Chip network resistor and method for manufacturing same

A chip-like network resistor is disclosed which is reduced in variation in resistance of terminal electrodes. A substrate (1) is formed on both ends (3, 5) with a plurality of recesses (7), at each of which a terminal electrode (17) connected to a thick-film electrode (9) is arranged. The terminal electrodes (17) each are constituted of a thin metal film electrode layer (19) and two plated layers (21, 23). The thin metal film electrode layer (19) includes a front surface electrode section (19a) formed on a front surface (1a) of the substrate (1) so as to overlap with the thick-film electrode (9), a side surface electrode section (19b) connected to the front surface electrode section (19a) and arranged so as to entirely cover an inner surface of the recess (7) and a rear surface electrode section (19c) formed on a rear surface (1b) of the substrate (1) and connected to the side surface electrode section (19b). The front surface electrode section (19a) of the thin metal film electrode layer (19) is formed so as to fully surround a periphery of one of open ends of each of the recesses 7.

TECHNICAL FIELD 
This invention relates to a chip-like network resistor having a plurality 
of resistance elements formed on a substrate and a method for 
manufacturing the same. 
BACKGROUND ART 
The inventors disclosed a general structure of a chip-like network resistor 
in Japanese Patent Application Laid-Open Publication No. 78701/1995. The 
chip-like network resistor disclosed in the publication includes an 
insulating substrate which is formed on each of both ends thereof with a 
plurality of recesses, a plurality of thick-film electrodes arranged 
adjacently to the recesses, and resistance elements each arranged between 
each pair of thick-film electrodes. Also, the resistor includes terminal 
electrodes each are arranged so as to cover an inner surface of the recess 
and connected to the thick-film electrode corresponding thereto. The 
terminal electrodes each include a thin metal film electrode layer and a 
plated electrode layer of a two-layer structure arranged so as to cover 
the thin metal film electrode layer. The thin metal film electrode layer 
includes a front surface electrode section formed on a front surface of 
the insulating substrate so as to overlap with the thick-film electrode, a 
side surface electrode section connected to the front surface electrode 
section and arranged so as to cover a whole inner surface of the recess 
and a rear surface electrode section connected to the side surface 
electrode section and arranged on a rear surface of the insulating 
substrate. 
Conventionally, manufacturing of such a resistor is carried out by first 
providing a large-sized insulating substrate which is formed on a front 
surface thereof with lattice-like separation grooves constituted of a 
plurality of longitudinal grooves and a plurality of lateral grooves. 
Also, the insulating substrate is formed with a plurality of through-holes 
of a circular shape in cross section, each of which is arranged along a 
portion of the lateral groove positioned between each adjacent two of the 
longitudinal grooves. Thereafter, the large-sized insulating substrate is 
formed on the front surface thereof with a plurality of thick-film 
electrodes (primary electrodes), which are positioned on regions each 
interposed between each adjacent two of the lateral grooves and between 
each adjacent two of the longitudinal grooves while being in proximity to 
each of the through-holes. Then, the regions each are formed thereon with 
a plurality of resistance elements in a manner to extend between two of 
the thick-film electrodes opposite to each other, followed by covering of 
the resistance elements with a glass coating. Then, a resistance of the 
resistance element is measured by means of a probe electrode for 
measurement which is kept contacted at a distal end or tip thereof with 
the thick-film electrodes positioned on both sides of the resistance 
element. Then, laser trimming is carried out depending on the resistance 
measured, to thereby adjust the resistance to a desired value. After the 
trimming, the glass coating is covered with glass or resin. Then, the 
through-holes each are covered at both ends and an inner surface thereof 
with a thin metal film and then the large-sized insulating substrate is 
separated into a plurality of chip-like elements along the longitudinal 
and lateral grooves. Lastly, the chip-like elements each are subject on an 
electrode section thereof to plating. 
The separation of the substrate into the chip-like elements causes the 
through-holes to be cut, leading to formation of the recesses and thin 
metal film electrode layer described above. The front surface electrode 
section of the thin metal film electrode layer is merely required to 
permit the thick-film electrode and side surface electrode section to be 
connected to each other, thus, the prior art does not pay any specific 
attention to a configuration of the front surface electrode section. 
Therefore, the conventional resistor is not constructed in such a manner 
that the front surface electrode section is arranged so as to fully 
surround a circumference or periphery of an opening of the recess defined 
in a thickness direction of the insulating substrate. 
