JPH07226569A - Circuit board, electrode connection body, and method for manufacturing the same - Google Patents

Abstract

(57) [Abstract] [Purpose] An inexpensive and highly reliable circuit board that does not need to be coated with a new liquid adhesive at the time of connection, an electrode connection body using the circuit board, and a manufacturing method thereof. I will provide a. [Structure] Electrode 11 and insulating substrate 9 are made of thermoplastic adhesive 1
A circuit board pre-bonded with 0 is used. At the time of connection, the electrode 11 of the circuit board and the electrode 13 of the printed board 12 are pressed and heated by the pressing tool 14 in a state of being matched with each other. The heated and fluidized thermoplastic adhesive 10 fills the space between the substrate 12 and the insulating substrate 9 to bond them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board, a connecting body using the circuit board, and a connecting method with an electronic component such as an LCD, a magnetic head, and a printed board.

[0002]

2. Description of the Related Art Due to the recent downsizing trend of electronic parts, fine connection technology with a pitch of several hundred μm to several tens of μm is required, and from the viewpoint of global environment protection, solder (lead contained therein) is used. There is a need to develop connection technology that does not use the.

As a connection technique which does not use solder, a photocurable or thermosetting adhesive resin is interposed between the electrodes to be joined and pressure is applied between the electrodes, and the adhesive resin is applied with light or heat. There is a connection technique for curing and maintaining the electrical connection between the electrodes by utilizing the contraction force at the time of curing.

An example of a conventional connection method that does not use solder will be described with reference to FIG. In FIG. 1, 1 is an electronic component, 2 is an electrode formed on the electronic component 1, 3 is a photocurable or thermosetting insulating resin, 4 is a pressure tool, 5 is a film lead, and 7 is a dispenser. .

Since the insulating resin 3 is irradiated with ultraviolet rays (UV) from the electronic component 1 side, the electronic component 1 is, for example, L
Like a CD panel, it transmits UV light, and the electrode 2 is also generally a UV light transmissive ITO electrode. 5
Is generally a film lead of a TAB package.

Now, in the connection step, first, as shown in FIG. 2A, a photocurable insulating resin 3 is applied onto the electrode 2 of the electronic component 1. At this time, the resin 3 is uniformly applied onto the electrodes 2 of the electronic component 1 by the dispenser 7.

Next, as shown in FIG. 2B, the electronic component 1
After the upper electrode 2 and the film lead 5 are aligned with each other, the electrode 2 and the film lead 5 are pressed by the pressing tool 4.

Next, the insulating resin 3 is cured by irradiating ultraviolet rays from the surface opposite to the electrode 2 on the electronic component 1 while the film lead 5 is pressed. After the curing, if the pressure is removed as shown in FIG. 2 (c), the electrode 2 and the film lead 5 on the electronic component 1 are mechanically held and electrical conduction is obtained.

In the above connection method, the insulating resin 3 is a photo-curable resin, but a thermosetting resin may be used. In any case, the insulating resin is applied using a dispenser.

The smaller the size or the formation pitch of the electrodes 2, the smaller the amount of insulating resin applied, but the smaller the amount applied, the more difficult it becomes to control the amount applied. If the coating amount is too large, the protruding resin adheres to the pressure tool, which causes inconvenience.

Further, since the resin has a high viscosity, it is difficult to remove air bubbles mixed therein, which causes a decrease in reliability due to the inclusion of air bubbles in the connection portion. Therefore, the equipment for resin coating becomes complicated and expensive.

Further, when the coating amount is reduced, the amount of resin discarded for maintenance of equipment is larger than the amount of resin actually used for connection, which causes a cost increase in terms of materials. .

[0013]

In order to solve the above-mentioned problems, the present invention provides a flexible printed circuit board in which an insulating substrate and conductor wiring are fixed by a thermoplastic adhesive. The step of matching the electrodes that are part of the conductor wiring with the electrodes of the electronic component,
Adhesion between the electrodes of the flexible printed circuit board is brought into close contact with the surface of the electronic component by applying pressure and heating in a matched state, and cooling of the flexible printed circuit board is brought into close contact with the adhesive of the flexible printed circuit board. The flexible printed circuit board and the electronic component are fixed by the adhesive, and the electrode of the flexible printed circuit board, which is a part of the conductor wiring, and the electrode of the electronic component are bonded by the adhesive. An electrode connecting body is used which is in contact with each other due to the fixing of the agent.

[0014]

Using the circuit board according to the present invention, in which the conductor wiring is fixed to the insulating substrate with the adhesive, the circuit board and the electronic component are fixed with the adhesive, and a part of the conductor wiring is provided. According to the electrode connector and the method of manufacturing the same, the electrode of the circuit board and the electrode of the electronic component are in contact with each other by fixing the adhesive.

(1) Since the adhesive that fixes the base film and the electrodes of the flexible printed circuit board is used for connection, it is not necessary to apply an insulating resin in the process, and therefore, the equipment such as a dispenser and the insulating property are not required. No resin is required, and it is very inexpensive from the viewpoint of equipment and materials.

