Circuit module

Abstract

Provided is a circuit module (1) which comprises a substrate (10) that has one main surface (10a) and another main surface (10b) and a connection terminal (30) that is disposed on the one main surface (10a)-side of the substrate (10), said circuit module (1) being characterized in that: a first electrode (11) is provided on the one main surface (10a) of the substrate (10); on the one main surface (10a)-side of the substrate (10), an edge face of the connection terminal (30) partially joins to a portion of a surface of the first electrode (11); when the first electrode is seen from the thickness direction, a first portion (11a) is defined as a portion of the surface of the first electrode (11) which joins to the connection terminal (30) and a second portion (11b) is defined as a portion of the first electrode (11) which surrounds the outer periphery of the first portion (11a) and which does not join to the connection terminal (30); and a ceramic protective film (70) made of a ceramic material is provided between the surface of the second portion (11b) and a portion of the edge face of the connection terminal (30) that does not join to the first portion (11a).

Description

Circuit Module

[0001] The present invention relates to a circuit module.

[0002] 2. Description of the Related Art Components mounted in electronic devices include circuit modules in which electronic components are mounted on a substrate such as an LTCC substrate and sealed with resin.

[0003] When mounting a circuit module having electronic components mounted on both sides of the substrate on another substrate (mounting substrate) such as a motherboard, electrodes (external connection terminals or connection terminals) that penetrate the resin layer in the thickness direction are required to connect the circuit module substrate to the mounting substrate.

[0004] For example, Patent Document 1 discloses a circuit module including a substrate having a first electrode and a second electrode provided on one main surface thereof, a first electronic component connected to the first electrode, and a first resin layer provided on one main surface of the substrate, in which the second electrode is composed of a second electrode base connected to the substrate, a metal pillar made of sintered metal powder and having one end directly connected to the second electrode base and the other end located inside the outer surface of the first resin layer, a plating layer covering the second electrode base and the side surfaces of the metal pillar, and a covering portion having one main surface connected to the other end of the metal pillar and the plating layer and the other main surface located outside the outer surface of the first resin layer.

[0005] Patent document 1 discloses that by providing a plating film that is compatible with the resin layer on the side of the metal pillar that constitutes the second electrode that serves as the connection terminal, it is possible to improve adhesion between the metal pillar and the resin layer and suppress peeling.

[0006] Patent No. 6791352

[0007] In recent years, there has been an increasing demand for miniaturization and high reliability of electronic components. However, due to miniaturization, cracks are more likely to occur at the interface between the metal posts and the substrate due to thermal cycles and impacts when the housing is dropped.

[0008] Patent Document 1 discloses that a plating film is provided at the interface between the metal pillar, which is the external connection terminal, and the resin layer to improve adhesion between the metal pillar and the resin layer, but does not disclose anything about suppressing cracks that occur between the substrate and metal pillar that constitute the circuit module.

[0009] Generally, in heterogeneous joints such as those between a ceramic substrate and a metal pillar, it is possible to suppress thermal stress by reducing the size of the metal pillar, which has a large thermal expansion coefficient. However, the area, shape, position, etc. of the connection terminal (metal pillar) on the mounting surface are determined by the specifications of the mounting destination (customer).

[0010] The mounting specifications include the position and shape of the connection terminals for the circuit module on the mounting board on which the circuit module is mounted. When mounting the circuit module on the mounting board, the position and shape of the metal posts that connect to the mounting board must match the position and shape of the connection terminals on the mounting board. Therefore, once the area, shape, position, etc. of the connection terminals (metal posts) have been determined as the mounting specifications, they cannot be changed for the circuit module's convenience in order to improve thermal cycle characteristics or connection reliability.

[0011] For these reasons, there has been a demand for improved thermal cycle characteristics and connection reliability without being affected by the specifications of the mounting destination.

[0012] The present invention has been made to solve the above problems, and aims to provide a circuit module that can improve thermal cycle characteristics and connection reliability without being affected by the specifications of the mounting destination.

[0013] The circuit module of the present invention is a circuit module comprising a substrate having one main surface and another main surface, and a connection terminal arranged on the one main surface side of the substrate, wherein a first electrode is provided on the one main surface of the substrate, and on the one main surface side of the substrate, a portion of the end face of the connection terminal is joined to a portion of the surface of the first electrode, when the first electrode is viewed from the thickness direction, the portion of the surface of the first electrode that is joined to the connection terminal is defined as a first portion, and a portion surrounding the periphery of the first portion and not joined to the connection terminal of the first electrode is defined as a second portion, and a ceramic protective film made of a ceramic material is provided between the surface of the second portion and the portion of the end face of the connection terminal that is not joined to the first portion.

[0014] According to the present invention, it is possible to provide a circuit module that can improve thermal cycle characteristics and connection reliability without being affected by the specifications of the mounting destination.

