Wiring boards and functional devices

Abstract

To provide a technique that makes it possible to achieve excellent connection reliability in connecting a functional device and a wiring board.SOLUTION: A wiring board 10 includes an insulating layer 114, a conductor pattern 112, and a plurality of junction electrodes 115. The insulating layer 114 has a first main surface and a second main surface, which is the back surface thereof and is provided with a plurality of through-holes each extending from the first main surface to the second main surface. The conductor pattern 112 is provided on the first main surface and blocks openings on the first main surface side of the plurality of through-holes. The plurality of junction electrodes 115 embedding each of the plurality of through-holes and protruding like columns from the second main surface, each top surface including a first region provided with a recess and a second region surrounding the first region.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a multilayer wiring board and a functional device.

Background Art

[0002] Recently, with the development of the electronics industry, there has been a demand for higher performance, higher functionality, and miniaturization of electronic components. Along with this, in surface mounting technologies such as SIP (System in package) and 3D packages, the demands for high integration, thinning, and fine circuit patterning have increased rapidly.

[0003] For example, in the surface mounting of semiconductor chips onto a substrate, the flip chip bonding method is often used to connect the semiconductor chip to the mother board. In the flip chip bonding method, external connection terminals (i.e., bumps) with a height of several tens of μm to several hundreds of μm, made of gold, solder, or other metals, etc., are formed on the semiconductor chip. Then, the semiconductor chip with the bumps formed is flipped over so that the surface on which the bumps are formed faces the substrate, and it is mounted on the substrate.

[0004] Also, in recent years, semiconductor chips have advanced in the miniaturization and high integration of conductor patterns. Under such circumstances, a method of connecting a semiconductor element to a mother board via a wiring board, for example, a wiring board for FC - BGA (Flip Chip - Ball Grid Array) (hereinafter also referred to as an FC - BGA board), is adopted.

[0005] Conventionally, in the manufacture of a wiring board for FC - BGA, a solder resist having through - holes at the positions of electrode pads is provided, and connection terminals for connecting the wiring board for FC - BGA and a semiconductor chip are formed in these through - holes. The connection terminals are made of a metal material such as solder and have a height of several tens of μm.

[0006] The flip chip bonding method used here has been developed to use metal posts in order to narrow the pitch of the connection terminals of the semiconductor chip.

[0007] In the manufacturing of FC-BGA wiring boards using metal posts, metal posts with a diameter of several tens of micrometers and a height of several tens of micrometers are formed in through-holes of the solder resist, and solder bumps are formed on top of the metal posts. By joining the metal posts of the FC-BGA wiring board and the metal posts of the semiconductor chip via these solder bumps, a structure is obtained in which the distance between the semiconductor chip and the wiring board is several tens of micrometers. Examples of the use of metal posts are disclosed, for example, in Patent Documents 1 and 2.

[0008] Using metal posts allows for narrower terminal pitches, facilitates underfill material installation, and improves heat dissipation performance. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2010-129996 [Patent Document 2] Japanese Patent Publication No. 2020-188139 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention aims to provide a technology that enables excellent connection reliability in the connection between a functional device and a wiring board. [Means for solving the problem]

[0011] According to one aspect of the present invention, a wiring board is provided comprising: an insulating layer having a first main surface and a second main surface which is the back surface thereof, and having a plurality of through holes extending from the first main surface to the second main surface; a conductor pattern provided on the first main surface which closes the openings of the plurality of through holes on the first main surface side; and a plurality of bonding electrodes which each fill the plurality of through holes and protrude columnarly from the second main surface, the upper surface of each bonding electrode including a first region having a recess and a second region surrounding the first region.

[0012] According to another aspect of the present invention, a wiring board is provided in which the second region is flat.

[0013] Alternatively, according to another aspect of the present invention, the second region provides a wiring board relating to the side in which the outer edge is positioned higher than the inner edge.

[0014] Alternatively, according to another aspect of the present invention, the second region provides a wiring board relating to the side in which the inner edge is positioned higher than the outer edge.

[0015] According to yet another aspect of the present invention, a wiring board is provided relating to any of the above aspects, wherein the ratio R2 / R1 of the diameter R2 of the recess to the diameter R1 of the upper surface is in the range of 0.05 to 0.99.

[0016] According to yet another aspect of the present invention, a wiring board is provided relating to any of the above aspects, wherein the ratio D / R2 of the depth D of the recess to the diameter R2 of the recess is in the range of 0.004 to 0.9.

[0017] According to yet another aspect of the present invention, a wiring board is provided relating to any of the above aspects, wherein, among the plurality of bonding electrodes, those located in the peripheral portion surrounding the central portion of the insulating layer have a greater distance from the center of the recess to the center of the upper surface compared to those located in the central portion.

[0018] According to yet another aspect of the present invention, a wiring board is provided relating to any of the above-mentioned sides, wherein the periphery portion of the plurality of bonding electrodes is such that the position of the center of the recess is shifted away from the central portion with respect to the position of the center of the upper surface.

[0019] According to yet another aspect of the present invention, a wiring board relating to any of the above aspects is provided, further comprising an organic layer covering the sides of the portions of the plurality of bonding electrodes that protrude from the insulating layer.

[0020] According to yet another aspect of the present invention, a wiring board is provided comprising a plurality of bonding material layers provided on the upper surfaces of the plurality of bonding electrodes, wherein each of the plurality of bonding material layers relates to any of the above-mentioned sides that protrude outward from the recess at the location of the recess.

[0021] According to yet another aspect of the present invention, a wiring board is provided in which one or more of the plurality of bonding material layers are provided only at the location of the recess, according to any of the above aspects.

[0022] Alternatively, according to yet another aspect of the present invention, a wiring board is provided relating to any of the above aspects, wherein one or more of the plurality of bonding material layers include a first portion provided on the first region and a second portion provided on the second region.

[0023] According to yet another aspect of the present invention, a wiring board according to any of the above aspects is provided, wherein each of the plurality of bonding material layers is made of solder, and the second region is made of copper or nickel.

[0024] According to yet another aspect of the present invention, a functional device is provided comprising a wiring board according to any of the above aspects, a functional device body, and a plurality of bonding electrodes protruding from the functional device body, wherein the plurality of bonding electrodes of the functional device each comprises a functional device interposed between the plurality of bonding electrodes of the wiring board and the functional device body, and a plurality of bonding material layers interposed between the plurality of bonding electrodes of the wiring board and the plurality of bonding electrodes of the functional device, respectively.

[0025] Here, a "functional device" is a device that operates by being supplied with at least one of power and an electrical signal, a device that outputs at least one of power and an electrical signal by an external stimulus, or a device that operates by being supplied with at least one of power and an electrical signal and outputs at least one of power and an electrical signal by an external stimulus. The functional device is in the form of a chip, such as a semiconductor chip or a chip in which circuits and elements are formed on a substrate made of a material other than semiconductor, such as a glass substrate. The functional device can include, for example, one or more of a large-scale integrated circuit (LSI), a memory, an imaging device, a light-emitting device, and MEMS (Micro Electro Mechanical Systems). MEMS is, for example, one or more of a pressure sensor, an acceleration sensor, a gyro sensor, an inclination sensor, a microphone, and an acoustic sensor. According to one example, the functional device is a semiconductor chip including an LSI.

[0026] According to still another aspect of the present invention, there is provided a packaged device in which each of the plurality of bonding electrodes of the functional device is related to a side surface including a third region provided with a recess and a fourth region surrounding the third region on the upper surface thereof.

[0027] According to yet another aspect of the present invention, a method for manufacturing a wiring board is provided, comprising: a laminated structure including an insulating layer and a conductor pattern, wherein the insulating layer has a first main surface and a second main surface which is its back surface, and is provided with a plurality of first through holes extending from the first main surface to the second main surface, and the conductor pattern is provided on the first main surface, forming a laminated structure that closes the openings of the plurality of first through holes on the first main surface side; a resist layer is provided on the second main surface, having a plurality of second through holes that communicate with the plurality of first through holes, respectively; a metal material is deposited in the plurality of first through holes and the plurality of second through holes by a plating method to fill the plurality of first through holes and form a plurality of bonding electrodes that protrude columnarly from the second main surface; the resist layer is removed; and a portion of the metal material is removed from the upper surface of each of the plurality of bonding electrodes to create a first region with a recess and a second region surrounding the first region on the upper surface.

[0028] According to yet another aspect of the present invention, a method for manufacturing a wiring board is provided, relating to the aspect of removing the portion of the metal material at the location of the first region.

