JPH03132095A - Anisotropic conductive bonding agent connection structure and its connection method - Google Patents

Abstract

PURPOSE:To fill an anisotropic conductive bonding agent to section without a connecting terminal satisfactorily and hence improve adhesive strength by increasing the film thickness of a part located outside the array direction of connection terminals for an anisotropic conductive bonding agent which connects a plurality of connection terminals arrayed in one direction. CONSTITUTION:An anisotropic conductive bonding agent 13 is transferred to a board 11 where conductive patter-based connection terminals 12 are arrayed. The transfer of the bonding agent 13 allows pad print to form the increased film thickness of the end 13a of the bonding agent 13. By this, the board 11 and a board 15 are hot-pressed and bonded with the bonding agent 13 sandwiched between. The outer parts of terminals 12 and 16 are filled with the bonding agent 13, which connects both the terminals 12 and 16 electrically while the board 11 is connected with the board 15 physically. It is therefore, possible to obtain high bond strength and improve durability 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 structure applied to the manufacture of micro-sized electronic circuit devices such as IC cards.

(Prior Art) The terminal connection of an ultra-small electronic circuit such as an IC card has a structure as shown in FIGS. 8 and 9. On one side of the first substrate 1 shown in the figure, a plurality of first connection terminals 2 made of a conductive pattern are arranged in one direction.

Further, the second connecting terminal 3 to be connected to the first connecting terminal 2 consists of a conductive pattern formed on one side of the second substrate 4, and is electrically connected to the first connecting terminal 2 by an anisotropic conductive adhesive 5. physically and mechanically connected.

A sheet of this anisotropic conductive adhesive 5 is attached, for example, to the upper part of the first substrate 1, and the second substrate 4 is thermopressured with the sheet of anisotropic conductive adhesive 5 sandwiched therebetween. As a result, the anisotropic conductive adhesive 5 is temporarily melted and
The substrate 1 and the second substrate 4 are physically joined, and the first connection terminal 2 and the second connection terminal 3 are electrically and physically connected.

Further, as another method of providing the anisotropic conductive adhesive 5,
There is a method of pad printing the paste-like anisotropic conductive adhesive 5. This is done as shown in FIG. Here, to explain the outline of the pad printing device 6, there is a printing plate 7 having a groove-shaped print pattern 7a of anisotropic conductive adhesive 5, and a first printing plate 7 adjacent to the printing plate 7.
It is provided with a substrate support stand 8 that supports the substrate 1, and a pad 9 that reciprocates between the printing plate 7 and the substrate support stand 8 and moves up and down between a position in which it comes into pressure contact with each of them and a movement position.

The process of printing the anisotropic conductive adhesive 5 using the pad printing device 6 will be described below. First, a vest-shaped anisotropic conductive adhesive 5 is poured onto the print pattern 7a of the printing plate 7 to form it. The pad 9 is lowered onto the printing plate 7↓, the anisotropic conductive adhesive 5 formed by the print pattern 7a is transferred onto the surface of the pad 9, and then raised. In this state, the pad 9 is moved above the support stand 8 and lowered onto the first substrate 1 to transfer the anisotropic conductive adhesive 5 to the first connection terminal 2 on the first substrate 1. The state in which this anisotropic conductive adhesive 5 is transferred to the first substrate 1 is as shown in FIG. By thermocompression bonding the second substrate 4 to the first substrate 1, the anisotropic conductive adhesive 5 temporarily melts and bonds both. Then, the first connecting terminal 2 and the second connecting terminal 3 are electrically connected.

Connections made by the two methods described above result in a connection structure as shown in FIG. 9. Such a connection structure creates a non-connection part 10 where the anisotropic conductive adhesive 5 is not bonded between the substrates 1 and 4 at the ends of the connection terminals 2 and 3 in the arrangement direction. Met.

If the non-contact portion 10 is formed, the physical strength of the bond between the substrates 1 and 4 will be reduced, and this will lead to a shortened lifespan, especially in devices that require durability against deformation, such as IC cards.

For this reason, a connection structure shown in Japanese Unexamined Patent Publication No. 62-20396 has been proposed. In this method, the connecting terminals on the end side are formed in a dummy pattern, and a dummy terminal which is not necessary for practical use is formed and connected, thereby ensuring the bonding on the end side.

