JPS5823956B2 - Insatsu High Senban - Google Patents

Description

[Detailed description of the invention] The present invention relates to a conductor layer formed on a synthetic resin-based laminate.

This relates to a printed wiring board configured to connect electrodes of chip-shaped electrical components that do not have lead wires, lead wires of electrical components such as semiconductors and integrated circuits, and its purpose is to connect conductor layers and electrodes. This eliminates the inconvenience of silver migration to the conductor layer and solder containing silver when it is composed of a silver powder-resin system, and it also provides high-density electricity to both sides of the laminate regardless of the presence or absence of lead wires. The object of the present invention is to provide a printed wiring board on which components can be mounted.

In general, a printed wiring board is constructed by forming a conductive foil that constitutes a circuit pattern on a synthetic resin-based laminate, and the conductive foil of this printed wiring board has a chip-shaped electrical conductor that does not have a lead wire, such as a magnetic capacitor. When the electrodes of a component are attached, differential stress occurs between the electrical component and the synthetic resin laminate due to the large difference in thermal expansion coefficient between the two, and during use, this differential stress causes the electrode of the electrical component to There was an inconvenience that the connection with the conductor foil of the wiring board came loose.

Therefore, in conventional configurations, if heat is applied for a long time, such as when trying to mount electronic components on both sides, the above-mentioned differential stress will become large, and there is a risk that the board itself may warp or the electronic components may fall off. However, double-sided mounting was considered impossible.

In addition, when silver terminals are used as electrodes for chip-shaped electrical components that do not have lead wires, or when silver powder-resin-based conductive adhesives, silver-containing solder, etc. are used to bond electrical components and printed wiring boards, However, there was a problem with silver migration, which made it impossible to bond electrically good electrical components and printed wiring boards.

The present invention solves these drawbacks, and the following points are explained below.
The printed wiring board of the present invention will be explained with reference to drawings of embodiments.

In the figure, reference numeral 1 denotes a synthetic resin-based laminate, which is constructed by laminating a phenol resin on a paper substrate.

Reference numeral 2 denotes a through hole formed in the synthetic resin laminate 1, and an insulating layer 3 made of flexible epoxy resin is formed on the hole wall and both surfaces of the synthetic resin laminate 1.

This insulating layer 3 is made of, for example, epoxy resin No. 320 manufactured by Three Kamisaku Co., Ltd. to which 0.3 parts of dodecylamine is added, and this is applied to the hole walls and inner surfaces of the through holes 2 of the synthetic resin laminate 1. It is constructed by coating by a method such as a dipping method or a screen printing method, and then curing under atmospheric conditions at 120° C. for 30 minutes.

Reference numeral 4 denotes a conductive layer selectively formed on the hole wall of the through hole 2 of the synthetic resin laminated board 1 and the insulating layer 3 formed on both surfaces of the through hole 2, and A plating resist may be printed on areas other than arbitrary locations on both sides and formed by chemical plating or electroplating, or a notching resist may be used as a plating layer uniformly provided on the insulating layer 3. It is formed by selective etching.

Reference numeral 5 denotes a chip-shaped electrical component having no lead wire, and its electrode 6 is bonded to the conductor layer 4 on the upper surface of the laminated plate 1 using a conductive adhesive 7 to be mounted.

Reference numeral 8 designates a chip-shaped electrical component having no lead wire, which is attached in advance to the lower surface of the laminate 1 with an adhesive 9, and its electrode 10 is connected to the conductor layer 4 on the lower surface of the laminate 1 with solder 11. It is implemented by joining by

Reference numeral 12 designates an electrical component such as a semiconductor integrated circuit, whose lead wire 13 is inserted into a through hole 2 provided in the laminated board 1 and having a conductor layer 4 on only one side, and soldered 11 at 260° C. for 5 to 15 seconds.
It is implemented by being joined by

Here, a chinob-shaped electric component 8 without a lead wire is placed on the bottom surface of the laminate 1, and a knob-shaped electrical component 8 is placed on the top surface of the laminate 1, with its lead wire 13 protruding through the through hole 2 to the bottom surface. The electrical component 12 is mounted on the above-mentioned laminate board at the same time as the solder 11 is applied.

On the other hand, when the electrical components 8 and 12 are attached by soldering, the conductive adhesive 7 of the chip-shaped electrical component 5 without lead wires placed on the upper surface of the laminate 1 is heated, and thereby the electrical component 5 is mounted. It should be.

In a printed wiring board with such a configuration, the temperature is 40℃ and 90-95%.
Although a direct current of 100 V was applied under the high temperature and high humidity conditions of PH, migration of silver caused by silver conductors, silver-containing solder, silver electrodes, etc. did not occur for more than 1000 hours.

Further, a 100V 0.1 μF magnetic capacitor was mounted as an electronic component, and a thermal shock test was repeated 100 times at a temperature of -55 to 125° C., but there was no disconnection of the conductor layer 3 and no falling off of the electronic component.

As described above, according to the present invention, an insulating layer of flexible epoxy resin is formed on the hole wall of a through hole formed in a synthetic resin laminate and on both sides of the laminate, and a conductor layer is formed on the insulating layer. is formed, so the electrodes of electrical parts attached to it are chain terminals, the conductor layer is silver-resin, and the conductive adhesive for bonding is silver-resin. Even with solder, there is no silver migration, and the differential stress that occurs between a chip-shaped electrical component without lead wires and a synthetic resin laminate can be alleviated. This eliminates the inconvenience of disconnection from the conductor layer formed on the laminate.

Moreover, since this insulating layer is also formed in the through-hole portion of the synthetic resin laminated board, it is possible to prevent disconnection of the conductor layer provided in that portion.

Therefore, if electrodes of electrical components are placed on the conductive layer on the top side of the laminate via a conductive adhesive, the heat will harden the conductive adhesive during the process of soldering the bottom side.・Joining of terminals, etc. is completed simultaneously on the bottom side, and a printed wiring board with double-sided mounting can be easily obtained, and its industrial effects are outstanding.

[Brief explanation of the drawing]

The drawing is a sectional view showing an example of the configuration of a printed wiring board of the present invention. 1...Synthetic resin laminate, 2...Through hole, 3...Insulating layer, 4...Conductor layer, 5.
8.12... Electrical part, 6.10... Electrode, 7... Conductive adhesive, 9... Adhesive, 13... ··Lead.

Claims (1)

[Scope of Claims] 1. An insulating layer of flexible epoxy resin provided on the hole wall of a through hole in a synthetic resin laminate and on both sides of the laminate, and a surface of each insulating layer on both sides of the laminate, respectively. An electronic component with a lead wire is attached by soldering a patterned conductor layer provided and a lead wire that passes through a through hole and protrudes from the bottom surface of the laminate;
This soldering of electronic parts with lead wires is sometimes done with knob-shaped electrical parts in which the electrodes are directly soldered to the conductor layer on the bottom surface of the laminate, and the soldering process is sometimes carried out by soldering the conductor layer on the top surface of the laminate due to the heat of time. It has a chip-shaped electrical component on which electrodes are fixed by curing a conductive adhesive placed on top of the chip, and silver in the electrodes and conductive adhesive migrates through the insulating layer. A printed wiring board characterized in that the printed wiring board is configured such that the laminate is not deformed by the heat of soldering.