JPS60178690A - Circuit board - 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 Field of Industrial Application The present invention applies to a large number of conductive patterns arranged on a substrate.
The present invention relates to a wiring board for electrically connecting other wiring boards or integrated circuits (ICs) each having a corresponding conductive π (zR pattern).

Backpacking technology and its problems Conventionally, for a large number of conductive/l turns provided on a wiring board of an electronic device, such as a flexible board or a rigid board, it has been arranged similarly to correspond to these conductive Pttj''/4' turns. A large number of conductors such as 11 turns and leads of components such as ICs are electrically connected (for example, on a flexible board).This electrical connection is Connection by soldering is mainly used, but this soldering process involves laminating or pressing a resist for the solder in advance except for the parts to be soldered, and then applying solder to the parts to be soldered using roll soldering or the like.
This requires a complicated process of soldering and electrical connection using a soldering iron, which is disadvantageous in that it is difficult to manufacture.

OBJECTS OF THE INVENTION In view of the above, an object of the present invention is to provide a wiring board that can be easily electrically connected to other wiring boards or ICs.

Summary of the invention The invention is to apply an insulating adhesive that melts and flows when heated, in which metal particles made of a metal that melts when heated under pressure are dispersed, and an insulating film is formed on the surface of the entire surface or a predetermined portion of a wiring board. Therefore, according to the present invention, electrical and mechanical connections with other wiring boards, ICs, etc. can be made easily and reliably.

EXAMPLE 1 Hereinafter, an embodiment of the wiring board of the present invention will be described with reference to FIGS. 1 to 3.

In Figure 1, 1. , (1) is a glass epoxy fiber impregnated with epoxy! l! A glass epoxy substrate is shown, and a 181 rm thick Cu foil adhered to the glass epoxy substrate (1) is selectively etched to form a 03 pitch (width 0.15++ IW 1. spacing 0.15).
A wiring board is constructed by forming a plurality of strip-shaped conductive patterns (2) arranged in parallel with each other. On this conductive pattern (2), hot-melt type insulation 1. An adhesive layer (5) is formed by applying a dispersion of low melting point solder metal particles (4) with an oxide film formed on the surface to a resistant adhesive (3).
form. This insulating adhesive (3) had the following composition.
00 parts by weight of low melting point solder metal particles (4) were mixed.

These metal particles (4) are pulverized using a pulverizer in the air to an average particle size of 30 μm, and the surface of the low melting point solder metal particles (4) is coated with an insulating layer. An oxide film is formed. This Pb-8n-C
The melting point of the d alloy is 143°C. In this way, coat the adhesive paint with low melting point solder metal particles (4) dispersed in the insulating adhesive (3) on the conductive/4' turn (2) so that the thickness after drying is 40 mm. Apply the adhesive layer (5
) and a release paper (6) is applied onto this adhesive layer (5).

In this example, as shown in Fig. 2, a flexible substrate (7) made of a sheet-like preimide substrate with a thickness of 50 trIn is used.
When electrically connecting the conductive pattern (8) of another wiring board having a conductive pattern (8) made of Cu foil having the same dimensions and shape as the conductive mother turn (2) on the conductive pattern (2), Peel off the release paper (6) and check the conductivity of the wiring board/4'
A predetermined portion of the substrates (1) and (7) is overlapped so that the turns (2) and (8) face each other and overlap each other, and the overlapping portion is heated at 180°C as shown by arrows a and b. So 4
Heat and pressurize for 20 seconds at 0 kV'crl. In this way, as shown in FIG.
) exhibits fluidity υ1 property when heated, especially the conductive patterns (2) and (7) which are subjected to pressure because they substantially protrude from the mutually facing surfaces of both substrates (1) and (7).
8) Much of the insulating adhesive (3) interposed between them is extruded to the side, and these conductors (fW) 4 turns (2) and (8)
In between, the low melting point semi-ITI metal particles (4) are melted and crushed by heating and pressing. In this case, the oxide film formed on the surface of the low melting point solder metal particles (4) is torn by pressure, and the conductive patterns (2) and (8) are soldered and electrically connected. The wiring board to which the conductive patterns (2) and (8) are connected in this way has a conduction resistance at this connection part, that is, a conductive pattern (2) and a conductive pattern (8).
The actual measured value of the conduction resistance between 2) and the corresponding conductive pattern (8) was 0.008Ω, and the insulation resistance between adjacent connection parts was 1.5×10 2 Ω. In this case, since an insulating oxide film is formed on the surface of the low melting point solder metal particles (4), even if the particles that are not melted are in contact with each other, the 1F air resistance is extremely large and the particles are almost insulated. It was recognized. Then, this wiring board was subjected to forced aging treatment for one week at 80C1 relative humidity of 95 degrees, and the resistance value was then measured, and the conduction resistance was 0.1Ω.

Insulation resistance is 8. At OX 10'Ω, almost no change was observed in the characteristics.