[0015] FIG. 1 is a top view schematically illustrating an example of a circuit module according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1. FIG. 3 is a diagram illustrating the correspondence between a partial enlargement of FIG. 2 and a schematic diagram of the joint surface between a connection terminal and a first electrode in the enlarged portion, as viewed from the metal post side. FIG. 4 is an enlarged cross-sectional view of the joint portion between a connection terminal and a first electrode in another example of a circuit module of the present invention. FIG. 5 is a top view schematically illustrating yet another example of a first electrode. FIG. 6 is an enlarged view schematically illustrating the joint portion between a connection terminal and a first electrode in another example of a circuit module of the present invention. FIG. 7 is a cross-sectional view schematically illustrating an example of a constraining layer sheet used in manufacturing a circuit module. FIG. 8 is a cross-sectional view schematically illustrating a step of printing a conductive paste on the surface of the constraining layer sheet shown in FIG. 7. FIG. 9 is a cross-sectional view schematically illustrating a step of forming through holes in the surface of the constraining layer sheet shown in FIG. 7. FIG. 10 is a cross-sectional view schematically illustrating a step of filling the through holes in the constraining layer sheet shown in FIG. 9 with a conductive paste. FIG. 11 is a cross-sectional view schematically showing an example of a ceramic green sheet used in manufacturing a circuit module. FIG. 12 is a cross-sectional view schematically showing a step of printing a conductive paste on the surface of the ceramic green sheet shown in FIG. 11. FIG. 13 is a cross-sectional view schematically showing a step of forming through holes in the surface of the ceramic green sheet shown in FIG. 11. FIG. 14 is a cross-sectional view schematically showing a step of filling the through holes of the ceramic green sheet shown in FIG. 13 with a conductive paste. FIG. 15 is a cross-sectional view schematically showing a step of printing a conductive paste on the surface of the ceramic green sheet shown in FIG. 14. FIG. 16 is a cross-sectional view schematically showing a step of printing a conductive paste and a ceramic protective film paste on the surface of the ceramic green sheet shown in FIG. 14. FIG. 17 is a diagram schematically showing an example of a step of stacking prepared laminate sheets. FIG. 18 is a diagram schematically showing an example of a step of pressure-bonding a laminate. FIG. 19 is a diagram schematically showing an example of a step of firing the pressure-bonded body. FIG. 20 is a diagram schematically showing an example of a step of removing a constraining layer. Fig. 21 is a diagram schematically illustrating an example of a process for forming a plating film, and Fig. 22 is a diagram schematically illustrating an example of a process for mounting electronic components on one main surface of a substrate.Fig. 23 is a cross-sectional view schematically showing an example of a step of encapsulating an electronic component. Fig. 24 is a cross-sectional view schematically showing an example of a step of grinding the surface of the encapsulating resin. Fig. 25 is a cross-sectional view schematically showing a step of forming a plating film on the surface of a connection terminal. Fig. 26 is a cross-sectional view schematically showing a step of mounting an electronic board on the other main surface of the substrate. Fig. 27 is a cross-sectional view schematically showing an example of a step of encapsulating an electronic component. Fig. 28 is a cross-sectional view schematically showing an example of a step of grinding the surface of the encapsulating resin.

[0016] The circuit module of the present invention will be described below. However, the present invention is not limited to the following configuration, and can be modified as appropriate within the scope of the present invention. Note that a combination of two or more of the individual desirable configurations of the present invention described below also constitutes the present invention.

[0017] In this specification, terms indicating the relationship between elements (e.g., "parallel," "orthogonal," "opposite," etc.) are not expressions that only express a strict meaning, but also expressions that include a substantially equal range, for example, a difference of a few percent.

[0018] The drawings shown below are schematic diagrams, and the dimensions, aspect ratios, and other scales may differ from those of the actual product.

[0019] [Circuit Module] A circuit module of the present invention includes a substrate having one main surface and another main surface, and a connection terminal arranged on the one main surface side of the substrate, wherein a first electrode is provided on the one main surface of the substrate, and on the one main surface side of the substrate, part of an end face of the connection terminal is joined to part of a surface of the first electrode, when the first electrode is viewed in the thickness direction, a part of the surface of the first electrode that is joined to the connection terminal is defined as a first part, and a part of the first electrode that surrounds the periphery of the first part and is not joined to the connection terminal is defined as a second part, and a ceramic protective film made of a ceramic material is provided between the surface of the second part and the part of the end face of the connection terminal that is not joined to the first part.

[0020] Fig. 1 is a top view schematically showing an example of a circuit module according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1. As shown in Figs. 1 and 2, the circuit module 1 includes a substrate 10, a first resin layer 20, and connection terminals 30, with electronic components 40 and connection terminals 30 exposed on the main surface of the first resin layer 20 opposite the substrate 10.

[0021] As shown in Figure 2, the substrate 10 has one main surface 10a and the other main surface 10b, and has a first electrode 11 and a second electrode 14 provided on the one main surface 10a, via conductors 15 and wiring 17 provided inside, and a third electrode 19 provided on the other main surface 10b.

[0022] The first resin layer 20 is disposed on one main surface 10a of the substrate 10, and the one main surface 10a of the substrate 10 is covered with a sealing resin 26. The first resin layer 20 has a first main surface 20a on the substrate 10 side and a second main surface 20b on the opposite side to the substrate 10.

[0023] An electronic component 40 is mounted on one main surface 10a of the substrate 10. The electronic component 40 is connected to the second electrode 14 via solder 50. It can be said that the electronic component 40 is disposed in the first resin layer 20. A plating film 23 may be formed on the surface of the second electrode 14, as shown in Fig. 2. Furthermore, a plating film 23 may also be formed on the surface of the third electrode 19, as shown in Fig. 2.

[0024] The connection terminal 30 is disposed on one main surface 10a of the substrate 10. One end face of the connection terminal 30 is partly joined to a part of the surface of the first electrode 11, and the other end face is exposed on the second main surface 20b of the first resin layer 20. The connection terminal 30 extends in the thickness direction of the substrate 10 (the vertical direction on the paper), and its height (indicated by the double-headed arrow h in FIG. 3 ) is 1 / 2. ３０ The height indicated by ( ) is equal to the thickness of the first resin layer 20 .

[0025] Fig. 3 is a diagram showing the correspondence between the partially enlarged view of Fig. 2 and a schematic diagram of the bonding surface between the connection terminal and the first electrode in the enlarged view, as viewed from the connection terminal side. The lower view of Fig. 3 is the partially enlarged view of Fig. 2, and the upper view of Fig. 3 is a schematic diagram of the bonding surface between the connection terminal and the first electrode, as viewed from the connection terminal side, corresponding to the partially enlarged view.

[0026] As shown in the lower drawing of FIG. 3, the direction in which the first electrodes 11 extend (left-right direction on the paper) is perpendicular to the direction in which the connection terminals 30 extend (up-down direction on the paper).

[0027] As shown in Fig. 3, the first electrode 11 is divided into two parts, a first part and a second part. The first part is a part where the surface of the first electrode 11 is joined to the connection terminal 30 (the part indicated by reference symbol 11a and a double-headed arrow 11a in Fig. 3). The second part is a part that surrounds the outer periphery of the first part 11a and where the first electrode 11 is not joined to the connection terminal 30 (the part indicated by reference symbol 11b and a double-headed arrow 11b in Fig. 3).