[0029] Alternatively, according to yet another aspect of the present invention, a method for manufacturing a wiring board is provided, in which the metal material is deposited such that the upper surface becomes concave, and a portion of the metal material is removed at the location of the second region.

[0030] According to yet another aspect of the present invention, a laminated structure comprising an insulating layer and a conductor pattern, wherein the insulating layer has a first main surface and a second main surface which is its back surface, and is provided with a plurality of first through holes extending from the first main surface to the second main surface, the conductor pattern is provided on the first main surface and forms a laminated structure that closes the openings of the plurality of first through holes on the first main surface side, a first resist layer is provided on the second main surface having a plurality of second through holes which communicate with the plurality of first through holes, and a metallic material is deposited in the plurality of first through holes and the plurality of second through holes by a plating method to fill the plurality of first through holes, and the second A method for manufacturing a wiring substrate is provided, comprising: forming a plurality of first conductor portions protruding columnarly from a main surface; removing the first resist layer; exposing a region along the edge of the upper surface of each of the plurality of first conductor portions and providing a second resist layer that covers the region surrounded by this region; further depositing a metallic material on the exposed region by a plating method to form a second conductor portion on each of the first conductor portions, thereby forming a plurality of bonding electrodes, each including the first conductor portion and the second conductor portion, and each upper surface including a first region with a recess and a second region surrounding the first region; and removing the second resist layer.

[0031] A method for manufacturing a wiring board according to any of the above aspects is provided, further comprising forming a plurality of bonding material layers on the upper surfaces of the plurality of bonding electrodes, each protruding outward from the recess at the location of the recess.

[0032] A method for manufacturing a packaged device is provided, comprising: preparing a functional device comprising a functional device body, a plurality of bonding electrodes protruding from the functional device body, and a plurality of bonding material layers provided on the upper surfaces of the plurality of bonding electrodes; preparing a wiring board according to any of the above aspects; and butting the plurality of bonding material layers of the functional device with the plurality of bonding material layers of the wiring board, and applying heat to them in this state to bond the plurality of bonding electrodes of the functional device with the plurality of bonding electrodes of the wiring board to each other.

[0033] According to yet another aspect of the present invention, a functional device is provided comprising a functional device body and a plurality of bonding electrodes protruding from the functional device body, each bonding electrode having an upper surface that includes a first region having a recess and a second region surrounding the first region.

[0034] According to yet another aspect of the present invention, a functional device is provided comprising a plurality of bonding material layers provided on the upper surfaces of the plurality of bonding electrodes, wherein each of the plurality of bonding material layers has a side surface that protrudes outward from the recess at the location of the recess.

[0035] A wiring board is provided, comprising: an insulating layer having a first main surface and a second main surface which is the back surface thereof, and having a plurality of through holes extending from the first main surface to the second main surface; a conductor pattern provided on the first main surface that closes the openings of the plurality of through holes on the first main surface side; and a plurality of bonding electrodes that fill the plurality of through holes and protrude columnarly from the second main surface; and a functional device relating to the above aspect, wherein the plurality of bonding electrodes of the functional device each comprises a functional device interposed between the plurality of bonding electrodes of the wiring board and the functional device, and a plurality of bonding material layers interposed between the plurality of bonding electrodes of the wiring board and the plurality of bonding electrodes of the functional device.

[0036] A method for manufacturing a functional device is provided, comprising: providing a resist layer having a plurality of through holes on a functional device body; depositing a metal material in the plurality of through holes by a plating method to form a plurality of bonding electrodes protruding columnarly from the functional device body; removing the resist layer; and removing a portion of the metal material from the upper surface of each of the plurality of bonding electrodes to create a first region with a recess and a second region surrounding the first region on the upper surface.

[0037] A further aspect of the present invention provides a method for manufacturing a functional device, comprising: providing a first resist layer having a plurality of through-holes on a functional device body; depositing a metal material in the plurality of through-holes by a plating method to form a plurality of first conductor portions protruding columnarly from the functional device body; removing the first resist layer; exposing a region along the edge of the upper surface of each of the plurality of first conductor portions and providing a second resist layer covering the region surrounded by this region; further depositing a metal material on the exposed region by a plating method to form a second conductor portion on each of the first conductor portions, thereby forming a plurality of bonding electrodes, each including the first conductor portion and the second conductor portion, the upper surface of which includes a first region with a recess and a second region surrounding the first region; and removing the second resist layer.

[0038] A method for manufacturing a functional device according to any of the above aspects is provided, further comprising forming a plurality of bonding material layers on the upper surfaces of the plurality of bonding electrodes, each protruding outward from the recess at the location of the recess.

[0039] According to yet another aspect of the present invention, a method for manufacturing a packaged device is provided, comprising: preparing a wiring board having a first main surface and a second main surface which is the back surface thereof, and having a plurality of through holes extending from the first main surface to the second main surface; a conductor pattern provided on the first main surface that closes the openings of the plurality of through holes on the first main surface side; a plurality of bonding electrodes that fill the plurality of through holes and protrude columnarly from the second main surface; and a plurality of bonding material layers provided on the upper surfaces of the plurality of bonding electrodes; preparing a functional device according to the above aspect; and butting the plurality of bonding material layers of the functional device with the plurality of bonding material layers of the wiring board, and applying heat to them in this state to bond the plurality of bonding electrodes of the functional device with the plurality of bonding electrodes of the wiring board to each other. [Brief explanation of the drawing]

[0040] [Figure 1] Figure 1 is a schematic cross-sectional view showing a wiring board according to the first embodiment of the present invention. [Figure 2] Figure 2 is a plan view showing a magnified portion of the wiring board in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of the structure in Figure 2 along line III-III. [Figure 4] Figure 4 is a schematic cross-sectional view showing one step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing other steps in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 6] Figure 6 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 7] Figure 7 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 8] Figure 8 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 9]Figure 9 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 10] Figure 10 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 11] Figure 11 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 12] Figure 12 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 13] Figure 13 is a schematic cross-sectional view showing yet another step in the manufacturing method of a wiring board according to the first embodiment of the present invention. [Figure 14] Figure 14 is a schematic cross-sectional view showing a packaging device according to the first embodiment of the present invention. [Figure 15] Figure 15 is a schematic cross-sectional view showing one step in the manufacturing method of a packaged device according to a comparative example. [Figure 16] Figure 16 is a schematic cross-sectional view showing an example of a structure obtained by the process shown in Figure 15. [Figure 17] Figure 17 is a schematic cross-sectional view showing one step in the manufacturing method of a packaged device according to the first embodiment of the present invention. [Figure 18] Figure 18 is a schematic cross-sectional view showing an example of a structure obtained by the process in Figure 17. [Figure 19] Figure 19 is a cross-sectional view showing an enlarged portion of the wiring board according to the first modified example. [Figure 20] Figure 20 is a cross-sectional view showing an enlarged portion of the wiring board relating to the second modified example. [Figure 21] Figure 21 is a cross-sectional view showing an enlarged portion of the wiring board relating to the third modified example. [Figure 22] Figure 22 is an enlarged cross-sectional view showing a part of a functional device according to the second embodiment of the present invention. [Figure 23] Figure 23 is a cross-sectional view showing an example of the structure that a packaged device containing the functional device shown in Figure 22 may have. [Figure 24] Figure 24 is a cross-sectional view showing another example of the structure that a packaged device containing the functional device shown in Figure 22 may have. [Figure 25] Figure 25 is a plan view showing an enlarged portion of the wiring board relating to the fourth modified example. [Figure 26] Figure 26 is a plan view showing a magnified portion of the wiring board in Figure 25. [Figure 27] Figure 27 is a schematic cross-sectional view showing one step in the manufacturing method of a wiring board according to the fifth modified example. [Figure 28] Figure 28 is a schematic cross-sectional view showing other steps in the manufacturing method of a wiring board according to the fifth modified example. [Modes for carrying out the invention]

[0041] Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are more specific to any of the above embodiments. The embodiments shown below are examples that embody the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the material, shape, structure, and arrangement of the components described below. Various modifications can be made to the technical idea of ​​the present invention within the technical scope defined by the claims described in the patent claims.

[0042] In the drawings referenced in the following description, components with similar or identical functions are given the same reference numerals. It should be noted that the drawings are schematic, and the relationships between dimensions in the thickness direction and dimensions perpendicular to the thickness direction (i.e., in-plane direction), as well as the relationships between dimensions in the thickness direction of multiple layers, may differ from reality. Therefore, specific dimensions should be determined by referring to the following description. It should also be noted that the dimensional relationships between two or more components may differ across multiple drawings.

