JPS61166876A - Anisotropically electrically-conductive adhesive - Google Patents

Abstract

PURPOSE:The titled adhesive for connecting a circuit substrate to a circuit part, etc., capable of linking a narrow pitch electrode without causing short- circuit, obtained by dispersing electrically-conductive powder capable of coming into ohmic contact with a material to be bonded into a thermoplastic resin, etc., and molding the blend into a thin film with a specific thickness. CONSTITUTION:Electrically-conductive powder (preferably indium, gold, carbon, or graphite) capable of coming into ohmic contact with a material to be bonded is dispersed into a thermoplastic resin or a mixture of it and a thermosetting resin and molded into a thin film with 10-100mu, to give the aimed adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an anisotropically conductive adhesive that can be used to connect circuit boards and circuit components.

(Prior Art) Conventionally, when electrically connecting between corresponding electrodes between a plurality of circuit boards and circuit components, the means for doing so is, for example, forming each corresponding electrode in the same shape, And a so-called Elastake connector is sandwiched between both electrodes facing each other.
There is a way to obtain a connection by applying pressure.

Further, as another means, there is a sheet-shaped anisotropic conductive film in which a fibrous conductor is contained in an adhesive.

There is a method in which this sheet is sandwiched between opposing electrodes and then hot-pressed to bring the fibrous conductor into contact with the electrodes to establish continuity (for example, Japanese Patent Laid-Open No. 138881/1981).

(Problems to be Solved by the Invention) With such a conventional configuration, the Elastic Take connector always requires a pressurized state, and there are limits to reducing the dimensions of the Elastic Take connector itself. The facing distance between the circuit board and the circuit components is limited, and it cannot be used for extremely narrow pitch electrodes, for example, 100 μm pitch. In addition, in the case of a sheet-shaped anisotropic conductive film,
Since carbon fibers with a length of about 50 to 1000 μm are used as the fibrous conductor, they cannot be used for narrow pitch electrodes. If the electrode is not in ohmic contact with the electrode, there are problems such as high connection resistance.

The object of the present invention is to solve these problems, and to provide an anisotropically conductive adhesive that allows the use of narrow pitch electrodes and provides good conductivity even when the electrodes are semiconductors.

(Means for Solving the Problems) The anisotropically conductive adhesive of the present invention makes ohmic contact with objects to be adhered in a thermoplastic resin or in a mixture of a thermoplastic resin and a thermosetting resin. It uses a moist conductive powder.

(Function) The anisotropically conductive adhesive configured as described above is fixed onto the electrode to be connected of the first adhered object, which is the circuit board or circuit component, and the second adhered object, which is the circuit board, is fixed onto the electrode to be connected. After aligning the electrodes of the board or circuit components to be connected facing each other, pressure is applied while applying heat. After being depressurized and cooled, the conductive powder is fixed between the pair of electrodes to be connected by the hardened resin, thereby establishing an electrical connection.

At this time, the anisotropic conductive adhesive of the present invention has a content of 10 to 10
Since it is formed in the form of a thin film of 0 μm, it can be easily fixed by placing it on one of the electrodes to be connected and applying heat and pressure, so there is no need to use means such as screen printing. The film with a thickness of 10 to 100μ is 10μ.
This is because if the thickness is less than m, the adhesive strength is insufficient, and if it exceeds 100 μm, poor conductivity will occur.

In addition, by selecting the particle size of the conductive powder sufficiently small, it is possible to
It can also be used with the narrow pitch electrodes described in 1 below without causing short-circuits between the electrodes. Furthermore, by using conductive powder that makes ohmic contact with the object to be adhered, even if the object to be adhered is a semiconductor, it can be directly connected.

(Example) The present invention will be explained based on FIGS. 1 to 3.

FIG. 1 shows the structure of an anisotropically conductive adhesive in an embodiment of the present invention.

In the figure, 1 is an anisotropic conductive adhesive, and the resin components are 50 parts by weight of Epicoat #828 (Shell Chemical Layer) and 50 parts by weight of phenol-modified xylene resin (J-1000 manufactured by Denkou Electric Works).
Parts by weight of the mixture were used, and 1 part by weight of indium powder with a particle size of 0.1 μm was used as the conductive powder. 2 was a release paper, on which the anisotropic conductive adhesive 1 was coated to a thickness of 30 μm and molecularly dried at 85° C. for 60 minutes.

FIGS. 2 and 3 are cross-sectional views showing the configuration of an example of use of the present invention. In the same figure, 3 is a glass substrate, 4 is a Cd
The S (cadmium sulfide) layer is formed in a stripe shape on the glass substrate 3. Reference numeral 5 denotes a flexible substrate, on which a copper foil 6 is formed in the same pattern as the Cd5 layer 4.

Next, the anisotropic conductive adhesive 1 formed into a thin film as described above on the adhered electrode (copper foil 6) of the flexible substrate 5 shown in FIG. 2 is cut into an appropriate size along with the release paper 2. Temporary fixing is performed with the surface of the anisotropic conductive adhesive 1 facing the electrode.

Temperature of temporary fixing is 110℃.

A pressure of 5 kg/d is applied. After temporary fixing, release paper 2
is removed and the positional alignment between the Cd5 layer 4 on the glass substrate 3 and the copper foil 6 on the flexible substrate 5 is performed, and then main pressure bonding is performed. The main crimping is carried out at a temperature of 140℃ and a pressure of 40kg/cd.
Add and perform gluing. FIG. 3 shows the configuration after the main crimping.

As a result, even narrow pitch electrodes can be connected without shorting.
Even though the electrodes were semiconductors, the contact resistance was small.

So far, we have only described examples in which indium is used as a conductive powder to connect CdS as a semiconductor and copper foil. Can be used. Further, although only CdS has been described as a semiconductor, other semiconductors can be used as long as they are capable of making ohmic contact with the conductive powder in the anisotropically conductive adhesive.

(Effects of the Invention) According to the present invention, it is possible to connect even narrow pitch electrodes without causing a short circuit, no mechanical auxiliary pressure or contact means are required after connection, and the electrodes to be adhered are semiconductors. However, if the conductive powder in the anisotropic conductive adhesive is selected to be able to make ohmic contact with the semiconductor, it is effective to obtain good conduction.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of an anisotropically conductive adhesive according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views according to an example of use of the present invention. 1... Anisotropic conductive adhesive, 2... Release paper, 3...
-Glass substrate, 4...CdS layer, 5...Flexible substrate, 6-...Copper foil. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) Conductive powder capable of making ohmic contact with the object to be adhered is dispersed in a thermoplastic resin or a mixture of a thermoplastic resin and a thermosetting resin, and the thickness is 10 to 100 μm.
An anisotropic conductive adhesive characterized by being formed into a thin film of m. (2) The anisotropic conductive adhesive according to claim (1), characterized in that the conductive powder is indium, gold, carbon, or graphite alone or in a mixture.