JPH0319681B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing a thick film resistor, and particularly to a method for manufacturing a thick film resistor made of silicide particles and non-reducible glass. 2. Description of the Related Art In recent years, the demand for smaller devices and more multifunctional devices has become stronger with each passing year. To meet this demand, high-density mounting of circuit components has become an important technology along with the use of ICs for circuits. For this reason, passive elements such as resistors and capacitors have shifted to thick-film elements for both ease of mounting on substrates and miniaturization. Conventional thick film resistors are generally made by forming electrodes on a sintered porcelain substrate whose main component is alumina by metalizing noble metals consisting of silver (Ag) and palladium (Pd) in air. It was obtained by baking a glazed resistor made of ruthenium oxide (RuO ₂ ) and lead oxide glass in air.
(For example, "Thick film IC technology" edited by Japan Microelectronics Association, published by Kogyo Kenkyukai, pp. 26-34)
However, in the above configuration, since noble metals are used for both the electrodes and the resistor, it is not only expensive, but also nickel (Ni) is used in the electrode part to prevent solder cracking and movement of the silver (Ag). There was a problem that it took time and effort to apply plating such as. Such noble metals, such as copper (Cu), which are inexpensive base metal materials suitable for electrodes, generally cannot be metallized in air, while ruthenium oxide (RuO ₂ )
The glaze resistance material is ruthenium oxide (RuO ₂ ).
It is used because it cannot be formed in a non-oxidizing atmosphere due to the reduction reaction of . In contrast, a silicide-glass thick film resistor has been proposed, which uses a base metal such as copper as an electrode and is fired in a non-oxidizing atmosphere. It is true that this configuration is inexpensive because it uses base metals for both the electrode and the resistor material.
Metals such as Cu have advantages such as easy soldering and resistance to migration. In addition, initial resistance characteristics such as temperature coefficient of resistance (TCR), noise, and short-time overload characteristics are determined by RuO ₂
It is as good as the glaze resistance. Problems to be Solved by the Invention However, although the above-mentioned resistance is initially satisfactory, the change in resistance over time is large, which leaves a great deal of concern in practical use. In particular, when the resistor is left in a high-temperature, high-humidity environment for a long period of time, the area resistance increases mainly on the surface of the resistor, resulting in a change in resistance that is unsuitable for practical use. This is thought to be caused by a chemical reaction between the silicide particles on the surface of the resistor due to moisture and heat, although it has not been made clear. As described above, the conventional silicide-glass glaze resistor has been difficult to put into practical use due to its unstable life span. The present invention solves the above-mentioned problems and provides a method for manufacturing an inexpensive and highly reliable thick film resistor that can be formed in a non-oxidizing atmosphere using a base metal conductor as an electrode. Means for Solving the Problems In order to solve the above problems, the manufacturing method of the present invention includes preparing a mixture of silicide and non-reducible glass in advance.
It includes a process of heat treatment in an oxidizing atmosphere at 500 to 1200°C and then pulverization. Function: Originally, oxides constituting glass have poor wettability with respect to silicides. Therefore, although it is necessary to form an oxide film only on the very surface of the silicide particles, an interaction between the glass and the silicide, which is fired in a non-oxidizing atmosphere, cannot be expected. According to the method of the present invention, the heat treatment slightly oxidizes the silicide surface and melts the glass, covering the silicide particles and integrating the two.
Even when the film is pulverized and fired into a resistive film, the silicide particles are not exposed on the film surface, making it less susceptible to external humidity and improving its moisture resistance. Therefore, an inexpensive and highly reliable thick film resistor that can be formed in a non-oxidizing atmosphere using a base metal conductor as an electrode becomes possible. Example Hereinafter, an example of the method for manufacturing a thick film resistor of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a thick film resistor according to an embodiment of the present invention, in which 10 represents an insulating ceramic substrate, 20 represents an electrode film, and 30 represents a resistive film. Further, FIG. 2 shows a model diagram of a heat-treated powder obtained by the method of the present invention, and FIG. 3 shows a model diagram of a conventional resistor powder, in which 41 and 51 are silicide particles, 42
43 is a glass particle, 43 is a heat-treated fine particle, and 52 is a glass particle. First, powders of silicides such as molybdenum silicide (MoSi ₂ ), tantalum silicide (TaSi ₂ ), magnesium silicide (Mg ₂ Si ₂ ), cobalt silicide (CoSi ₂ ), and nickel silicide (NiSi ₂ ) were prepared. These silicide powders,
95 to 20% by weight of glass frit made of non-reducible oxides such as BaO, B ₂ O ₃ , MgO, CaO, SiO ₂ was added and mixed well. This mixed powder was dry-molded using a metal mold into a bulk shape, and then heat-treated in an oxidizing atmosphere at 500 to 1200°C for a holding time of 10 minutes to 1 hour. The atmosphere at this time was varied by controlling the flow rate of air, N ₂ + air, a mixed gas of N ₂ + a small amount of O ₂ gas, etc. The optimum heat treatment atmosphere varies depending on the softening point of the glass, the type of silicide, and the concentration of silicide. This heat-treated product was pulverized by wet pulverization in a ball mill in xylene to obtain a heat-treated powder. When this heat-treated powder was observed using a SEM, it was found that it had a structure in which silicide particles 41 were confined in glass 42, as shown in FIG. Add the above-mentioned unheated glass frit to this heat-treated powder as needed so that the silicide content is in the range of 6 to 50% by weight, and further add 10% by weight of a thermally decomposable organic binder such as acrylic to terpinenol.
The dissolved vehicle was added and kneaded with a three-stage roll to obtain a resistance paste. On the other hand, alumina purity is 96
An evaluation board was prepared in which an electrode film 20 was formed by metallizing base metal conductors such as copper, cobalt, nickel, and iron at high temperatures in a non-oxidizing atmosphere on an insulating ceramic substrate 10 that was a sintered body of 10%. Screen print the above resistance paste on this evaluation board, dry it at 120℃ for 10 minutes, and then
The resistive film 30 was obtained by firing at ~1100° C. in a non-oxidizing atmosphere of nitrogen or a mixed gas containing nitrogen, several percent hydrogen, and a small amount of water vapor. Various properties of the thick film resistor thus obtained as a resistor were investigated. Table 1 shows the area resistance value (R ₀ ) of the thick film resistor obtained in this example and the conventional thick film resistor, and the resistance temperature relationship between 25°C and 125°C.

