JP2505751Y2 - Bending resistant thermocompression bonding member - Google Patents

Description

[Detailed description of the device]

[0001]

The present invention relates to a liquid crystal display (LC).
D), electroluminescence (EL), light emitting diode (LED), electrochromic display (ECD), plasma display or other display device connection terminals and the circuit board on which the drive part is mounted, or between connection terminals of various electric circuit boards The present invention relates to a thermocompression-bonding connecting member used for connecting to.

[0002]

2. Description of the Related Art Conventionally, thermocompression-bonding connecting members are LCD, E
It is used for connecting a display device such as L, LED, ECD, and a plasma display to a rigid printed circuit board (PCB), or connecting between PCBs.

With the recent increase in size, color and density of displays, the number of circuits on various electric circuit boards using thermocompression bonding members has increased, and conversely the number of conductive lines of circuit patterns has been increased.
The width becomes more narrow, the strength is reduced, folding Re song is, breaking caused by pulling or the like is a big problem. In order to solve this, a method of improving the material of the conductive line to increase the strength or increasing the thickness of the base material of the thermocompression bonding member has been adopted. In addition, a reinforcing film is attached to the surface on which the conductive lines are formed or the surface opposite to the surface, on which this problem is addressed.

[0004]

However, since the conductive line is usually formed by a printing method such as screen printing, it is necessary to maintain the characteristics of the ink as a material, and therefore, there are many restrictions in improving the strength. It has become difficult to increase strength. Even if a conductive line having a certain degree of strength can be formed , the conductive line width becomes considerably finer in the recent miniaturized circuit patterns as described above, and the strength remains uncertain.

Furthermore, the base material of the thermocompression bonding member (hereinafter
The base material) itself, especially carrying the joint with the substrate to be connected.
That part to increase the thickness of the base material, which is limited because it causes a decrease in reliability due to reduction in the thermal conductivity, thermal strain and thermal deformation of the joint portion when the thermocompression bonding, it It is not preferable to have a thickness exceeding it . Figure 3 shows a conventional thermocompression bonding connection member, an end portion on one side of the substrate 1 in (a)
And the provided conductive lines 2 made of the intermediate section, both ends thereof is coated with anisotropic conductive adhesive film 3 to form the joint, the insulating intermediate portion resist layer 4, further thereon via an adhesive layer 7 covering paste in absolute <br/> edge cover film 5, the substrate (b)
And Installing Ri bonded via the adhesive layer 7 the reinforcing film 6 on the surface opposite to the surface provided with the first conductive lines.

However, these insulating cover films
Or reinforcing film has poor handleability in attaching process, if there is a certain thickness to the film, is stuck in terms of so-called "stiffness" film becomes thicker than necessary because of the difficulty of the film, further mass treatment is difficult Therefore, the productivity depends on the processing speed of this pasting process.
It is easy, also, or leave the air between the film and thermocompression bonding connection member involving air when affixed these. Further a structure with an insulating cover film to the conductive line forming surface, although it is possible to improve the insulation of the thermocompression bonding connection member, it was not effective in protecting the conductive line from breaking.

Accordingly, response by the method is not said to be a conductive line by Ri folding Re songs thermocompression bonding connection member is protected from disconnection, was also remains a problem on the process. Moreover, recent thermocompression bonding connection member 8 with the miniaturization of various electric products, often mounted by folding Re songs wanted compactly between for example LCD9 the circuit board 10 as shown in FIG. 4,
Therefore disconnection due Ri folding Re songs conductive lines many occurring this countermeasure is desired than before.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to solve the conventional issues mentioned above, the thermal conductivity of the time of thermocompression bonding, and without compromising the reliability after connection, conduction reliably circuit pattern protect your line, it intended to provide a thermocompression bonding connection member for connection between substrates under severe use conditions such as rising folding Re songs accurately and Usumi easily and quickly, flexing resistance of the first invention
The thermocompression bonding member is an insulating flexible base having a thickness of 5 to 50 μm.
On one side of the material, a plurality of conductive lines consisting of end and middle
With an anisotropic conductive adhesive film or an insulative adhesive film.
Have a joint with the connected circuit board that is covered with
On one side, at a position facing the middle part of the conductive line.
A flexible reinforcing film applied to a thickness of 5 to 50 μm
It is characterized by having. Bending-resistant thermocompression bonding of the second invention
The connecting member is made of an insulating flexible base material having a thickness of 5 to 50 μm.
A plurality of conductive lines consisting of an end and an intermediate part on the surface and the end.
Parts covered with anisotropic conductive adhesive film or insulating adhesive film
Of the conductive line.
It may be coated on the intermediate portion to a thickness of 5 to 50 μm.
Prevent the disconnection of the conductive line with the flexible reinforcing film.
It is characterized by having it on the surface opposite to the intended surface.

