JP2006165240A - Protruding electrode for electronic component connection, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protruding electrode for electronic component connection for absorbing stress caused by heating and pressurizing in a bonding process and the warpage of a substrate in mounting an electronic component on the substrate. <P>SOLUTION: The protruding electrode 3 for electronic component connection connects a terminal electrode 2 of the electronic component 1 to a wiring electrode of the substrate corresponding to the terminal electrode 2. The protruding electrode 3 is formed on the terminal electrode 2 of the electronic component 1 or the wiring electrode of the substrate, has a cross sectional shape with a waisted portion 6 on its center portion, and is made of a composite material in which at least one of granular resins 4 and bubbles is dispersed in a metal material. In this configuration, a shape effect and the elastic force of the material can release the stress applied to the protruding electrode 3. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a protruding electrode for connecting an electronic component to a substrate, and more particularly to a protruding electrode for connecting an electronic component with high reliability and a method for manufacturing the same.

  In recent years, a semiconductor device such as a large-scale integrated circuit device having a large area and a large number of connection electrodes has been formed in a bare chip configuration in order to be mounted on an electronic device that is required to be small, thin, and lightweight, typified by a portable terminal. There are many examples of mounting on a substrate in a packaged configuration. In such a mounting method, bonding is generally performed using bump electrodes called bumps. However, a large stress is applied to the bump electrodes due to the thermal stress in the bonding process or the difference in thermal expansion coefficient between the semiconductor element and the substrate. There are many. In order to relieve these stresses, for example, a method has been developed in which the cross-sectional shape of the protruding electrode is reduced to a drum shape to relieve the stress (see, for example, Patent Document 1). In this conventional method, solder is used as a material for the protruding electrode, and the solder is deformed by separating the electronic component from the substrate in a molten state or a softened state at the time of mounting, thereby obtaining a drum shape. Yes.

  Further, as shown in FIG. 9, there is also shown a structure in which a drum-like protruding electrode 43 is formed on the terminal electrode 42 of the semiconductor element 41 (see, for example, Patent Document 2). Such a drum-shaped protruding electrode 43 is formed as follows. First, etching is performed from both sides of the polyimide resin film to form an opening having a drum-shaped cross section. Next, a polyimide resin film is attached to the semiconductor substrate, and the drum-shaped opening is filled with solder. Next, by removing the polyimide resin, a protruding electrode 43 having a drum shape on the terminal electrode 42 and made of solder is obtained. In this method, the solder is filled by filling with solder paste or molten solder.

  According to these methods, it is possible to easily form a protruding electrode that is resistant to fatigue failure, and to obtain a protruding electrode forming method for a semiconductor element capable of improving productivity as a semiconductor device.

  In addition, there is also shown a method of absorbing stress by the elastic force of the material itself, which is a conventional cylindrical protruding electrode (see, for example, Patent Document 3). FIG. 10 is a cross-sectional view of the protruding electrode in which the conventional resin particles are dispersed. As shown in FIG. 10, a terminal electrode 42 is formed on the semiconductor element 41. The semiconductor element 41 is provided with a protective film 44 for protecting a circuit formation surface (not shown). The protruding electrode 45 formed on the terminal electrode 42 contains resin particles 46 in a dispersed manner.

  Thus, the protruding electrode 45 containing the resin particles 46 is formed, for example, by mixing and dispersing the resin particles 46 in the electrolytic solution and performing electroplating while stirring. By adopting such a configuration, it is said that the stress generated during bonding can be relieved by the elastic recovery force of the protruding electrode 45 including the resin particles 46. The resin particles 46 are made of acrylic, styrene, or silicon resin having a size of about 1 μm to 5 μm.

In addition, a method has been developed in which solder bumps having uniform voids are formed inside to form a sponge shape to relieve thermal stress during bonding (see, for example, Patent Document 4).
JP 59-5637 A JP-A-9-115912 Japanese Patent Laid-Open No. 5-144817 Japanese Patent Laid-Open No. 11-214447

  However, in the first conventional example, the solder is deformed so that the solder is held in a molten state or a softened state during mounting and the electronic component is separated from the substrate. For this reason, a large variation in the drum shape tends to occur due to a separation distance or a variation in the shape of the protruding electrode.

  In the second conventional example, when the solder paste is printed and filled in the drum-shaped opening formed in the resin film, it is necessary to once melt the solder. Therefore, the flatness of the upper surface is deteriorated by this melting. In addition, even when the molten solder is filled, it is relatively difficult to reliably flatten the upper surface. Further, since the material of the drum-like protruding electrode formed on the terminal electrode of the semiconductor substrate is solder, it is difficult to maintain the shape when the solder is melted by heating at the time of joining the semiconductor element and the substrate. However, it is difficult to ensure the bonding strength unless it is sufficiently melted. In other words, when the protruding electrodes are formed by solder, the drum-shaped shape is not maintained if the solder is melted during the connection work, so it is necessary to connect at a temperature at which the solder does not melt, and the range of optimum joining conditions is extremely There is a problem that it is limited to.

