WO2005069364A1 - Mounted board, electronic component mounting method, electronic component, and wiring board - Google Patents

Abstract

A mounted board (40) comprises a wiring board (20) on which a board electrode (22) is formed, an electronic component (10) having a bump (13), and a nonconductive resin (30) for bonding the electronic component (10) to the wiring board (20). The region between the end (131) of the bump (13) and the board electrode (22) includes contact regions (51) where the end (131) is in contact with the board electrode (22) and a resin interposition region (52) where the nonconductive resin (30) is interposed around the contact regions (51). In the contact regions (51), projections formed on the end (131) of the bump (13) are crushed when brought into contact with and pressed against the board electrode (22), thereby enhancing the reliability of electrical connection between the bump (13) and the board electrode (22).

Description

 Specification

 Mounted board, electronic component mounting method, electronic component, and wiring board

 Technical field

 The present invention relates to a mounted board having an electronic component mounted on a wiring board, an electronic component mounting method for manufacturing the mounted board, an electronic component used for the mounted board, and a wiring board About.

 Background art

 In recent years, along with miniaturization of electric products, a technique of mounting electronic components such as semiconductor bare chips on a wiring board on which electrodes are formed with minute pitches has been used. In this type of mounting, bumps are formed on the electrodes of the electronic component, and the electrodes of the electronic component (hereinafter referred to as “component electrodes”) and the electrodes of the wiring board (hereinafter referred to as “board electrodes”) are formed via the bumps. In many cases, a method of electrically connecting the non-conductive film (NCF) between the electronic component and the wiring board is used. There is also known a method called NSD (Non-Conductive Film Stud-Bump Direct Interconnection) method of mechanically joining an electronic component and a wiring board by the adhesive force of a film.

 [0003] For example, Patent Document 1 describes the following method as a method of manufacturing a mounted board by the NSD method. First, a non-conductive film made of thermosetting resin is adhered on the substrate electrode of the wiring board. Next, the electronic component on which the stud bump, which is a ball bump with a sharp tip, is formed is pressed against the wiring substrate with a predetermined load from above the non-conductive film by aligning the bump with the substrate electrode. The non-conductive film is pushed away at the tip of the bump, so that the bump and the substrate electrode are electrically connected. Then, the non-conductive film is heated and cured in this state, and the electronic component and the wiring board are mechanically joined by the adhesive force of the non-conductive film.

[0004] As a method of mounting an electronic component on a fine substrate electrode, a plurality of fine silver particles are mixed into insulating resin between a bump of the electronic component and a substrate electrode of a wiring board. It is also known to electrically connect the bump and the board electrode and to mechanically connect the electronic component and the wiring board with an anisotropic conductive film or paste interposed therebetween. . For example, Patent Document 2 discloses a mounting method in which an anisotropic conductive paste is interposed, in which a plurality of minute protrusions are formed at the tip of a bump, and the protrusions penetrate an oxide film on a substrate electrode and cut into the bumps. It is described that the reliability of the electrical contact can be improved by connecting with.

 Patent Document 1: International Publication No. 98Z30073 pamphlet

 Patent Document 2: Japanese Patent Application Laid-Open No. 11-111761

 Disclosure of the invention

 Problems to be solved by the invention

 [0005] By the way, in the above-described mounting method using the conventional NSD method, the bumps and tips that are flattened by crushing the tip when handling electronic components are leveled in advance, that is, the tip of the bump is crushed to some extent and flattened. When bumps are used, most of the non-conductive resin is caught between the tip of the bumps and the substrate electrode, and the reliability of the electrical connection is reduced. Further, in the NSD method, since the tip of the bump needs to be sharpened, the distance for pressing the bump against the substrate electrode increases and the load for pressing the bump against the substrate electrode increases. When mounting electronic components on a board, the load at the time of pressing is preferably as small as possible.

 In Patent Document 2, since the bump of the electronic component and the board electrode of the wiring board are joined with a conductive paste interposed therebetween, even if the bump and the land do not directly contact each other, However, conduction between the two is possible. Therefore, it is not necessary to consider the problem of the decrease in the reliability of the electrical connection when the non-conductive resin is interposed as described above.

 The present invention has been made in order to solve the above-mentioned problems, and has a mounted board and an electronic component mounting that can improve the reliability of electrical connection between a bump of an electronic component and a substrate electrode of a wiring board. It is an object to provide a method, an electronic component, and a wiring board.

 Means for solving the problem

[0007] In order to achieve the above object, the present invention is configured as follows.

According to the mounted board of the first aspect of the present invention, a mounted board on which electronic components are mounted, the wiring board having a plurality of board electrodes formed thereon, and the board being electrically connected to the plurality of board electrodes, respectively. An electronic component having a plurality of bumps formed thereon, and at least the plurality of A non-conductive resin for adhering the wiring board and the electronic component around the bumps, wherein a bonding region between each tip of the plurality of bumps and the substrate electrode facing the tip is There are a plurality of contact areas where the tip and the substrate electrode are in contact with each other, and a resin interposed area where the non-conductive resin is interposed around the plurality of contact areas.

 [0008] In the mounted substrate according to the first aspect, the plurality of contact regions may be regions where a plurality of protrusions formed at the tips of the plurality of bumps are crushed.

 [0009] In the mounted substrate according to the first aspect, the plurality of contact regions may be regions where a plurality of protrusions formed on the substrate electrode are crushed.

[0010] Further, in the mounted board of the first aspect, the contact region may be formed densely at a central portion of the joining region, and may be formed coarser at a peripheral portion as compared with the central portion.

 [0011] By changing the formation density of the contact region per unit area in the bonding region in the bonding region in this way, when the bump and the substrate electrode are bonded while pushing off the non-conductive resin, the bonding region power is reduced. The flow resistance of the non-conductive resin extruded is reduced, and the non-conductive resin is sealed between the bump and the substrate electrode to prevent the conduction between the bump and the substrate electrode from being hindered. And improve the reliability of the electrical connection.

 [0012] In the mounted board according to the first aspect, the resin intervening region may extend radially from a central portion to a peripheral portion of the bonding region.

