JPS63146494A - Manufacture of metal core metal foil cladded laminated 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 relates to a method for manufacturing a metal-core metal foil-clad laminate used as a through-hole printed wiring board for high-density packaging for electronic equipment.

Conventional Techniques With the miniaturization and high quality of electronic devices, high-density mounting is required for printed wiring on boards.1 For example, after processing a through-hole printed wiring board with a solder leveler, chips are mounted and reflowed at high temperature. Implementation method.

Furthermore, after reflow, it can be mounted discretely.

Methods that involve numerous heat treatments, such as soldering methods, are now being applied to replace traditional single discrete packaging. Furthermore, for high-density mounting of ICs, LSIs, etc.
It was also necessary to consider heat dissipation. In response to this situation, copper-clad laminates, which serve as substrates for printed wiring boards, are
(1) Even when subjected to heat treatment in the printed wiring board manufacturing process (for example, solder repeller treatment) and heat treatment in the mounting process (for example, reflow treatment), "warpage" and "dimensional change" are small.

(2) Through-holes, which are the basis for high-density mounting, can be easily and highly reliable.

(3) Furthermore, it also has heat dissipation properties.

etc. are strongly requested.

To deal with this, efforts have been made to improve the base materials of conventional paper and glass cloth base materials and thermosetting resin copper-clad laminates, or to add inorganic fillers to thermosetting resins. , the above-mentioned "warp"
It was not possible to satisfy "dimensional change" and "heat dissipation".

As another improvement method, (n) a metal lover copper-clad laminate has been proposed in which a metal plate is inserted between a glass cloth layer impregnated with a thermosetting resin. However, in copper-clad laminates made using this method, the metal plate is inserted all over the inner layer, so when through-hole holes required for high-density wiring or holes for inserting discrete components are provided, the metal plate is inserted into the wall of the hole. There is a problem that the layer is exposed and electrical conduction occurs, and as a result, through-holes cannot be formed as it is, and the only possible use is as a single-sided printed wiring board.

(I [I) In order to make the metal-core metal foil-clad laminate of the previous (II) into a through-hole printed wiring board, for example, a thermosetting resin may be used on the hole wall of the through-hole one component insertion hole. A method of providing an insulating coating may also be considered, but this step involves applying resin to the small holes, a complicated method that is not suitable for mass production, and is extremely costly. In addition, due to variations in the amount of resin deposited on the hole wall, the hole diameter is not uniform, making it difficult to mount a single component, and there is also a problem with the adhesion between the hole wall and the resin, resulting in a lack of reliability after heat treatment. There was a drawback.

Problems to be Solved by the Invention The present invention has been made in view of the above points, and it is possible to provide through-holes and component mounting holes necessary for high-density mounting without fear of internal conduction, and it is possible to provide a printed wiring board. It is an object of the present invention to provide a metal-core metal foil-clad laminate that exhibits little "warpage" and "dimensional change" even during heat treatment during component mounting, and maintains heat dissipation properties.

Means for Solving the Problems The present invention has been made to achieve the above objects.
A large number of openings are provided in the metal plate. After inserting a prepreg piece cut from a prepreg obtained by impregnating and drying a thermosetting resin into a sheet-like base material into the opening, a sheet-like material such as paper, glass cloth, glass nonwoven fabric, etc. is placed on both surfaces of this metal plate. It is characterized in that a prepreg obtained by impregnating and drying a thermosetting resin on a base material is layered, a metal foil is further layered on the outside of this prepreg, and this is integrated by heating and pressing.

Operation The present invention has the above-mentioned characteristics, and due to the effect of the metal plate serving as the core material, there is less warpage after heat treatment in the printed wiring process and the chip mounting process of this printed wiring board, and dimensional changes are also reduced. .

Furthermore, through-hole holes and discrete component mounting holes can be provided in the openings of the metal plate, ie, the portions into which the prepreg pieces are inserted, and there is no fear of conduction in the inner layer.

Moreover, due to the presence of the insulating layer formed by curing the prepreg, sufficient strength can be maintained and dimensional changes during heating can be suppressed as much as possible, and the above-mentioned objective can be achieved.

Examples In carrying out the present invention, metal plates that can be used include:
Commercially available aluminum plates, iron plates, or aluminum plates or iron plates that have been subjected to anodic oxidation, acid or alkali surface activation treatment, particle treatment, etc. are suitable. Also, the opening of the metal plate has a different shape.

The size, shape and size of the remaining metal parts can be selected as appropriate depending on the type of printed wiring board, but in order to be able to provide more through holes and component holes and to easily insert prepreg pieces, As shown in FIG. 3, it is desirable that the length al of the opening 2 of the metal plate 1 is made larger than the length (b) of the metal part between adjacent openings. Also,
To enable a universal printed wiring design, the openings in the metal plate should have the same shape and be spaced at regular intervals.

