JPH0584680B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a low-temperature fired ceramic circuit board, and particularly to a low-temperature fired ceramic circuit board whose resistance can be easily designed. (Prior art and its problems) In general, the so-called terminal effect, in which specific resistance varies depending on the length and width of the resistor, is difficult to design if it is large, so the terminal effect is used in the field of thick-film hybrid ceramic substrates. An important issue is how to reduce and stabilize this amount. Conventionally, this terminal effect is reduced and stabilized by changing the composition of the resistor paste in high-temperature fired ceramic substrates, but this method is difficult to change at low temperatures where it is difficult to freely change the composition of the resistor paste. It cannot be applied to fired ceramic substrates. For this reason, in the case of low-temperature fired ceramic substrates, conventionally, in order to design resistors having different resistance values using one sheet resistor paste, the length and width of the resistor were adjusted. However, when using a silver (Ag)-based conductor as an electrode,
Resistors with a length of 1 mm or less are not stable because they are affected by the electrodes. However, in order to increase the density of the pattern, the resistor cannot be made too large, and the smaller it is, the more desirable it is. Therefore, in order to satisfy these two contradictory conditions when designing a resistor, the design range of conventional resistors is actually limited to about 30 to 50% of the sheet resistance. (Object of the Invention) An object of the present invention is to provide a low-temperature fired ceramic circuit board which eliminates the above-mentioned problems, has a small terminal effect, and allows easy design of a stable resistor. (Means for Solving the Problems) The present invention is a low-temperature-sintered ceramic made of alumina and a low-melting glass that uses a metal mainly composed of silver or silver-palladium as a conductor and RuO ₂ -glass as a resistor. In the circuit board, a lower conductor layer is arranged below the resistor layer via an insulating layer, corresponding to the position of the resistor layer, and the length L of the lower conductor layer and the effective length l of the resistor layer are arranged. , and the width W of the lower conductor layer and the width w of the resistor layer satisfy the following relational expressions, L≧l, W≧w, and the distance between the resistor layer and the lower conductor layer is
By setting the thickness to 100 μm or less, a low-temperature fired ceramic circuit board with small terminal effect and stability can be obtained. (Example) The present invention will be described below along with a conventional example as a comparative example. FIG. 1a is a longitudinal sectional view of a low-temperature fired ceramic circuit board of the present invention, and FIG. 1b is an enlarged plan view of FIG. 1a. 1 is the substrate (tape), 2, 2' is the substrate 1
an insulating layer laminated thereon, 3 a second conductor layer provided (printed) between the substrate 1 and the insulating layer 2;
4 and 4' are first conductor layers provided (printed) between the insulating layers 2 and 2'; 5 is a resistor layer provided by printing between the first conductor layers 4 and 4'; body layer 5
is arranged so as to be located above the second conductor layer 3. Here, if the width and length of the lower second conductor layer 3 are W and L, respectively, and the width and effective length of the resistor layer 5 are w and l, respectively, then L≧l and W≧w satisfy the relationship. In the illustrated example, the distance between the resistor layer 5 and the second conductor layer 3 was 40 μm. The low temperature ceramic circuit board of the present invention shown in FIGS. 1a and 1b may be fired using commonly known integral firing techniques or separate firing techniques. In the case of simultaneous firing, the second conductive layer 3 is printed on the substrate 1, then the insulating layer 2 is printed, and then the first
By printing the conductors 4, 4', then printing the resistor layer 5 so as to cover between the conductors 4, 4', and printing the insulating layer 2' on top of it, and then integrally firing it. It is formed. On the other hand, in the case of individual firing, the second conductor 3 is printed on the fired substrate 1, and after firing, an insulating layer is further printed and fired, and then printing and firing are repeated in the same manner. The compositions of the tape (substrate), insulating layer, and resistor of the low-temperature fired ceramic circuit board shown in FIG. 1 were as shown in Table 1.

[Table] Also, as a conductor material, Ag for the first conductor layer:
80, Pd: 20 (wt%), and Ag: 100% conductor was used for the second conductor layer. Table 2 shows the resistance value measurement results of the low-temperature fired ceramic circuit boards of the present invention shown in Figures 1a and b and the conventional low-temperature fired ceramic circuit boards shown in Figure 2 held and fired at 900°C for 20 minutes. It shows. Furthermore, the two columns on the right side of Table 2 show the rate of change in sheet resistance when the sheet resistance of a resistor layer with a length of 4 mm is used as a reference. The conventional low-temperature fired ceramic base used was one in which the second conductor layer 3 was not disposed below the resistor layer 5, as shown in FIG. According to experiments conducted by the present inventors, the resistor layer 5 and the second
Improvement in the terminal effect was observed until the distance from the conductor layer 3 was approximately 100 μm.

[Table] Seat resistance at specified length * =

Claims (1)

[Scope of Claims] 1. A low-temperature fired ceramic circuit board made of low melting point glass and alumina, in which conductors 3 and 4 are made of a metal mainly composed of silver or silver-palladium, and a RuO ₂ - lath is used as a resistor 5. In, the resistor layer 5
A lower conductor layer 3 is arranged below the insulating layer 2 so as to correspond to the position of the resistor layer 5, and the length L of the lower conductor layer 3, the effective length l of the resistor layer 5, and Width W of lower conductor layer 3 and width W of resistor layer 5
A low-temperature fired ceramic circuit board, which satisfies the following relational expressions, L≧l, W≧w, and the distance between the resistor layer 5 and the lower conductor layer 3 is 100 μm or less. 2 Low melting point glass with CaO or MgO−Al ₂ O ₃ −
The low-temperature fired ceramic circuit board according to claim 1, characterized in that it is made of SiO ₂ -B ₂ O ₃ system.