Such construction of the conventional resistor does not cause any serious 
problem so long as the resistor is formed into a large size. However, a 
reduction in size of the chip-like resistor causes the components thereof 
to be reduced in size correspondingly, to thereby render adjustment of the 
resistance by trimming highly troublesome. Also, a reduction in resistance 
of the resistance element causes a variation in resistance of the terminal 
electrode to substantially affect a resistance of the resistance element. 
Unfortunately, the conventional resistor causes a variation in resistance 
of the terminal electrode to be increased. Also, a decrease in size of the 
chip-like resistor substantially fails to increase a distance between the 
electrodes adjacent to each other. Further, the conventional resistor 
causes a corner of each of the recesses to be readily broken when the 
large-sized insulating substrate is separated into the individual 
chip-like elements. 
It is an object of the present invention to provide a chip-like network 
resistor which is capable of minimizing a variation in resistance of 
terminal electrodes. 
It is another object of the present invention to provide a chip-like 
network resistor which is capable of effectively preventing positional 
deviation thereof during soldering thereof onto an electrode on a circuit 
board. 
It is a further object of the present invention to provide a chip-like 
network resistor which is capable of minimizing a variation in dimension 
or distance between electrodes adjacent to each other. 
It is still another object of the present invention to provide a chip-like 
network resistor which is capable of facilitating measurement of a 
resistance during trimming. 
It is a still further object of the present invention to provide a 
chip-like network resistor which is capable of minimizing breakage of a 
corner of a recess when a large-sized insulating substrate is cut. 
DISCLOSURE OF THE INVENTION 
In accordance with the present invention, a chip-like network resistor is 
provided. The chip-like network resistor includes an elongated insulating 
substrate. The elongated insulating substrate is formed with a pair of 
ends in a manner to extend in a longitudinal direction thereof and be 
opposite to each other in a width direction thereof. The ends each are 
formed with a plurality of recesses which are open on an outside thereof 
in the width direction and on both sides thereof in a thickness direction 
of the insulating substrate and are formed into a substantially 
semi-circular shape in cross section. The insulating substrate may be made 
of a ceramic material. The chip-like network resistor also includes a 
plurality of thick-film electrodes each formed on a front surface of the 
insulating substrate and arranged in a manner to be adjacent to one of 
open ends of each of the recesses which are open in the thickness 
direction. The term "thick-film electrode" used herein means an electrode 
formed of a conductive paste. The conductive paste may be constituted by a 
conductive glass paste obtained, for example, by mixing a glass binder 
with a conductive powder of Ag, Ag--Pd or the like. A plurality of 
resistance elements each are formed on the front surface of the insulating 
substrate in a manner to extend between the thick-film electrode formed on 
a side of one of the ends of the insulating substrate and the thick-film 
electrode formed on a side of the other of the ends of the insulating 
substrate. The resistance elements each may be in the form of either a 
thick film, which may be made of a paste for a resistance element or a 
thin film. Then, an overcoating made of an insulating material such as a 
glass into a layer structure and including at least one layer is arranged 
so as to cover the resistance elements. 
Also, the chip-like network resistor includes a plurality of terminal 
electrodes arranged in a manner to correspond to the thick-film 
electrodes, respectively. The terminal electrodes each include a thin 
metal film electrode layer and at least one plated electrode layer for 
covering the thin metal film electrode layer. The thin metal film 
electrode layer includes a front surface electrode section formed on the 
front surface of the insulating substrate so as to overlap with the 
thick-film electrode, a side surface electrode section connected to the 
front surface electrode section and arranged so as to entirely cover an 
inner surface of the recess, and a rear surface electrode section formed 
on a rear surface of the insulating substrate and connected to the side 
surface electrode section. 
The thin metal film electrode layer may be made by thin film formation 
techniques such as metal vapor deposition, metal sputtering or the like. 
Metals for the thin film include, for example, nickel-chromium alloy, pure 
metal such as copper, and the like. Also, the plated electrode layer may 
be constructed into a two-layer structure including a nickel plated layer 
and a solder plated layer laminated on the nickel plated layer. The plated 
electrode layer exhibits increased solderability. 
