JP5125314B2 - Electronic equipment - Google Patents

Description

The present invention relates to an electronic device, a mounting structure, and a method for manufacturing the mounting structure.

  2. Description of the Related Art Conventionally, in circuit boards and liquid crystal display devices mounted on various electronic devices, a technique for mounting an electronic component such as a semiconductor IC on the substrate is used. For example, a liquid crystal driving IC chip for driving a liquid crystal panel is mounted on the liquid crystal display device. The liquid crystal driving IC chip may be directly mounted on a glass substrate constituting the liquid crystal panel, or may be mounted on a flexible substrate (FPC) mounted on the liquid crystal panel. The former mounting structure is called a COG (Chip On Glass) structure, and the latter is called a COF (Chip On FPC) structure. In addition to these mounting structures, for example, a COB (Chip On board) structure in which an IC chip is mounted on a glass epoxy substrate or the like is also known.

  On the substrate used for such a mounting structure, lands (terminals) connected to the wiring pattern are formed, while on the electronic component, bump electrodes for obtaining electrical connection are formed (for example, Patent Document 1, Patent Document 2, and Patent Document 3). The electronic component mounting structure is formed by mounting the electronic component on the substrate in a state where the bump electrode is connected to the land.

By the way, in the mounting structure described above, it is desired that the electronic component is more firmly and securely connected on the substrate. In particular, when there are a plurality of lands and bump electrodes, and a plurality of lands and bump electrodes are connected to each other, all the lands and bump electrodes are connected well to ensure reliability. It has become important.
Japanese Patent Laid-Open No. 6-333982 Japanese Patent Laid-Open No. 9-293753 JP 2004-153139 A

However, the bump electrodes described in Patent Documents 1 to 3 are all made of metal. Therefore, when the bump electrode is similarly bonded to a land (terminal) made of metal, the bonding strength is increased. There was a risk that variations would easily occur, resulting in poor contact (conductive failure). Further, even when the bonding is performed with sufficient strength, the bonded portion may be peeled off due to a mechanical external force, thermal stress, or the like, resulting in contact failure (conductivity failure).
Note that such a poor contact between the bump electrode and the land (terminal) is the same in the mounting structure in which one substrate on which the bump electrode is formed is bonded to the other substrate on which the terminal (land) is formed. Could occur.

  The present invention has been made in view of the above circumstances, and the object thereof is a mounting structure that ensures sufficiently high bonding strength between the bump electrode and the terminal, thereby improving the reliability of electrical connection, It is another object of the present invention to provide a method for manufacturing a mounting structure.

The electronic device according to the present invention includes a bump electrode including a substrate including a terminal, a conductive film in contact with the terminal, an internal resin covered with the conductive film, and the terminal electrically connected to the terminal. A cross-section perpendicular to the surface of the bump electrode in contact with the electronic component, the electronic component connected to the electronic component, and a sealing resin that holds the conductive film and the terminal in contact with each other The position where the width along the side direction in contact with the electronic component is maximum is an intermediate portion between the substrate and the electronic component, and the sealing resin is filled around the bump electrode. It is characterized by. Further, the internal resin has a curved portion that is concave outward in the vicinity of a contact portion with the electronic component.
The mounting structure of the present invention is a mounting structure formed by mounting a mounting body having a bump electrode on a substrate having terminals,
The bump electrode has a structure in which an inner resin is used as a core and a conductive film is covered on the surface thereof. The conductive film is in direct conductive contact with the terminal, and the substrate and the mounting body include the mounting. A pressure-bonding means for holding the state in which the bump electrode is in conductive contact with the terminal in a state where the body is pressed relatively to the substrate side and the internal resin is elastically deformed;
The inner resin has a main cross-sectional shape orthogonal to a bottom surface that contacts the mounting body, and is surrounded by a bottom side that contacts the mounting body and an outer side that protrudes outside the mounting body. And, two points located at both ends of the bottom side are defined as the first point, and two points on the outer side at the position where the width along the bottom direction in the main cross section is maximized are the second point. Then, an angle formed by a straight line connecting the first point and the second point located on the same side in the main cross section and a surface of the mounting body that is in contact with the base and extends outside the base Is formed at an acute angle,
The conductive film is provided on a surface of the internal resin along a surface direction of the main cross section of the internal resin.

According to this mounting structure, since the bump electrode having the inner resin as the core is in conductive contact with the terminal in a state where the inner resin is elastically deformed, the surface thereof is caused by the elastic restoring force (repulsive force) of the inner resin. The upper conductive film is bonded to the terminal with a high strength, and thus a sufficiently high bonding strength is ensured between the bump electrode and the terminal. Therefore, the reliability of electrical connection between the bump electrode and the terminal is improved.
Further, when the crimping means is constituted by a sealing resin which is filled and cured around the conductive contact portion between the bump electrode and the terminal, the sealing resin has the acute angle on the bottom surface side of the internal resin. It enters into the part formed in and is firmly fixed here by the anchor effect. Therefore, the adhesive strength of the sealing resin to the mounting body is increased, and the pressure-bonding / holding effect of the pressure-bonding means made of the sealing resin is increased, thereby further stabilizing the mounting structure.