 [0013] With this configuration, when the bump and the substrate electrode are joined together while pushing away the non-conductive resin, the non-conductive resin that also extrudes the bonding area force can be efficiently discharged. . Therefore, it is possible to reduce the possibility that the non-conductive resin is sealed between the bump to be bonded and the substrate electrode to prevent conduction between the bump and the substrate electrode, thereby improving the reliability of the electrical connection. be able to.

 [0014] In the mounted board according to the first aspect, the contact region may be formed in a staggered shape at a center portion of the bonding region, which is coarser at a peripheral portion than at the central portion. .

[0015] As described above, when the bump and the substrate electrode are joined, the non-conductivity from the joining region is Considering the drainage of resin, it is preferable that the contact area is formed densely at the center of the joining area and coarsely at the peripheral edge. On the other hand, considering the case where the bump and the substrate electrode are displaced from each other, the reliability of the electrical connection is improved when the contact area is closer at the periphery of the bonding area. As described above, the countermeasures are inconsistent between the case where the non-conductive resin is discharged from the joint region and the case where the bump and the substrate electrode are misaligned. Therefore, when the contact area is made dense at the peripheral edge of the bonding area in consideration of the above-described position shift, the bonding area is formed in a staggered shape, so that a non-conductive area is formed as compared with the case where the bonding area is formed randomly. Resin drainage can be improved. Therefore, the reliability of the electrical connection between the bump and the substrate electrode can be improved while considering the displacement between the bump and the substrate electrode.

 Further, the mounted board according to the second aspect of the present invention is a mounted board on which electronic components are mounted,

 A wiring board on which a plurality of board electrodes are formed,

 An electronic component having a plurality of bumps electrically connected to the plurality of substrate electrodes, respectively.

 The contact area between each tip of the plurality of bumps and the substrate electrode facing the tip is a plurality of contact areas where the tip contacts the substrate electrode, and a non-contact area around the plurality of contact areas. A resin-intervening region in which conductive resin intervenes, wherein the contact area occupies different portions in a central portion and a peripheral portion of the joining region.

 [0017] In the second aspect, the contact region can be formed densely at the central portion and coarser at the peripheral portion than at the central portion, and conversely, coarser at the central portion. The peripheral portion can be formed denser and staggered than the central portion.

 Further, in the second aspect, the resin intervening region may extend radially from the central portion toward the peripheral portion.

[0018] By changing the formation density of the contact region per unit area in the bonding region in the bonding region in this manner, when the bump and the substrate electrode are bonded with the non-conductive resin interposed therebetween, the bonding region is formed. The flow resistance of the non-conductive resin extruded is reduced, and the non-conductive resin is sealed between the bump to be bonded and the substrate electrode so that the conduction between the bump and the substrate electrode is reduced. It is possible to reduce the hindrance of communication and improve the reliability of the electrical connection.

 An electronic component mounting method according to a third aspect of the present invention is an electronic component mounting method for mounting an electronic component on a wiring board, wherein each of the plurality of board electrodes formed on the wiring board has Forming a plurality of projections on each of the plurality of bumps formed on the electronic component, applying a non-conductive resin having adhesive property at least around the plurality of substrate electrodes, and applying the electronic component to the wiring board. The plurality of bumps are electrically connected to the plurality of substrate electrodes by pressing and curing the non-conductive resin.

 [0020] In the electronic component mounting method according to the third aspect, when the plurality of protrusions are formed, a mold having irregularities formed on the plurality of bumps or the plurality of substrate electrodes is pressed. Is also good.

 [0021] In the third aspect, when the plurality of protrusions are formed, the protrusions may be formed densely at a central portion of the bump or the substrate electrode, and may be formed coarsely at a peripheral portion as compared with the central portion. Alternatively, conversely, the protrusions may be formed densely in the central portion and in a staggered manner in the peripheral portion compared to the central portion.

 Further, an electronic component according to a fourth aspect of the present invention is an electronic component mounted on a wiring board, wherein the component main body of the electronic component having a plurality of component electrodes and a non-conductive non-conductive material having an adhesive property. A plurality of bumps formed on the plurality of component electrodes for electrical connection with a plurality of board electrodes formed on the wiring board while sandwiching grease, wherein each of the plurality of bumps is A plurality of protrusions are provided at the tip.

 [0023] In the electronic component according to the fourth aspect, the maximum height Ry of the protrusion may be not less than 2 μm and not more than 15 m.

 [0024] In the fourth aspect, the bump-formed surface of the bump may be convex toward the substrate electrode. The bumps may be formed densely at the center of the bump-formed surface of the bumps, and may be formed coarser at the periphery than at the center, or conversely, at the center. The portion may be formed denser and staggered than the central portion.

The electronic component according to the fifth aspect of the present invention is an electronic component mounted on a wiring board. A component body of the electronic component having a plurality of component electrodes,

 A plurality of bumps formed on the plurality of component electrodes for electrically connecting to a plurality of substrate electrodes formed on the wiring board,

 Each of the plurality of bumps includes a plurality of protrusions on the uneven surface at the tip end,

 The protrusions have different formation densities at a central portion and a peripheral portion of the unevenness forming surface.

 [0026] In the fifth aspect, the protrusion may be formed densely at the central portion and coarser at the peripheral portion than at the central portion. Conversely, the protrusion may be coarser at the central portion. The peripheral portion may be formed denser and staggered than the central portion.

 A wiring board according to a sixth aspect of the present invention is a wiring board for mounting an electronic component, wherein a plurality of wiring boards formed on the electronic component while sandwiching a non-conductive resin having an adhesive property with a substrate body are provided. And a plurality of substrate electrodes formed to be electrically connected to the bumps, and each of the plurality of substrate electrodes has a plurality of protrusions on the electrode surface.

 [0028] In the wiring substrate according to the sixth aspect, the maximum height Ry of the protrusion on the electrode surface may be not less than 2 μm and not more than 15 μm.

 [0029] In the sixth aspect, the protrusion may be formed densely at a central portion of the electrode surface, and may be formed coarser at a peripheral portion as compared with the central portion. The peripheral portion may be formed densely and in a staggered shape as compared with the central portion.

