JPS6173398A - Multilayer printed 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] [Industrial Application Field] The present invention relates to a multilayer printed circuit board, which has particularly good street adhesion, excellent mechanical and thermal properties, and surface properties, and high density. A multilayer printed base that can realize miniaturization and miniaturization.
Regarding the board, it is widely used in the electronic industry.

[Conventional technology]

In recent years, various printed circuit boards have been developed with the development of electronic materials such as ICs, LSIs, and power transistors. Printed circuit boards are usually divided into rigid boards, which are mainly made of phenol, epoxy, and composites, and flexible boards, which are characterized by flexibility. However, flexible substrates currently have disadvantages in that they are extremely expensive and difficult to use.

Recently, there has been a demand for electronic materials to be more compact, denser, and more integrated, and the trend is towards increasing capacity and chip size. With such increased integration and capacity, how to dissipate the heat generated from electronic components and circuits has become an important issue. In order to solve this problem, a so-called metal core printed circuit board, which has a metal plate as its core, was developed.Recently, methods of constructing a printed circuit board using an enameled steel plate have been researched, for example, JP-A-56-62389, JP-A-56
-88344, JP-A-57-10994, etc. 61. Printed circuit boards using these enameled steel plates have excellent mechanical and thermal properties, and also have excellent advantages such as being able to be processed into any shape before firing.

゛In order to eliminate the drawbacks of conventional printed circuit boards, the present inventors have developed a thin forsterite (Si) on a steel plate.
O,) invented a printed circuit board in which a base film was formed, an enamel layer was formed on the forsterite film, and a conductive pattern was adhesively formed on the enamel layer, and patent application No. 1983-
No. 126329.

Furthermore, the present inventors have developed an insulating coating layer formed by applying and baking a coating treatment solution containing phosphate and colloidal silica as main components on a forsterite coating layer coated on a steel plate, and the insulating coating layer. A novel printed circuit board having a conductive pattern adhesively formed thereon was invented and disclosed in Japanese Patent Application No. 58-251746.

After that, the inventors further conducted research and invented a printed circuit board with even better adhesion properties, machinability, and thermal properties.
, disclosed in Japanese Patent Application No. 59-72368. It has been found that this printed circuit board is particularly excellent when the steel plate used contains 1.0 to 4.5% Si. In this way, a steel plate containing Si is used as the base steel plate, a forsterite film is formed on it, and a coating treatment liquid containing phosphate and colloidal silica as main components is applied and baked on top of the forsterite film. By laminating the insulating coating layer and the enamel layer, either singly or simultaneously, and adhering a conductive pattern thereon, a printed circuit board with excellent adhesion could be obtained.

As described above, all of the printed circuit boards disclosed by the present inventors have extremely excellent characteristics required for printed circuit boards, and have also achieved some success in terms of adhesion of the coating layer to the base steel plate. I got it. However, the most important requirement in manufacturing such new printed circuit boards is to further improve the adhesion between the base steel plate and the forsterite coating layer.

In other words, a printed circuit board with excellent adhesion is extremely advantageous in terms of machinability and thermal properties, and an increase in the uses of printed circuit boards can be expected.

[Problem that the invention seeks to solve]

The purpose of the present invention is to focus on the fact that the base steel plate of a printed circuit board previously disclosed by the present inventors and the forsterite base film formed thereon have particularly excellent adhesion, It is an object of the present invention to provide a multilayer printed circuit board that meets the demands for multilayer, high density, and miniaturization, and has excellent adhesion and mechanical and thermal properties.

[Means and effects for solving the problems] This object of the present invention is achieved by the following two inventions. The gist of the first invention is as follows. That is, in a printed circuit board comprising a forsterite coating layer coated on a board and a highly conductive pattern adhesively formed on the top, phosphate and colloidal salts coated on the forsterite coating layer are used. An insulating coating layer and/or an e-green coating layer formed by baking a coating treatment solution containing 7 rica as a main component, and a 4. The present invention is a multilayer printed circuit board, characterized in that it has a conductive pattern, and the insulating coating layer and/or the enamel layer corrugated on the conductive pattern.

Next, the gist of the second invention is as follows. That is, in a printed circuit board comprising a forsterite coating layer on a steel plate and a conductive pattern adhesively formed on the top, phosphate and colloidal silica coated on the forsterite coating layer are used. an insulating coating layer and/or an enamel layer formed by baking a coating treatment liquid as a main component; a first conductive pattern adhesively formed on the i8 green coating and/or the enamel layer; the insulating coating layer and/or the enamel layer coated on one conductive pattern; the single or plural sets of the conductive pattern and the insulating coating layer laminated on the insulating coating layer and/or the enamel layer; A multilayer printed circuit board characterized by having a combination with/or an enamel layer.

