Structure with electrode and packaged device

Abstract

To provide a technique capable of achieving a high connection reliability.SOLUTION: A structure 1 with an electrode is a structure 1 with an electrode including a structure 10 and a plurality of electrodes 11 provided on the structure 10. Each of the plurality of electrodes 11 includes a first main surface S1 in contact with the structure 10 and a second main surface S2 opposite to the first main surface S1, and each of the plurality of electrodes 11 has one or more constricted parts 111 between the first main surface S1 and the second main surface S2 in a first cross section parallel to a height direction thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to electroded structures and packaged devices. [Background technology]

[0002] As semiconductor devices become more highly integrated and multifunctional, the number of terminals, i.e., electrodes, provided on semiconductor chips tends to increase. In response to this trend, a mounting method using a ball grid array (BGA) has been adopted as a method for mounting semiconductor devices on wiring boards, replacing the mounting method using a lead frame. In a mounting method using a BGA, a semiconductor device having a mounting surface with multiple electrodes arranged in a grid pattern is connected to a wiring board using a bonding conductor such as solder. For example, Patent Document 1 discloses an example in which a conductive bump formed by plating and a solder layer covering the conductive bump are used as the bonding conductor. When the bonding conductor is formed by plating, the height of the bonding conductor is less likely to vary. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-140248 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a technique that can achieve high connection reliability. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided an electrode-equipped structure comprising a structure and a plurality of electrodes provided on the structure, wherein each of the plurality of electrodes includes a first main surface in contact with the structure and a second main surface opposite the first main surface, and each of the plurality of electrodes has a first cross section parallel to its height direction that has one or more constrictions between the first main surface and the second main surface.

[0006] According to another aspect of the present invention, there is provided an electrode-equipped structure according to the above aspect, in which, in the first cross section, the area A1 of the circumscribing rectangle having the smallest area among the rectangles circumscribing the contour of the electrode is larger than the area A2 of the electrode.

[0007] According to yet another aspect of the present invention, there is provided an electrode-equipped structure according to the above aspect, wherein the ratio A2 / A1 of the area A2 to the area A1 is in the range of 0.70 to less than 1.0.

[0008] According to yet another aspect of the present invention, there is provided an electrode-equipped structure according to any of the above aspects, wherein, for at least one of the one or more constricted portions, the width CW of the constricted portion in the first cross section is within a range of 0.70 to less than 1.0 times the dimension in the width direction perpendicular to the height direction of each of a first portion P1 of the outline of the first cross section corresponding to the first main surface and a second portion P2 of the outline of the first cross section corresponding to the second main surface.

[0009] According to yet another aspect of the present invention, there is provided an electrode structure according to any of the above aspects, wherein the center-to-center distance between two adjacent electrodes is within the range of 1.5 to 5 times the diameter of the circle having the smallest area among the circles circumscribing the outline of the second main surface.

[0010] According to yet another aspect of the present invention, there is provided an electrode-equipped structure according to any one of the above aspects, wherein the structure is in the form of a plate, a sheet, or a film.

[0011] According to yet another aspect of the present invention, there is provided a packaged device comprising a wiring board, a bonding conductor, and a functional device mounted on the wiring board via the bonding conductor, wherein one of the wiring board and the functional device is an electrode-equipped structure according to any of the above aspects, and at least a portion of the bonding conductor is interposed between the other of the wiring board and the functional device and the plurality of electrodes.

[0012] Here, a "functional device" refers to a device that operates when supplied with at least one of power and an electrical signal, a device that outputs at least one of power and an electrical signal in response to an external stimulus, or a device that operates when supplied with at least one of power and an electrical signal and outputs at least one of power and an electrical signal in response to an external stimulus. The functional device may be 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 a semiconductor, such as a glass substrate. The functional device may include, for example, one or more of a large-scale integrated circuit (LSI), a memory, an imaging element, a light-emitting element, and a MEMS (Micro Electro Mechanical Systems). The MEMS may include, for example, one or more of a pressure sensor, an acceleration sensor, a gyro sensor, a tilt sensor, a microphone, and an acoustic sensor. According to one example, the functional device is a semiconductor chip including an LSI. [Effects of the Invention]

