JP3395926B2 - Electrode device - Google Patents

Abstract

PURPOSE: To improve the reliability of the connection between a substrate and a surface mounting type electronic part by electrically connecting the bump of the surface mounting type electronic part to the conducting layer of the uppermost layer, which is exposed through the opening of an organic insulating film. CONSTITUTION: A plurality of conducting layers 24 and 25 are formed within organic insulating films 23 and 27 forming a substrate 20 so that the conducting layers are sequentially aligned at a distance in the direction of the thickness of the organic insulating films 23 and 27. An opening 27A is formed in the insulating film 27 among the organic insulating films 23 and 27 so that a part of the conducting layer 24 is exposed at a part, where the insulating film faces the conducting layer 24 at the uppermost layer. Furthermore, the bump of the surface mounting type electronic part is electrically connected to the conducting layer 24 at the uppermost layer, which is exposed through the opening 27A. Thus, the reliability of the connection between the substrate and the surface mounting type electronic part can be improved.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial applications Conventional technology (Figs. 6 to 9) Problems to be Solved by the Invention (FIGS. 6 to 9) Means for Solving the Problems (FIGS. 1 to 5) Action (Figs. 1-5) Example (FIGS. 1 to 5) The invention's effect

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode device, and is suitable for application to, for example, an electrode of a substrate to which a flip chip is joined by thermocompression bonding.

[0003]

2. Description of the Related Art Conventionally, as one mounting method for mounting a flip chip on a substrate, bumps made of metal are formed on each pad of the flip chip, and these bumps are thermocompression bonded onto corresponding electrodes on a wiring board. There is a method (hereinafter referred to as a thermocompression bonding mounting method) in which the electrical connection is made.

In this case, as a method for forming bumps on each pad of the flip chip, a ball-shaped mass made by melting the tip of a wire made of metal is ultrasonically pressure-bonded and then torn off from the rest of the wire. A method of forming bumps (studded bumps) may be used.

[0005]

Problems to be Solved by the Invention FIGS. 6 and 7
As shown in (A) and (B), in general, the substrate 1 has an organic insulating film layer 3 formed of an organic insulating material such as polyimide on a mother board 2 such as a silicon substrate, and the organic insulating film layer 3 is also formed. After forming the electrodes 4 and other wiring patterns with a conductive material such as copper, a thin organic insulating material (for example, about 1 [μm]) is coated on the upper surface of the organic insulating film layer 3 while avoiding the electrodes 4 and the wiring patterns. (The organic insulating film layer 5 is formed).

In this case, since the organic insulating material has a large elasticity, it is easily bent by pressure, and thus the flip chip is mounted on the conventional substrate 1 having the above-mentioned electrode structure by using the above thermocompression bonding method. If you try to implement it, you will see Fig. 8 (A).
As shown in FIG.
When the flip chip 10 is pressed against the substrate 1 as shown in FIG. 8B after positioning and bonding the substrate 1 so as to contact the corresponding electrode 2 of the substrate 1, the organic insulating film layer below the electrode 4 is formed. 2 is largely bent by the pressure received through the electrode 4, and as a result, the electrode 4 is deformed as shown in FIG.
The electrical conductor forming the rupture may break.

In general, the stud pump is formed by tearing off the tip of the wire ultrasonically pressure-bonded onto the pad of the flip chip 10 as described above. Therefore, when the tip of the wire is torn off, it is formed. , Fig. 9
As shown in (A), a pin-shaped projection 12A may be formed at the tip of the stud bump 12.

In such a case, this stud bump 12
9 is pressed against the corresponding electrode 4 of the substrate 1 as shown in FIG. 9B, the protrusion 12A of the stud bump 12 causes the protrusion of FIG.
As shown in (C), the electrode 4 is fractured, and as a result, the electrode 4 of the substrate 1 and the stud bump 12 of the flip chip 10 are broken.
Contact failure may occur between the and. Therefore, in the conventional substrate 1, when the flip chip 10 is mounted by using the thermocompression bonding method, contact failure is likely to occur between the electrode 4 and the bumps 11 and 12 of the flip chip 10, and the reliability of the connection of the flip chip 10 is improved. There was a low problem.

