JPH06222373A - Circuit connection method - Google Patents

Abstract

(57) [Abstract] [Purpose] Regarding the circuit connection method, to ensure the insulation resistance between adjacent connections for narrow-pitch connections, and to improve the efficiency of connection work. [Structure] An insulating layer (anodized layer 3) is laminated on the surface of the extraction electrode 2 on the circuit board, and the insulating layer is broken by the conductive particles 4 in the anisotropic conductive adhesive 5 to realize the connection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit connecting method.

[0002]

2. Description of the Related Art In the recent development of parts and devices, how to realize high-density circuit connection has become an issue.

Particularly in devices such as liquid crystal panels, realization of a large number of points and high-density connection is an important point in manufacturing. Therefore, in the present specification, the following description of conventional examples and examples will be made by taking a liquid crystal panel as an example.

A conventional method of connecting circuits of a liquid crystal panel will be described below with reference to the drawings.

FIG. 5 is a perspective view showing a conventional liquid crystal panel. A resin film 6 having a drive IC 9 for driving liquid crystal is mounted on a glass substrate 7. Although not shown, an external substrate is provided outside the resin film 6, and electric signals and power are supplied to the resin film 6 from the external substrate. Such a mounting form is referred to as TAB (Tape Auto).
It is called a "matted bonding" method and is the mainstream of the liquid crystal panel manufacturing method (eg, Atsumi et al., "TAB mounting technology for liquid crystal modules", Electronic Technology, Vol.
issue).

FIG. 6 is a cross-sectional view showing a conventional method for connecting circuits in a liquid crystal panel. A lead 1 formed of a copper foil or the like on a resin film 6 of polyimide or the like is connected to a lead electrode 2 on the liquid crystal panel. The conductive particles 4 dispersed in the adhesive 5 come into contact with the leads 1 and the extraction electrodes 2 to realize electrical connection. Lead 1 to reduce contact resistance
The electrode 2 is plated with Au, Sn, etc.
In many cases, a material such as ITO that has a stable surface and is hard to form an oxide film is used. In a normal operation, a film-shaped or paste-shaped adhesive 5 mixed with conductive particles 4 is attached to or applied on a portion of the glass substrate 7 where the extraction electrode 2 is arranged, and then formed on the resin film 6. The lead 1 is accurately aligned with the extraction electrode 2 on the glass substrate 7, and thermocompression bonded from above.

In addition, a TFT (Thin Film Tr)
In a liquid crystal panel using an anistor), the surface of the glass substrate 7 is often protected by a nitride film or the like,
In that case, as shown in FIG. 7, the extraction electrode 2 of the protective film 8 is formed.
An opening is provided on the top and is connected. In this conventional example, the opposing supports are the resin film 6 and the glass substrate 7, the connecting circuit is the lead 1 and the lead electrode 2, and the electrical connecting member is the adhesive 5 in which the conductive particles 4 are dispersed.

[0008]

However, in such a construction method, as shown in the drawing, the conductive particles 4 are also present between the adjacent extraction electrodes 2 or the leads 1 and the insulation resistance between the adjacent electrodes is deteriorated. Cause This problem becomes more serious as the liquid crystal panel becomes finer and the connection pitch becomes finer. Although the size of the conductive particles 4 is reduced to reduce the connection pitch, it becomes difficult to uniformly disperse the conductive particles 4 in the adhesive 5 as the particle diameter decreases. A phenomenon occurs in which the individual conductive particles 4 aggregate. Therefore, the adjacent extraction electrode 2 or lead 1
Particles agglomerated during this deteriorate the insulation resistance.

Thus, ensuring insulation between adjacent connecting circuits has been a major problem in the circuit connecting method.

The present invention solves such problems and provides a stable circuit connecting method even in a narrow pitch connection.

[0011]

In order to achieve the above-mentioned object, the circuit connecting method of the present invention is to form an insulating film on the surface of a support containing a connecting circuit for connection.

[0012]

According to the above-mentioned means, or because the electrically insulating layer is formed on the surface of the connecting circuit, the insulating property between the adjacent connecting circuits can be sufficiently ensured even with a narrow pitch.

[0013]

Embodiments of the present invention having the same function are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be described.

(Embodiment 1) FIG. 1 is a sectional view showing a circuit connecting method according to a first embodiment of the present invention. An insulating anodic oxide layer 3 is formed on the surface of the take-out electrode 2 when a TFT or the like is formed on the liquid crystal panel. When the resin film 6 is aligned and pressure-bonded, the conductive particles 4 become the anodic oxide layer 3
The lead electrode 1 and the lead-out electrode 2 are electrically connected to reach the lead-out electrode 2 which is difficult to reach. As can be seen from this principle, the conductive particles 4 are preferably relatively hard. In the experiment of the inventor, the anodic oxide layer 3 was formed by using Al for the extraction electrode 2 and the conductive particles 4 of Ni particles were used.

