JPS61183880A - Thermo compression bonding connection between flexible substrate and other substrates or the like - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for electrically connecting a flexible substrate and another substrate or electronic component by thermocompression bonding.

[Conventional technology]

Flexible substrates, which are made up of multiple printed patterns on a base film, can be bent to match the internal shape of the device, and have a large degree of freedom in designing the device. It is beginning to be used in a wide range of fields such as various communication equipment and OA equipment.

In this flexible substrate, the base film may be a polyimide film, a polyester film,
It is known that because a heat-resistant polyester film or the like is used, the rate of dimensional change due to heating is particularly high, and the longer the film is, the greater the rate of dimensional change is.

Thermal factors that have a large effect on such dimensional changes of flexible boards include, for example, the method of thermocompression bonding between terminals, etc. provided at the connection part of a 7-lexiple board and terminals, etc. provided at the connection part of another board. This is thought to be due to heating during connection.

Therefore, at the time of design, it is necessary to make a correction that takes into account the dimensional change of the flexible substrate due to the thermocompression bonding (the correction value is different near the center of the base film and on both sides), and also to Since the connecting part cannot be made long, it is necessary to combine short dimensions to make a long length, and strict dimensional control has been required during processing, use, etc.

[Problem that the invention seeks to solve]

However, it is difficult to strictly control the dimensions of flexible circuit boards and requires advanced technology, so manufacturing costs are high, and even if dimension correction is considered during design, it is difficult to actually connect using thermocompression bonding. In this case, dimensional changes occur due to changes in the environment or conditions at that time, and as a result, there is a problem in that poor connection occurs when connecting with other substrates, electronic components, etc.

Furthermore, when connecting parts of a flexible board with short dimensions are combined to make the connection part of the flexible board long, there is also the problem that the number of man-hours increases.

The present invention has been made to solve these problems, and by reinforcing the connecting portions of flexible substrates and eliminating dimensional changes due to heating, it eliminates the need for dimensional correction when designing flexible substrates, and also A thermocompression bonding method for connecting flexible substrates to other substrates, etc., which prevents connection failures between flexible substrates and other substrates, etc., and which can connect a large number of terminals provided on a long connection part at once. The purpose is to achieve this goal.

[Means for solving problems]

In order to solve the above-mentioned problems and achieve the object, the present invention provides a reinforcing metal on the surface opposite to the terminal formation surface or the conductor formation surface for component mounting in the connection part of the flexible board. A thermocompression bonding means is brought into contact with the reinforcing metal, and the terminals, etc. of the connecting portion are connected to the terminals, etc. of the connecting portion of another board, etc. by the thermocompression bonding method.

[Function] According to the above-mentioned means, the connecting portion of the flexible substrate is not reinforced by the reinforcing metal against dimensional changes due to heating, and the terminals of the connecting portion can be connected to other substrates by thermocompression bonding. No dimensional change occurs even when heated by thermocompression bonding means when connecting with terminals, etc. of the section. Therefore, connection failures, etc. are prevented, and a large number of terminals, etc. can be connected all at once.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a thermocompression bonding method for connecting a flexible substrate to another substrate, etc. according to the present invention, and FIG. 2 is a partial perspective view of the flexible substrate used in this embodiment.

In Fig. 1, 1 is a flexible substrate, for example, the thickness is 2
Base film 2 made of 5 μm polyimide film (I)
A printed pattern 3 is provided on one or both sides of the base film 2, and a connection portion 2 is provided at the end of the base film 2 in order to connect to another board (hereinafter referred to as the other board) to be described later.
A terminal 3 extending from the printed pattern 3 on one side of a.
A'iz is formed, and a reinforcing metal 4 is provided on the surface opposite to the terminal forming surface of the connecting portion 2a, and further both surfaces of the base film 2 excluding the terminal forming surface of the connecting portion 2a are provided. It has a structure covered with a cover lay film 5. still,
Reference numeral 6 indicates a printed pattern 3f on both sides, and a through hole for electrical conduction.

In this embodiment, the connecting portion 2a is formed to be long, but the dimensions were not corrected at the time of design, and the terminal 3a is oriented perpendicular to the longitudinal direction of the connecting portion 2a, as shown in FIG. They are formed in large numbers parallel to each other at regular intervals.

Furthermore, in this embodiment, the shape of the reinforcing metal 4 provided on the surface of the connecting portion 2a opposite to the terminal forming surface is a shape in which two parallel bands are connected at both ends. 2a
As long as dimensional changes can be prevented, the shape and size do not need to be critical; for example, they may be rectangular or mesh-like. As the reinforcing metal 4, in addition to copper foil, any metal commonly used for flexible circuit boards can be used, and it is also possible to use plated metal. .

