JPH0654726B2 - Thick film resistor forming composition - Google Patents

Description

The present invention relates to a thick film resistor forming composition for forming a thick film resistor on a ceramic substrate.

[Conventional technology]

A glass frit with a softening point of 400 to 700 ° C is mixed with conductive powder so that the required resistance value is obtained, and the paste is dispersed in an organic vehicle. A thick film resistor as an electronic circuit component is formed on a substrate by applying it in a shape and baking it at 600 to 900 ° C.

To improve stability of resistance value by using RuO ₂ or Pyrochlore Pb ₂ Ru ₂ O ₆ to ₇ , Bi ₂ Ru ₂ O ₆ to ₇ other than Ag and Pd as the conductive powder. Is also known.

In the manufacturing process of a chip resistor or the like using this thick film resistor, usually, after adjusting the resistance value of the thick film resistor, a reheating process of about 600 ° C. is performed for the purpose of glass coating or the like.
In consideration of the change in the resistance value in this reheating step, the resistance value called trimming is adjusted before that. If there is a large change in the resistance value in this step, it becomes difficult to keep the final resistance value within the expected range, which is a major cause of deterioration in yield.

[Problems to be Solved by the Invention]

The present invention has a small change rate of the resistance value in this reheating step,
Therefore, it is an object of the present invention to provide a composition for forming a thick film resistor, which mainly has a low resistance value and can obtain a thick film resistor with a good yield.

[Means for Solving the Problems]

The present invention relates to a glass powder having a composition containing 35 to 70% by weight of PbO and 15 to 40% by weight of SiO ₂ , 10 to 50% by weight, RuO ₂ , Pb ₂ Ru ₂ O ₆
~ ₇ , powder of at least one of Bi ₂ Ru ₂ O ₆ ~ ₇ 5-40
Wt% organic vehicle 20-40 wt%, B ₂ O ₃ powder 0.2 to 5.
A thick film resistor-forming composition containing these in an amount of 0% by weight, and 10 to 50% by weight of glass powder having a composition containing 35 to 70% by weight of PbO and 15 to 40% by weight of SiO ₂ , and RuO ₂ . Thick film resistor containing at least 5 wt% and 20 to 60 wt% with one or both of Ag and Pd, 20 to 40 wt% organic vehicle, and 0.2 to 5.0 wt% B ₂ O ₃ powder. The forming composition is a means for solving the problems.

Solid powder is mixed with vehicle to form a paste, 15
Since it is applied to the substrate through a mesh screen, it is used as a powder having an average particle size of 10 μm or less, preferably 5 μm or less so that the paste can smoothly pass through the screen.

As the organic vehicle, a solvent obtained by dissolving ethyl cellulose, a methacrylate resin, or the like in a solvent such as terpineol, butyl carbitol acetate, or toluene is used as in the conventional case.

The above glass _{powder, RuO 2, Pb 2 Ru 2} O 6 ~ 7, Bi 2 Ru 2 O 6 ~ 7,
In addition to Ag and Pd powders, B ₂ O ₃ powders, and organic vehicles, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , CuO, and Nb, which have been conventionally used to reduce the TCR (temperature coefficient of resistance) ₂ O ₃ , Sb ₂ O ₃ , TiO ₂
Can be added within 5% by weight.

As the above glass, PbO, ZnO which is usually blended as a glass component in addition to SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , CaO, BaO,
At least one of K ₂ O, Na ₂ O, ZnO and TiO ₂ can be added in an amount of 3 to 35% by weight in order to adjust the softening point, the coefficient of thermal expansion and the like.

[Action]

In the glass composition of the present invention, the content of PbO is 70
The reason why the amount is up to 70% by weight is that if the PbO content exceeds 70% by weight, when the paste applied to the substrate is fired to form a film, the softening at the highest firing temperature becomes remarkable and the pattern shape collapses. . If the PbO content is less than 35% by weight or the SiO ₂ content exceeds 40% by weight, on the contrary, the softening during firing becomes insufficient and the fired coating becomes porous and weak. If SiO ₂ is less than 15% by weight, it becomes difficult to vitrify.

Based on the above, PbO 35 to 70 wt% and SiO ₂ 15 to 40 wt% were set.

If the content of the glass powder exceeds 50% by weight, the resistance value becomes too high, and if it is less than 10% by weight, the adhesive strength of the coating film to the substrate decreases, so the content is made 10 to 50% by weight.

