JPH054889B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] This invention relates to a method for manufacturing printed wiring board materials.

[Background technology]

Printed wiring board materials are generally produced by the following method. In other words, an inner layer circuit board in which an inner layer conductor circuit is formed on metal foil such as copper foil stretched on one or both sides of a base material, and a metal foil-clad laminate or metal foil as an outer layer material are placed between these. To,
It is laminated via a prepreg obtained by semi-curing resin impregnated into a paper or glass cloth base material. When there are a plurality of inner layer circuit boards, they are stacked with the prepreg interposed between them. A common method was to sandwich the molded object obtained by this lamination between upper and lower pressing plates, and then heat and pressurize it. Recently, an autoclave vacuum forming method has been used because it allows for the production of higher quality printed wiring board materials. In this manufacturing method, multiple stacked objects to be molded are covered with bag film, sealed and placed in an autoclave, and while the inside of the bag film is depressurized, gas pressure is applied from the outside of the bag film, and the inside of the autoclave is A printed wiring board material is obtained by heating the gas using convection electric heat heated by a heater. In this manner, since this manufacturing method performs molding while degassing, a printed wiring board material with fewer voids (internal air bubbles) can be obtained compared to other conventional manufacturing methods.

However, this manufacturing method also had the following problems. In other words, the object to be formed is heated by convection heat transfer of gas around the object, and the temperature at the outer periphery of the object increases first, and then the temperature at the center gradually increases. I was getting used to it. For this reason, the semi-cured resin on the outer periphery of the molded object is first melted, and then the central part is gradually melted. However, by the time the center reaches a molten state, the outer periphery has already hardened, and the gas in the center cannot escape, creating voids in the resulting printed wiring board material and deteriorating its quality. It was hot. As described above, printed wiring board materials with voids have problems such as cracking during high-temperature processing such as soldering, and significantly reducing the reliability of through holes.

[Purpose of the invention]

In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a printed wiring board material that can obtain a printed wiring board material of high quality and stable quality.

[Disclosure of the invention]

In order to achieve such an object, the present invention places a molded product sandwiched between two molds in a bag, and reduces the pressure inside the bag so that the molded product is exposed to the reduced pressure. When obtaining a printed wiring board material by heating and pressure forming, the two molds also serve as high-frequency electrodes, and by applying a high-frequency voltage between the molds, the object to be molded is heated by high-frequency dielectric. The gist of this paper is a method for manufacturing a printed wiring board material characterized by the following.

The present invention will be explained in detail below with reference to the drawings showing one embodiment thereof.

As shown in FIG. 1, a plurality of molded objects 1 are stacked and sandwiched between two molds, an upper mold 21 and a lower mold 22. A flat spacer 6 is inserted between each of the molded objects 1, 1. Upper mold 21, lower mold 2
Holes 31 for positioning and through which pins 5, which serve as part of the electric circuit, are passed are formed at the four corners of 2, respectively. The contact portions of the holes 31 with the pins 5 are fitted with insulators 32 in each of the upper mold 21 and the lower mold 22, except for one place, so that the pins 5 and these molds are insulated. .

The method for manufacturing the printed wiring board material according to the present invention is carried out as follows. First, the lower mold 22 is placed on the base plate 23, the four pins 5 are set up on the lower mold 22, the objects 1 and the spacers 6 are alternately stacked on the lower mold 22, and finally the upper mold 21 is placed on the lower mold 22. let
At this time, the upper mold 21 and the lower mold 22 must be assembled so that the holes 31 in which the insulator 32 is not fitted are not connected by the pins 5. That is, two of the four pins 5 are each electrically connected to either the upper mold 21 or the lower mold 22. This upper mold 21 and lower mold 22
High-frequency electrode plugs 7, 7 connected to the high-frequency power source 13 are inserted and connected to the pins electrically connected to the high-frequency power source 13 from the lower surface 25 of the plate 23 through holes provided in the base plate 23. That is, the upper mold 21 and the lower mold 22 also serve as high frequency electrodes. In FIG. 3, 12 is a suction port connected to a vacuum pump. Since the structure of the mold is like this, the cable connecting the high frequency power supply 13 and the molds 21 and 22 can be taken out from the bottom of the lower mold 22, and unnecessary protrusions can be avoided when covering and sealing with baggage film, which will be described later. The advantage is that the pressure is applied evenly when pressurized.