However, since such dummy terminals are essentially unnecessary, they lead to an increase in the size of the electronic circuit, which causes problems in terms of space efficiency in devices aiming for high-density packaging.

(Problem to be Solved by the Invention) In an anisotropic conductive adhesive connection structure, boards on the end sides in the arrangement direction of a plurality of connection terminals are not bonded together due to insufficient anisotropic conductive adhesive. It was easy to form parts, and the bond strength was low. For this reason, it has been proposed to obtain bonding strength by forming dummy terminals at the ends in the arrangement direction of the connection terminals, but this reduces space efficiency in devices aiming for high-density packaging.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an anisotropic conductive adhesive connection structure that can increase bonding strength while obtaining the same space efficiency of conventional electronic circuits. .

[Structure of the Invention] (Means for Solving the Problems) (1) A plurality of first connection terminals are provided in an array on a first substrate, and an anisotropic conductive adhesive is provided above the first connection terminals, A second substrate is provided, in which the film thickness of the anisotropic conductive adhesive is increased corresponding to the outer side in the arrangement direction of the first connecting terminals, and a plurality of second connecting terminals are formed respectively corresponding to the first connecting terminals. , the second substrate is physically connected to the first substrate with the anisotropic conductive adhesive interposed therebetween, and the second vC connection terminal is electrically connected to the plurality of first connection terminals. Conductive adhesive connection structure.

(2) In the first step, a strip-shaped first anisotropic conductive adhesive is pad printed along the arrangement direction of the first connection terminals of the first substrate, and in the second step, the first anisotropic conductive adhesive is pad printed. A second anisotropic conductive adhesive is pad printed to overlap a portion corresponding to the outside in the arrangement direction of the first connection terminal, and in a third step, the first anisotropic conductive adhesive is applied to the first substrate. An anisotropic conductive adhesive connection method of bonding a second substrate on which a second connection terminal corresponding to the first connection terminal is formed by thermocompression with a second anisotropic conductive adhesive sandwiched therebetween.

(Function) (1) By increasing the film thickness of the anisotropic conductive adhesive corresponding to the outer parts of the first connection terminal and the second connection terminal in the arrangement direction of each other, the thickness of the anisotropic conductive adhesive is increased. It is possible to prevent an unconnected portion from being formed between the first substrate and the second substrate corresponding to the outside. This can improve the bonding strength between the substrates.

(2> Pad printing a strip-shaped first anisotropic conductive adhesive along the arrangement direction of the first connection terminals, and further outside the first anisotropic conductive adhesive in the arrangement direction of the first connection terminals. By pad printing the second anisotropic conductive adhesive on the portion corresponding to the area, a film thickness that cannot be obtained by normal one-time pad printing can be obtained.

(Example) A first example of the present invention will be described with reference to FIGS. 1 to 3. A first connection terminal 12 made of a conductive pattern is formed on one side of the first substrate 11 shown in the figure. A plurality of the first connecting terminals 12 are arranged in one direction, and an anisotropic conductive adhesive 13 shaped like a band is transferred onto the upper part of the first connecting terminals 12.

This anisotropic conductive adhesive 13 is formed by pad printing the anisotropic conductive adhesive 13 made into a paste. Here, the print pattern 14a of the printing plate 14
The part corresponding to the range where the first connection terminals 12 are arranged is formed with the same film thickness as the conventional one, and the film thickness is reduced at the end part 14b corresponding to the outside of the range where the first connection terminals 12 are arranged. It is deeply formed to increase.

The anisotropic conductive adhesive 13 formed by the printed pattern 14a thus formed is thicker at the end portion 13a.

Further, a second substrate 15 is bonded to the first substrate 11 using the anisotropic conductive adhesive 13. This 22nd! Board 1
A plurality of second connection terminals 16 made of a conductive pattern are formed on one side of 5, and these second connection terminals 16 are arranged so as to correspond to the first connection terminals 12.

The first substrate 11 and the second substrate 15 are bonded by thermocompression with the anisotropic conductive adhesive 13 in between.

As a result, the first connection terminal 12 and the second connection terminal 16
are electrically connected to each other, and the first substrate 11 and second substrate 15 are physically connected to each other.