[0028] In the first portion 11a, the surface of the first electrode 11 is joined to a part of the connection terminal 30. The first portion 11a of the first electrode 11 is also flush with one main surface 10a of the substrate 10. In the second portion 11b, a ceramic protective film 70 made of a ceramic material is provided on the surface of the first electrode 11. It can be said that the second portion 11b of the first electrode 11 is buried under the ceramic protective film 70.

[0029] A portion of the end face of the connection terminal 30 on the first electrode 11 side is not joined to the first electrode 11. Therefore, a ceramic protective film 70 made of a ceramic material is provided between the surface of the second portion 11b of the first electrode 11 and the end face of the connection terminal 30 on the first electrode 11 side.

[0030] When a ceramic protective film 70 is provided between the surface of the second portion 11b of the first electrode 11 and a portion of the end face of the connection terminal 30 on the first electrode 11 side that is not joined to the first portion (hereinafter simply referred to as between the second portion 11b and the connection terminal 30), the outer periphery of the joint (first portion) between the first electrode 11 and the connection terminal 30 is covered with the ceramic protective film 70, thereby increasing the mechanical strength of the first electrode 11. This improves thermal cycle characteristics and connection reliability. Furthermore, since the ceramic protective film 70 is provided between the second portion 11b and the connection terminal 30, mismatch between conductor contraction and ceramic contraction during firing is reduced, resulting in a substrate 10 with low internal stress (residual stress). Reducing the internal stress (residual stress) of the substrate 10 reduces stress at the joint between the connection terminal 30 and the first electrode 11 inside the substrate, which is thought to contribute to improved thermal cycle characteristics and connection reliability.

[0031] Unless otherwise specified, the surface of the first electrode in this specification refers to the surface of the first electrode on the connection terminal side. In other words, the surface of the first electrode on the connection terminal side is the surface that can be seen when viewing the first electrode from the connection terminal side in the thickness direction.

[0032] When the first electrode 11 is viewed from the thickness direction, the shape of the first portion 11a is a diameter R １１ａ The shape of the second portion 11b is a circle having a width W １１ｂ It has a ring shape.

[0033] The diameter R of the first portion 11a of the connection terminal 30 １１ａ is the diameter R of the connection terminal 30 ３０ That is, only a portion of the end of the connection terminal 30 on the substrate 10 side is joined to the first electrode 11. Of the end of the connection terminal 30 on the substrate 10 side, a ceramic protective film 70 is disposed on the portion that is not joined to the first electrode 11 (the portion facing the second portion 11b).

[0034] The ceramic protective film 70 is also provided on the outer periphery of the second portion 11b of the first electrode 11. For example, in the upper drawing of Figure 3, the ceramic protective film 70 is provided so as to cover the outer periphery of the second portion 11b of the first electrode 11.

[0035] (Substrate) The substrate has one main surface and the other main surface.

[0036] The substrate is formed by laminating multiple insulating layers on which conductor patterns that form circuits are arranged, such as electrodes exposed on one or the other main surface of the substrate, and wiring and via conductors arranged inside the substrate.

[0037] A first electrode is provided on one main surface of the substrate, and the first electrode is an electrode joined to the connection terminal.

[0038] A second electrode may be provided on one main surface of the substrate. The second electrode is, for example, an electrode to be connected to an electronic component.

[0039] A third electrode may be provided on the other main surface of the substrate. The third electrode is an electrode to be connected to, for example, an electronic component.

[0040] Examples of electronic components include multilayer capacitors, multilayer inductors, filters, and ICs.

[0041] The ceramic material that constitutes the insulating layer includes a low temperature co-fired ceramic (LTCC) material.

[0042] Low-temperature co-fired ceramic materials are ceramic materials that can be fired at temperatures of 1000°C or less and can be co-fired with Au, Ag, Cu, etc., which have low resistivity. Specific examples of low-temperature co-fired ceramic materials include glass composite low-temperature co-fired ceramic materials obtained by mixing ceramic powders such as alumina, zirconia, magnesia, and forsterite with borosilicate glass; ZnO-MgO-Al ２ O ３ -SiO ２ Glass-ceramic low-temperature fired ceramic material using BaO-Al ２ O ３ -SiO２ Ceramic powder and Al ２ O ３ -CaO-SiO ２ -MgO-B ２ O ３ Examples of suitable ceramic materials include non-glass-based low-temperature fired ceramic materials using ceramic powders.

[0043] The conductive material constituting the conductor pattern may be any material that can be co-fired with the low-temperature co-fired ceramic material, such as Cu, Ag, Au, and alloys thereof.

[0044] (First Electrode) The first electrode is provided on one main surface of the substrate.

[0045] In this specification, the first electrode is defined as having two portions, a first portion and a second portion, when viewed from the thickness direction. The first portion is a portion that is bonded to a part of the end face of the connection terminal. The second portion is a portion that surrounds the outer periphery of the first portion and is not bonded to the connection terminal.

[0046] In the first portion, the surface of the first electrode is joined to the connection terminal, and in the second portion, the surface of the first electrode is not joined to the connection terminal and is provided with a ceramic protective film made of a ceramic material.

[0047] The first and second portions of the first electrode can be determined by the following procedure. First, a portion of the first electrode that is bonded to the connection terminal is identified. When viewed from the thickness direction, the portion of the first electrode that is bonded to the connection terminal is determined as the first portion. Next, a portion of the surface of the first electrode that is not bonded to the connection terminal, surrounding the first portion, is identified. The portion of the first electrode that is not bonded to the connection terminal is determined as the second portion.

[0048] The surface of the first electrode means the surface of the first electrode on the connection terminal side. The surface of the first electrode opposite the connection terminal is the surface that is connected to the via conductor in the substrate.

[0049] The area of ​​the first portion as viewed in the thickness direction is not particularly limited, but is preferably 1900 μm ２ More than 18000μm ２ It is preferable that:

[0050] The thickness of the first electrode in the first portion is preferably 5 μm or more and 20 μm or less.

[0051] The shape of the second portion as viewed in the thickness direction is preferably a ring shape surrounding the outer periphery of the first portion.

[0052] The width of the second portion as viewed in the thickness direction is preferably 30 μm or more and 150 μm or less. For example, if the shape of the second portion as viewed in the thickness direction is annular, the width of the second portion can be calculated by {[(outer diameter of the second portion) - (inner diameter of the second portion)] / 2}.

