JP2003031613A - Flip chip mounting body and method of mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flip chip mounting body and a method of mounting the same flip chip to realize easier management of a gap between a chip and circuit substrate and also stable electrical connection between the chip and circuit substrate. SOLUTION: The flip chip mounting body comprises the circuit substrate 4 including a conductive part 5 and the chip 1 including a solder part 3, in which the conductive part 5 and solder part 3 are provided opposed to each other and are electrically connected. The conductive part 5 is formed as projected electrodes 5a to 5g in which at least a part thereof enters the solder part 5 of the chip 1 to realize electrical connection between the circuit substrate 4 and chip 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip chip mounting body and a flip chip mounting method for fixing a chip on a circuit board provided with a predetermined conductive portion and electrically connecting the chip and the circuit board. is there.

[0002]

2. Description of the Related Art As a conventional flip-chip mounting body and its flip-chip mounting method, as shown in FIG. 8, for example, a soldering portion 3 provided on the mounting surface side of a chip 1 and a conductive portion provided on the circuit board 4 side are provided. An apparatus and a method connected to No. 5 can be mentioned.

First, as shown in FIG.
Is provided with an electrode pad 2 made of, for example, Al, and a solder bump, for example, is formed as a solder portion 3 on the electrode pad 2. In addition, for example, a board electrode is previously formed as the conductive portion 5 on the circuit board 4. Then, as shown in FIG. 8A, the flux 7 is transferred to the solder bump.

Next, as shown in FIG. 8B, the solder bumps are melted by heating, and after flux cleaning, a sealing resin 6 such as a thermosetting epoxy resin is placed in the gap between the chip 1 and the circuit board 4. It is injected and cured by heat treatment to obtain a flip chip mounting body as shown in FIG.

[0005]

However, in the flip chip mounting method as described above, since the solder portions are completely melted, the shape of each solder portion is unlikely to be constant, and the gap between the chip and the circuit board is small. However, there is a problem that it is difficult to accurately manage.

Further, the reason why the flux cleaning step of cleaning and removing the residual flux is carried out is that the flux remaining in the solder portion lowers the connection reliability, but this complicates the process and increases the number of defective products. However, there is a problem in that a running cost is required to maintain the process. Further, since the surface of the solder portion is easily oxidized, there is a problem that stable electrical connection between the chip and the circuit board may not be possible.

The present invention has been made to solve the above problems, and facilitates management of the gap between the chip and the circuit board, and realizes a stable electrical connection between the chip and the circuit board. An object of the present invention is to provide a mounting body and a flip chip mounting method.

[0008]

A chip mounting body according to claim 1 has a circuit board 4 having a conductive portion 5 and a solder portion 3.
In a flip-chip mounting body in which the conductive portion 5 and the solder portion 3 are electrically connected to face each other, the conductive portion 5 includes the solder portion 5 included in the chip 1. At least a part of the electrode is a protruding electrode that electrically connects the circuit board 4 and the chip 1 to each other.

The flip-chip mounting body according to a second aspect of the present invention is the flip-chip mounting body according to the first aspect of the invention, wherein the protruding electrodes 5a and 5c have at least one convex portion 51 at the tip.
It is characterized by comprising.

The flip chip mounting body according to a third aspect is the invention according to the first or second aspect,
The protruding electrode 5b is characterized by having at least one conical portion 53 at its tip.

The flip chip mounting body according to a fourth aspect of the present invention is the flip-chip mounting body according to the first or second aspect of the invention.
The protruding electrode 5d is characterized in that it has a caldera-like portion 52 at its tip.

A flip-chip mounting body according to a fifth aspect of the present invention is the flip-chip mounting body according to any one of the first to fourth aspects of the invention, in which the protruding electrodes 5e and 5g are connected to the solder portion 3
It is characterized in that the protruding portion 55 and the base portion 54, which is a supporting portion of the protruding portion 55, are separately formed and then formed so as to be integrated with each other.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the protrusion 55 is a stud bump.