The structure and operation of the present invention will be explained in detail with reference to the accompanying drawings.

The printed circuit board shown in FIG. 1 preferably has Si: 1.0 to
4. On the steel plate 2 containing s ' This printed circuit board is coated with an insulating film layer 6 formed by applying and baking a coating treatment liquid containing the main component, and a conductive pattern 10 is adhesively formed on the insulating film layer 6. -25174
This was disclosed in 6.

Thus, the insulating coating layer 6 formed on the forsterite layer 4 shown in FIG. 1 may be replaced with the enamel layer 8, or both may be laminated at the same time. In this case, the insulating coating layer 6A may be formed on the forsterite layer 4 formed on the steel plate 2, and the enamel layer 8 may be formed on it, or the enamel layer 8 may be formed on the forsterite layer 4 first. However, even if the insulating coating layer 6A is formed thereon, the effect is the same. This fact was disclosed in Japanese Patent Application No. 59-7236 by the inventors of the present invention.
As disclosed in 8. That is, the insulation coating layer 6
Either A or the enamel layer 8 may be laminated on the forsterite layer 4 alone or both may be laminated at the same time.In this case, it is more effective to make either one a thick insulating layer or a thin multilayer. The above patent application No. 7236/1986 was filed.
This was disclosed in 8. After the conductive pattern 10 was bonded to the uppermost layer in this manner, it was annealed at a temperature in the range of 300 to 1050°C to produce a conventional printed circuit board.

However, in the conventional printed circuit board as shown in FIG. 1, there is a risk that the conductive circuits may be interrupted by dust in the atmosphere or the like due to the recent increase in the density of integrated circuits. As shown in FIG. 2, an insulating coating 6B was further formed on the conductive pattern 10. As the insulating layer M6B,
Either an insulating coating layer or an enamel layer formed by applying and baking a coating treatment solution containing phosphate and colloidal silica as main components, or both may be used as a multilayer.

In order to achieve high density and miniaturization of printed circuit boards, the present inventors developed a 14q electrical pattern IO as shown in FIG.
A multilayer printed circuit board was invented in which a second conductive pattern IOB was bonded onto an insulating coating layer 6B formed on A, and an insulating coating layer 6C was further formed thereon. Although only a two-layer printed circuit board with conductive patterns IOA and 10B is shown in FIG. 3, either a single layer of the insulating coating layer 6A and the enamel layer 8 coated on the first conductive pattern IOA or both laminated simultaneously. It is possible to laminate two or more layers of a combination of a conductive pattern 1°, an insulating coating layer 6 and/or an enamel layer 8 on the multilayer formed by the printed circuit board, thereby increasing the density of the printed circuit board. It became possible to make it smaller.

The printed circuit board shown in Figure 4 shows an embodiment in which the multilayer coating layer shown in Figure 3 is applied to both the front and back sides of the steel plate 2, and is more dense and smaller than the printed circuit board shown in Figure 3. This makes it possible to

The multilayer printed circuit board shown in FIG. 5 is an example showing another embodiment of the multilayer printed circuit board according to the present invention shown in FIG. A floating layer 8 is formed on the insulating film layer 6B formed by coating and baking a coating treatment liquid containing rhoidal silica as a main component, and the first insulating film layer 6C is further formed thereon. This is a multilayer printed circuit board with two conductive patterns IOB bonded together and an insulating coating layer 6D formed thereon.

By using the multilayer printed circuit board according to the present invention shown in FIGS. 2 to 5 above, it is possible to achieve higher density and miniaturization than ever before, and to provide a printed circuit board that can fully meet recent demands. became possible.

As for the base steel plate used in the present invention, as already disclosed by the inventors in Japanese Patent Application No. 126329/1982
It is desirable that the steel plate contains i: 1.0 to 45%. In order to form a forsterite film on the surface of the steel plate, Si:l, 0, containing ~4.5% of Q,
A cold-rolled steel plate with a thickness of 1 to LOm is decarburized and primary recrystallized annealed in a wet hydrogen atmosphere at 600 to 900°C to form a Sin on the surface.
By forming a subscale mainly composed of , , and then uniformly applying an annealing separator mainly composed of 0 and annealing it, a thin 7 orsterite) (2Mll) is formed on the steel plate.
o・Sin,) is a method of forming a base film, but if the Si content in the steel plate is less than 1.0%,
Adhesion deteriorates due to the small amount of subscale produced, including Sin, which prevents the formation of a suitable forsterite film, and also when the Si content exceeds 4.5%, adhesion is considered to be poor. This is because an excessive amount of subscale containing , and Sin) will not form a good forsterite film. As the base steel plate, not only silicon steel plate but also stainless steel or other steel types can be used as long as the condition of containing Si: LO to 4.5% is satisfied.