[Table] Overload test (OLT) showing number (TCR), noise, and resistance change rate after applying a load of 150 mw/mm ² for 5 seconds
1000 in an atmosphere with a temperature of 70°C and a relative humidity of 95%.
The results of the resistance change rate (ΔR) after being left for a certain period of time are shown. A comparison with the conventional example shown in Table 1 shows that the thick film resistor obtained by the manufacturing method of the present invention has excellent characteristics. Furthermore, from the comparison between the samples in the examples in the same table, it is found that in the manufacturing method of the present invention, it is sufficient that the inorganic component of the resistor is composed of silicide and non-reducible glass, depending on the type of silicide material. It can be seen that the effect does not change significantly, and at the same time, there are no major differences depending on the metal material used for the electrode film. The heat treatment temperature range varies depending on the combination of the oxidation start temperature of the silicide used and the softening temperature of the non-reducing glass, but it is difficult to melt glass at temperatures lower than 500℃, and in some cases it may be difficult to melt glass at temperatures higher than 1200℃. The temperature is preferably in the range of 500 to 1200°C since evaporation of glass components and reaction with the container during heat treatment occur. moreover,
The lower limit of the firing temperature of the resistive film is a temperature at which non-reduced glass flows sufficiently, and the upper limit is a temperature at which no reaction occurs with the electrode material used, and is preferably 800 to 1100°C. Effects of the Invention As described above, in the manufacturing method of the present invention, a mixture of silicide and non-reducing glass is heat-treated in an oxidizing atmosphere at 500 to 1200°C, pulverized, and then printed to form a non-reducing high-temperature glass. By firing with , it is possible to provide an inexpensive and highly reliable thick film resistor that can be formed in a non-oxidizing atmosphere using a base metal conductor as an electrode, and is extremely useful industrially.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a thick film resistor according to an embodiment of the present invention, Figure 2 is a model diagram of a SEM observation of heat-treated powder obtained by the method of the present invention, and Figure 3 is a conventional resistor. It is a model diagram of SEM observation of powder. 10... Insulating ceramic substrate, 20... Electrode film, 3
0...Resistive film, 41...Silicide particles, 42...Glass, 43...Heat-treated powder particles, 51...Silicide particles, 52...Glass particles.

Claims (1)

[Claims] 1. Non-reducible glass together with silicide particles
After going through the steps of melting the silicide particles in an oxidizing atmosphere at a temperature of 1200° C. and pulverizing the molten mixture, a base metal conductor is placed on an insulating ceramic substrate metallized as an electrode. A method for producing a thick film resistor, comprising printing and firing in a non-oxidizing atmosphere at a temperature of 800 to 1100°C. 2. The method for manufacturing a thick film resistor according to claim 1, wherein the silicide particles are one or more of molybdenum silicide, tantalum silicide, magnesium silicide, cobalt silicide, and nickel silicide.