 [0030] The wiring board according to a seventh aspect of the present invention is a wiring board for mounting electronic components, wherein:

 A plurality of substrate electrodes formed for electrical connection with a plurality of bumps formed on the electronic component,

 Each of the plurality of substrate electrodes includes a plurality of protrusions on the electrode surface,

 The protrusions have different formation densities at a central portion and a peripheral portion of the surface.

[0031] In the seventh aspect, the protrusions may be formed densely at the central portion, and may be formed coarser at the peripheral portion than at the central portion. The perimeter The portion may be formed densely and in a staggered shape as compared with the central portion.

 The invention's effect

 According to the present invention, since a plurality of contact regions and resin interposed regions are formed in the bonding region, the reliability of electrical connection between the bumps of the electronic component and the substrate electrodes of the wiring board is improved. However, a mounted board can be obtained.

 Brief Description of Drawings

 FIG. 1 is a flowchart showing a flow of mounting electronic components according to the first embodiment.

[FIG. 2] FIG. 2 is a cross-sectional view showing a state in which bumps are formed on component electrodes of the component body. FIG. 3] FIG. 3 is a cross-sectional view showing a state in which a mold is positioned on the bumps of the component body. FIG. 4 is a cross-sectional view showing a state where the mold is pressed against the bumps of the component body.

 圆 5] FIG. 5 is a cross-sectional view showing a state where a plurality of protrusions are formed on the bumps of the component body,

 [FIG. 6] FIG. 6 is a perspective view showing an uneven surface of a mold.

 [FIG. 7] FIG. 7 is a cross-sectional view showing a state in which non-conductive resin is applied to substrate electrodes of the wiring board. [8] FIG. 8 is a cross-sectional view of a mounted board in which electronic components are mounted on the wiring board. Sectional view showing the configuration,

 [FIG. 9] FIG. 9 is a plan view showing a contact area between a bump of an electronic component and a board electrode of a wiring board.

FIG. 10 is a plan view showing another example of a contact area between a bump of an electronic component and a board electrode of a wiring board,

 [FIG. 11] FIG. 11 is a cross-sectional view showing a state where a bump having a sharp tip is displaced and is not sufficiently in contact with a substrate electrode.

 [FIG. 12] FIG. 12 is a cross-sectional view showing a state in which bumps having irregularities at the tips are displaced and are in contact with substrate electrodes.

 FIG. 13 is a cross-sectional view showing a state where a mold is positioned on a substrate electrode of a wiring board according to the second embodiment of the present invention;

FIG. 14 is a cross-sectional view showing a state where a mold is pressed against a substrate electrode of a wiring board, [15] FIG. 15 is a cross-sectional view showing a configuration of the wiring board in a state where a plurality of protrusions are formed on the substrate electrode of the wiring board.

 [FIG. 16] FIG. 16 is a cross-sectional view showing a state in which a non-conductive resin is applied on the substrate electrode of the wiring board.

17] FIG. 17 is a cross-sectional view showing a configuration of a mounted board in a state where electronic components are mounted on a wiring board.

 FIG. 18 is a modified example of the cross-sectional view shown in FIG. 5, showing a state in which a plurality of protrusions are formed on a bump having a convex-concave surface.

 FIG. 19 is a plan view showing another example of a contact area between a bump of an electronic component and a board electrode of a wiring board.

 FIG. 20 is a plan view showing still another example of a contact region between a bump of an electronic component and a board electrode of a wiring board;

 FIG. 21 is a plan view showing still another example of a contact region between a bump of an electronic component and a board electrode of a wiring board,

 [FIG. 22] FIG. 22 is a view corresponding to FIG. 19, showing the roughness and density of bumps and bumps formed on a substrate electrode,

 FIG. 23 is a view corresponding to FIG. 21, and is a view showing the roughness and density of bumps and bumps formed on a substrate electrode.

Explanation of symbols

 10 Electronic components

 11 Parts body

 12 Component electrode

 13 Bump

 131, 131a Tip of the pump

 133 protrusion

 134 Uneven surface

 134a center

134b Perimeter 20 Wiring board

 21 Board body

 22 ,: 22a substrate electrode

 30 Non-conductive resin

 40 Mounted board

 51 Contact area

 52 Resin intervening area

 53 bonding area

 53a center

 53b Perimeter

 80, 80a type

 221 electrode surface

 222 irregularities

 223 protrusion

 BEST MODE FOR CARRYING OUT THE INVENTION

 An embodiment of the present invention will be described below with reference to the drawings. In each figure, the same parts! /, And the same reference numerals.

 FIG. 1 is a flowchart showing a flow of mounting an electronic component according to the first embodiment of the present invention, and includes a bump forming step which is a part of a manufacturing process of the electronic component. FIGS. 2 to 5 are views for explaining a state in which a plurality of projections are formed on bumps in a process of manufacturing an electronic component.

In the bump formation, first, in step S11, a plurality of bumps 13 are formed on a plurality of component electrodes 12 formed on the component body 11, as shown in FIG. The component body 11 is a semiconductor bare chip, and the component electrode 12 is formed of aluminum. The bumps 13 are ball bumps with sharp tips, so-called stud bumps, which are formed by melting the tip of a gold wire by electric discharge, crimping the melted portion to the component electrode, and tearing the gold wire from the crimped portion. You. The tip 13 of the bump 13 formed in this manner is sharpened by tearing the gold wire. Next, in step S 12, irregularities including a plurality of projections are formed on each of the tip portions 131 of the bumps 13 formed on the component body 11. As shown in FIG. 3, the unevenness of the tip 131 is determined by positioning the uneven surface 81 of the mold 80 for forming the unevenness toward the tip 131 of the bump 13 on the component electrode 12 as shown in FIG. After pressing the surface 81 against the tip 131, the mold 80 is released to form the structure as shown in FIG. Thereby, the manufacture of the electronic component 10 with bumps for mounting is completed.