[0009] As the substrate to which the present invention is that apply the polyimide, polyester, polycarbonate, polyphenylene sulfide, ethylene - vinyl acetate copolymer, or one selected from synthetic resins such as polymethyl methacrylate
Et That Is, or include these laminates, but are not particularly limited as long as it uses a flexible substrate with an electrically insulating, dimensionally stable temperature variability, against an external force, the conductive Considering the adhesion to the line ink and the adhesive, the polyester film is preferable among them. The thickness of the base material is preferably 5 to 50 μm, preferably 10 to 30 μm in consideration of its flexibility and thermal conductivity.

The anisotropic conductive or insulating adhesive film adhesive in the bending-resistant thermocompression bonding member of the present invention may be either thermoplastic or thermosetting as long as it exhibits adhesiveness when heated . Thermoplastic materials have the advantage that they can be bonded by heating at relatively low temperature for a short time, but they are heat resistant.
On the other hand, thermosetting resins have a high adhesive strength and excellent heat resistance, but have a shorter pot life than thermoplastics, and the bonding conditions are high temperature and long time. Therefore, these may be appropriately selected according to the purpose of use.

As the thermoplastic adhesive, a polyamide-based adhesive,
Polyester, ionomer, ethylene - acetic acid bi two
Le copolymer (EVA), ethylene - acrylic acid copolymer (EAA), ethylene - methacrylic acid copolymer (EMA), ethylene - polyolefin such as ethyl acrylate copolymer (EEA), any of various synthetic rubber, more of these modified Examples of materials, composites, examples of thermosetting adhesives include epoxy resin-based, urethane-based, acrylic-based, silicone-based, chloroprene-based, nitrile-based synthetic rubbers, or a mixture thereof. curing agent in either case, the vulcanizing agent, control agent, deterioration inhibitor, heat the additive, the thermal conductivity enhancing agents, tackifiers, softening agents, coloring agents and the like may be appropriately added.

The conductive particles for imparting anisotropic conductivity include metal particles such as gold, silver, copper, nickel, palladium, stainless steel, brass and solder, ceramic particles such as tungsten carbide and silica carbide, Carbon particles, plastic particles whose surfaces are coated with metal, and the like can be used.

When this is dispersed in an insulating adhesive to form an anisotropic conductive adhesive film, if the blending amount of the conductive particles is too small, the conductive particles exist between the connection terminal to be connected and the conductive line. Lost, non-conducting or incomplete conducting,
If the amount is too large, the anisotropy is stochastically connected in the plane direction and the anisotropy is impaired. Therefore, the range may be 0.1 to 30 parts by volume with respect to 100 parts by volume of the adhesive component, but preferably 1 to 15 parts.
It is regarded as the capacity section. In addition, an anisotropic conductive adhesive film is formed by fixing conductive particles on the conductive line and then coating them with an insulating adhesive.
In that case, in order to obtain a stable connection, the number of particles is 20 or more per 1 mm ² of the conductive pattern area of the connection portion,
It is preferable that the number is 50 or more. The conductive line is formed on the base material by a known method using a known conductive ink.

Next, the bending-resistant thermocompression bonding member of the present invention
One embodiment will be described with reference to the drawings. 1 (a) is a plan view of the flex resistance thermocompression bonding connection member of the present invention, (b) is a sectional view enlarging only the thickness direction along the line X-X of (a), 1 is
The base material 2 is a conductive line that is formed on the base material 1 at the same pitch as the connection terminals of the substrate to be connected and has an end portion and an intermediate portion for connection . Both end portions of the conductive lines 2 are covered with different Hoshirubeden adhesive film 3, middle-section is covered with an insulating resist layer 4.
To face the middle portion of the back surface a and the conductive lines of the substrate 1 And
Located in the flexible reinforcing film (hereinafter, simply referred to as a reinforcing layer) that 1
1 is formed by coating.