〔Example〕

Example I On the steel plate 2 containing &O% of 8k, #0: s s%,
Serpentine: 35%, MnO: 5%, TiO2: 5X
1150 after applying an annealing separator containing slurry
It was annealed in N gas at 700° C. for 1 hour, coated with a coating solution containing Forsterei, and baked at 700° C. for 3 minutes to form an insulating film.

After adhering the first conductive pattern 10A onto this insulating coating layer 6A, it was annealed at 650° C. for 1 minute. After forming the same insulating coating layer 6B as above on this first conductive pattern IOA and bonding the second conductive pattern 10B thereon,
It was annealed at 50° C. for 1 minute, and an insulating coating layer 6C made of the same coating liquid as above was formed on the second conductive pattern IOB to form a multilayer printed board.

The resulting multilayer printed circuit board has approximately twice the density of conventional boards,
It was possible to achieve miniaturization, and its conductivity, insulation, and adhesion were good, and its thermal, mechanical properties, and surface properties were as good as those of conventional single-layer printed circuit boards.

Example 2 After applying an annealing separator mainly composed of K#O on a steel plate 2 containing 16% Si, the steel plate was heated at 1100° C.N.
The forsterite coating 4 was formed by annealing in gas for 1 hour. This Forstery and baking process was performed to form an insulating coating 6A. A first conductive pattern I is formed on this insulating coating layer 6A.
After adhering the OA, it was annealed at 700°C for 3 minutes.

The same insulating film layer 6B as above is formed on this 14th turtle pattern IOA, and a conductive pattern 71 is definitely formed on the film layer 6B.
A multilayer printed circuit board was manufactured by repeating the lamination of the combination of 0 and the insulating coating layer 6 twice.

The obtained multilayer printed circuit board can be three times more dense and smaller than conventional printed circuit boards, and has good conductivity, excellent adhesion, and thermal resistance. The mechanical properties and surface properties were also as good as those of conventional printed circuit boards.

〔Effect of the invention〕

As is clear from the above detailed description and examples, the multilayer printed circuit board according to the present invention has a base layer composed of a forsterite film formed on a steel plate, and a corner-nine film mainly composed of phosphate and colloidal silica. An insulating coating layer and/or an enamel layer formed by baking a liquid, a conductor bonded thereon, and a single or plural sets of the conductive patterns laminated thereon, and the insulating coating layer and/or the enamel layer. The multilayer printed circuit board of the second invention having a combination of layers has the following excellent effects due to its structure and operation.

(a) With the recent increase in the density of integrated circuits, it was possible to completely prevent the risk of conductive circuits being interrupted by thin dust or dirt in the atmosphere.

(b) Since the conductive pattern can be multi-layered through an insulating film, or multi-layered conductive patterns can be provided on the front and back sides of the base steel plate, it is possible to increase the density several times that of conventional printed circuit boards. The advantages of (c), (b), and (b) have made it possible to provide printed circuit boards that can meet the recent demands for higher density and smaller integrated circuits. In addition to the above effects, the adhesiveness to the base steel plate, the thermal and mechanical properties as a substrate, and the surface quality are comparable to those of the conventional printed circuit boards disclosed by the present inventors.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the structure of a printed circuit board conventionally disclosed by the present inventors, and FIGS. 2 to 5 are schematic cross-sectional views showing the structure and embodiments of a multilayer printed circuit board according to the present invention. 2... Base steel plate, 4... Forsterite coating layer, 6.6A, 513.6C, 6D... Insulating coating layer, 8...
...Wandering layer, 10, IOA, IOB... Conductive pattern agent Patent attorney Takeo Nakaji Figure 4 5th factor

Claims (2)

[Claims] (1) a forsterite coating layer coated on a steel plate;
An insulating film formed on the forsterite film layer by baking a coating treatment solution containing phosphate and colloidal silica as main components, in a printed circuit board having a conductive pattern adhered thereon. a conductive pattern adhesively formed on the insulating coating layer and/or the enamel layer, and the insulating coating layer and/or the enamel layer coated on the conductive pattern. Features a multilayer printed circuit board. (2) a forsterite coating layer coated on a steel plate;
An insulating film formed on the forsterite film layer by baking a coating treatment solution containing phosphate and colloidal silica as main components, in a printed circuit board having a conductive pattern adhered thereon. a first conductive pattern adhesively formed on the insulating coating layer and/or the enamel layer;
The insulating coating layer and/or the enamel layer coated on the first conductive pattern, and the single or plural sets of the conductive pattern and the insulating coating laminated on the insulating coating layer and/or the enamel layer. A multilayer printed circuit board characterized in that it has a combination of layers and/or enameled layers.