JPH0685463B2 - Printed wiring board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a printed wiring board.

[Conventional technology]

Various attempts have been made to meet various demands for printed wiring boards in view of the widespread development and application of electronic technology in recent years, and there are also demands for fine patterning, multilayer wiring boards, three-dimensional three-dimensional wiring, etc. ing. As a characteristic of resistance formation, generally, as shown in FIG. 5, a circuit pattern 13 is formed by etching on a copper clad laminate on a circuit board, and then a photo printing method or a screen is formed on a printed wiring board 11. A carbon paste is printed on the upper layer of the circuit pattern 13 formed by a printing method or the like by screen printing, and the resistance 12 is formed by curing the carbon paste, and then solder resist printing or symbol printing is performed to form the component hole and the outer shape. It was completed by punching with a die.

[Problems to be solved by the invention]

However, in the conventional printed wiring board of this kind, the carbon thickness printed by the carbon paste printing on the upper layer of the pattern on the substrate is not uniform, and the resistance 12 is likely to fluctuate (about ± 5%). Since the resistance value was not constant, there was a repair work in which the individual resistances 12 were artificially adjusted by trimming work and then put into the target resistance value. The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a printed wiring board in which required resistance can be arranged without requiring repair work such as trimming.

[Means for solving problems]

The printed wiring board of the present invention is a printed wiring board comprising a circuit board, a circuit pattern formed on the circuit board, and a resistor formed using a photocurable carbon laminate film between the circuit patterns. In the plate, a resist layer for previously obtaining the strength and stability of the resistance is provided under the resistance formed of the photocurable carbon laminate film between the circuit patterns.

[Action]

According to the present invention, in forming a resistor, a carbon laminate film having a predetermined thickness is coated on an upper layer of a circuit pattern on a printed wiring board, and the film is developed and cured to distribute a required resistance between required joint portions of the circuit pattern. The resistance value required for each resistance is made uniform, and the strength and stability of the resistance formed by using the carbon laminate film are obtained.

〔Example〕

 The present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a printed wiring board, 2 is a photo-curable carbon laminate film coated on the upper side of a circuit pattern 3 formed by a method described later, and 3 is a single-sided copper clad laminate laminated on the printed wiring board 1. The circuit pattern 4 formed by using the copper foil of the plate A by etching means is formed to obtain the strength and stability of the resistor 6 formed between the joints 3-1 and 3-2 between the circuit patterns 3. The resist 6 is a resistor formed on the upper side of the resist 4 between the joint portions 3-1 and 3-2 of the circuit pattern 3 by developing and curing the carbon laminate film 2 and removing unnecessary portions.

Further, a method of manufacturing the printed wiring board shown in FIG. 1 will be described in detail with reference to the process diagrams of FIGS. 2 to 4. In FIG. 2, A shows a single-sided copper-clad laminate formed by depositing 35 μ of copper foil 5 on one surface of the printed wiring board 1.
Then, the copper foil 5 of the single-sided copper-clad laminate A is baked with an etching resistant resist by screen printing at 80 ° C. for 3 minutes, and then a portion other than a desired circuit is removed by an acid etching solution of ferric chloride to remove the circuit. Patterns 3-1 and 3-2 are formed (see FIG. 3). Then, the circuit pattern 3-1
After forming the resist layer 4 by resist printing between the circuit pattern 3-2 and the circuit pattern 3-2, the upper side of the circuit pattern 3-1 and 3-2 is covered with the photocurable carbon laminate film 2,
After developing and curing this, unnecessary parts are removed, and the resistor 6 having a desired resistance value is connected to the junction parts 3-1 and 3 of the circuit pattern 3.
-2 (see FIG. 4a). After that, the required solder resist printing, symbol printing, etc. are performed on the printed wiring board 10 and the component holes and the outer shape are punched with a die to complete the production of the intended printed wiring board (see FIG. 4b). ).

〔The invention's effect〕

As described above, the present invention provides a circuit board, a circuit pattern formed on the circuit board, a resist formed between the circuit patterns, and a photocurable carbon laminate film on the circuit pattern and the resist. And the resist layer between the circuit patterns improves the strength and stability of the resistors provided on the upper side of the circuit pattern, and the resistors disposed between the junctions of the circuit patterns. Is a photo-curing type carbon laminate film coated on the upper layer of the circuit pattern that is developed and cured, so the thickness, width and length are more accurate and uniform compared to the resistance due to carbon paste printing, and repair by trimming is performed. It is possible to adjust the resistance value to a predetermined value without the need for the like and to provide a printed wiring board with high product accuracy. That.

[Brief description of drawings]

FIG. 1 is a sectional view of a printed wiring board showing an embodiment of the present invention, and FIGS. 2 to 4 are sectional views showing respective manufacturing steps for explaining a method of manufacturing a printed wiring board according to the present invention. FIG. 5 is a sectional view of a conventional printed wiring board. 1, 11 ... Printed wiring board 2 ... Photocurable carbon laminate film 3, 13 ... Resistive joint part of circuit pattern 3-1, 3-2 ... Circuit pattern 4, 14 ... Resist 5 ... Copper foil 6, 16 ... Resistor 10 … Printed wiring board A… Single-sided copper clad laminate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirotaka Kokonoki 1106 Fujikubo, Miyoshi-cho, Iruma-gun, Saitama Prefecture Japan CMC Co., Ltd. (72) Inventor Norihi Mukai 1106 Fujikubo, Miyoshi-cho, Iruma-gun, Saitama Nihon CMK Co., Ltd. (56) Reference JP 59-113602 (JP, A) JP 60-85592 (JP, A) ) JP-A-59-175787 (JP, A) JP-B 57-41838 (JP, B2) JP-B 55-16385 (JP, B2) JP-B 55-41546 (JP, B2)

Claims (1)

[Claims] 1. A printed wiring board comprising a circuit board, a circuit pattern formed on the circuit board, and a resistor formed of a photocurable carbon laminate film between the circuit patterns. A printed wiring board comprising a resist layer for obtaining the strength and stability of the resistance, which is previously provided under the resistance formed of a photocurable carbon laminate film between the circuit patterns.