JPS60260330A - Manufacture of double-side metal lined flexible printed wiring substrate - 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 double-sided metal-clad flexible printed wiring board with excellent heat resistance.

(Prior art) Conventionally, flexible wiring boards are made by bonding a plastic film and a metal foil as a conductor by using an adhesive, or by applying a heat-resistant resin uniformly dissolved in a solvent directly onto the metal foil. It is manufactured by spreading and drying.

(The problem that BA is trying to solve) The former has gold on both sides of the plastic film! It is possible to manufacture a double-sided metal-clad flexible printed circuit board with 14 foils bonded together. However, even if polyimide film, which has excellent heat resistance, is used as a plastic film, it is difficult to use adhesive.
Heat resistance is inferior to polyimide film (260-280℃)
7 LexiPle printed wiring boards with excellent heat resistance have been in high demand due to their limited ability to withstand soldering.

Also, is the latter an adhesive? Since it is not used, flexible wiring boards with excellent heat resistance can be manufactured. However, since a solvent is used when applying VC resin on metal foil, is it possible to make a double-sided metal-clad flexible printed wiring board? Even if an attempt was made to manufacture it, it would be difficult to remove the bath agent and it would not be possible to manufacture it.

(Problem? Means for solving the problem) The inventors of the present invention have investigated various methods of manufacturing a double-sided metal-clad flexible wiring board with excellent heat resistance.As a result, the inventors have developed a method of coating a heat-resistant resin powder on a metal foil, and then coating the metal foil with a heat-resistant resin powder. The resin layers of the metal foil are stacked facing each other, and the heat-resistant resin is melted by applying heat and pressure between the rolls, which are heated to a temperature higher than the glass transition temperature and lower than the decomposition temperature of the heat-resistant resin used. The present invention was made based on the finding that a double-sided metal-clad flexible wiring board with excellent heat resistance can be produced by adhering the metal lining and folding.

Next, the present invention will be explained in detail.

The heat-resistant resin used in the present invention includes polyimide,
Polyimide resins such as polyesterimide, polyetherimide, polyamideimide, etc., which have an imide ring in the molecule, polyoxadiazole, polyparabanic acid, polyhydantoin, etc., can be used.

Also, if the production speed is extremely slow, will it become a prepolymer of polyimide resin? It is also possible to use

In the above-described heat-resistant resin, it is preferable that the difference between the glass transition temperature and the thermal decomposition temperature in a nitrogen atmosphere is 60° C. or more because the difference during production becomes large.

Further, as the metal foil used in the present invention, metal foils such as copper and aluminum that are normally used for flexible wiring boards can be used.

Heat-resistant resin powder on metal foil! As for how to equip it,
Method using electrostatic spray, method using electrostatic dynamic immersion bath,
Any coating method may be used in accordance with the present invention.

Further, the particle size of the heat-resistant resin powder coated on the metal foil is usually preferably 100 μm or less.

The thickness of the coated heat-resistant resin powder varies depending on the particle size of the powder used and the pressure and temperature during adhesion, but it is usually 5.
Manufactured with a thickness of 0 to 150 μm.

In addition, the true science and technology for thermal isotherm ■Display differential thermal balance TGD-30
The temperature was measured in a nitrogen atmosphere at a temperature increase rate of 5''C/min, and was determined by the tangential method.

Furthermore, the glass transition temperature is determined by the Vacuum Riko N System Mechanical Tester TM.
Used for A-1500 in tension mode, heating rate 10℃/m
Measured in.

The temperature at which the metal foil r is bonded may be higher than the glass transition temperature of the heat-resistant resin used and lower than the decomposition temperature, but it is preferably 40° C. or more higher than the glass transition temperature from the viewpoint of adhesion.

If it is lower than the glass transition temperature, f'i will not gradually increase and it will not be possible to manufacture a 7-lexiple printed wiring board r. Further, if the temperature is higher than the decomposition temperature, the resin decomposes, so that only flexible wiring boards with inferior characteristics can be manufactured.In the worst case, the shape of the flexible printed wiring board cannot be maintained.

The pressure when bonding metal foil varies depending on the bonding temperature and the heat-resistant resin used. s1 Usually 1 to 1000
kg/an'.

Also, the higher the bonding temperature, the lower the pressure, and the lower the bonding temperature, the higher the pressure used.

Examples and comparative examples are shown below.