 FIG. 6 is a perspective view showing an uneven surface 81 of the mold 80. The mold 80 is formed of stainless steel, and as shown in FIG. 6, the uneven surface 81 has a large number of projections and depressions 82. The unevenness 82 can take various shapes such as a pyramid and a cone, and is not particularly limited. Further, a plurality of types of irregularities 82 may be mixed on one irregular surface 81. The concave-convex surface 81 has irregularities 82 formed at random by rubbing the surface of stainless steel with sandblast. Note that regular irregularities 82 may be formed by etching or the like. Generally, the portion of the bump 13 that contacts the component body 11 has a diameter of about 80 m, and the tip 131 has a diameter of about 40 m. Therefore, in order to form several or dozens of irregularities 82 according to the size of the tip 131, as shown in FIG. 5, the maximum height Ry of the surface roughness of the tip 131 is set as shown in FIG. It is more preferably from 2 μm to 15 μm, and still more preferably from 5 μm to 10 μm. Therefore, the maximum height of the surface roughness of the uneven surface 81 of the mold 80 is also 2 μm or more and 15 μm or less, preferably 5 μm or more and 10 μm or less. Then, by pressing the uneven surface 81 of the mold 80 against the tip 131 of the bump 13, the tip 131 has the preferable surface roughness.

 As described above, the surface roughness is preferably set to 5 μm or more and 10 μm or less, because the non-conductive resin interposed between the bump 13 and the substrate electrode 22 is used as described later. A force for displacing the bump 13 and the substrate electrode 22 by joining the above-mentioned surface roughness. The above-mentioned surface roughness is also a force for improving the escape of the non-conductive resin 30 at the time of joining.

Through the above steps, the electronic component 10 includes the component body 11 having the plurality of component electrodes 12 and the plurality of bumps 13 formed on the plurality of component electrodes 12 of the component body 11. In addition, each of the plurality of bumps 13 has an unevenness 132 at the tip 131. In the bump 13, a plurality of protrusions of the unevenness 132 of the tip 131 Used for electrical connection with the board.

 FIG. 7 and FIG. 8 are cross-sectional views showing how the electronic component 10 is mounted on the wiring board 20.

 When the electronic component 10 having the bumps 13 formed with the projections 132 at the tips 131 is prepared, as shown in FIG. 7, the wiring board 20 having the board electrodes 22 formed on the board body 21 is prepared. In step S21, an epoxy resin, which is an adhesive thermosetting resin having a bonding property, is applied as a non-conductive resin 30 on the substrate electrode 22 at least around the substrate electrode 22. The substrate body 21 is formed of glass epoxy resin or polyimide resin, and the substrate electrode 22 is formed of copper as a part of a wiring pattern (not shown) formed on the substrate body 21. .

 Next, as shown in FIG. 8, the electronic component 10 and the board main body 21 are positioned so that the tip 131 of the bump 13 of the electronic component 10 can come into contact with the board electrode 22 of the wiring board 20. The electronic component 10 is pressed against the wiring board 20 with a predetermined load. As a result, the plurality of projections of the unevenness 132 of the tip 131 are pushed away while sandwiching the non-conductive resin 30 and come into contact with the substrate electrode 22, and are crushed to some extent on the surface of the substrate electrode 22, and It is electrically connected to. At the same time, the electronic component 10 is heated, and the non-conductive resin 30 is hardened (Step S22).

 FIG. 9 is a plan view showing a bonding region 53 at a contact interface between the tip 131 of the bump 13 and the substrate electrode 22. As shown in FIGS. 8 and 9, between the tip 131 of the bump 13 and the substrate electrode 22, there are a plurality of contact areas 51 where the tip 131 and the substrate electrode 22 are in contact, and a plurality of contact areas 51. And a resin intervening region 52 in which the non-conductive resin 30 intervenes. The contact region 51 is a region where the plurality of protrusions 133 formed on the tip 131 of the bump 13 are crushed, and is a region where the bump 13 and the substrate electrode 22 are electrically connected. When regular bumps are formed on the bumps 13 by etching or the like, the contact regions 51 are regularly scattered in the resin intervening region 52 as illustrated in FIG.

Here, since the non-conductive resin 30 slightly shrinks during curing, the non-conductive resin 30 is interposed between the component main body 11 and the substrate main body 21 and at the same time as the tip 131 of the bump 13 By interposing also in the resin interposed area 52 between the substrate electrode 22 and the non-conductive resin 30, The electronic component 10 and the wiring board 20 are mechanically joined by the adhesive force, and the bumps 13 and the board electrodes 22 are attracted to each other to be surely electrically connected.

As shown in FIG. 8, the mounted substrate 40 manufactured through the above steps is electrically connected to the wiring substrate 20 on which the plurality of substrate electrodes 22 are formed and the plurality of substrate electrodes 22 of the wiring substrate 20. Electronic component 10 on which a plurality of bumps 13 connected to each other are formed, and a non-conductive resin 30 for bonding the wiring board 20 and the electronic component 10 to each other. The region between the tip 131 of the bump 13 and the corresponding substrate electrode 22 includes a plurality of contact regions 51 and a resin interposition region 52 around which the non-conductive resin 30 is interposed. Having

As described above, in the mounted substrate 40 according to the first embodiment, the bump 13 and the substrate electrode 22 are formed by forming the plurality of protrusions 133 at the tip 131 of the bump 13 of the electronic component 10. The non-conductive resin 30 is prevented from being caught almost all over the contact surface of the electronic component 10, and the reliability of the electrical connection between the bump 13 of the electronic component 10 and the substrate electrode 22 of the wiring substrate 20 is improved. . Since the non-conductive resin 30 intervenes around the plurality of contact regions 51 and the resin-intervening region 52 exists, the shrinkage of the non-conductive resin 30 during hardening causes the bump 13 and the substrate electrode 22 to contact each other. Are reliably attracted to each other. As a result, the reliability of the electrical connection between the bump 13 and the substrate electrode 22 is further improved. Further, the plurality of protrusions 133 formed on the tip 131 of the bump 13 are crushed, so that the tip 131 and the substrate electrode 22 come into contact with each other in a large area, and thereby, the contact between the bump 13 and the substrate electrode 22 is formed. The reliability of the electrical connection is further improved. Furthermore, the load at the time of mounting and the amount of crushing of the tip can be reduced as compared with the case where the tip of the bump 13 is sharp at one point.

