JPH0512841B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a composite resistor.

BACKGROUND ART In recent years, electronic devices and devices have become smaller through the use of ICs and LSIs, and the reliability of the devices has also become higher.

On the other hand, there is a demand for miniaturization not only of ICs and LSIs but also of the circuit boards on which these are mounted.

In response to these demands, attempts have been made to create devices such as hybrid ICs in which resistors and capacitors are mounted and molded on a circuit board, and even as a composite board embedded within a single board.

As described above, the trend towards miniaturization is expected to become more and more popular in the future.

Technologies for such composite substrates include resistors,
It is known to form insulators and conductors using screen printing techniques. In addition, there are also resistors,
Attempts have also been made to form insulators using green sheets using lamination technology.

However, when a resistor is embedded in a circuit board like this, trimming it is extremely difficult. In addition, its properties vary greatly depending on the press pressure, binder removal conditions, firing conditions, etc. in the manufacturing process. Therefore, the circuits that attempt to advance these complexities are inevitably limited.

Laser trimming methods are known to remove such defects, but the first method is
As shown in the figure, only the resistor 13 of the layer located at a relatively shallow portion of the surfaces 11 and 12 could be trimmed, making it difficult to make the circuit board multilayered. Furthermore, the equipment used for these trimmings was also very expensive.

The object of the present invention is to provide a trimmable composite resistor that eliminates these conventional drawbacks. That is, the present invention provides a ceramic laminate having a structure in which an insulator layer, a conductor layer, and a resistor layer are laminated, and one or more conductor layers and one or more resistor layers are insulated on one surface of the laminate. A plurality of extraction electrodes are formed on the other surface of the laminate, and each of the plurality of extraction electrodes is exposed in layers through the conductor layer and the resistor layer. It is connected to either one through a through hole inside the laminate, and is connected to the conductor layer by shorting the conductor layer and the resistor layer on the surface where the conductor layer and the resistor layer are exposed. The present invention is a composite resistor characterized in that a predetermined resistance value is generated between a lead-out electrode connected to the resistor layer and a lead-out electrode connected to the resistor layer.

The present invention will be explained in detail below.

The raw insulator sheet used in manufacturing the composite resistor of the present invention is made of aluminum oxide 40 to 60% by weight,
Total amount 100 in composition range of crystallized glass 40-60% by weight
% of the mixed powder is made into a slurry with a binder, organic solvent, and plasticizer, and then formed into a slurry by slip casting film formation such as the doctor blade method.
A raw sheet of 20 μm to 300 μm is formed on a polyester film, peeled off, and then punched to a desired size to obtain a sheet. The composition of the crystallized glass powder used here is based on oxide conversion notation: lead oxide, boron oxide, silicon dioxide, group element oxides, group element (excluding carbon, silicon, and lead) oxides, Weight ratio 3-65%, 2-50%, 4 respectively
It is composed of compositions selected so that the total amount is 100% in the composition range of ~65%, 0.1-50%, and 0.02-20%.

The resistor sheet is made by mixing ruthenium dioxide powder and the crystallized glass powder used for the above-mentioned raw insulator sheet at a weight ratio of 10:90 to 50:50 so as to obtain the desired resistance value. After adding Celsolve, butyl carbitol, butyl butylphthalate, polyvinyl butyral, etc. to make a slurry, a film was formed in the same manner as the above-mentioned raw insulating sheet,
A sheet of 20 μm to 200 μm is obtained.

Furthermore, the paste used for electrode sheets and electrode terminals consists of a single metal such as Au, Ag, Pd, and Pt, or an alloy powder containing one or more of them, in an organic vehicle such as ethyl cellulose, α-terpineol, kerosene, or an aromatic hydrocarbon solvent. The mixture was kneaded to form a paste.

FIG. 2 shows the structure and lamination method of a composite resistor laminate according to an embodiment of the present invention,
FIG. 2 is a configuration diagram of a stacked body of eight composite resistors arranged in four layers with two resistors in each layer.

In the structure of this embodiment, the first layer of the laminate has an insulator sheet 22 with through holes 20 and extraction electrodes 21, and the second layer has a resistor sheet 23 whose end face is connected to the connection electrode 24. A resistor portion crimped so as to ride on it, its extraction pattern 25, and a terminal 26 for connection with the extraction electrode 21 of the first layer.
There is an insulating sheet 28 having through-hole terminals 27 for connection to conductors or resistors in other layers.

Further, the third layer has a conductor pattern 29 parallel to the resistor sheet 23, and like the resistor sheet 23, this conductor pattern 29 is also connected to the lead-out pattern 25 and the electrode of the first layer. There is an insulating sheet 30 having through-hole terminals 27 for connecting terminals 26 and a conductor or resistor in another layer.