When the RuO ₂ , Pb ₂ O ₆ to ₇ , Bi ₂ Ru ₂ O ₆ to ₇ powder exceeds 40% by weight, the coating after firing becomes extremely porous and the coating strength becomes weak and the reliability decreases, If it is less than 5% by weight, the resistance value becomes too high and the environmental stability such as 150 ° C constant temperature service life deteriorates, and the fluctuation of the resistance value becomes large.
The addition range of O _{2 and the} like is set to a range of 5 to 40% by weight. When used in combination with Ag or Pd in RuO ₂ as the conductive component, RuO ₂ for the reasons mentioned above is required to be at least 5% by weight, RuO ₂ and Ag
If the total of Pd and Pd is less than 20% by weight, the resistance value becomes too high, and if it exceeds 60% by weight, the resistance value becomes too low to be a resistor.

The organic vehicle is indispensable for printing this composition in the form of ink, but if it is less than 20% by weight, it becomes difficult to make it into an ink, and if it exceeds 40% by weight, it is generally used now. The film becomes too thin under printing conditions,
Since the resistance value will fluctuate greatly, the compounding ratio of the organic vehicle should be 20-40% by weight.

B ₂ O ₃ is added to stabilize the resistance against reheating which is the object of the present invention, and is dispersed in the glass to cause a phase separation in the glass, thereby stabilizing the glass phase. , It may be possible to reduce the change in resistance value due to reheating, but if the addition amount is less than 0.2% by weight, there is no effect.
Even if added in excess of 5% by weight, no further improvement in effect was observed, so the range was set to 0.2 to 5.0% by weight.

〔Example〕

RuO ₂ , Pb ₂ Ru ₂ O ₆ to ₇ , Bi ₂ Ru ₂ O ₆ to ₇ , MnO ₂ and Pd powder having an average particle size of 0.1 μm or less, and Ag powder having an average particle size of 0.1 μm or less.
As the glass powder, 1.2 μm having a composition shown in Table 1 and having an average particle size of 1.5 to 3 μm, and B ₂ O ₃ which passed through a 200 mesh sieve were used.

A terpineol solution containing 10% by weight of ethyl cellulose was added to these inorganic powders and kneaded with a three-roll mill to prepare low-resistor pastes having the compositions shown in Table 2.

Conductive paste consisting of Pd 5 wt% Ag paste was applied by screen printing on a 96% pure alumina substrate, the solvent was dried in a belt furnace with a peak temperature of 150 ° C, and then a peak temperature of 850 ° C for 9 minutes. An electrode is formed by firing through a belt furnace having a temperature distribution.

The above paste was printed so as to bridge the electrodes, and dried and fired in the same manner as the electrodes to form a resistor film. The size of the resistor film is 1 mm square.

20 resistors were prepared per composition, and the initial resistance value was measured with a digital multimeter immediately after firing. This average value is called the sheet resistance value (Ω / □). The black glass paste was printed and dried on this, and this time, the glass was baked through a belt baking furnace having a trapezoidal temperature distribution with a peak of 600 ° C. for 5 minutes. The resistance value after firing was measured, and the resistance value change rate (ΔR%) of the resistance value after firing with respect to the initial resistance value was obtained.

The results are shown in Table 2.

Looking at Table 2, as a component in any of the ABC of glass
B ₂ O ₃ is included, but separately from B ₂ O ₃ of 0.2 to 5 and glass.
It can be seen that the ΔR% is improved in each of the samples added with 0% by weight.

〔The invention's effect〕

According to the present invention, it is possible to provide a composition capable of forming a resistance coating capable of reducing the change in resistance value caused by reheating again as compared with the conventional case.

Claims (2)

[Claims] 1. A glass powder having a composition containing 35 to 70% by weight of PbO and 15 to 40% by weight of SiO ₂ , 10 to 50% by weight, RuO ₂ , and Pb ₂ Ru _{2.
O 6 ~ 7, Bi 2 Ru} 2 O 6 ~ 7 or at least one powder 5 of
40 wt% organic vehicle 20-40 wt%, B ₂ O ₃ powder 0.2
A thick film resistor-forming composition containing these in an amount of 5.0% by weight. 2. Glass powder having a composition containing 35 to 70% by weight of PbO, 15 to 40% by weight of SiO ₂ , 10 to 50% by weight of RuO _2, and at least 5% by weight of RuO _2, and one or both of Ag and Pd. 20 ~ 60
Wt% organic vehicle 20-40 wt%, B ₂ O ₃ powder 0.2 to 5.
A composition for forming a thick film resistor containing these in an amount of 0% by weight.