JPS6250041B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistance composition used for fixed resistors, variable resistors, resistors for hybrid integrated circuits, etc., and a method for manufacturing the same.

Conventionally, resistor compositions using silver (Ag) and noble metals such as palladium (Pd) or ruthenium dioxide (RuO ₂ ) have been used in precision fixed resistors and resistors for hybrid integrated circuits. A resistor using this composition is generally known as a highly reliable resistor that has excellent heat resistance and power resistance because it is made of noble metals, their oxides, and glass. However, this resistance composition
A major drawback is that it is very expensive because it uses precious metals such as Ag, Pd, or ruthenium, making it difficult to use in inexpensive consumer resistors. On the other hand, resistor compositions that do not use noble metals include those that use indium oxide, tungsten carbide, etc. and glass frit;
It has the disadvantage that it must be fired in a reducing atmosphere (1250°C), which significantly increases the firing cost. There are two major ways to try to improve this drawback. One of these is (a) a method to reduce firing costs by firing in air using cadmium oxide, silicide, etc. and glass frit, and the other is (b) low temperature (600 to 900℃). This is a means of reducing firing costs by firing in a reducing atmosphere.

The major problem with (a) firing in air is that electrode materials that do not use noble metals have not yet been put into practical use. The problem with (b) firing in a low-temperature reducing atmosphere is that resistance compositions containing metal powders (e.g. copper, copper-nickel alloys), glass formations, and organic binders have narrow temperature range conditions during the process of burning the organic binder. (For example, in the case of a copper-nickel alloy, the resistance value changes from 10 ⁸ Ω to 10 ⁰ at about 10°C.) Mass production is difficult.

An object of the present invention is to provide a resistive composition that solves this problem and can be fired in a low-temperature reducing atmosphere.

According to the present invention, electrolytic copper powder is mixed with various metal oxides, heat-treated in advance at a temperature of 600 to 900°C in a reducing atmosphere, cooled, and then pulverized again. A resistance composition and a method for producing the same are obtained.

Hereinafter, the resistance composition of the present invention will be explained in detail based on Examples.

Example 1 The conductive powder was prepared by immersing 65% by weight of electrolytic copper powder and 35% by weight of talc in ethyl alcohol and mixing them in a pot for 24 hours using an alumina ball mill.The overdried powder was then pressed at a pressure of 3 tons. /cm ² and press-molded into pellets with a diameter of 5 mm and a thickness of 3 mm. The pellets were placed on an alumina boat, heated in a diffusion furnace flushed with argon gas at a temperature of 800°C for 2 hours, and then slowly cooled. The heat-treated pellets are roughly crushed by crushing them with a hammer, then finely crushed with a grinder, placed in a pot with ethyl alcohol, mixed and crushed for 24 hours using an alumina ball mill, and made into a fine powder. Conductive fine powder was produced. Glass forming powder is lead oxide: 60
Weight%, boric acid: 20% by weight, silicon oxide: 10% by weight, aluminum oxide: 5% by weight, zinc oxide: 5
Mix the weight% in a mortar and put it in an alumina boat.
It was heated to a temperature of 1200°C to melt it, and then this melt was dropped into water to obtain microparticles. Next, the mixture was placed in a pot with water and pulverized using a ball mill for 72 hours to produce a powdered glass product. Note that the composition ratio of the glass forming powder is not necessarily limited to the above composition ratio. Next, conductive fine powder and glass forming powder were mixed at a ratio of 20:80% by weight, and in order to provide printability, β-terpinol and ethyl cellulose were mixed as an organic binder at a ratio of 9:1 (weight ratio). The mixture was added at a ratio of 40% by weight to produce a paste-like resistance composition. This paste-like resistive composition was screen printed onto an alumina porcelain substrate using a 200 mesh screen, dried at a temperature of 150°C for 10 minutes, and then passed through a tunnel furnace in an air atmosphere heated to a maximum temperature of 300°C. to burn the ethyl cellulose.

Next, this substrate was baked in a tunnel furnace having a holding area at a maximum temperature of 850° C. for 10 minutes in an atmosphere in which argon gas was flowed to produce a metal oxide resistor. On the other hand, for the electrodes connected to the resistor, before printing and firing the resistor, a paste containing copper powder and glass forming powder was screen printed, dried, and then fired in a tunnel furnace in which argon gas was flowed. The film thickness of this resistor after firing is approximately 30 μm.
It was hot. The sheet resistance value at room temperature was 1.1 kΩ. The temperature coefficient of resistance measured between 25°C and 125°C was +150PPm/°C. The load life characteristics are 25mw/ ^mm2 load power at an ambient temperature of 70℃.
After repeating a cycle of applying load power for 1.5 hours and removing only the load power for 0.5 hours for 1000 hours, the rate of change in resistance value was found to be within ±1%.

Example 2 A product was manufactured under the same conditions as in Example 1 using the same process as in Example 1, using 55% by weight of electrolytic copper powder and 45% by weight of zinc oxide as conductive fine powder. The sheet resistance value at room temperature was 23 kΩ. The temperature coefficient of resistance measured between 25℃ and 125℃ is -110PPm/
It was warm at ℃. Load life characteristics are 25m at an ambient temperature of 70℃
After repeating a cycle in which a load power of w/mm ² was applied for 1.5 hours and only the load power was removed for 0.5 hours for 1000 hours, the rate of change in resistance value was within ±0.1%.

Example 3 Electrolytic copper powder: 56% by weight, silicon oxide: 25% by weight, and boron dioxide: 8% by weight as conductive fine powders
and phosphorus pentoxide: 4% by weight, tin oxide: 2% by weight, potassium oxide: 1% by weight, and magnesium oxide: 4%.
Made using the same process and under similar conditions as Example 1 using weight %. The sheet resistance value at room temperature was 150 kΩ.

The temperature coefficient of resistance measured between 25°C and 125°C was -185PPm/°C. The load life characteristics are as follows: After 1000 hours of repeating a cycle in which a load power of 25 mw/ ^mm2 is applied for 1.5 hours and only the load power is removed for 0.5 hours at an ambient temperature of 70℃, the rate of change in resistance is ±
The result was within 0.3%.

As is clear from the examples above, the resistor using the resistance composition of the present invention has extremely excellent resistance properties such as temperature coefficient of resistance and load life characteristics.
Moreover, a resistor composition having many characteristics such as being able to be fired at a low temperature and being much cheaper than noble metal-based resistor compositions can be obtained.

Therefore, it can be used not only for resistors and resistance circuit networks for hybrid integrated circuits, but also for various resistors and variable resistors for electric power, precision, and general use, and has a wide range of uses.

Claims (1)

[Scope of Claims] 1. A resistance composition comprising a mixture of electrolytic copper powder and a metal oxide, and a finely powdered conductive powder mixed with a glass-forming powder. 2. A step of mixing electrolytic copper powder and a metal oxide, subjecting it to high temperature treatment in a reducing atmosphere, cooling it and then mechanically crushing it into a fine powder, and a step of mixing a glass forming material into the fine powder. A method for producing a resistive composition, characterized in that: 3. The resistance composition according to claim 1, wherein the metal oxide comprises talc. 4. The resistance composition according to claim 1, wherein the metal oxide comprises zinc oxide. 5. Claim 5, characterized in that the metal oxide contains silicon oxide, boron dioxide, phosphorus pentoxide, and an oxide of any one or more of tin oxide, aluminum oxide, potassium oxide, and sodium oxide. The resistance composition according to item 1.