Further, the fourth layer includes an insulating sheet 31 having only through-hole terminals 27 in order to separate the plurality of layers of resistance circuits. Here, a pair of the resistor sheet 23 and the conductor pattern 29 will be explained. When the resistor sheet 23 and the conductor pattern 29 are short-circuited (for example, by the conductive material 36 in FIG. 3), the resistance value corresponding to the short-circuit point will change. It is taken out between the take-out electrodes 21 and 21' (the outermost pair of the eight arranged) on the insulating sheet 22 via the take-out pattern 25 and the through-hole terminal 27. Similarly, for the set of resistor sheet and conductor pattern laminated further below, these short-circuit points (3 in Figure 3)
6) is extracted to a pair of extraction electrodes located inside the extraction electrodes 21 and 21' on the insulating sheet 22. In this way, four resistance values corresponding to a total of four sets of resistor sheets and conductor patterns are extracted to eight extraction electrodes on the insulator sheet 22. A similar arrangement is formed on the opposite side of the sheet 22.

These second to fourth layers are arranged repeatedly starting from the fifth layer, and the last layer has an insulator sheet 32 that serves as a dummy sheet.

Stack each sheet configured in this way and make 100
Laminated press at a temperature of ~130℃ and a pressure of 200~300m/ml, followed by a cutting process and a debinding process.
A sintered body with eight resistance circuits can be obtained by firing at a temperature of 1000°C to 1000°C.

FIG. 3 is an external perspective view of the sintered body, in which two cut surfaces 33 have a resistor end face 34 made of the resistor sheet 23 and a conductor end face 35 made of the conductor pattern 29. There is.

Furthermore, this resistor end face 34 and the conductor end face 35
A conductive material 36 (for example, Au,
A conductive paste (mainly composed of Ag, Pd, etc.) is baked onto it.

Since the composite resistor constructed in this manner has a laminated structure, the number of circuits can be freely increased or decreased in addition to the eight circuits described above, and all trimming can be easily performed.

Also, by providing a wiring pattern 37 on the surface where the first layer electrode 21 is located, the terminal 3
8 and terminal 39 can easily form an 8-stage series-connected resistor network as shown in FIG.

The resistor network in this example has a total of 18 layers consisting of two layers of insulating sheets for separating the plurality of resistor circuits, and the resistor sheet is 1 mm x 7 mm, with a resistance of 150 Ω. /1 resistor is constructed on a 10mm x 5mm square plate chip, making it a very compact composite resistor that can be trimmed.

FIG. 5 shows an example of the external appearance of one structure of the composite resistor of the present invention, and the terminal surface of the sintered body 51 has a lead-out terminal 5.
I have 2 children. Furthermore, trimming is performed to obtain circuit constants that utilize this composite resistor, and an exterior mold 54 is formed.

As is clear from the above explanation, the composite resistor of the present invention allows multiple resistors to be combined into a small chip, and furthermore, all of these resistors can be trimmed, resulting in resistance value accuracy. It can be applied to important circuits.

Although green sheets are used for the resistors in this embodiment, it is clear that the same effect can be obtained even if these resistors are formed by screen printing. In addition, there are no restrictions on the pattern of extraction from the internally layered resistor or the position of the electrode, and a configuration as a resistance module to be used can be easily obtained.

Furthermore, it is clear that the same effect can be obtained by using a green sheet made of a material other than the insulating material used in the present invention that can be co-fired. Moreover, the cut shape of the laminate is not limited to square plates,
A trimmable composite resistor can also be obtained by arranging the end face of the resistor sheet and the end face of the conductor in the same way as described above on the circumference cut into a circular shape.

[Brief explanation of drawings]

Figure 1 is a structural diagram of a conventional composite variable resistor. Second
The figure is a laminated structure diagram of a composite resistor according to an embodiment of the present invention. FIG. 3 is an external view of the composite resistor obtained in FIG. 2. FIG. 4 is a diagram showing a resistance network obtained by the composite resistor of the present invention. FIG. 5 is a perspective view showing the structure of a composite resistor with lead terminals and exterior molding. In the figure, 11 and 12... upper and lower surfaces of the composite resistor, 13... resistance, 20... through hole, 2
1, 21'... Electrode for extraction, 22... Insulator sheet, 23... Resistor sheet, 24... Electrode for connection, 25... Pattern for extraction, 26... Terminal for connection, 27... Through hole Terminal, 28... Insulator sheet, 29... Conductor pattern, 30... Insulator sheet, 31... Insulator sheet, 32... Insulator sheet, 33... Cut surface, 34... Resistor end surface, 35 ... conductor end surface, 36 ... conductive substance,
37... Wiring pattern, 38 and 39... Terminal,
51...Sintered body, 52...Takeout terminal, 53...
...Conductive material, 54...Exterior mold.

Claims (1)

[Claims] 1 A ceramic laminate having a structure in which an insulator layer, a conductor layer, and a resistor layer are laminated, and one or more conductor layers and a resistor layer are arranged on one surface of the laminate with an insulator layer interposed therebetween. A plurality of extraction electrodes are formed on the other surface of the laminate, and each of the plurality of extraction electrodes is formed on one of the conductor layer and the resistor layer. The conductor layer and the resistor layer are connected through a through hole inside the laminate, and the conductor layer and the resistor layer are short-circuited on the surface where the conductor layer and the resistor layer are exposed. A composite resistor characterized in that a predetermined resistance value is generated between an electrode and an extraction electrode connected to the resistor layer.