  In the above third conventional example, resin particles are dispersed and contained in the protruding electrode, and the protruding electrode has an elastic force, which is effective for stress relaxation. However, since there is no constricted portion in the central portion, it is externally applied. When stress is applied, the stress tends to concentrate on either joint. Therefore, peeling of the joint portion or peeling of the terminal electrode may occur. The fourth conventional example has the same problem as the third example.

  The present invention solves the above-described problems, and relieves stress applied to the entire protruding electrode by the material configuration and its shape effect, so that even when the difference in thermal expansion coefficient between the electronic component and the substrate is large, highly reliable mounting is achieved. An object of the present invention is to provide a protruding electrode for connecting an electronic component and a method for manufacturing the same.

  In order to achieve this object, the protruding electrode for connecting an electronic component of the present invention is a protruding electrode for connecting a terminal electrode of an electronic component and a wiring electrode of a substrate corresponding to the terminal electrode. Is a composite material formed on a terminal electrode of an electronic component or a wiring electrode of a substrate, having a cross-sectional shape provided with a constriction at the center, and at least one of granular resin and bubbles dispersed in a metal material It has the composition which consists of.

  With this configuration, the constricted portion at the center of the protruding electrode and the elastic deformation force of the composite material forming the protruding electrode can reliably relax even if a large stress is applied to the bonded portion. As a result, a highly reliable connection configuration can be realized even with an electronic component and a substrate that have greatly different thermal expansion coefficients.

  In the above configuration, the metal material constituting the protruding electrode has a melting point higher than the temperature at which the terminal electrode and the wiring electrode are bonded to each other by the protruding electrode, and retains its shape even after the applied pressure for bonding is applied. It is good also as a material to do. By adopting this configuration, deformation due to temperature during bonding can be prevented, and a protruding electrode that does not change in shape before and after bonding can be obtained, so even if stress due to a difference in thermal expansion coefficient is applied, the bonded portion or terminal Generation | occurrence | production of peeling of an electrode etc. can be suppressed and a highly reliable connection structure is realizable.

  In the above structure, a bonding metal layer may be formed on the surface of the protruding electrode that is bonded to the terminal electrode or the wiring electrode. In this case, the bonding metal layer may be composed of only the metal material. Alternatively, a metal material having a melting point lower than that of the metal material may be used for the bonding metal layer.

  With such a configuration, the terminal electrode of the electronic component for connection with the protruding electrode or the wiring electrode of the substrate and the protruding electrode can be reliably bonded with high bonding strength. In particular, by selecting a metal whose melting point of the bonding metal layer is lower than the melting point of the metal material constituting the protruding electrode, it is possible to realize a protruding electrode having a wide bonding condition range while reducing deformation of the protruding electrode.

  In addition, the method for manufacturing a protruding electrode for connecting an electronic component according to the present invention has a cross-sectional shape in which a constricted portion is provided at a central portion on a terminal electrode of an electronic component or a wiring electrode of a substrate corresponding to the terminal electrode. In addition, the method includes a method in which a protruding electrode made of a composite material in which at least one of granular resin and bubbles is dispersed in a metal material is formed by a plating method. This composite material is foamable by a method in which a granular resin is dispersed and contained in a metal material by a resin dispersion plating method, or a resin dispersion plating method including a foamable resin that contains a substance that generates bubbles when heated. A method may be used in which after forming a metal film containing dispersed resin, the metal film is heated to generate bubbles from the foamable resin.

  By these methods, it is possible to easily form a protruding electrode made of a composite material having a constricted portion at the center and containing at least one of a granular resin and bubbles in the metal material.

  Further, in the above method, the first opening having a shape in which the opening area of the upper surface portion is smaller on the terminal electrode of the electronic component or on the wiring electrode of the substrate corresponding to the terminal electrode than on the lower surface portion in contact with the terminal electrode or the wiring electrode. A step of forming a first resist film having an opening, a first plating step of forming a first protruding electrode filling the first opening with a composite material, and a first protrusion filled in the first opening. Forming a second resist film on the first resist film in which a second opening having a shape in which the surface of the electrode is exposed and the upper surface of the electrode has a larger cross-sectional area than the surface of the first protruding electrode; A method may include a second plating step of forming a second protruding electrode continuous from one protruding electrode and filling the second opening with a composite material, and a step of removing the first resist film and the second resist film. .

  By this method, it is possible to easily form a protruding electrode having a cross-sectional shape in which at least one of the granular resin and bubbles is dispersed and has a constricted portion at the center.

  Further, in the above method, a step of forming a resist film provided with a cross-sectional opening having a constricted portion at a central portion on a terminal electrode of an electronic component or a wiring electrode of a substrate, and a protruding electrode filling the opening It is good also as a method including the process of removing the resist film, and the plating process of forming a composite material.

