JPS58107606A - Method of producing chip 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] The present invention relates to a method for manufacturing a chip resistor, and aims to provide a method for manufacturing a glazed chip resistor that is inexpensive, has excellent solderability, and is easy to mass produce. .

Conventionally, in a glaze type chip resistor, Aq-Pd type baked electrodes 4 are formed on both ends and both sides of a heat-resistant insulating substrate 1 made of alumina or the like, as shown in the cross-sectional structure in Fig. 1.
A glaze resistor 2 made of ruthenium oxide or the like is formed by baking in the center, and a protective coat 3 is applied on the resistor 2.

In addition, the Aq-Pd-based electrode 4 is coated with a tertiary electrode plating coat 5 of F, Ni, or 3B to prevent solder corrosion during soldering. .

As is clear from the above configuration, the conventional chip resistor has many drawbacks as shown below. In other words, it takes a lot of man-hours to manufacture and is difficult to mass produce.
Although the cost of baked-on electrodes is high, and the problem of "solder erosion" during soldering has been considerably improved, there are still concerns about this depending on the soldering conditions, and there are problems with Aq migration. etc.

The present invention provides a method for manufacturing a chip resistor that eliminates the above-mentioned drawbacks, and includes a Pd component in the electrode portion including the ends and each end face of the glaze resistor film provided at required locations on a heat-resistant insulating substrate. After applying and drying a paste containing Pd, fine Pd metal particles are precipitated in this area by heat treatment, and plated electrodes are formed thereon by electroless plating to form a chip resistor.

Depending on the case, a plating of Sn or 5n-Pb is further formed thereon), so that the fear of "solder erosion" during soldering, which is one of the major problems in the prior art, can be resolved.

In addition, conventional Aq and Pd electrodes suffer from the above-mentioned "solder erosion".
In order to prevent this, secondary electrodes and tertiary electrodes are formed, but in the present invention, the electrodes formed by electroless plating alone can be put to practical use, so a reduction in the number of man-hours is expected. In addition, conventional Aq-Pd-based electrodes have a high cost, which has become an even bigger problem due to the recent rise in the price of precious metals, but in the present invention, base metals such as Ni, Cu; Because it uses
Significant cost reductions can be achieved. Furthermore, Aq-Pd
Since there is a risk of Aq migration in the electrode,
Although improvement is desired, there is no such concern in the present invention.

Next, the configuration of the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a sectional view showing an example of a chip resistor obtained by the method of the present invention.
' is a heat-resistant insulating substrate, usually an alumina substrate, whose surface is roughened by polishing or chemical etching in a hydrofluoric acid-nitric acid mixture to improve the adhesion of the plating film. Reference numeral 12 denotes a glaze-based resistive film, which is usually made of ruthenium oxide. This glazed resistor paste is printed on the required locations by screen printing, and after drying, it is fired at around 860"C to form the resistive film. 14 is Pd, which serves as the catalyst nucleus for electroless plating.
This is a metal fine particle layer, which is made by applying an active paste containing a Pd component to the electrode portion including the ends and each end face of the glaze resistance film, drying it, and heat-treating it to apply P to the surface of the electrode portion.
d It is precipitated as fine metal particles.

The Pd components in this active paste include fine Pd powder with a particle size of 2μ or less, palladium chloride, and rose nitrate. It is recommended to use a Pd compound such as aluminum6.

This is undesirable because it reduces adhesive strength with the substrate and reduces cost benefits. ' The vehicle used for the active paste is ethyl cellulose, polyvinylpyrrolidone, polyhinylbutyral rub, terpineol, or the like dissolved in a solvent, and the above-mentioned Pd component is mixed with this vehicle to form the active paste.

Although the above-mentioned active paste can provide sufficient adhesive strength, this active paste further contains glass powder of 06 to 6 weight ratio or B1203.

The adhesive strength can be further improved by adding a low melting point oxide (including those that become oxides after firing) such as B203 and PbO. Furthermore, printing accuracy can be improved by adding 1 to 30% by weight of carbon powder to the active paste.

After applying the oil-distributing paste on top and drying it, heat treat it to P.
d) The heat treatment is preferably carried out in the air at a temperature in the range of 400 to 9o゛0''C (1i71(-)) to precipitate the gold-like particles. In both cases, if the Pd component is a Pd compound, it is not formed as stable Pd metal fine particles, which may lead to failure of uniform electroless plating deposition or deterioration of adhesive strength. In addition, if the temperature exceeds this upper limit, uniform precipitation of metal particles cannot be obtained, so a plating film with good electrode function cannot be formed. In the present invention, the Pd metal fine particle layer precipitated by the above heat treatment has an average thickness of 1 μm or less, and has no tingling or conduction.