The longitudinal sectional view enlarging only the thickness direction of the flex resistance thermocompression bonding connection member shown in FIG. 1 (c) shows a case where the conductive particles 12 are solid deposited on the conductive line 2, this time Can be connected to the connection terminals of the circuit board to be connected by covering at least both ends of the conductive line 2 with the insulating adhesive film 13. The middle portion of the conductive lines 2 are insulated register scan
Is covered with the base layer 4 and is on the back surface of the base material 1 and in the middle of the conductive line.
The reinforcing film 11 is formed by coating at a position facing the section.
ing. Although not shown, both ends of the base material and the middle
Conductive line consisting of, and its end is anisotropically conductively bonded
Cover with a film or an insulating adhesive film, and in the middle of the conductive line
After covering with an insulating resist layer, break the reinforcing film respectively.
It may be provided on the opposite side of the surface to be prevented.
it can.

The location of the reinforcing film provided on the substrate surface is as follows.
On the back surface of the base material 1 on which the conductive line 2 is provided, the conductive line
It suffices as long as it is a portion facing the middle portion of the above and does not hinder the connection, and when provided on both the front and back sides, the width and shape of the reinforcing film on the front surface and the back surface do not necessarily have to be the same. .

The material of the reinforcing film applied to the present invention is not particularly limited, but polyimide type, polyamide type, polyvinyl type, ionomer type, polyester type, polyurethane type, epoxy resin type, acrylic type,
Silicone-based, polyolefin-based, chloroprene-based, nitrile-based, etc. synthetic resins and synthetic rubbers, natural resins, natural rubbers, modified products thereof,
Alternatively, a mixture thereof may be used, and a curing agent,
Vulcanizing agents, control agents, deterioration preventing agents, heat the additive, a softening agent, a coloring agent and the like may be appropriately added.

[0018] In addition, as a coating method at the time of applying this
Or used in addition to a solvent or the like, if necessary, or to perform the curing by mixing two liquids, dimensional stability optimum condition corresponding to a coating fabric process, temperature variability, against an external force,
May be selected of materials in consideration of adhesion or the like to a substrate, also, may be formed as a laminate, the thickness of these reinforcement film, in consideration of the flexibility and strength 5-50
[mu] m, and it is preferably a 10 to 30 [mu] m. Reinforcement
If the thickness of the film is less than 5 μm, there is no disconnection prevention effect and it is thin.
In addition to being difficult to handle, it is easily wrinkled and bent.
Therefore, the conductive line is easy to peel and break. Over 50 μm
As a result, the rigidity of the bending-resistant thermocompression-bonding connecting member obtained becomes high.
Only made handling Inikuku in.

As a method for applying the reinforcing film, a printing method such as screen printing, gravure printing, etc. may be used, or roll coating, bar coating, knife coating, spray coating, spin coating, or You may use the dipping method,
Drying or curing reaction such as the further coating material optionally
To do . Coating formation of the reinforcing layer, after the thermocompression bonding connection member during production of the conductive lines of the printing process, or or placed before the news during product molding, can you to distribution or the like after the cutting process.

[0020]

[ Function ] The bending resistant thermocompression bonding member of the present invention has a reinforcing film.
Of the surface of the substrate provided with the conductive line having the end and the middle part
On the opposite surface, a position facing the middle part of the conductive line.
And the conductive layer on one of the substrates.
In order to prevent disconnection of the in,
A reinforcing film is provided on the back side to prevent disconnection. Guide
If electrical lines are provided on both sides of the substrate, the conductive lines on each side
Each of the cables is protected from disconnection by the back side reinforcement film.
It Specifically, as shown in FIG. 2A, the conductive line
When bent in the direction of the reinforcing film 11 from 2 (convex fold)
And the elastic force of the reinforcing film 11 prevents bending.
Elastic resistance occurs, and the bent part is bent with a small radius.
To prevent the conductive line 2 from cracking or breaking.
The electrical conductivity of the conductive line 2 is maintained without the need.

Conversely, as shown in FIG. 2 (b), fold in the opposite direction.
The elastic force of the reinforcing film 11 when bent ( mountain fold )
Causes elastic resistance to bending and further back
Due to the presence of the reinforcing film 11 on the conductive line 2, a large R is attached to the bent portion of the conductive line 2 , and the conductive line 2 is protected from disconnection.
Protected, the conductive line of the circuit pattern is surely protected against bending in either direction, and the connection between the circuit boards is accurately and surely made under severe usage conditions . This action is
The same applies when electric lines are provided on both sides of the substrate.
By the reinforcing film provided on the back side respectively.
Protected from disconnection .