In the mounting structure, it is preferable that the position where the width along the bottom direction in the main cross section becomes maximum is the bottom side of the internal resin in a state before elastic deformation.
In this way, before the inner resin is elastically deformed by joining to the terminal, the bottom side in the shape of the main cross section has the maximum width. The maximum width in the main cross section shifts to the outer side and the corner becomes an acute angle, and the internal resin is sufficiently elastically deformed so that the shape on the bottom side is greatly changed. Therefore, after bonding to the terminal, the elastic restoring force (repulsive force) of the internal resin becomes larger, so that the conductive film on the surface is bonded to the terminal with high strength, and therefore the bump electrode and the terminal The bonding strength between the two becomes higher.
In addition, when the crimping means is made of a sealing resin that is filled and cured around the conductive contact portion between the bump electrode and the terminal, the conductive contact portion between the bump electrode and the terminal is cured around the conductive contact portion. When the sealing resin is filled and then the inner resin is elastically deformed as described above, the excessive sealing resin is discharged to the outside by the elastic deformation of the inner resin, and the substrate and the substrate are removed by an appropriate amount of the sealing resin. The space between the mounted body is maintained. Therefore, the mounting structure is further stabilized.

Further, in the mounting structure, the internal resin has a substantially bowl-like shape in which the cross section as the main cross section is substantially semicircular, substantially semielliptical, or substantially trapezoidal before being elastically deformed. It is preferable that the conductive film is formed in a strip shape on the surface of the internal resin along the surface direction of the main cross section of the internal resin.
In this way, by providing a plurality of conductive films at intervals on the surface of the internal resin, a plurality of bump electrodes can be formed, which facilitates manufacture.

In the mounting structure, it is preferable that the pressure-bonding means is formed of a sealing resin that is filled and cured around a conductive contact portion between the bump electrode and the terminal.
In this way, the conductive contact state between the elastically deformed bump electrode and the terminal is better maintained, and the conductive connection state between the conductive film of the bump electrode and the terminal becomes better.
Further, as described above, by entering the portion formed at the acute angle on the bottom surface side of the internal resin and firmly fixing here by the anchor effect, the adhesion strength of the sealing resin to the mounting body is increased. The pressure-bonding / holding effect of the pressure-bonding means made of the sealing resin is enhanced, and the mounting structure is further stabilized.
In addition, as described above, excessive sealing resin is discharged to the outside due to elastic deformation of the internal resin, and an appropriate amount of sealing resin holds between the substrate and the mounting body. The mounting structure becomes more stable.

In the mounting structure, it is preferable that the inner resin has a curved portion in which the outer side in the main cross section is recessed outward in the vicinity of the bottom side.
In this way, the corner formed between the outer side of the inner resin and the mounting body becomes a curved portion without being formed at an acute angle, so stress concentration at this corner is reduced. It is alleviated and disconnection of the conductive film provided on this corner due to stress concentration is prevented.
Further, in the mounting structure, the mounting body may be an electronic component.
By using the mounting body as an electronic component, it is possible to obtain a good mounting structure for an electronic component in which a sufficiently high bonding strength is ensured between the bump electrode and the terminal.

Further, the mounting structure manufacturing method of the present invention is a mounting structure manufacturing method in which a mounting body having bump electrodes is mounted on a substrate having terminals,
A bump electrode forming step of forming an internal resin to be a core on the mounting body, covering the surface with a conductive film, and forming a bump electrode;
A mounting step of mounting the mounting body on the substrate in a state in which the conductive film of the bump electrode is in direct conductive contact with the terminal of the substrate;
A crimping step of pressing the mounting body relative to the substrate side and holding the state in a state where the bump electrode is in conductive contact with the terminal; and
The bump electrode forming step includes
The shape of the main cross section of the cross section orthogonal to the bottom surface in contact with the mounting body for the internal resin to be the core is defined by the bottom side in contact with the mounting body and the outer side protruding outside the mounting body. Two points that are enclosed and located at both ends of the base are defined as the first point, and two points on the outer side at the position where the width along the base direction in the main cross section is maximum are the second points. The internal resin forming step of forming the conductive film so that the position where the width along the bottom direction in the main cross section in the main cross section becomes the maximum is the base, and the conductive film is formed on the main cross section of the internal resin. A conductive film forming step provided on the surface of the internal resin along the surface direction,
The crimping process includes
By relatively pressing the mounting body toward the substrate side in a state where the bump electrode is in conductive contact with the terminal, the internal resin is placed on the same side in the main cross section and the first point. A pressurizing step of elastically deforming an angle formed by a straight line connecting the second point and a surface of the mounting body that is in contact with the base and extends outside the base; And a holding step for holding the state of the internal resin that has been elastically deformed.

  According to the method for manufacturing the mounting structure, the internal resin in the bump electrode is formed such that the position where the width along the bottom direction in the main cross section is the maximum is the base, and then the bump electrode is formed. The inner resin is elastically deformed so that the corner becomes an acute angle by relatively pressing the mounting body toward the substrate side in a conductive contact state with the terminal. The shape is sufficiently elastically deformed to change greatly. Therefore, after bonding to the terminal, the elastic restoring force (repulsive force) of the internal resin becomes larger, so that the conductive film on the surface is bonded to the terminal with high strength, and therefore the bump electrode and the terminal The bonding strength between the two becomes higher. Therefore, a sufficiently high bonding strength can be ensured between the bump electrode and the terminal, and the reliability of the electrical connection between the bump electrode and the terminal can be improved.