The portions of the first substrate 11 and the second u-board 15 located outside the connection terminals 12.16 are filled with the anisotropic conductive adhesive 13. It is joined with the same strength as the part where No. 16 is provided. In other words, by increasing the thickness of the anisotropic conductive adhesive 13 on the end side, it is possible to prevent the formation of non-connected portions, and it is possible to connect the substrates with high bonding strength.

A second embodiment of the present invention will be described below with reference to FIGS. 4 to 7. In this embodiment, the configurations of the first substrate 11 and the second substrate 15 are the same as those described above, and a plurality of first connection terminals 12 are formed on one side of the first substrate 11, and the second substrate 15 A plurality of second connection terminals 16 are formed on one side surface of the device in correspondence with the first connection terminals 12 .

When the first substrate 11 and the second substrate 15 are connected, they are bonded by thermocompression by sandwiching the first and second anisotropic conductive adhesives 22 and 23 as shown.

The process of forming the anisotropic conductive adhesive 22 and 23 on the first substrate 11 by pad printing will be described. FIG. 7 shows a schematic configuration of the pad printing device 17, and there are three tables 18a, 18b, 18c in the figure.
The first printing plates 19 are arranged in a row, and the table 18a at one end is provided with a first printing plate 19, and the table 18c at the other end is provided with a second printing plate 19.
A printing plate 20 is provided. The first substrate 11 is held on the central table 18b.

Further, a pad 21 is provided above these tables 18a, 18b, and 18c. This pad 21 is configured to move from the first printing plate 19 to the second printing plate 20 via above the first substrate 11.

The printed pattern 19a formed on the first printing plate 19 is strip-shaped, and the first anisotropic conductive adhesive 22 is formed with a uniform thickness over the entire length. In other words, the printed pattern 19a has a conventional configuration.

Further, the print pattern 20a formed on the second printing plate 20 is structured as shown in FIG. This printed pattern 20a is formed only on a portion of the first substrate 12 corresponding to the outside of the first connection terminal 12. In other words, the second anisotropic conductive adhesive 23 formed by this printed pattern 20a is the same as the first anisotropic conductive adhesive 23 formed by the printed pattern 20a.
This is only the portion corresponding to the end portion of No. 2, and the film thickness of this portion is increased.

The pad printing device 17 configured as described above first transfers the first anisotropic conductive adhesive 22 onto the first substrate 11 held on the table 18b at the center.

A paste-like first anisotropic conductive adhesive 22 is poured into the print pattern 19a of the first printing plate 19. and,
The pad 21 is lowered relative to the first printing plate 19, and the first anisotropic conductive adhesive 22 is transferred onto the pad 21.

This pad 21 is moved to the upper part of the first substrate 11',
It descends to a predetermined position and makes contact, thereby transferring the first anisotropic conductive adhesive 22 onto the first connection terminal 12 . This completes the first step.

The raised pad 21 moves onto the second printing plate 20 and descends. At this time, the paste-like second anisotropic conductive adhesive 23 has already been applied to the print pattern 20a of the second printing plate 20.
is being poured. Then, the second anisotropic conductive adhesive 23 is transferred to the pad 21 and rises, moves to the top of the first substrate 11, and descends to form a layer on the first anisotropic conductive adhesive 23. Print as shown. This completes the second step.

As shown in FIG. 4, the pad-printed first substrate 11 is bonded to the first anisotropic conductive adhesive 22 on the outside in the direction in which the first connection terminals 16 are arranged. Agent 2
3 is provided twice, and the film thickness is increased.

The second substrate 15 is bonded to the first substrate 11 provided with the first anisotropic conductive joint material 22 and the second anisotropic conductive adhesive 23 as described above. This second substrate 15 has a plurality of second
The connection terminal 16 corresponds to the plurality of first connection terminals 12 described above. In this state, the first substrate 11 and the second substrate 15 are heated and pressurized from the thickness direction. As a result, the respective anisotropic conductive adhesives 22 and 23 are melted and flowed to every corner to strengthen the bond. This completes the third step.