In this way, the molded object 1 sandwiched between the molds 21 and 22...
As shown in FIG. 4, cover with baggage film 10. A breather 11 is inserted between the bag film 10 and the molded object 1 to improve ventilation between the two. The end of the bag film 10 is brought into close contact with the base plate 23 with a sealant tape 15, and the molded object 1 sandwiched between the molds 21 and 22 is sealed by the bag film 10 and the base plate 23. This base plate 23 is placed on the trolley 18 as shown in FIG.
be brought inside. The autoclave 19 includes a heater 42 that heats the inside of the autoclave, a cooler 41 that cools the molded product after hot molding, and the autoclave 1
9, a fan 43 for stirring the atmosphere, and a vacuum pump 4
A suction pipe 44 connected to 6 is provided.

Next, the suction pipe 44 of the vacuum pump 46 and the high-frequency electrode plugs 7, 7 are connected, and the autoclave 19 is sealed. And Batsugu Film 10
The vacuum pump 46 is depressurized to expose the molded product to a reduced pressure atmosphere, the high frequency power source 13 is turned on, the molded product is heated by high frequency dielectric heating, and the autoclave 19 is heated by the heater 42.
The inside of the bag film 10 is heated, and the bag film 10 is heated and pressurized from the outside to obtain a printed wiring board material. The object to be molded 1 is uniformly heated over the entire surface by high-frequency dielectric heating, and unlike the conventional method, the outer peripheral portion is not cured first and voids are not accumulated in the central portion.

The method for manufacturing the printed wiring board material according to the present invention is not limited to the above embodiments. The outside of the bag film is usually molded in a heated and pressurized atmosphere, but in some cases heating may not be necessary. All you have to do is heat it as needed. Heating and pressurizing may be performed by another method without using an autoclave.

It is preferable that the spacer be made of a material with a higher dielectric constant toward the center of the step. In this way, the high frequency dielectric effect can be enhanced.

〔Effect of the invention〕

The manufacturing method of the printed wiring board material of this invention involves placing a molded object sandwiched between two molds into a bag, reducing the pressure inside the bag, and heating and pressurizing the molded object while exposing it to the reduced pressure. When molding to obtain a printed wiring board material, the two molds also serve as high-frequency electrodes, and by applying a high-frequency voltage between the molds, the object to be molded is heated by high-frequency dielectric. , the object to be molded is heated evenly, and voids are no longer generated. Therefore, it becomes possible to obtain printed wiring board materials of high quality and stable quality.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view showing the main parts of the apparatus used for manufacturing the printed wiring board material according to the present invention, Fig. 2 is an assembled perspective view of the mold part, and Fig. 3 is an exploded perspective view thereof. , FIG. 4 is a side cross-sectional view illustrating the state in which the autoclave is sealed with a bag film over it, and FIG. 5 is a structural explanatory diagram of the autoclave. 1...Object to be molded, 10...Bag film, 2
1...upper mold, 22...lower mold.

Claims (1)

[Scope of Claims] 1. A molded object sandwiched between two molds is placed in a bag, and the inside of the bag is depressurized, and the molded object is subjected to heat and pressure molding while being exposed to the reduced pressure and printed. When obtaining a wiring board material, the two molds also serve as high-frequency electrodes, and the object to be molded is heated by high-frequency dielectric heating by applying a high-frequency voltage between the molds. Manufacturing method for plate materials. 2. The method for manufacturing a printed wiring board material according to claim 1, wherein the outside of the bag is in a heated atmosphere. 3. Claim 1, in which a plurality of objects to be formed are stacked via spacers and simultaneously heated and press-molded.
A method for producing a printed wiring board material according to item 1 or 2. 4. The method for manufacturing a printed wiring board material according to claim 3, wherein spacers made of a material having a higher dielectric constant are used toward the center stage.