In the present invention, the front surface electrode section of the thin 
metal film electrode layer is featured to fully surround a circumference 
of one open end of the recess. If the front surface electrode section 
fails to fully surround one of the open ends of the recess as seen in the 
prior art, a length of a connection between the front surface electrode 
section and the end of the side surface electrode section covering the 
inner surface of the recess on the side of one opening thereof is 
substantially varied, leading to a substantial variation in resistance of 
the terminal electrode. On the contrary, the present invention is so 
constructed that the end of the side surface electrode covering the inner 
surface of the recess on the side of one opening thereof is connected to 
the front surface electrode section. Such construction prevents a 
substantial variation in resistance of the terminal electrode. Formation 
of the front surface electrode section into a configuration which fully 
surrounds the periphery or circumference of one open end of the recess 
permits the front surface electrode section to act as a reinforcing member 
for enhancing mechanical strength of a corner of the recess, to thereby 
prevent breakage of the corner of the recess during cutting of the 
large-sided insulating substrate. 
The front surface electrode section of the thin metal film electrode layer 
is preferably curved so as to permit a portion thereof overlapping the 
thick-film electrode to be projected toward the resistance element. Such 
formation of the front surface electrode section facilitates formation of 
holes in a mask used for formation of the thin metal film electrode layer 
and down-sizing of the resistor. 
The rear surface electrode section of the thin metal film electrode layer 
is arranged so as to surround a periphery of the other open end of the 
recess which is open in the thickness direction (and is preferably 
arranged so as to fully surround the other open end). Also, the rear 
surface electrode section is preferably formed into a configuration which 
permits a width dimension to be decreased from the other open end inwardly 
in the width direction of the substrate. (In other words, it is preferably 
formed into a curved configuration which permits it to extend inwardly of 
the other open end and projected at a distal end thereof.) Such 
configuration of the rear surface electrode section permits a portion of 
each of the plated layers covering the rear surface electrode section to 
have the same shape. This permits molten solder between a rear surface 
electrode and a soldered electrode arranged on the front surface of a 
circuit board to tend to move toward a central portion of the rear surface 
electrode section, when the resistor is connected to the soldered 
electrode by soldering. This prevents irregular shifting of the resistor 
during the soldering, so that a self-alignment function of naturally 
locating the resistor substantially at a predetermined position may be 
exhibited. This facilitates soldering and minimizes a failure in 
soldering. The rear surface electrode may be formed into a configuration 
of fully surrounding the opening of the recess. This substantially fully 
prevents breakage of the corner of the recess. 
The thick-film electrode may be formed into any desired configuration. In 
the prior art, the thick-film electrode is formed so as to conform to an 
outer periphery of the recess. However, such formation of the thick-film 
electrode, when the end of the thick-film electrode overlaps the lateral 
groove of the separation grooves, causes a conductive paste for the 
thick-film electrode to flow along the lateral groove, to thereby decrease 
a distance between the terminal electrodes adjacent to each other, leading 
to short-circuiting between the electrodes in the worst case; in the case 
that there occurs significant misregistration in printing during formation 
of the thick-film electrode. Also, misregistration in printing causes the 
conductive paste to flow into the recess. This leads to adhesion of the 
conductive paste to the mask during formation of the thick-film electrode, 
resulting in the subsequent operation of printing the thick-film electrode 
being highly hindered. In view of the foregoing, in the present invention, 
the thick-film electrodes each are positioned inwardly in the width 
direction from the recess and formed so that an end edge thereof facing 
the recess extends along an edge of the ends of the insulating substrate. 
Such construction effectively prevents intrusion of the conductive paste 
into the recess due to misregistration in printing, as well as a reduction 
in distance between the terminal electrodes due to intrusion of the 
conductive paste into the lateral groove, leading to an increase in yields 
in manufacturing of the insulating substrate provided with the thick-film 
electrode. In particular, when the resistor is down-sized, such formation 
of the thick-film electrode further enhances the above-described 
advantage. 
Manufacturing of the chip-like network resistor is attained while 
facilitating trimming of the resistor. 
