JPS6173302A - Method of producing resistor or circuit board with resistor - 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 an improvement in a method for manufacturing a resistor or a circuit board with a resistor.

Prior Art and Problems Figure 2 E shows an example of a circuit board with a resistor, where 1' is an insulating substrate, 3' is a resistor layer, R/ is a resistor part, 5' is a circuit conductor part, 4' indicates an insulating coating.

Conventionally, the following method is known as a method for manufacturing such a circuit board with a resistor.

First, as shown in FIG. 2A, a paste 2' containing palladium, which is a catalyst for electroless plating, is applied to the surface of an insulating substrate 1'.
is coated on the entire surface, and an electroless plated thin film 3' mainly composed of nickel is provided thereon as a resistive film. Next, place the parts other than those that should be used as circuit conductors (A in Figure 2).
Acid-resistant or alkali-resistant ink is applied by printing as a mesh resist 4' on the non-applied exposed area (Fig. 2B), and a circuit conductor part 5' is formed by electroless plating or electrolytic plating. Peel off the mesh resist 4' (Fig. 2 C), and apply heat-resistant ink 4/, a/ to the exposed portion of the resistive film that should be used as a resistor (R/, 87 portion in Fig. 2 EK) by printing. This is made into a permanent coating, and then the exposed unnecessary portions of the two-resistance film are removed by etching as shown in FIG. 2E.

However, in circuit boards with resistors obtained by this method, the insulation resistance of the insulating substrate surface exposed by etching the resistive film is considerably low, and the insulation between resistor patterns and circuit conductor patterns is insufficient. It is. Furthermore, when the mesh resist 4' is peeled off, the resistive film 3' may be eroded by the stripping liquid and the resistance value characteristics may deteriorate.

Purpose of the Invention The purpose of the present invention is to manufacture a circuit board with a resistor that maintains sufficiently high insulation resistance on the surface of an insulating substrate and has excellent properties such as resistance value characteristics, conductor adhesion strength, heat resistance characteristics, and moisture resistance characteristics. The present invention also includes the production of a resistor consisting of a resistor part of a predetermined shape and an electrode part, and hereinafter, the term "circuit conductor part" also includes the electrode part. .

Structure of the Invention A method for manufacturing a resistor or a circuit board with a resistor according to the present invention is a method for manufacturing a resistor or a circuit board with a resistor in which a resistor portion and a circuit conductor portion are formed in a predetermined pattern on an insulating substrate. , a paste containing an electroless plating catalyst is printed in the predetermined pattern on the insulating substrate, and after curing the paste, the insulating substrate is immersed in an electroless plating bath to perform electroless plating in the predetermined pattern. forming a resistor thin film, cover-coating the resistor part of the electroless plated thin film pattern with an insulating material, and performing electroless or electrolytic plating on the exposed electroless plated thin film pattern other than the resistor part, This method is characterized by forming the above electrode portion or circuit conductor portion.

Description of examples The present invention will be explained below with reference to the drawings.

In FIG. 1A, 1 is an insulating substrate, and 2 is a combined pattern of a resistor portion and a circuit conductor portion. After the paste is cured, the substrate is immersed in a nickel-based electroless plating bath and coated with nickel-based non-nickel in a pattern as shown in Figure 1B. Growing electrolytically plated thin films.

Next, as shown in FIG. 1C in this combined pattern, heat-resistant insulating ink 4 is applied to the resistor-equivalent portions (the portions that should be used as circuit resistors) by a photo process. Permanently cover.

This coating film serves as a cover coat for the thin film resistor as well as a resist for the copper plating that will form the circuit conductor portion in the next step.

After applying a permanent coating of insulating ink, the board was immersed indoors in dilute hydrochloric acid for several minutes to remove the oxide film on the surface of the thin film pattern, and then immersed in an electroless copper plating bath for galvanic treatment and exposed. A circuit conductor portion 5 is formed on the surface of the thin film pattern using an electroless copper plating film as shown in the first diagram.

After the oxide film is removed, only the surface of the thin film pattern may be activated by immersing it in a palladium-hydrochloric acid diluted solution, and then the electroless copper plating described above may be performed. This activation treatment with palladium can selectively deposit electroless copper only on the thin film pattern by keeping the concentration of the palladium solution below a certain concentration range. The palladium atom concentration range of palladium liquid is 1.4 x 10-' independent 4.2 x
10-' atoms/l.

Instead of the electroless plating method described above, it is also possible to apply electrolytic copper plating directly to the thin film pattern, and after performing the above electroless copper plating, it is also possible to further increase the plating thickness by performing electrolytic copper plating on top of it. can. In applications that require a relatively large current to flow through a circuit conductor, it is desirable to use a thick circuit conductor formed by electrolytic copper plating. However, in plating methods other than electroless plating activated by palladium, plating is performed by electrically connecting each pattern of the conductor to each other in some way, so after plating, drilling, drilling, etc. It is necessary to disconnect unnecessary parts by punching the mold or the like.

