Composite device and manufacturing method thereof

A resistance element, a capacitor and an intermediate electrode are formed on a substrate. The capacitor and the resistance element are connected with the intermediate electrode interposed. Two terminal electrode portions are connected to each other through the intermediate electrode.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention generally relates to a composite device. More 
specifically, the present invention relates to a composite device having a 
thick film type capacitor and a thick film type resistor formed on a chip 
type insulating substrate, and adapted to enable solder mounting on a 
printed board or the like. The present invention also relates to the 
method of manufacturing such a composite device. 
2. Description of the Background Art 
In a conventional composite device, terminal electrode portions for 
connection are formed on left and right end portions of a chip type 
insulating substrate. On an upper surface of the insulating substrate, a 
thick film type capacitor and a thick film type resistor are formed. One 
electrode of the capacitor is connected to one end of the resistor. The 
other electrode of the capacitor is connected to one of the terminal 
electrode portions mentioned above. The other end of the resistor is 
connected to the other one of the terminal electrode portions. The 
terminal electrode portions provided on the left and right end portions of 
the insulating substrate are soldered to a printed board. 
The conventional composite device structured as described above suffers 
from the following problems. 
As already described, in the conventional composite device, a capacitor and 
a resistor are connected in series to each other on one chip type 
insulating substrate. Therefore, application thereof is limited to serial 
connection of the capacitor and the resistor in one interconnected 
circuitry. As a result, when a capacitor and a resistor are to be provided 
parallel to each other in one interconnected circuitry, or when either one 
of the capacitor and the resistor is to be provided in one interconnected 
circuitry, the composite device cannot be used. This makes the range of 
application of the conventional composite device very narrow. 
Therefore, when a parallel circuitry including a capacitor C and a resistor 
R is to be formed as shown in FIG. 11, a chip type capacitor and a chip 
type resistor have to be mounted separately on a printed board. When a 
filter circuit is to be formed by a capacitor C and a resistor R as shown 
in FIG. 12 or 13, a chip type capacitor and a chip type resistor have to 
be mounted separately on a printed board. Therefore, the cost necessary 
for mounting is significantly increased, mounting density on the printed 
board is lower and eventually, the size of the printed board is made 
large. 
SUMMARY OF THE INVENTION 
Therefore, an object of the present invention is to provide a composite 
device improved to allow for wider range of applications. 
Another object of the present invention is to provide a composite device 
improved to increase density of mounting on a printed board. 
A still further object of the present invention is to provide a composite 
device improved to significantly reduced cost for mounting on a printed 
board. 
A still further object of the present invention is to provide a composite 
device improved to allow reduction in size and weight of a printed board. 
A still further object of the present invention is to provide a 
manufacturing method enabling manufacturing of a number of such composite 
devices from one ceramic plate as a raw material. 
The above described objects of the present invention can be attained by the 
composite device including a substrate having first, second, third and 
fourth end surfaces, wherein the first and second end surfaces oppose to 
each other and the third and fourth end surfaces oppose to each other. A 
first end electrode is provided on the substrate near the first end 
surface. A second end electrode is provided on the substrate near the 
second end surface. An intermediate electrode is provided on the substrate 
between the first and second end electrodes. A thick film type capacitor 
is provided on the substrate between the first end electrode and the 
intermediate electrode. A thick film type resistance element is provided 
on the substrate between the second end electrode and the intermediate 
electrode. A first terminal electrode portion is provided on the first end 
surface to be electrically connected to the first end electrode. A second 
terminal electrode portion is provided on the second end surface to be 
electrically connected to the second end electrode. A third terminal 
electrode portion is provided on the third end surface to be electrically 
connected to the intermediate electrode. The thick film type capacitor 
includes a lower electrode film provided on the substrate and having one 
end connected to the intermediate electrode, and an upper electrode film 
provided on the lower electrode film with a dielectric film interposed, 
having one end electrically connected to the first end electrode. 
According to the present invention, a capacitor and a resistance element 
are connected in series between the first and second terminal electrode 
portions. The capacitor and the resistance element are connected to the 
third terminal electrode portion. Therefore, when mounted on a printed 
board, by appropriately selecting and disconnecting a mid portion of an 
interconnected circuitry and by connecting resulting end portions of the 
disconnected portion to the first terminal electrode portion and the 
second terminal electrode portion respectively, it becomes possible to 
connect the capacitor and the resistor in series. By appropriately 
selecting and disconnecting a mid portion of an interconnected circuitry 
and connecting the resulting one end to the first and second terminal 
electrode portions and the other end to the third terminal electrode 
portion, it is possible to connect the capacitor and the resistor parallel 
to each other. Further, by appropriately selecting and disconnecting a mid 
portion of an interconnection circuitry, connecting one of the resulting 
end to the first or second terminal electrode portion and connecting the 
other end to the third terminal electrode portion, it is possible to form 
either a capacitor or a resistor in the interconnected circuitry. Further, 
the present invention is applicable when one interconnected circuitry is 
to be connected in T shape to another interconnected circuitry. In that 
case, the first terminal electrode portion is connected to one end of one 
interconnected circuitry, the second terminal electrode portion is 
connected to the other end of this one interconnected circuitry, and the 
third terminal electrode portion is connected to another interconnected 
circuitry. 