For this purpose, first of all, a large-sized insulating substrate is 
provided which is formed on at least a front surface thereof with 
lattice-like separation grooves constituted of a plurality of longitudinal 
grooves and a plurality of lateral grooves and provided with a plurality 
of through-holes of a circular shape in cross section. The through-holes 
each are arranged along a portion of the lateral groove positioned between 
each adjacent two of the longitudinal grooves. Then, a plurality of 
thick-film electrodes are formed on a plurality of regions of the front 
surface of the large-sized insulating substrate in a manner to be in 
proximity to the through-holes, respectively. The regions each are defined 
at a position interposed between each adjacent two of the lateral grooves 
and between each adjacent two of the longitudinal grooves. Then, a 
plurality of resistance elements are formed on each of the regions in a 
manner to extend between each adjacent two of the thick-film electrodes 
opposite to each other. Then, the resistance elements on each of the 
regions are covered with a glass coating. Thereafter, front surface 
electrodes, inner electrodes and rear surface electrodes are formed of a 
thin metal film, wherein the front surface electrode is formed so as to 
fully surround a periphery of one of openings of each of the through-holes 
and overlap each of the thick-film electrodes, the inner electrode is 
formed so as to cover an inner surface of each of the through-holes, and 
the rear surface electrode is formed so as to fully surround a periphery 
of the other opening of the through-hole. Subsequently, a probe electrode 
for measurement is contacted at a distal end thereof with each of the 
front surface electrodes positioned on both sides of the resistance 
element to measure a resistance of the resistance element, to thereby 
subject the resistance element to laser trimming depending on the 
resistance measured. The glass coating is covered with either an 
additional glass coating or a resin coating after the trimming and then 
the large-sized insulating substrate is divided into a plurality of 
chip-like elements along the longitudinal grooves and lateral grooves. 
Lastly, an electrode section of each of the chip-like elements is subject 
to plating. 
In the method of the present invention, the electrode is made of the thin 
metal film with respect to each of the through-holes after formation of 
the resistance element, so that a resistance of the resistance element may 
be measured using the thin metal film as an electrode for measurement. 
This permits an area of the electrode for measurement to be increased as 
compared with the prior art, so that measurement of the resistance may be 
facilitated while reducing an error in the measurement. When the resistor 
is small-sized, a resistance of the resistance element may be measured 
while keeping the distal end of the probe electrode for measurement fitted 
in each of the through-holes. This ensures positive contact between the 
probe electrode for measurement and the electrode for measurement, to 
thereby prevent occurrence of an error in the measurement.

BEST MODE FOR CARRYING OUT INVENTION 
Now, the present invention will be detailedly described with reference to 
the accompanying drawings which show an embodiment thereof. FIG. 1 is a 
plan view showing an embodiment of a chip-like network resistor according 
to the present invention and FIG. 2 is a sectional view taken along line 
II--II of FIG. 1. In FIGS. 1 and 2, reference numeral 1 designates an 
elongated insulating substrate made of a ceramic material. The insulating 
substrate 1 is formed on a pair of ends 3 and 5 thereof extending in a 
longitudinal direction thereof and opposite to each other in a width 
direction thereof (a direction thereof perpendicular to the longitudinal 
direction thereof and a thickness direction thereof or a vertical 
direction normal to the sheet of FIG. 1) with four recesses 7, which are 
open outwardly in the width direction thereof and on both sides in the 
thickness direction thereof and formed into a substantially semi-circular 
shape in cross section. (Thus, eight such recesses are arranged on both 
sides thereof.) Formation of such recesses 7 will be described 
hereinafter. 
The substrate 1 is formed on a front surface la thereof with a plurality of 
primary electrodes or thick-film electrodes 9, each of which is arranged 
in a manner to be adjacent to one of both open ends of each of the 
recesses 7 in the thickness direction. The thick-film electrodes 9 each 
are made of a conductive glass paste such as an Ag--Pd glass paste or the 
like. The thick-film electrodes 9 each are formed at an end edge of a 
portion 9a thereof positioned on a side of each of the recesses 7 with an 
arcuate portion curved or depressed in conformity to the opening of the 
recess 7. The thick-film electrodes 9 each are arranged so as to define a 
gap of a slight size between the opening of the recess 7 and the arcuate 
portion of the end edge of the portion 9a thereof. The gap thus formed 
functions to prevent a conductive paste for forming the thick-film 
electrode 9 from flowing into the recess 7. The thick-film electrode 9 
also has a portion 9b positioned opposite to the portion 9a (or inwardly 
in the width direction of the substrate 1), which is formed into a width 
dimension (or a dimension in a direction along the longitudinal direction 
of the substrate 1) larger than the portion 9a. 