The present invention has been made in view of the above points, and an object thereof is to propose an electrode device which can improve the reliability of connection between a substrate and a surface-mounted electronic component.

In order to solve such a problem, according to the present invention, a substrate for electrically connecting bumps (11, 12) formed on corresponding pads of a surface mount type electronic component (10) by pressure bonding. In the electrode device for forming the electrode (21) of (20), inside the organic insulating film (23, 27) made of an organic insulating material for forming the substrate (20), in the thickness direction of the organic insulating film (23, 27). A plurality of conductive layers (24, 25) formed so as to be sequentially spaced apart from each other, connection means (26) for electrically connecting the conductive layers (24, 25), and an organic insulating film (23, 27), the portion of the conductive layer (24) facing the uppermost conductive layer (24).
And an opening (27A) formed so that a part of the surface of the organic insulating film (23A) is exposed, and the uppermost conductive layer (24) exposed through the opening (27A) of the organic insulating film (23) has a surface-mounted electronic component ( The bumps (11, 12) of 10) were electrically connected.

Further, in the present invention, the surface mount type electronic component (10) is made of flip chip.

Further, in the present invention, the connecting means (2
6) is a via hole formed inside the organic insulating film (23, 27).

[0013]

[0014]

[0015]

[0016]

In the first aspect of the invention, the organic insulating films (23, 27) made of the organic insulating material forming the substrate (20) are arranged inside the organic insulating film (23, 27) at a distance in the thickness direction of the organic insulating film (23, 27). Thus, the plurality of conductive layers (24, 25) are formed, and the respective conductive layers (24, 25) are electrically connected to each other, and the uppermost conductive layer (2 of the organic insulating films (23, 27) is formed.
4) An opening (27A) is formed in a portion facing the conductive layer (24) so as to expose a part of the conductive layer (24), and conductivity of the uppermost layer exposed through the opening (27A) of the organic insulating film (23). By electrically connecting the bumps (11, 12) of the surface-mounted electronic component (10) to the layer (24), the bumps (11, 1) of the surface-mounted electronic component (10) are connected.
The organic insulating film (2) that constitutes the substrate (20) when thermocompression-bonding 2) to the uppermost conductive layer (24) of the substrate (20).
The uppermost conductive layer (24) by reducing the bending generated in 3)
Of the bump (12) at the same time while preventing the rupture of
Even when the uppermost conductive layer (24) is ruptured by the pin-shaped projections (12A) generated on the lower conductive layer (2A), the lower conductive layer (2
5) by means of the conductive layers (24, 25) of the substrate (20),
It is possible to secure the conductivity between the flip chip (10) and the bumps (11, 12), and thus to realize an electrode device that can improve the reliability of the connection between the substrate and the surface mount electronic component.

[0017]

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

The substrate 20 is shown in FIGS. 1 to 2B, in which the same parts as those in FIGS. 6, 7A and 7B are designated by the same reference numerals.
Shows the electrode 21 of the example formed in FIG. 1, and in addition to the first conductor 24 formed on the organic insulating layer 23 made of an organic insulating material (for example, polyimide), the first conductive material is formed inside the organic insulating layer 23. A second conductor 25 made of a conductive material such as copper is formed so as to face the body 24, and the first and second conductors 24, 25 are conductors formed inside the organic insulating layer 23. It is configured by being electrically and integrally connected by a via hole 26.

In this case, an organic insulating layer 27 made of an organic insulating material is formed on the organic insulating layer 23 while avoiding the tip portion of the first conductor 24. As a result, in this substrate 20, the bumps formed on the flip chip to be mounted are
The first conductor 24 forming the electrode 21 can be electrically connected to the first conductor 24 through the opening 27A of the organic insulating layer 27 formed on the first conductor 24.