According to the present invention, applications of a surface mounting type 
composite device including a capacitor and a resistance element can be 
made wider. More specifically, applications other than provision of the 
capacitor and the resistor connected in series in one interconnected 
circuitry are possible. Further, the parallel circuit such as shown in 
FIG. 11 as well as the CR filter circuit such as shown in FIGS. 12 and 13 
may be provided by only one component. Therefore, the cost for mounting on 
a printed board can significantly be reduced. Further, mounting density on 
the printed board is increased, enabling reduction in size and weight of 
the printed board. 
Further, by providing the third terminal electrode portion on each of the 
third and fourth end surfaces of the insulating substrate, it is possible 
to provide a jumper component such as disclosed in Japanese Patent 
Laying-Open No. 56-35500 and Japanese Utility Model Laying-Open No. 
62-150874. This further increases possible applications. 
In the method of manufacturing composite devices in accordance with another 
aspect of the present invention, a ceramic plate sectioned such that a 
plurality of substrates each having first, second, third and fourth end 
surfaces wherein the first and second end surfaces oppose to each other 
and the third and fourth end surfaces oppose to each other and wherein 
through holes each exposing part of the third and fourth end surfaces are 
formed in the ceramic plate is prepared. A third terminal electrode 
portion is formed on an inner surface of the through hole. On the ceramic 
substrate, a first end electrode is formed near the first end surface, a 
second end electrode is formed near the second end surface, and an 
intermediate electrode electrically connected to the third terminal 
electrode portion is formed between the first and second end electrodes. A 
thick film type capacitor is formed on the ceramic plate between the first 
end electrode and the intermediate electrode. A thick film type resistance 
element is formed on the ceramic plate between the second end electrode 
and the intermediate electrode. The ceramic plate is cut and divided such 
that the first and second end surfaces are exposed. A first terminal 
electrode electrically connected to the first end electrode is formed on 
the first end surface, and a second terminal electrode portion 
electrically connected to the second end electrode is formed on the second 
end surface. The divided ceramic plate is further cut and divided so that 
the third and fourth end surfaces are exposed. 
According to this method, a plurality of composite devices each having the 
above described structure can be manufactured simultaneously at a low cost 
from one ceramic plate as a row material. 
The foregoing and other objects, features, aspects and advantages of the 
present invention will become more apparent from the following detailed 
description of the present invention when taken in conjunction with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Embodiments of the present invention will be described with reference to 
the figures. 
Referring to FIGS. 1, 2 and 3, the composite device in accordance with the 
present invention includes an insulating substrate 1 formed of ceramics or 
the like and configured as a rectangular chip. On insulating substrate 1, 
end electrodes 2 and 3 are formed. End electrodes 2 and 3 are formed on 
left and right end portions of insulating substrate 1 in the figure. An 
intermediate electrode 4 is formed between end electrodes 2 and 3. A lower 
electrode film 5a extends from an end portion of intermediate electrode 4. 
Intermediate electrode 4 and lower electrode film 5a are formed 
integrally. Since intermediate electrode 4 is integrated with lower 
electrode film 5a, end electrodes 2, 3, intermediate electrode 4 and lower 
electrode film 5a can be prepared from the same material and at the same 
time. It is preferred that plating-stable and solder-stable material is 
used as the material, because intermediate electrode 4 and lower electrode 
film 5a are treated with plating and solder. Lower electrode film 5a is 
covered with a dielectric film 5b. An upper electrode film 5c is formed on 
lower electrode film 5a with dielectric film 5b interposed. Upper 
electrode film 5c is electrically connected to end electrode 2. Lower 
electrode film 5a, dielectric film 5b and upper electrode film 5c 
constitute a thick film type capacitor 5. A thick film type resistor 6 is 
provided on insulating substrate 1. Resistor 6 is formed of a resistive 
film 6a. Resistive film 6a is provided between end electrode 3 and 
intermediate electrode 4. On an end surface 1a of insulating substrate 1, 
a first terminal electrode portion 7 electrically connected to end 
electrode 2 is provided. On the other end surface lb of insulating 
substrate 1, a second terminal electrode portion 8 electrically connected 
to end electrode 3 is provided. Between the third end surface 1c and the 
fourth end surface 1d of insulating substrate 1, third terminal electrode 
portions 9, 9 electrically connected to intermediate electrode 4 are 
formed, respectively. 