Example 1 (Production method of polyimide resin powder) 32.2 g (0.1 mol) of 3.3', 4.4'-hair'') phenonetetracarboxylic dianhydride (BTDA),
4.4'diaminodiphenyl ether (DPE) 20,
0 g (o, i mol) and p- heated to 60 °C
The mixture was placed in a four-eye flask equipped with 680 gk of chlorophenol, a thermometer, a stirrer, and a nitrogen inlet tube, and the temperature was raised to 160° C. in about 1 hour while flowing nitrogen gas to uniformly dissolve the monomers. After reacting at 160° C. for 2 hours, the mixture was cooled to 70″G to obtain a polyimide varnish.

The obtained polyimide varnish was added to a water-methanol mixture (mixing ratio 1/1N) of 21 which was being stirred at high speed using a Niske homogenizer (manufactured by Nippon Seiki Seisakusho), and was allowed to precipitate on the resin. 12 (fat r) was separated by filtration. The separated resin was washed three times with a water-methanol mixture and then dried under reduced pressure to obtain a powdery polyimide. It was used to manufacture a monoke flexible wiring board. (Glass transition temperature was 280°C.) (M-transition method for 7 lexiple wiring boards) Approximately 65 μm thick rolled copper foil was coated by electrostatic spraying 60
The entire rim thickness was coated with polyimide powder.

Next, two pieces of copper foil coated with polyimide powder were stacked face-to-face and 1m/m apart between rolls heated to 650°C.
A flexible wiring board made of double-sided copper foil with a thickness of approximately 100 μm was manufactured at Inn's Toho.

Characteristics of the manufactured flexible wiring board as a printed wiring board are shown in Table 2. Example 2 A double-sided copper foil flexible wiring board was fabricated in the same manner as in Example 1, except that DDE 4.4'-(aminoneenoxy)diphenylsulfone 4A 2 g (0.1 mol) was used. Manufactured.

Table 1 shows the characteristics of the manufactured flexible printed wiring board.

Comparative Example 1 Commercially available polyamic acid varnish pyre 'ML'' (Dup
(trade name, manufactured by Ont) was cast and coated on a rolled copper foil with a thickness of 65 μm, and dried at 80° C. for 4 hours under reduced pressure to remove all common solvents.

Next, two sheets of copper foil coated with resin and a resin layer were stacked facing each other and placed between rolls heated to 350°C at 1 m/mi.
7 Flexible wiring board made of double-sided copper foil passed through at a speed of 11. Blisters occur in the places where the parts remain, and the flexible printing arrangement base can be used for testing! No board was obtained.

Comparative Example 2 Polyimide film with a thickness of 25 μm (Kapton HDup
ont product name) and 65μm rolled steel foil? A flexible printed wiring board made of double-sided steel foil with a thickness of approximately 100 μm was prepared by adhering using epoxy thread adhesive 1-2766 (trade name, manufactured by Nippon Bostic Co., Ltd.).

Characteristics of the manufactured flexible printed wiring board are shown in Table 1.

Test Method (1) Soldering Heat Resistance In accordance with JIS C-6481, the sample was immersed in a solder bath at 315°C for 6 seconds, then taken out and observed for appearance as ``7 cle J''.

(2 tensile/fi peel strength based on JIS C-6481, width 1 (1 mm sample)
◇ (5) Surface resistance Measured in accordance with JIS C-6481 0 (4) Dielectric breakdown voltage Measured in accordance with JIS C-2120.

(Effects of the invention) By adopting the manufacturing method as described above, f) a double-sided metal-clad flexible printing base with excellent heat resistance; Dear Commissioner of the Japan Patent Office, 1. Indication of the case 'Patent Application No. 118683 of 1982 2, Title of invention Method for manufacturing double-sided metal-clad flexible printed wiring board 3,
Relationship with the case of the person making the amendment Name of patent applicant (445) Hitachi Chemical Co., Ltd. 4, Agent
Person 5, s of the detailed description of the invention in the specification subject to amendment.

6. I-(s 15-”C5o on page 9, line 4 from the bottom of the statement of contents of the amendment)
)" is corrected to "l'-(515°C 30 seconds)".

150-

Claims (1)

[Claims] 1. Heat-resistant resin powder is coated on the metal foil, and then the resin # of the metal foil is coated with #hairs, stacked facing each other, and the glass transition temperature is higher than that of the heat-resistant resin used. A method for manufacturing a double-sided metal-clad flexible printed circuit board, characterized in that heat-resistant resin is melted and metal foil is bonded by applying heat and pressure between rolls heated to a temperature lower than temperature. 2. Glass transition temperature of heat-resistant resin! A method for manufacturing a double-sided metal-clad flexible printed wiring board according to claim 1, characterized in that the heat-resistant resin is melted at a temperature higher than 74 Q "C and then the metal foil is attached. 3. Heat-resistant resin 3. A method for manufacturing a double-sided metal-clad flexible printed wiring board as claimed in claim 1 or 2, characterized in that the material is polyimide.