[0043] In this disclosure, the term "upper surface," when used in reference to a bonding electrode, refers to the region of the bonding electrode's surface that faces other bonding electrodes that are abutted against it during bonding. Furthermore, the terms "upper surface" and "lower surface," when used in reference to a plate-like member or a layer contained therein, refer to its two main surfaces: the surface perpendicular to the thickness direction and having the largest area, and its back surface, which are shown as the upper and lower surfaces in the drawings, respectively. When the term "upper surface" is used in reference to a portion protruding from the base material, it refers to the surface of that portion that includes the part furthest from the base material. Finally, the term "side surface" refers to a surface that is perpendicular to or inclined to the above-mentioned surfaces.

[0044] Furthermore, in this disclosure, the phrase "AA on BB" is used independently of the direction of gravity. The state specified by the phrase "AA on BB" includes the state in which AA is in contact with BB. The phrase "AA on BB" does not exclude the presence of one or more other components between AA and BB.

[0045] <1> First Embodiment <1.1> Wiring board Figure 1 is a schematic cross-sectional view showing a wiring board according to the first embodiment of the present invention. Figure 2 is a plan view showing an enlarged portion of the wiring board of Figure 1. Figure 3 is a cross-sectional view along line III-III of the structure in Figure 2.

[0046] The wiring board 10 shown in Figures 1 to 3 is a multilayer wiring board, specifically an FC-BGA board. Functional devices (not shown) are bonded to the wiring board 10. The wiring board 10 is also bonded to a motherboard (not shown). In other words, the wiring board 10 mediates the bonding of functional devices to the motherboard.

[0047] The wiring board 10 may be an interposer to which functional devices are bonded, as well as to an FC-BGA board. In this case, the wiring board 10, together with the FC-BGA board, mediates the bonding of functional devices to the motherboard.

[0048] The wiring board 10 may be bonded to the motherboard or FC-BGA board by wire bonding. Furthermore, if the wiring board 10 is an interposer, the wiring board to which the wiring board 10 is bonded may be bonded to the motherboard by flip-chip bonding or by wire bonding.

[0049] The wiring board 10 includes an insulating layer 111, a conductor pattern 112, insulating layers 113 and 114, a bonding electrode 115, a bonding material layer 116, and a conductor layer 117.

[0050] The insulating layer 111 and the conductor pattern 112 form a multilayer wiring structure. The multilayer wiring structure includes multiple layers 11 stacked on top of each other. Each layer 11 includes an insulating layer 111 and a conductor pattern 112. Here, the multilayer wiring structure includes two layers 11, but the multilayer wiring structure may include three or more layers 11.

[0051] The insulating layer 111 and the conductor pattern 112 are stacked alternately. The insulating layer 111 is, for example, an insulating resin layer. The insulating layer 111 is provided with a plurality of through holes.

[0052] The conductor pattern 112 is made of a metallic material. The metallic material is a metal such as copper, aluminum, and nickel, or an alloy containing one or more of these. Here, as an example, the conductor pattern 112 is made of copper.

[0053] The conductor pattern 112 includes pad sections, land sections, wiring sections, and via sections. The pads are positioned on the upper and lower surfaces of the multilayer wiring structure. The pads are located at the positions of through holes provided in the adjacent insulating layer 111. The distance between the pads positioned on the upper surface is shorter than the distance between the pads positioned on the lower surface.

[0054] The land portion is positioned between the insulating layers 111. The pad portion is positioned at the location of the through-hole provided in the insulating layers 111 that sandwich it from above and below.

[0055] The wiring sections are arranged between the insulating layers 111. Each wiring section is connected to two land sections interposed between the insulating layers 111.

[0056] The via section embeds a through-hole provided in the insulating layer 111. Each via section is connected to an adjacent pad section and land section with the insulating layer 111 in between.

[0057] The insulating layer 113 is provided on the underside of the multilayer wiring structure. The insulating layer 113 is, for example, an insulating resin layer. Through holes are provided in the insulating layer 113 at the positions of the pad portions located on the underside of the multilayer wiring structure.

[0058] The insulating layer 114 is provided on the upper surface of the multilayer wiring structure. The lower and upper surfaces of the insulating layer 114 are the first main surface and the second main surface, which is the back surface of the first main surface, respectively. The insulating layer 114 is, for example, an insulating resin layer. The insulating layer 114 is provided with through holes that extend from the first main surface to the second main surface at the positions of the pad portions located on the upper surface of the multilayer wiring structure. That is, the portion of the conductor pattern 112 that is located on the upper surface of the multilayer wiring structure blocks the opening on the first main surface side of the through holes provided in the insulating layer 114.

[0059] The bonding electrode 115 is made of a metallic material with a higher melting point than the material of the bonding layer 116. This metallic material is a metal such as copper, aluminum, or nickel, or an alloy containing one or more of these. The bonding electrode 115 may have a single-layer structure or a multi-layer structure. Here, as an example, the bonding electrode 115 is made of copper.

[0060] The junction electrodes 115 fill the through holes provided in the insulating layer 114 and protrude columnarly from the second main surface. In other words, the junction electrodes 115 are metal posts.

[0061] Here, the portion of the bonding electrode 115 that protrudes from the second main surface has a substantially cylindrical shape, with its height equal to the thickness direction of the wiring board 10. The portion of the bonding electrode 115 that protrudes from the second main surface may have other shapes, such as a triangular prism shape, a square prism shape, a hexagonal prism shape, or an octagonal prism shape.

[0062] The height H of the portion of the junction electrode 115 that protrudes from the second main surface is, for example, in the range of 10 to 40 μm. The diameter R1 of the portion of the junction electrode 115 that protrudes from the second main surface is, for example, in the range of 20 to 110 μm. The ratio H / R1 of height H to diameter R1 is, for example, in the range of 1 / 11 to 2.

[0063] The minimum center-to-center distance P of the bonding electrodes 115 is preferably in the range of 50 to 200 μm, and more preferably in the range of 70 to 130 μm. As will be described later, in this wiring board 10, even if the minimum center-to-center distance P is reduced, short circuits between the bonding electrodes 115 via the bonding material layer are unlikely to occur.

[0064] The upper surface of the bonding electrode 115 includes a first region with a recess and a second region surrounding the first region. The contour of the first region is equal to the contour of the opening of the recess. The second region is flat. The second region is substantially perpendicular to the thickness direction of the wiring board 10.

[0065] Here, the opening of the recess and the upper surface of the bonding electrode 115 are similar in shape, and their center positions coincide. Specifically, the upper surface of the bonding electrode 115 is circular, and the opening of the recess is a circular shape concentric with the upper surface of the bonding electrode 115. The opening of the recess does not have to be similar in shape to the upper surface of the bonding electrode 115. Also, the shape of the opening of the recess may be a polygon such as a triangle, square, hexagon, or octagon. If the shape of the opening of the recess is a polygon, it is preferable that all interior angles of this polygon are 90° or more. In this case, compared to the case where the shape of the opening of the recess is a polygon with acute angles, large stresses are not applied to the corners, and higher connection reliability can be achieved.

[0066] The ratio R2 / R1 of the diameter R2 of the recess to the diameter R1 of the upper surface of the bonding electrode 115 is preferably in the range of 0.05 to 0.99, and more preferably in the range of 0.6 to 0.8. Increasing the ratio R2 / R1 allows for a larger amount of bonding material to be present depending on the position of the recess. However, increasing the ratio R2 / R1 shortens the distance W from the recess to the upper edge of the bonding electrode 115. Therefore, when the ratio R2 / R1 is increased, it is desirable to appropriately set the amount of bonding material so that an excess amount of bonding material does not protrude from between the bonding electrodes when bonding the wiring board 10 and the functional device.

[0067] The depth D of the recess is preferably in the range of 0.5 to 15 μm, and more preferably in the range of 1 to 5 μm. The ratio D / R2 of depth D to diameter R2 is preferably in the range of 0.004 to 0.9, and more preferably in the range of 0.01 to 0.17. Increasing the depth D or the ratio D / R2 makes it less likely for the bonding material to move from the position of the recess to another position when the bonding material layer 116 is provided, and therefore the variation in the relative position of the bonding material layer 116 with respect to the recess is reduced. In addition, increasing the depth D or the ratio D / R2 allows for an increase in the amount of bonding material interposed between the bonding electrodes when the wiring board 10 and the functional device are bonded. When the amount of bonding material is large, connection failures caused by variations in the height of the bonding electrodes and connection failures caused by differences in the coefficient of linear expansion between the wiring board 10 and the functional device 20 are less likely to occur. However, if the amount of bonding material interposed between the bonding electrodes of the wiring board 10 and the bonding electrodes of the functional device is increased, the resistance between those bonding electrodes may increase.