Further, the metal plate opening may be provided by a punching method using a metal mold. At this time.

As shown in FIG. 1, a prepreg 3 is stacked on a metal plate 1 and inserted into a punching die 4.4'. And metal plate 1
At the same time as forming the opening 2 in the.

A prepreg piece 3' punched out in the same shape as the opening 2,
It is best to insert it into opening 2). That is.

This method requires that a prepreg piece 3' that perfectly matches the shape of the opening 2 of the metal plate 1 is inserted into the opening 2 of the metal plate 1 during press forming in the post-process, and that positional shift is prevented. It is preferable that it can be mass-produced, and the prepreg and metal plate are simultaneously punched out using a punching die, and at the same time an opening is formed in the lower metal plate, the upper prepreg piece is inserted into the opening. . This is a so-called bush pack in which a piece of prepreg is held in an opening of a metal plate. Thereafter, metal foil 5 is layered on both sides with prepreg 3 interposed between them, and the metal foil 5 is heated and pressurized to integrate (C1゜The prepreg to be placed on both surfaces of the prepreg piece and the metal plate may be paper, glass cloth, glass, etc.). A base material such as non-woven fabric is impregnated with varnish such as phenol resin, epoxy resin, polyester resin, etc., dried, and adjusted to prevent significant resin flow during the heating and pressurizing process.Also, metal foil Commercially available copper or nickel chromium foils can be used, or if particularly high adhesiveness is required, adhesive-coated metal foils may be used.

One or more sheets of prepreg adjusted in this way.

The conditions for placing metal foil on both sides of the metal plate and then inserting it into a press and forming it under heat and pressure are conditions for manufacturing general phenol, epoxy, and polyester laminates, such as a temperature of 160℃. ~170°C1 pressure 50~11
0k) One condition of heating and pressurizing at 7 m for 20 to 60 minutes can be applied.

Example 1 Bisphenol A type epoxy resin (product name Ko Pico) 1
001, manufactured by Yuka Shell Co., Ltd.) 100 parts by weight Novolac resin (Percam TD-2093, manufactured by Dainippon Ink Co., Ltd.) 24 parts by weight, dissolving solvent 2-ethyl-4-methylimidazole 0.2
A varnish for impregnation was prepared by adding acetone as a solvent to parts by weight.

A glass cloth base material (trade name #7628, manufactured by Asahi Schneebel) was impregnated with the varnish and dried to produce an epoxy resin-impregnated glass cloth prepreg with a resin amount of 400 parts by weight. Roughening treatment (particle treatment 5mmμ), thickness 0.4mm, size 50
2 plies of prepreg are stacked on top of a 0x5009 aluminum plate, inserted into a punching die and punched out, an opening is provided in the aluminum plate, and at the same time, a prepreg piece is punched into the opening in the same shape as the gate. inserted.

Two plies of the above prepreg were stacked on each side of the aluminum plate, and 35 μ thick copper foil was placed on both sides, inserted into a mirror plate, and pressed at a temperature of 170°C and a pressure of 80°C.
After heating at kp/m for 60 minutes, it was cooled to obtain an aluminum lover copper-clad laminate with a thickness of 1.2 mm.

This copper-clad laminate has a pattern design so that the through holes are placed in the openings of the aluminum plate.

A through-hole printed wiring board as shown in FIG. 2 could be easily manufactured by a conventional method (6 is a through-hole hole). Also, warping during the manufacturing process and heat treatment (chip mounting process) of printed wiring boards.

The dimensional changes were as shown in Table 1.

Comparative Example 1 Two prepregs used in Example 1 were stacked on each side of the 0.4X thick aluminum plate without openings used in Example 1, and 35μ thick copper foil was further placed on both sides, Insert it into a mirror plate and mold it under the same molding conditions as Example 1, 1.2
A copper-clad laminate containing 8 aluminum and having a thickness of X was obtained.

This copper-clad laminate cannot be subjected to a conventional through-hole process, and the hole walls must be subjected to special insulation treatment after the holes are formed, and the diameter of the holes for mounting components changes, which poses practical problems.

Comparative Example 2 Six prepregs of Example 1 were stacked, and 35
A μ-thick copper foil was placed, inserted into a mirror plate, and molded under the same molding conditions as in Example 1 to obtain a -1.2X thick copper-clad laminate.

Table 1 shows the warping and dimensional changes when this copper-clad laminate was applied to a through-hole printed wiring board production process using a conventional method and during heat treatment.