[0053] The thickness of the first electrode in the second portion may be gradually reduced from the center (the first portion side) toward the outside, i.e., the surface of the first electrode in the second portion may be inclined toward the outside.

[0054] When the first electrode is viewed in the thickness direction, the area of ​​the second portion is preferably larger than the area of ​​the first portion. When the area of ​​the second portion of the first electrode is larger than the area of ​​the first portion, the ceramic protective film can easily suppress thermal expansion of the first portion.

[0055] When viewed in the thickness direction, the area of ​​the first electrode on the side opposite to the connection terminal may be smaller or larger than the area of ​​the connection terminal.

[0056] In FIG. 3, the diameter R of the first electrode 11 on the side opposite to the connection terminal 30 is １１ and the diameter R of the connection terminal 30 ３０ Regarding the relationship between ３０ <R １１ Therefore, it can be said that the area of ​​the first electrode 11 on the opposite side to the connection terminal 30 when viewed in the thickness direction is larger than the area of ​​the connection terminal 30 .

[0057] 4 is an enlarged cross-sectional view of a joint between a connection terminal and a first electrode in another example of the circuit module of the present invention. In FIG. 4, the diameter R of the first electrode 12 on the side opposite to the connection terminal 30 is １２ and the diameter R of the connection terminal 30 ３０ Regarding the relationship between ３０ >R１２ Therefore, when viewed in the thickness direction, the area of ​​the first electrode 12 on the side opposite to the connection terminal 30 is smaller than the area of ​​the connection terminal 30 .

[0058] The first portion 12a, which is the portion of the surface of the first electrode 12 that is joined to the connection terminal 30, is also flush with one main surface 10a of the substrate 10. The second portion 12b, which is the portion of the surface of the first electrode 12 that is not joined to the connection terminal 30, can be said to be buried under the ceramic protective film 70.

[0059] The shape of the first portion as viewed in the thickness direction is not particularly limited, but examples thereof include a circle and a polygon.

[0060] The shape of the first portion as viewed in the thickness direction may be, for example, a shape including a circular portion and a pair of protrusions protruding outward from the circular portion. The arrangement of the pair of protrusions is not particularly limited, but it is preferable that they are arranged at positions facing each other across the center of gravity of the circular portion.

[0061] 5 is a top view schematically illustrating yet another example of a first electrode. The first electrode 13 shown in FIG. 5 has a first portion 13a that is the central portion and a second portion 13b that surrounds the outer periphery of the first portion. The top view of the first portion 13a has a circular shape with a pair of protrusions. Specifically, the shape of the first portion 13a is a circular portion 13a. １ and the circular portion 13a １ A pair of protrusions 13a protruding outward from ２ and 13a ３ The shape has a pair of protrusions 13a ２ and 13a ３ The circular portion 13a １ 5, even if the connection terminal and the first electrode are misaligned in the direction in which the protrusion is disposed, the connection between the connection terminal and the first electrode is more likely to be ensured.

[0062] (Connection Terminals) The connection terminals are arranged on one main surface side of the substrate.

[0063] On one main surface of the substrate, a part of the end face of the connection terminal is joined to a part of the surface of the first electrode.

[0064] The connection terminal extends along the thickness direction of the substrate, and the other end is exposed on the second main surface of the first resin layer.

[0065] The height of the connection terminals can be adjusted appropriately to match the height of the electronic components mounted on one main surface of the substrate, and can be, for example, 30 μm or more and 150 μm or less.

[0066] The shape of the connection terminal may be any shape as long as it is columnar, for example, it may be a circular cylinder or a polygonal cylinder.

[0067] The connection terminal may have a tapered shape.

[0068] Examples of materials that can form the connection terminals include Cu, Ag, Au, and alloys thereof.

[0069] When the connection terminal has a cylindrical shape, the diameter of the connection terminal is preferably 150 μm or more and 250 μm or less, and more preferably 180 μm or more and 250 μm or less.

[0070] (Ceramic Protective Film) Materials constituting the ceramic protective film include low-temperature co-fired ceramic (LTCC) materials.

[0071] The ceramic protective film may be disposed so as to cover the outer periphery of the second portion.

[0072] The low-temperature co-fired ceramic that constitutes the ceramic protective film may be the same as or different from the low-temperature co-fired ceramic that constitutes the substrate.

[0073] The thermal expansion coefficient of the connection terminal is μ １ , the thermal expansion coefficient of the ceramic protective film is μ ２ When μ １ >μ ２ It is preferable that the thermal expansion coefficient μ of the connection terminal joined to the first portion of the first electrode is satisfied. １ The thermal expansion coefficient μ of the ceramic protective film provided between the second portion and the connection terminal is ２If this is small, the thermal expansion of the central connection terminal is not easily transmitted to the outside of the board.

[0074] Thermal expansion coefficient μ of connection terminal １ and the thermal expansion coefficient μ of the ceramic protective film ２ can be measured by thermomechanical analysis.

[0075] Thermal expansion coefficient μ of connection terminal １ is 15 x 10 －６ [K －１ ] or more, 17 x 10 －６ [K －１ The thermal expansion coefficient μ of the ceramic protective film is preferably equal to or less than 10 ... ２ is 3 x 10 －６ [K －１ ] or more, 12 x 10 －６ [K －１ ] or less.

[0076] When the low-temperature co-fired ceramic forming the ceramic protective film and the low-temperature co-fired ceramic forming the substrate have the same material composition, it may be impossible to confirm the presence of the ceramic protective film on the surface of the first electrode in the second portion. An example of this case will be described with reference to FIG.

[0077] FIG. 6 is an enlarged view schematically showing a joint portion between a connection terminal and a first electrode in another example of a circuit module of the present invention.

[0078] 6, similarly to the circuit module shown in Fig. 3, the first electrode can be divided into two portions, a first portion and a second portion. The first portion 11a is a portion that is bonded to a part of the surface of the connection terminal 30. The second portion 11b is a portion that surrounds the outer periphery of the first portion 11a and is not bonded to the connection terminal 30.