  Further, in the above method, a step of applying a negative resist film on the terminal electrode of the electronic component or the wiring electrode of the substrate, and the terminal electrode on the negative resist film at a predetermined position on the terminal electrode or the wiring electrode Alternatively, the step of forming an unexposed portion that becomes the second opening with a smaller cross-sectional area of the upper surface portion than the surface in contact with the wiring electrode by selective exposure, and has a light shielding property on the negative resist film A step of forming a light shielding film, a step of applying a positive resist film on the light shielding film, and a positive resist film located on an unexposed portion of the negative resist film, the lower surface portion of which is an unexposed portion. A step of selectively exposing to form an exposed portion that is the same as the cross-sectional area of the upper surface portion and whose upper surface portion is larger than the cross-sectional area of the lower surface portion and becomes the first opening; and developing the positive resist film Positive resist for exposed areas Removing and forming the first opening; etching removing the light shielding film exposed on the lower surface of the first opening; and developing the negative resist film to remove the negative resist in the unexposed area. The method may include a step of forming a second opening connected to the first opening, and a plating step of forming a protruding electrode with a composite material in the first opening and the second opening.

  By these methods, it is possible to easily form a resist film having a cross-sectional opening having a constricted portion at the center, and to form a protruding electrode made of a composite material by plating so as to fill the opening. it can. In addition, according to these methods, as the cross-sectional shape, for example, a shape in which trapezoidal upper surfaces are bonded together, a drum shape, or a central cross-sectional area is small, and a cross-sectional area continuously from the upper surface part to the lower surface part. It is possible to easily produce protruding electrodes having various shapes such as a shape in which the angle changes or a shape in which a part of the center is cylindrical. In addition, as the cross-sectional shape of the protruding electrode of the present invention, various shapes such as an elliptical shape, a circular shape, a polygonal shape such as a quadrangular shape, or a shape in which a polygonal end portion is chamfered can be selected.

  The protruding electrode for connecting an electronic component according to the present invention has a constricted portion at the center in the cross-sectional shape, and a metallic material constituting the protruding electrode is dispersed and contained in granular resin or bubbles. As a result, in addition to the stress relieving effect due to the constricted portion, the stress can be relieved by the large elastic deformation force of the metal material containing granular resin or bubbles, so that the combination of the substrate and the electronic component having different thermal expansion coefficients is possible. Also has a great effect that a highly reliable connection structure can be realized.

  Furthermore, according to the method for manufacturing a protruding electrode for connecting an electronic component of the present invention, a protruding electrode having a constricted portion at the center in a cross-sectional shape and dispersed in granular resin or bubbles is easily formed with good shape reproducibility. There is a great effect that can be done.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same element and description may be abbreviate | omitted.

(First embodiment)
FIG. 1 is a cross-sectional view of a protruding electrode for connecting an electronic component according to a first embodiment of the present invention. As shown in FIG. 1, in the present embodiment, a configuration in which a protruding electrode 3 made of a composite material in which a granular resin 4 is dispersed in a metal material is formed on a terminal electrode 2 of an electronic component 1 will be described as an example. To do. The protruding electrode 3 has a constricted portion 6 at the center in the height direction, and the upper surface thereof is a connection surface for connecting to a wiring electrode (not shown) of a substrate (not shown) corresponding to the terminal electrode 2. 5

  Such a protruding electrode 3 is formed of a composite material in which a granular resin 4 is dispersed in a metal material, and its production is preferably performed by a resin dispersion plating method. Gold (Au), silver (Ag), copper (Cu), nickel (Ni), or the like can be used as a metal material constituting the composite material. Further, as the granular resin 4, a resin obtained by atomizing an acrylic resin, a styrene resin, a silicon resin, or the like can be used.

  When such a composite material including the granular resin 4 is used as the protruding electrode 3, the bonding with the wiring electrode of the substrate can be performed by, for example, ultrasonic bonding. In the case of ultrasonic bonding, bonding can be performed at a temperature sufficiently lower than the melting point of the metal material and with a pressing force that does not cause the plastic electrode 3 to undergo large plastic deformation. Accordingly, since the shape of the protruding electrode 3 is maintained even after the bonding, even if a thermal stress or a stress due to an external impact is applied, the stress can be efficiently absorbed.

  FIG. 2 is a process cross-sectional view for explaining the method of manufacturing the protruding electrode for connecting an electronic component in the present embodiment.

  First, as shown in FIG. 2A, the first resist film 7 is formed on the main surface of the electronic component 1 (for example, a wafer on which a large number of semiconductor elements are formed), and the lower surface portion in contact with the terminal electrode 2 The first opening 8 having a smaller opening area on the upper surface is formed on the terminal electrode 2. In order to form such an inversely tapered opening in the resist film, a method of adjusting the pre-bake time after applying the photoresist, a rotary exposure method of exposing from an oblique direction when exposing using a photomask, or the like is used. it can.

