JPS62238680A - Printed wiring 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 the Invention The present invention relates to a printed wiring board containing mica as a main component, which has improved properties such as dimensional stability.

Conventional technology A printed wiring board is a board in which an electrical circuit is formed with a thin conductive strip inside or on the surface of an insulating board, and electrical components can be connected to and mounted on it. It is widely used in industrial electrical equipment such as computers and computers.

Since it is preferable for these devices to be made compact, printed wiring boards that can mount a large number of electrical components, so-called high packaging density, have come into use.

In this way, printed wiring boards with electrical components mounted on them are used in various types of equipment, and they must be finished compactly.Furthermore, in order to reduce production costs, the printed wiring board manufacturing process and subsequent electrical As the process of soldering components becomes automated, the performance required of printed wiring boards is also increasing.

For example, when attaching electrical components such as resistors and capacitors to a printed wiring board with a circuit pattern formed on copper foil pasted on the surface of a laminate, the leads or, in the case of chi-knob components, the electrodes are connected to the circuit pattern. Soldering is performed by soldering to lands, and in automatic soldering, the device temporarily attaches electrical components to a printed wiring board and brings the soldering parts into contact with molten solder. At this time, the temperature of the molten solder reaches as high as 250°C, so the temperature difference between the side of the printed circuit board in contact with it and the opposite side can be more than 100°C, resulting in the solder melting on the printed circuit board Ia. This may cause misalignment of electrical components and may not be soldered in a predetermined location. This results in defective soldering that must be corrected manually, resulting in a significant drop in production efficiency, and countermeasures are required.

In order to meet these demands, conventional printed wiring boards have been used, which are made by laminating and heat-pressing glass fiber cloth impregnated with epoxy resin, but the soldering method described above has sufficient resistance to warping over time. cannot be prevented. Similar problems also exist with other types of printed circuit boards that require even higher dimensional stability.

Problems to be Solved by the Invention As mentioned above, the conventional printed wiring board has problems, particularly in terms of its dimensional stability. Therefore, in a previous application, we proposed a printed circuit board made of a laminate using mica. In this case, if mica pieces are exposed on the surface of the laminate, they may peel off, and when drilling holes in the laminate, the edges may become rough or cracks may occur. Complete measures are desired.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a mica layer containing mica and resin as main components and/or a mica body in which this mica layer is formed on a base material, and The present invention provides a printed wiring board characterized by having a resin-impregnated base material impregnated with a resin and a mica laminate material laminated with the resin-impregnated base material on one or both of the outer sides.

Next, the present invention will be explained in detail.

In the present invention, when a base material is impregnated with a resin or a mica layer containing mica and resin as the main components is formed on the base material, examples of the base material include glass cloth, glass nonwoven fabric, polyester cloth, polyester nonwoven fabric. ,
Other non-woven fabrics, films, aramid paper, paper, etc. may be used.

The mica used in the present invention is either so-called calcined laminated mica, which is obtained by burning mica raw ore at about 750°C to remove some of the crystal water, and then pulverizing it, or so-called uncalcined laminated mica, which is pulverized without burning. can also be used, or can be used in combination. Moreover, both soft and hard mica can be used, and these can also be used in combination. In addition to these laminated mica, the above-mentioned fired,
Either unfired mica pieces, hard mica pieces, or soft mica pieces can be used. Synthetic mica can also be used.

When forming a mica layer containing mica and resin as the main components without a base material, these mica pieces are made into paper by the same method as paper making, and usually about 2
It is preferable to use a composite mica using mica below vnrd.

In the present invention, a resin is used, but either a thermosetting resin or a thermoplastic resin can be used as such resin, and both can also be used in combination.

Examples of thermosetting resins include epoxy resins and phenol resins. As the epoxy resin, bisphenol type, brominated bisphenol type, novolac type, cycloaliphatic type, and glycidyl ester type can be used alone or in combination of two or more. The curing agent used in this case includes a latent curing agent, acid anhydride, aliphatic polyamine, polyamide resin, Lewis acid complex compound, phenol resin, dicyandiamide, tertiary amine, imidazole, aromatic amine, isocyanate, and the like.

Polyimide resins and triazine resins are also used when heat resistance is required for printed wiring boards.

These pure resins have glass transition temperatures as high as 300°C.