By the way, for example, when the tip of the bump 13 is sharp at one point, as shown in FIG. 11, when the bump 13 and the substrate electrode 22 are displaced by a distance 60 and the tip comes off the substrate electrode 22, The tip of the bump 13 is bent so as to fall off from the substrate electrode 22, and the bump 13 is not sufficiently contacted. That is, when the projection of the tip 131 is crushed to secure a contact area, the tip needs to be placed on the upper surface of the substrate electrode 22. Such poor contact is particularly remarkable when the wiring board 20 has flexibility. On the other hand, when the tip portion 131 of the bump 13 has the unevenness 132 as in the electronic component 10 according to the first embodiment, as shown in FIG. As described above, even when the bump 13 and the substrate electrode 22 are displaced by the distance 60 and the center of the bump 13 is not placed on the substrate electrode 22, the area at the tip of the bump 13 is reduced to one place by the formation of the unevenness 132. Since it is larger than the case where it is sharp, a part of the tip portion 131 is surely in contact with the surface of the substrate electrode 22, and the electrical connection between the bump 13 and the substrate electrode 22 is ensured.

 That is, in the electronic component 10 according to the first embodiment, since the tip portion 131 of the bump 13 has the concave and convex 132, the allowable amount of the positioning error between the bump 13 and the substrate electrode 22 increases. Thus, the yield of mounting the electronic component 10 can be improved.

 Also, as described above, since the bump 13 is formed by tearing the gold wire, the pedestal portion, which is a large-diameter portion, and the tip formed on the pedestal portion and having a smaller diameter than the pedestal portion. This is a two-stage shape composed of the portion 131 and the unevenness 132 is formed on the tip portion 131. Therefore, at the time of bonding between the bump 13 and the substrate electrode 22, the bump 13 has a shape that allows the non-conductive resin 30 to be easily displaced and pressed.

 Next, a second embodiment of the present invention will be described. In the electronic component mounting according to the second embodiment, instead of the step (steps Sl12 and S12) of forming bumps on the tip of the electronic component bump in the first embodiment, bumps are formed on the substrate electrodes of the wiring board. Is formed.

 FIGS. 13 to 15 are cross-sectional views illustrating a state in which a plurality of protrusions are formed on a substrate electrode as a part of a manufacturing process of a wiring board. The wiring board 20 before the formation of the irregularities is the same as that of the first embodiment, and a copper wiring pattern (not shown) is formed on a substrate body 21 formed of glass epoxy resin, polyimide resin, or the like. A substrate electrode 22 is formed as a part. Note that the substrate electrode 22 has a shape different from that of the first embodiment. As shown in FIG. 13, the unevenness of the surface 221 of the substrate electrode 22 is determined by positioning the mold 80a on the substrate electrode 22 and pressing the mold 80a against the surface 221 of the substrate electrode 22 as shown in FIG. When separated, they are formed as shown in FIG. In the following description, reference numeral 22a is assigned to the substrate electrode after the formation of the unevenness, and reference numeral 221a is assigned to the surface thereof.

As in the first embodiment, the mold 80a is formed of stainless steel, and the portion facing the substrate electrode 22 protrudes, as shown in FIG. When It has become. The surface 221a of the substrate electrode 22a has a maximum surface roughness Ry of 2 m or more and 15 μm or less as shown in FIG. 15 in the same manner as the tip portion 131 of the bump 13 of the first embodiment. It is more preferable that the distance be 5 m or more and 10 m or less. Therefore, the maximum height of the surface roughness of the uneven surface 81a of the mold 80a is also 2 μm or more and 15 m or less, preferably 5 μm or more and 10 m or less. Then, by pressing the uneven surface 81a of the mold 80a against the surface 221 of the substrate electrode 22, the substrate electrode 22a having the above-described surface roughness is obtained.

 The reason why the surface roughness of the surface 221a of the substrate electrode 22a is set to the above value is the same as the reason described above for the bump 13!

 By performing the above steps, as shown in FIG. 15, the wiring substrate 20 includes the substrate main body 21 and the wiring pattern including the plurality of substrate electrodes 22a formed on the substrate main body 21. Each of the substrate electrodes 22a has irregularities 222 on the force surface 221a. In the substrate electrode 22a, a plurality of protrusions of the irregularities 222 on the surface 221a are used for electrical connection with electronic components described below.

 FIG. 16 and FIG. 17 are cross-sectional views showing how the electronic component 10 is mounted on the wiring board 20. In the second embodiment, as shown in FIG. 16, an electronic component 10 having a bump 13 formed on a component electrode 12 of a component body 11 is prepared, and at least the substrate electrode 22a is formed on the substrate electrode 22a of the wiring board 20. Epoxy resin, which is a paste-like thermosetting resin having adhesive properties around the periphery, is provided as a non-conductive resin 30. This operation corresponds to step S21 shown in FIG. Unlike the first embodiment, the bump 13 is formed by leveling the tip of a stud bump formed of gold, that is, flattening the tip by crushing the tip to some extent.

Next, as shown in FIG. 17, the tip 131 a of the bump 13 of the electronic component 10 is positioned so as to be able to contact the board electrode 22 a of the wiring board 20, and the electronic component 10 is turned toward the wiring board 20. Is pressed with a predetermined load. As a result, the non-conductive resin 30 is sandwiched between the bump 13 and the substrate electrode 22a, and the non-conductive resin 30 is pushed away by the plurality of protrusions 223 on the surface 22la of the substrate electrode 22a. The tip portion 13la is electrically connected to the substrate electrode 22a while crushing a plurality of protrusions on the surface 221a of the substrate electrode 22a to some extent. At the same time, the electronic component 10 is heated and the non-conductive resin 30 is cured (Step S22) At this time, the bonding area 53 at the contact interface between the tip 131a of the bump 13 and the substrate electrode 22a is formed by a plurality of contact areas where the tip 131a and the substrate electrode 22a are in contact, as in FIG. There is a region 51 and a resin-interposed region 52 around which the non-conductive resin 30 is interposed around the plurality of contact regions 51. The contact region 51 is a region where a plurality of protrusions 223 included in the unevenness 222 formed on the surface 221a of the substrate electrode 22a are crushed, and are electrically connected between the bump 13 and the substrate electrode 22a. Area.