In the mounting structure manufacturing method, in the holding step, the inner resin is elastically deformed by curing a sealing resin disposed around a conductive contact portion between the bump electrode and the terminal. It is preferable to maintain the state.
In this way, the conductive contact state between the elastically deformed bump electrode and the terminal can be kept better, and the conductive connection state between the conductive film of the bump electrode and the terminal can be made better. it can.
Further, since the sealing resin enters the portion formed at the acute angle on the bottom surface side of the internal resin and is firmly fixed thereto by an anchor effect, the adhesion strength of the sealing resin to the mounting body is increased. The mounting structure can be further stabilized by increasing the pressure-bonding / holding effect of the pressure-bonding means made of the sealing resin.
Further, if the sealing resin before curing is filled in advance around the conductive contact portion between the bump electrode and the terminal, and then the internal resin is elastically deformed and the sealing resin is cured in that state, the internal resin Excessive sealing resin can be discharged to the outside by elastic deformation of this, and then an appropriate amount of sealing resin can be cured, so that the space between the substrate and the mounting body can be held well. Therefore, the mounting structure can be further stabilized.

In the mounting structure manufacturing method, in the inner resin forming step, the inner resin is formed in a substantially semicircular shape, a substantially semi-elliptical shape, or a substantially trapezoidal shape in which the transverse cross section that is the main cross section is a substantially semicircular shape. In the conductive film forming step, it is preferably provided in a strip shape on the surface of the internal resin along the surface direction of the main cross section of the internal resin.
In this way, by providing a plurality of conductive films at intervals on the surface of the internal resin, a plurality of bump electrodes can be formed, which facilitates manufacture.

Hereinafter, the mounting structure of the present invention will be described in detail.
FIG. 1 is a schematic view showing a liquid crystal display device to which a mounting structure according to the present invention is applied. First, an application example of the mounting structure according to the present invention will be described with reference to FIG.
In FIG. 1, reference numeral 100 denotes a liquid crystal display device. The liquid crystal display device 100 includes a liquid crystal panel 110 and an electronic component (IC chip for liquid crystal drive) 121. Although not shown, the liquid crystal display device 100 is appropriately provided with incidental members such as a polarizing plate, a reflective sheet, and a backlight as necessary.

  The liquid crystal panel 110 includes substrates 111 and 112 made of glass or synthetic resin. The substrate 111 and the substrate 112 are disposed to face each other and are bonded to each other by a seal material (not shown). A liquid crystal (not shown) that is an electro-optical material is sealed between the substrate 111 and the substrate 112. An electrode 111a made of a transparent conductive material such as ITO (Indium Tin Oxide) is formed on the inner surface of the substrate 111, and an electrode 112a is formed on the inner surface of the substrate 112 so as to face the electrode 111a.

  The electrode 111a is connected to the wiring 111b integrally formed of the same material, and is drawn out on the inner surface of the substrate extension portion 111T provided on the substrate 111. The substrate overhanging portion 111T is a portion that protrudes outward from the outer shape of the substrate 112 at the end of the substrate 111. One end of the wiring 111b is a terminal 111bx. The electrode 112a is also connected to the wiring 112b integrally formed of the same material, and is conductively connected to the wiring 111c on the substrate 111 through a vertical conduction portion (not shown). The wiring 111c is also formed of ITO. The wiring 111c is drawn out on the substrate overhanging portion 111T, and one end thereof is a terminal 111cx. An input wiring 111d is formed in the vicinity of the edge of the substrate overhanging portion 111T, and one end thereof is a terminal 111dx. The terminal 111dx is disposed opposite to the terminals 111bx and 111cx. The other end of the input wiring 111d is an input terminal 111dy.

  An electronic component 121 serving as a mounting body of the present invention is mounted on the substrate extension portion 111T via a sealing resin 122 made of a thermosetting resin. The electronic component 121 is, for example, a liquid crystal driving IC chip that drives the liquid crystal panel 110. A large number of bump electrodes (not shown) according to the present invention are formed on the lower surface of the electronic component 121, and these bump electrodes are conductively connected to the terminals 111bx, 111cx, and 111dx on the substrate extension portion 111T, respectively. Has been. Thereby, the mounting structure of the present invention in which the electronic component (mounting body) 121 is mounted on the substrate 111 is formed. The sealing resin 122 is preferably an epoxy resin, an acrylic resin, or a phenol resin, but may be a resin, and the type of resin is not limited thereto.

  In addition, a flexible wiring substrate 123 is mounted on the array region of the input terminals 111dy on the substrate extension 111T via an anisotropic conductive film 124. The input terminal 111 dy is conductively connected to wiring (not shown) corresponding to each of the input terminals 111 dy provided on the flexible wiring board 123. A control signal, a video signal, a power supply potential, and the like are supplied to the input terminal 111dy from the outside via the flexible wiring board 123. A control signal, a video signal, a power supply potential, and the like supplied to the input terminal 111dy are input to the electronic component 121, where a drive signal for driving the liquid crystal is generated and supplied to the liquid crystal panel 110.

  According to the liquid crystal display device 100 configured as described above, when an appropriate voltage is applied between the electrode 111a and the electrode 112a via the electronic component 121, the both electrodes 111a and 112a are arranged to face each other. The light can be modulated independently for each pixel included in the portion, whereby a desired image can be formed in the display area of the liquid crystal panel 110.