Polysulfone (U), which has high heat resistance, is used as a thermoplastic resin.
(manufactured by CC Corporation), polyether sulfone (manufactured by IC1 Corporation), polyetherimide (manufactured by GE Corporation), etc. are also used.

The printed wiring board of the present invention may further contain other components mentioned above. Examples include aluminum hydroxide, magnesium hydroxide, calcium carbonate, and alumina.

In order to manufacture the printed wiring board of the present invention, as shown in FIG. The mica body 2 formed by coating or impregnation is laminated by hot pressing to create a mica laminate 3. Alternatively, as shown in FIG. 2, the resin-impregnated base material 1 is obtained by impregnating the base material with the resin, and the mica is coated or impregnated with the resin, or the mica is formed by molding a mixture containing resin and mica as main components. Layer 4 is laminated by hot pressing to form mica laminate material 5. At this time, when using mica, if the resin is thermosetting, heat it to a semi-cured state (B
It is preferable to make a so-called pre-preg mica sheet into a mica laminate by hot pressing it. In this way, in the mica body 2 and the mica layer 4 using assembled mica, the resin contained in the mica softens and flows and fills the gaps between the mica pieces, so that they are integrated. At this time, the amount of mica contained in the prepreg mica sheet of the mica body 2 is preferably 5 to 60% by weight based on the total amount of the resin and mica flakes.

In addition, when laminated mica is used, the amount of resin contained in the prepreg mica sheet of mica layer 4 is 15 to 50% by weight in the case of a fired mica sheet, and 15 to 50% by weight in the case of an unfired mica sheet, based on the total amount with mica. A suitable amount is 10 to 40% by weight. Such a prepreg mica sheet uses a thermosetting resin, but in the case of a thermoplastic resin, if a solvent solution thereof is used, it is impregnated and then dried. Although the resin was impregnated in the above example, it may also be coated.

Although the above is a two-layer structure consisting of the resin-impregnated base material 1 and the mica body 2, it is also possible to form a mica laminate material 3° in which a plurality of mica bodies 2 are laminated as shown in FIG. As shown in Figure 4, a resin-impregnated base material 1 is further laminated to form a mica laminate material 3'° having resin-impregnated base materials 1.1 on both sides of the laminate of mica bodies 2.2... Although not shown, the same applies to the resin-impregnated base material 1 and the mica layer 4. In these cases, the resin-impregnated base material 1 is provided in a laminate of the mica body 2 and the mica layer 4, A structure in which the mica laminated materials 3.5 of each of FIGS. 1 and 2 are laminated,
Any structure that combines these appropriately may be used. When the surface of the mica laminate is constructed of the resin-impregnated base material in this way, even if a hole is made in the mica laminate, the edges of the surface will not be roughened or cracked.

Such laminated prepreg mica sheets can be used to create various types of printed wiring boards, including not only those with a circuit pattern formed on one or both sides, but also those with a multilayer structure that has a circuit inside. Various processes are applied to the printed wiring board depending on the type of material, but for example, if a circuit pattern is formed only on one side and a bisphenol type epoxy resin is used as the resin, 5 ~15 sheets stacked, 10Kg/c
d~40Kg/cot pressure, 140℃~180℃
, it is preferable to heat for 30 minutes to 2 hours. In addition, when manufacturing the printed wiring board of the present invention, a metal foil may be bonded to the surface of the laminate under pressure at the same time when the laminate is formed. As the metal foil in this case, copper foil, brass tube, aluminum foil, nickel foil, stainless steel foil, etc. can be used.

In the above, a prepreg mica sheet was used, but a so-called dry mica sheet with the amount of resin impregnated reduced to 1/10 to 1/3 can also be used. This is printed! F
When manufacturing the mica laminate material for the No. 51 substrate, the insufficient resin is impregnated with vacuum pressure and heated.

In this way, the mica layer, whose main components are mica and resin, is arranged so that it overlaps in a plane, especially in laminated mica, because the mica is in the form of flakes, and as a result, it has excellent heat resistance properties as well as the mica itself. This is considered to indicate dimensional stability.

Example Next, the present invention will be explained in detail.

Example 1 A glass cloth (manufactured by Nittobo Co., Ltd., thickness: 0.18 mm) was coated with a resin solution of the following composition and impregnated, and dried by heating at 120"C to obtain a glass prepreg sheet with a thickness of 0.3 m. form.