[0022]

[Example] As a base material of a bending-resistant thermocompression bonding member, a thickness of 25
μm polyester film (Toray, Lumirror S-1
0) is used, and one side is made of silver carbon paste
Conductive line ink was used to form a large number of conductive lines composed of end portions and intermediate portions . Further, as the anisotropic conductive adhesive film in the connection portion, used was one in which SBR-based synthetic rubber was used as a main material, nickel particles were mixed as conductive particles, and titanium white was added to make it white. The middle part of the conductive line
It was covered with an insulating resist by a printing process.

The coating and formation of the reinforcing film in this embodiment are
After e final printing process of the insulating resist, opposing to an intermediate portion of the conductive line in the opposite side of the conductive line forming surface
15μ thickness as a reinforcing film by screen printing on the position
m so as to obtain a polyester resin. The bending-resistant thermocompression-bonding connection member (example) of the present invention thus obtained,
For the conventional thermocompression-bonding connection member having a conductive insulating film only on the conductive line forming surface (Comparative Example 1) and the thermocompression-bonding connection member having no insulating cover film and a reinforcing film (Comparative Example 2). Table 1 also shows the results of the resistance change rate test of the conductive line due to bending.

[0024]

[Table 1]

This bending test method is shown in FIG.
As shown in (b), the conductive line side is more conductive than the reinforcing film side.
Bend to 180 ° at the center of the line (valley fold)
Apply 50g / cm2 pressure for 1 minute, then opposite at the same position
180 ° bending (mountain fold) in this direction, this valley fold , mountain fold
Each of them was bent once, that is, 360 ° was bent once. In the thermocompression bonding members of Examples and Comparative Examples 1 and 2, the pitch of conductive lines was 0.3 mm, and the number of conductive lines was 240. From Table 1, flex resistance heat pressure of the present invention
The connecting / disconnecting member is the thermocompression-bonding connecting member of Comparative Example 1 and Comparative Example 2.
It is recognized that it is remarkably excellent.

[0026]

[Effects of the Invention] The flex-resistant thermocompression bonding member according to the present invention has a reinforcing film which is easily formed by coating, so that the conductive line is safely protected, and the connection is severely affected by impact, bending, etc. without impairing the reliability of the connection. Even under various conditions, there is no disconnection of the conductive line, and the connection terminals of the circuit board to be connected can be reliably connected and maintained. In addition, the reinforcement film is
It is provided at a position facing the middle part of the conductive line on the surface
Therefore, it does not soften or deform due to the heat during thermocompression bonding, and is resistant to bending.
Wrinkles do not enter the bendable thermo-compression bonding member, and wire breakage is prevented.
Therefore, the insulation of the conductive line is surely maintained.

[Brief description of drawings]

FIG. 1 is an example of a bending-resistant thermocompression bonding connection member of the present invention,
(A) is a plan view when the conductive particles are not fixed to the conductive line, (b) is a vertical sectional view taken along line XX of (a), and (c) is the conductive particles fixed to the conductive line. FIG.

2 (a) and 2 (b) are vertical cross-sectional views showing a bent state of the bending- resistant thermocompression bonding connection member of the present invention.

3A and 3B are vertical sectional views of a conventional thermocompression bonding member.

FIG. 4 is a vertical sectional view showing an example of a mounted state of a conventional thermocompression bonding member.

[Explanation of symbols]

1 substrate 2 conductive lines 3 anisotropic conductive adhesive film 4 insulating resist layer 5 insulating cover film 6 reinforcement film 7 adhesive layer 8 thermocompression connecting member 9 LCD 10 the circuit board 11 a reinforcing film 12 conductive particles 13 insulating adhesive film

Claims (2)

(57) [Scope of utility model registration request] 1. An insulating flexible base material having a thickness of 5 to 50 μm.
On one surface, a plurality of conductive lines consisting of end and middle parts
The ends are covered with an anisotropic conductive adhesive film or an insulating adhesive film.
And a joint portion with the connected circuit board that covers the other
5 to a position opposite to the intermediate portion of the conductive line on the surface.
Has a flexible reinforcing film applied to a thickness of 50 μm
A bending-resistant thermocompression-bonding connecting member characterized by the following. (2) Of an insulating flexible substrate having a thickness of 5 to 50 μm
On both sides, a plurality of conductive lines consisting of end and middle part and
Cover the ends with an anisotropic conductive adhesive film or an insulating adhesive film.
Conductive line having a joint with the connected circuit board
5 to 50 μm thick is applied on the intermediate part of
Flexible reinforcing membranes prevent the conductive lines from breaking.
The surface opposite to the surface to be tested.
Flexible thermo-compression bonding member.