Next, an embodiment of the mounting structure of the present invention applied to the liquid crystal display device 100 will be described.
FIG. 2A is an enlarged perspective view of a main part showing an enlarged mounting structure of the electronic component (mounting body) 121 in the liquid crystal display device 100, and FIG. 2B is a perspective view of FIG. It is AA arrow sectional drawing. 2A and 2B, reference numeral 11P represents a wiring pattern provided on the substrate 111, that is, one of the wirings 111b, 111c, and 111d, and reference numeral 11 represents a terminal provided on these wirings. That is, it represents one of the terminals 111bx, 111cx, and 111dx. Further, in FIG. 2B, reference numeral 10 indicates a mounting structure according to an embodiment of the present invention.

  In the present embodiment, the terminal 11 functions as the terminal 11 as it is, as a land (not shown) formed continuously at the end of the wiring pattern 11P, or the end of the wiring pattern 11P. Reference numeral 12 denotes a bump electrode provided on the electronic component 121. Although not shown in FIG. 2A, at least a conductive contact portion between the bump electrode 12 and the terminal 11 is provided between the substrate 111 and the electronic component 121 as shown in FIG. Covering the periphery, the sealing resin 122 serving as the pressure-bonding means in the present invention is filled and arranged and cured.

  The bump electrode 12 has a structure in which the internal resin 13 provided on the electronic component 121 is a core (core part) and the surface thereof is covered with a conductive film 14 as shown in a perspective view of a main part in FIG. have. In the present embodiment, as shown in FIG. 3A, the electronic component 121 is mounted on the substrate 111, that is, before being elastically deformed in a non-pressurized state before being bonded to the terminal 11. Then, the internal resin 13 of the bump electrode 12 is substantially bowl-shaped.

  As shown in FIG. 3B, which is a cross-sectional view taken along the line BB in FIG. 3A, the conductive film 14 is a protective film that is a constituent element of the electronic component 121. As shown in FIG. 3A, the electrode is exposed to the electrode 16 exposed in the opening of the protective film 15, and is drawn around the internal resin 13 (on the surface). Is. The conductive film 14 covering the surface of the internal resin 13 with such a configuration is electrically connected to the electrode 16, and thus substantially functions as an electrode of the electronic component 121. In the present embodiment, a plurality of strip-like conductive films 14 are provided on the surface of the internal resin 13, and these conductive films 14 are connected and electrically connected to the electrodes 16 of the electronic component 121, respectively. Therefore, each of these conductive films 14 functions independently as the bump electrode 12 in the present invention together with the internal resin 13 located inside thereof.

  Here, the substantially bowl shape of the internal resin 13 refers to a columnar shape in which the inner surface (bottom surface) in contact with the electronic component 121 is a flat surface and the outer surface side not in contact with the surface is a curved surface. Specifically, as shown in FIG. 3 (b), it is preferable that the cross section (cross section) has a substantially semicircular shape (or a substantially semielliptical shape). Is also preferred. This transverse section is the main section of the internal resin 13 in the present invention. The main cross section of the internal resin 13 in the present invention is a characteristic surface of the cross section orthogonal to the bottom surface that contacts the electronic component (mounting body) 121, and the internal resin 13 as in the present embodiment. Is substantially saddle-shaped, the transverse cross section in the width direction is the main cross section. And in the bump electrode 12 in this invention, the electrically conductive film 14 is provided on the surface of the said internal resin 13 along the surface direction of the said main cross section.

In this embodiment, the substantially semicircular shape in the main cross section (transverse cross section) of the internal resin 13 is surrounded by the bottom side 13 a that contacts the electronic component 121 and the outer side 13 b that protrudes outside the electronic component 121. Is formed.
The internal resin 13 is made of a photosensitive insulating resin or a thermosetting insulating resin, and specifically, is formed of a polyimide resin, an acrylic resin, a phenol resin, a silicone resin, a silicone-modified polyimide resin, an epoxy resin, or the like. It has been done. The internal resin 13 made of such a resin is formed in the above-described substantially bowl shape by a known lithography technique or reflow technique as described later. The material (hardness) of the resin and the shape (height and width) in details about the bowl shape are appropriately selected and designed according to the shape and size of the terminal 11 to be joined.

  The conductive film 14 is made of a metal or alloy such as Au, TiW, Cu, Cr, Ni, Ti, W, NiV, Al, Pd, or lead-free solder, and even if it is a single layer of these metals (alloys). In addition, a plurality of types may be laminated. Further, such a conductive film 14 may be formed by a known film formation method such as a sputtering method and then patterned into a band shape, or may be formed selectively by electroless plating. Good. Alternatively, a base film may be formed by sputtering or electroless plating, and then an upper layer film may be formed on the base film by electrolytic plating, and the conductive film 14 may be formed by a laminated film including the base film and the upper layer film. Good. Note that the type, layer structure, film thickness, width, and the like of the metal (alloy) are appropriately selected and designed according to the shape and size of the terminal 11 as in the case of the internal resin 13. However, since the conductive film 14 is elastically deformed together with the internal resin 13 by being bonded to the terminal 11 as described later, it is preferable to use gold (Au) having particularly excellent spreadability. Further, when the conductive film 14 is formed of a laminated film, it is preferable to use gold for the outermost layer. Furthermore, the width of the conductive film 14 is preferably formed sufficiently wider than the width of the terminal 11 to be joined.

