JP2000306428A - Anisotropic conductive adhesive and conductive connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent conductive connection defects from occurring if the distance between connection terminals is increased to some extent by a temperature change, etc., in a use environment. SOLUTION: Conductive particles 17 in an anisotropic conductive adhesive 15 are each made up by forming an insulation film 17b made of silicon oxide, glass, resin, etc., on a surface of a core 17a or a relatively hard metal particle such as nickel particle with corners or projections, and forming a conductive film 17c of metal plating such as nickel plating on a surface of the insulation film 17b. If the distance between connection terminals 12, 14 facing each other is increased to some extent, the conductive films 17c stuck on and biting into the connection terminals 12, 14 can prevent conducting connection defects from occurring by being appropriately peeled off from the insulation films 17b or being appropriately peeled, together with the insulation films 17b, off from the cores 17a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an anisotropic conductive adhesive and a conductive connection structure.

[0002]

2. Description of the Related Art In a liquid crystal display device, for example, a semiconductor chip composed of an LSI or the like for driving a liquid crystal display panel is mounted on one glass substrate constituting the liquid crystal display panel via an anisotropic conductive adhesive. is there.

FIG. 2A is a partial cross-sectional view of an example of such a conventional liquid crystal display device. A connection terminal 2 made of an aluminum-based metal such as aluminum or an aluminum alloy is provided at a predetermined position on the upper surface of one glass substrate 1 constituting the liquid crystal display panel. A connection terminal 4 made of a gold bump is provided at a predetermined position on a lower surface of a semiconductor chip 3 made of an LSI or the like for driving a liquid crystal display panel. The anisotropic conductive adhesive 5 is formed by dispersing conductive particles 7 in an insulating adhesive 6 made of a thermosetting resin or the like. In this case, as the conductive particles 7, FIG.
As shown in (B), a core 7a made of relatively hard metal particles such as nickel having corners or projections and a coating film 7b made of a relatively soft metal such as solder formed on the surface is used. (See Japanese Patent Application Laid-Open No. 5-12916).

When an anisotropic conductive adhesive 5 is interposed between the connection portion including the connection terminal 2 of the glass substrate 1 and the connection portion including the connection terminal 4 of the semiconductor chip 3 and is thermally compressed, a difference occurs. A part of the conductive particles 7 of the isotropic conductive adhesive 5 comes into contact with the connection terminals 2 and 4 facing each other, whereby the connection terminals 2 and 4 facing each other are conductively connected. When the insulating adhesive 6 of the anisotropic conductive adhesive 5 is cured, the connection portion including the connection terminal 2 of the glass substrate 1 and the connection portion including the connection terminal 4 of the semiconductor chip 3 are bonded. Thus, the semiconductor chip 3 is mounted on the upper surface of the glass substrate 1 via the anisotropic conductive adhesive 5.

Since the core 7a of the conductive particles 7 is made of relatively hard metal particles such as nickel having corners or protrusions, the surface of the connection terminal 2 made of aluminum-based metal on the glass substrate 1 is naturally oxidized. Even if a film (not shown) is formed, the corners or projections of the core 7a exposed from the coating film 7b deformed by the thermocompression bonding penetrate the natural oxide film and bite into the surface of the connection terminal 2, whereby
Conductive connection between the connection terminals 2 and 4 facing each other is ensured.

[0006]

However, in such a conventional conductive connection structure, as the conductive particles 7, solder or the like is formed on the surface of a core 7a made of relatively hard metal particles such as nickel having corners or projections. Since a coating film 7b made of relatively soft metal is used,
The coating film 7b deformed by the thermocompression bonding maintains its deformed state even after the thermocompression bonding. For this reason, when the interval between the connection terminals 2 and 4 facing each other becomes large to some extent due to a temperature change of the use environment or the like, the conductive particles 7 are separated from at least one of the connection terminals 2 and 4. State, resulting in a problem that conductive connection failure occurs. SUMMARY OF THE INVENTION It is an object of the present invention to prevent a conductive connection failure from occurring even when the interval between connection terminals facing each other is increased to some extent.

