drawings will vary depending on the electronic component to which the present invention is applied.

[0076] It should be noted that the above-described embodiments are merely examples of aspects of the present invention, and any modifications and applications are possible without departing from the spirit of the present invention. Furthermore, unless otherwise specified, the horizontal, vertical, and other directions, various numerical values, shapes, and materials in the above-described embodiments include a range (so-called equivalent range) that produces the same effect as those directions, numerical values, shapes, and materials.

[0077] [Configuration supported by the above embodiments, etc.] The above-described embodiment, modifications, and application examples support the following configurations.

[0078] (Configuration 1) An electronic component comprising a first circuit pattern and a second circuit pattern stacked in this order from bottom to top in an interlayer direction, and an insulator arranged between the first circuit pattern and the second circuit pattern, wherein the second circuit pattern has a shape such that the width, which is the dimension perpendicular to the interlayer direction, of the lower end of the second circuit pattern in the interlayer direction narrows as the end is positioned lower in the interlayer direction in a cross-sectional view including the interlayer direction. In the electronic component of configuration 1, the second circuit pattern having a shape that narrows in width perpendicular to the interlayer direction can be formed by forming a trench in the insulator using photolithography for forming the second circuit pattern. Therefore, in the electronic component of configuration 1, the thickness of the insulator between the second circuit pattern and the first circuit pattern can be controlled to be thin, thereby increasing the proportion of the thickness in the interlayer direction that the first and second circuit patterns, which are conductors, occupy.

[0079] (Configuration 2) The electronic component according to configuration 1, wherein the second circuit pattern has a curved lower end in the interlayer direction. According to the electronic component of configuration 2, the insulator is inserted around the lower end of the second circuit pattern, thereby improving the adhesion between the second circuit pattern and the insulator.

[0080] (Configuration 3) The electronic component according to configuration 1, wherein the second circuit pattern has an upper end in the interlayer direction that is flat. According to the electronic component of configuration 3, the cross-sectional area of ​​the second circuit pattern can be increased, thereby reducing the DC electrical resistance of the second circuit pattern.

[0081] (Configuration 4) The electronic component according to any one of configurations 1 to 3, wherein the first circuit pattern has a lower end in the interlayer direction that is flat. According to the electronic component of configuration 4, the cross-sectional area of ​​the first circuit pattern can be increased, thereby reducing the DC electrical resistance of the first circuit pattern.

[0082] (Configuration 5) An electronic component according to any one of configurations 1 to 4, further comprising a via that electrically connects the first circuit pattern and the second circuit pattern, wherein the width of the via is narrower as the lower end in the interlayer direction is positioned lower in the interlayer direction in a cross-sectional view of a cross section including the interlayer direction. According to the electronic component of configuration 5, the insulator fills the lower end of the via, thereby improving the adhesion between the via and the insulator.

[0083] (Configuration 6) An electronic component according to any one of configurations 1 to 5, wherein, in a cross-sectional view of a cross section including the interlayer direction, a lower end portion of the second circuit pattern in the interlayer direction is located lower in the interlayer direction than an upper end portion of the first circuit pattern in the interlayer direction. According to the electronic component of configuration 6, the proportion of the thickness in the interlayer direction that is occupied by the first circuit pattern and the second circuit pattern, which are conductors, can be further increased.

[0084] (Configuration 7) The electronic component according to any one of configurations 1 to 6, wherein the first circuit pattern and the second circuit pattern are connected to form a spiral coil body. According to the electronic component of configuration 7, the proportion of the interlayer thickness occupied by the first circuit pattern and the second circuit pattern, which are conductors, can be increased, thereby forming a coil component having good electrical characteristics, such as low DC resistance and high inductance value.