Further, in the flip-chip mounting body according to a seventh aspect, in the invention according to any one of the first to fifth aspects, the protruding electrode 5f is conductive at least at a portion in contact with the solder portion 3. A conductive layer 53 made of a conductive material is provided.

Further, in the flip-chip mounting method according to the seventh aspect, the solder portion 3 provided on the mounting surface of the chip 1 and the conductive portion 5 provided on the surface of the circuit board 4 are opposed to each other at a predetermined position. In a flip-chip mounting method comprising a step of mounting and electrically connecting, the protruding electrodes 5a to 5g are used as the conductive portion 5, and the protruding electrodes 5a to 5g are pressed against the solder portion 3 of the chip 1. And intruding at least a part thereof to press-bond the solder portion 3 and the conductive portion 5 to each other.

Here, the protruding electrode includes any shape having at least a convex portion 51, for example, one having a convex portion 51 at a portion other than the tip portion. included. The solder portion 3 includes a solder bump having an arbitrary shape, a substantially spherical solder ball, and the like.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Since the basic structure of the flip-chip mounting body and the basic method of the flip-chip mounting method are the same as those shown in the related art, the same parts are designated by the same reference numerals and the description of common parts is omitted. To do.

A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic sectional view showing a flip chip mounting body and a flip chip mounting method according to a first embodiment of the present invention.

The flip chip mounting method will be described below. As shown in FIG. 1A and the related art, an electrode pad 2 made of, for example, Al and a solder bump as a solder portion 3 are formed on the chip 1.

Here, the size of the electrode pad 2 is, for example, a size of 50 to 150 μm square and a height of 1 to 3 μm. The size of the solder bump is, for example, 50 to 150 in diameter.
μm, and the height is 50 μm or more.

Here, in the first embodiment, as the conductive portion 5 formed on the circuit board 4, as shown in FIG. 1D, one side surface of the triangular prism is provided on the flat base portion. It has a pentagonal shape with a substantially cross-sectional shape that is a substantially home base shape, and has a convex portion 51 with an acute angle provided at a predetermined length in a certain direction at the tip end on the side connected to the chip 1 side. The protruding electrode 5a is used, and the protruding electrode 5a is formed at a predetermined position on the circuit board 4. The size of the protruding electrode 5a is, for example, 40 to 100 μm in width and 20 μm in height.
As described above, the length may be 40 μm or more and the size that allows the solder to enter the solder portion 3. In addition, the protruding electrode 5a
Is integrally formed of, for example, Cu, and is connected to a circuit (not shown) existing inside the circuit board 4 by, for example, the wiring 8 or the like. Further, the slope extending from the convex portion 51 forms an acute angle and is preferably about 135 degrees or less.

Here, the material forming the protruding electrode 5a is
Although Cu is used, any material having conductivity may be used. In addition, a metal such as Ni, Au, Ag or the like, a conductive paste or the like may be used, or a metal such as Ni, Au, Ag or the like may be conductive. It may be a composite with a conductive paste.

The chip 1 is mounted on the circuit board 4 as follows.
The protrusion electrode 5a is pressed into the solder portion 3 so that a desired amount of the protrusion electrode 5a is penetrated. The subsequent steps are performed in the same manner as the method shown in the conventional technique.

In the flip chip mounting body and the flip chip mounting method, the electrical connection between the chip 1 and the circuit board 4 is provided inside the solder portion 3 by the convex portion 5 of the protruding electrode 5a.
Since it is performed by pressing 1 to make it intrude, there is no need to provide a flux to the solder part 3 or a step of cleaning the flux, so that the gap management between the chip 1 and the circuit board 4 can be facilitated. it can. In addition, since the protruding electrode 5a is inserted into the non-oxidized portion inside the solder portion 3 for pressure bonding, stable electrical connection between the chip 1 and the circuit board 4 can be realized.