Capacitor 5 and resistor 6 are entirely covered by a cover coat 10 formed 
of glass or a synthetic resin. Cover coat 10 may cover only the portions 
of the substrate having capacitor 5 and resistor 6. Cover coat 10 may have 
a single-layered structure or two or three layered structure. 
FIG. 4 is an equivalent circuit diagram of the composite device shown in 
FIGS. 1 to 3. Between the first and second terminal electrode portions 7 
and 8, capacitor 5 and resistor 6 are connected in series, with 
intermediate electrode 4 interposed. Two third terminal electrode portions 
9, 9 are connected to each other by intermediate electrode 4. 
Mounting of the composite device in accordance with the present embodiment 
on a printed board will be described. 
A mid portion of one interconnected circuitry is appropriately selected and 
disconnected, and resulting disconnected portions are connected to the 
first and second terminal electrode portions 8, respectively, then a 
structure in which capacitor 5 and resistor 6 are connected in series is 
provided in one interconnected circuitry. By appropriately selecting and 
disconnecting a portion in one interconnected circuitry, connecting one 
end of the disconnected point to the first and second terminal electrode 
portions 7 and 8, and connecting the other end to one of the third 
terminal electrode portions 9, a structure including parallel connection 
of capacitor 5 and resistor 6 is provided in one interconnected circuitry. 
Further, by appropriately selecting and disconnecting a portion in one 
interconnected circuitry, connecting one end of the disconnected portion 
to the first or second terminal electrode portion 7 or 8, and connecting 
the other end to one of the third terminal electrode portions 9, a 
structure including capacitor 5 or resistor 6 in one interconnected 
circuitry is provided. Further, when an interconnected circuitry is to be 
connected in T shape to another interconnected circuitry, the first and 
second terminal electrode portions 7 and 8 should be connected to one and 
the other ends of the aforementioned another interconnected circuitry, and 
one of the third terminal electrode portions 9, 9 should be connected to 
said one interconnected circuitry. 
By using both of the third terminal electrode portions 9, 9, it is also 
possible to provide a jumper component providing power over the 
aforementioned one interconnection circuit, such as disclosed in Japanese 
Patent Laying-Open No. 56-35500 and Japanese Utility Model Laying-open No. 
62-150874. 
The method of manufacturing the composite device shown in FIGS. 1 to 3 will 
be described in the following. 
Referring to FIG. 5, a ceramic plate A sectioned to provide a plurality of 
insulating substrate 1 each having first, second, third and fourth end 
surfaces 1a, 1b, c and 1d, with the first and second end surfaces 1a and 
1b opposing to each other and the third and fourth end surfaces 1c and 1d 
opposing to each other, wherein through holes A1 each exposing parts of 
the third and fourth end surfaces 1c and 1d are formed, is prepared. Here, 
a plurality of insulating substrates 1 are connected integrally, and 
therefore the first to fourth end surfaces are not visible. However, for 
convenience, description is given assuming presence of the first, second, 
third and fourth end surfaces. 
Referring to FIGS. 1 (finished product) and 5, the third terminal electrode 
portion 9 is formed on an inner surface of each through hole A1. Referring 
to FIGS. 1 and 6, end electrodes 2 and 3 are formed at prescribed 
positions on an upper surface of ceramic plate A. Simultaneously with 
formation of end electrodes 2 and 3, an intermediate electrode 4 having a 
lower electrode film 5a integrally connected thereto is formed. 
Referring to FIGS. 1 and 7, a resistive film 6a is formed at a prescribed 
position on ceramic plate A. Resistive film 6A is subjected to trimming 
adjustment so that resistance value of resistive film 6a is within a 
prescribed tolerable range. In this manner, resistor 6 is completed. 
Referring to FIGS. 1 and 8, a dielectric film 5b is formed at a prescribed 
position on ceramic plate A. An upper electrode film 5c is formed on 
dielectric film 5b. In this manner, capacitor 5 is completed. 
Referring to FIGS. 1 and 9, a cover coat 10 is formed at a prescribed 
position on an upper surface of ceramic plate A. Referring to FIGS. 9 and 
10, ceramic plate A is cut and divided such that the first and second end 
surfaces 1a and 1b of insulating substrate 1 are exposed, thus forming 
bar-shaped ceramic plates A'. First terminal electrode portion 7 is formed 
on first end surface 1a and the second terminal electrode portion 8 is 
formed on the second end surface 1a. 
Though not shown, each bar-shaped ceramic plate A' is cut and divided such 
that the third and fourth end surfaces 1c and 1d are exposed. In this 
manner, a plurality of composite devices shown in FIGS. 1 to 3 can be 
formed simultaneously from one ceramic plate A as a raw material. 
Although the present invention has been described and illustrated in 
detail, it is clearly understood that the same is by way of illustration 
and example only and is not to be taken by way of limitation, the spirit 
and scope of the present invention being limited only by the terms of the 
appended claims.