 Here, since the non-conductive resin 30 slightly shrinks during curing, the non-conductive resin 30 is interposed between the component main body 11 and the substrate main body 21 and the tip 13 la of the bump 13 is formed. The electronic component 10 and the wiring board 20 are mechanically joined by the adhesive force of the non-conductive resin 30 by interposing also in the resin intervening region 52 on the contact surface between the substrate and the substrate electrode 22a. The bump 13 and the substrate electrode 22a are attracted to each other and are reliably connected electrically.

 As shown in FIG. 17, the mounted board 40 manufactured through the above steps is electrically connected to the wiring board 20 on which the plurality of board electrodes 22a are formed and the plurality of board electrodes 22a of the wiring board 20. An electronic component 10 having a plurality of bumps 13 connected thereto, respectively, and a non-conductive resin 30 for bonding the wiring board 20 and the electronic component 10 are provided. The region between the portion 131a and the substrate electrode 22a has a plurality of contact regions 51 and a resin interposed region 52 around which the non-conductive resin 30 is interposed.

 As described above, in the mounted board 40 according to the second embodiment, the bump 13 and the board electrode 2 are formed by forming the plurality of protrusions 223 on the surface 221a of the board electrode 22a of the wiring board 20. Non-conductive resin 30 is prevented from being pinched over almost the entire area between the bumps 2a and 2a, and the reliability of electrical connection between the bumps 13 of the electronic component 10 and the board electrodes 22a of the wiring board 20 is improved. Similarly to the first embodiment, the presence of the resin interposed area 52 in which the non-conductive resin 30 intervenes around the plurality of contact areas 51, as in the first embodiment, allows the bump 13 and the substrate electrode 22a to be in contact with each other. The reliability of the electrical connection is further improved. In addition, the plurality of protrusions 223 formed on the surface 221a of the substrate electrode 22a are crushed, so that the front end 131a of the bump 13 and the substrate electrode 22a come into contact with a large area, and the reliability of the electrical connection is further improved Can be further enhanced.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made. In the first embodiment, the bumps 13 formed in step S11 are not limited to so-called stud bumps formed by melting the tips of gold wires, but are ball bumps formed by other methods. May be! /.

[0061] In the first embodiment, the plurality of protrusions 133 of the tip portion 131 of the bump 13 may be formed randomly or regularly, and extend along the tip surface. It may be a streak-like projection such as a straight line or a curve. Further, the plurality of protrusions 133 of the tip portion 131 of the bump 13 are not limited to the pressing of the mold 80, and may be formed by another method. Also in the second embodiment, the plurality of protrusions 223 on the surface 221a of the substrate electrode 22a may be formed randomly or regularly, and may be streaks extending along the surface. For example, it may be a linear or curved streak-like projection. Further, the plurality of protrusions 223 on the surface 221a of the substrate electrode 22a are not limited to the pressing of the mold, and may be formed by another method.

 For example, the pointed tip 131 of the bump 13 illustrated in FIG. 3 is pressed against a flat surface in advance and crushed, that is, leveling is performed, and a plasma treatment is performed on the flat surface of the tip 131. The unevenness may be formed by processing, blasting, sanding, or the like. Also, the bump 13 may be a flat metal bump formed on the component electrode 12 or even in this case, the bump is easily formed on the surface of the bump by pressing the mold having the unevenness. be able to. In the case of a bump, even if bumps are formed by plasma treatment, blasting, filing, or the like, the bump growth rate may be varied on the component electrode 12 or the bump before the bump may be formed. By forming irregularities on the electrode 12 by etching or the like, bumps having irregularities can be formed.

 [0063] A force that is normally in a state of contact between the bump 13 and the substrate electrodes 22 and 22a. For example, if the bump 13 is formed of gold and the surface of the substrate electrode is also plated with gold, the bonding is performed during bonding. When the temperature is increased, the gold on the bumps 13 may diffuse and form a metal-bonded state at the atomic level. That is, the contact area 51 between the bump 13 and the substrate electrodes 22 and 22a in the above embodiment may be in a physical metal bonding state.

In the first and second embodiments, the component body 11 of the electronic component 10 is not limited to a semiconductor chip, but may be, for example, a small component electronic component such as a packaged electronic component. Various other electronic components having poles may be used. The substrate body of the wiring board 20 is not limited to glass epoxy resin / polyimide resin, but may be made of other resin / ceramic, glass, or the like, for example.

[0064] In the first and second embodiments, the non-conductive resin is not limited to a paste having fluidity, but may be a sheet-like resin. In this case, the sheet-like non-conductive resin is applied to the periphery of the substrate electrode by covering the substrate electrode and pasting it on the wiring board 20.

[0065] In the first and second embodiments, the molds 80 and 80a are not limited to stainless steel, and may be made of any material that is harder than a pump or a substrate electrode. There may be.

 In the case where the electronic component before bump formation, that is, the component body 11 is delivered to the mounting facility and the bump formation of the electronic component is performed at the mounting facility, a plurality of protrusions are formed on the bump 13. The mounting method according to the first embodiment is suitable, while an electronic component having leveled bumps is delivered to a mounting facility, and an electronic component having leveled bumps is mounted on a wiring board. In this case, the mounting method according to the second embodiment in which a plurality of protrusions are formed on the substrate electrode 22 of the wiring substrate 20 is preferable.