  In the bump electrode 12 having such a structure, since the conductive film 14 is provided on the surface of the internal resin 13 along the surface direction of the main cross section, the shape of the outer side 13b of the internal resin 13, that is, It is provided along a curved shape consisting of a substantially arc-shaped curve. Therefore, since local stress concentration is less likely to occur in the conductive film 14, the conductive film 14 is prevented from being disconnected due to the stress concentration.

  Further, the electronic component 121 having the bump electrode 12 having such a structure has a structure in which the conductive film 14 of the bump electrode 12 is in direct conductive contact with the terminal 11 of the substrate 111 as shown in FIG. In addition, the electronic component 121 and the substrate 111 are pressurized and pressure-bonded with the bump electrode 12 in conductive contact with the terminal 11 as described above. Then, the sealing resin 122 filled and disposed between the substrate 111 and the electronic component 121 is cured, and thereby the state in which the bump electrode 12 is in conductive contact with the terminal 11 is maintained.

  Then, in the mounting structure 10 formed in this way, the internal resin 13 in the bump electrode 12 is pressurized as shown in FIG. 4A showing the main cross section (transverse cross section) of the bump electrode 12. It changes from the state which was not elastically deformed before to the state which was pressurized and elastically deformed similarly as shown in FIG.4 (b). In other words, in a state where the elastic plate is not elastically deformed, if two points located at both ends of the bottom side 13a are first points 30 and 30 as shown in FIG. The position where the width along the line is the maximum is the bottom side 13a, that is, the width D1 between the first points 30 and 30. Moreover, in the state which is not elastically deformed in this way, the height of the internal resin 13 is the height indicated by H1 in FIG.

  On the other hand, when the internal resin 13 is elastically deformed by being pressurized, the shape of the main cross section changes from a substantially semicircular shape to a substantially oval shape (substantially track shape) as shown in FIG. The maximum width also moves from the width D1 of the base 13a to an intermediate portion in the height direction (thickness direction) of the internal resin 13. That is, if two points on the outer side 13b at the position where the width along the base 13a direction in the main cross section is the maximum are the second points 31, 31, the maximum width in the main cross section is The width D2 between the two points 31, 31. Further, in such an elastically deformed state, the height of the internal resin 13 is the height indicated by H2 in FIG. 4B and is lower than the height indicated by H1 in FIG. . That is, the internal resin 13 is compressed and deformed.

In the state of compression deformation (elastic deformation) in this way, the internal resin 13 has a first point 30 and a second point 31 located on the same side in the main cross section as shown in FIG. The angle θ formed by the straight line L connecting the two and the surface S of the electronic component 121 that is in contact with the bottom side 13a and extends outside the base side 13a is formed as an acute angle.
Therefore, as shown in FIG. 2B, when the sealing resin 122 is filled and cured around the conductive contact portion between the bump electrode 12 and the terminal 11, the sealing resin 122 becomes the internal resin. It enters the portion of the angle θ that is an acute angle of 13 and is firmly fixed here by the anchor effect.
Further, if the sealing resin 122 before curing is filled around the conductive contact portion between the bump electrode 12 and the terminal 11, and then the internal resin 13 is elastically deformed (compressed) as described above, the internal resin is obtained. Due to the elastic deformation, excessive sealing resin 122 is discharged to the outside, and the gap between the substrate 111 and the electronic component 121 is held by an appropriate amount of sealing resin.

  Further, before the inner resin 13 is joined to the terminal 11 and elastically deformed, the base 13a in the shape of the main cross section has the maximum width D1, whereas after the inner resin 13 is joined to the terminal 11 and elastically deformed. The maximum width D2 shifts to the outer side 13b side, the angle θ becomes an acute angle, and the internal resin 13 is sufficiently elastically deformed (compressed) so that the shape of the bottom surface side changes greatly. Therefore, after the bonding to the terminal 11, the elastic restoring force (repulsive force) of the internal resin 13 becomes larger, whereby the conductive film 14 on the surface is bonded to the terminal 11 with high strength. Therefore, the bonding strength between the bump electrode 12 and the terminal 11 is higher.

4B, in the internal resin 13 in a state of being compressed and deformed (elastically deformed), when viewed microscopically, the outer side 13b in the main cross section is an outer side in the vicinity of the base 13a. A curved portion that is concave is formed. That is, as shown in FIG. 4C, which is an enlarged view of the main part of FIG. 4B, a concave portion is formed on the outer side 13b in the vicinity of the first point 30 (that is, in the vicinity of the bottom side 13a). A curved portion 13c is formed. This is because the base 13a is integrally fixed on the electronic component 121 (the protective film 15), and therefore, when the internal resin 13 is elastically deformed, the central portion of the outer side 13b bulges outward so that the base In the vicinity of 13a, an inward force is generated, which is a recess formed by this.
When the bending portion 13c is formed in this way, the corner portion formed between the outer side 13b and the electronic component 121 is not formed into an acute angle, but is curved gently and microscopically. It becomes the curved part 13c. As a result, the stress concentration at the corner is relaxed, and therefore, disconnection of the conductive film 14 provided on the corner (curved portion 13c) due to the stress concentration is prevented. ing.