[0068] Each bonding layer 116 is provided on the upper surface of the bonding electrode 115. One or more bonding layers 116, for example, all of the bonding layers 116, are provided only in the recessed areas. The bonding layer 116 is made of a metal material with a lower melting point than the metal material constituting the bonding electrode 115, such as solder.

[0069] Each of the bonding material layers 116 protrudes outward from the recess provided on the upper surface of the bonding electrode 115. The protruding portion of the bonding material layer 116 has a height of preferably 5 to 50 μm, and more preferably 10 to 30 μm, relative to the upper surface of the bonding electrode 115. Increasing this height allows for a larger amount of bonding material to be interposed between the bonding electrodes when bonding the wiring board 10 and the functional device. When there is a large amount of bonding material, connection failures caused by variations in the height of the bonding electrodes and connection failures caused by differences in the coefficient of thermal expansion between the wiring board 10 and the functional device 20 are less likely to occur. However, increasing the amount of bonding material interposed between the bonding electrodes of the wiring board 10 and the functional device may increase the resistance between those bonding electrodes.

[0070] The conductor layer 117 is interposed between the junction electrode 115 and the insulating layer 114, and between the junction electrode 115 and the conductor pattern 112. The conductor layer 117 is a seed layer that acts as a power supply layer in the electroplating deposition of the junction electrode 115. The seed layer may have a single-layer structure or a multilayer structure. When the conductor pattern 112 is deposited by electroplating, a seed layer is further provided between the conductor pattern 112 and its substrate. The conductor layer may further include an adhesion layer between the seed layer and its substrate. The thickness of the conductor layer is preferably 1 μm or less.

[0071] <1.2> Manufacturing method of a wiring board The above-mentioned wiring board 10 can be manufactured, for example, by the following method.

[0072] Figures 4 to 13 are schematic cross-sectional views illustrating a method for manufacturing a wiring board according to the first embodiment of the present invention.

[0073] First, a multilayer wiring structure is obtained with reference to Figure 1. The insulating layer 111 is, for example, an insulating resin layer. The insulating layer 111 may be made of a photosensitive material or a non-photosensitive material. The conductor pattern 112 is made of a metallic material such as Al, Cu, and Ni. Here, as an example, considering electrical properties, ease of manufacture, and cost, a conductor pattern 112 made of copper is formed by electroplating.

[0074] Next, an insulating layer 114, as shown in Figure 4, is provided on the upper surface of the multilayer wiring structure. For example, the material of the insulating layer 114 can be the same as that exemplified for the insulating layer 111. The material of the insulating layer 114 may be the same as or different from that of the insulating layer 111. Solder resist may also be used for the insulating layer 114.

[0075] As described above, through holes are provided in the insulating layer 114. Hereinafter, these through holes will be referred to as the first through holes. The lower surface of the insulating layer 114 will be referred to as the first main surface, and its back surface, i.e., the upper surface of the insulating layer 114, will be referred to as the second main surface. Each of the first through holes extends from the first main surface to the second main surface. In the laminated structure including the insulating layer 114 and the uppermost conductor pattern 112, the conductor pattern 112 is provided on the first main surface and closes the openings of the first through holes on the first main surface side.

[0076] When a photosensitive material is used as the material for the insulating layer 114, the first through-holes are formed by photolithography. When a non-photosensitive material is used as the material for the insulating layer 114, the first through-holes are formed by laser beam irradiation using, for example, an excimer laser, a carbon dioxide laser, or an ultraviolet (UV) laser.

[0077] Next, as shown in Figure 5, a conductor layer 117 is formed to cover the upper surface of the insulating layer 114, the side wall of the first through-hole, and the area of ​​the conductor pattern 112 that is exposed at the location of the first through-hole.

[0078] The conductive layer 117 is a conformal layer to the upper surface of the laminated structure, which includes the multilayer wiring structure and the insulating layer 114. The conductive layer 117 may be formed in a solution or in a vacuum. For example, the conductive layer 117 is formed by electroless plating or sputtering.

[0079] When using electroless plating, the conductive layer 117 can be made of a metallic material such as Cu, Pd, Al, Sn, Ni, and Cr. When using sputtering, the conductive layer 117 can be made of a layer made of a metallic material such as Cu, Ni, Al, Ti, Cr, Mo, W, Ta, Au, Ir, Ru, Pd, Pt, AlSi, AlSiCu, AlCu, NiFe, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum-doped Zinc Oxide), ZnO, PZT (Lead Zirconate Titanate), TiN, Cu3N4, Cu alloy, or a combination of two or more of these. Here, as an example, considering electrical properties, ease of manufacture, and cost, a copper layer with a thickness of 300 nm will be formed as the conductive layer 117 by electroless plating.

[0080] Prior to forming the conductive layer 117, a desmear treatment may be performed to remove resin residue from the conductive pattern 112. The desmear treatment may be performed in a permanganate solution or in a vacuum.

[0081] Next, as shown in Figure 6, a resist layer 121 having second through-holes that communicate with the first through-holes is provided on the second main surface. That is, a resist layer 121 having through-holes at the positions of the through-holes of the insulating layer 114 is provided on the conductor layer 117. The resist layer 121 can be obtained, for example, by coating the conductor layer 117 with a liquid resist and providing second through-holes in the coating film. Alternatively, the resist layer 121 can be obtained by placing a dry film on the conductor layer 117 and providing second through-holes in it.

[0082] Next, a metallic material is deposited in the first and second through-holes by a plating method, filling the first through-hole and forming a junction electrode 115 that protrudes columnarly from the second main surface, as shown in Figure 7. The junction electrode 115 can be formed by an electroplating method using the conductive layer 117 as the power supply layer. Here, as an example, considering electrical characteristics, ease of manufacture, and cost, an electroplated copper layer is formed as the junction electrode 115.

[0083] Next, as shown in Figure 8, the resist layer 121 is removed. The resist layer 121 can be removed, for example, by immersion in a stripping agent or by dry etching.

[0084] Next, a resist layer 122, as shown in Figure 9, is provided. The resist layer 122 partially covers the bonding electrode 115. Specifically, the resist layer 122 covers the side surface of the bonding electrode 115 and a portion of the upper surface of the bonding electrode 115. The resist layer 122 has a third through-hole at the position of the upper surface of the bonding electrode 115. The lower opening of the third through-hole is located inside the contour of the upper surface of the bonding electrode 115 and spaced apart from the contour. The diameter R2 of the recess, as described with reference to Figure 3, corresponds to the diameter of the third through-hole. The resist layer 122 can be obtained, for example, by the method described above for the resist layer 121.

[0085] In this case, the resist layer 122 further covers the exposed portion of the conductor layer 117. However, the resist layer 122 does not necessarily have to cover the exposed portion of the conductor layer 117.

[0086] Next, as shown in Figure 10, a portion of the metal material is removed from each of the upper surfaces of the bonding electrodes 115, creating a first region with a recess and a second region surrounding the first region on each of these upper surfaces. Here, a portion of the metal material is removed at the location of the first region. For example, the portion of the bonding electrode 115 exposed at the location of the third through hole is removed by dry etching to form a recess on the upper surface of the bonding electrode. The depth D of the recess, as explained with reference to Figure 3, can be adjusted by the etching time.

[0087] If the upper surface of the junction electrode 115 is made of copper, for example, a mixture of sulfuric acid and hydrogen peroxide, or sodium persulfate can be used as the etching agent. If the upper surface of the junction electrode 115 is made of nickel, a known etching agent used for etching nickel can be used as the etching agent.

[0088] The recess can also be formed by wet etching. In the case of wet etching, the diameter R2 of the recess is generally larger than the diameter below the third through hole.

[0089] The recesses can also be formed by physical means. For example, a portion of the metal material may be removed from the upper surface of the bonding electrode 115 by spraying an abrasive, thereby forming recesses on each of those upper surfaces.

[0090] After forming the recess, the exposed surface of the bonding electrode 115 may be subjected to surface treatment. For example, the surface treatment can be performed by electroplating or electroless plating. Electroplating can form a surface treatment layer consisting of, for example, Sn, solder, Au, Ni, or Pd. Electroless plating can form a surface treatment layer consisting of, for example, Sn, Au, Ni, or Pd.