 Further, in the first embodiment, the unevenness forming surface 134 of the bump 13 on which the unevenness 132 is formed has a convex shape, that is, a state in which the bump 13 and the substrate electrode 22 are joined, as shown in FIG. In addition, the shape may be convex toward the substrate electrode 22 side. With this configuration, when the bump 13 and the substrate electrode 22 are joined, first, the central portion of the bump 13 contacts the substrate electrode 22 and then contacts the peripheral portion of the bump 13 with a force. To go. Therefore, the non-conductive resin 30 interposed between the bump 13 and the substrate electrode 22 can be smoothly discharged to the outside of the bump 13 without being confined between the bump 13 and the substrate electrode 22. Therefore, the reliability of the electrical connection between the bump 13 and the substrate electrode 22 can be further improved. In addition, the formation of the convex-shaped uneven surface 134 can be achieved by using a concave mold.

In the first and second embodiments, as shown in FIG. 19, in the central portion 53a of the bonding region 53 between the bump 13 and the substrate electrodes 22, 22a, the contact region 51 per unit area The number is so high that the peripheral portion 53b of the joining region 53 is formed coarser than the central portion 53a. The bumps 132 may be formed on the pump 13 or the bumps 222 may be formed on the substrate electrode 22a. In other words, in the bump 13, as shown in FIG. 22, the unevenness 132 is formed densely in the central portion 134a of the unevenness forming surface 134, and the unevenness 132 is formed coarsely in the peripheral portion 134b as compared with the central portion 134a. In the substrate electrode 22a, as shown in FIG. 22, the unevenness 222 is formed densely in the central portion 221c of the surface 221 and the unevenness 222 is formed coarsely in the peripheral portion 221d as compared with the central portion 221c. The central portion 53a and the peripheral portion 53b of the joining region 53 are not clearly defined regions.For example, the central portion 53a of the joining region 53 has a central force up to approximately half the radius of the joining region 53. A region up to approximately half the radius and up to the outer periphery of the joining region 53 can be defined as a peripheral portion 53b. The definition of the central portion and the peripheral portion of the bump 13 and the substrate electrode 22a also corresponds to the definition of the central portion 53a and the peripheral portion 53b in the bonding region 53.

 As described above, since the bump 13 and the substrate electrodes 22 and 22a are joined while pushing away the non-conductive resin 30 interposed therebetween, the bumps 13 and the irregularities 132 are formed so that the peripheral portion 53b is rougher than the central portion 53a. By forming the unevenness 222, the escape of the non-conductive resin 30 at the time of joining is improved. Therefore, the reliability of the electrical connection between the bump 13 and the substrate electrodes 22 and 22a can be further improved. In FIG. 19, the shape of the contact region 51 is shown as being substantially circular for convenience, but the shape is not limited to a circle.

 In the first and second embodiments, the contact region 51 and the resin intervening region 52 are provided to improve the escape of the non-conductive resin 30 when the bump 13 and the substrate electrodes 22 and 22a are joined. Rather than being formed randomly over the entire joining region 53, as shown in FIG. 20, the resin drainage in which the resin interposed region 52 extends radially from the central portion 53a of the joining region 53 toward the peripheral edge 53b. The bumps 132 and the bumps 222 may be formed on the bump 13 and the substrate electrode 22 so as to form the use passage 52a. Also according to this configuration, at the time of bonding, the non-conductive resin 30 is easily discharged to the outside of the bonding region 53 by passing through the resin discharge passage 52a, so that the electrical connection between the bump 13 and the substrate electrode 22 is made. Reliability can be further improved.

When the escape of the non-conductive resin 30 at the time of joining is considered, as described above with reference to FIG. 19, the contact area 5 1 at the center 53 a is smaller than the peripheral area 53 b of the joining area 53. However, as shown in FIG. 11, even if the bump 13 and the substrate electrodes 22 and 22a are displaced, as shown in FIG. It is preferable to increase the number of contact regions 51 in the peripheral portion 53b as compared with the central portion 53a of the joining region 53. Therefore, in the first and second embodiments, as shown in FIG. 21, the contact region 51 at the peripheral portion 53b of the joining region 53 becomes dense, and the contact region 51 at the central portion 53a is compared with the peripheral portion 53b. In order to reduce the flow resistance when the non-conductive resin 30 is discharged and to make it easy to escape, the contact area 51 is formed in a staggered manner at the peripheral edge 53b. 132 and unevenness 222 may be formed. In other words, in the bump 13, as shown in FIG. 23, the central portion 134a of the concave / convex forming surface 134 roughens the concave / convex 132.The peripheral edge 134b forms the concave / convex 132 denser and staggered than the central portion 134a. . In the substrate electrode 22a, as shown in FIG. 23, the central portion 221c of the surface 221 roughens the irregularities 222 at the peripheral portion 221d. The irregularities 222 are formed densely and staggered at the peripheral edge 221d as compared with the central portion 221c.

 [0072] Note that by appropriately combining any of the various embodiments, the effects of the respective embodiments can be achieved.

 Although the present invention has been fully described in connection with preferred embodiments thereof with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art. It is to be understood that such changes and modifications are intended to be included therein without departing from the scope of the invention as set forth in the appended claims.

 Industrial applicability

The present invention relates to a mounted board having an electronic component mounted on a wiring board, an electronic component mounting method for manufacturing the mounted board, an electronic component used for the mounted board, and a wiring board Applicable to