Next, based on the manufacturing method of the mounting structure 10 of such a configuration, an embodiment of the manufacturing method of the present invention will be described.
First, the formation process of the bump electrode 12 which is a main configuration in the manufacturing method of the present invention will be described.
In this bump electrode 12 forming step, first, as shown in FIG. 5A, on the active surface of the electronic component 121, a resin for forming the internal resin 13, for example, a polyimide resin to be a negative resist is formed, for example, 10 to 20 μm. Apply to a certain thickness. Here, a protective film 15 made of an insulating material is formed in advance on the active surface of the electronic component 121, and an opening 15a is formed in the protective film 15 so that the electrode 16 is exposed in the opening 15a. Keep it. Then, the resin layer 130 is formed by pre-baking the applied forming resin.

  Next, as shown in FIG. 5B, the photomask 20 is positioned at a predetermined position on the resin layer 130 and set. The photomask 20 is made of a glass plate on which a light shielding film such as Cr is formed, for example, and has a rectangular opening 21 corresponding to the planar shape of the substantially bowl-shaped internal resin 13 to be formed. The positioning of the photomask 20 is performed so that the opening 21 is located at the location where the internal resin 13 is formed. Moreover, about the photomask 20, the description about a glass plate is abbreviate | omitted, and only the light shielding film is described and this is made into the code | symbol 20. FIG.

Next, the photomask 20 is irradiated with exposure light to expose the resin layer 130 exposed in the opening 21. However, in this exposure, the pattern of the resin layer 130 obtained after development is adjusted by adjusting the exposure conditions so that the cross section (main cross section) has a substantially semicircular shape (or a substantially semielliptical shape). Pattern.
Specifically, the exposure light is irradiated obliquely as shown by an arrow in FIG. 5B, and the exposed portion of the resin layer 130 has a substantially semicircular cross section as shown by a broken line in FIG. 5B. (Substantially trapezoidal). Further, as shown in FIG. 5C, off-contact exposure is performed in which the photomask 20 is exposed while being separated from the resin layer 130, and a portion to be exposed in the resin layer 130 is indicated by a broken line in FIG. Thus, it is good also as a cross section substantially semicircle shape (substantially trapezoid shape). Further, a semi-transmissive half mask may be used as the photomask 20, and the exposed portion may have a substantially semicircular shape (substantially trapezoidal shape) as described above. As the half mask, the peripheral portion of the opening 21 is made semi-transparent, and the translucency gradually decreases as the distance from the opening 21 increases. By forming the semi-transmissive region in this way, it is possible to perform exposure of the outer side portion, that is, the side portion in the substantially semicircular shape (substantially trapezoidal shape).

  When exposure is performed in this manner, the entire region of the resin layer 130 exposed in the opening 21 of the mask 20 is exposed in the thickness direction. Further, in the peripheral portion of the opening 21, the exposure amount gradually decreases as the distance from the opening 21 increases. Therefore, after the exposure process is performed in this manner, when the development process is performed, the unexposed portion of the resin layer 130 is developed and removed. On the other hand, the exposed portion in the opening 21 which is an exposed portion remains as it is without being developed. In addition, the bottom surface side remains in the peripheral portion according to the exposure amount. As a result, as shown in FIG. 5D, a resin pattern 130a having a substantially trapezoidal cross section and a substantially bowl shape is obtained.

  About the resin pattern 130a obtained, the shape can be adjusted to some extent by exposure conditions and development conditions. Therefore, the shoulder portion 130b of the resin pattern 130a can be curved to some extent as shown in FIG. 5D by adjusting the semi-transmissive region of the half mask. However, it is preferable to perform a reflow process in order to curve the shoulder portion 130b more gently and further curve the side portion and the upper side portion so that the entire exposed surface has a curved (curved) shape.

  The reflow process is performed by heating to a temperature at which the resin softens and the surface melts according to the material of the resin pattern 130a. After being heated and melted in this manner, the internal resin 13 having a substantially semicircular main cross section is obtained as shown in FIG. That is, the resin pattern 130a becomes a continuous curved surface whose surface is gently curved as a whole in the process of softening / melting and solidifying the surface by the reflow process. Speaking of the cross section (main cross section) formed in a substantially semicircular shape (substantially trapezoidal shape), the entire outer side 13b is a continuous and gently curved line, which is closer to a semicircle. That is, when the resin is softened and the surface is melted, the outer side 13b has a shape closer to a semicircle by dripping both sides (both shoulder portions) by its own weight as shown in FIG. 6 (a). . Thereby, the internal resin formation process in a bump electrode formation process is complete | finished.

When the internal resin 13 according to the present invention is thus formed, the above-described metal (alloy) such as Au is formed on the entire surface of the substrate 111 by sputtering (sputtering) or the like as shown in FIG. 6B. Then, a film is formed to form the conductive layer 14a.
Next, a resist pattern (not shown) is formed on the conductive layer 14a by a known resist technique or lithography technique, and the conductive layer 14a is etched using the resist pattern as a mask, thereby obtaining the structure shown in FIG. A conductive film 14 having a predetermined pattern is formed. Thereby, the conductive film formation process in the bump electrode formation process is completed. As the etching, any method such as dry etching using plasma or wet etching using a chemical solution can be employed.

Thereafter, the resist pattern is removed. Thereby, the formation process of the bump electrode 12 is completed.
In particular, when the internal resin 13 is formed, a cross section (main cross section) is obtained by combining half exposure for adjusting the exposure amount for the resin layer 130 and reflow treatment for the developed resin pattern 130a as described above. ) Is formed in a substantially semicircular shape (substantially semi-elliptical shape), but as described above, a desired shape may be formed only by half exposure, or a desired shape may be formed only by reflow processing. .