[0013] The present invention provides a technique that can achieve high connection reliability. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view schematically showing an electrode-equipped structure according to one embodiment of the present invention. [Figure 2] 2 is a diagram showing widths W1, W2 and CW of the electrode shown in FIG. 1; [Figure 3] 1 is a schematic diagram illustrating a packaged device according to an embodiment of the present invention; [Figure 4]4 is a cross-sectional view showing a cross section of the packaged device shown in FIG. 3 taken along line IV-IV. [Figure 5] FIG. 3 is a cross-sectional view schematically showing a first conductive layer forming step in a method for manufacturing an electrode-equipped structure according to one embodiment of the present invention. [Figure 6] 4A to 4C are cross-sectional views schematically showing a resist layer forming step in a method for manufacturing an electrode-equipped structure according to one embodiment of the present invention. [Figure 7] FIG. 3 is a cross-sectional view schematically showing a second conductive layer forming step in a method for manufacturing an electrode-equipped structure according to one embodiment of the present invention. [Figure 8] 4A to 4C are cross-sectional views schematically showing a resist layer removal step in a method for manufacturing an electrode-equipped structure according to one embodiment of the present invention. [Figure 9] 3A to 3C are cross-sectional views schematically illustrating a bonding step in a method for manufacturing a packaged device according to an embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view schematically showing a packaged device according to a comparative example. [Figure 11] FIG. 10 is a cross-sectional view schematically showing a packaged device according to another comparative example. [Figure 12] FIG. 10 is a cross-sectional view schematically showing a packaged device according to another comparative example. [Figure 13] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to a comparative example. [Figure 14] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to another comparative example. [Figure 15] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to a modified example. [Figure 16] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to another modified example. [Figure 17] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. [Figure 18] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. [Figure 19] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. [Figure 20] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. [Figure 21] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. [Figure 22] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. [Figure 23] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. [Figure 24] FIG. 10 is a cross-sectional view schematically showing an electrode-equipped structure according to yet another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are more specific embodiments of any of the above aspects. Elements having the same or similar functions are given the same reference numerals, and redundant explanations will be omitted. It should be noted that the drawings are schematic, and the relationship between the dimension in the thickness direction and the dimension in the direction perpendicular to the thickness direction, i.e., the in-plane direction, and the relationship between the dimensions in the thickness direction of multiple layers may differ from the actual ones. Therefore, specific dimensions should be determined with reference to the following explanation. It should also be noted that the dimensional relationship between two or more components may differ between multiple drawings.

[0016] The following embodiments are examples that embody the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the materials, shapes, structures, and arrangements 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.

[0017] In this disclosure, the terms are defined as follows: The term "forward tapered" is used for a structure that does not have a substance, such as an opening, to describe a shape that tapers from the opening toward the back, i.e., a shape that tapers from the surface side toward the base side. The term "forward tapered" is used for a structure that has a substance, such as a first conductive layer, to describe a shape that tapers from the bottom surface toward the top surface, i.e., a shape that tapers from the base side toward the surface side.

[0018] Furthermore, in this disclosure, the expression "AA on BB" is used regardless of the direction of gravity. The state specified by the expression "AA on BB" includes a state in which AA is in contact with BB. The expression "AA on BB" does not exclude the presence of one or more other components between AA and BB.

[0019] <Structure with electrodes> 1 is a cross-sectional view schematically showing an electrode-equipped structure according to one embodiment of the present invention. The electrode-equipped structure is, for example, a wiring substrate or the above-mentioned functional device. The wiring substrate is, for example, a multilayer wiring substrate such as an interposer.

[0020] The electrode-equipped structure 1 shown in FIG. 1 includes a structure 10 and a plurality of electrodes 11 provided on the structure 10. FIG. 1 shows one of the plurality of electrodes 11. Also, in FIG. 1, the cross section of the electrode 11 is a first cross section parallel to its height direction. The first cross section is selected, for example, so that the center of gravity of the first main surface or the center of gravity of the second main surface is located on the first cross section. The first and second main surfaces will be described later. The electrode-equipped structure 1 can be used, for example, for manufacturing a packaged device. The packaged device will also be described later.

[0021] The structure 10 is, for example, a wiring board body or the above-described functional device body. The wiring board body is the portion of the wiring board excluding the electrodes 11. The functional device body is the portion of the above-described functional device excluding the electrodes 11.

[0022] In another example, the structure 10 is a support including glass. In yet another example, the structure 10 is a laminate including a support including glass and a release layer interposed between the electrode 11 and the support. When the structure 10 is the above-described laminate, for example, the electrode 11 can be transferred to a transfer target such as a wiring board or a functional device. The structure 10 is preferably in the form of a plate, a sheet or a film.