The protruding electrode 5a has a convex portion 5 at the tip.
1 is provided, the protrusion electrode 5a
Can be easily penetrated along the slope extending from the convex portion 51. Further, since the protruding electrode 5a has a sloped surface that does not have a concave portion at its tip end and extends from the convex portion 51, and has a structure that does not easily become a resistance when entering the solder portion 3, a force in the shear direction is less likely to occur. In addition, the solder portion 3 is unlikely to come off from the electrode pad 2 provided on the chip 1, and the yield can be improved. Further, a shape such as the protruding electrode 5a having the convex portion 51 at the tip can be easily formed.

Next, embodiments showing different shapes of the conductive portion 5 will be described as second to fourth embodiments of the present invention with reference to FIGS. 2 to 4. Note that the description of the same parts as those of the first embodiment will be omitted by giving the same reference numerals to the same parts.

First, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic sectional view showing a flip chip mounting body according to the second embodiment of the present invention.

In the second embodiment, as the conductive portion 5, as shown in FIG. 2B, a quadrangular pyramidal pyramidal portion including a convex portion 51 at the tip end on a flat plate-shaped base portion. The protruding electrode 5b having a shape in which 53 is arranged is used.

Here, in the conical portion 53 of the protruding electrode 5b,
Although the quadrangular pyramid shape is used, it may have any shape such as a conical shape or a pyramid shape. The size of the bump electrode 5b may be, for example, 40 to 100 μm square, 20 μm or more in height, and the size that allows it to enter the solder part 3. The bump electrode 5b is made of, for example, Cu and is integrally formed. Further, it is preferable that the inclined surface of the conical portion 53 forms an acute angle and that the cross section including the diagonal hypotenuse is approximately 150 degrees or less.

In the flip chip mounting body and the flip chip mounting method, by using the protruding electrode 5b having the weight-shaped portion 53 at the tip, the protruding electrode 5b is lowered in the non-oxidized portion inside the solder portion 3. It can be easily inserted by pressure and connected by crimping. Chip 1 and circuit board 4
A stable electrical connection with can be realized.

The protruding electrode 5b has a cone-shaped portion 5 at the tip.
3 is provided, the protruding electrode 5b
Can easily enter along the inclined surface of the weight portion 53. Further, since the protruding electrode 5b does not have a concave portion at the tip and has an inclined surface of the weight portion 53, and has a structure that does not easily become a resistance when entering the solder portion 3, a force in the shearing direction is hard to be generated. In addition, the solder portion 3 is unlikely to come off from the electrode pad 2 provided on the chip 1, and the yield can be improved. Further, a shape such as the protruding electrode 5b having the conical portion 53 at the tip can be easily formed.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing a flip-chip mount body according to the third embodiment of the present invention.

In the third embodiment, as the conductive portion 5, as shown in FIG. 3B, a shape in which four convex portions 51 are provided on a flat base portion, for example, a cross-sectional shape. The protruding electrode 5c has a comb-like shape and is provided with an acute-angled convex portion 51 at the tip for a predetermined length in a certain direction. The protruding electrode 5c is made of, for example, Cu and is integrally formed. The size of the protruding electrode 5c is, for example, 80 to 15 in width.
0 μm, height 18-40 μm, length 100-300
The size may be μm so that the solder part 3 can be penetrated.

In the flip chip mounting body and the flip chip mounting method, the contact area between the protruding electrode 5c and the solder portion 3 can be increased by using the protruding electrode 5c having the plurality of convex portions 51. Therefore, stable electrical connection between the chip 1 and the circuit board 4 can be realized.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic sectional view showing a flip chip mounting body according to the fourth embodiment of the present invention.

In the fourth embodiment, as the conductive portion 5, as shown in FIG. 4, a part of the weight portion 53 of the protruding electrode 5b in the second embodiment is cut substantially parallel to the surface of the circuit board 4. A protruding electrode 5d having a shape in which a caldera-shaped portion 52 is provided in the substantially central portion of the cut portion is used. The upper end of the caldera-shaped portion 52 has a convex portion 5 that forms a square ring shape.
Contains 1.