The chip-like network resistor of the illustrated embodiment also includes 
a plurality of resistance elements 11, each of which is formed on the 
front surface 1a of the substrate 1 in a manner to extend between the 
thick-film electrode 9 formed on a side of the one end 3 of a pair of the 
ends 3 and 5 of the substrate 1 and the thick-film electrode 9 formed on a 
side of the other end 5 of the substrate 1. In the illustrated embodiment, 
the resistance elements 11 each are made of a glass paste for a resistance 
element containing a powder of ruthenium oxide. In the illustrated 
embodiment, the resistance elements 11 each are constructed so as to have 
substantially the same resistance. 
Four such resistance elements 11 are entirely covered with a glass coating 
13 formed of lead borosilicate glass. The glass coating 13 is arranged for 
the purpose of facilitating laser trimming and protecting the resistance 
elements. The glass coating 13 is merely required to cover at least a 
portion of each of the resistance elements 11 between the thick-film 
electrodes 9. Thus, it is not necessarily required to entirely cover each 
of the resistance elements 11. 
Then, the glass coating 13 is covered with a protective coating 15 made of 
lead borosilicate glass, thermosetting synthetic resin such as epoxy resin 
or the like. The protective coat 15 is arranged so as to entirely cover 
the glass coating 13 and partially cover the thick-film electrodes 9. The 
glass coating 13 and protective coating 15 cooperate with each other to 
constitute an overcoating of a layer structure including at least one 
layer. The protective coating 15 is formed thereon with the numeral of 103 
for display by printing of a resin paste. 
The chip-type network resistor of the illustrated embodiment also includes 
a plurality of terminal electrodes 17 arranged in a manner to correspond 
to the thick-film electrodes 9, respectively. The terminal electrodes each 
are constructed into a three-layer structure including a thin metal film 
electrode layer 19, a nickel plated layer 21 and a solder plated layer 23. 
The thin metal film electrode layer 19 is formed of thin film forming 
metal selected from the group consisting of nickel-chromium alloy and 
copper using thin film formation techniques such as vapor deposition, 
sputtering or the like. The thin metal film electrode layer 19 includes a 
front surface electrode section 19a formed on the front surface of the 
substrate 1 so as to overlap with the thick-film electrode 9, a side 
surface electrode section 19b connected to the front surface electrode 
section 19a and arranged so as to entirely cover an inner surface of the 
recess 7, and a rear surface electrode section 19c formed on a rear 
surface of the substrate 1 and connected to the side surface electrode 
section 19b. The front surface electrode section 19a is arranged so as to 
fully surround a circumference or periphery of one open end of the recess 
7 and curved so as to permit the portion thereof overlapping the 
thick-film electrode 9 to be projected toward the resistance element 11. 
In the illustrated embodiment, the front surface electrode section 19 has 
a contour configuration formed into a substantially semi-elliptic shape. 
The rear surface electrode section 19c, as shown in FIG. 3, is arranged so 
as to fully surround a circumference or periphery of the other open end of 
the recess 7 which is open in the thickness direction. Also, the rear 
surface electrode section 19c is formed into a configuration which permits 
a width dimension thereof to be decreased from the other open end inwardly 
in the width direction of the substrate 1 (or upwardly from the sheet of 
FIG. 3). (In other words, it is formed into a curved configuration which 
permits it to extend inwardly of the other open end and projected at a 
distal end thereof.) Such configuration of the rear surface electrode 19c 
permits a portion of each of the two plated layers 21 and 23 covering the 
rear surface electrode section 19c to have the same configuration. This 
permits molten solder between a rear surface electrode (which is an 
electrode portion formed by the rear surface electrode section 19c and the 
plated layers 21 and 23 covering the rear surface electrode 19c) and a 
soldered electrode arranged on the front surface of a circuit board to 
tend to move toward a central portion of the rear surface electrode 
section 19c, when the resistor is connected, by soldering, to a soldered 
electrode arranged on a circuit board. This prevents irregular shifting of 
the resistor during the soldering, so that a self-alignment function of 
naturally locating the resistor substantially at a predetermined position 
may be exhibited. Also, in the illustrated embodiment, the rear surface 
electrode section 19c is formed into a configuration which permits it to 
fully surround the other opening of the recess 7. Such a configuration of 
the rear surface electrode section 19c prevents breakage of the corner of 
the recess 7 during manufacturing of the resistor. It is a matter of 
course that the contour of the rear surface electrode section 19c (a 
contour of a portion thereof except a portion thereof surrounding the 
opening of the recess 7) may be rectangular. 