Table 1 Note 1) % after full surface etching of copper clad laminate 300x300% M ax lifting after treatment at 150°C for 30 minutes (
n=3).

2) Komei etched the copper clad laminate 300x300%,
M a after solder through hole processing and solder leveler processing
x uplift (n=3).

3) After using a 300x300 copper-clad laminate as a through-hole wiring board, chip mounting was performed, and M ax was raised after reflow treatment (n = 3).

4) Dimension change size aooxaoo nine to 180°C30
After processing.

It should be noted that if the step of stacking the metal plate and the prepreg and punching them is performed as shown in FIGS. 4 to 6 below, the prepreg can be inserted into the opening of the metal plate even better.

That is, the metal plate 1 is placed on top of the prepreg 3, and this is inserted into the punching die 4.4'.
A punch 7 is built in to sandwich and hold the prepreg 3 and metal plate 3 to be punched from opposite sides of the punching. This punch 7 is.

It is elastically supported by urethane rubber 8, and during punching, the urethane rubber 8 shrinks and presses against the punch 7.
The prepreg 3 and the metal plate 1 are held between the punching die 4 and the punching die 4, and when the punching is finished, the punched prepreg piece 3' and the metal plate piece 1' are held in the recess of the punching die 4' as shown in FIG. Get it in there.

On the other hand, a metal plate 1 and a prepreg 3 with an opening formed therein.
The punching die 4 is also held by a stripper plate 9 which is resiliently supported by contracting urethane rubber 8'.
It's stuck in.

Thereafter, by lowering the punch 7 and raising the stripper plate 9, the punched prepreg piece 3' is pushed back and inserted into the opening formed in the metal plate 1 (FIG. 6).

In the above process, the part to be punched out is held between the top and bottom, so the punching process is performed without meandering or moving. Therefore, the dimensional accuracy of the part to be punched and cut out is good, and brittle materials and materials with strong tensile strength (especially in the case of glass cloth base prepreg)
It is also possible to punch out multiple sheets of prepreg.

Effects of the Invention As shown in Table 1, the metal foil-clad laminate according to the present invention has the following advantages: (1) There is little warping even during heat treatment encountered in the printing wiring and mounting process, and there is little dimensional change, and it is easy to process. (It was excellent in mass production and did not cause any problems.)

(2) Due to the effect of the metal core, not only the above advantages but also improved strength and excellent heat dissipation properties are achieved.

(3) There is sufficient space in the areas where through-holes and component holes are provided, and there are almost no restrictions on pattern design. This is a method that can be completely removed and is suitable for mass production.

(4) A prepreg piece obtained by impregnating and drying the base material of the sheet board with a thermosetting resin is also inserted into the opening of the metal plate, and since this resin has been cured, it has excellent strength and through-hole reliability. It is something that

[Brief Description of the Drawings] Fig. 1 is a cross-sectional explanatory diagram showing an example of the manufacturing process of a metal-core metal foil-clad laminate according to the present invention, and Fig. 2 is a g-foil-clad laminate with a metal core according to the present invention. FIG. 2 is a cross-sectional explanatory diagram showing a through-hole printed wiring board made by a conventional method. FIG. 3 is an explanatory plan view showing a state in which an opening is provided in a metal plate used in the present invention, and FIGS. 4 to 6 show other steps of inserting a prepreg piece into an opening in a metal plate in the present invention. It is a cross-sectional explanatory view showing an example. 1 is a metal plate, 2 is an opening, and 3 is a prepreg.

Claims (1)

[Claims] 1. After providing a large number of openings in a metal plate and inserting prepreg pieces cut from prepreg obtained by impregnating and drying a sheet-like base material with a thermosetting resin into the openings, A prepreg obtained by impregnating and drying a sheet-like base material with a thermosetting resin is layered on both surfaces of the metal plate, and a metal foil is placed on the outside of this prepreg, which is then heated and pressed to integrate. A method for producing a metal foil-clad laminate with a metal core, characterized by: 2. Form the opening in the metal plate by punching, and at this time, overlap the prepreg on the metal plate and punch it to form the opening and punch out the prepreg piece cut into the same shape as the opening. A method for manufacturing a metal foil-clad laminate with a metal core according to claim 1, wherein the insertion into the opening is performed in the same step. 3. When cutting out the prepreg piece together with the metal plate piece by punching, the cutout part is elastically held from the opposite side of the punching process, and then the cutout part is punched into the opening formed in the metal plate. The method for manufacturing a metal-core metal foil-clad laminate according to claim 2, wherein the cut prepreg piece is pushed back. 4. The length or diameter (a) before the opening provided in the metal plate is larger than the length (b) of the metal part between adjacent openings. A method for producing a metal-core metal foil-clad laminate according to any one of the items.