The caldera-like portion 52 may have a width of, for example, 30 to 100 μm and a depth of 50 μm or less, and may be smaller than the solder portion 3. The size of the protruding electrode 5d is, for example, 40 to 200 μm in width and 40 μm in length.
As described above, the height may be 18 μm or more and the size that allows the solder to enter the solder portion 3. The protruding electrode 5d
Is made of, for example, Cu and is integrally formed.

In the flip chip mounting body and the flip chip mounting method, the contact area between the protruding electrode 5d and the solder portion 3 can be increased by using the protruding electrode 5d provided with the caldera-like portion 52. A stable electrical connection between the chip 1 and the circuit board 4 can be realized.

In the first to fourth embodiments, the conductive portion 5 may be made of a single material, or a plurality of materials may be laminated, for example.

Next, an embodiment showing another shape of the conductive portion 5 will be shown in FIG. 5 as a fifth embodiment to a seventh embodiment of the present invention.
It will be described with reference to FIG. Note that the description of the same parts as those of the first embodiment will be omitted by giving the same reference numerals to the same parts.

First, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic sectional view showing a flip-chip mount body according to the fifth embodiment of the present invention.

In the fifth embodiment, as the conductive portion 5, as shown in FIG. 5B, the base portion 54 is a flat plate-shaped electrode pad made of, for example, Cu, Ni, Au, or the like, which has micro holes (not shown). ) Is provided, and the protruding electrode 5e in which a needle-shaped conductor made of, for example, a Cu wire, a Ni wire, an Au wire or the like is fitted into the minute hole as the protruding portion 55 is used. It should be noted that the tip portion of the protruding portion 55 constitutes the convex portion 51.

Here, the base portion 54 has a size larger than that of the solder portion 3, and may have a size that does not affect the surrounding wiring (not shown). The protruding portion 55 has, for example, 15 to 15 parts protruding upward from the surface of the base part 54.
The height is 50 μm, which is smaller than the height of the solder part 3. Further, the diameter of the protruding portion 55 may be 100 μm or less, for example, and may be smaller than the diameter of the solder portion.

Further, the diameter of the minute hole provided in the base portion 54 is
It may be larger than the diameter of the protruding portion 55 and may have any depth as long as it does not affect a circuit (not shown) existing inside the circuit board 4. Further, the protruding portion 55 to be inserted into the minute hole may be fixed with a conductive resin or the like.

In the flip-chip mounting body and the flip-chip mounting method, since a flat plate-shaped electrode pad is formed as the base portion 54, a needle-shaped conductor is provided as the protruding portion 55 to form the protruding electrode 5e. It is possible to form the protruding electrode 5e having the protruding portion 55 on various circuit boards 4 having the flat plate-shaped electrode pads.

Further, since the protruding electrode 5e is provided with the protruding portion 55 at the tip portion thereof, the protruding electrode 5e with respect to the solder portion 3 is formed.
The e can easily enter along the inclined surface of the protrusion 55. In addition, the protruding electrode 5e does not have a concave portion at the tip and has an inclined surface of the protruding portion 55,
Since the structure is less likely to become a resistance when entering the solder part 3, a force in the shearing direction is unlikely to be generated, so that the solder part 3 is less likely to come off from the electrode pad 2 provided on the chip 1, and the yield is also improved. Can be achieved. Further, the shape like the protruding portion 55 can be easily formed.

Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view showing a flip-chip mount body according to the sixth embodiment of the present invention. In the sixth embodiment, first, a desired convex portion on the surface of the circuit board 4,
For example, a pentagonal portion having a substantially home-shaped cross section, such as the bump electrode 5a in the first embodiment, is formed by using, for example, a thermosetting resin paste, and heat treatment is applied to cure the pentagonal portion. In addition, the convex portions formed on the surface of the circuit board 4 may be collectively formed at the time of molding the circuit board, such as a circuit board manufactured by using the MID technique.