[0023] The electrodes 11 are used, for example, to connect the structure 10 to electronic components such as a functional device and a wiring board. The electrodes 11 are arranged, for example, in a grid pattern on the structure 10.

[0024] The electrode 11 is electrically conductive and is made of, for example, copper, tin, nickel, chromium, titanium, gold, or an alloy containing one or more of these.

[0025] The electrode 11 has a columnar shape and protrudes from the surface of the structure 10, as shown in FIG.

[0026] Each of the multiple electrodes 11 includes a first main surface S1 in contact with the structure 10 and a second main surface S2 opposite the first main surface S1. Each of the first main surface S1 and the second main surface S2 is, for example, circular. The diameter of the circle with the smallest area among the circles circumscribing the outline of the first main surface S1 and the diameter of the circle with the smallest area among the circles circumscribing the outline of the second main surface S2 are, for example, not less than 10 μm and less than 500 μm. Each of these diameters is preferably in the range of 10 μm to 200 μm, and more preferably in the range of 10 μm to 100 μm.

[0027] Each of the plurality of electrodes 11 has a first cross section having one or more constricted portions 111 between the first main surface S1 and the second main surface S2.

[0028] The height of the electrode 11 is preferably in the range of 5 μm to 500 μm, and more preferably in the range of 30 μm to 200 μm.

[0029] The cross section of electrode 11, which is perpendicular to the height direction of electrode 11 and includes constricted portion 111 (hereinafter referred to as constricted portion cross section), is circular. However, this shape does not have to be circular.

[0030] The cross-sectional area of ​​the constricted portion is smaller than the areas of the first main surface S1 and the second main surface S2. At least one of the one or more cross-sectional areas of the constricted portion has the smallest area SS1 among the cross-sectional areas of the electrode 11 perpendicular to the height direction.

[0031] The ratio SS1 / SS2 of the area SS1 to the area SS2, which is the smaller of the area of ​​the first main surface S1 and the area of ​​the second main surface S2, is preferably 0.5 or more, more preferably 0.7 or more, and even more preferably 0.9 or more.

[0032] 1 indicates the outline of the circumscribing rectangle having the smallest area among the rectangles circumscribing the outline of electrode 11. As shown in FIG. 1, in the first cross section, the area A1 of this circumscribing rectangle is preferably larger than the area A2 of electrode 11.

[0033] The ratio A2 / A1 of the area A2 to the area A1 is preferably in the range of 0.70 to 0.99, and more preferably in the range of 0.75 to 0.9. If this ratio is too small, the strength of the electrode 11 is likely to be reduced. If this ratio is too large, a short circuit may occur between two adjacent electrodes 11.

[0034] The center-to-center distance between two adjacent electrodes 11 is preferably within a range of 1.5 to 5 times, and more preferably within a range of 2 to 3 times, the diameter of the circle that has the smallest area among the circles circumscribing the outline of the second main surface S2. For example, the center-to-center distance between two adjacent electrodes 11 is within a range of 15 μm to 2500 μm.

[0035] In FIG. 1, the first main surface S1 and the second main surface S2 have the same shape, but these shapes may be different.

[0036] 2 is a diagram showing widths W1, W2, and CW of the electrode 11 shown in FIG. Width W1 is the dimension in the width direction perpendicular to the height direction of a first portion P1 of the outline of the first cross section that corresponds to the first main surface S1. Width W2 is the dimension in the width direction perpendicular to the height direction of a second portion P2 of the outline of the first cross section that corresponds to the second main surface S2. Width CW is the width of the constricted portion 111.

[0037] The width CW is preferably in the range of 0.7 to 0.99 times the widths W1 and W2, and more preferably in the range of 0.75 to 0.9 times. If this ratio is too small, the strength of the electrode 11 is likely to be reduced. If this ratio is too large, a short circuit may occur between two adjacent electrodes 11.

[0038] The ratio W2 / W1 of the width W2 to the width W1 is preferably in the range of 0.7 to 1.3, and more preferably in the range of 0.8 to 1.2. If this ratio is too large, for example, when a functional device is mounted on the second main surface S2 side, when force is applied to the edge of the first main surface of the electrode 11, the electrode 11 may crack or fall over.

[0039] <Packaged Device> The following describes a packaged device including the above-described electrode-equipped structure 1. Here, the electrode-equipped structure 1 is assumed to be a wiring substrate. As described above, the electrode-equipped structure 1 may also be a functional device.