[0007]

According to the first aspect of the present invention,
In an anisotropic conductive adhesive obtained by dispersing conductive particles in an insulating adhesive, the conductive particles, an insulating film is formed on the surface of a core made of metal particles having corners or protrusions,
It is constituted by a conductive film formed on the surface of the insulating film. According to a third aspect of the present invention, a conductive particle is dispersed in an insulating adhesive between a connection portion including a connection terminal of one electronic component and a connection portion including a connection terminal of another electronic component. In a conductive connection structure in which an isotropic conductive adhesive is interposed and the connection terminal of the one electronic component and the connection terminal of the other electronic component are conductively connected via the conductive particles, An insulating film is formed on a surface of a core made of metal particles having corners or projections, and a conductive film is formed on the surface of the insulating film. According to the present invention, the conductive particles are formed by forming an insulating film on the surface of a core made of metal particles having corners or protrusions, and forming a conductive film on the surface of the insulating film. When the conductive film in the portion corresponding to the corner or the protrusion of the core bites into the surface of the connection terminal, the conductive connection between the connection terminals facing each other is secured. When the distance between the connection terminals facing each other becomes large to some extent, the conductive film that bites into and adheres to the surfaces of the connection terminals is appropriately peeled off from the insulating film or from the core together with the insulating film. Accordingly, it is possible to prevent a conductive connection failure from occurring.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a sectional view showing a state in which a connection terminal of a glass substrate and a connection terminal of a semiconductor chip are conductively connected using an anisotropic conductive adhesive according to an embodiment of the present invention. FIG. 1B is an enlarged cross-sectional view of a part of FIG. A connection terminal 12 made of an aluminum-based metal such as aluminum or an aluminum alloy is provided at a predetermined location on the upper surface of the glass substrate 11. At predetermined positions on the lower surface of the semiconductor chip 13, connection terminals 14 made of gold bumps are provided.

The anisotropic conductive adhesive 15 is formed by dispersing conductive particles 17 in an insulating adhesive 16 made of a thermosetting resin or the like. In this case, the conductive particles 17
An insulating film 17 made of silicon oxide, glass, resin, or the like is formed on the surface of a core 17a made of metal particles having corners or projections.
b, and a conductive film 17c made of metal plating is formed on the surface of the insulating film 17b. The material of the core 17a is a metal (including an alloy) that is harder than the connection terminals 12 and 14, specifically, nickel, chromium, iron, stainless steel, copper, or the like, and preferably has a surface projection property. Nickel. The material of the conductive film 17c is a metal (including an alloy) having a hardness substantially equal to or higher than that of the connection terminals 12 and 14, specifically, an aluminum-based metal, gold, silver, nickel, chromium, copper, or the like. , Preferably nickel, which is the same as the material of the core 17a. Core 17a
Has an average diameter of about 3 to 5 μm, the thickness of the insulating film 17b is about several thousand Å, and the thickness of the conductive film 17c is about several thousand Å.

Then, an anisotropic conductive adhesive 15 is interposed between the connection portion including the connection terminal 12 of the glass substrate 11 and the connection portion including the connection terminal 1 of the semiconductor chip 13, and is thermocompression-bonded. , Conductive particles 17 of anisotropic conductive adhesive 15
Are in contact with the connection terminals 12 and 14 facing each other,
Thus, the connection terminals 12 and 14 facing each other are conductively connected. The insulating adhesive 1 of the anisotropic conductive adhesive 15
6 is cured, the connection terminals 1 of the glass substrate 11 are hardened.
2 and the connection portion including the connection terminal 14 of the semiconductor chip 13 are bonded. Thus, the glass substrate 1
A semiconductor chip 13 is mounted on an upper surface of the semiconductor chip 1 via an anisotropic conductive adhesive 15.

