JP2000183518A - Method for connecting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for connecting a substrate for preventing the occurrence of migration by reducing air bubbles in the connecting part of a first substrate with a second substrate, and for improving the strength of the connecting part, and for facilitating countermeasures to the integration into narrow pitches of the electrode terminals of the first substrate and the second substrate. SOLUTION: This is a substrate connecting method for electrically connecting an electrode terminal 3b of a first substrate 3 with an electrode terminal 9a of a second substrate 9. This method comprises an applying step for applying adhesive 7, in which conductive particles 7a are included with paste-shape insulating material whose viscosity is low as the base materials to the electrode terminal of at least one of each substrates 3 and 9 and a pressing step for heating electrode terminals 3b and 9a of each first substrate 3 and second substrate 9 in a state such that the adhesive 7 is interposed between them, and for mutually pressure contact electrode terminals of the first substrate 3 and the second substrate 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a first substrate and a second substrate.
The present invention relates to a board connection method for connecting electrode terminals of a board.

[0002]

2. Description of the Related Art In recent years, electronic devices have built-in electronic circuits having various functions. Such an electronic circuit is generally configured by connecting a plurality of wiring boards (hereinafter simply referred to as boards) for each function or the like. Each substrate is, for example, an FPC (Flexible Printed Cir.).
The connection is made by a flexible printed circuit board (flexible circuit board) called a circuit (circuit). The flexible substrate is for electrically connecting, for example, a substrate having a wiring formed on a glass panel (abbreviated as a glass panel) and a printed circuit board. The following description is based on the premise that this flexible substrate is connected to a glass panel as an example.

FIG. 5A is a cross-sectional view showing a flexible substrate 3 and a glass panel 9 connected by a conventional substrate connection method, and FIG. 5B is a sectional view of the conventional flexible substrate shown in FIG. FIG. 4 is a partial cross-sectional view when the state of the substrate is viewed from a Z direction. The electronic circuit 100 mainly includes, for example, a printed wiring board 11 (PWB (Printing
iting Board)), a flexible substrate 3 and a glass panel 9. The flexible substrate 3 is provided with, for example, predetermined electrode terminals at both ends thereof, and is connected to the respective electrode terminals provided on the printed wiring board 11 and the glass panel 9 to make them electrically conductive.

In the following, as an example, a flexible substrate 3
And the glass panel 9 will be described. When the electrode terminals of the flexible substrate 3 and the glass panel 9 are connected to each other, they are pressure-bonded via an anisotropic conductive film 107 for electrically connecting them, as shown in a portion W of FIG. The electrode terminals of the flexible substrate 3 and the glass panel 9 are covered with the coating agent 5 and are insulated from other parts. Here, the anisotropic conductive film 107 (ACF (Anisotropic Condu)
active film)) is a film-like insulator, for example, an epoxy resin as a base material, in which conductive particles (particles 107a) are dispersed in a connection resin, and a conductive portion sandwiching the particles 107a is conductive. Other parts are insulated. Anisotropic conductive film 107
Is made of, for example, a hard anisotropic conductive material.

The flexible substrate 3 has predetermined electrodes 3b, 3b, 3b provided on a base film 3a as shown in FIG. When the flexible substrate 3 is connected to the glass panel 9, the electrodes 3 b, 3 b, 3 b are connected to 9 a, 9 a, 9 a provided on the glass panel 9 via the conductive particles 107 a of the anisotropic conductive film 107. To make electrical contact.

Next, the manner in which the flexible substrate 3 and the glass panel 9 are connected by a conventional substrate connection method will be described with reference to FIGS. FIG. 6 (A)
FIG. 6B is an enlarged view illustrating an example of a method of manufacturing the portion W in FIG. 5, and FIG.
FIG. 7 is a side view when the flexible substrate 3 and the glass panel 9 are viewed from the S direction in FIG. 6 (A) and 6
The difference from (B) is the same in FIGS.