As is clear from FIG. 1E, which shows the e-e cross section of the first diagram, the circuit conductor portion 5 and the cover coat 4 are joined in a butt state. By applying a second cover coat 6 as shown in FIG. 1F to cover this abutment location, the resistor can be more completely covered. Figure 1 E and Figure 1 F
In the figure, l is an insulating substrate, 2 is a printed layer of paste containing an electroless plating catalyst, and 3 is a resistor made of an electroless plated thin film.

In the above, the insulating substrate may be a paper-phenol resin substrate, a paper-epoxy resin substrate, a glass-epoxy resin substrate, a metal support-synthetic resin surface-coated substrate, a ceramic substrate, or the like.

The composition of the palladium-containing paste is, for example, 100 parts of acrylonitrile butadiene rubber, 50 parts of phenol-formaldehyde resin, 20 parts of zirconium silicate, and 100 parts of acrylonitrile butadiene rubber.
Rika
5 Metallic Pd, Pdcl, etc. in a range of 1 to 7% by weight in terms of palladium element with respect to the resin composition
A bath containing PdI, Pd(N"3)2, and Pdo, and containing selonlupe acetate so that the solid content is 35 to 40% by weight is suitable. As an electroless plating bath for thin films, N1 -P, N1-C
o-P N1-Fe-P Ni-3n-P
N1-Zn-P, N1-W-P, Ni-Cr
, N1-B, or other nickel-based baths can be used. As a cover coat material for the thin film resistor that also serves as a Menki resist, an epoxy-based resin paste such as epoxy-imidazole can be used.

To start galvanic electroless copper plating on the exposed thin film pattern after applying Metsukiresist, contact a part of the thin film pattern with an iron piece, or perform instantaneous electrolysis using a battery or rectifier. It will be done. As a method of selectively activating the thin film pattern with palladium after coating the metskiresist, it may be immersed in the following treatment solution for 10 seconds at room temperature: Pd c120.1-0.31 37% HCl 1 oml Water 41. No more PdCl2
At a concentration of , copper plating may also be formed on the metal resist, which is not appropriate. A normal copper sulfate bath can be used as a bath for electrolytic copper plating directly on a thin film pattern or on an electroless copper plating film.

Next, examples of the present invention will be described.

Example 1 A palladium-containing ink having the following composition was screen-printed in a combined pattern on one side of a glass-epoxy resin substrate, and then cured by heating at 170° C. for 960 minutes.

Acrylonitrile butadiene rubber 100 parts phenol-formaldehyde ml Fr
50 g zirconium silica) 201 Silica 5 Metal Palladium 9I cellosolve acetate 340 This substrate was immersed in an electroless plating bath with the following composition, and plated under the following conditions to form a thin film on the patterned ink. was formed, then washed with water and dried.

Nickel chloride, hexahydrate: xor/g hydroxyacetic acid 39〃 Water oxide Thorium
20 Sodium hypophosphite
10 pPH 4.4 to 4.8 (20℃) Temperature 60℃ Plating time 60 seconds The components of the obtained thin film were 1゛1〕-P with a phosphorus content of 10%.
Met.

Next, an epoxy-based insulating ink (PC4OL manufactured by Photocircuit Co., Ltd.) was screen printed on the portions of the obtained N i -P thin film pattern corresponding to the resistor, covered, and then heated and cured at 130° C. for 60 minutes. Further, this board was immersed in 10% hydrochloric acid water at 25°C for 60 seconds and then washed with water, and then immersed in an electroless copper plating bath with the following composition and plated under the following conditions to remove the exposed N1-P pattern. After forming an electroless copper plating film on the surface, it was washed with water and dried.

Sulfuric acid copper 3oP#
Sodium hydrogen carbonate 30 l Sodium tartrate 1001 Sodium hydroxide 50 37% formalin solution 30rrLl/lPH1
1.5 (25° C.) Temperature: 25° C. Plating time: 50 seconds The plating was started by galvanic treatment using an external power source.

Furthermore, the same epoxy insulating ink as above was layered and screen printed to cover the resistor and electrode boundary.
After curing by heating in the same manner and further heating at 170° C. for 60 minutes to stabilize the characteristics of the resistor, unnecessary portions around the substrate were cut and removed using a mold to complete a circuit board with a thin film resistor.

The properties of the obtained resistor are as shown in the table below, and the insulation resistance of the exposed surface of the insulating substrate is 5X I O13 to 5X 10
”Ω.On the other hand, in the conventional method described above, 5
It was IO”Ω.

