JPH104248A - Board connection structure - Google Patents

Abstract

(57) [Problem] To provide a substrate connection structure capable of sufficiently increasing connection strength when connecting substrates. SOLUTION: One of four circuit patterns 13 and 43 formed on the synthetic resin films 11 and 41 is drawn out to one end of the synthetic resin films 11 and 41 to form connection portions 12 and 42, and two flexible substrates 10 and 42 are provided. 40 is provided. A notch 23 is provided in the connection portion 12 of one flexible substrate 10. Connection part 12 of both flexible substrates 10 and 40,
By bonding the circuit patterns 13 and 43 of each other via an anisotropic conductive adhesive 80, each of the circuit patterns 13 and 43 is
43 are electrically connected to each other. The notch 2 is formed from above the connecting portion 12 of the flexible substrate 10 having the notch 23.
An insulating synthetic resin 85 for reinforcement is applied so as to fill in No. 3 and cured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate connection structure suitable for connecting substrates.

[0002]

2. Description of the Related Art Heretofore, there has been a case where an electronic component is connected by soldering to a predetermined position of a circuit pattern on a flexible substrate having a circuit pattern formed on a synthetic resin film. In such a case, a polyimide film having high heat resistance that can withstand the heat of soldering has been used as the synthetic resin film.

In order to connect this type of flexible board to another printed circuit board installed at a remote place, a strip-shaped flat cable is extended from a portion where electronic components are soldered, and the flat board is connected to the flat board. There is a structure in which the tip of the cable is attached to another printed wiring board or the like.

[0004]

However, the polyimide film used as the synthetic resin film is expensive, and it is not economical to construct the entire flexible substrate including the flat cable using this material.

On the other hand, polyethylene terephthalate (P) is used as an inexpensive synthetic resin film constituting a flexible substrate.
ET) film, but the PET film had low heat resistance, and it was not possible to solder electronic components to this flexible substrate.

In order to solve the above-mentioned drawbacks, a portion for soldering electronic components in the flexible substrate is constituted by a flexible substrate made of a polyimide film, and a portion constituting a flat cable is constituted by a PET film. What is necessary is just to comprise a flexible board and to connect both.

That is, as shown in FIG. 7, a flexible substrate 95 provided with four circuit patterns 93 on the lower surface of a polyimide film 91 and a flexible substrate 105 provided with four circuit patterns 103 on the upper surface of a PET film 101.
And the ends of the flexible substrate 95 and the ends of the flexible substrate 105 are joined to each other via a hot melt type anisotropic conductive adhesive 111, and heated and pressurized from above and below to electrically connect both ends. Just connect them. Incidentally, both 97 and 107 shown in the figure are insulating resists.

However, the two flexible substrates 9
When the connection of 5,105 is made only with the anisotropic conductive adhesive 111, there is a problem that the mechanical connection strength is weak.
Therefore, a separate reinforcing synthetic resin 12 is provided between the tip side a of the flexible substrate 95 and the upper surface of the flexible substrate 105.
A method of applying 1 to reinforce the fixation between the two is conceivable, but the connection strength is not always sufficient because only the tip side a is fixed.

[0009] The present invention has been made in view of the above points, and an object of the present invention is to provide a substrate connection structure capable of sufficiently increasing the connection strength when connecting substrates.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention comprises two substrates having predetermined portions of a plurality of circuit patterns formed on the surface as connecting portions, and connecting the two substrates to each other. In a board connection structure in which the circuit patterns provided on the both boards are electrically connected to each other by bonding the parts together via a conductive adhesive, at least one of the two boards is used. A notch or a hole is provided in the connecting portion of the above, and a reinforcing insulating synthetic resin is applied from above the connecting portion of the substrate provided with the notch or the hole so as to fill the notch or the hole.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view of an essential part showing a method for manufacturing a substrate connection structure according to one embodiment of the present invention. As shown in the figure, in the present embodiment, the connection portions 12 provided at the end portions of the two flexible substrates 10 and 40,
42 are adhered to each other via a conductive adhesive 80, and an insulating synthetic resin 85 is applied to the upper surface of the adhered portion.
Hereinafter, each component will be described.

FIG. 2 is a plan view showing the entire structure of the flexible substrate 10. As shown in FIG. As shown in FIG. 1, the flexible substrate 10 is configured by providing four circuit patterns 13 on the upper surface of a substantially circular polyimide synthetic resin film 11 and covering the circuit patterns 13 with an insulating resist 15.

Here, the four circuit patterns 13 are formed by etching a copper foil adhered on the synthetic resin film 11 and further plating the entire upper surface thereof by soldering. A land pattern 17 is formed at the center, and the other end is drawn out to the outer periphery of the synthetic resin film 11 to form a connection portion 12.

The connecting portion 12 is formed by projecting a circular synthetic resin film 11 from the outer periphery thereof in a strip shape, and leaving the four circuit patterns 13 at the leading end thereof to form the synthetic resin film 11 therearound in a comb-like shape. And a notch 23 is provided.

The insulating resist 15 is a synthetic resin such as an epoxy-based or polyester-based resin, and is screen-printed on the synthetic resin film 11 excluding the connection portions 12 and the four land patterns 17.

In this embodiment, the thickness of the synthetic resin film 11 is 0.025 mm, the thickness of the copper foil forming the circuit pattern 13 is 35 μm, and the thickness of the insulating resist 15 is about 15 μm.

The synthetic resin film 11 constituting the flexible substrate 10 is made of polyimide having high heat resistance, and the circuit pattern 13 is made of copper foil or solder plating. For soldering.

FIG. 3 is a plan view of a main part showing the flexible substrate 40. As shown in FIG. As shown in the figure, the flexible substrate 40 is configured by providing four circuit patterns 43 in parallel on the upper surface of a belt-shaped PET synthetic resin film 41 and covering the circuit patterns 43 with an insulating resist 45.