In this way, the conduction resistance at the connection part is made sufficiently small,
As long as the insulation resistance between the connecting parts can be made sufficiently large, the insulating adhesive (3), which has been made highly movable by heating and pressurizing as described above, has a conductive 'lj /4' turn ( The insulating adhesive (3) is extruded from between 2) and (8) to the outside (lIll), and both are well fused by the solder metal particles (4) whose oxide film has been broken, and the insulating adhesive (3) is extruded to the outside of the connection. wraps the metal particles (4) well, and the metal particles (
4) has an insulating oxide film on its surface, and a large amount of this adhesive (3) is present between adjacent connection parts, thereby firmly adhering both substrates (1) and (7). This seems to be due to this.

Next, with reference to FIGS. 4 and 5, the present invention is applied to flexibly form a liquid crystal motherboard (9) having a large number of terminals (9a) (9a)... and an ICQI for driving it. A specific example of connection via the wiring board (11) will be explained.

In FIGS. 4 and 5, parts corresponding to those in FIGS. 1 to 3 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

As this flexible wiring board (II)) N25μ
Insulating flexible substrate (li imide film)
st), a 167 m thick Cu foil was selectively etched to form a plurality of strip-shaped conductive patterns with a pitch of 0.4 wm (2
) was completely formed, and an adhesive layer (5) having the following composition was applied over the entire surface of the conductive turn (2) so that the thickness after drying was 30 μm. The composition of this adhesive is as follows.

For the insulating adhesive of this composition, solder metal particles (4), which are made by pulverizing glass-ceramic bonding soil El ((Cerasolzana 123, manufactured by Asahi Kasei Corporation) using a pulverizer in the air to an average particle size of 20 gm), are uniformly added. 120 parts by weight were mixed so as to be dispersed.In this case, since the solder for adhesion to glass ceramics was pulverized in the air, an insulating oxide film was formed on the surface of the solder metal particles (4). The melting point of solder for ceramic bonding is 145°C.

This flexible wiring board (one end of the mark is a liquid crystal) or flannel (
9) 04 rigid pitch pattern transparent electrode (ITO) (
9a) (9a)... are stacked so that the conductive patterns (2) face each other and overlap each other via the adhesive layer (5), and the other end of this flexible wiring board (1υ) is placed on a glass epoxy board (12). (12a) (12a) =
- and putter 7 (2) (2) -... face each other and align the wheels so that they are 1f apart, and the overlapping parts are set at 150℃, 50ky/cf, and 15 seconds as shown in Fig. 5. The adhesive was bonded by applying heat and pressure as shown in the figure. As a result, a good electrical connection was obtained as described above. In an unusual case, there are many conductive patterns (2) (2)... and (9m) (9a
)... electrical connection and numerous conductive patterns (2)
There is an advantage that the electrical connection between (2) and (12a) and (12a) is simple, and it can also be mechanically connected using the adhesive (3). Also, in this case, the adhesive (3) of the adhesive layer (5) deposited on the conductive Fn pattern (2) (2) is an insulator, and the surface of the solder metal particles (4) is insulated. Since a conductive oxide film is formed, it has the advantage of insulating the conductive patterns (2) (2), etc. in the unconnected parts and also serving as a time-storage.

Next, we will discuss the case where ICQt) is connected to a glass epoxy substrate (12 glue) in a fixed position.In this case, a 911 m thick Cu foil is etched on the glass epoxy base &f12 in advance to form a predetermined guide box pattern. Then, as shown in Fig. 4, the connection terminal (
i2b)02b)... An adhesive layer (5) having the following composition is applied in a substantially rectangular shape on the part. The composition of this insulating adhesive was selected as follows.

Low melting point solder (Pb-8
An n-Cd alloy (melting point: 143° C.) was ground in air using a grinder to an average particle size of 10 jrrIL, and 150% of low melting point solder metal particles (4) having an insulating oxide film on the surface were ground. The genitals were mixed and dispersed.

This board (L5 IC connection terminal (12b) (12b)
・Place the flat grooved cage IC (10 terminals on top of each other with the adhesive layer (5) interposed in between, and place 180
As shown in FIG. 5, the overlapping portions were heat-pressed and bonded under the conditions of 9/d at 40° C. for 10 seconds. Good electrical and mechanical connections were also obtained in this case.

In the above embodiment, it was described that the adhesive layer (5) was applied directly to the wiring board, but this adhesive JW! Of course, it is also possible to apply (5) on a release paper and apply the adhesive layer on the release paper to the entire surface or a predetermined portion of the wiring board. Furthermore, the present invention is not limited to the above-described embodiments, and it goes without saying that other configurations may be adopted without departing from the gist of the present invention.

Effects of the Invention According to the present invention, there is an advantage that electrical connection with other wiring boards, FiIC, etc. can be made simple, and mechanical connection can also be made.

[Brief explanation of the drawing]

FIG. FIG. 5 is an exploded perspective view showing the connection shape of FIG. 4. (1) is an insulating substrate, (2) is a conductive mother turn, (3) is an insulating adhesive, (4) is a metal particle whose surface has an insulating oxide film, (5) is an adhesive layer, and (6) is an insulating substrate. ) is release paper. Figure 1

Claims (1)

[Claims] The wiring board is characterized by being coated with an insulating adhesive that melts and flows when heated, in which metallic particles made of metal particles are dispersed and melted when heated, and an insulating film is formed on the surface of the wiring board. wiring board.