[0091] Next, as shown in Figure 11, bonding material layers 116 are formed on the upper surface of the bonding electrode 115, each protruding outward from the recess at the location of the recess. The bonding material layers 116 can be formed in various ways.

[0092] For example, solder paste is supplied onto the resist layer 122, and this is spread over the entire upper surface of the resist layer 122 with a squeegee to fill the recess and third through-hole provided on the upper surface of the bonding electrode 115 with the solder paste, while removing any excess solder paste remaining on the upper surface of the resist layer 122.

[0093] Alternatively, solder is deposited on the recess provided on the upper surface of the junction electrode 115 by an electroplating method using the conductive layer 117 as a power supply layer, thereby forming a solder layer that fills the recess and the third through hole.

[0094] Alternatively, flux is supplied onto the resist layer 122 and spread over the entire upper surface of the resist layer 122 with a squeegee to fill the recesses on the upper surface of the bonding electrode 115 with flux, while removing any excess flux remaining on the upper surface of the resist layer 122. Subsequently, solder balls are placed in the third through-hole and adhered to the bonding electrode 115 via the flux. In this method, since the amount of solder is determined by the volume of the solder balls, it is possible to form a bonding material layer 116 with little variation in the amount of solder.

[0095] Next, the resist layer 122 is removed, as shown in Figure 12. The resist layer 122 can be removed, for example, by the same method as described above for the resist layer 121.

[0096] Next, reflow soldering is performed. When the solder melts during reflow soldering, the upper surface of the bonding material layer 116 takes on a dome shape due to surface tension, as shown in Figure 13. Also, surfaces made of copper or nickel are not easily wetted by molten solder. Therefore, if the second region, that is, the region surrounding the recess on the upper surface of the bonding electrode 115, is made of copper or nickel, the molten solder is unlikely to spread to the second region and will remain in the first region where the recess is provided.

[0097] Furthermore, to prevent excessive spreading of molten solder, the sides of the portion of the bonding electrode 115 that protrudes from the insulating layer may be covered with an organic material layer prior to reflow. The organic material layer is, for example, an OSP (Organic Solderability Preservative) film. The organic material layer may be left on the board after reflow without being removed. In this case, the wiring board 10 obtained will include an organic material layer covering the sides of the portion of the bonding electrode 115 that protrudes from the insulating layer.

[0098] The reflow temperature is set appropriately according to the composition of the bonding material layer 116. In one embodiment, solder with a composition represented by Sn-3.0Ag-0.5Cu was used for the bonding material layer 116, and the reflow temperature was set to 260°C. As a result of this reflow, the upper surface of the bonding material layer 116 became dome-shaped, as shown in Figure 13.

[0099] Subsequently, the exposed portion of the conductor layer 117 is removed. The exposed portion of the conductor layer 117 is removed, for example, by etching. In this case, for example, an etching agent is used that allows the conductor layer 117 to be etched with a high selectivity ratio relative to the bonding material layer 116.

[0100] Furthermore, an insulating layer 113, as described with reference to Figure 1, is provided on the underside of the multilayer wiring structure. The insulating layer 113 may also be provided on the underside of the multilayer wiring structure at another stage. In this way, the wiring board 10 described with reference to Figures 1 to 3 is obtained.

[0101] <1.3> Packaged devices Figure 14 is a schematic cross-sectional view showing a packaged device according to one embodiment of the present invention.

[0102] The packaged device 1 shown in Figure 14 includes the aforementioned wiring board 10, functional device 20, bonding material layer 32, and sealing resin layer 40.

[0103] As described above, the functional device 20 is a device that operates when at least one of power and / or an electrical signal is supplied, a device that outputs at least one of power and / or an electrical signal in response to an external stimulus, or a device that operates when at least one of power and / or an electrical signal is supplied and also outputs at least one of power and / or an electrical signal in response to an external stimulus. The functional device 20 is in the form of a chip, such as a semiconductor chip or a chip on which circuits and elements are formed on a substrate made of a material other than a semiconductor, such as a glass substrate. Here, as an example, the functional device 20 is assumed to be a semiconductor chip.

[0104] The functional device 20 includes a functional device body 21 and a plurality of bonding electrodes 22. The functional device 20 is bonded to the wiring board 10 by flip-chip bonding.

[0105] The functional device body 21 is flat. The functional device body 21 is the part of the functional device 20 other than the bonding electrode 22. The functional device body 21 faces the upper surface of the wiring board 10 with a gap between them.

[0106] The bonding electrode 22 protrudes in a columnar shape from the functional device body 21. Specifically, the bonding electrode 22 protrudes in a columnar shape from the surface of the functional device body 21 facing the wiring board 10. The bonding electrode 22 is bonded to the bonding electrode 115 of the wiring board 10 via the bonding material layer 31, thereby electrically connecting the functional device 20 to the wiring board 10. Here, the portion of the bonding electrode 22 that protrudes from the functional device body 21 has a substantially cylindrical shape with a diameter approximately equal to that of the bonding electrode 115, and each surface facing the wiring board 10 is flat. These flat surfaces face the upper surface of the bonding electrode 115 with the bonding material layer 31 in between.

[0107] The bonding material layer 31 is made of, for example, solder. Before being bonded to the wiring board 10, the functional device 20 includes a bonding material layer, made of, for example, solder, on the flat surface of the bonding electrode 22. The metal materials constituting these bonding material layers and the metal materials constituting the bonding material layer 116 of the wiring board 10 melt and mix together when the functional device 20 is bonded to the wiring board 10. The bonding material layer 31 is the cured product of this mixture.

[0108] The bonding layer 32 is a metal bump provided on the portion of the conductor pattern 112 that is exposed at the location of the through-holes in the insulating layer 113. The bonding layer 32 is made of, for example, solder.

[0109] The sealing resin layer 40 includes a portion interposed between the functional device 20 and the wiring board 10. The sealing resin layer 40 fixes the functional device 20 to the wiring board 10. The sealing resin layer 40 consists of an insulating resin layer. The insulating resin layer is, in one example, obtained from an underfill material.

[0110] <1.4> Effect According to the technology described above, it is possible to achieve excellent connection reliability in the connection between the functional device 20 and the wiring board 10. This will be explained below.

[0111] Figure 15 is a schematic cross-sectional view showing one step in the manufacturing method of a packaged device according to a comparative example. Figure 16 is a schematic cross-sectional view showing an example of a structure obtained by the step in Figure 15.

[0112] The method relating to the comparative example shown in Figures 15 and 16 is the same as the method described with reference to Figures 1 to 14, except that a wiring board 10X is used instead of the wiring board 10. That is, in the wiring board 10X used in the method relating to the comparative example, the upper surface of the bonding electrode 115 is flat, and the bonding material layer 116 spreads over the entire upper surface of the bonding electrode 115. Except for this point, the wiring board 10X is the same as the wiring board 10 described above.

[0113] In the wiring board 10X of Figure 15, as described above, the upper surface of the bonding electrode 115 is flat, and the bonding material layer 116 extends across the entire upper surface of the bonding electrode 115. Similarly, in the functional device 20 of Figure 15, the lower surface of the bonding electrode 22 is flat, and the bonding material layer 23 extends across the entire lower surface of the bonding electrode 115.

[0114] When such a wiring board 10X and a functional device 20 are joined together, for example, in positions where the height of the protruding parts of the joining electrodes 22 and 115 is large due to manufacturing variations, or in positions where the distance from the functional device 20 to the insulating layer 114 is short due to warping of the wiring board 10X, molten metal material, which is the joining material, will ooze out from between the joining electrode 22 and the joining electrode 115, as shown in Figure 16.

[0115] If the distance between adjacent bonding electrodes 115 is short, molten material protruding from between a bonding electrode 22 and a bonding electrode 115 may connect with molten material protruding from between an adjacent bonding electrode 22 and a bonding electrode 115, and as a result, adjacent bonding material layers 31 may connect. Alternatively, molten material protruding from between a bonding electrode 22 and a bonding electrode 115 may connect with at least one of the adjacent bonding electrodes 22 and 115, and as a result, a bonding material layer 31 interposed between a bonding electrode 22 and a bonding electrode 115 may connect with at least one of the adjacent bonding electrodes 22 and 115. Furthermore, even if such a situation does not occur, the distance between adjacent bonding material layers 31 will be shorter than the distance between bonding electrodes 115. As a result, a short circuit between bonding electrodes 115 via the bonding material layer 31 may occur.

