JPH09246007A - Resistance paste and manufacture of resistor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable using general paste thickening resin and reduce the cost, by using copper oxide, nickel oxide, glass fine powder, thickening resin and solvent as main constituent elements. SOLUTION: The main constituent elements of this resistance paste is copper oxide, nickel oxide, glass fine powder, thickening resin and solvent. The resistance paste is spread or printed on an insulating board. After a compound oxide layer of metal is formed by baking, a resistance layer composed of a copper-nickel alloy film can be formed by heat treatment in a reducing atmosphere. When a resistor is manufactured, a resistance layer is formed after electrodes composed of conducting material such as gold, silver and copper are previously formed on the insulating board. In another case, electrodes are formed after the resistance layer is formed. In the case that the electrodes are formed after the resistance layer is formed, the electrodes are formed in a neutral or nonoxidizing atmosphere or in vacuum. Thereby a resistor excellent in the resistance temperature coefficient can be manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance paste widely used in the electronics industry and a method for manufacturing a resistor using the same.

[0002]

2. Description of the Related Art As a resistance paste for a conventional resistor,
A so-called thick film paste using a silver-palladium alloy has been mainly used, but a thick film paste using this silver-palladium alloy tends to have a large temperature coefficient of resistance, and copper and nickel fine powders are used as an improvement measure. A resistance paste mixed with glass powder is disclosed in JP-A-2-308501.
Japanese Patent Publication No. 5037670 and the like.

[0003]

However, the resistance paste mainly composed of copper-nickel alloy powder and glass is used in the paste because it is fired in nitrogen or in a weak reducing atmosphere in order to prevent oxidation of the main constituent metal powder. There is a problem that it is difficult to freely control the flow characteristics of the paste because the thickening resin that can be used is limited.

The present invention solves the above-mentioned conventional problems. A general paste thickening resin can be used, can be manufactured at low cost, and has excellent reproducibility of resistance temperature coefficient. It is an object of the present invention to provide a method for manufacturing a resistor.

[0005]

In order to achieve the above object, the present invention uses a resistance paste containing copper oxide, nickel oxide, glass fine powder, a thickening resin and a solvent as main components. is there.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is
The main constituents are copper oxide, nickel oxide, glass fine powder, a thickening resin and a solvent.

The invention according to claim 2 further comprises the step of forming an electrode on the insulating substrate, and copper oxide which is superposed on the electrode.
A step of applying a resistance paste mainly composed of nickel oxide, glass fine powder, a thickening resin and a solvent, and firing the resistance paste to form a copper and nickel composite oxide layer on an insulating substrate. And a step of reducing the composite oxide layer of copper and nickel formed on the insulating substrate to form a resistor layer made of an alloy of copper and nickel.

According to a third aspect of the present invention, a step of applying a resistance paste containing copper oxide, nickel oxide, glass fine powder, a thickening resin and a solvent as main constituents to the insulating substrate, and the resistance. Baking the paste to form a composite oxide layer of copper and nickel on the insulating substrate,
Forming a resistor layer made of an alloy of copper and nickel by reducing a composite oxide layer of copper and nickel formed on the insulating substrate; and forming a resistor layer made of an alloy of copper and nickel on the resistor layer. And a step of forming an electrode.

An embodiment of the present invention will be described below. The copper oxide and the nickel oxide used in the resistance paste according to the present invention are pulverized with a commercially available powder using a pot mill, a jet mill, a stone mill, etc. to adjust the particle size distribution suitable for the paste.

The glass powder that can be used in the above resistance paste is heated in a reducing atmosphere when the resistance film is formed, so it is desirable that the composition be such that it is not easily reduced. Specifically, it is a lead borosilicate glass having a relatively low lead content, or a zinc borate glass.

Thickening resins that can be used in the above resistance paste include ethyl cellulose, hydroxyethyl cellulose, cyanoethyl cellulose, acetyl cellulose,
Cellulose derivatives such as nitrocellulose, butyral resins, polyvinyl alcohol, phenoxy resins, acrylic ester copolymers, phenol resins, epoxy resins and other general paint resins can be used.

The solvent for the resistance paste may be any solvent that can dissolve the thickening resin, but when used for screen printing, one having a relatively slow evaporation rate is preferable. Examples of slow evaporation rates include high boiling point ketones such as isophorone, butyl carbitol, diethylene glycol derivatives such as butyl carbitol acetate, ethylene glycol derivatives such as ethyl cellsolve, cellosolve acetate, high boiling point alcohols such as benzyl alcohol and terpineol. is there.

In addition to the above main constituents, various additives for coating materials can be added to the resistance paste according to the present invention for the purpose of improving leveling property and defoaming property.

The resistance paste according to the present invention is applied or printed on an insulating substrate and then fired to form a composite oxide layer of the above metal, and then heated in a reducing atmosphere to form a copper-nickel alloy film. Can be formed.

In manufacturing the resistor according to the present invention, an electrode made of a conductive material such as gold, silver or copper is formed on the insulating substrate in advance, and then a resistor layer is formed by the above manufacturing method. Alternatively, on the contrary, the electrodes may be formed after forming the resistor layer on the insulating substrate. However, since the copper-nickel alloy film is oxidized by heating at high temperature in air, when forming the electrode after forming the resistor layer, it is preferable to form the electrode in a neutral or non-oxidizing atmosphere or in vacuum. The electrodes can be formed by a method such as printing or applying an electrode paste, sputtering of a conductive material, vapor deposition, or thermal spraying.

As another electrode forming method, it is possible to form an electrode by plating after laminating a conductive resin on the resistor layer by means such as printing or coating.