[0040] Fig. 3 is a schematic diagram illustrating a packaged device according to one embodiment of the present invention, and Fig. 4 is a cross-sectional view illustrating the packaged device shown in Fig. 3 taken along line IV-IV.

[0041] The packaged device 2 includes the electrode-equipped structure 1, the functional device 20, the bonding conductor 22, and the sealing resin 23. FIG. 4 shows one of the multiple electrodes 11. In FIG. 4, the cross section of the packaged device 2 is a second cross section parallel to its height direction. The second cross section is selected, for example, so that the center of gravity of the first main surface or the center of gravity of the second main surface of the electrode 11 is located on the second cross section.

[0042] The functional device 20 is mounted on the electrode-equipped structure 1 via a bonding conductor 22. The functional device 20 includes a functional device body 200 and a plurality of electrodes 201 provided on the functional device body 200. Two or more functional devices 20 may be mounted on the electrode-equipped structure 1.

[0043] Each of the multiple electrodes 201 included in the functional device faces one of the multiple electrodes 11 included in the electrode-equipped structure 1. Each of the multiple electrodes 201 is arranged, for example, so that a line segment connecting the center of gravity of the main surface on the electrode 11 side of that electrode 201 and the center of gravity of the second main surface of the opposing electrode 11 is parallel to the height direction. For example, the multiple electrodes 201 are arranged in a lattice pattern on the functional device body 200, similar to the electrodes 11.

[0044] The joining conductor 22 electrically connects the functional device 20 and the electrode-equipped structure 1. At least a portion of the joining conductor 22 is interposed between the opposing electrodes 11 and 201. The melting point of the joining conductor 22 is lower than the melting points of the electrodes 11 and 201. The material of the joining conductor 22 is, for example, solder. For example, a metal or alloy containing tin can be used as the solder.

[0045] The sealing resin 23 is an insulating resin filled between the functional device 20 and the electrode-equipped structure 1. The sealing resin 23 protects the electrodes 11 and 201 from the external environment. The sealing resin 23 may be made of, for example, epoxy resin.

[0046] At least one of the plurality of electrodes 11 has a side surface at least partially covered by the bonding conductor 22. For example, as shown in Fig. 4, at least one of the plurality of electrodes 11 has a side surface entirely covered by the bonding conductor 22. The other plurality of electrodes 11 may not have a side surface covered by the bonding conductor 22.

[0047] The shape of the electrode 201 is not particularly limited. For example, an electrode having the same shape as the electrode 11 may be used as the electrode 201. The electrode 11 may also be provided at the position of an opening in the insulating resin layer, which is the outermost layer of the structure 10. In this case, it is preferable that the distance from the portion of the electrode 11 corresponding to the constricted portion 111 to the electrode 201 is shorter than the distance from the main surface of the insulating resin layer on the functional device 20 side.

[0048] <Method for manufacturing packaged devices> An example of a method for manufacturing the above-mentioned packaged device will now be described with reference to Figures 5 to 9. In this method, first, an electrode-equipped structure 1 is obtained by the following method.

[0049] First, the structure 10 is prepared. Here, the structure 10 is a wiring board main body including a wiring layer and an insulating layer. The wiring board main body is, for example, a laminate of one or more layers including a wiring layer and an insulating layer. In this process, no electrode is provided on the main surface of the structure 10 on the side where the first conductive layer 12 is formed (hereinafter referred to as the third main surface), but an electrode may be provided on the main surface opposite to this main surface. The wiring layer and insulating layer included in the structure 10 are exposed on the third main surface.

[0050] Next, as shown in FIG. 5, a first conductive layer 12 is formed on the structure 10. The first conductive layer 12 is formed so as to be in contact with the wiring layer exposed on the third principal surface. The first conductive layer 12 may be in contact with the insulating layer exposed on the third principal surface. The material of the first conductive layer 12 can be the same as the material exemplified for the electrode 11. The material of the first conductive layer 12 is preferably the same as the material of the wiring layer included in the structure 10. The first conductive layer 12 can be formed, for example, by plating, sputtering, vapor deposition, or applying a metal paste. The first conductive layer 12 may be composed of multiple layers.

[0051] 6, a resist layer 13 is formed in a pattern on the first conductive layer 12. Here, the resist layer 13 is provided with one or more openings each having a forward tapered cross-sectional shape.