Next, the surface of the pentagonal portion is covered with a conductive layer 56 of, for example, Cu to form a protruding electrode 5f which is the conductive portion 5 as shown in FIG. 6B. Here, Cu conductive layer 5
The thickness of 6 is, for example, 5 to 40 μm. In addition to Cu, Ni, Au, or the like may be used to form the conductive layer 56. When Ni is used as the conductive layer 56, the thickness is, for example, 3 μm or more, and when Au is used, for example, 0.02 μm or more. Is.

In the flip chip mounting body and the flip chip mounting method, the conductive layer 5 is formed on at least the surface.
By forming the protruding electrode 5f by covering it with 6, it is not necessary to form the inside of the protruding electrode 5f which is the conductive portion 5 with a conductive material, so that the protruding electrode 5f with reduced material cost can be provided.

Finally, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 7 is a schematic sectional view showing a flip chip mounting body according to the seventh embodiment of the present invention.

In the seventh embodiment, as the conductive portion 5, as shown in FIG. 7B, the protrusion portion 55 is formed on the electrode pad made of, for example, Cu having a flat plate shape as the base portion 54.
For example, a stud bump made of Au is provided and the protruding electrode 5g is used. Here, the tip portion of the protruding portion 55 constitutes the convex portion 51.

The size of the stud bump is, for example, 50 μm or more in diameter and less than or equal to the height of the solder portion 3, but the height may be appropriately adjusted by leveling or the like.

In the flip-chip mounting body and the flip-chip mounting method, since the plate-shaped electrode pad is formed as the base portion 54 and the stud bump is provided as the protruding portion 55 to form the protruding electrode 5g, the normal plate-shaped electrode is formed. The protruding electrodes 5g can be formed on various circuit boards 4 provided with the electrode pads.

Further, since the protruding electrode 5g is provided with a stud bump as the protruding portion 55 at the tip portion, the protruding electrode 5g can easily enter the solder portion 3. Further, since the protruding electrode 5g does not have a concave portion at its tip and has a structure that does not easily become a resistance when entering the solder part 3, a force in the shearing direction is hard to be generated, and therefore the electrode pad 2 provided on the chip 1 It is less likely that the solder portion 3 will come off, and the yield can be improved.

Here, in the first to seventh embodiments, the chip 1 is mounted on the circuit board 4 by the solder portion 3
The protrusion electrodes 5a to 5g are pressed into the inside to inject a desired amount. For example, about 1/5 or more of the entire height of the protrusion electrodes 5a to 5g from the tip of the protrusion electrodes 5a to 5g, preferably about 1 Perform by injecting / 3 or more.

[0056]

As described above, in the flip chip mounting body according to the first aspect, at least a part of the bump electrode provided on the circuit board side enters the inside of the solder portion provided on the chip side, and A flip chip mounting body that facilitates gap management between the chip and the circuit board and realizes stable electrical connection between the chip and the circuit board because the chip and the circuit board are electrically connected. Could be provided.

Further, in the flip-chip mounting body according to the second aspect, in the invention according to the first aspect, by using the protruding electrode having at least the convex portion at the tip,
The bump electrode can easily be inserted into the non-oxidized portion inside the solder portion with a low load to perform crimp connection, and stable electrical connection between the chip and the circuit board can be realized. .

Further, in the flip-chip mounting body according to claim 3, in the invention according to claim 1 or 2, the solder portion is provided by using the protruding electrode having the weight-shaped portion at the tip. The protruding electrodes can easily be inserted into the non-oxidized portion of the inside with a low load to be pressure-bonded, and a stable electrical connection between the chip and the circuit board can be realized.

Further, in the flip-chip mounting body according to the fourth aspect, in the invention according to the first aspect or the second aspect, by using the protruding electrode having the caldera-like portion, Since the contact area with the solder portion can be increased, there is an effect that stable electrical connection between the chip and the circuit board can be realized.