(2) Since no liquid resin is used, air bubbles do not occur at the time of connection, and even if air bubbles are included, they can be found at the stage of the flexible printed circuit board, so that a defect occurs. The cost can be reduced significantly.

(3) Since air bubbles do not enter the connecting portion, the reliability of the connecting portion is improved. (4) Since the liquid resin is not used, the resin does not adhere to the tool pressing surface due to the resin squeeze out, so that the yield is improved.

Due to the reasons (5) and (2), the reliability of the connection portion is improved and it is possible to cope with a fine pitch.

[0019]

EXAMPLE One example of the present invention will be described with reference to FIG. FIG. 1A shows a sectional view of the flexible printed board. 9 is a base film, 10 is a thermoplastic adhesive, 11 is an electrode of a flexible printed circuit board, 1
2 is a printed circuit board, 13 is an electrode of the printed circuit board, and 14 is a pressure tool.

The base film 9 is generally made of polyimide, polyester or the like. The electrode 11 is generally a metal mainly composed of copper, and the surface thereof is plated with nickel or the like depending on the application.

The adhesive 10 is a thermoplastic adhesive such as vinyl acetate resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, polyamide or the like.

The flexible printed circuit board shown in FIG. 1 is manufactured as follows. The base film 9 and a flat metal foil for conductor wiring are fixed with a thermoplastic adhesive 10, and then the metal foil is etched to form a conductor wiring pattern. After that, the cover film 16 is further fixed to the conductor wiring with an adhesive. However, a cover film is not applied to a part of the conductor wiring pattern as illustrated. The conductor wiring not covered with the cover film is used as an electrode by plating the surface according to the application.

In this manner, first, a flexible printed circuit board having a structure as shown in FIG. 1 (a), having a five-layer structure, in which the base film 9 and the cover film 16 are fixed with the thermoplastic adhesive 10 around the electrode 11, is formed. prepare. However, an electrode portion not covered with the cover film 16 is formed on a part of this substrate.

Generally, the thickness of each of the base film 9 and the cover film 16 is 25 μm, and the thickness of the electrode 11 is 10 to 50 μm.
m, the thermoplastic adhesive 10 is about 10 to 200 μm. In addition, the surface of the normal electrode 11 is plated with a metal such as Au, Sn, or solder according to the application. The pitch of the electrodes 11 is about 50 to 500 μm.

The volume of the thermoplastic adhesive 10a sandwiched between the electrode 11 and the base film 9 is larger than the volume of the void 17 formed between the adjacent electrodes 11. Further, usually, the surface of the electrode 11 projects from the surface of the thermoplastic adhesive 10 by 5 μm or more.

Next, as shown in FIG. 1B, the electrode 11 of the exposed portion which is not covered with the cover film 16 is exposed.
And the electrode 13 of the printed circuit board 12 are aligned.
At this time, the base film 9 of the flexible printed circuit board
When a transparent material is used for the thermoplastic adhesive 10 and
Flexible printed circuit board electrode 11 and printed circuit board 1
Alignment with the second electrode 13 is possible from the base film 9 side.

If an opaque material is used as the above-mentioned material, in order to align the electrode 11 and the electrode 13, it is necessary to obtain the positional information of the electrodes 11 and 13 by using cameras of separate systems. However, in the present embodiment, since only one camera for alignment is required, the apparatus is very inexpensive.

Next, as shown in FIG. 1 (c), pressure is applied by the pressure tool 14 so that the electrode 1 of the flexible printed circuit board is pressed.
1 and the electrode 13 of the printed board 12 are brought into contact with each other to obtain electrical contact.

When performing this pressurization, the electrode 11 and the electrode 1
It is preferable that the pressure contact with 3 is performed uniformly.

To that end, the pressure tool 14 as shown.
When directly contacting the base film 9 with each other, it is preferable to sufficiently control the parallelism between the pressure tool and the printed board 12 and the parallelism of the pressure surface of the pressure tool. If a cushioning material (not shown) such as a fluorine film is inserted between the flexible printed board and the base film 9, the required accuracy such as parallelism can be relaxed.

Further, at the time of pressurization, the pressurizing tool 14 is in a heated state, and therefore, heating is performed simultaneously with pressurization.

By the heated pressure tool, the thermoplastic adhesive 10a sandwiched between the electrode 11 and the base film 9 and the adhesive 10b between the electrodes 11 are heated and softened.

The softened adhesive flows under pressure, but since the amount of the adhesive 10a under the electrodes 11 is larger than the volume of the voids between the electrodes 11 as described above, this softened adhesive is used. The voids 17 are filled with the softened thermoplastic adhesive 10 by the flow of, and the adhesive filling the voids contacts the surface of the substrate 12. The void 1
The air of 7 is discharged outside as the thermoplastic adhesive is filled.