Claims

The scope of the claims  [1] A mounted board on which electronic components are mounted,  A wiring board (20) on which a plurality of board electrodes (22, 22a) are formed;  An electronic component (10) having a plurality of bumps (13) electrically connected to the plurality of substrate electrodes, respectively;  A non-conductive resin (30) for bonding the wiring board and the electronic component at least around the plurality of bumps;  With  A bonding area (53) between each tip (131, 131a) of each of the plurality of bumps and the substrate electrode facing the tip forms a plurality of contact areas (51) where the tip contacts the substrate electrode. ), And a resin interposed area (52) in which the non-conductive resin is interposed around the plurality of contact areas. 2. The mounted substrate according to claim 1, wherein the plurality of contact regions are regions where a plurality of protrusions (133) formed at the tips of the plurality of bumps are crushed. 3. The mounted board according to claim 1, wherein the plurality of contact areas are areas where a plurality of protrusions (223) formed on the board electrode are crushed. 4. The mounted board according to claim 1, wherein the contact region is formed densely at a central portion (53a) of the joining region and coarser at a peripheral portion (53b) than at the central portion. [5] The mounted substrate according to claim 1, wherein the resin intervening region radially extends from a central portion (53a) of the joining region toward a peripheral portion (53b). [6] The mounting according to claim 1, wherein the contact region is formed denser and staggered at a center portion (53a) of the joining region at a rough peripheral portion (53b) than at the center portion. Board. [7] A mounted board on which electronic components are mounted,  A wiring board (20) on which a plurality of board electrodes (22, 22a) are formed;  An electronic component (10) having a plurality of bumps (13) electrically connected to the plurality of substrate electrodes, respectively. A bonding area (53) between each tip (131, 131a) of the plurality of bumps and the substrate electrode facing the tip is formed by a plurality of contact areas where the tip contacts the substrate electrode. Region (51), and a resin interposed region (52) in which a non-conductive resin (30) is interposed around the plurality of contact regions,  A mounted substrate, wherein the contact area occupies different portions in a central part (53a) and a peripheral part (53b) of the bonding area. [8] The mounted board according to claim 7, wherein the contact region is formed densely at the central portion and coarser at the peripheral portion than at the central portion. [9] The mounted substrate according to claim 7, wherein the resin intervening region radially extends from the central portion toward the peripheral portion. 10. The mounted substrate according to claim 7, wherein the contact area is formed in a staggered manner at the central portion, which is coarser at the peripheral portion than at the central portion. [11] An electronic component mounting method for mounting an electronic component (10) on a wiring board (20),  Forming a plurality of projections (133, 223) on each of the plurality of substrate electrodes (22, 22a) formed on the wiring board or on the plurality of bumps (13) formed on the electronic component, Applying a non-conductive resin (30) having an adhesive property around the plurality of substrate electrodes;  An electronic component mounting method, wherein the plurality of bumps are electrically connected to the plurality of substrate electrodes by pressing the electronic component against the wiring board and curing the non-conductive resin.  12. The electronic component according to claim 11, wherein when forming the plurality of protrusions, a mold (80, 80a) in which unevenness (82) is formed on the plurality of bumps or the plurality of substrate electrodes is pressed. Implementation method.  [13] When forming the plurality of projections, the bumps or the substrate electrodes are formed densely at a central portion (53a) and coarsely formed at a peripheral portion (53b) as compared with the central portion. Term 1 Electronic component mounting method according to 1. [14] When forming the plurality of protrusions, the protrusions are denser and staggered at the peripheral portion (53b), which is rough at the central portion (53a) of the bump or the substrate electrode, than at the central portion. 12. The electronic component mounting method according to claim 11, wherein the electronic component is formed. [15] An electronic component (10) mounted on a wiring board (20), A component body (11) of the electronic component having a plurality of component electrodes (12);  Formed on the plurality of component electrodes to electrically connect to a plurality of board electrodes (22, 22a) formed on the wiring board while sandwiching a non-conductive resin (30) having adhesiveness A plurality of bumps (13),  An electronic component, wherein each of the plurality of bumps includes a plurality of protrusions (133) at a tip end. 16. The electronic component according to claim 15, wherein a maximum height Ry of the projection is 2 m or more and 15 m or less.  17. The electronic component according to claim 15, wherein the unevenness forming surface (134) of the bump is convex toward the substrate electrode.  [18] The protrusions are densely formed at the central portion (134a) of the bump forming surface (134) at the peripheral portion.  16. The electronic component according to claim 15, wherein in (134b), the electronic component is formed coarser than the central portion.  [19] The bump is formed densely and staggered at a central portion (134a) of the bump forming surface (134) at the peripheral portion (134b) as compared with the central portion. Electronic parts described in 15.  [20] An electronic component (10) mounted on a wiring board (20),  A component body (11) of the electronic component having a plurality of component electrodes (12);  A plurality of bumps (13) formed on the plurality of component electrodes for electrically connecting to a plurality of board electrodes (22, 22a) formed on the wiring board,  Each of the plurality of bumps has a plurality of protrusions (133) on the uneven surface (134) at the tip end,  The electronic component, wherein the protrusions have different formation densities in a central portion (134a) and a peripheral portion (134b) on the uneven surface. 21. The electronic component according to claim 20, wherein the protrusion is formed densely at the central portion and coarser at the peripheral portion than at the central portion. 22. The electronic component according to claim 20, wherein the protrusions are coarser in the central portion and are denser and staggered in the peripheral portion than in the central portion. [23] A wiring board for mounting electronic components, Board body (20),  A plurality of substrate electrodes (22, 22a) formed to electrically connect with a plurality of bumps (13) formed on the electronic component (10) while sandwiching a non-conductive resin (30) having an adhesive property. ) And  A wiring board, wherein each of the plurality of substrate electrodes includes a plurality of protrusions (223) on an electrode surface (221).  24. The wiring board according to claim 23, wherein a maximum height Ry of the protrusion on the electrode surface is 2 μm or more and 15 m or less.  25. The wiring substrate according to claim 23, wherein the protrusions are formed densely at a central portion (221c) of the electrode surface and coarsely formed at a peripheral portion (221d) as compared with the central portion. 26. The wiring board according to claim 23, wherein the protrusions are formed densely and staggered at a central portion (221c) of the electrode surface at a rough peripheral portion (221d) as compared to the central portion. [27] A wiring board for mounting electronic components,  Board body (20),  A plurality of substrate electrodes (22, 22a) formed for electrical connection with a plurality of bumps (13) formed on the electronic component (10).  Each of the plurality of substrate electrodes includes a plurality of protrusions (223) on an electrode surface (221), and the protrusions have different formation densities at a central portion (221c) and a peripheral portion (221d) on the surface. Wiring board. 28. The wiring board according to claim 27, wherein the protrusion is formed densely at the central portion and coarser at the peripheral portion than at the central portion. 29. The wiring substrate according to claim 27, wherein the protrusions are rougher in the central portion and are formed densely and in a staggered manner in the peripheral portion compared to the central portion.