Now, returning to the explanation of FIG. Terminals 8a extending from the printed pattern 8 on the mating board γ are formed on 7a so as to correspond to the terminals 3a of the flexible board 1.

9 is a thermocompression bonding means.

Therefore, in order to connect the terminals 8a and 8b of the flexible substrate 1 and the mating substrate 7, the flexible substrate 1
After dehydration treatment by heating at a temperature of 110° C. for 30 minutes, for example, pre-soldering (not shown) is applied to each terminal 3a of the connecting portion 7a and other necessary parts at a temperature of 220° C. for 3 seconds, and Electronic components are connected to connection parts for component mounting (not shown) by thermocompression bonding, for example, at a temperature of 170 to 220° C. for 10 minutes.

Thereafter, as shown in FIG. 1, the connecting portion 2a of the flexible substrate 1 and the connecting portion 7a of the mating substrate 7 are overlapped, the terminals 3a and 8a are aligned, and heat is applied from the outside of the coverlay film 5. While bringing the front end surface of the pressure bonding means 9 into contact with the reinforcing metal 4 and applying pressure with the thermocompression bonding means 9,
For example, heating is performed at a temperature of 280° C. for 3 minutes to connect the terminals 3a and 8a.

The procedure of the thermocompression bonding method of this embodiment has been explained above, but in this embodiment, the connecting portion 2a of the flexible substrate 1 is
Therefore, when dehydrating, pre-soldering, and connecting electronic components, the connecting portion 2a will not undergo dimensional changes even when heated at high temperatures as described above, and after that, the terminals 3a and 8a will not change in size. When connecting the connecting parts 2, the thermocompression bonding means 9 is brought into contact with the reinforcing metal 4 and heated.
It is possible to perform a highly reliable terminal-to-terminal connection without any dimensional change in a.

As a result of experiments, multiple connections were made using thermocompression bonding in the same manner as in the above embodiment using a flexible board with 300 terminals on the connection part and a mating board with similar terminals.
When reinforcing metal was not provided at the connection part of the flexible board, 22Oram tended to change dimensions by 0.6 m, resulting in poor connection, but when reinforcing metal was provided at the connection part, no dimensional change occurred. The results showed that no connection failures or short circuits occurred.

In the above-mentioned embodiments, the connection part of the flexible board that is connected to the connection part of the other board is explained, but the present invention is not limited to this, and the present invention is not limited to this, but can also be applied to the formation of a conductor of a connection part having a conductor on which an electronic component is mounted. By providing a reinforcing metal on the opposite side, it is possible to eliminate the occurrence of dimensional changes as in the above-mentioned embodiment, and it is possible to make a highly reliable connection with the conductor of the electronic component. .

〔Effect of the invention〕

As explained above, the present invention provides a reinforcing metal on the surface opposite to the terminal forming surface or the conductor forming surface of the connecting portion of the flexible substrate, and brings the thermocompression bonding means into contact with the reinforcing metal. A method of connecting terminals of a connecting part or conductors for mounting components to terminals of other boards or electronic components by thermocompression bonding, in which the reinforcing metal prevents dimensional changes in the connecting part of a flexible board due to heating. Because it is reinforced against heat, heat is not applied during dehydration processing, preliminary soldering, etc.
However, the dimensions of the connection part do not change even when the connection is made, so it is easy to align with terminals on other boards and electronic components. Since no change occurs, it is possible to achieve the effect that connections can be made without causing connection failures or short circuits.

In addition, as mentioned above, there is no need to make corrections at the time of design because there is no dimensional change in the connection part, and the reinforcing metal acts as a cushion against the pressure applied by the thermocompression bonding means, which improves heat conduction. This helps ensure a secure and reliable connection.

Furthermore, since the dimensions of the connecting portion of the present invention do not change and are stable, it is possible to provide a long connecting portion and connect a large number of terminals at once.
Since there is no need to form a long connection part by combining short dimensions as in the conventional method, there is also the effect that the number of man-hours can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a thermocompression bonding method for connecting a flexible substrate and another substrate according to the present invention, and FIG. 2 is a partial perspective view of a flexible substrate used in this embodiment.

Claims (1)

[Scope of Claims] 1. A reinforcing metal is provided on the terminal forming surface of the connecting portion of the flexible substrate or the surface opposite to the conductor forming surface for component mounting in order to eliminate dimensional changes in the connecting portion due to heating, and The terminal or conductor of the connection part is overlapped with the terminal of another board or the conductor of the electronic component, and a thermocompression bonding means is brought into contact with the reinforcing metal, and heat is applied while applying pressure with the thermocompression bonding means to bond the terminals. Alternatively, a thermocompression bonding method for connecting a flexible board and another board, etc., characterized by connecting conductors.