JPH03132094A - Anisotropic conductive bonding agent connection method - Google Patents

Abstract

PURPOSE:To enhance adhesive power in an exposed part, to enable the printing of a thick film-anisotropic conductive bonding agent and to make a definite connection by heating an anisotropic conductive bonding agent delivered from a printed board to a pad and an anisotropic boding agent transferred to a board and evaporating a diluent in the exposed part. CONSTITUTION:A printed pattern 11 on a printed board 7 is filled with a paste- like anisotropic conductive bonding agent 12 diluted by a diluent. The bonding agent 12 is transferred to pads 13. The pads 13 are heated with a heater 14 on the way to transfer and suspended at the top of the heater 12. The diluent on the exposed surface of the bonding agent 12 is evaporated. In this state, the pads 13 are transferred to the surface of a board 8 and the bonding agent 13 is transferred to the board 8. A dryer 16 is arranged to blow hot air and evaporate the diluent on the exposed surface of the bonding agent 12. After this process, a second board is hot-pressed to the second board by sandwiching the bonding agent. This construction makes it possible to enhance the adhesive power in the exposed part, to print thick film anisotropic bonding agent and to make definite connection as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Field of Industrial Application) The present invention relates to an anisotropic conductive adhesive connection method applied to, for example, connection of substrates incorporated in an IC card.

(Prior Art) Conventionally, an anisotropic conductive adhesive has been used for mechanical coupling involving electrical connection between thin substrates incorporated in IC cards. Usually, screen printing has been mainly applied when printing anisotropic conductive adhesive onto a substrate.

A connection terminal (not shown) made of a conductive pattern is formed near the stepped portion 3 formed by the reinforcing substrate 2.

Then, an anisotropic conductive adhesive is provided on the edge 4 near the stepped portion 3, and the second substrate 5 is connected as shown in FIG.

However, the anisotropic conductive adhesive could not be accurately printed in the vicinity of the stepped portion 3 as described above using the conventional screen printing method.

For this reason, it has been considered to apply the pad printing method to print anisotropic conductive adhesives, but in reality, the film thickness that can be printed with anisotropic conductive adhesives using the pad printing method is only about a few μm. It was thin and difficult to print to a thickness that would be practical.

(Problem A to be Solved by the Invention) Screen printing has generally been used to print anisotropic conductive adhesives on substrates, but when the substrate has a step, etc. It was very difficult to accurately screen print anisotropic conductive adhesive in the vicinity. For this reason, it has been considered to print an anisotropic conductive adhesive using a pad printing method, but this pad printing method has the drawback of not being able to obtain a sufficient film thickness, making it difficult to put it into practical use.

The present invention has been made in view of the above-mentioned problems, and provides an anisotropic conductive adhesive connection method that prints an anisotropic conductive adhesive with a sufficient thickness using a pad printing method to enable a reliable connection. The purpose is to provide

C Structure of the Invention] (Means for Solving the Problems) In the first step, the printed pattern of the printing plate is filled with a paste-like anisotropic conductive adhesive and the pad is pressed against the printing plate, thereby achieving the anisotropic conductive adhesive. The conductive adhesive is transferred to the pad, and in the second step, the anisotropic conductive adhesive transferred to the pad is heated to evaporate the diluent in the exposed portion, and in the third step, the pad is pressed against the first substrate. The anisotropic conductive adhesive is printed on a first substrate, the diluent in the exposed portion of the anisotropic conductive adhesive printed on the first substrate is evaporated in a fourth step, and the anisotropic conductive adhesive is evaporated in a fifth step. An anisotropic conductive adhesive connection method for connecting a second substrate to the first substrate with a conductive adhesive interposed therebetween.

(Function) The anisotropic conductive adhesive transferred to the pad in the first step is transferred to the second step.
By heating in the process and evaporating the diluent in the exposed parts, the adhesive strength of the exposed parts is made higher than the adhesive strength of the anisotropic conductive adhesive to the pad side. By printing on the first substrate in this state in the third step, the image is reliably transferred to the first substrate. By heating the exposed portion of the anisotropic conductive adhesive transferred to the first substrate in the fourth step, the adhesive strength of this exposed portion is increased and the second substrate is connected in the fifth step.

As a result, the adhesive strength of the area to which the anisotropic conductive adhesive is transferred increases in each step, so printing can be reliably performed even with a thick anisotropic conductive adhesive that was previously impossible.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 3. What is shown in FIG. 1 is a schematic diagram of a pad printing device 6, together showing its printing process.

The pad printing device 6 shown in the figure includes a table 10 on which a printing plate 7 and a jig 9 for holding a first substrate 8 are placed. A groove-shaped print pattern 11 is formed on the printing plate 7 . The depth of this print pattern 11 is set to be large. In other words, the anisotropic conductive adhesive 12 is formed with a larger thickness than that of an anisotropic conductive adhesive that is generally pad printed. The anisotropic conductive adhesive 12 having this thickness cannot be reliably printed using a pad printing apparatus having a conventional structure.

A pad 13 is provided on the top of the table 10 and is movable between the printing plate 7 and the first substrate 8 and can be raised and lowered. Further, between the printing plate 7 and the first substrate 8, a heating means is provided for heating the anisotropic conductive adhesive 12 transferred to the pad 13 by infrared radiation in the middle of the movement of the pad 13. heater 1
4 is provided. Further, a dryer 16 is provided as a heating means for supplying, for example, hot air to a position on the first substrate 8 where the anisotropic conductive adhesive 12 is to be printed.