Table 1 Sheet resistance value 3QOΩ/mouth resistance temperature coefficient (-55℃~+120℃) + 70 ppm 7℃
Heat resistance (70℃, no load, resistance change rate after 500 hours) 0.5% Moisture resistance (40℃, equivalent humidity 95%, no load, resistance change rate after 24Ohr) 0.5% Solder heat resistance (260℃) , resistance change rate after immersion for 20 seconds)
0.3'? 6 Conductor adhesion strength 6
00? /an Example 2 The same palladium-containing ink as in Example 1 was screen printed on one side of a board made by applying epoxy paint to a thickness of about 50 μm on the surface of an aluminum plate to form a combined pattern of resistors and circuit conductors. It was formed and heat-cured under the same conditions. This substrate was immersed in an electroless plating bath having the following composition to form a similarly patterned ink-like thin film, which was washed with water and dried.

Sulfuric acid Ferrous 40 g/l Nickel sulfate hexahydrate 26 I Sodium citrate dihydrate 741 Sodium hypophosphite 21 1 Boron
Acid 30! PM(9,0(
25°C) Temperature: 90°C Plating time: 15 minutes The composition of the obtained thin film was N1-Fe-P.

Next, in the same manner as in Example 1, an insulating ink was printed on the portion corresponding to the resistor and cured by heating, and the exposed portion of the thin film pattern was similarly electroless copper plated for 5 minutes. In addition, as a starting treatment for electroless copper plating, palladium activation treatment according to the following formulation and conditions was adopted.

Palladium chloride 0.2? /l salt
Acid 101 Water 4g warm
Next, electrolytic copper plating was performed on the electroless copper plating film using a copper sulfate-based plating bath to give a conductor thickness of 20 μm. Next, the aforementioned epoxy insulating ink was layered and screen printed to cover the boundary between the resistor and the conductor, and unnecessary parts around the board were cut and removed using a mold to complete the circuit board with the resistor.

The characteristics of the obtained resistor were as follows, and the insulation resistance of the exposed surface of the insulating substrate was 5×10 13 to 5×10”Ω.

Table 2 Sheet resistance value 400 Ω/mouth resistance temperature coefficient (-55℃~+120℃) + 70 ppm
7℃ heat resistance characteristics (70℃, :aWatt/c++!Resistor area, resistance change rate after 500hr)
0.3% moisture resistance (40℃, equivalent humidity 95%)
Resistance change rate after 24 Ohr with no load) 0.5% Soldering heat resistance (resistance change rate after immersion at 260°C for 20 seconds) 0
．． 3% Conductor adhesion strength 600 f/an
Effects of the Invention As mentioned above, according to the method for manufacturing a resistor or a circuit board with a resistor according to the present invention, the resistor can maintain high insulation resistance on the exposed surface of an insulating substrate and has excellent conductor adhesion strength. Alternatively, a circuit board with a resistor can be manufactured. Furthermore, since there is no need to use a stripping solution, erosion of the resistive film by the stripping solution can be eliminated, and good resistance characteristics can be ensured.

[Brief explanation of the drawing]

Figure 1 A1 Figure 1 B1 Figure 1 C and the first diagram are explanatory diagrams showing the working procedure of the method for manufacturing a resistor or a circuit board with a resistor according to the present invention, and Figure 1 E is e in the first diagram. -e cross-sectional explanatory diagram, Fig. 1 F is an explanatory diagram showing another embodiment of the present invention, Fig. 2 A1 Fig. 2 81 Fig. 2 01 Fig. 2 and Fig. 2 E are conventional resistor-equipped diagrams. FIG. 3 is an explanatory diagram showing a working procedure of a method for manufacturing a circuit board. In the figure, 1 is an insulating substrate, 2 is a paste printing layer, 3 is an electroless plated resistive thin film, 4 is a cover coat, and 5 is a plated conductor layer. rノ(Br 0 Li2 Mi Sue

Claims (1)

[Claims] In a method for manufacturing a resistor or a circuit board with a resistor in which a resistor part and an electrode part of the resistor or a circuit conductor part are formed on an insulating substrate in a predetermined pattern, a paste containing an electroless plating catalyst is applied on the insulating substrate. After printing the paste in the predetermined pattern and curing the paste, the insulating substrate is immersed in an electroless plating solution to form an electroless plated resistor thin film in the predetermined pattern. The resistor part is cover-coated with an insulating material, and electroless or electrolytic plating is performed on the exposed electroless plating thin film pattern other than the resistor part to form the above-mentioned electrode part or circuit conductor part. A method for manufacturing a resistor or a circuit board with a resistor.