[0116] Figure 17 is a schematic cross-sectional view showing one step in a method for manufacturing a packaged device according to one embodiment of the present invention. Figure 18 is a schematic cross-sectional view showing an example of a structure obtained by the step in Figure 17.

[0117] In the wiring board 10 used in the method described with reference to Figures 1 to 14, as shown in Figure 17, the upper surface of the bonding electrode 115 includes a first region with a recess and a second region surrounding the first region. The bonding material layer 116 is provided only at the location of the recess.

[0118] In other words, in the wiring board 10, the portion of the bonding material layer 116 located outside the recess has a smaller volume compared to the bonding material layer 116 in the wiring board 10. Also, before bonding, no bonding material is present in the second region of the wiring board 10. Therefore, even in positions where the height of the protruding parts of the bonding electrodes 22 and 115 is large due to manufacturing variations, or in positions where the distance from the functional device 20 to the insulating layer 114 is short due to warping of the wiring board 10X, the molten bonding material does not protrude from between the bonding electrodes 22 and 115 when bonding the wiring board 10 and the functional device 20. Furthermore, even if the molten bonding material does protrude from between the bonding electrodes 22 and 115, the amount of protrusion is small. Consequently, in the above-described packaged device 1, as shown in Figure 18, the bonding material layer 31 does not protrude from between the bonding electrodes 22 and 115, or if it does, the amount of protrusion is small.

[0119] Furthermore, in the wiring board 10, each of the bonding material layers protrudes outward from the recess provided on the upper surface of the bonding electrode 115. Therefore, even in positions where the height of the protrusions of the bonding electrodes 22 and 115 is small due to manufacturing variations, or in positions where the distance from the functional device 20 to the insulating layer 114 is long due to warping of the wiring board 10X, the bonding material layer 23 and the bonding material layer 116 can contact each other. Consequently, the bonding electrodes 22 and 115 can be reliably bonded even in these positions.

[0120] Furthermore, when the molten bonding material moves on the bonding electrode 115 during reflow, and for example, if a portion of it reaches the side surface of the bonding electrode 115, the height of the bonding material layer 116 decreases. In this case, at positions where the height of the protruding parts of the bonding electrodes 22 and 115 is small, or at positions where the distance from the functional device 20 to the insulating layer 114 is long, it may not be possible to bring the bonding electrodes 22 and 115 into contact with each other, making it impossible to bond them together.

[0121] As described above, the wiring board 10 has a recess on the upper surface of the bonding electrode 115, and the bonding material layer 116 is located in the recess. Therefore, the position of the bonding material layer 116 remains almost constant before and after the reflow process, as explained with reference to Figure 13. Connection failures caused by a decrease in the height of the bonding material layer 116 are unlikely to occur.

[0122] Therefore, according to the technology described with reference to Figures 1 to 14, 17 and 18, it is possible to achieve excellent connection reliability in the connection between the functional device 20 and the wiring board 10.

[0123] <1.5> Variation The wiring board 10 described above can be modified in various ways.

[0124] Figure 19 is an enlarged cross-sectional view showing a portion of the wiring board according to the first modified example. Figure 20 is an enlarged cross-sectional view showing a portion of the wiring board according to the second modified example. Figure 21 is an enlarged cross-sectional view showing a portion of the wiring board according to the third modified example.

[0125] The wiring board 10A shown in Figure 19 is the same as the wiring board 10 described above, except that it employs the following configuration. Specifically, in the wiring board 10A, the outer edge of the second region is higher than the inner edge. Here, the upper surface of the junction electrode 115 is concave, and the approximate center of this concave surface is further concave.

[0126] The wiring board 10B shown in Figure 20 is the same as the wiring board 10 described above, except that it employs the following configuration. Specifically, in the wiring board 10B, the inner edge of the second region is higher than the outer edge. Here, the upper surface of the bonding electrode 115 is convex, and the approximate center of this convex surface is further concave.

[0127] By appropriately changing various conditions in the electroplating method used to form the bonding electrode 115, such as the current density and material, it is possible to obtain not only a structure with a flat top surface, as shown in Figure 7, but also a structure with a concave top surface or a structure with a convex top surface. When the outer edge of the second region is higher than the inner edge of the second region, as shown in the wiring board 10A in Figure 19, the molten bonding material is less likely to drip onto the side of the bonding electrode 115 during reflow. Also, when the inner edge of the second region is higher than the outer edge of the second region, as shown in the wiring board 10B in Figure 20, the molten bonding material is less likely to spill out between the bonding electrode 22 and the bonding electrode 115 during bonding.

[0128] The wiring board 10C shown in Figure 21 is the same as the wiring board 10 described above, except that it employs the following configuration. Specifically, in the wiring board 10C, the bonding material layer 116 includes a first portion 116A provided on the first region and a second portion 116B provided on the second region.

[0129] The first portion 116A has the same shape and dimensions as the bonding layer 116 described with reference to Figures 2 and 3. The second portion 116B is a much thinner layer than the first portion 116A. The thickness of the second portion 116B is, for example, 1% or less of the height of the portion of the first portion 116A that protrudes from the recess. For example, the thickness of the second portion 116B is 500 nm or less.

[0130] During reflow soldering, the molten bonding material initially spreads across the entire upper surface of the bonding electrode 115. Subsequently, most of the molten material that moves onto the second region returns to the first region due to surface tension. A portion of the molten material that moves onto the second region may remain on the second region without returning to the first region. The structure shown in Figure 21 can occur, for example, under such circumstances. The structure described above for the bonding material layer 116 of the wiring board 10C can also occur in wiring boards 10A and 10B.

[0131] <2> Second Embodiment <2.1> Functional Devices Figure 22 is an enlarged cross-sectional view showing a portion of a functional device according to a second embodiment of the present invention.

[0132] The functional device 20A shown in Figure 22 is the same as the functional device 20 described with reference to Figure 15, etc., except for the following points. That is, in the functional device 20A, each upper surface of the bonding electrode 22, the surface facing downward in Figure 22, includes a first region with a recess and a second region surrounding the first region. Each of the bonding material layers 23 protrudes outward from the recess at the location of the recess provided in the bonding electrode 22.

[0133] As described above, the functional device 20A employs the same structure for the bonding electrode 22 and bonding material layer 23 as for the bonding electrode 115 and bonding material layer 116 of the wiring board 10, respectively. Such a structure can be obtained, for example, by the same method as described above for the bonding electrode 115 and bonding material layer 116 of the wiring board 10.

[0134] The dimensions of the bonding electrode 22, its recess, and the bonding material layer 23, and the relationship between these dimensions, can be within the ranges described above for the bonding electrode 115, its recess, and the bonding material layer 116, respectively. Furthermore, the shape and arrangement of the bonding electrode 22, its recess, and the bonding material layer 23 can also be appropriately selected as described above for the bonding electrode 115, its recess, and the bonding material layer 116, respectively. Moreover, the bonding electrode 22 and the bonding material layer 23 can be modified in the same way as described for the bonding electrode 115 and the bonding material layer 116 with reference to Figures 19 to 21, respectively.

[0135] <2.2> Packaged Devices Figure 23 is a cross-sectional view showing an example of the structure that a packaged device containing the functional device shown in Figure 22 may have.

[0136] The structure shown in Figure 23 can be obtained in the same manner as described with reference to Figures 17 and 18, except that the wiring board 10X described with reference to Figure 15 and the functional device 20A described with reference to Figure 22 are used instead of the wiring board 10 and the functional device 20, respectively. The packaged device having the structure shown in Figure 23 is the same as the packaged device 1 described with reference to Figure 14, except that the surface of the bonding electrode 115 facing the bonding electrode 22 is flat, and the above-mentioned recess is provided on the surface of the bonding electrode 22 facing the bonding electrode 115.

[0137] Even when this configuration is adopted, the same effects as those described in the first embodiment can be obtained.

[0138] Figure 24 is a cross-sectional view showing another example of the structure that a packaged device containing the functional device shown in Figure 22 may have.

[0139] The structure shown in Figure 24 can be obtained in the same manner as described with reference to Figures 17 and 18, except that the functional device 20A described with reference to Figure 22 is used instead of the functional device 20. The packaged device having the structure shown in Figure 24 is the same as the packaged device 1 described with reference to Figure 14, except that the above-mentioned recess is provided on the surface of the junction electrode 22 facing the junction electrode 115. In the structure of Figure 24, the first and second regions described above on the upper surface of the junction electrode 22 may be referred to as the third and fourth regions, respectively.