Thereafter, the pressurized pressure tool is cooled, and the temperature of the thermoplastic adhesive 10 is lowered to cure it. At this time, since the thermoplastic adhesive 10 is a curing shrinkage type whose volume shrinks during curing, this curing shrinkage force acts as a force for pressing the electrode 11 through the base film 9 of the flexible printed circuit board, resulting in a flexible print. The electrical connection between the electrode 11 on the substrate and the electrode 13 on the printed circuit board 12 is further ensured.

Finally, the pressure is released to complete the connection.
Incidentally, FIG. 1E shows a sectional view of FIG.

In the invention of the present application, the already cured adhesive is heated and appropriately flowed to bond the substrates to each other, whereas in the conventional connection method, a liquid adhesive resin for connection is applied. Therefore, it is not only difficult to prevent air bubbles from being mixed into the liquid resin in the coating step, but it also causes an increase in the cost of the device for that purpose, or when air bubbles remain, the connection of the substrate There is a problem that the reliability of the connection deteriorates due to the bubbles mixed in the portion.

When a defective product is generated due to the presence of such bubbles, it is necessary to either discard it as a defective product or perform repair work, which has been a factor of cost increase.

On the other hand, in the present invention, even if a bubble is generated, it can be found before the lead stage shown in FIG. 1, that is, before an expensive semiconductor device is connected. It is advantageous from the viewpoint of cost reduction and the like since no work is required.

[0039]

According to the present invention, a circuit board in which a conductor wiring is fixed to an insulating substrate with an adhesive and an electronic component are fixed with the adhesive, and the circuit board is a part of the conductor wiring. According to the electrode connector and the method of manufacturing the same, the electrode and the electrode of the electronic component are in contact with each other due to the adhesion of the adhesive.

(1) Since the adhesive that fixes the base film of the flexible printed circuit board and the electrode is used for connection, it is not necessary to apply an insulating resin in the process, and therefore the equipment such as a dispenser and the insulating property are not required. No resin is required, and it is very inexpensive from the viewpoint of equipment and materials.

(2) Since the liquid resin is not used, the resin does not adhere to the tool pressing surface due to the resin squeezing out, so that the pressing tool can be easily maintained.

(3) Since liquid resin is not used, air bubbles are not mixed in the resin at the connecting portion, and reliability is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the steps of an embodiment of a method for manufacturing an electrode assembly according to the present invention.

FIG. 2 is a sectional view showing a conventional method for manufacturing an electrode assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic component 2 Electrode of electronic component 3 Insulating resin 4 Pressure tool 5 Film lead 7 Dispenser 9 Base film 10 Thermoplastic adhesive 11 Electrode 12 Printed circuit board 13 Electrode 14 Pressure tool 16 Cover film 17 Void

Claims (9)

[Claims] 1. A circuit board having conductor wiring formed on an insulating substrate, wherein a thermoplastic adhesive layer is formed on the insulating substrate, and the surface of the conductor wiring is the adhesive layer. A circuit board, wherein the circuit board is fixed to the insulating substrate by the adhesive layer in a state of being exposed from the surface of the. 2. A state in which the conductor wiring is in non-contact with the insulating substrate at least at the location where the electrical connection is made, and the surface of the conductor wiring for the electrical connection projects from the adhesive layer. And the amount of adhesive between the conductor wiring and the insulating substrate is larger than the volume of the gap between the protruding conductor wirings. 1. The circuit board according to 1. 3. The circuit board according to claim 1, wherein the conductor wiring is covered with an insulating material on the surface of the conductor wiring other than the location where the electrical connection is made. 4. The circuit board according to claim 1, wherein the thermoplastic adhesive and the insulating substrate are transparent at least at a location where the conductor wiring is electrically connected. 5. The circuit board according to any one of claims 1 to 4, wherein the thermoplastic adhesive is a cure shrink type in which the volume shrinks in a cured state as compared with a softened state. 6. The circuit board according to claim 1, wherein the circuit board is a flexible printed board. 7. The circuit board according to claim 1, wherein the conductor wiring is fixed to the insulating substrate with an adhesive, and the electronic component is fixed with the adhesive. An electrode connector, wherein an electrode of a circuit board, which is a part, and an electrode of an electronic component are in contact with each other by being fixed by an adhesive agent of the circuit board. 8. A step of matching an electrode of an electronic component with a connecting portion of the conductor wiring formed on the circuit board according to claim 1, wherein the conductor wiring is fixed to the insulating substrate with an adhesive. By pressing and heating the circuit board in a matched state, the electronic component and the circuit board are fixed by an adhesive between the electrodes of the circuit board, and the electrode of the circuit board and the electrode of the electronic component are fixed. A method for manufacturing an electrode-connecting body, comprising electrically connecting with and by contacting. 9. The connecting portion of the conductor wiring formed on the circuit board according to claim 4, wherein the conductor wiring is fixed to the insulating substrate with an adhesive, and the electrode of the electronic component from the side of the insulating substrate. A step of confirming and matching the positions of both, pressurizing and heating the circuit board in the matched state, by the adhesive between the electrodes of the circuit board, to fix the electronic component and the circuit board, A method of manufacturing an electrode connection body, comprising electrically connecting an electrode of the circuit board and an electrode of the electronic component by contact.