  After the bump electrode 12 is formed on the electronic component 121 in this manner, a mounting process for mounting the electronic component 121 on the substrate 111 is subsequently performed. First, as shown in FIG. 7A, the electronic component 121 is positioned with respect to the substrate 111 so that the bump electrodes 12 and the terminals 11 face each other. Then, in this state, as shown in FIG. 7B, pressurization is performed in the direction in which the bump electrodes 12 are bonded to each other, whereby the conductive film 14 of the bump electrode 12 is bonded to the terminal 11 and is brought into conductive contact. This completes the mounting process.

  When the mounting process is performed in this manner, the electronic component 121 is relatively pressed toward the substrate 111 while the conductive film 14 and the terminal 11 are in conductive contact with each other, as shown in FIG. Thus, the internal resin 13 is elastically deformed (compressed) into a desired shape. That is, the shape of the main cross-section that was substantially semicircular before deformation is compressed and deformed until it becomes substantially oval. When compressed and deformed in this way, as shown in FIG. 4B, the angle formed by the straight line L connecting the first point 30 and the second point 31 and the surface S extending outside the base 13a. θ becomes an acute angle.

  Here, the range of the acute angle of the angle θ formed by compressive deformation is not particularly limited, but is preferably 20 ° or more and 70 ° or less. By setting the angle to 20 ° or more, pressurization when compressing and deforming the internal resin 13 can be performed in a normal pressure range without being excessively high, and pressurization with excessive pressure causes damage to the electronic component 121 and the like. This is because there is no risk of giving. Further, by setting the angle to 70 ° or less, a sufficient degree of compressive deformation can be secured, and a sufficient elastic restoring force (repulsive force) can be obtained accordingly.

  When the pressurizing step is performed in this manner, this pressurized state is maintained, and thus the inner resin is kept compressed and deformed as shown in FIG. The sealing resin 122 is filled between the substrate 111 and the electronic component 121 and cured. As a result, even when the pressurized state is returned to the non-pressurized state, the state in which the internal resin is compressed and deformed is held by the sealing resin 122. Thereby, the mounting structure 10 of the present invention is obtained by completing the holding process and further completing the crimping process.

Here, the sealing resin 122 as the pressure bonding means is provided in an uncured state between the substrate 111 and the electronic component 121 in advance, the conductive film 14 and the terminal 11 are brought into conductive contact, and further pressurized to the inside. The resin 13 may be cured after being compressed and deformed into a desired shape. In that case, excessive sealing resin 122 is discharged to the outside due to compression deformation of the internal resin 13, and the gap between the substrate 111 and the electronic component 121 is held by an appropriate amount of sealing resin 122. Further, since the uncured sealing resin 122 has a certain degree of fluidity, when the internal resin 13 is compressed and deformed into a desired shape, the uncured sealing resin 122 is compressed and deformed by the internal resin 13. Along with this, the internal resin 13 easily enters the acute angle portion of the internal resin 13 and is filled therein.
The sealing resin 122 is filled in an uncured state between the substrate 111 and the electronic component 121 after the conductive film 14 and the terminal 11 are brought into conductive contact and the internal resin 13 is compressed and deformed. Then, it may be cured. In that case, the uncured sealing resin 122 enters the portion of the acute angle θ of the internal resin 13 formed by compressive deformation well, and is filled therein.

  According to such a manufacturing method, the internal resin 13 in the bump electrode 12 is formed so that the maximum width in the main cross section becomes the base 13a, and then the bump electrode 12 is in conductive contact with the terminal 11. By pressing the electronic component 121 relatively toward the substrate 111 side, the internal resin 13 is compressed and deformed (elastically deformed) so that the angle θ becomes an acute angle. The greater the change, the more sufficiently the compression deformation (elastic deformation). Therefore, after the bonding to the terminal 11, the elastic restoring force (repulsive force) of the internal resin 13 becomes larger, so that the conductive film 14 on the surface is bonded to the terminal 11 with high strength. Therefore, the bonding strength between the bump electrode 12 and the terminal 11 becomes higher. Therefore, a sufficiently high bonding strength can be ensured between the bump electrode 12 and the terminal 11, and the reliability of the electrical connection between the bump electrode 12 and the terminal 11 can be improved.

  Moreover, in the mounting structure 10 obtained in this way, the internal resin 13 is sufficiently compressed and deformed (elastically deformed) as described above, so that the elastic restoring force (repulsive force) becomes larger. As a result, the conductive film 14 on the surface is bonded to the terminal 11 with high strength, and therefore the bonding strength between the bump electrode 12 and the terminal 11 is higher. Therefore, a sufficiently high bonding strength is ensured between the bump electrode 12 and the terminal 11, and the reliability of the electrical connection between the bump electrode 12 and the terminal 11 is improved.