[0052] 7, the openings in the resist layer 13 are filled with a second conductive layer 14. The material of the second conductive layer 14 can be the same as the material exemplified for the electrode 11. The material of the second conductive layer 14 is preferably the same as the material of the first conductive layer 12. The second conductive layer 14 can be formed by, for example, plating, sputtering, vapor deposition, or applying a metal paste.

[0053] Next, the resist layer 13 is removed as shown in Fig. 8. The resist layer 13 is removed by, for example, wet etching or dry etching.

[0054] Next, a portion of the first conductive layer 12 is removed to obtain the electrode 11. The first conductive layer 12 can be removed by, for example, wet etching or dry etching. The first conductive layer 12 is preferably removed by isotropic etching. For example, if the second conductive layer 14 is formed to have a reverse tapered cross-sectional shape, isotropic etching of the first conductive layer 12 results in a first conductive layer 12 having a forward tapered cross-sectional shape. In this way, the electrode-equipped structure 1 shown in FIG. 1 is obtained.

[0055] Next, a functional device 20 including an electrode 201 and a functional device body 200 is prepared. 9, the obtained electrode-equipped structure 1 and functional device 20 are bonded via a bonding conductor 22. Specifically, first, the bonding conductor 22 is placed on at least one of the surfaces of the electrodes 201 and 11. Next, the functional device 20 and the electrode-equipped structure 1 are brought into contact with each other via the bonding conductor 22 so that the electrodes 201 and 11 face each other. Next, the bonding conductor 22 is heated to melt it, and then cooled to electrically connect the electrodes 201 and 11.

[0056] 9, when the joining conductor 22 is melted, a part of the joining conductor 22 interposed between the electrodes 11 and 201 on the electrode 11, which is close to the electrode 201, protrudes from the gap therebetween and moves to the side of the electrode 11. The joining conductor 22 that has moved to the side is then accommodated within the region enclosed by the circumscribed rectangle, particularly in the part corresponding to the constricted portion 111. In this way, the constricted portion 111 restricts the joining conductor 22 from moving to another position.

[0057] Next, the sealing resin 23 described above is filled between the functional device 20 and the electrode-equipped structure 1. In this way, a packaged device 2 is obtained.

[0058] In the above-described method, a wiring substrate body is used as the structure 10, but a functional device body may be used instead of the wiring substrate body. Also, the structure 10 may be supported by a support. In the above-described method, the first conductive layer 12 is removed so as to expose the surface of the structure 10, but the first conductive layer 12 may be removed without exposing the surface of the structure 10.

[0059] <Effects> FIG. 10 is a cross-sectional view schematically illustrating a packaged device according to a comparative example. This packaged device employs a mounting method using a BGA. In the packaged device 2 shown in FIG. 10, a functional device 20 is mounted on a wiring board 21 via a bonding conductor 22. A sealing resin 23 is filled between the functional device 20 and the wiring board 21. The functional device 20 includes a functional device main body 200 and a solder resist layer 202 provided on the functional device main body 200. The solder resist layer 202 has openings, and the functional device main body 200 has electrodes at the positions of the openings. The wiring board 21 includes a wiring board main body 210 and a solder resist layer 212 provided on the wiring board main body 210. The solder resist layer 212 has openings, and the wiring board main body 210 has electrodes at the positions of the openings.

[0060] In recent years, with the increasing integration density of semiconductor devices, there has been a demand for increasing the number of electrodes in a semiconductor device by reducing the area of ​​the main surfaces of the electrodes and narrowing the gap between two adjacent electrodes. However, in the mounting method shown in FIG. 10, a large amount of bonding conductor is required for bonding, and the bonding conductor 22 provided on one electrode is likely to extend into the adjacent electrode. Therefore, narrowing the gap poses a problem of short-circuiting between the electrodes. Therefore, in this case, it is necessary to consider the amount of bonding conductor 22.

[0061] In consideration of the above-mentioned problems, pillar-shaped electrodes 211 as shown in FIGS. 11 and 12 were used for bonding. FIGS. 11 and 12 are cross-sectional views schematically illustrating a packaged device according to a comparative example, which includes pillar-shaped electrodes 211. The packaged device 2 shown in FIGS. 11 and 12 is similar to the packaged device 2 shown in FIG. 10 except that it includes pillar-shaped electrodes 211 as electrodes. FIGS. 11 and 12 illustrate different regions of the same packaged device 2. Specifically, FIG. 11 illustrates a region away from the center of the wiring substrate 21 (hereinafter referred to as the peripheral region), and FIG. 12 illustrates a region near the center of the wiring substrate 21 (hereinafter referred to as the central region). Note that solder resist layers 202 and 212 are omitted in FIGS. 11 and 12.