As shown in FIGS. 6A and 6B, an anisotropic conductive film 107 containing conductive particles 107a is disposed between the flexible substrate 3 and the glass panel 9.

[0008] Flexible substrate 3 and glass panel 9
After the alignment is performed as shown in FIGS. 7A and 7B, temporary attachment (temporary attachment) is performed on the anisotropic conductive film 107. At this time, the anisotropic conductive film 1
Air 19 as air bubbles or the like is formed between the substrate 7 and the flexible substrate 3 and between the anisotropic conductive film 107 and the glass panel 9.

In this state, as shown in FIGS. 8A and 8B, the anisotropic conductive film 10 is
The flexible substrate 3 and the glass panel 9 are thermocompression-bonded while sandwiching the. At this time, the flexible substrate 3
Further, since the hard cover film 17 is provided at the connection portion of the glass panel 9, air 19 is generated as shown in FIGS. 8A and 8B.

In this state, the flexible substrate 3 is further moved by the thermocompression bonding head 15 as shown in FIGS.
When the glass panel 9 is pressed, the air 19 remains so as to be held by the electrodes 3b and 9b at the connection portion.

[0011]

SUMMARY OF THE INVENTION
Cannot be completely removed from the arrangement and structure of the base film 3a and the cover film 107 of the flexible substrate 3. If the air 19 remains on the anisotropic conductive film 107, for example, water vapor may penetrate into the inner peripheral portion of the air 19 to form a water film, and migration may occur. Here, migration (metal migration) generally means that when a voltage is applied between two metals, metal ions move from one metal to the other metal along a conductive path. To indicate
There are cases where metal ions move on the surface of the insulator and cases where they move inside the insulator. That is, the term “migration” refers to a phenomenon in which such a phenomenon progresses and may cause insulation deterioration or short circuit of the insulator. Further, since a water film is formed on the inner peripheral portion of the air 19, the anisotropic conductive film 10 is formed.
In some cases, the dielectric strength and strength of 7 may decrease. For this reason, it is necessary to reduce the air 19 in order to reduce the pitch between the electrodes in the flexible substrate 3 and the glass panel 9 in the future.

Therefore, the present invention solves the above-mentioned problem, and reduces the bubbles in the bonding portion between the first substrate and the second substrate so that migration does not occur and the strength of the connecting portion can be improved. It is an object of the present invention to provide a substrate connection method that can cope with a narrow pitch of electrode terminals of each of a substrate and a second substrate.

[0013]

According to the present invention, there is provided a method of connecting a substrate for electrically connecting an electrode terminal of a first substrate to an electrode terminal of a second substrate. An application step of applying an adhesive containing conductive particles to at least one of the electrode terminals of the respective substrates using a low-viscosity paste-like insulating material as a base material, and the first substrate and the second substrate, respectively. And a pressure bonding step of pressing the electrode terminals of the first substrate and the second substrate with each other by heating while the adhesive is sandwiched by the electrode terminals of the first and second substrates.

According to the above configuration, in order to electrically connect the electrode terminals of the first substrate and the electrode terminals of the second substrate,
At least one electrode terminal of each of the substrates is coated with an adhesive containing conductive particles using a low-viscosity paste-like insulating material as a base material, and the electrodes of the first substrate and the second substrate are respectively applied. Heating is performed with the adhesive sandwiched between the terminals, and the electrode terminals of the first substrate and the second substrate are pressed together.

[0015]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

In the following description, "anisotropic" means that conductive particles are dispersed in a connecting resin, a conductive portion sandwiching the particles is conductive, and the other portions are insulated. Shall be shown. FIG. 1A is a cross-sectional view showing a configuration example of a flexible substrate 3 and a glass panel 9 connected by a substrate connection method as a preferred embodiment of the present invention, and FIG. (A)
FIG. 2 is a partial cross-sectional view of the state of the flexible substrate 3 and the glass panel 9 when viewed from the Z direction. The electronic circuit 1 mainly includes, for example, a printed wiring board 11 (PWB (Printi
ng Writing Board)), flexible substrate 3 (flexible printed circuit board) and glass panel 9
Having. The flexible substrate 3 is provided with, for example, predetermined electrode terminals at both ends thereof.
And the respective electrode terminals provided on the glass panel 9 to make them electrically conductive. The flexible substrate 3 is, for example, an FPC (Flexible Print).
ed Circuit).

