JPH0546170Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a circuit connection tape with excellent moisture resistance, and more specifically, a circuit connection tape suitable for establishing a conductive connection between connection terminals arranged opposite each other. Regarding.

(Prior art) As a circuit connecting member, a predetermined amount of conductive filler is contained in an insulating adhesive, which is inserted between the circuits to be connected and heated or pressed in the thickness direction of the circuit. Tapes for connecting microcircuits are known that can provide both electrical conductivity and insulation between adjacent circuits.

There have also been attempts to obtain circuit connections without the addition of conductive fillers, as seen in Japanese Patent Publication No. 46-43732, and further attempts have been made to utilize the unevenness of the adhesive tape base material to create conductivity in the thickness direction of the adhesive. A proposal to connect circuits by obtaining the above information is also found in Japanese Patent Publication No. 47-51798.

(Problems to be solved by the invention) In order to use the above-mentioned circuit connection members for mounting electronic components that require high reliability, they must be one step further in moisture (water) resistance. .

In other words, the adhesive used for these circuit connection members needs to have a high polarity in order to improve its adhesion to conductor circuits.
When the polarity of the adhesive is increased, it tends to become hygroscopic, resulting in a decrease in moisture resistance.

To this end, efforts have been made to adjust the hygroscopicity of the adhesive by examining its composition and to improve its moisture-resistant adhesion to the circuit interface, but no fundamental solution has been reached.

If the moisture resistance of the connection member is insufficient, problems such as poor conductivity due to the infiltration of water or water vapor into the connection interface and acceleration of corrosion of the circuit material will occur.

For this reason, in practice, after making the circuit connections,
This is countered by providing a coating layer around the connection area using a protective material such as silicone or epoxy (generally called a moisture-proof coat).
Formation of these coating layers involves, for example, weighing, coating,
Each process such as drying and curing requires a great deal of labor and time, and in particular, forming a coating layer of a certain desired thickness around circuit connections with large irregularities requires experienced skills.

The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide an adhesive tape for circuit connection that enables connection of circuits with excellent moisture resistance.

(Means for Solving the Problem) That is, the present invention provides an adhesive tape for circuit connection made of a conductive adhesive, in which surface tension is applied to the end face of at least one adhesive layer on both sides of the tape.
It is characterized by being coated with a pressure-sensitive fluid material of 35 dyne/cm or less.

The present invention will be described below with reference to the drawings showing embodiments.

1 to 3 are conceptual diagrams showing the structure of the adhesive tape according to the present invention.

In Figures 1 to 3, adhesive tape 1 is made by dispersing conductive particles in an insulating adhesive component, and is preferably in the form of a sheet or tape, and requires pressure when connecting circuits. . Moisture barrier layer 2
is pressure-sensitive fluid and has a surface tension of 35dyne/
It is a substance of less than cm. 3 is a base separator.

The moisture-proof layer 2 flows due to the pressure when the circuit is connected and covers the circuit ends, thereby preventing moisture from entering the connection parts.

Substances having a surface tension of 35 dyne/cm or less include, for example, silicone-based materials, fluorine-based materials, olefin-based materials, etc., and they can be appropriately selected from these materials or used in combination. Surface tension can be measured by Duneuulli's hanging ring method when the moisture barrier layer 2 is a liquid material, and by Zisman's critical surface tension method when it is a solid material.
The film wetness test method according to 6768 can also be adopted in accordance with the former.

The surface tension obtained by the above method at 25℃ is
Materials with a density of 35 dyne/cm or less can be applied.

In general, the lower the surface tension, the greater the water repellency, so it is suitable as a moisture-proof coating, and preferably
A material having a surface tension of 33 dyne/cm or less, more preferably 30 dyne/cm or less can be used.

These moisture-proof layers 2 preferably have adhesive properties to circuits and spaces, and for this purpose, coupling agents such as silane, titanium, and aluminum, chelating agents, and adhesion enhancers such as titanium-containing compounds are used. , it is also possible to contain polar groups such as carboxylic acid groups and hydroxyl groups.

The moisture-proof layer 2 may be formed by coating the side surface of a tape-shaped roll as shown in FIG. 3 with the pressure-sensitive fluid material by spraying or brushing. A very simple method for obtaining the composition is to cut the tape into predetermined dimensions by continuously supplying a liquid or heat-molten material to the cutting blade that will form the moisture-proof layer while cutting the tape.

The moisture-proof layer 2 may be formed on the end face of at least one adhesive layer on both sides of the adhesive tape 1 as shown in FIG. It is preferable to form.

The separator 3 is used as a support for the adhesive tape 1 if necessary, and is generally paper or plastic film treated with a release agent.

FIG. 4 is a schematic diagram showing a connection part of a circuit using the adhesive tape according to the present invention.

By interposing the connecting tape of the present invention between the circuits 4 and 4' and applying pressure or heating, the adhesive tape 1 softens and flows to connect the circuits 4 and 4'.

At this time, the moisture-proof layer 2 also flows in substantially the same manner as the adhesive tape 1, forming the moisture-proof layer 2 at the end of the adhesive tape.

It is also preferable to provide a curing process using heat, light, electron beam, etc. after the circuit is connected, since this provides an excellent moisture-proof coating layer. In other words, when forming the moisture barrier layer on the connecting member and when connecting the circuit, it is preferable that the moisture barrier layer is in a liquid state or a low molecular weight state for the sake of work and penetration into the circuit surface, but after the circuit is connected, the moisture barrier layer increases in molecular weight and aggregates. This is due to the ability to apply force to improve adhesion to the circuit.

(Effects of the invention) As detailed above, the present invention provides a moisture-proof layer at the end of the connection member layer of the circuit, making it possible to configure the moisture-proof coating layer in the circuit simply by connecting the circuit. It became.

The moisture-proof layer is made of a substance with low surface tension and has water repellency, so that moisture and moisture infiltration into the connection portion are reduced, and the moisture resistance reliability of the circuit connection portion can be significantly improved.

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views showing one layer of the adhesive tape according to the present invention. FIG. 3 is a perspective view showing an example of a rolled body of adhesive tape according to the present invention. Fourth
The figure is a perspective view showing a circuit connection part using the adhesive tape according to the present invention. Explanation of symbols, 1...Adhesive tape, 2...Moisture-proof layer, 3...Separator, 4,4'...Circuit terminal,
5, 5'...Circuit board.

Claims (1)

[Scope of utility model registration request] An adhesive tape for circuit connection made of a conductive adhesive, characterized in that the end face of at least one adhesive layer on both sides of the tape is coated with a pressure-sensitive fluid substance having a surface tension of 35 dyne/cm or less. Adhesive tape for circuit connections.