[0062] In a packaged device 2 including pillar-shaped electrodes 211, the distance between the two opposing electrodes is shorter than in the packaged device 2 shown in Fig. 10, and therefore the amount of joining conductor 22 required for joining is smaller. Therefore, in the packaged device 2 shown in Fig. 11, the joining conductor 22 is less likely to extend onto adjacent electrodes. Therefore, in this packaged device 2, the above-mentioned short circuit is less likely to occur than in the packaged device 2 shown in Fig. 10.

[0063] Incidentally, when the functional device 20 is mounted on the wiring board 21, warping may occur in the wiring board 21. In this case, the distance between the opposing electrodes 211 located in the central region of the wiring board 21 differs from the distance between the opposing electrodes 211 located in the peripheral region of the wiring board 21. Specifically, the distance between the electrodes 211 located in the peripheral region is greater than the distance between the electrodes 211 located in the central region.

[0064] For this reason, the electrode 211 located in the peripheral region requires a larger amount of joining conductor 22 for joining than the electrode 211 located in the central region. Therefore, if the electrode 211 located in the peripheral region is provided with the same amount of joining conductor 22 as the minimum amount of joining conductor 22 required for joining in the electrode 211 located in the central region, there is a risk of a cold joint, i.e., a disconnection defect, occurring.

[0065] On the other hand, the electrode 211 located in the central region requires a smaller amount of joining conductor 22 for joining than the electrode 211 located in the peripheral region. Therefore, if the electrode 211 located in the central region is provided with the same amount of joining conductor 22 as the minimum amount of joining conductor 22 required for joining the electrode 211 located in the peripheral region, the joining conductor 22 is likely to protrude from the main surface of the electrode 211 in a direction perpendicular to the height direction of the electrode 211, as shown in Fig. 12. In this case, a short circuit is likely to occur.

[0066] 11 and 12, if the same amount of joining conductor is provided on each electrode, disconnection or short circuit may occur, which makes it difficult to reduce the distance between two adjacent electrodes 211.

[0067] In the electrode-equipped structure 1 described above, the electrode 11 has the constricted portion 111 described above in the first cross section. As shown in FIG. 1 , the slope of the portion of the electrode 11 corresponding to the side surface changes significantly near the constricted portion 111. Therefore, even if the joining conductor protrudes from the second main surface S2 and moves to the side surface of the electrode 11, the electrode 11 can accommodate the joining conductor in the portion corresponding to the constricted portion 111. Therefore, the joining conductor is less likely to move to the main surface of the structure 10. Therefore, with the electrode-equipped structure 1 described above, it is possible to obtain a packaged device in which the joining conductor is not present on the main surface of the structure 10, or, even if the joining conductor is present on the main surface, the joining conductor is only present in the vicinity of the electrode 11. Therefore, in the electrode-equipped structure described above, short circuits are less likely to occur between two adjacent electrodes.

[0068] Therefore, the above-described electrode 11 allows the distance between two adjacent electrodes to be reduced. Furthermore, the above-described electrode 11 makes it possible to suppress short circuits without drastically reducing the amount of joining conductor, making the above-described disconnection defects less likely to occur. Therefore, the above-described electrode-attached structure 1 can achieve high connection reliability during joining.

[0069] 13 and 14 are cross-sectional views schematically showing an electrode-equipped structure according to a comparative example. The electrode-equipped structure 1 shown in Fig. 13 is the same as the electrode-equipped structure 1 shown in Fig. 1 except that the electrode 11 does not have a portion corresponding to the above-mentioned constricted portion 111 and the width W1 of the first main surface S1 is smaller than the width W2 of the second main surface S2. The electrode-equipped structure 1 shown in Fig. 14 is the same as the electrode-equipped structure 1 shown in Fig. 1 except that the electrode 11 does not have a portion corresponding to the above-mentioned constricted portion 111 and the width W1 of the first main surface S1 is larger than the width W2 of the second main surface S2.