In the following, as an example, the flexible substrate 3
And the glass panel 9 will be described. When the electrode terminals of the flexible substrate 3 and the glass panel 9 are connected to each other, an anisotropic conductive member 7 (low-viscosity paste-like insulating material) for electrically connecting the two as shown in a portion W of FIG. It is connected by pressure bonding with an adhesive having conductive particles inside the member). The electrode terminals of the flexible substrate 3 and the glass panel 9 are covered with the coating agent 5 and are insulated from other parts. Here, the anisotropic conductive member 7
Is an adhesive based on, for example, epoxy as an insulator having a low viscosity (eg, about 150 Pa · s), and particles 7a (conductive particles) having conductivity are dispersed in the base. The conductive portion sandwiching the conductive particles 7a is conductive, and the other portions are insulated.

The flexible substrate 3 has predetermined electrodes 3b, 3b, 3b provided on a base film 3a as shown in FIG. When the flexible substrate 3 is connected to the glass panel 9, the electrodes 3 b, 3 b, 3 b are connected to 9 a, 9 a, 9 a provided on the glass panel 9 via the conductive particles 7 a of the anisotropic conductive member 7. To make electrical contact.

Next, how the flexible substrate 3 and the glass panel 9 are connected by the above-described substrate connection method will be described with reference to FIGS. FIG. 2 (A)
FIG. 2B is an enlarged view showing an example of a method for manufacturing the portion W of FIG. 1, and FIG. 2B is a diagram showing the anisotropic conductive member 7, the flexible substrate 3, and the glass panel 9 of FIG. It is a side view when seen from S direction. The difference between FIG. 2A and FIG. 2B is the same in FIGS.

Application Step An anisotropic conductive member 7 containing conductive particles 7a as shown in FIGS. 2A and 2B is provided on at least one of the flexible substrate 3 and the glass panel 9. The coating is performed by the coating unit 13. Here, the anisotropic conductive member 7
As a coating method, various coating methods such as a printing method and a dispensing method can be adopted.

Crimping Step The flexible substrate 3 and the glass panel 9 are shown in FIG.
After the alignment is performed as shown in (B) and (B), temporary attachment is performed on the anisotropic conductive member 7. At this time, since the viscosity of the anisotropic conductive member 7 is low and the anisotropic conductive member 7 is widely applied to the surface between the flexible substrate 3 and the glass panel 9, air 19 as air bubbles or the like is formed. Not done.

In this state, as shown in FIGS. 4A and 4B, the flexible substrate 3 and the glass panel 9 are heated and pressed by the thermocompression bonding head 15 with the anisotropic conductive member 7 sandwiched therebetween. . At this time, a hard cover film 17 is provided at a connection portion between the flexible substrate 3 and the glass panel 9, but air 19 flows from the anisotropic conductive member 7 as shown in FIGS. Released. Therefore, the air 19 is not formed in the anisotropic conductive member 7 unlike the related art.

In this state, as shown in FIGS. 9A and 9B, the flexible substrate 3 is further moved by the thermocompression bonding head 15.
When the glass panel 9 is pressed, the cover film 17 is pressed.
The deformation is different between the place where exists and the place where it does not exist. Then, the electrodes 3b, 3b, 3
b is electrically connected to the electrodes 9a, 9a, 9a of the glass panel 9 by crushing the conductive particles 7a of the anisotropic conductive member 7. In places where the conductive particles 7a are not crushed, conduction between the electrodes is reliably insulated.