Therefore, in this electrode 21, for example, as shown in FIG. 3 (A) in which the same reference numerals are given to the portions corresponding to FIGS. 1-2 (B) and 8 (A)-(C), the flip chip 10 is used. After contacting the bumps 11 with the first conductors 24 of the corresponding electrodes 21 of the substrate 20, the flip chip 10 is pressed against the substrate 20 as shown in FIG. 3B and heated in this state (for example, 150 [°]). 3), the bumps 11 of the flip chip 10 are pressed against the electrodes 21 of the substrate 20 in the thermocompression bonding step of bonding the bumps 11 of the flip chip 10 and the electrodes 21 of the substrate 20 as shown in FIG. 3C. Sometimes (FIG. 3 (A)), the pressure applied to the organic insulating layer 23 below the first conductor 24 via the first conductor 24 (intervened between the first and second conductors 24 and 25). Of the organic insulating layer 23 1) and the bump 11 of the flip chip 10 has the largest portion below the contacting portion) with the second conductor 25 having a low elasticity disposed under the organic insulating layer 23. The organic insulating film layer 23 below the second conductor 25 can be received and dispersed.
The amount of deflection of the Therefore, since the bending of the lower layer portion of the first conductor 24 can be suppressed to a small extent as a whole, the bending of the first conductor 24 itself can be suppressed to a small extent, and thus the bending of the first conductor 24 can be suppressed. It is designed to prevent breakage and connection failure between the bumps 11 of the flip chip 10 and the electrodes 21 of the substrate 20 due to the breakage.

Further, in this electrode 21, FIG. 1 to FIG.
4A to 4C in which parts corresponding to those in FIGS. 9A to 9C are denoted by the same reference numerals, the stud bump 12 of the flip chip 10 having the protrusion 12A is connected to the electrode 21 of the substrate 20. Of the first conductor 24 of FIG.
(A)), after pressing (FIG. 4 (B)), heating (eg,
When the stud bumps 12 are pressure-welded in the step of joining them by about 150 [°] (FIG. 4 (B)),
Even if the first conductor 24 is broken by the protrusion 12A of the stud bump 12, as shown in FIG. 4C, it is electrically connected to the first conductor 24 by the via hole 26. The stud bump 1 on the second conductor 25
Since the second projection 12A pierces, the conductivity between the stud bump 12 and the electrode 21 of the substrate 20 can be secured, and thus the stud bump 12 of the flip chip 10 and the electrode 21 of the substrate 20 due to the destruction of the first conductor 24. It is designed to prevent poor connection with the.

In the case of the embodiment, the radius of the disk-shaped tip portion 24A (FIGS. 1 and 2B) of the first conductor 24 is 120.
The radius of the second conductor 25 is selected to be about 140 [μm].

Here, in practice, the substrate 20 having the electrode 21 having such a structure can be formed by the steps shown in FIGS. That is, first, an organic insulating material such as polyamide is applied to the silicon substrate 2 by spin coating or the like to form a final organic insulating layer 23 (see FIGS.
The first organic insulating film layer 40 is formed by applying a thinner layer than the thickness of (B)) (FIG. 5A).

Subsequently, a conductive layer 41 made of a conductive material such as a metal is formed on the first organic insulating film layer 40 by a method such as sputtering (FIG. 5B), and then the conductive layer 4 is formed.
1 is coated with a photoresist to form a resist layer 42, and the resist layer 42 is exposed to a predetermined pattern using a glass mask 43 or the like (see FIG.
(C)), by developing, the resist layer 42 is shaped into a pattern similar to a desired circuit pattern (FIG. 5D).