  Next, as shown in FIG. 2B, the first protrusion 8 made of metal such as gold (Au), silver (Ag), copper (Cu), nickel (Ni) is plated inside the first opening 8 by plating. Electrode 9 is formed. This is the first plating step. The first protruding electrode 9 contains the granular resin 4 in a dispersed manner. The upper surface of the first protruding electrode 9 only needs to be on the same plane as or below the surface of the first resist film 7. That is, the upper surface of the first protruding electrode 9 may be in the first opening 8.

  Next, as shown in FIG. 2C, a second resist film 10 is formed so as to cover the first resist film 7 and the first protruding electrode 9, exposed and developed, and connected to the first protruding electrode 9. Two openings 11 are formed. The second opening 11 is formed such that the lower surface thereof coincides with the upper surface of the first protruding electrode 9 and the cross-sectional area of the upper surface is larger than that of the lower surface.

  Next, as shown in FIG. 2D, second protrusions made of metal such as gold (Au), silver (Ag), copper (Cu), nickel (Ni), etc. are formed in the second opening 11 by plating. The electrode 12 is formed. This is the second plating step. The second protruding electrode 12 also contains the granular resin 4 in a dispersed manner.

  Thereafter, by removing the first resist film 7 and the second resist film 10, the drum-like protruding electrode 3 having the constricted portion 6 at the center is formed as shown in FIG.

  2 shows an example in which the granular resin 4 is dispersed and contained in the first protruding electrode 9 and the second protruding electrode 12, but the granular resin is included in at least one of the first protruding electrode 9 and the second protruding electrode 12. The same effect can be obtained also by dispersing at least one of the bubbles.

  As a method of dispersing the granular resin in the protruding electrode, a method of dispersing an acrylic resin, styrene resin, silicon resin or the like in an electrolytic solution and performing electrolytic plating while stirring can be used.

  In addition, as a method of dispersing and containing bubbles in the protruding electrode, electrolytic plating is performed by adding a substance that generates bubbles by heating, for example, sodium bicarbonate or an organic solvent encapsulated in a resin capsule to the electrolytic solution. The method can be used. In this case, by heating after forming the bumps, the above substances can be generated or decomposed to form bubbles in the protruding electrodes.

  Further, the position of the constricted portion 6 of the protruding electrode 3, the cross-sectional areas of the upper and lower surface portions of the protruding electrode 3, and the cross-sectional area of the constricted portion 6 are not limited to the shapes shown in FIG.

  Next, a first modification of the protruding electrode for mounting electronic components according to the present embodiment will be described.

  FIG. 3 is a cross-sectional view showing a first modification of the protruding electrode for mounting electronic components. The protruding electrode 3 of the first modification is for bonding that does not include the granular resin 4 on the upper surface of the protruding electrode 3 shown in FIG. 1, that is, the surface bonded to the wiring electrode (not shown) of the substrate (not shown). It is characterized in that the metal layer 13 is provided. In this case, the upper surface of the bonding metal layer 13 becomes the new connection surface 5.

  Note that the bonding metal layer 13 may be made of the same material as that of the protruding electrode 3. In this case, the bonding strength between the bonding metal layer 13 and the wiring electrode of the substrate can be increased. Furthermore, if the surface of the bonding metal layer 13 and the surface of the wiring electrode are respectively cleaned and bonded by plasma treatment or the like, strong bonding is possible even at room temperature, and the generation of thermal stress during bonding can be greatly suppressed. it can.

  Further, as the bonding metal layer 13, a material having a melting point lower than that of the metal material constituting the protruding electrode 3 may be used. For example, tin (Sn) or solder that can be melted and bonded at a relatively low temperature can be used. When the material constituting the protruding electrode 3 is gold (Au) and the bonding metal layer 13 is solder, it is desirable to provide a barrier metal layer under the bonding metal layer 13. By adopting such a configuration, it is possible to prevent a reaction between solder and gold (Au) during bonding. As the solder, most lead (Pb) free solder can be used. Furthermore, a low melting point metal such as indium (In) can be used.

  By bonding the electronic component and the substrate using the protruding electrode 3 of the first modified example in which the bonding metal layer 13 is formed on the upper surface portion of the protruding electrode 3 formed of the composite material as described above, the stress is reduced. Not only can it be relaxed, but also the bonding strength can be increased.

  The tip surface of the protruding electrode 3 shown in FIG. 3, that is, the bonding metal layer 13 can be formed by the method described below. The first method of forming the bonding metal layer 13 is to form the protruding electrode 3 to a predetermined thickness and then plate it in a separately prepared plating tank, so that it does not contain any granular resin or bubbles and is bonded. A plating layer made of a material suitable for the above can be formed. Further, the second method of forming the bonding metal layer 13 is to stop the stirring in the plating tank at the final stage of the plating process for forming the protruding electrode 3, that is, at the stage where the protruding electrode having a substantially predetermined height is formed. By continuing plating in such a state, a plating layer containing almost no granular resin or bubbles can be formed.