[0017]

Embodiments of the present invention will be described below.

(Example 1) Commercially available cuprous oxide powder (reagent first grade) 430 g and nickel oxide powder (reagent first grade) 3
36 g was put into a nylon pot mill, zirconia balls and alcohol were put therein, and the mixture was pulverized and dried to obtain a mixed powder of the above oxide.

Glass fine powder (glass composition: 9.9% silica, 35.6% zinc oxide, 44.3% boron oxide, 6.7% sodium oxide, 1.7% lithium oxide, alumina) was added to 95 g of the above mixed powder. 1.5%) 5g, ethyl cellulose 10% solution (solvent: butyl carbitol) 5
After mixing with 0 g, it was kneaded with a ceramic three-roll mill to produce a resistance paste. The resistance paste obtained here had a fluidity suitable for screen printing.

The above resistance paste was screen-printed on an alumina substrate, dried and baked at 650 ° C. to form a sintered body of a mixed powder of copper oxide and nickel oxide on the alumina substrate.

Subsequently, the alumina substrate on which the mixed powder sintered body was formed was heated at 400 ° C. in nitrogen gas containing 5% hydrogen to form a resistor layer made of a copper-nickel alloy. The resistance layer obtained here has an area resistance value of 200 mΩ /
□, temperature coefficient of resistance between 25 ℃ and 125 ℃ is 145p
It showed pm and could be used as a resistor for low resistance.

After forming a resist film mainly composed of epoxy resin on the central portion of the resistor layer formed on the alumina substrate, a copper terminal is formed on the exposed portion of the resistor layer by electroplating. The resistor could be manufactured.

(Example 2) A resistor paste was manufactured by using a commercially available fine powder of lead borosilicate glass at 850 ° C as glass in Example 1. This paste was screen-printed on each individual piece on the alumina substrate in which break grooves were previously provided, and baked at 850 ° C. to form an oxide layer on each individual piece of the alumina substrate. As a result of X-ray diffraction, it was confirmed that the oxide layer was a copper-nickel composite oxide layer.

The alumina substrate on which the composite oxide layer was formed was heat-treated at 400 ° C. in nitrogen containing 5% hydrogen to form a resistor layer made of a copper-nickel alloy on the alumina substrate. The alumina substrate provided with the resistor layer is divided into strips along the break groove, and copper paste is applied to the two opposite long sides of the strip substrate and baked at 900 ° C. in nitrogen to form end face electrodes. Formed. Subsequently, the strip-shaped substrate was divided along the break groove into individual pieces, and nickel and solder were plated on the copper paste by a partial plating method to manufacture a chip resistor having a resistance value of 100 mΩ and a resistance temperature coefficient of 50 ppm.

Example 3 In Example 2, after forming a resistor layer made of a copper-nickel alloy, an epoxy resin-based overcoat layer was screen-printed on a necessary portion of the resistor layer, and 180 After curing at ℃, the alumina substrate was divided into strips along the break grooves. The epoxy resin-dispersed silver paste is applied to the two opposite long sides of the strip-shaped substrate and cured at 180 ° C., and then nickel and solder are plated on the resin-dispersed copper paste by barrel plating to produce resistance. Value 100mΩ, resistance temperature coefficient 50p
A pm chip resistor was manufactured. The chip resistor obtained here had an electrode strength equivalent to that of a normal chip resistor.

Comparative Example 1 The same lead borosilicate glass fine powder and ethyl cellulose solution as in Example 2 were added to commercially available copper and nickel fine powders, and a resistance paste was produced using a three-roll mill. This resistance paste was screen-printed on an alumina substrate having break grooves in the same manner as in Example 2, and baked at 850 ° C. in a nitrogen atmosphere. The resistor layer obtained here was grayish black in which carbon remained, and did not show stable resistance characteristics.

Comparative Example 2 An acrylic resin-based thickening resin was used in place of ethyl cellulose in Comparative Example 1. In this comparative example, in order to exhibit the same flow characteristics as in Example 2, it was necessary to increase the amount of resin four times. Furthermore, although a metallic glossy film was obtained on the generated resistor layer, scattering of the resistor layer outside the screen-printed area,
The pattern collapsed.

[0028]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a very inexpensive material such as copper oxide or nickel oxide is used as a starting material, and the conventional printing method and firing method are used.
A resistor having an excellent temperature coefficient of resistance can be manufactured.
Further, since it is fired in air, a wide range of thickening resins can be selected, and a resistance paste suitable for a printing method can be easily produced, which has a great industrial effect.

Claims (3)

[Claims] 1. A resistance paste comprising copper oxide, nickel oxide, glass fine powder, a thickening resin and a solvent as main components. 2. A step of forming an electrode on an insulating substrate, and a resistance paste mainly composed of copper oxide, nickel oxide, glass fine powder and a thickening resin and a solvent, which is superposed on the electrode. A step of firing the resistance paste to form a copper and nickel complex oxide layer on an insulating substrate; and reducing the copper and nickel complex oxide layer formed on the insulating substrate. And a step of forming a resistor layer made of an alloy of copper and nickel. 3. A step of applying a resistance paste mainly composed of copper oxide, nickel oxide, glass fine powder and a thickening resin and a solvent to an insulating substrate, and baking the resistance paste to form copper and nickel. Forming a complex oxide layer on the insulating substrate, and reducing the complex oxide layer of copper and nickel formed on the insulating substrate to form a resistor layer made of an alloy of copper and nickel. A method of manufacturing a resistor, comprising: a step of forming an electrode on a resistor layer made of the alloy of copper and nickel.