Then, the conductive layer 41 exposed through the resist layer 42 is wet or dry-etched to shape the conductive layer 41 itself into a circuit pattern similar to that of the resist layer 42 (that is, a desired circuit pattern) (FIG. 5).
(E)), the conductive layer 41 that will later form a circuit pattern and the first organic insulating film layer 40 exposed from the conductive layer 41.
A second organic insulating film layer 44 is formed on top.

Thereafter, the same steps as in FIGS. 5A to 5F are repeated, and at this time, a second layer is formed on the lower layer portion of the conductive layer 45 (FIG. 5G) corresponding to the first conductor 24. Conductor 2
A conductive layer 41 portion corresponding to 5 is formed. Thereby, the multilayer wiring board 46 having the electrodes 21 having the structure shown in FIGS. 1 to 2B can be formed.

The first conductor 24 and the second conductor 25
The via hole 26 for electrically connecting to and can be formed by exposing using a photosensitive polyimide, or by applying a resist to the polyimide and aging. In the above-described structure, the electrode 21 includes the first and second conductors 24 and 25 laminated in parallel and at a distance from each other on and inside the organic insulating film layer 23 forming the substrate 20. It is formed by electrically connecting the second conductors 24 and 25 with via holes 26.

Therefore, as described above, the flip chip 10
When the bumps 11 and 12 are thermocompression bonded, the organic insulating film layer 2
3 can be prevented from being bent due to the pressure received via the first conductor 24 to prevent the first conductor 24 from rupturing, and at this time, the bump 12 has the protrusion 12A. Even when the first conductor 24 is broken, the second conductor 25 can ensure the conductivity between the electrode 21 of the substrate 20 and the bump of the flip chip 10.
Thus, it is possible to effectively reduce the incidence of contact failure between the electrode 21 of the substrate 20 and the bumps 11 and 12 of the flip chip 10.

According to the above structure, the first and second conductors 24, 2 are provided inside the organic insulating film layer 23 forming the substrate 20.
5 is laminated in parallel and at a distance, and the electrodes 21 of the substrate 20 are formed by electrically connecting the first and second conductors 24 and 25 with the via holes 26. Bump 1 of 10
The first conductor 2 is formed by reducing the bending that occurs in the organic insulating film layer 23 forming the substrate 20 when thermocompressing the first and the second conductors 12.
4 can be prevented, and at the same time, even if the first conductor 24 is torn by the pin-shaped projection 12A formed on the bump 12, the second conductor 25 causes the electrode 21 of the substrate 20 and Bump 11 of flip chip 10,
It is possible to ensure conductivity between the two, and thus the substrate 20
Electrode 21 and bumps 11 and 12 of flip chip 10
It is possible to realize an electrode that can effectively reduce the occurrence rate of contact failure between the electrodes.

In the above embodiments, the case where the organic insulating film layer 23 is made of polyimide has been described, but the present invention is not limited to this, and other organic insulating materials such as benzocyclobutene are used. Alternatively, the organic insulating film layer 23 may be formed.

In the above-described embodiment, the electrode 21 according to the embodiment is formed by stacking the first and second conductors 24 and 25 inside the organic insulating film layer 23 in parallel and at a distance. However, the present invention is not limited to this, and a plurality of conductors are arranged inside the organic insulating film layer 23 in parallel with each other with a distance therebetween, and these conductors are formed using the via holes 26 and the like. The electrodes may be formed so as to be electrically connected. Even in this case, the same effect as that of the embodiment can be obtained.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the electrode 21 of the substrate 20 for thermocompression bonding the stud bumps 11 and 12 of the flip chip 10 has been described, but the present invention is not limited to this. Besides, it is suitable to be applied to the electrodes 21 of various substrates 20.

Further, in the above embodiment, the case where the first and second conductors 24 and 25 are electrically connected by the single via hole 26 has been described, but the present invention is not limited to this. Instead, a plurality of via holes 26 may be used for electrical connection.

Further, in the above-mentioned embodiment, the case where the electrode 21 according to the embodiment is formed by the steps shown in FIGS. 5A and 5G has been described, but the present invention is not limited to this. As the method of forming the electrode 21, various other forming methods can be applied.