Further, since the sealing resin 122 is filled and cured around the conductive contact portion between the bump electrode 12 and the terminal 11, the sealing resin 122 has an acute angle θ of the internal resin 13. It enters the part of and becomes firmly fixed here by the anchor effect. Therefore, the adhesive strength of the sealing resin 122 to the electronic component 121 is increased, and the pressure-bonding / holding effect of the pressure-bonding means made of the sealing resin 122 is increased, and the mounting structure is further stabilized.
Further, if the sealing resin 122 before curing is filled around the conductive contact portion between the bump electrode 12 and the terminal 11, and then the internal resin 13 is elastically deformed (compressed) as described above, the internal resin is obtained. Due to the elastic deformation, excessive sealing resin 122 is discharged to the outside, and the gap between the substrate 111 and the electronic component 121 is held by an appropriate amount of sealing resin. Therefore, the mounting structure becomes more stable.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, as the structure of the bump electrode, the internal resin is not formed in a substantially bowl shape as shown in FIGS. 2A and 3A, and no pressure is applied before being compressed and deformed. In this state, as shown in FIG. 8, the internal resin 17 is formed in a substantially hemispherical shape, and the conductive film 18 is provided in a state of covering the entire upper surface of the internal resin 17 and conducting to the electrode 16 of the electronic component. The structure may be different.

Moreover, in the said embodiment, although the electronic component was used as the mounting body of this invention, therefore, the mounting structure of this invention was applied to the mounting structure of an electronic component, For example, a board | substrate can also be used as a mounting body. . That is, for example, as shown in FIG. 9, the bump electrode 12 is formed on the back surface side of the substrate 41 on which the electronic component 40 is mounted on the front surface side, the substrate 41 is mounted on another substrate 42, and the The bump electrode 12 may be bonded to the terminal 11 of the substrate 42 to make conductive contact.
Even in such a mounting structure, since the elastic restoring force (repulsive force) of the internal resin of the bump electrode 12 is large, the bonding strength between the bump electrode 12 and the terminal 11 becomes higher. A sufficiently high bonding strength is ensured between the bump electrode 12 and the terminal 11, and the reliability of the electrical connection between the bump electrode 12 and the terminal 11 is improved.

Moreover, in the said embodiment, although sealing resin 122 is used as a crimping | compression-bonding means in this invention, a board | substrate is used as a mounting body as mentioned above, for example, Therefore This invention is applied to the mounting structure between a board | substrate. In such a case, the crimping means of the present invention may be constituted by various mechanical crimping means. Specifically, as shown in FIG. 10 (a), a clip 50 may be used to press-bond between the substrates 41 and 42 from the outside, and a screw 51 may be used as shown in FIG. 10 (b). 41 and 42 may be crimped from the outside.
Further, even when an adhesive (resin) is used as the crimping means, for example, only between the outer peripheral portion of the electronic component and the substrate without being filled around the conductive contact portion between the bump electrode 12 and the terminal 11. Alternatively, it may be arranged selectively.

In addition to the substrate made of glass or synthetic resin, various substrates such as a rigid substrate, a silicon substrate, and a thin ceramic substrate can be used as the substrate 111. In addition to the IC chip for driving the liquid crystal, the electronic component has various ICs and connection electrodes (bump electrodes) as described above, such as passive components such as diodes, transistors, light emitting diodes, laser diodes, oscillators and capacitors. Any electronic component can be used.
In addition, the device to which the electronic component mounting structure of the present invention is applied is not limited to the above-described liquid crystal display device, but also an organic electroluminescence device (organic EL device), a plasma display device, an electrophoretic display device, and an electron emission device. The present invention is applicable to various electro-optical devices and various electronic modules such as devices using elements (Field Emission Display, Surface-Conduction Electron-Emitter Display, etc.).

It is a schematic perspective view which shows typically the structure of the liquid crystal display device to which this invention was applied. (A) and (b) are the principal part enlarged views of the mounting structure which concerns on this invention. (A) (b) is a schematic block diagram of the bump electrode before joining to a terminal. (A)-(c) is a figure which shows the main cross-sectional shape before and behind the elastic deformation of internal resin. (A)-(d) is a sectional side view for demonstrating the formation process of a bump electrode. (A) and (b) are sectional side views for demonstrating the formation process of a bump electrode. (A)-(d) is a figure for demonstrating the manufacturing method of a mounting structure. It is a perspective view which shows schematic structure of a bump electrode. It is principal part side sectional drawing which shows other embodiment of the mounting structure which concerns on this invention. (A) (b) is principal part side sectional drawing which shows the example using a mechanical crimping | compression-bonding means.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Mounting structure, 11 ... Terminal, 11P ... Wiring pattern, 12 ... Bump electrode, 13, 17 ... Internal resin, 13a ... Bottom side, 13b ... Outer side, 14, 18 ... Conductive film, 30 ... 1st point, 31 ... Second point, 100 ... Liquid crystal display device, 110 ... Liquid crystal panel, 111 ... Substrate, 111a, 112a ... Electrode, 111b, 112b, 111c ... Wiring, 111d ... Input wiring, 111bx, 111cx, 111dx ... Terminal, 121 ... Electronic components (mounting body), 122 ... Sealing resin (crimping means), 130 ... Resin layer

Claims (1)

A substrate with terminals;
A bump electrode comprising a conductive film in contact with the terminal, an internal resin covered with the conductive film;
An electronic component electrically connected to the terminal via the bump electrode;
A sealing resin filled around the bump electrode and holding the conductive film and the terminal in contact with each other;
In a state where the bump electrode is pressurized and elastically deformed,
In the cross section perpendicular to the surface of the bump electrode in contact with the electronic component, the position where the width along the side direction in contact with the electronic component is maximum is an intermediate portion between the substrate and the electronic component,
The electronic device according to claim 1, wherein the internal resin has a curved portion that is recessed outward in the vicinity of a contact portion with the electronic component.

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