[0079] A ceramic protective film 70 made of a ceramic material is provided between the second portion 11b and the connection terminal 30. However, if the ceramic material constituting the ceramic protective film provided between the second portion 11b and the connection terminal 30 and the ceramic material constituting the substrate have the same composition, the ceramic protective film 70 in the substrate cannot be distinguished in a cross section such as that shown in Fig. 6. In Fig. 6, the region where the ceramic protective film is presumed to be formed is indicated by a dashed line and is designated by the reference numeral 70.

[0080] The second portion 11b surrounds the outer periphery of the first portion 11a and is not joined to the connection terminal 30. Since the second portion 11b constitutes the outermost portion of the first electrode 11, once the first portion 11a that is joined to the connection terminal 30 is identified, all of the portions outside of that that are not joined to the connection terminal 30 are determined to be the second portion 11b.

[0081] Therefore, when the first electrode 11 is viewed from the thickness direction, the shape of the first portion 11a is a diameter R １１ａ The shape of the second portion 11b is a circle with a width w １１ｂ It has a ring shape.

[0082] In the second portion 11b, the thickness of the first electrode 11 gradually decreases toward the outside (the direction opposite to the first portion 11a). １ The thickness of the ceramic material disposed between the first portion 11a and the connection terminal 30 is thinner as it approaches the first portion 11a and thicker as it moves away from the first portion 11a.

[0083] In the first portion 11a, the surface of the first electrode 11 on the connection terminal 30 side is parallel to the surface opposite to the connection terminal 30, whereas in the second portion 11b, the surface 11b on the connection terminal 30 side of the first electrode 11 is parallel to the surface 11b １ and the surface 11b opposite to the connection terminal 30 ２ and are not parallel.

[0084] The cross-sectional shape of the second portion 11b of the first electrode 11 in FIG. 6 is a widthwise end portion 11b of the first electrode 11 extending from the outer edge of the first portion 11a of the first electrode 11 on the surface on the connection terminal 30 side to the widthwise end portion 11b of the first electrode 11. ３ The edge extending toward the surface 11b １ ) and a portion of the first electrode 11 on the surface opposite to the connection terminal 30 extending from the outer edge of the first portion 11a of the first electrode 11 to the end 11b in the width direction of the first electrode 11. ３ The edge extending toward the surface 11b ２ It can be said that the shape is surrounded by the edges (the sides corresponding to the edges).

[0085] The outer edge of the second portion 11b of the first electrode 11, i.e., the end 11b in the width direction of the first electrode 11 in the cross-sectional view ３ The position of the first electrode 11 may be on an extension plane L extending from the surface of the first part 11a of the first electrode 11 opposite the connection terminal 30, or may be on the opposite side of the connection terminal 30 (below the paper) based on the extension plane L.

[0086] The end 11b in the width direction of the first electrode 11 shown in FIG. ３ is disposed on the opposite side of the connection terminal 30 (below the paper surface) with respect to the extension plane L. In this case, it can be said that the second portion 11b of the first electrode 11 is slightly bent toward the opposite side of the connection terminal 30. The bending point is the boundary between the first portion 11a and the second portion 11b.

[0087] The shape of the first electrode 11 in FIG. 6 is the same as that of the first electrode 11 shown in FIG. 3 , so in FIG. ３０ <R １１ Therefore, when viewed in the thickness direction, the area of ​​the first electrode 11 on the side opposite to the connection terminal 30 is larger than the area of ​​the connection terminal 30 .

[0088] (First Resin Layer) A first resin layer may be disposed on one main surface of the substrate.

[0089] The first resin layer has a first main surface facing the substrate and a second main surface facing away from the substrate.

[0090] When the first resin layer is disposed, the connection terminals are disposed in the first resin layer.

[0091] The sealing resin constituting the first resin layer may be either a thermosetting resin or a thermoplastic resin. Examples of thermosetting resins include phenolic resin, epoxy resin, polyester resin, silicone resin, and polyimide resin. Examples of thermoplastic resins include thermoplastic liquid crystal polymer (LCP), thermoplastic polyimide resin, polyether ether ketone resin (PEEK), and polyphenylene sulfide resin (PPS).

[0092] The sealing resin constituting the first resin layer may contain additives such as fillers, etc. Examples of fillers include glass, silica, aluminum oxide, aluminum nitride, and boron nitride.

[0093] (Plating Film) A plating film may be provided on the surfaces of the connection terminal, the second electrode, the third electrode, and the like.

[0094] By providing a plating film on the side surfaces of the connection terminals and the surfaces exposed on the second main surface of the first resin layer, it is possible to improve connection stability when the circuit module is mounted on a mounting board, etc. By providing a plating film on the surfaces of the second electrodes and the third electrodes, it is possible to improve connection stability when an electronic component is mounted.

[0095] Examples of materials that can be used to form the plating film include Cu, Ag, Au, Ni, Sn, and Pd.

[0096] A second resin layer may further be disposed on the other main surface of the substrate.

[0097] An electronic component may be disposed in the second resin layer. When an electronic component is disposed in the second resin layer, the electronic component is preferably connected to a third electrode disposed on the other main surface of the substrate via solder. In this case, the electronic component can be said to be mounted on the other main surface of the substrate.

[0098] The types of sealing resin and filler constituting the second resin layer may be the same as or different from those of the first resin layer.

[0099] (Shielding Film) A shielding film may be provided on the surface (top surface) and side surfaces of the second resin layer opposite the substrate, and on the side surfaces of the substrate. The shielding film can be formed by, for example, sputtering. In addition to sputtering, the shielding film can also be formed by existing methods such as coating of a conductive resin, plating, and vapor deposition.

[0100] In this case, it is preferable that a ground electrode is provided so as to be exposed on the side surface of the substrate, and that the ground electrode is connected to the shielding film.

[0101] The shielding film may extend to the side surface of the first resin layer.

[0102] The circuit module may have a plurality of connection terminals.

[0103] [Method for Manufacturing Circuit Module] Next, an example of a method for manufacturing the circuit module of the present invention will be described with reference to the drawings. However, the order of each step described below, the number of layers, and the configuration of each sheet are not limited to the contents of the drawings. Furthermore, each step described below is a method for manufacturing a circuit module in a pre-divided state, but multiple circuit modules may be manufactured in an assembled state and then divided into individual pieces.