An anodized layer 3 is formed on the surface of the lead-out electrode 2, and the lead 1 and the lead-out electrode 2 are connected by breaking the anodized layer 3 only at the portions necessary for connection. The insulation resistance between the extraction electrodes 2 is very high.

The inventor has also confirmed that an oxide film is formed on the Al surface and the same effect can be obtained by heat-treating the glass substrate 7 on which the extraction electrode 2 is formed instead of anodic oxidation.

(Embodiment 2) For the connection at a narrow pitch, it becomes difficult to align the lead 1 and the take-out electrode 2 with each other. However, in the circuit connecting method of the present invention, FIG.
As shown in Fig. 7, even if the lead 1 and the lead-out electrode 2 are slightly misaligned, there is no problem with the insulation resistance between adjacent ones, and there is a large margin for misalignment at the time of alignment and crimping, which also contributes to stable process It is a great contribution.

(Embodiment 3) FIG. 3 is a sectional view showing a circuit connecting method according to a third embodiment of the present invention. As described in the conventional example, in the TFT liquid crystal panel or the like, the protective film 8 is formed on the glass substrate 7, but in this embodiment, the protective film 8 is connected without providing an opening. In an experiment conducted by the inventor, the conductive particles 4 having a relatively high hardness are used and heated and pressed under a sufficient pressure, so that the conductive particles 4 can break the protective film 8 and reach the extraction electrode 2 to realize an electrical connection. It was At that time, the protective film is a silicon nitride film that is usually used for manufacturing TFTs, and the film thickness is 1000 to 2000Å
Thus, as the conductive particles 4, Ni particles were used as in Example 1.

(Embodiment 4) FIG. 4 is a sectional view showing a circuit connecting method according to a fourth embodiment of the present invention. Before connecting the lead 1 and the extraction electrode 2, the surface of the lead 1 is covered with a protective film 8. In the inventors' experiment, polyurethane resin was used as the material of the protective film 8. When the resin film 6 is aligned and pressure-bonded, the conductive particles 4 penetrate into the protective film 8 and reach the lead 1 to secure the electrical connection between the lead 1 and the extraction electrode 2. As in the case of Example 1, it is desirable to use conductive particles 4 having high hardness.

The anodic oxide layer 3 shown in the above embodiment is used.
It goes without saying that an ideal configuration can be obtained by using the insulating film 8 and the insulating film 8 together.

Although the liquid crystal panel has been described in this embodiment, the contents of the present invention are a multi-chip module in which a multi-pin LSI is TAB mounted on an electronic display device such as a plasma display other than liquid crystal, a ceramic multilayer substrate or a printed wiring board. It can be widely used as a mounting method for electronic components.

[0022]

As is apparent from the above-described embodiments, the present invention provides a protective film on the take-out electrode or the surface of the circuit to ensure the insulation, and breaks the protective film only by the conductive particles at the portions necessary for connection to make the conductive film. Since the structure has good properties, the insulation resistance between adjacent parts can be kept sufficiently high even for a narrow pitch connection. It is possible to break the protective film by using metal particles having a relatively high hardness as the conductive particles.

[Brief description of drawings]

FIG. 1 is a sectional view of a connecting portion in a circuit connecting method according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a connecting portion in a circuit connecting method according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a connecting portion in a circuit connecting method according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a connecting portion in a circuit connecting method according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view of a connection portion in a conventional circuit connection method.

FIG. 6 is a cross-sectional view of a connection portion in a conventional circuit connection method.

FIG. 7 is a cross-sectional view of a connection portion in a conventional circuit connection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead 2 Extraction electrode 3 Anodized layer 4 Conductive particles 5 Adhesive 6 Resin film 7 Glass electrode 8 Protective film 9 Driving IC

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akemi Kawazu 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A method of connecting circuits in which connecting circuits formed on opposite supports are connected to each other by an electrical connecting member, and at least one surface of the support including the connecting circuits is provided. And a circuit connecting method characterized in that an electrically insulating insulating film is provided. 2. The circuit connecting method according to claim 1, wherein at least one of the connecting circuits is surface-treated to form an insulating film. 3. The circuit connecting method according to claim 2, wherein the surface treatment is anodic oxidation. 4. The circuit connecting method according to claim 2, wherein the surface treatment is heat treatment. 5. The circuit connecting method according to claim 2, wherein the surface treatment is vapor deposition of a material other than the connecting circuit. 6. The circuit connecting method according to claim 1, wherein a material other than the connecting circuit is coated on the surface of the support to form an insulating film. 7. The circuit connecting method according to claim 7, wherein an organic polymer material is used for the insulating film. 8. The circuit connecting method according to claim 1, wherein an anisotropic conductive adhesive is used for the electrical connecting member.