[0085] (Structure 8) A method for manufacturing an electronic component, comprising: a first step of forming a first circuit pattern on a plane; a second step of forming a photosensitive insulating material so as to cover the first circuit pattern; a third step of forming a trench for a second circuit pattern by exposing and developing the surface of the insulating material; and a fourth step of filling the trench for the second circuit pattern with a conductive material to form a second circuit pattern, wherein in the third step, the trench for the second circuit pattern is formed having a bottom whose width, which is the dimension perpendicular to the interlayer direction, narrows as it becomes deeper along the interlayer direction, which is the direction in which the first circuit pattern and the second circuit pattern are stacked. According to the manufacturing method of configuration 8, the depth of the trench for the second circuit pattern formed in the insulating material can be precisely controlled using photolithography, so that the thickness of the insulating material between the second circuit pattern and the first circuit pattern can be controlled to be thin, thereby increasing the proportion of the thickness in the interlayer direction that is occupied by the first circuit pattern and the second circuit pattern, which are conductors.

[0086] (Structure 9) A method for manufacturing an electronic component according to Structure 8, wherein in the third step, after forming the trench for the second circuit pattern, a trench for a via is formed at the bottom of at least a portion of the trench for the second circuit pattern by additional exposure and development of the insulating material at the bottom. According to the manufacturing method of configuration 9, the trench for the via is formed by additional exposure and development following the formation of the trench for the second circuit pattern, thereby simplifying the processing steps compared to when the second circuit pattern and the via are formed in separate steps.

[0087] (Configuration 10) The method for producing an electronic component according to Configuration 8 or 9, wherein the insulating material contains a filler material having a refractive index higher than that of the main material. According to the manufacturing method of configuration 10, when the trench for the second circuit pattern and the trench for the via are formed by exposure and development, curved portions can be formed at the bottom of each trench.

[0088] (Configuration 11) The method for manufacturing an electronic component according to any one of Configurations 8 to 10, wherein in the third step, the light used for the exposure is irradiated so as to be focused on the surface of the insulating material or inside the insulating material rather than on the surface. According to the manufacturing method of configuration 11, a trench for a second circuit pattern or a trench for a via having a curved portion at the bottom can be formed by controlling the focus of exposure light.

[0089] (Structure 12) The method for manufacturing an electronic component according to any one of Structures 8 to 11, wherein in the third step, development is performed for a shorter development time than the development time required for the trench for the second circuit pattern to penetrate through to the first circuit pattern. According to the manufacturing method of configuration 12, a trench for a second circuit pattern or a trench for a via having a curved portion at the bottom can be formed by controlling the development time after exposure. [Explanation of symbols]

[0090] 1, 100... Coil component (electronic component), 10, 11, 110... Laminate, 18... Glass paste (insulating material), 19... Filler material, 20a, 30, 30a, 30b, 30c, 30d... First circuit pattern, 20b, 32, 32a, 32b, 32c, 32d... Second circuit pattern, 20A, 32A... End of second circuit pattern, 22... Insulator, 24... Via, 24A... End of via, 25... Insulating material, 52, 53, 62A, 63A, 87... Curved portion, 62... Trench for second circuit pattern, 63... Trench for via, 80... Curved area, 82... Uncured area, 86... Trench, R... Height range, Wa, Wb... Width, Z... Interlayer direction, α... Interlayer distance.

Claims

1. a first circuit pattern and a second circuit pattern stacked in this order from bottom to top in the interlayer direction; an insulator disposed between the first circuit pattern and the second circuit pattern; Equipped with The second circuit pattern is The lower end portion in the interlayer direction is In a cross-sectional view of a cross section including the interlayer direction, the width, which is a dimension perpendicular to the interlayer direction, becomes narrower as the position becomes lower in the interlayer direction, In a cross-sectional view of a cross section including the interlayer direction, a lower end of the second circuit pattern in the interlayer direction, the first circuit pattern is located below an upper end of the first circuit pattern in the interlayer direction, the first circuit pattern and the second circuit pattern are directly joined and electrically connected without a via; Electronic components.

2. the second circuit pattern has a curved lower end in the interlayer direction; The electronic component according to claim 1 .

3. an upper end portion of the second circuit pattern in the interlayer direction being flat; The electronic component according to claim 1 .

4. a lower end portion of the first circuit pattern in the interlayer direction being flat; The electronic component according to claim 1 .

5. The first circuit pattern and the second circuit pattern are connected to form a spiral coil body. The electronic component according to any one of claims 1 to 4.

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