  In FIGS. 1 to 3, only one terminal electrode 2 and a protruding electrode 3 formed thereon are shown in the electronic component 1, but in general, the electronic component 1 includes a plurality of electronic components 1. The terminal electrode 2 is provided, and the protruding electrodes 3 are formed according to the number of terminal electrodes 2.

  For example, when the electronic component 1 is a bare-chip semiconductor element or a packaged semiconductor device, it may have several tens to several hundred terminal electrodes. Even in such an electronic component 1, a protruding electrode 3 having a constricted portion 6 in the center and a granular resin 4 dispersed in a metal material is formed on the terminal electrode 2, and a substrate ( If it is connected to a wiring electrode (not shown), a highly reliable mounting configuration can be realized. That is, when a semiconductor element or a semiconductor device as described above is mounted on a substrate made of resin, the thermal expansion coefficients of the semiconductor element or semiconductor device that is the electronic component 1 and the substrate are greatly different, and a large amount of heat is generated during or during use. Stress is applied between the protruding electrode and the protruding electrode and the terminal electrode or between the protruding electrode and the wiring electrode. Furthermore, not only the thermal stress but also a stress may be applied by receiving a force from an external impact or the like. However, with the protruding electrode according to the present embodiment, this stress can be absorbed by the shape having the constricted portion and the large elastic deformation force of the composite material containing the granular resin in a dispersed manner. Therefore, it is possible to suppress the occurrence of defects at the joints and the protruding electrodes.

(Second Embodiment)
FIG. 4 is a cross-sectional view of a protruding electrode for connecting an electronic component according to a second embodiment of the present invention. As shown in FIG. 4, in the present embodiment, the outline 14 of the side surface portion of the protruding electrode 3 is on the inner side with respect to the straight line 15 connecting the upper surface portion or the lower surface portion of the protruding electrode 3 and the constricted portion 6. And it is arcuate.

  That is, the cross-sectional area of the constricted portion 6 is smaller than the cross-sectional area of the lower surface portion of the protruding electrode 3 that is in contact with the terminal electrode 2 of the protruding electrode 3 formed on the terminal electrode 2 of the electronic component 1 and the connection surface 5 that is connected to the wiring electrode. Is formed small. Further, the protruding electrode 3 is also formed of a composite material including the granular resin 4.

  By adopting such a configuration, even when a semiconductor element or a semiconductor device is mounted on a substrate made of a resin, even if a thermal stress or a mechanical stress generated due to an external impact is applied, an arc shape is applied. This stress can be absorbed by the shape having the constricted portion 6 and the large elastic deformation force of the composite material containing the granular resin 4 in a dispersed manner. Therefore, it is possible to suppress the occurrence of defects at the joints and the protruding electrodes.

  Next, a method for manufacturing the protruding electrode for connecting an electronic component in the present embodiment will be described with reference to FIG.

  First, as shown in FIG. 5A, a resist having a drum-shaped opening 17 having a drum-shaped cross section on a terminal electrode 2 of an electronic component 1 (for example, a wafer on which a large number of semiconductor elements are formed). A film 16 is formed. Such a resist film 16 can be formed by forming a drum-shaped sheet by etching from both sides of the resin film and affixing this sheet to the main surface of the electronic component 1.

  Next, as shown in FIG. 5B, a granular resin made of a metal such as gold (Au), silver (Ag), copper (Cu), nickel (Ni) is plated in the drum-shaped opening 17 by plating. The protruding electrode 3 containing 4 in a dispersed manner is formed. Next, as shown in FIG. 5C, by removing the resist film 16, it is possible to form the protruding electrode 3 having the constricted portion 6 in the center portion and containing the granular resin 4 in a dispersed manner.

  5 shows an example in which the granular resin 4 is dispersedly contained in the protruding electrode 3 formed in the step of FIG. 5, but bubbles may be dispersedly contained instead of the granular resin 4.

  As a method of dispersing the granular resin in the protruding electrode, a method of dispersing an acrylic resin, styrene resin, silicon resin or the like in an electrolytic solution and performing electrolytic plating while stirring can be used.

  In addition, as a method of dispersing and containing bubbles in the protruding electrode, electrolytic plating is performed by adding a substance that generates bubbles by heating, for example, sodium bicarbonate or an organic solvent encapsulated in a resin capsule to the electrolytic solution. The method can be used. In this case, by heating after forming the bumps, the above substances can be generated or decomposed to form bubbles in the protruding electrodes.

  In addition, about the constriction part 6 shown in FIG. 4 or FIG. 5, although the case where it exists in the approximate center part of the height direction of each protrusion electrode 3 is shown, the position and sectional area are changed suitably as needed. Also good. Furthermore, the cross-sectional areas of the lower surface portion and the upper surface portion of the protruding electrode 3 may not be the same.

  That is, the height, bottom area, and constriction area of each protruding electrode can be determined in consideration of the material, shape, thickness, etc. of the electronic component and the substrate.