[0070] 13 and 14, the electrode 11 does not have a portion corresponding to the above-mentioned constricted portion, and therefore the joining conductor protruding from the second main surface S2 tends to move along the side surface of the electrode 11 toward the main surface of the structure 10. In particular, in the electrode-equipped structure 1 shown in FIG. 14, the electrode 11 has a cross section parallel to its height direction that is forward tapered, and therefore the joining conductor tends to move toward the main surface of the structure 10. For this reason, short circuits tend to occur in these electrode-equipped structures 1.

[0071] Furthermore, as described above, there is a prior art technique in which the joining conductors are formed by plating to reduce variations in the height of the joining conductors provided on each of the plurality of electrodes 211. However, even with this technique, the variations in the distance between the opposing electrodes caused by the warping described above cannot be eliminated, and therefore the disconnection and short circuit described above may occur.

[0072] <Modification> 15 to 24 are cross-sectional views each showing an electrode structure according to a modified example. As shown in Fig. 15 to 24, in the electrode structure 1 according to the present invention, the shape of the side surface of the electrode 11 and the number and positions of the constricted portions 111 are not limited to the form shown in Fig. 1.

[0073] The electrode-equipped structure 1 shown in FIG. 15 is similar to the electrode-equipped structure 1 shown in FIG. 1, except that the distance of the constricted portion 111 from the structure 10 is smaller than that of the electrode-equipped structure 1 shown in FIG.

[0074] The electrode-equipped structure 1 shown in Fig. 16 is similar to the electrode-equipped structure 1 shown in Fig. 1 except that the distance of the constricted portion 111 from the structure 10 is greater than the distance of the constricted portion 111 shown in Fig. 1. In this case, even if the joining conductor 22 protrudes from the second main surface of the electrode 11 and moves to the side surface of the electrode 11 during mounting, the joining conductor 22 can immediately stay in the portion corresponding to the constricted portion 111.

[0075] 17 is similar to the electrode-equipped structure 1 shown in Fig. 1 except that the electrode 11 has a minimum width in the portion from the vicinity of the first principal surface to the vicinity of the second principal surface and has a substantially cylindrical shape. With such an electrode-equipped structure 1, it is possible to increase the amount of joining conductor 22 that can be accommodated in the portion corresponding to the constricted portion 111.

[0076] The electrode-equipped structure 1 shown in Fig. 18 is similar to the electrode-equipped structure 1 shown in Fig. 1 except that the width W1 is smaller than the width W2, and a pair of side surface portions corresponding to the side surfaces of the electrode 11 in the first cross section are curved. In Fig. 18, the pair of side surface portions are hyperbolic, but they do not have to be hyperbolic. The curved lines may be, for example, parabolic.

[0077] The electrode 11 having the curved side portions can be obtained, for example, by appropriately adjusting the composition of the etching solution and the spray pressure when spraying the etching solution in the step of removing the first conductive layer 12 described with reference to Figure 8.

[0078] The electrode-equipped structure 1 shown in FIG. 19 is similar to the electrode-equipped structure 1 shown in FIG. 18, except that the width W1 described above is larger than the width W2 described above.

[0079] The electrode-equipped structure 1 shown in FIG. 20 is similar to the electrode-equipped structure 1 shown in FIG. 1 except that it has two constricted portions 111, i.e., constricted portions 111A and 111B. When the electrode 11 has two or more constricted portions 111, the two or more constricted portions 111 may have different widthwise dimensions. Furthermore, at least two of the two or more constricted portions 111 may have the same widthwise dimension. Even when the electrode 11 has two or more constricted portions 111, the side portions corresponding to the side surfaces of the electrode 11 in the first cross section may be curved.

[0080] 21 is similar to the electrode-equipped structure 1 shown in Fig. 1 except that in the first cross section, the side surface portion corresponding to the side surface of the electrode 11 in the vicinity of the constricted portion 111 is curved. For example, the electrode 11 shown in Fig. 21 can be obtained by forming the electrode 11 shown in Fig. 1 and then performing side etching in the vicinity of the constricted portion 111.

[0081] The electrode-equipped structure 1 shown in Figure 22 is similar to the electrode-equipped structure 1 shown in Figure 1, except that the distance of the constricted portion 111 from the structure 10 is greater than the above-mentioned distance of the constricted portion 111 shown in Figure 1, and in the first cross section, the portion of the side surface corresponding to the side of the electrode 11 from the first main surface to the constricted portion 111 is curved.

[0082] The electrode structure 1 shown in Figure 23 has two constricted portions 111, namely, constricted portions 111A and 111B, and is similar to the electrode structure 1 shown in Figure 1 except that in the first cross section, the portion of the side surface corresponding to the side surface of the electrode 11 between the constricted portions 111A and 111B is curved.