After forming the Pd metal fine particle layer, a metal film layer 16 is formed thereon by electroless plating.

Usually, this electroless plating uses Ni or Cu electroless plating. Furthermore, in order to improve solderability, this plating film is usually protected with an anti-sugar film.

? Ukai Sho 58-107606 (3) A glaze-based chip resistor is manufactured by the above steps.

Hereinafter, the present invention will be explained based on examples.

A large number of identical patterns (32mm x 16
A ruthenium oxide based glaze resistor paste (f) is applied to the required portions within each pattern of the alumina porcelain base formed with a
After printing, drying at 120''C, and baking at aso'C, a glaze resistive film was formed.

Next, after dividing this substrate along the horizontal grooves, the ends of the resistive film and the electrodes at each end are coated with PdC or 2μ
An active paste containing the following Pd powder in a weight range of 001 to 10% using a vehicle consisting of polyvinylpyrrolidone as a resin component and terpineol as a solvent was applied. After drying this substrate at 120°C for 10 minutes, it was exposed to air for 20°C.
Heat treatment was performed at a temperature of ~1000''C for 30 minutes to deposit a Pa metal fine particle layer. Next, the plating resist was thread-hardened on the glaze resistive film except for the electrode part 1.

This substrate was plated for 10 minutes with an N1-P based non-9B-7 electrolytic plating solution containing nickel sulfate, sodium citrate, and sodium hypophosphite for 10 minutes.
An i-P plating film was deposited to form a plating electrode.

In addition, in the - example, boron hydride was used as the reducing agent, and a film of about 4 μm of N1-B plating was formed. Also,
In the case of electroless Cu plating, plating was performed for 40 minutes with a plating solution containing copper sulfate, EDTA, caustic soda, and formalin to obtain a Cu plating film of about 3 μm. Further, when forming a 5n-Pb layer on the electrode portion, a eutectic solder layer of about 3 μm was deposited by electroplating. This substrate was divided along vertical grooves to create chip resistors.

As a conventional example, the electrode part is a baked electrode of Aq-Pd paste, and one electric Cu plating is applied on top of the baked electrode.
μ, 3μ of eutectic solder plating was used.

For each sample obtained, the deposition Q of electroless plating was determined. In addition, the adhesive strength of the non-dissolved plating was measured by using an alumina porcelain substrate, forming a 6φ plating electrode on the surface of the substrate by the method of the present invention, and soldering it.

As is clear from the explanations and tables on pages 13 and above, the method of the present invention allows Ni, Cu to be easily and precisely deposited at the required locations.
It can form base metal electrodes such as, and has excellent adhesive strength and solderability. Furthermore, the method of the present invention has advantages such as not causing migration of FiAq, and also has great advantages in terms of manufacturing man-hours and cost, so it is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional glaze type chip resistor, and FIG. 2 is a sectional view showing an example of a glaze type chip resistor obtained by the present invention. 11...Heat-resistant insulating substrate) 12...Glaze-based resistive film, 13...Plating resist,
14°, Pd metal fine particle layer, 15,
,,,electroplated film, 16,,,,,,electroplated film. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Scope of Claims] (1) After applying a paste containing Pd component of 002 to 6% by weight to the electrode portion including the ends and each end face of the glaze resistance film provided at required locations on the heat-resistant insulating substrate and drying. ,
A method for manufacturing a chip resistor, which comprises heat-treating in a temperature range of 400 to 900°C, and forming a Ni or Cu plated electrode thereon by electroless plating. (2) A method for manufacturing a chip resistor according to claim (1), characterized in that a heat-resistant insulating substrate whose two surfaces are roughened by physical or chemical treatment is used. (3) Zero glass powder and low melting point oxides in the paste.
The method for manufacturing a chip resistor according to claim 1, characterized in that the content is 6 to 6% by weight. )+41 The method for manufacturing a chip resistor according to claim (1), characterized in that the glaze resistance film is cured before electroless plating. (6) The method for manufacturing a chip resistor according to claim (1), characterized in that after electroless plating, a Sn or Sn-Pb plating film is formed on the electrode portion by electroplating.