Further, in the flip chip mounting body according to claim 5, in the invention according to any one of claims 1 to 4, after the base portion of the conductor is formed, the base portion is formed. Since the protruding portion of the conductor is provided as the support to form the protruding electrode, the protruding electrode can be easily formed only by providing the protruding portion on various circuit boards having the usual electrode pads as the base portion. The effect that it can be formed in.

Further, in the flip-chip mounting body according to the sixth aspect, in the invention according to the fifth aspect, the protrusion electrode can be easily formed by using the stud bump for the protrusion portion. Has the effect.

Further, in the flip-chip mounting body according to claim 7, in the invention according to any one of claims 1 to 5, at least the surface is covered with a conductive layer to form a protruding electrode. Then, since it is not necessary to form the inside of the protruding electrode with a conductive material, it is possible to provide the protruding electrode with reduced material cost.

Further, in the flip-chip mounting method according to the eighth aspect, the protruding electrode is used as the conductive portion provided on the circuit board side, and the protruding electrode is pressed against the solder portion of the chip so that at least a part of the protruding electrode is pressed. Since the solder part and the conductive part are pressure-bonded by being intruded, there is no need to provide a flux to the solder part or a flux cleaning process, so that the gap between the chip and the circuit board can be easily managed. In addition, it is possible to provide a flip chip mounting method that realizes stable electrical connection between the chip and the circuit board.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a flip-chip mounting body and a flip-chip mounting method according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a flip chip mounting body according to a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing a flip chip mounting body according to a third embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing a flip-chip mount body according to a fourth embodiment of the present invention.

FIG. 5 is a schematic sectional view showing a flip chip mounting body according to a fifth embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing a flip chip mounting body according to a sixth embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view showing a flip chip mounting body according to a seventh embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view showing a flip-chip mounting body and a flip-chip mounting method according to a conventional example.

[Explanation of symbols]

1 chip 2 electrode pad 3 Solder part 4 circuit board 5 Conductive part 5a to 5f protruding electrode 6 Sealing resin 7 Flux 8 wiring 51 convex part 52 Caldera-shaped part 53 Conical part 54 Base 55 Projection 56 Conductive layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinobu Kida             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F-term (reference) 5E319 AA03 AB05 AC01 AC16 AC17                       CC12 CC33 CD04 GG03 GG09                       GG15                 5E336 AA04 AA16 BC28 BC37 CC32                       CC44 CC55 DD37 DD39 EE01                       EE05 GG05 GG16                 5F044 KK17 KK18 KK19 LL01 LL04                       QQ03

Claims (8)

[Claims] 1. A flip-chip mounting body comprising a circuit board having a conductive portion and a chip having a solder portion, wherein the conductive portion and the solder portion are electrically connected to face each other. The portion is a flip-chip mounting body that is a protruding electrode that at least partially penetrates into the solder portion of the chip and electrically connects the circuit board and the chip. 2. The flip chip mounting body according to claim 1, wherein the protruding electrode has at least one convex portion at a tip portion thereof. 3. The flip chip mounting body according to claim 1, wherein the protruding electrode has at least one conical portion at a tip portion thereof. 4. The flip chip mounting body according to claim 1, wherein the protruding electrode has a caldera-like portion at a tip portion thereof. 5. The projecting electrode is formed so that a projecting portion that has penetrated into the solder portion and a base portion that is a supporting portion of the projecting portion are separately formed, and then the both are integrated.
The flip chip mounting body according to claim 4. 6. The flip chip mounting body according to claim 5, wherein the protruding portion is a stud bump. 7. The flip chip mounting body according to claim 1, wherein the protruding electrode is provided with a conductive layer made of a conductive material at least in a portion in contact with the solder portion. 8. A flip chip mounting comprising a step of mounting a solder portion provided on a mounting surface of a chip and a conductive portion provided on a surface of a circuit board so as to face each other and electrically connecting them at a predetermined position. In the method, a flip electrode including a step of using a protruding electrode as the conductive portion and pressing the protruding electrode against a solder portion of the chip to intrude at least a part of the solder portion to press-bond the solder portion and the conductive portion. Chip mounting method.