The four circuit patterns 43 are formed by screen-printing a silver paste on the synthetic resin film 41. One end of the circuit pattern 43 is drawn out to one end of the synthetic resin film 41 to form a connection portion 42. ing.

The insulating resist 45 is a synthetic resin such as an epoxy or polyester resin, and is screen-printed on the synthetic resin film 41 excluding the connection portion 42.

The other end of the flexible substrate 40 is
It has the same structure as the connection part 42, and a metal terminal plate is attached in some cases. That is, the flexible substrate 40 is a so-called flat cable.

In this embodiment, the thickness of the synthetic resin film 41 is 0.075 mm, the thickness of the circuit pattern 43 is 10 μm, and the thickness of the insulating resist 45 is about 15 μm.

In order to connect the flexible substrates 10 and 40, as shown in FIG. 1, a hot melt type anisotropic conductive adhesive is first placed on each circuit pattern 43 of the connecting portion 42 of the flexible substrate 40. Print 80.

Then, the connection portion 12 of the flexible substrate 10 turned upside down is placed on the connection portion 42. At this time, the circuit patterns 13 and 43 are accurately opposed.

When the connection portions 12 and 42 are heated and pressed in the thickness direction by a hot press (not shown), conduction in the anisotropic conductive adhesive 80 occurs only in the thickness direction, and the opposing circuit patterns 13 and 43 are formed. At the same time, the connection between the two connecting portions 12 and 42 is mechanically fixed.

Next, an insulating synthetic resin 85 made of an ultraviolet-curable acrylic resin is applied on the connecting portion 12. At this time, the notch 23 provided in the connection portion 12 is filled with the insulating synthetic resin 85. The insulating synthetic resin 85 is cured by irradiating ultraviolet rays. Note that another adhesive such as an epoxy resin may be used as the insulating synthetic resin 85.

FIGS. 4A and 4B are views showing a connection structure of the flexible substrates 10 and 40 formed as described above. FIG. 4A is a longitudinal sectional view, and FIG. 4B is a transverse sectional view.

According to this connection structure as shown in FIG.
By filling the inside of the notch 23 provided on one of the flexible substrates 10 with the insulating synthetic resin 85, the fixing between the two connection portions 12 and 42 by the insulating synthetic resin 85 is performed in each notch 23 portion. The mechanical connection strength increases.

Instead of the notch 23 shown in the above embodiment, a hole 23-2 may be provided in the connection portion 19-2 as in a flexible substrate 10-2 shown in FIG. With this configuration, the connection work is facilitated because the distal ends of the connection portions 19-2 do not fall apart. Further, the strength against the force in the pulling direction to the flexible substrate 10-2 increases.

The flexible substrate 10-3 shown in FIG.
The projection 25 may be protruded from the side of the notch 23-3 of the connection portion 19-3 as shown in FIG. Even with such a configuration, the strength against the force in the pulling-out direction to the flexible substrate 10-3 increases.

Needless to say, the shapes of the notches and holes are not limited to the above embodiments.

In each of the above embodiments, the example in which the notch 23 and the like are provided on the flexible substrate 10 side has been described, but the notch 23 and the like may be provided on the flexible substrate 40 side. 40 may be provided.

In the above embodiment, a polyimide film having high heat resistance is used as the flexible substrate 10 on which the electronic components are soldered, and an inexpensive PET film is used as the other flexible substrate 40. It is needless to say that the material and the use are not limited, and the point is that the connection portion between two flexible substrates can be used for the connection between flexible substrates of other materials.

In the above embodiment, the flexible substrate is used as the substrate, but a hard substrate may be used.

In the above-described embodiment, the connecting portion is provided at the end of the substrate. However, the connecting portion does not need to be at the end of the substrate, and may be provided inside the substrate.

[0036]

As described above in detail, according to the present invention, there is an excellent effect that the connection strength when connecting the substrates can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing a method for manufacturing a substrate connection structure according to an embodiment of the present invention.

FIG. 2 is a plan view showing the entire configuration of the flexible substrate 10;

FIG. 3 is a main part plan view showing a flexible substrate 40;

4A and 4B are diagrams showing a connection structure of the flexible substrates 10 and 40, wherein FIG. 4A is a longitudinal sectional view and FIG. 4B is a transverse sectional view.

FIG. 5 shows a flexible substrate 10- used in another embodiment.
It is a principal part perspective view which shows the 2nd connection part 19-2.

FIG. 6 shows a flexible substrate 10- used in another embodiment.
It is a principal part perspective view which shows the connection part 19-3 of No. 3.

FIG. 7 is a diagram showing a conventional example.

[Explanation of symbols]

 10, 40 Flexible substrate 11, 41 Synthetic resin film 12, 42 Connection part 13, 43 Circuit pattern 23 Notch 80 Conductive adhesive 85 Insulating synthetic resin 23-2 Hole 23-3 Notch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // H01B 7/00 306 H01B 7/00 306

Claims (2)

[Claims] 1. A semiconductor device comprising: two substrates having predetermined portions of a plurality of circuit patterns formed on a surface as connecting portions, wherein the connecting portions of the two substrates are bonded to each other via a conductive adhesive. In a board connection structure in which circuit patterns provided on both boards are electrically connected to each other, a notch or a hole is provided in a connection portion of at least one of the boards, and the notch is further provided. A substrate connection structure, wherein a reinforcing insulating synthetic resin is applied from above a connection portion of a substrate provided with holes so as to fill the notches or holes. 2. The board connection according to claim 1, wherein at least one of the two boards is a flexible board formed by forming a plurality of circuit patterns on a synthetic resin film. Construction.