  Note that the material described in the first embodiment is used as the material used for each protruding electrode.

  4 and 5, only one terminal electrode 2 and the protruding electrode 3 formed thereon are shown in the electronic component 1, but the electronic component 1 generally has a plurality of terminal electrodes 2. The protruding electrodes 3 are also formed in accordance with the number of terminal electrodes 2.

  For example, when the electronic component 1 is a bare-chip semiconductor element or a packaged semiconductor device, it may have several tens to several hundred terminal electrodes. Even in such an electronic component 1, a protruding electrode 3 having a constricted portion 6 in the center and a granular resin 4 dispersed in a metal material is formed on the terminal electrode 2, and a substrate ( If it is connected to a wiring electrode (not shown), a highly reliable mounting configuration can be realized. That is, when a semiconductor element or a semiconductor device as described above is mounted on a substrate made of resin, the thermal expansion coefficients of the semiconductor element or semiconductor device that is the electronic component 1 and the substrate are greatly different, and a large amount of heat is generated during mounting or during use. Stress is applied between the protruding electrode and the protruding electrode and the terminal electrode or between the protruding electrode and the wiring electrode. Furthermore, not only the thermal stress but also a stress may be applied by receiving a force from an external impact or the like. However, with the protruding electrode according to the present embodiment, this stress can be absorbed by the shape having the constricted portion and the large elastic deformation force of the composite material containing the granular resin in a dispersed manner. Therefore, it is possible to suppress the occurrence of defects at the joints and the protruding electrodes.

  In the present embodiment, the case where the connection surface 5 is the upper surface of the protruding electrode 3 has been described. However, a bonding metal layer 13 similar to that shown in FIG. 3 may be provided on the upper surface of the protruding electrode 3. .

(Third embodiment)
FIG. 6 is a cross-sectional view of a protruding electrode for connecting an electronic component according to a third embodiment of the present invention. As shown in FIG. 6, in the present embodiment, the protruding electrode 3 has a cylindrical constricted portion 18 in the middle in the height direction. In this case, the stress applied to the protruding electrode 3 is received by the cylindrical constricted portion 18. That is, in the protruding electrode shown in the first embodiment, the oblique portion of the drum is a straight line and intersects at one point, whereas in the structure shown in FIG. 6, the oblique portion is once cylindrical constricted portion 18. Intersects with a diagonal part. For this reason, the angle at which the straight portions intersect is more gentle, so that the stress is further dispersed.

  Next, a method for manufacturing the protruding electrode for connecting an electronic component according to the present embodiment will be described with reference to FIGS.

  FIG. 7 is a process cross-sectional view for explaining the first half of the manufacturing method, and FIG. 8 is a process cross-sectional view for explaining the second half of the manufacturing method.

  First, as shown in FIG. 7A, a negative first photoresist film 19 is formed on the main surface of an electronic component 1 having a terminal electrode 2 (for example, a wafer on which a large number of semiconductor elements are formed). To do. Next, the first photoresist film 19 is pre-baked, but the pre-bake time at that time is shorter than the standard.

  Next, as shown in FIG. 7B, exposure is performed using a first photomask 20 having a first opaque region 21 in a portion corresponding to the terminal electrode 2. The arrow indicates the ultraviolet light 22 used for exposure. Note that the first photoresist film 19 under the first opaque region 21 is an unexposed region.

  In this way, as shown in FIG. 7C, the first exposed region 23 and the first unexposed region 24 are formed on the electronic component 1. The first unexposed region 24 has a so-called reverse taper shape in which the cross-sectional area of the upper surface portion is smaller than the lower surface portion. That is, since the first photoresist film 19 has a pre-bake time shorter than the standard, photocuring does not proceed in the depth direction. The exposed area and the unexposed area cannot be directly observed optically, but FIG. 7 (c) schematically shows this state.

  Next, as shown in FIG. 7 (d), a light-shielding film for covering the first unexposed area 24 and the first exposed area 23 and blocking light used in the next exposure process, for example, metal A film 25 is formed. Next, as shown in FIG. 7E, a positive type second photoresist film 26 is formed on the entire surface of the metal film 25.

  Next, as shown in FIG. 8A, exposure is performed using a second photomask 27 having a first transparent region 28 in a portion corresponding to the terminal electrode 2 of the electronic component 1. As a result, a second exposure region 29 is formed in the second photoresist film 26.

  A positive resist is used as the second photoresist film 26, and by making the pre-bake time shorter than the standard, a first opening 30 with a forward taper is obtained after development as shown in FIG. 8B.

  Next, as shown in FIG. 8C, the metal film 25 in the first opening 30 is removed by etching using the second photoresist film 26 as a mask. Next, development is performed using a developer for the first photoresist film 19 to form an opening 31 having a drum-shaped cross section.