[0140] Even when this configuration is adopted, the same effects as those described in the first embodiment can be obtained. Furthermore, when this configuration is adopted, the overflow of molten material from the bonding agent is even less likely to occur.

[0141] <3> Other variations Figure 25 is a plan view showing an enlarged portion of the wiring board relating to the fourth modified example. Figure 26 is a plan view showing an enlarged portion of the wiring board in Figure 25.

[0142] The wiring board 10D shown in Figure 25 is the same as the wiring board 10D except that it employs the following configuration. Specifically, in the wiring board 10D shown in Figure 25, among the bonding electrodes 115, those located on the periphery surrounding the central part of the insulating layer 114 have a greater distance from the center of the upper surface of the bonding electrode 115 to the center of the recess compared to those located in the central part. Here, as shown in Figures 25 and 26, the position of the center of the recess of the bonding electrode 115 located on the periphery is shifted away from the central part of the insulating layer 114 relative to the position of the center of the upper surface of the bonding electrode 115. Furthermore, as shown in Figure 25, the magnitude of the shift in the position of the center of the recess relative to the center of the upper surface of the bonding electrode 115 increases continuously with increasing distance from the central part of the insulating layer 114.

[0143] When joining the wiring board 10 and the functional device 20, the heating required for this joining process may cause the wiring board 10 to warp. For example, the wiring board 10 may warp so that the surface facing the functional device 20 becomes convex. On the other hand, the functional device 20 may not warp, or it may not warp as much as the wiring board 10. Therefore, if the wiring board 10 warps, even if the joining electrode 115 located in the center of the insulating layer 114 and the corresponding joining electrode 22 are joined in the correct relative positions, a misalignment may occur between the joining electrode 115 located at the periphery of the insulating layer 114 and the corresponding joining electrode 22. The magnitude of this misalignment increases continuously with increasing distance from the center of the insulating layer 114. Consequently, it may become impossible to bring the joining material layer 116 and the joining material layer 23 into contact at the periphery, making it impossible to join the joining electrode 115 and the joining electrode 22.

[0144] When using the wiring board 10D described with reference to Figures 25 and 26, even if warping occurs, the bonding material layer 116 and the bonding material layer 23 can be brought into contact at the peripheral edge. Therefore, the bonding material layer 116 and the bonding material layer 23 can be reliably bonded even at the peripheral edge.

[0145] In the wiring board 10D, the magnitude of the displacement of the center of the recess relative to the center of the upper surface of the bonding electrode 115 increases continuously with increasing distance from the center of the insulating layer 114. The magnitude of the displacement of the center of the recess relative to the center of the upper surface of the bonding electrode 115 may also increase in steps with increasing distance from the center of the insulating layer 114.

[0146] The structure described here can be applied not only to the wiring board 10, but also to other wiring boards such as 10A, 10B, and 10C.

[0147] Furthermore, the structure described here is also applicable to functional devices such as the functional device 20A. Specifically, among the bonding electrodes 22, those located on the periphery surrounding the central part of the functional device body 21 may have a larger distance from the center of the upper surface of the bonding electrode 22 to the center of the recess compared to those located in the central part. In this case, the center of the recess of the bonding electrode 22 located on the periphery is shifted relative to the center of the upper surface of the bonding electrode 22 in a direction closer to the central part of the functional device body 21. The magnitude of the shift in the position of the center of the recess relative to the center of the upper surface of the bonding electrode 22 is continuously reduced in proportion to the increasing distance from the central part of the functional device body 21. Alternatively, the magnitude of the shift in the position of the center of the recess relative to the center of the upper surface of the bonding electrode 22 is gradually reduced in proportion to the increasing distance from the central part of the functional device body 21. Even when this configuration is adopted, the bonding material layer 116 and the bonding material layer 23 can be reliably bonded.

[0148] Figure 27 is a schematic cross-sectional view showing one step in the manufacturing method of a wiring board according to the fifth modified example. Figure 28 is a schematic cross-sectional view showing another step in the manufacturing method of a wiring board according to the fifth modified example.

[0149] In the method described with reference to Figures 9 and 10, a structure having a recess in the first region is obtained by removing a portion of the metal material from the upper surface of the bonding electrode 115 at the location of the first region. In the method described with reference to Figure 19, first, the bonding electrode 115 is formed so that its upper surface is concave, and then a structure having a recess in the first region is obtained by removing a portion of the metal material from the upper surface of the bonding electrode 115 at the location of the second region. Unlike these methods, the fifth modified example obtains a structure having a recess in the first region.

[0150] First, using the same method as described with reference to Figures 4 to 7, the structure of Figure 27 is obtained with the resist layer 123 omitted. Note that the resist layer 121 is the first resist layer, and the through holes in the insulating layer 114 and the resist layer 121 are the first and second through holes, respectively. Also, the first conductor portion 115A in Figure 27 corresponds to the junction electrode 115 in Figure 7.

[0151] Next, a region along the edge of each upper surface of the first conductor portion 115A is exposed, and a resist layer 123 is provided to cover the region enclosed by this region. The resist layer 123 is a second resist layer. Here, the resist layer 123 further covers the conductor layer 117. The resist layer 123 can be formed, for example, by the same method as described above for the resist layers 121 and 122.

[0152] Next, a metal material is further deposited on the exposed area by a plating method to form a second conductor portion 115B on top of the first conductor portion 115A. This results in a plurality of junction electrodes 115, each containing the first conductor portion 115A and the second conductor portion 115B, with each upper surface containing a first region with a recess and a second region surrounding the first region.

[0153] The deposition of the metallic material can be carried out in the same manner as described with reference to Figure 7. The metallic material deposited here may be the same as or different from the metallic material constituting the first conductor portion 115A.

[0154] Next, the resist layer 123 is removed. The resist layer 123 can be removed in the same manner as described above for the resist layer 121.

[0155] Next, the resist layer 122 is provided in the same manner as described with reference to Figure 9. The resist layer 122 is provided such that, for example, when viewed from the thickness direction, the contour of the lower opening of each through hole coincides with the contour of the opening of the recess provided on the upper surface of the bonding electrode 115, or surrounds the contour of the opening of this recess.

[0156] Subsequently, the processes described with reference to Figures 11 to 13 are carried out sequentially. This results in a wiring board having a structure substantially similar to the wiring board 10 described with reference to Figures 1 to 3.

[0157] A wiring board obtained by this method will also produce the same effects as described above when connected to a functional device 20 or 20A.

[0158] Furthermore, the method described here can also be applied to the manufacturing of the functional device 20A, as described with reference to Figure 22. The functional device obtained in this way will also produce the same effects as described above when joined to the wiring boards 10, 10A, 10B, 10C, or 10X. [Explanation of symbols]

[0159] 1...Packaging device, 10...Wiring board, 10A...Wiring board, 10B...Wiring board, 10C...Wiring board, 10D...Wiring board, 10X...Wiring board, 11...Layer, 20...Functional device, 20A...Functional device, 21...Functional device body, 22...Bonding electrode, 23...Bonding material layer, 31...Bonding material layer, 32...Bonding material layer, 40...Sealing resin layer, 111...Insulating layer, 112...Conductor pattern, 113...Insulating layer, 114...Insulating layer, 115...Bonding electrode, 115A...First conductor part, 115B...Second conductor part, 116...Bonding material layer, 116A...First part, 116B...Second part, 117...Conductor layer, 121...Resist layer, 122...Resist layer, 123...Resist layer.

Claims

1. An insulating layer having a first main surface and a second main surface which is its back surface, and having a plurality of through holes extending from the first main surface to the second main surface, A conductor pattern provided on the first main surface, which closes the openings on the first main surface side of the plurality of through holes, Each of the aforementioned multiple through holes is embedded in a plurality of bonding electrodes that protrude columnarly from the second main surface, and the upper surface of each of these bonding electrodes includes a first region with a recess and a second region surrounding the first region. Equipped with, The second region is a wiring board in which the outer edge is higher than the inner edge.

2. An insulating layer having a first main surface and a second main surface which is its back surface, and having a plurality of through holes extending from the first main surface to the second main surface, A conductor pattern provided on the first main surface, which closes the openings on the first main surface side of the plurality of through holes, Each of the aforementioned multiple through holes is embedded in a plurality of bonding electrodes that protrude columnarly from the second main surface, and the upper surface of each of these bonding electrodes includes a first region with a recess and a second region surrounding the first region. Equipped with, A wiring board in which, among the plurality of bonding electrodes, those located at the peripheral edge surrounding the central part of the insulating layer have a larger distance from the center of the recess to the center of the upper surface compared to those located at the central part.