Further, in the above-described embodiment, the radius of the tip portion 24A of the first conductor 24 is selected to be about 120 [μm] and the radius of the second conductor 25 is selected to be about 140 [μm]. However, the present invention is not limited to this, and various other sizes and shapes may be applied as the sizes and shapes of the first and second conductors 24 and 25. it can.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the electrode 21 of the substrate 20 for joining the bumps 11 and 12 of the flip chip 10 has been described, but the present invention is not limited to this. Other TAB (Tape Auto
It can also be applied to electrodes for bonding bumps such as mated bonding), and further to electrodes to which signal lines are bonded by COB (chip on board) or wire bonding method.

[0038]

As described above, according to the present invention, a plurality of conductive layers are arranged inside an organic insulating film made of an organic insulating material forming a substrate so as to be sequentially arranged in the thickness direction of the organic insulating film. The organic insulating film is formed and electrically connected to each other, and an opening formed so that a part of the conductive layer is exposed is provided in a portion of the organic insulating film facing the uppermost conductive layer. By electrically connecting the bumps of the surface-mounted electronic component to the uppermost conductive layer exposed through the opening of the film, the bumps of the surface-mounted electronic component are heated to the uppermost conductive layer of the substrate. At the time of crimping, it is possible to reduce the bending that occurs in the organic insulating film that constitutes the substrate and prevent the uppermost conductive layer from rupturing. If the lower layer is broken, A conductive layer by connexion substrate layer, it is possible to secure the conductivity between the bumps of the flip chip, thus can realize an electrode system capable of improving the reliability of the connection between the substrate and the surface mount electronic device.

[0039]

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a substrate electrode according to an embodiment.

2A and 2B are a top view and a side view showing a configuration of a substrate electrode according to an example.

FIG. 3 is a cross-sectional view for explaining an electrode of an embodiment when thermocompression bonding a bump of a bare chip.

FIG. 4 is a cross-sectional view for explaining the destruction of the electrode of the example by the bump having the pin-shaped protrusion.

FIG. 5 is a cross-sectional view for explaining a method for forming a substrate having electrodes according to an example.

FIG. 6 is a perspective view showing a configuration of a conventional substrate electrode.

7A and 7B are a top view and a side view showing a configuration of a conventional substrate electrode.

FIG. 8 is a cross-sectional view for explaining a conventional electrode during thermocompression bonding of a bump of a bare chip.

FIG. 9 is a cross-sectional view for explaining the destruction of a conventional electrode by a bump having a pin-shaped protrusion.

[Explanation of symbols]

20 ... Substrate, 21 ... Electrode, 23, 27, 40, 44
...... Organic insulating film layer, 24, 25 …… conductor, 26 …… via hole, 27A …… opening.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-63-100740 (JP, A) JP-A-3-246047 (JP, A) JP-A-4-82241 (JP, A) JP-A-5- 144872 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/60

Claims (3)

(57) [Claims] 1. An electrode device for forming an electrode of a substrate for electrically connecting a bump formed on a corresponding pad of a surface mount electronic component by pressure bonding, the organic insulating material forming the substrate. A plurality of conductive layers formed inside the organic insulating film, which are sequentially arranged in the thickness direction of the organic insulating film so as to be spaced apart from each other, and connecting means for electrically connecting the conductive layers, respectively. Of the insulating film, an opening formed so that a part of the conductive layer is exposed at a portion facing the conductive layer of the uppermost layer, of the uppermost layer exposed through the opening of the organic insulating film. An electrode device, wherein the bump of the surface-mounted electronic component is electrically connected to a conductive layer. 2. The electrode device according to claim 1, wherein the surface mount type electronic component is a flip chip. Wherein said connecting means according to claim 1, characterized in that in via holes formed inside the organic insulating film
The electrode device according to.