[0104] 7 is a cross-sectional view showing a schematic example of a constraining layer sheet used in manufacturing a circuit module. First, as shown in FIG. 7, a constraining layer sheet 130 and a carrier film 90 are laminated together. The constraining layer sheet 130 from which the carrier film 90 has been peeled off is also referred to as a laminated sheet 100A.

[0105] The raw material for the constraining layer sheet, a hard-to-sinter ceramic material, is mixed with an organic binder and a plasticizer in any desired amounts to prepare a slurry, which is then applied to the surface of a carrier film and formed into a sheet, thereby obtaining a laminate of a constraining layer sheet and a carrier film, as shown in Figure 7.

[0106] Examples of the sintering-resistant ceramic material include Al ２ O ３ Examples include powders.

[0107] Fig. 8 is a cross-sectional view schematically showing a step of printing a conductive paste on the surface of the constraining layer sheet shown in Fig. 7. As shown in Fig. 8, a conductive paste 142 is printed on the surface of the constraining layer sheet 130 shown in Fig. 7. This allows a laminate sheet 100B to be obtained in which the conductive paste 142 is printed on the surface of the constraining layer sheet 130.

[0108] The conductive paste can be obtained by dispersing a conductive material, such as copper powder, in an organic binder.

[0109] The conductive paste is printed on the surface of the constraining layer sheet by a known method such as screen printing.

[0110] Fig. 9 is a cross-sectional view schematically showing a process of forming a through hole in the surface of the constraining layer sheet shown in Fig. 7. As shown in Fig. 9, a through hole 180 is formed in the constraining layer sheet 130 shown in Fig. 7. The method of forming the through hole is not particularly limited, and examples include laser irradiation and drilling.

[0111] Fig. 10 is a cross-sectional view schematically showing a step of filling the through holes of the constraining layer sheet shown in Fig. 9 with a conductive paste. Next, as shown in Fig. 10, the through holes 180 of the constraining layer sheet 130 shown in Fig. 9 are filled with a conductive paste. This results in a laminated sheet 100C in which the conductive paste 131 is filled so as to penetrate the constraining layer sheet 130 in the thickness direction. The conductive paste 131 filled in the through holes 180 becomes a connection terminal by sintering.

[0112] The conductive paste is filled into the through holes by a known method such as screen printing.

[0113] 11 is a cross-sectional view showing a schematic example of a ceramic green sheet used in manufacturing a circuit module, in which a carrier film 90 and a ceramic green sheet 110 are laminated together as shown in FIG.

[0114] A low-temperature co-fired ceramic material, an organic binder, and a plasticizer are mixed in any desired amounts to prepare a slurry, which is then applied to the surface of a carrier film and formed into a sheet, thereby obtaining a laminate of a ceramic green sheet and a carrier film, as shown in FIG. 10.

[0115] Fig. 12 is a cross-sectional view schematically showing a step of printing a conductive paste on the surface of the ceramic green sheet shown in Fig. 11. Subsequently, as shown in Fig. 12, a conductive paste 142 is printed by printing on the surface of the ceramic green sheet 110 shown in Fig. 11. This results in a laminate sheet 100D in which the conductive paste 142 is printed on the surface of the ceramic green sheet 110. Note that in Fig. 17 described later, two types of laminate sheets 100D are used, in which the printed conductive paste 142 is printed at different positions.

[0116] Fig. 13 is a cross-sectional view schematically showing a step of forming a through hole in the surface of the ceramic green sheet shown in Fig. 11. As shown in Fig. 13, a through hole 181 is formed in the ceramic green sheet 110 shown in Fig. 11. The method of forming the through hole is the same as the step shown in Fig. 9.

[0117] Fig. 14 is a cross-sectional view schematically showing a step of filling the through holes of the ceramic green sheet shown in Fig. 13 with a conductive paste. Subsequently, as shown in Fig. 14, the through holes 181 are filled with the conductive paste. This results in a laminated sheet 100E in which the conductive paste 140 is filled so as to penetrate the ceramic green sheet 110 in the thickness direction.

[0118] Fig. 15 is a cross-sectional view schematically showing a step of printing a conductive paste on the surface of the ceramic green sheet shown in Fig. 14. Subsequently, as shown in Fig. 15, a conductive paste 142 is printed by printing on the surface of the ceramic green sheet 110 shown in Fig. 14. As a result, the conductive paste 140 is filled so as to penetrate the ceramic green sheet 110 in the thickness direction, and a laminate sheet 100F having the conductive paste 142 printed on the surface is obtained.

[0119] 16 is a cross-sectional view schematically illustrating a process of printing a conductive paste and a ceramic protective film paste on the surface of the ceramic green sheet shown in FIG. 14. Next, as shown in FIG. 16, a conductive paste 142 is printed on the surface of the ceramic green sheet 110 shown in FIG. 14. Furthermore, a ceramic protective film paste 170 is printed so as to extend over a portion of the surface of the printed conductive paste 142 and the surface of the ceramic green sheet 110. At this time, the ceramic protective film paste 170 is formed so as to surround the outer edge of the conductive paste 142 that will become the first electrode. As a result, the conductive paste 142 that will become the first electrode and the conductive paste 142 that will become the second electrode are printed on the surface of the ceramic green sheet 110, resulting in a laminate sheet 100G in which the ceramic protective film paste 170 is printed so as to surround the outer edge of the conductive paste 142 that will become the first electrode. 16, a portion of the conductive paste 142 printed on the surface of the ceramic green sheet 110 overlaps with the conductive paste 142 printed on the surface of the ceramic green sheet 110 in FIG.

[0120] At this time, in the process of producing the laminate described below, when laminate sheet 100G and laminate sheet 100C are laminated, at least a portion of ceramic protective film paste 170 printed on conductive paste 142 is positioned so as to overlap conductive paste 131 which serves as the connection terminal.

[0121] 17 is a diagram schematically illustrating an example of a process for stacking prepared laminate sheets. As shown in FIG. 17, laminate sheets 100A to 100G prepared in the above process are stacked in a predetermined order. In FIG. 17, from the top, laminate sheet 100C, laminate sheet 100C, laminate sheet 100G, laminate sheet 100D, laminate sheet 100D, laminate sheet 100F, laminate sheet 100B, and laminate sheet 100A are stacked in this order to form laminate body 200.