AER661 (epoxy resin manufactured by Asahi Kasei Corporation) 60 parts by weight Δ
EII 331 (Epoxy resin manufactured by Asahi Kasei Co., Ltd.) 40 parts by weight Boron trifluoride monoethylamine 3 parts by weight Methyl ethyl ketone 40 parts by weight Also, in the same manner as above using the resin solution of the following composition on the above glass cloth, a thickness of 0.4 A glass prepreg mica sheet of m is formed.

AER661 (same as above) 60 parts by weight AER331 (same as above) 40 parts by weight Boron trifluoride monoethylamine 3 parts by weight Hard unfired mica flakes 65 parts by weight Methyl ethyl ketone 110 parts by weight Six of the above glass prepreg mica sheets are stacked, and then A total of 8 sheets are stacked with glass prepreg sheets at 20Kg/ant.
The material was heated and pressed at 180° C. for 60 minutes to form a mica laminate 3 having a thickness of about 21 mm as shown in FIG. 4. Note that these are summarized in Table 1.

Table 2 shows the results of measuring various performances of the thus-prepared product using the measuring method described in JIS C6481. Note that when a printed wiring board has copper foil on its surface, the copper foil is hot-pressed at the same time, but in this case, measurements were taken on a board that does not use this copper foil.

Example 2 A mica laminate material for a printed wiring board of Example 2 was produced in the same manner except that the items listed in the Example 1 column of Table 1 were changed to the items listed in the Example 2 column. Regarding this as well, Table 2 shows the performance measurement results.

Example 3 A slurry of hard unfired laminated mica flakes (average particle size of about 500 μm) is prepared and used to produce laminated mica foil with a thickness of about 150 μm using a long-length paper machine using a conventional paper-making method. A bisphenol-type epoxy resin adhesive having the following composition was applied to the mica foil and impregnated, and the resin was added to the mica in an amount of about 30 fi% and heated to 120°C.
Heat it up. This completes a prepreg mica sheet.

^ER661 (epoxy resin manufactured by Asahi Kasei Corporation) 60 parts by weight A
ER331 (epoxy resin manufactured by Asahi Kasei Corporation) 40 parts by weight Boron trifluoride monoethylamine 3 parts by weight Methyl ethyl ketone 200 parts by weight Eight of these prepreg mica sheets were stacked, and the glass prepreg sheets prepared in Example 1 were stacked one above the other. 20Kg/
Heat and press at 180°C for 60 minutes using CD. As a result, a mica laminate material for a printed wiring board having a weight of 3100 g/rrr and a thickness of about 1.6 mm was produced. These are summarized in Table 3. Table 4 shows the measurement results for this as well, which were measured in the same manner as above.

Example 4 A mica laminate material for printed wiring boards was produced in the same manner as in Example 3 except for the matters described in the column of Example 4 in Table 2, and the measurement results thereof are also shown in Table 4 in the same manner as above. .

(Margins below this page) Table 1 (Margins below this page) Table 2 Table 3 (Margins below this page) Table 4 Effects of the invention As explained above, the present invention has a mica layer containing mica and resin as main components. It is possible to provide a printed wiring board with a mica laminated material using a resin-impregnated base material with a resin-impregnated base material on the outside, so that it is heat resistant even if it comes into contact with molten solder when soldering electrical components, for example. Not only can the mica be prevented from warping and maintain high dimensional stability, but since the mica is not exposed, it will not peel off, and when drilling holes, the edges will not be rough or cranked. Mica also has high insulation resistance, so it can exhibit excellent performance as a printed wiring board.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an explanatory diagram showing an example of a specific structure of the mica laminate material according to the present invention, and FIGS. 2 to 4 are respectively the second, third, and fourth examples thereof. It is an explanatory diagram. In the figure, ■ is a resin-impregnated base material, 2 is a mica body, 3.3゛, 3
°', 5 is a mica laminate material, and 4 is a mica layer. Patent filed on April 1, 1986. Person: Japan Mica Manufacturing Co., Ltd.
Patent Attorney Tadashi Sano Figure 1, Figure 2

Claims (1)

[Claims] (1) Mica layer and/or containing mica and resin as main components
Or, it has a mica laminate material in which a mica body with this mica layer formed on the base material and a resin-impregnated base material in which the base material is impregnated with a resin are laminated such that this resin-impregnated base material is on the outside of one or both. A printed wiring board characterized by: