JPS6292391A - Printed circuit 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 preferred that these i-devices 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 chip components, the electrodes are soldered to the circuit pattern. is carried out by soldering to lands, and in this case, automatic soldering is carried out using an apparatus in which electrical parts are temporarily attached to a printed wiring board and the soldering parts are brought 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 wiring board in contact with it and the opposite side may be more than 100°C, resulting in warping of the printed wiring board. However, misalignment of the electrical components may occur and the soldering may not be carried out at 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. Problems also exist with other types of printed wiring boards that require even higher dimensional stability.

Problems to be Solved by the Invention As described above, conventional printed wiring boards have problems, particularly in terms of dimensional stability, and improvement thereof has been desired.

Means for Solving the Problems In order to solve the above problems, the present invention provides a printed wiring board characterized by having a mica sheet having a mica layer containing mica and resin as main components as a base material. It is something to do.

Next, the present invention will be explained in detail.

In the present invention, the base material has a mica layer mainly composed of mica and resin, and this base material functions as a backing material. non-woven fabric,
Other non-woven fabrics, films, aramid paper, etc. are also used.

The mica of the mica layer in the present invention includes so-called calcined mica, which is a type in which mica raw ore is calcined at, for example, about 750°C to remove some of the crystal water, and then crushed, and so-called uncalcined mica, which is crushed without baking. Any of these can be used, or they can be used in combination. Moreover, both soft and hard mica can be used, and these can also be used in combination. It is preferable to use these mica as mica flakes, and in this case, it is also possible to decompose the assembled mica made into paper and use it as mica flakes.

As the resin used in the present invention, either a thermosetting resin or a thermoplastic resin can be used, 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), polyether sulfone (manufactured by CI), polyetherimide (manufactured by GE), 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.

To manufacture the printed wiring board of the present invention, as shown in FIG. 1, the base material 2 is coated with or impregnated with a mica resin mixed layer 1 made by mixing mica resin with the above resin. At this time, if the resin is thermosetting, heat it to a semi-cured state (
B stage), a so-called prepreg mica sheet is formed.

These prepreg mica sheets and the like are laminated and hot pressed to form a laminate for a printed wiring board. When heat-pressed in this manner, the resin softens and flows, filling the gaps between the mica particles and integrating them. Furthermore, as shown in FIG. 2, it is also possible to laminate the prepreg mica sheet or the like with a composite mica sheet 3 such as a prepreg composite mica sheet made by impregnating the composite mica with a resin and bring it into a semi-cured state, and then heat press the laminated mica sheet 3. be called. The mica resin mixed layer 1 and the mica resin assembly 1-3 can be used in any combination and arrangement, and the base material can also be used in any combination and arrangement. Note that the resin layer itself can be used in the same manner as these, and the present invention also includes this.

In the above, the mixing ratio of the mica scale pieces to the resin in the mica resin mixed layer is preferably 5 to 60% by weight. In addition, the amount of resin contained in prepreg mica sheets using laminated mica is 15 to 50% in the case of fired laminated mica sheets.
% by weight, preferably 10 to 40% by weight in the case of unfired laminated mica sheets. In these cases, if the ratio of resin is too high, the properties of mica will not be expressed well, and if mica is too large, it will become dangerous.

Such pre-preg mica sheets etc. can be used for various types of printed wiring such as printed circuits with circuit patterns on one or both sides, (not only boards but also multi-layer structures with circuits inside), ( Various processes are applied to create the board and it is molded into a printed YA board, but for example, a circuit pattern is formed only on one side, and a bisphenol-type epoxy resin is used as the resin. In the case of objects, 5 to 15 layers are laminated,] OKg
/cJ~40Kg/cJ pressure, 140°C~18
It is preferable to manufacture the laminate by heating at 0° C. for 30 minutes to 2 hours. Note that a metal foil may be bonded to the surface of the printed wiring board laminate of the present invention under pressure at the time of molding. As the metal foil in this case, copper foil, brass foil, 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 produced by impregnating the insufficient resin with vacuum pressure when producing a laminate for a printed wiring board, and then heating it.

A layer containing mica is formed as described above,
Since mica is a flake, it is arranged so as to overlap on a plane, and it is thought that it exhibits excellent dimensional stability in combination with its good heat resistance.

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

Example 1 A glass cloth (manufactured by Nittobo Co., Ltd., thickness 0.I n+) was coated with a resin solution of the following composition and impregnated, and heated and dried at 120°C to produce a glass prepreg mica sheet with a thickness of 0.15 mm. form.

AI! R661 (epoxy resin manufactured by Asahi Kasei Corporation) 60 parts by weight AER33N epoxy resin manufactured by Asahi Kasei Corporation) 40 parts by weight Boron trifluoride monoethylamine 3 parts by weight Hard uncalcined mica resin pieces 40 parts by weight Methyl ethyl ketone
200 parts by weight 16 sheets of this glass prepreg mica sheet were stacked and heated at 20Kg/cd at 180°C160.
Heat for a minute. As a result, a printed wiring board laminate as shown in FIG. 1 with a basis weight of 2705 g/rrr and a thickness of about 1.6 mm was produced. Note that these are summarized in Table 1. Table 2 shows the results of measuring various performances of the thus-prepared product using the measurement method 9 specified in JIS C64.

Note that when a printed wiring board has copper foil on its surface, the copper foil is hot-pressed at the same time as the laminate, but in this case, measurements were taken on a board that does not use this copper foil.

Example 2 A printed wiring board laminate as shown in FIG. 1 of Example 2 was produced in the same manner except that the matters described in the column of Example 1 in Table 1 were changed to the matters described in the column of Example 2. Created. Regarding this as well, Table 2 shows the performance measurement results.

(1 inch below this shell margin) Table 1 Similar below this page margin] Table 2 Effects of the invention As explained above, the present invention has a mica sheet having a mica layer containing mica and resin as the main components as a base material. Since a printed wiring board can be provided, it is possible to maintain high dimensional stability, such as exhibiting heat resistance and preventing warping even if it comes into contact with molten solder when soldering electrical components, for example. Mica also has high insulation resistance, so it can exhibit excellent performance as a printed wiring board.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one example of a specific example of a mica layer according to the present invention, and FIG. 2 is an explanatory diagram of another example. In the figure, 1 is a mica resin mixed layer, 2 is a base material, and 3 is a prepreg assembled mica sheet. October 18, 1985 Figure 1 Procedural amendment stamp button November 12, 1985 Director General of the Patent Office Michibu Uga 1, Indication of the case 1985 Patent Application No. 230960 2, Name of the invention Printed wiring Substrate 3. Relationship with the case of the person making the amendment Patent applicant 2-4-1 Marunouchi, Chiyoda-ku, Tokyo Japan Mica Manufacturing Co., Ltd. Representative Tsutomu Yokoyama 4, Agent ■105 6. Inventions increased by amendment No. 11 On page 9, line 15, the phrase "U this glass prepreg mica sheet" is corrected to "this glass prepreg mica sheet (Figure 1)". (2) On page 9, lines 17 and 18 of the specification, the phrase "a laminate for a printed wiring board as shown in FIG. 61IIn printed wiring board laminate
I am corrected. (3) On page 10, lines 8 to 10 of the specification, the phrase "laminate J for printed wiring boards as shown in FIG. 1 of Example 2" is replaced with "laminate J for printed wiring boards as shown in FIG. 1 of Example 2 "Laminated board for printed wiring board made of prepreg mica sheet". Written amendment to the above procedures (April 11, 1988, Mr. Michibe Uga, Director General of the Patent Office of the own ship, 1, Indication of the case, Patent Application No. 230960 of 1985, 2, Name of the invention, Printed wiring board 3, Person making the amendment) Relationship with Patent Applicant: 2-4-1 Marunouchi, Chiyoda-ku, Tokyo Japan Mica Manufacturing Co., Ltd. Representative: Sei-ro Yokoyama 4, Agent ■105 Miki Building 5, 2-2-10 Nishi-Shinbashi, Minato-ku, Tokyo Date of amendment order Motto 6. Subject of amendment ``Column for detailed explanation of the invention in the specification'' 7. Contents of amendment (1) In lines 7 to 9 of page 7 of the specification, [mica flakes] ..." is corrected to "The mixing ratio of mica scale pieces is preferably 5 to 60% by weight based on the total amount of needles with resin." (2) Specification, page 9, 14. In the line that says "200 MW parts of methyl ethyl ketone",
Correct it to "100!i parts of methyl ethyl ketone." (3) Table 1 on page 11 of the specification is corrected as follows. Table 1

Claims (1)

[Claims] 1) A printed wiring board characterized by having a mica sheet on which a mica layer containing mica and resin as main components is formed as a base material.