  As shown in FIG. 8D, the drum-shaped protruding electrode 3 in which the granular resin 4 is dispersed and formed is formed in the drum-shaped opening 31 formed in this manner by plating or the like. Thereafter, as shown in FIG. 8E, the second photoresist film 26, the metal film 25, and the first photoresist film 19 are removed, whereby the drum-like terminal electrode 3 is formed on the terminal electrode 2. Note that the metal film 25 is formed of a material having a different etchant from the bump electrode 3.

  7 to 8 show an example in which the protruding electrodes 3 contain the granular resin 4 in a dispersed manner, but air bubbles may be dispersed and contained in place of the granular resin 4.

  Further, by increasing the thickness of the metal film 25 formed in the step shown in FIG. 7D, the protruding electrode 3 having the cylindrical constricted portion 18 shown in FIG. 6 can be easily formed.

  As a method of dispersing the granular resin in the protruding electrode, a method of dispersing an acrylic resin, styrene resin, silicon resin or the like in an electrolytic solution and performing electrolytic plating while stirring can be used.

  In addition, as a method of dispersing and containing bubbles in the protruding electrode, electrolytic plating is performed by adding a substance that generates bubbles by heating, for example, sodium bicarbonate or an organic solvent encapsulated in a resin capsule to the electrolytic solution. The method can be used. In this case, by heating after forming the bumps, the above substances can be generated or decomposed to form bubbles in the protruding electrodes.

  6 and FIG. 8, the cylindrical constricted portion 18 is shown in the substantially central portion in the height direction of the protruding electrode 3, but the position and the cross-sectional area can be changed as necessary. May be. Furthermore, the cross-sectional areas of the lower surface portion and the upper surface portion of the protruding electrode 3 may not be the same.

  That is, the height, the bottom surface area, and the constriction area of each protruding electrode should be determined in consideration of the material, shape, thickness, etc. of the electronic component and the substrate.

  Note that the material described in the first embodiment is used as the material used for each protruding electrode.

  6 to 8, the electronic component 1 shows only one terminal electrode 2 and the protruding electrode 3 formed thereon, but in general, the electronic component 1 includes a plurality of terminals. The electrode 2 is provided, and the protruding electrodes 3 are formed in accordance with the number of terminal electrodes 2.

  For example, when the electronic component 1 is a bare-chip semiconductor element or a packaged semiconductor device, it may have several tens to several hundred terminal electrodes. Even in such an electronic component 1, on the terminal electrode 2, a protruding electrode 3 having a cylindrical constricted portion 18 at the center and in which a granular resin 4 is dispersed in a metal material is formed. If it is connected to a wiring electrode (not shown) of a substrate (not shown), a highly reliable mounting configuration can be realized. That is, when a semiconductor element or a semiconductor device as described above is mounted on a substrate made of resin, the thermal expansion coefficients of the semiconductor element or semiconductor device that is the electronic component 1 and the substrate are greatly different, and a large amount of heat is generated during or during use. Stress is applied between the protruding electrode and the protruding electrode and the terminal electrode or between the protruding electrode and the wiring electrode. Furthermore, not only the thermal stress but also a stress may be applied by receiving a force from an external impact or the like. However, with the protruding electrode of the present embodiment, this stress can be absorbed by the shape having the cylindrical constricted portion and the large elastic deformation force of the composite material containing the granular resin in a dispersed manner. Therefore, it is possible to suppress the occurrence of defects at the joints and the protruding electrodes.

  In the present embodiment, the case where the connection surface 5 is the upper surface of the protruding electrode 3 has been described. However, a bonding metal layer 13 similar to that shown in FIG. 3 may be provided on the upper surface of the protruding electrode 3. .

  In the first to third embodiments, the description has been given using the example in which the protruding electrode is formed on the terminal electrode of the electronic component. However, the protruding electrode is formed on the substrate side using the same method. Can also be formed.

  The protruding electrode for connecting an electronic component according to the present invention is useful in the field of semiconductor mounting in which a large-area semiconductor element typified by a large-scale integrated circuit or an image pickup element or a package on which a semiconductor element is mounted is mounted on a substrate.

Sectional drawing of the protruding electrode for electronic component connection concerning the 1st Embodiment of this invention Process sectional drawing for demonstrating the manufacturing method of the projection electrode for electronic component connection of the embodiment Sectional drawing which shows the 1st modification of the protrusion electrode for electronic component mounting concerning the embodiment Sectional drawing of the protruding electrode for electronic component connection concerning the 2nd Embodiment of this invention Process sectional drawing for demonstrating the manufacturing method of the projection electrode for electronic component connection of the embodiment Sectional drawing of the projection electrode for electronic component connection concerning the 3rd Embodiment of this invention Process sectional drawing for demonstrating the first half process of the manufacturing method of the projection electrode for electronic component connection in the embodiment Process sectional drawing for demonstrating the latter half process of the manufacturing method of the projection electrode for electronic component connection in the embodiment Sectional drawing for demonstrating the conventional drum-like projection electrode Sectional view of bump electrode with conventional resin particles dispersed