[0083] The electrode 11 shown in FIG. 23 can be formed, for example, by the following method. First, the structure 10 is prepared. Next, a first resist layer having an opening with a reverse tapered cross-sectional shape is formed on the structure 10. Next, a first conductive layer is filled in the position of this opening. Through this process, a portion corresponding to the portion from the first portion P1 to the constricted portion 111B is obtained. Next, a second resist layer is formed on the first conductive layer and the first resist layer. Next, an opening with a forward tapered cross-sectional shape is formed in the second resist layer at the position of the first conductive layer. Next, this opening is filled with a conductive layer. Next, a third resist layer is formed on the second resist layer and the conductive layer. Next, an opening with a reverse tapered cross-sectional shape is formed at the position of the first conductive layer. Next, this opening is filled with a conductive layer. Through these processes, a portion corresponding to the portion from the constricted portion 111B to the constricted portion 111A is obtained. Next, a second conductive layer is formed by a method similar to the method described with reference to FIGS. 6 to 8. In this way, the electrode 11 shown in FIG. 23 is obtained.

[0084] The electrode structure 1 shown in FIG. 24 has three constricted portions 111, namely constricted portions 111A, 111B, and 111C, and is similar to the electrode structure 1 shown in FIG. 1 except that the side surface of the electrode 11 is curved.

[0085] 20, 23, and 24, the electrode having two or more constricted portions 111 has a plurality of locations in the first cross section where the inclination of the side surface portion corresponding to the side surface of the electrode 11 changes significantly. Therefore, even if the joining conductor 22 is attached to the side surface of the electrode 11, the joining conductor 22 is unlikely to move to the surface of the structure 10. Therefore, a short circuit caused by the joining conductor 22 moving to the surface of the structure 10 is unlikely to occur. The electrode-equipped structure 1 according to the modified example has been described above. The electrode 11 can be formed by combining the above-mentioned methods. [Explanation of symbols]

[0086] 1...structure with electrode, 2...packaged device, 10...structure, 11...electrode, 12...first conductive layer, 13...resist layer, 14...second conductive layer, 20...functional device, 21...wiring board, 22...bonding conductor, 23...encapsulating resin, 111...necked portion, 111A...necked portion, 111B...necked portion, 111C...necked portion, 200...functional device main body, 201...electrode, 202...solder resist layer, 210...wiring board main body, 211...electrode, 212...solder resist layer, CR...dashed line, P1...first part, P2...second part, S1...first main surface, S2...second main surface, W1...width, W2...width.

Claims

1. An electroded structure comprising a structure and a plurality of electrodes provided on the structure, each of the plurality of electrodes includes a first main surface in contact with the structure and a second main surface opposite to the first main surface; An electrode-equipped structure in which each of the plurality of electrodes has a first cross section parallel to its height direction, the first cross section having one or more constricted portions between the first main surface and the second main surface.

2. 2. The electrode-equipped structure according to claim 1, wherein, in the first cross section, an area A1 of a circumscribing rectangle having a smallest area among rectangles circumscribing the contour of the electrode is larger than an area A2 of the electrode.

3. 3. The electroded structure according to claim 2, wherein the ratio A2 / A1 of the area A2 to the area A1 is in the range of 0.70 to less than 1.

0.

4. 2. The electrode-equipped structure according to claim 1, wherein for at least one of the one or more constricted portions, a width CW of the constricted portion in the first cross section is within a range of 0.7 to less than 1.0 times a dimension in a width direction perpendicular to the height direction of each of a first portion P1 of the outline of the first cross section corresponding to the first main surface and a second portion P2 of the outline of the first cross section corresponding to the second main surface.

5. 2. The electroded structure according to claim 1, wherein the center-to-center distance between two adjacent electrodes is within the range of 1.5 to 5 times the diameter of the circle having the smallest area among the circles circumscribing the outline of the second main surface.

6. The electrode-equipped structure according to claim 1 , wherein the structure is in the form of a plate, a sheet, or a film.

7. a wiring board, a joining conductor, and a functional device mounted on the wiring board via the joining conductor; A packaged device in which one of the wiring board and the functional device is an electrode-equipped structure described in any one of claims 1 to 6, and at least a portion of the joining conductor is interposed between the other of the wiring board and the functional device and the multiple electrodes.

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