[0122] FIG. 18 is a diagram schematically illustrating an example of a process for compressing a laminate. As shown in FIG. 18 , a laminate 200 is compressed to obtain a compressed body 210. Because the ceramic protective film paste 170 is printed so as to cover the outer edge of the conductive paste 142 that will become the first electrode, during compression bonding, the portion of the conductive paste 142 that will become the first electrode and that overlaps with the ceramic protective film paste 170 bends toward the inside of the substrate (toward the bottom of the page) and deforms so as to become thinner toward the outside. This causes the shape of the conductive paste 142 to change to a shape similar to the first electrode 11 shown in FIG. 3 .

[0123] The pressure and temperature when the laminate is pressed together can be set arbitrarily according to the design.

[0124] 19 is a diagram schematically illustrating an example of a process for firing the pressure-bonded body 210. As shown in FIG. 19, firing the pressure-bonded body 210 sinters the conductive paste filled in the through holes and the printed conductive paste, and also progresses the sintering of the ceramic green sheets, resulting in a fired body 220.

[0125] At this time, the ceramic green sheets are sintered to form the substrate 10, and the conductive paste filled in the constraining layer sheets is sintered to form the connection terminals 30. The conductive paste filled or printed on the ceramic green sheets is sintered to form the first electrode 11, the second electrode 14, the via conductors 15, the wiring 17, and the third electrode 19. Furthermore, the ceramic green sheets 110 and the ceramic protective film paste 170 are sintered to form the substrate 10 and the ceramic protective film 70.

[0126] Only a portion of the surface of the first electrode 11 is joined to the connection terminal 30. Of the surface of the first electrode 11, the portion that is joined to the connection terminal 30 is the first portion.

[0127] A ceramic protective film 70 is provided on a portion of the surface of the first electrode 11. Specifically, the ceramic protective film 70 is provided between the second portion of the first electrode and the connection terminal.

[0128] Furthermore, if the ceramic material constituting the ceramic green sheet 110 and the ceramic material constituting the ceramic protective film paste 170 have the same material composition, it may become impossible to distinguish between the ceramic protective film in the fired body 220 and the ceramic material constituting the substrate.

[0129] 17 and 18 , in the pressure-bonded body 210, the constraining layer sheet 130 is laminated on the surface of the ceramic protective film paste 170, and therefore, during firing, some of the components of the hard-to-sinter ceramic that constitutes the constraining layer sheet 130 may diffuse toward the ceramic protective film paste 170. In such a case, by checking the area outside the second portion of the first electrode by elemental mapping or the like where the content of the elements that constitute the hard-to-sinter ceramic is high, it may be possible to indirectly identify the portion where the ceramic protective film is formed.

[0130] The firing can be performed using a firing furnace such as a batch furnace, a belt furnace, etc. The firing temperature is not particularly limited, but is preferably 800°C or higher and 1000°C or lower.

[0131] 20 is a diagram schematically illustrating an example of a step of removing the constraining layer. Next, as shown in FIG. 20, the constraining layer 190 (residue of the constraining layer sheet) is removed by cleaning. By removing the constraining layer, the substrate 10 (object to be cleaned 230) is obtained, with the connection terminals 30 exposed on one main surface 10a.

[0132] The method for removing the constraining layer is not particularly limited, but a known method such as sandblasting can be used.

[0133] 21 is a diagram schematically illustrating an example of a process for forming a plating film. Next, as shown in FIG. 21 , a plating film is formed on the surface of the substrate 10. As a result, a plating film 23 is formed on the side and top surfaces of the connection terminal 30, the surface of the second electrode 14, and the surface of the third electrode 19. Note that, because the surface of the first portion of the first electrode 11 is joined to the connection terminal 30 and the surface of the second portion is provided with a ceramic protective film 70, the plating film 23 is not formed on the surface of the first electrode 11.

[0134] 22 is a diagram schematically illustrating an example of a process for mounting an electronic component on one main surface of a substrate. Next, as shown in FIG. 22 , the electronic component is mounted on one main surface 10 a of the substrate 10 using second electrodes 14. Solder 50 is provided between the second electrodes 14 and the electronic component 40.

[0135] 23 is a cross-sectional view schematically showing an example of a process for encapsulating an electronic component. Subsequently, as shown in FIG. 23, encapsulation resin 26 is applied onto one main surface 10a of the substrate. As a result, electronic component 40 is encapsulated by encapsulation resin 26.

[0136] Fig. 24 is a cross-sectional view schematically showing an example of a step of grinding the surface of the sealing resin. Next, as shown in Fig. 24, the surface of the sealing resin 26 is ground to expose the connection terminals 30. In Fig. 24, the top surface of the electronic component 40 is also exposed, but the top surface of the electronic component 40 does not have to be exposed. Through the above steps, the circuit module 1 described in Fig. 2 is obtained.

[0137] In the above, the ceramic green sheets and the constraining layer sheets are each formed on a carrier film, and then peeled from the carrier film and laminated together. However, instead of the above method, for example, a method may be adopted in which a ceramic green sheet is formed on the surface of a carrier film, and then a constraining layer sheet is formed on the surface of the ceramic green sheet. The method for forming the constraining layer sheet on the surface of the carrier film can be the same as the method for forming the constraining layer sheet on the surface of the carrier film.

[0138] In addition to the above steps, a step of forming a plating film on the surface of the connection terminal exposed on the second main surface of the first resin layer may be performed. FIG. 25 is a cross-sectional view schematically showing the step of forming a plating film on the surface of the connection terminal. As shown in FIG. 25, a plating film 24 may be formed on the surface of the connection terminal 30. The plating film 24 can be formed, for example, by performing a plating process on the circuit module 1 shown in FIG. 24. The plating film 24 may be formed of, for example, Ni and / or Sn. By adding the above steps, a plating film can be formed on the surface of the connection terminal exposed on the second main surface of the first resin layer.

[0139] In addition to the above steps, a step of mounting electronic components on the other main surface of the substrate and sealing it with a sealing resin to form a second resin layer may be performed.