In the illustrated embodiment, the resistor is formed into a medium size 
wherein the substrate 1 has a size of 3.2 mm.times.1.6 mm and a distance 
between centers of the recesses 7 adjacent to each other is defined to be 
0.8 mm. 
Now, manufacturing of the chip-like network resistor of the illustrated 
embodiment thus constructed will be described hereinafter with reference 
to FIGS. 4 to 7. First of all, a large-sized insulating substrate 30 made 
of a ceramic material is provided which is formed on at least a front 
surface thereof with lattice-like separation grooves constituted of a 
plurality of longitudinal grooves 31 and a plurality of lateral grooves 33 
and provided with a plurality of through-holes 35 of a circular shape in 
cross section. The through-holes 35 each are arranged along a portion of 
the lateral groove 33 positioned between each adjacent two of the 
longitudinal grooves 31. Formation of the grooves 31 and 33 and 
through-holes 35 may be carried out during manufacturing of the 
large-sized insulating substrate 30. Also, the large-sized insulating 
substrate 30 may be formed on a rear surface thereof with longitudinal and 
lateral grooves in a manner to correspond to the longitudinal and lateral 
grooves 31 and 33 formed on the front surface, respectively. 
Then, as shown in FIG. 4, a plurality of the thick-film electrodes 9 are 
formed on a plurality of regions 37 of the front surface of the 
large-sized insulating substrate 30 in a manner to be in proximity to the 
through-holes 35, respectively. The regions 37 each are defined at a 
position interposed between each adjacent two of the lateral grooves 33 
and between each adjacent two of the longitudinal grooves 31. The 
thick-film electrodes 9 each are formed by screen printing. In the 
illustrated embodiment, the thick-film electrodes 9 are made of an Ag--Pd 
glass paste. A temperature at which the Ag--Pd glass paste is calcined is 
about 800.degree. C. Then, a plurality of resistance elements 11 are 
formed on each of the regions 37 in a manner to extend between each 
adjacent two of the thick-film electrodes 9 opposite to each other on the 
region 37. The resistance elements 11 are likewise formed by screen 
printing. In the illustrated embodiment, the resistance elements 11 are 
made of a ruthenium oxide glass paste for a resistance element. 
Then, the resistance elements 11 formed on each of the regions 37 are 
covered with a glass coating 13. The glass coating is likewise formed by 
screen printing. Thereafter, as shown in FIG. 5, a front surface electrode 
18a, an inner electrode 18b and a rear surface electrode (not shown) are 
formed of a thin metal film 18. Formation of the front surface electrode 
18a is carried out so as to fully surround a circumference or periphery of 
one of openings of each of the through-holes 35 and overlap each of the 
thick-film electrodes 9. The inner electrode 18b is formed so as to cover 
an inner surface of each of the through-holes 35. The rear surface 
electrode is formed so as to fully surround a circumference or periphery 
of the other opening of the through-hole 35. Formation of the electrodes 
is attained in such a manner that masks formed at portions thereof 
corresponding to the through-holes 35 with holes for formation of the 
front surface electrode 18a and rear surface electrode are respectively 
arranged on the front and rear surfaces of the substrate 1 and the 
substrate 1 is concurrently subject on both surfaces thereof to vapor 
deposition or sputtering of metal, to thereby form the thin metal film 18 
on each of exposed portions of the substrate 1. In the illustrated 
embodiment, the thin metal film 18 is formed of nickel-chromium alloy and 
copper into a thickness of 1,000 to 10,000 .ANG. by vapor deposition. 
After formation of the thin metal film 18, as shown in FIG. 6, a probe 
electrode 39 for measurement is inserted at a distal end thereof into each 
of the through-holes 35 arranged on both sides of one of the resistance 
elements 11, to thereby be contacted with the front surface electrode 18a 
and inner electrode 18b, resulting in a resistance of the resistance 
element 11 being measured. The probe electrode 39 for measurement is 
formed at the distal end thereof into a diameter which permits it to be 
inserted into the through-hole 35 and at a rear portion thereof into a 
diameter larger than a diameter of the through-hole 35. Formation of the 
probe electrode 39 into such dimensions facilitates positioning of the 
probe electrode 39. When the resistance measured is larger than a desired 
resistance, the resistance element 11 is subject to laser trimming, 
resulting in the resistance being adjusted to a desired level. In the 
illustrated embodiment, the resistance elements 11 are constructed so as 
to have a resistance set at the same level, so that the remaining 
resistance elements of the region 7 are likewise subject to the laser 
trimming. Of course, the resistance elements 11 of the remaining regions 
are likewise subject to the laser trimming. In FIG. 6, reference numeral 
41 designates a groove for the trimming. 