3. The wiring board according to claim 2, wherein, of the plurality of bonding electrodes, those located at the periphery, have the position of the center of the recess shifted away from the central part with respect to the position of the center of the upper surface.

4. The wiring board according to any one of claims 1 to 3, further comprising a plurality of bonding material layers provided on the upper surfaces of the plurality of bonding electrodes, wherein each of the plurality of bonding material layers protrudes outward from the recess at the position of the recess.

5. An insulating layer having a first main surface and a second main surface which is its back surface, and having a plurality of through holes extending from the first main surface to the second main surface, A conductor pattern provided on the first main surface, which closes the openings on the first main surface side of the plurality of through holes, Each of the aforementioned multiple through holes is embedded, and a plurality of bonding electrodes protrudes columnarly from the second main surface, the upper surface of each of the bonding electrodes includes a first region with a recess and a second region surrounding the first region, A plurality of bonding material layers are provided on the upper surfaces of the plurality of bonding electrodes, respectively. Equipped with, Each of the plurality of bonding material layers protrudes outward from the recess at the location of the recess, One or more of the plurality of bonding material layers include a first portion provided on the first region and a second portion provided on the second region. The second portion is a wiring board having a thickness of 1% or less of the height of the portion of the first portion that protrudes from the recess.

6. The wiring board according to claim 4 or 5, wherein each of the plurality of bonding material layers is made of solder, and the second region is made of copper or nickel.

7. A wiring board according to any one of claims 1 to 3, A functional device comprising a functional device body and a plurality of bonding electrodes protruding from the functional device body, wherein each of the plurality of bonding electrodes of the functional device is interposed between the plurality of bonding electrodes of the wiring board and the functional device body, A plurality of bonding material layers are interposed between the plurality of bonding electrodes of the wiring board and the plurality of bonding electrodes of the functional device, respectively. A packaged device equipped with the following features.

8. A wiring board according to any one of claims 4 to 6, A functional device comprising a functional device body and a plurality of bonding electrodes protruding from the functional device body, wherein each of the plurality of bonding electrodes of the functional device comprises a functional device interposed between the plurality of bonding electrodes of the wiring board and the functional device body. The plurality of bonding material layers are interposed between the plurality of bonding electrodes of the wiring board and the plurality of bonding electrodes of the functional device in a packaged device.

9. The packaged device according to claim 7 or 8, wherein the plurality of bonding electrodes of the functional device each have an upper surface that includes a third region having a recess and a fourth region surrounding the third region.

10. A functional device is prepared comprising a functional device body, a plurality of bonding electrodes protruding from the functional device body, and a plurality of bonding material layers provided on the upper surfaces of each of the plurality of bonding electrodes. The wiring board described in any one of claims 1 to 3, On the upper surface of the plurality of bonding electrodes of the wiring board, a plurality of bonding material layers are provided such that each of the plurality of bonding material layers protrudes outward from the recess at the position of the recess. The plurality of bonding material layers of the functional device and the plurality of bonding material layers of the wiring board are brought into contact with each other, and heat is applied to them in this state to bond the plurality of bonding electrodes of the functional device and the plurality of bonding electrodes of the wiring board to each other. A method for manufacturing a packaged device that includes [the specified component].

11. A functional device is prepared comprising a functional device body, a plurality of bonding electrodes protruding from the functional device body, and a plurality of bonding material layers provided on the upper surfaces of each of the plurality of bonding electrodes. The wiring board described in any one of claims 4 to 6, The plurality of bonding material layers of the functional device and the plurality of bonding material layers of the wiring board are brought into contact with each other, and heat is applied to them in this state to bond the plurality of bonding electrodes of the functional device and the plurality of bonding electrodes of the wiring board to each other. A method for manufacturing a packaged device that includes [the specified component].

12. The main functional device and A plurality of bonding electrodes protruding from the functional device body, each of which has an upper surface comprising a plurality of bonding electrodes including a first region having a recess and a second region surrounding the first region, The second region is a functional device in which the outer edge is positioned higher than the inner edge.

13. The main functional device and A plurality of bonding electrodes protruding from the functional device body, each of which has an upper surface comprising a plurality of bonding electrodes including a first region having a recess and a second region surrounding the first region, A functional device in which, among the plurality of bonding electrodes, those located on the peripheral edge surrounding the central part of the functional device body have a larger distance from the center of the recess to the center of the upper surface compared to those located on the central part.

14. The functional device according to claim 13, wherein, among the plurality of bonding electrodes, those located at the periphery have the position of the center of the recess shifted away from the central part with respect to the position of the center of the upper surface.

15. The functional device according to any one of claims 12 to 14, further comprising a plurality of bonding material layers provided on the upper surfaces of the plurality of bonding electrodes, wherein each of the plurality of bonding material layers protrudes outward from the recess at the position of the recess.

16. The main functional device and A plurality of bonding electrodes protruding from the functional device body, each of which has an upper surface including a first region with a recess and a second region surrounding the first region, A plurality of bonding material layers are provided on the upper surfaces of the plurality of bonding electrodes, respectively. Equipped with, Each of the plurality of bonding material layers protrudes outward from the recess at the location of the recess, One or more of the plurality of bonding material layers include a first portion provided on the first region and a second portion provided on the second region. The second portion is a functional device having a thickness of 1% or less of the height of the portion of the first portion that protrudes from the recess.

17. A wiring board comprising: an insulating layer having a first main surface and a second main surface which is its back surface, each having a plurality of through holes extending from the first main surface to the second main surface; a conductor pattern provided on the first main surface that closes the openings of the plurality of through holes on the first main surface side; and a plurality of bonding electrodes that fill each of the plurality of through holes and protrude columnarly from the second main surface; A functional device according to any one of claims 12 to 14, wherein each of the plurality of bonding electrodes of the functional device is interposed between the plurality of bonding electrodes of the wiring board and the functional device, A plurality of bonding material layers are interposed between the plurality of bonding electrodes of the wiring board and the plurality of bonding electrodes of the functional device, respectively. A packaged device equipped with the following features.

18. A wiring board comprising: an insulating layer having a first main surface and a second main surface which is its back surface, each having a plurality of through holes extending from the first main surface to the second main surface; a conductor pattern provided on the first main surface that closes the openings of the plurality of through holes on the first main surface side; and a plurality of bonding electrodes that fill each of the plurality of through holes and protrude columnarly from the second main surface; A functional device according to claim 15 or 16, wherein each of the plurality of bonding electrodes of the functional device is interposed between the plurality of bonding electrodes of the wiring board and the functional device. Equipped with, The plurality of bonding material layers are interposed between the plurality of bonding electrodes of the wiring board and the plurality of bonding electrodes of the functional device in a packaged device.

19. A wiring board is prepared comprising: an insulating layer having a first main surface and a second main surface which is its back surface, each having a plurality of through holes extending from the first main surface to the second main surface; a conductor pattern provided on the first main surface that closes the openings of the plurality of through holes on the first main surface side; a plurality of bonding electrodes that fill each of the plurality of through holes and protrude columnarly from the second main surface; and a plurality of bonding material layers provided on the upper surfaces of each of the plurality of bonding electrodes. To prepare a functional device according to any one of claims 12 to 14, On the upper surface of each of the multiple bonding electrodes of the functional device, a plurality of bonding material layers are provided such that each of the plurality of bonding material layers protrudes outward from the recess at the location of the recess. The plurality of bonding material layers of the functional device and the plurality of bonding material layers of the wiring board are brought into contact with each other, and heat is applied to them in this state to bond the plurality of bonding electrodes of the functional device and the plurality of bonding electrodes of the wiring board to each other. A method for manufacturing a packaged device that includes [the specified component].

20. A wiring board is prepared comprising: an insulating layer having a first main surface and a second main surface which is its back surface, each having a plurality of through holes extending from the first main surface to the second main surface; a conductor pattern provided on the first main surface that closes the openings of the plurality of through holes on the first main surface side; a plurality of bonding electrodes that fill each of the plurality of through holes and protrude columnarly from the second main surface; and a plurality of bonding material layers provided on the upper surfaces of each of the plurality of bonding electrodes. To prepare the functional device described in claim 15 or 16, The plurality of bonding material layers of the functional device and the plurality of bonding material layers of the wiring board are brought into contact with each other, and heat is applied to them in this state to bond the plurality of bonding electrodes of the functional device and the plurality of bonding electrodes of the wiring board to each other. A method for manufacturing a packaged device that includes [the specified component].

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