[0140] 26 is a cross-sectional view schematically showing a process of mounting an electronic board on the other main surface of the substrate. Next, as shown in FIG. 26, electronic components 41 and 42 are mounted on the other main surface 10b of the substrate 10. The electronic components 41 and 42 are each connected to a third electrode 19 provided on the other main surface 10b of the substrate 10 via solder 50.

[0141] 27 is a cross-sectional view schematically showing an example of a process for sealing the electronic components. Next, as shown in FIG. 27 , sealing resin 63 is applied onto the other main surface 10b of substrate 10. As a result, electronic components 41 and 42 are sealed with sealing resin 63.

[0142] 28 is a cross-sectional view schematically showing an example of a step of grinding the surface of the sealing resin. Next, as shown in FIG. 28, the surface of the sealing resin 63 is ground to adjust the shape of the second resin layer 60. Through the above steps, the electronic components 41 and 42 are mounted on the other main surface 10b of the substrate 10 and sealed with the sealing resin 63, thereby obtaining the circuit module 2 on which the second resin layer 60 is formed.

[0143] This specification describes the following:

[0144] The present disclosure (1) is a circuit module comprising: a substrate having one main surface and another main surface; and a connection terminal arranged on the one main surface side of the substrate; wherein a first electrode is provided on the one main surface of the substrate; and on the one main surface side of the substrate, a portion of the end face of the connection terminal is joined to a portion of the surface of the first electrode; when the first electrode is viewed from the thickness direction, a portion of the surface of the first electrode that is joined to the connection terminal is defined as a first portion, and a portion that surrounds the periphery of the first portion and is not joined to the connection terminal of the first electrode is defined as a second portion; and a ceramic protective film made of a ceramic material is provided between the surface of the second portion and the portion of the end face of the metal pillar that is not joined to the first portion.

[0145] The present disclosure (2) is the circuit module according to the present disclosure (1), wherein the area of ​​the second portion is larger than the area of ​​the first portion when viewed in the thickness direction.

[0146] The present disclosure (3) is a circuit module described in the present disclosure (1) or (2), in which, when viewed from the thickness direction, the area of ​​the first electrode on the side opposite to the connection terminal is smaller than the area of ​​the connection terminal.

[0147] The present disclosure (4) is a circuit module described in the present disclosure (1) or (2), in which, when viewed from the thickness direction, the area of ​​the first electrode on the side opposite the connection terminal is larger than the area of ​​the connection terminal.

[0148] The present disclosure (5) is a circuit module of any combination with any of the present disclosures (1) to (4), wherein the shape of the first part when viewed from the thickness direction comprises a circular portion and a pair of protrusions protruding outward from the circular portion, and the pair of protrusions are arranged in positions facing each other across the center of gravity of the circular portion.

[0149] The present disclosure (6) is a circuit module of any combination with any of the present disclosures (1) to (5), in which the first portion of the first electrode is flush with the one main surface of the substrate, and the second portion of the first electrode is buried under the ceramic protective film.

[0150] 1, 2 Circuit module 10 Substrate 10a One main surface of the substrate 10b Other main surface of the substrate 11, 12, 13 First electrode 11a, 12a, 13a First portion of the first electrode 11b, 12b, 13b Second portion of the first electrode 11b １ Surface 11b of the second portion on the connection terminal side ２ Surface 11b of the second portion opposite to the connection terminal ３ End 13a of the first electrode in the width direction １ First part circular portion 13a ２ , 13a ３ 1. Protruding portion of first portion 14 Second electrode 15 Via conductor 17 Wiring 19 Third electrode 20 First resin layer 20a First main surface of first resin layer 20b Second main surface of first resin layer 23, 24 Plating film 26 Sealing resin 30 Connection terminal 40, 41, 42 Electronic component 50 Solder 60 Second resin layer 63 Sealing resin 70 Ceramic protective film 90 Carrier film 100A, 100B, 100C, 100D, 100E, 100F, 100G Laminated sheet 110 Ceramic green sheet 130 Constraining layer sheet 131, 140 Filled conductive paste 142 Printed conductive paste 150 Ceramic paste 170 Ceramic protective film paste 180, 181 Through hole 190 Constraining layer 200 Laminate 210 Compressed body 220 Sintered body 230 Body to be cleaned G Center of gravity of first electrode h ３０ Height of the connection terminal: L Extension surface of the surface of the first part of the first electrode opposite to the connection terminal: R １１ａ Diameter of the first part R ３０ Diameter of connection terminal W １１ｂ Second part width

Claims

1. A circuit module comprising: a substrate having one main surface and another main surface; and a connection terminal arranged on the one main surface side of the substrate, wherein a first electrode is provided on the one main surface of the substrate, and on the one main surface side of the substrate, part of an end face of the connection terminal is joined to a part of a surface of the first electrode, when the first electrode is viewed in the thickness direction, a part of the surface of the first electrode that is joined to the connection terminal is defined as a first part, and a part that surrounds the periphery of the first part and is not joined to the connection terminal of the first electrode is defined as a second part, and a ceramic protective film made of a ceramic material is provided between the surface of the second part and the part of the end face of the connection terminal that is not joined to the first part.

2. The circuit module according to claim 1, wherein an area of ​​said second portion is larger than an area of ​​said first portion when viewed in said thickness direction.

3. The circuit module according to claim 1 or 2, wherein, when viewed in the thickness direction, the area of ​​the first electrode on the side opposite to the connection terminal is smaller than the area of ​​the connection terminal.

4. The circuit module according to claim 1 or 2, wherein, when viewed in the thickness direction, the area of ​​the first electrode on the side opposite to the connection terminal is larger than the area of ​​the connection terminal.

5. A circuit module as described in any one of claims 1 to 4, wherein the shape of the first portion when viewed in the thickness direction comprises a circular portion and a pair of protrusions protruding outward from the circular portion, and the pair of protrusions are positioned opposite each other across the center of gravity of the circular portion.

6. A circuit module as described in any one of claims 1 to 5, wherein the first portion of the first electrode is flush with the one main surface of the substrate, and the second portion of the first electrode is buried under the ceramic protective film.

Images