According to the embodiment of the present invention, the electrode terminals 3b, 3b, 3b of the flexible substrate 3 and the glass panel 9
In order to electrically connect to the electrode terminals 9a, at least one of the flexible substrate 3 and the glass panel 9 contains conductive particles 7a using a low-viscosity paste-like insulating material as a base material. The anisotropic conductive member 7 is applied and heated while the anisotropic conductive member 7 is sandwiched between the electrode terminals 3b and 9a of the flexible substrate 3 and the glass panel 9, respectively. As described above, according to the board connecting method of the present embodiment, the terminals 3b and 9a are bonded to each other by crimping, so that migration is not generated by reducing bubbles in the bonded portion between the flexible substrate 3 and the glass panel 9, and thus the connecting portion is not bonded. It is possible to improve the strength and to cope with the narrow pitch of the electrode terminals 3b and 9a of the flexible substrate 3 and the glass panel 9, respectively. Kill.

The present invention is not limited to the above embodiment. In the above description, the board connection method as a preferred embodiment of the present invention is described as being applied to the connection between the flexible board 3 and the glass panel 9.
It is needless to say that the present invention can be applied to the connection with 1. Further, the substrate connection method as a preferred embodiment of the present invention can be applied to other substrates.

[0026]

As described above, according to the present invention,
By reducing bubbles in the bonding portion between the first substrate and the second substrate, migration does not occur, the strength of the connection portion can be improved, and the pitch of the electrode terminals of the first substrate and the second substrate can be reduced. Can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration example of a flexible substrate and a glass panel connected by a substrate connection method as a preferred embodiment of the present invention.

FIG. 2 is an enlarged view showing an example of a method for manufacturing the portion W of FIG.

FIG. 3 is an enlarged view showing an example of a method for manufacturing the portion W of FIG.

FIG. 4 is an enlarged view showing an example of a method for manufacturing the portion W of FIG.

FIG. 5 is a view showing a flexible substrate 3 and a glass panel 9 connected by a conventional substrate connection method.

FIG. 6 is an enlarged view showing an example of a method for manufacturing the portion W of FIG.

FIG. 7 is an enlarged view showing an example of a method for manufacturing the portion W of FIG.

FIG. 8 is an enlarged view showing an example of a method for manufacturing the part W of FIG.

FIG. 9 is an enlarged view showing an example of a method for manufacturing the portion W of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electronic circuit, 3 ... Flexible board (1st electrode), 3a ... Base film, 3b ... Electrode (electrode terminal), 7 ... Anisotropic conductive member (Low viscosity paste) Adhesive having conductive particles in a cylindrical insulating member), 7a
..Particles (conductive particles) 9 Glass panel (second electrode), 9a Electrode (electrode terminal), 11a Electrode (electrode terminal)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masakazu Nakata 1 in Sakazaki, Sakazaki, Koda-cho, Nada-gun, Aichi Prefecture Inside Sony Koda Co., Ltd. No. 325 Sony Naka Nitta Co., Ltd. F term (reference) 4J040 JA05 JB10 KA03 KA32 LA01 LA09 MA05 MB05 NA20 PA30 PA33 5E077 BB32 CC06 DD03 GG29 JJ30 5E344 AA02 BB03 BB04 CD02 CD04 DD06 EE30

Claims (5)

[Claims] 1. A substrate connecting method for electrically connecting an electrode terminal of a first substrate and an electrode terminal of a second substrate, wherein at least one of the substrate terminals has a low viscosity. An application step of applying an adhesive containing conductive particles using the paste-like insulating material as a base material, and heating the adhesive while sandwiching the adhesive between electrode terminals of the first substrate and the second substrate. And a crimping step of crimping the electrode terminals of the first substrate and the second substrate together. 2. The substrate connecting method according to claim 1, wherein the applying step applies the adhesive by a printing method. 3. The method according to claim 1, wherein the applying step applies the adhesive by a dispensing method. 4. The method according to claim 1, wherein the insulating material is a material having anisotropic viscosity. 5. The board connection method according to claim 1, wherein at least one of the boards is a flexible printed board.