After the trimming, as shown in FIG. 7, either an additional glass coating 
or a resin coating acting as a protective coating 15 is formed on the 
glass coating 13 by screen printing. Then, the protective coating 15 is 
formed thereon with the numeral of 103 for display using an ink for 
display. Thereafter, the large-sized insulating substrate 30 is divided 
into a plurality of chip-like elements along the longitudinal grooves 31 
and lateral grooved 33. This causes each of the thin metal films 18 to be 
cut into two, resulting in the chip-like elements which have the thin 
metal film electrode layer 19 formed in the recess 7 being obtained. Then, 
the nickel plated layer 21 (FIG. 2) is first formed on an electrode 
section (an exposed portion of the thick-film electrode 9 and the thin 
metal film electrode layer 19) of each of the chip-like elements and then 
the solder plated layer 23 (FIG. 2) is formed on the nickel plated layer 
21. The nickel plated layer 21 and solder plated layer 23 each are formed 
into a thickness of about 1 to 10 .mu.m by electroless plating or 
electroplating. 
Manufacturing of the chip-like network resistor in such a manner as 
described above permits a resistance to be measured using the thin metal 
film 18 as an electrode for measurement, to thereby increase an area of 
the electrode for measurement as compared with the prior art, so that 
measurement of the resistance may be facilitated while reducing an error 
in the measurement. 
In the illustrated embodiment, the thick-film electrode 9 is formed at the 
end edge of the portion 9a thereof facing the recess 7 into the arcuate 
shape in conformity to the opening of the recess 7. In genera, printing 
necessarily causes misregistration in printing; so that if the thick-film 
electrode is printed while being deviated from a desired position as 
indicated at broken lines in FIG. 9A, the conductive paste for the 
thick-film electrode 9 is caused to flow along the lateral groove when an 
end of the thick-film electrode overlaps the lateral groove. This leads to 
formation of an unnecessary electrode extension 10, resulting in a 
distance between the terminal electrodes adjacent to each other being 
reduced. Also, it causes a part of the conductive paste for the thick-film 
electrode 9 to flow into the recess 7. Such flowing of the conductive 
paste causes it to adhere to a mask used for formation of the thick-film 
electrode 9, to thereby hinder the subsequent operation of printing the 
thick-film electrode. An influence due to such misregistration in printing 
is increased with a reduction in size of the resistor. Thus, such a 
configuration of the thick-film electrode 9 as shown in FIG. 1 is not 
suitable for manufacturing of a small-sized resistor wherein, for example, 
the substrate 1 is as small as 2.0 mm.times.1.0 mm or less in size and a 
distance between centers of the recesses 7 adjacent to each other is as 
small as 0.5 mm or less. Thus, a thick-film electrode 9' is positioned 
inwardly of the recess 7 in the width direction of the substrate 1 and the 
thick-film electrode 9' is so formed that an end edge 9'A thereof facing 
the recess 7 substantially straightly extends along the end edge of the 
end 5 of the substrate 1. Such construction minimizes intrusion of the 
conductive paste into the recess 7 irrespective of some misregistration in 
printing during formation of the thick-film electrode and prevents a 
reduction in distance between the terminal electrodes. 
INDUSTRIAL APPLICABILITY 
The present invention permits all ends of one opening of the side surface 
electrode sections each covering the inner surface of the recess to be 
connected to the front surface electrode, to thereby prevent a substantial 
variation in resistance of the terminal electrodes. Also, a configuration 
which permits the one open end of the recess to be fully surrounded 
permits the front surface electrode section to act as a reinforcing member 
for increasing mechanical strength of the corner of the recess, to thereby 
prevent breakage of the corner during cutting of the large-sized 
insulating substrate. Further, formation of the thick-film electrode into 
a specific shape prevents a variation in distance between the terminal 
electrodes or a reduction of the distance. 
Further, the method of the present invention is so constructed that the 
thin metal film is formed into the electrode with respect to the 
through-hole after formation of the resistance element and is used as an 
electrode for measuring a resistance thereof. This increases an area of 
the electrode for measurement, to thereby facilitate measurement of the 
resistance and minimize an error in the measurement.