JPH0352202A - Method of manufacturing thick film resistors - Google Patents

Abstract

PURPOSE:To make a resistor small in size and to lower the cost thereof by a method wherein a resistance paste is applied on a ceramic base, dried and baked, and thereafter an electrode paste is applied to a prescribed position, dried and then baked at a lower temperature than that for baking the resistance paste. CONSTITUTION:First a resistance paste is applied on a ceramic base, dried and baked, and subsequently an electrode paste is applied to a prescribed position, dried and then baked at a lower temperature than that for baking the resistance paste. Any resistance paste may be used herein on condition that it is a resistance paste, such as that of RuO2 or Pb2Ru2O6, which can be baked at a temperature of 700 to 1000 deg.C. It is aimed to prevent a sharp change in the performance of a resistance film formed earlier that the electrode paste is baked at the temperature lower than that for baking the resistance paste, and an appropriate degree of the temperature differs according to the kind of resistance paste. Therefore, it may be determined experimentally within the range of 500 to 700 deg.C. According to this constitution, a small-sized thick-film resistor can be obtained inexpensively without deterioration of the performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method suitable for manufacturing ultra-small thick film resistors.

[Conventional technology]

Thick film resistors are usually made by first forming the necessary electrodes on a ceramic substrate by applying electrode paste, drying, and baking, then applying the required resistance paste between the electrodes, drying,
It is manufactured by firing. The reason why the resistive paste is baked after the electrode paste is that the characteristics of the resistive film will change significantly if the resistive paste is baked twice at approximately the same temperature.

Incidentally, in recent years, electronic components have become more densely packed, and thick film resistors are also required to be smaller. In addition, there is a demand for cost reduction, and Ag-P used as an electrode paste.
Even in d-based pastes, there is a trend toward low-priced products with a reduced content of expensive Pd, and the Pd content has no choice but to further decrease.

[Problem to be solved by the invention]

However, as the Pd content in the Ag--Pd electrode paste used decreases, the Ag in the electrode becomes more likely to diffuse into the resistor, and this diffusion causes changes in the performance of the resistor. The effect of diffusion becomes more negligible as the resistor becomes smaller. In other words, it can be safely assumed that miniaturization and cost reduction of thick film resistors have reached their limits as long as conventional resistor manufacturing techniques are used.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method that eliminates the drawbacks of the prior art described above and allows manufacturing smaller thick film resistors at low cost without deteriorating performance.

[Means to solve the problem]

In order to achieve the above object, the method of the present invention first applies a resistance paste on a ceramic substrate, dries and fires it, then applies an electrode paste at a predetermined position, and after drying, from the time of firing the resistance paste. It is also characterized by being fired at a low temperature.

The resistance paste to which the method of the present invention can be applied is not particularly limited, and includes Rung type, Pb. RuzO. 700 series etc.
Any resistance paste that can be fired at ~1000°C may be used. Such a resistance paste is first applied onto a substrate by screen printing or the like, the solvent in the paste is evaporated to dry the coating film, and the paste is fired under predetermined conditions. Next, an electrode paste is applied to a predetermined position of the fired resistive film to serve as an electrode, and after drying, it is fired at a temperature lower than that of the resistive paste.

[For production]

The reason why the electrode paste is fired at a lower temperature than when firing the resistance paste is to avoid significantly changing the performance of the previously formed resistive film. The appropriate temperature varies depending on the type of resistor paste, so it may be determined experimentally within the range of 500 to 700°C.

As the electrode paste, materials containing Ag as the main component, such as Ag-Pd type and Ag-Pt type, are preferred from the viewpoint of ease of soldering. These electrode materials are 700 to 900
The type that is fired at ℃ is common, but as mentioned above, in order to fire at a lower temperature, the softening point of the glass used in the paste is lowered and the glass content is slightly increased, etc. It is necessary to select a suitable combination. Various types of such electrode pastes for low-temperature firing are commercially available, and can be obtained as appropriate in the same way as resistance pastes.

As described above, in the method of the present invention, since the sintering temperature of the electrode paste is lowered, a certain amount of conductive diffusion into the resistive film is reduced. In particular, in order to ensure the stability of the resistive film, high-temperature firing type resistance pastes are increasingly being used, but according to conventional methods, the higher the resistor paste is fired, the more it diffuses from the previously formed electrodes. Therefore, when using such a resistor paste, the method of the present invention is highly effective.

〔Example〕

Ag powder 57.0, Pd powder 0. 5, glass powder I2.5,
30.0% organic vehicle, each weight % electrode paste;
Rub. Resistance paste of 16.0% powder, 53.0% glass powder, 31.0% organic vehicle, 100Ω/hole each by weight (
This is called A resistance paste) or PbzRuzOi
Powder 26. O, glass powder 45.5, organic vehicle 28.
5. Resistors were prototyped in combination with resistance pastes of 100 kΩ/mouth (referred to as B resistance pastes) of various weight %. Glass powder composition or resistor is PbO 70, Si
Od9, ^lzos9, BzOi 2, each weight%, for electrodes Pb074, SiOzl8, aLOz 5,
For each wt% of CaO3, a 15 wt% terpineol solution of ethylcellulose was used as the organic vehicle.

First, apply resistor paste to a length of 1. 0mm
, width 0. A 5 mm pattern was printed, and after drying, it was fired in a belt-type firing furnace with a temperature profile of a peak temperature of 850''C, a peak time of 10 minutes, and a total firing time of 60 minutes.

Next, apply electrode paste to both ends of this resistive film so that the distance between the electrodes is 0.
．． 5mm, and the peak temperature was 600mm.
"It was fired in a firing furnace with a C1 peak time of 5 minutes and a total firing time of 30 minutes. The resistive film was coated with glass, and the sheet resistance value, temperature coefficient of resistance (TCP), and load life (70
°C, 1.5Hon・0.5Hoff, rated power 1/
16W), humidity load life (40℃.95%RH, 1
．． 5 H on ・0.5 H off, rated power 1
/16W) was measured. In addition, for comparison, Ag powder 60.0, Pd powder 5.0, glass powder 15.0 (combined or Pb0 70. O, Si
Oz 20. 0, Bz (h 10. O, each weight%)
, an organic vehicle of 20.0% by weight, and an electrode paste of each weight %, and a distance between electrodes of 0.0% was first applied to an alumina substrate according to the conventional example.
Print a 5 aa electrode pattern, burn it at 850″C, and connect the resistor bases A and B to a length of 1.0 m between the electrodes.
m, width 0. Print with 5 mm pattern and heat at 850°C.
The same measurements as above were performed.

The results are summarized in Table 1.

Table 1 The results in Table 1 show that the method of the present invention shows the original performance of the resistor, while the conventional method shows that the performance is significantly reduced, and the method of the present invention shows that it is not affected by the electrode material. It turns out that resistors can be manufactured.

〔Effect of the invention〕

The present invention provides the prospect of further miniaturization and cost reduction of resistors.

Claims (1)

[Claims] When manufacturing a thick film resistor by forming a resistive coating and an electrode on a ceramic substrate, first a resistive paste is applied on the ceramic substrate, dried and fired, and then an electrode paste is applied at a predetermined position. A method for manufacturing a thick film resistor, comprising firing the resistor paste at a lower temperature than when firing the resistor paste after drying.