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic component 2,42 Terminal electrode 3,43,45 Projection electrode 4 Granular resin 5 Connection surface 6 Constriction part 7 1st resist film 8,30 1st opening part 9 1st projection electrode 10 2nd resist film 11 2nd opening Part 12 Second protruding electrode 13 Bonding metal layer 14 Outline line 15 Straight line 16 Resist film 17 Drum-shaped opening 18 Tubular constriction part 19 First photoresist film 20 First photomask 21 First opaque area 22 Ultraviolet light 23 First exposure Area 24 first unexposed area 25 metal film 26 second photoresist film 27 second photomask 28 first transparent area 29 second exposed area 31 drum-shaped opening 41 semiconductor element 44 protective film 46 resin particles

Claims (10)

A protruding electrode for connecting between a terminal electrode of an electronic component and a wiring electrode of a substrate corresponding to the terminal electrode,
The protruding electrode is formed on the terminal electrode of the electronic component or the wiring electrode of the substrate, and has a cross-sectional shape provided with a constricted portion at the center, and among the granular resin and bubbles in the metal material A protruding electrode for connecting electronic parts, wherein at least one is made of a composite material dispersed. The metal material constituting the protruding electrode has a melting point higher than the temperature for bonding the terminal electrode and the wiring electrode with the protruding electrode, and retains its shape even after application of pressure for bonding. The protruding electrode for connecting an electronic component according to claim 1. The protruding electrode for connecting an electronic component according to claim 1, wherein a bonding metal layer is formed on a surface of the protruding electrode bonded to the terminal electrode or the wiring electrode. 4. The protruding electrode for connecting an electronic component according to claim 3, wherein the bonding metal layer is made of only the metal material. The protruding electrode for connecting an electronic component according to claim 3, wherein the bonding metal layer is made of a metal material having a melting point lower than that of the metal material. On the terminal electrode of the electronic component or on the wiring electrode of the substrate corresponding to the terminal electrode, it has a cross-sectional shape with a constricted portion at the center, and at least one of granular resin and bubbles is dispersed in the metal material A method for producing a protruding electrode for connecting electronic components, comprising forming a protruding electrode made of a composite material by plating. The composite material is foamed by a resin dispersion plating method in which a granular resin is dispersedly contained in a metal material or a resin dispersion plating method including a foamable resin containing a substance that generates bubbles when heated. The electronic component connection according to claim 6, wherein a method is used in which after forming a metal film containing a dispersible resin, the metal film is heated to generate bubbles from the foamable resin. For producing a protruding electrode for an automobile. A first opening having an opening area on the upper surface portion smaller than the lower surface portion contacting the terminal electrode or the wiring electrode on the terminal electrode of the electronic component or on the wiring electrode of the substrate corresponding to the terminal electrode. Forming a first resist film having a portion;
A first plating step of forming a first protruding electrode filling the first opening with the composite material;
A second resist provided with a second opening having a shape in which the surface of the first protruding electrode filled in the first opening is exposed and the upper surface of the first protruding electrode has a larger cross-sectional area than the surface of the first protruding electrode Forming a film on the first resist film;
A second plating step of forming, from the composite material, a second protruding electrode that is continuous from the first protruding electrode and fills the second opening;
The method for manufacturing a protruding electrode for connecting an electronic component according to claim 6, further comprising a step of removing the first resist film and the second resist film. Forming a resist film having a cross-sectional opening having a constricted portion at the center on the terminal electrode of the electronic component or the wiring electrode of the substrate;
A plating step of forming the protruding electrode filling the opening with the composite material;
The method for manufacturing a protruding electrode for connecting an electronic component according to claim 6, further comprising a step of removing the resist film. Applying a negative resist film on the terminal electrode of the electronic component or the wiring electrode of the substrate;
The negative resist film at a predetermined position on the terminal electrode or the wiring electrode has a shape in which the cross-sectional area of the upper surface portion is smaller than the lower surface portion in contact with the terminal electrode or the wiring electrode, and the second opening portion. Forming an unexposed portion to be selectively exposed,
Forming a light shielding film having a light shielding property on the negative resist film;
Applying a positive resist film on the light shielding film;
The positive resist film located above the unexposed portion of the negative resist film has a lower surface portion that is the same as the cross-sectional area of the upper surface portion of the unexposed portion, and the upper surface portion is a section of the lower surface portion. Forming an exposure portion that becomes a first opening with a shape larger than an area by selective exposure;
Developing the positive resist film to remove the positive resist film in the exposed portion and forming the first opening;
Etching the light shielding film exposed on the lower surface of the first opening; and
Developing the negative resist film to remove the negative resist film in the unexposed portion and forming the second opening connected to the first opening;
The method for manufacturing a protruding electrode for connecting an electronic component according to claim 6, further comprising: a plating step of forming a protruding electrode in the first opening and in the second opening with the composite material. .

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