The pad printing device 6 configured as described above allows the first
Each step of connecting the substrate 8 and the second substrate 17 will be explained.

First, a paste-like anisotropic conductive adhesive 1 diluted with a diluent is applied to the print pattern 11 of the printing plate 7.
2 is satisfied. After this, the pad 13 is pressed down onto the printing plate 7. Then, the anisotropic conductive adhesive 12 is transferred to the pad 13 by raising the rosette 13. This completes the first step.

Thereafter, the pad 13 is moved toward the first substrate 8, but in the middle of the movement, the pad 13 is stopped above the heated heater 14. Here, the anisotropic conductive adhesive 12 transferred to the pad 13 is heated by the heater 14, and the diluent on the exposed surface of the anisotropic conductive adhesive 12 is evaporated.

As a result, the adhesive strength of the exposed portion of the anisotropic conductive adhesive 12 becomes higher than that of the portion attached to the pad 13. This completes the second step. Although the pad 13 is stopped during heating, it is also possible to arrange heaters 14 along the movement range of the pad 13 and heat the pad 13 while it is moving.

In this state, the pad 13 is moved to the top of the first substrate 8, and is lowered and pressed against the first IX board 8. Thereafter, by raising the pad 13, the anisotropic conductive adhesive 13 is transferred onto the first substrate 8. That is, since the surface whose adhesive strength has been increased in the second step is transferred to the first substrate 8, the anisotropic conductive adhesive 12 is applied to the pad 1.
3 to the first substrate 8 side. This allows the third
The process ends.

The anisotropic conductive adhesive 12 transferred to the first substrate 8 is transferred to the pad 13 with the weaker adhesive surface exposed. Therefore, by blowing hot air using the dryer 16, the diluent in the exposed portion of the anisotropic conductive adhesive 12 is evaporated and the adhesive strength is increased.

This completes the fourth step.

Then, the second substrate 1 is placed with the anisotropic conductive adhesive 12 in between.
7 is bonded to the first substrate 8 and bonded under heat and pressure. As a result, the anisotropic conductive adhesive 12 is melted and flows into every corner, reliably connecting the first substrate 17 and the second substrate electrically and mechanically. This completes the fifth step.

According to the process explained above, the anisotropic conductive adhesive 12 has a large film thickness that could not be pad printed with the conventional structure.
can now be printed reliably.

In other words, by increasing the adhesion of the exposed portion of the anisotropic conductive adhesive 12 that has moved from the printing plate 7 to the pad 13, the anisotropic conductive adhesive 12 can be reliably moved from the pad 13 to the first substrate 8. . And in the conventional method, pad 1
This makes it possible to reliably transfer the thick anisotropic conductive adhesive 12, which was extremely difficult to transfer from the first substrate 3 to the first substrate 8. Specifically, with the conventional pad printing method, only a film thickness of about several μm could be transferred, but according to the above example, the anisotropic conductive adhesive 12 with a film thickness of 10 to 30 μm was transferred.
can be transferred reliably.

As a result, it is possible to transfer the anisotropic conductive adhesive 12 of the required thickness even to the first substrate 8 on which the step portion 3 is formed by the reinforcing substrate 2 as shown in FIG. Reliable connection of the second board 17 can be realized.

Note that the present invention is not limited to the above embodiment. For example, the heater used to evaporate the diluent of the anisotropic conductive adhesive 12 may be a heater that generates hot air or infrared rays, and its type is not particularly limited.

[Effect of the invention] By heating the exposed portion of the anisotropic conductive adhesive passed from the printing plate to the pad and thereby evaporating the diluent of the anisotropic conductive adhesive, the adhesive strength of the exposed portion is increased. increase,
By ensuring the transfer of the anisotropic conductive adhesive to the first substrate, pad printing of the anisotropic conductive adhesive with a large film thickness, which was previously impossible, is possible, and the first and second substrates are In addition to obtaining the connection strength required for the connection, the anisotropic conductive adhesive can be reliably transferred from the pad to the first substrate during mass production, and stable productivity can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a pad printing apparatus shown together with a pad printing process of an anisotropic conductive adhesive according to an embodiment of the present invention, and FIG. 2 shows a first substrate on which the embodiment of the present invention is applied. A perspective view and FIG. 3 are perspective views showing a state in which a second substrate is connected to a first substrate, which is an object of the present invention. 7... Printing plate, 8... First substrate, 11... Print and pattern, 12... Anisotropic conductive adhesive, 13...
Pad, 14... Heater, 16... Dryer 17... Second board.

Claims (1)

[Claims] The groove-shaped print pattern formed on the printing plate is filled with a pasty anisotropic conductive adhesive whose viscosity is adjusted to a predetermined value using a diluent, and the anisotropic conductive adhesive is applied by pressing a pad against the printing plate. a first step of transferring the agent to the pad; a second step of heating the anisotropic conductive adhesive transferred to the pad in the first step to evaporate the diluent in the exposed portion;
A third step of transferring the anisotropic conductive adhesive to the first substrate by pressing the pad against the first substrate, and heating the anisotropic conductive adhesive transferred to the first substrate to remove the exposed portion. An anisotropic conductive adhesive connection characterized by comprising a fourth step of evaporating a diluent, and a fifth step of connecting a second substrate to the first substrate with the anisotropic conductive adhesive interposed therebetween. Method.