The core 17a of the conductive particles 17 is made of metal particles which are harder than the connection terminals 12 and 14 and have corners or projections.
Since a metal plating film substantially the same as or harder than the metal plating films 2 and 14 is used, even if a natural oxide film 12a is formed on the surface of the connection terminal 12 made of an aluminum-based metal on the glass substrate 11, the corner of the core 17a is formed. Alternatively, the conductive film 17c in a portion corresponding to the protrusion penetrates the natural oxide film 12a and cuts into the surface of the connection terminal 12, and the core 17a
The conductive film 17c at a portion corresponding to the corner or protrusion of the semiconductor chip 13 cuts into the surface of the connection terminal 14 formed of the gold bump of the semiconductor chip 13, thereby forming the connection terminal 12, 1
A conductive connection between the four is ensured. Although not illustrated, when the distance between the connection terminals 12 and 14 facing each other is increased to some extent due to a temperature change of the use environment or the like,
At least one side of the conductive film 17c biting and adhering to the surfaces of the connection terminals 12 and 14 is an insulating film 17b.
From the core 17 together with the insulating film 17b.
a can be appropriately peeled off, thereby preventing a conductive connection failure from occurring, and thereby improving the reliability of the conductive connection.

In the above embodiment, the glass substrate 11
Terminal 12 made of aluminum-based metal formed on
A case has been described in which conductive connection is made between the semiconductor device and the connection terminal 14 formed of a gold bump formed on a semiconductor chip. However, the present invention is not limited to this. For example, a connection terminal made of an aluminum-based metal or ITO formed on a glass substrate and a connection terminal made of copper or the like formed on a flexible wiring substrate may be conductively connected. In addition, a connection terminal made of copper or the like formed on a flexible wiring board and CS
A connection terminal formed of a columnar electrode made of gold or the like formed on a semiconductor device and called a P (chip size package) or the like may be conductively connected.

[0013]

As described above, according to the present invention, the conductive film is formed on the surface of the core made of metal particles having corners or projections, and the conductive film is formed on the surface of the insulating film. Because it is composed by what is formed,
When the distance between the connection terminals facing each other becomes large to some extent, the conductive film that bites into and adheres to the surface of the connection terminal is appropriately peeled off from the insulating film or from the core together with the insulating film. The connection failure can be prevented from occurring, and the reliability of the conductive connection can be improved.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a state in which a connection terminal of a glass substrate and a connection terminal of a semiconductor chip are conductively connected using an anisotropic conductive adhesive according to one embodiment of the present invention;
Is an enlarged sectional view of a part thereof.

FIG. 2A is a cross-sectional view showing a state in which a connection terminal of a glass substrate and a connection terminal of a semiconductor chip are conductively connected using a conventional anisotropic conductive adhesive, and FIG. FIG. 3 is an enlarged cross-sectional view of the conductive particles of the agent.

[Explanation of symbols]

 Reference Signs List 11 glass substrate 12 connection terminal 13 semiconductor chip 14 connection terminal 15 anisotropic conductive adhesive 16 insulating adhesive 17 conductive particles 17a core 17b insulating film 17c conductive film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 5/16 H01B 5/16 H01L 21/60 311 H01L 21/60 311S H01R 11/01 H01R 11/01 H

Claims (5)

[Claims] 1. An anisotropic conductive adhesive in which conductive particles are dispersed in an insulating adhesive, wherein the conductive particles form an insulating film on a surface of a core made of metal particles having corners or protrusions. A conductive film formed on the surface of the insulating film. 2. The anisotropic conductive adhesive according to claim 1, wherein the core is made of nickel particles, and the conductive film is made of a nickel plating film. 3. An anisotropic conductive material in which conductive particles are dispersed in an insulating adhesive between a connection portion including a connection terminal of one electronic component and a connection portion including a connection terminal of another electronic component. In a conductive connection structure in which an adhesive is interposed and a connection terminal of the one electronic component and a connection terminal of the other electronic component are conductively connected via the conductive particles, the conductive particles may have corners or protrusions. A conductive connection structure comprising an insulating film formed on a surface of a core made of metal particles having a conductive film formed on the surface of the insulating film. 4. The conductive connection structure according to claim 3, wherein the core is made of nickel particles, and the conductive film is made of a nickel plating film. 5. The conductive connection structure according to claim 4, wherein the connection terminals of the one electronic component are made of an aluminum-based metal, and the connection terminals of the other electronic component are made of gold bumps.