By performing such two printing steps, a film thickness that cannot normally be obtained can be obtained, and the film thickness of the first anisotropic conductive adhesive 22 corresponding to the outside of the connection terminal 12.16 is changed to the second film thickness.
It can be increased by anisotropic conductive adhesive 23. This results in
The mechanical strength of the bond between the first substrate 11 and the second substrate 15 at their ends can be increased, and the reliability of the connection between the connection terminals 12 and 16 can be increased.

In addition, if you try to increase the film thickness in one printing process,
The pad transferred the anisotropic conductive adhesive from the printing plate and could no longer be lifted. Therefore, by forming the portion with increased film thickness in two printing steps as described above, the necessary film thickness can be obtained by pad printing.

The anisotropic conductive adhesive connection structure shown in each of the embodiments described above can be particularly effective when applied to connections that require durability against deformation, such as connections between boards built into IC cards. Demonstrate.

[Effects of the Invention] (1) In an anisotropic conductive adhesive that connects a plurality of connection terminals arranged in one direction, the film thickness of the anisotropic conductive adhesive located outside in the arrangement direction of the connection terminals is reduced. Due to the increase,
Since a sufficient amount of anisotropic conductive adhesive is filled between the substrates in the areas where there are no connection terminals, it is possible to obtain a high bonding strength that could not be obtained with conventional structures.

(2) By transferring the first anisotropic conductive adhesive in the first step and transferring the second anisotropic conductive coupling agent in the second step, a film thickness that could not be obtained with conventional batt printing is achieved. It is also possible to reliably bond the substrates that correspond to the outside of the connection terminals.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention,
Figure 1 is a cross-sectional view showing the state in which an anisotropic conductive adhesive is provided on the first substrate, and Figure 2 is a cross-sectional view showing the state in which the first and second substrates are bonded with the anisotropic conductive adhesive in between. 3 is a sectional view of a printing plate used for pad printing of anisotropic conductive adhesive, FIGS. 4 to 7 are a second embodiment of the present invention, and FIG. FIG. 5 is a cross-sectional view showing a state in which an anisotropic conductive adhesive is provided on one substrate; FIG. Figure 6 shows the second example used for pad printing of anisotropic conductive adhesive.
A sectional view of the printing plate, FIG. 7 is a sectional view schematically showing a pad printing device used for pad printing, FIGS. 8 to 10 are conventional examples, and FIG. 8 is an anisotropic one for the first substrate. A cross-sectional view showing a state in which a conductive adhesive is provided, FIG. 9 is a cross-sectional view showing a state in which a first substrate and a second substrate are joined with an anisotropic conductive adhesive in between, and FIG. 10 is a pad printing device. FIG. DESCRIPTION OF SYMBOLS 11... First board, 12... First connection terminal, 13.
...Anisotropic conductive adhesive, 15...Second substrate, 16...
・Second connection terminal, 19...First printing plate, 20...Second printing plate, 1φ) Tsudo, 2...Second anisotropic conductive adhesive,...Second anisotropic conductivity glue.

Claims (2)

[Claims] (1) A first substrate, a plurality of first connection terminals made of a conductive pattern formed on the first substrate and arranged in one direction, and a layer formed in a band shape on top of these first connection terminals. an anisotropic conductive adhesive, a second substrate physically connected to the first substrate with the anisotropic conductive adhesive in between, and a conductive pattern formed on the second substrate. a plurality of second connection terminals arranged and electrically connected to the first connection terminal with the anisotropic conductive adhesive in between; An anisotropic conductive adhesive connection structure characterized in that the thickness of the adhesive is increased in a portion corresponding to the outer side in the arrangement direction of the first connection terminal and the second connection terminal. (2) A first connection terminal having a plurality of first connection terminals arranged in an array.
a first step of pad printing a strip-shaped first anisotropic conductive adhesive on the substrate along the arrangement direction of the first connection terminals;
a second step of pad printing a second anisotropic conductive adhesive overlapping a portion of the first anisotropic conductive adhesive corresponding to the outside in the arrangement direction of the first connection terminals; a third step of joining and thermocompression-bonding a second substrate on which a second connection terminal corresponding to the first connection terminal is formed, sandwiching the first anisotropic conductive adhesive and the second anisotropic conductive adhesive; An anisotropic conductive adhesive connection method characterized by comprising: