JPH10144501A - Chip resistor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize low resistance and low TCR (temperature coefficient) characteristics, and in addition, high precision and high reliability, in a chip resistance used for a circuit part of various electrical equipment. SOLUTION: This chip resistor comprises a substrate 1, a resistance layer 3 of copper/nickel alloy formed at least on one side of the substrate 1, upper surface electrode layers 2 which are formed on both end parts of the resistance layer 3, respectively, so as to be brought into surface-contact with the top surface, and an end surface electrode layer 5 provided so as to cover the top surface electrode layer 2. In particular, since joint of the resistance layer 3 and the top. surface electrode layer 5 is metal joint, no such impurity affecting on characteristics exists on an interface between them, thereby the chip resistor of excellent heat-resisting property, low resistance and low TCR characteristics is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip resistor widely used in electronic circuits, and more particularly to a chip resistor having low resistance and low TCR characteristics and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, demands for small electronic devices, such as mobile phones, movies, and notebook personal computers, have been increasing, and in the future, the miniaturization and high performance of these electronic devices will be used. It is no exaggeration to say that it depends on the miniaturization and high performance of chip-type electronic components. As a thick film resistor, a composition mainly composed of ruthenium oxide and its complex oxide, bismuth ruthenate or lead ruthenate, is known (for example, Japanese Patent Publication No. 58-37963).
), And are used in various fields.

An example of a conventional method for manufacturing a chip resistor will be described with reference to the drawings. FIG. 12 is a perspective view showing an example of the structure of a conventional square chip resistor, and FIG. 13 is a cross-sectional view taken along the line AA 'in FIG. In general, a method of manufacturing a square chip resistor of this kind is as follows. First, an upper electrode 11 is formed on an upper surface of a chip-shaped alumina substrate 10 made of 96% alumina. The resistor 12 is formed so as to be connected to the upper electrode, and a protective film 14 made of lead borosilicate glass is formed so as to completely cover the resistor 12. Generally, the protective film 14 is formed by forming a pattern by screen printing and then firing at a high temperature of 500 to 800 ° C.

Next, an end electrode 13 made of an Ag-based thick film is formed on the end surface of the alumina substrate 10 so as to connect to the upper electrode 11. At this time, the end electrode 13 generally has a temperature of about 600 ° C. It is formed by firing at a high temperature.
Finally, in order to ensure reliability when soldering, a Ni plating film 15 is formed by electroplating so as to cover the end face electrodes 13, and a solder plating film 16 is formed so as to cover the Ni plating film 15. To obtain a square chip resistor.

In a chip resistor manufactured by the above-described manufacturing method, generally, a thick film glaze resistor material containing ruthenium oxide as a main component is used as conductive particles serving as a resistor. In a resistor material consisting of only a resistor, a temperature coefficient of resistance (hereinafter, referred to as TCR) indicating a temperature change in resistance value becomes large. Therefore, adding a TCR adjusting material such as a metal oxide to ± 50 ppm
It was necessary to use a value as low as about / ° C.

However, when such a resistor material is used, it is difficult to form a chip resistor having a low resistance value of 1 Ω or less due to the high specific resistance of ruthenium oxide. Therefore, as a low resistance material of 1Ω or less, J
A chip resistor using a copper / nickel alloy having a small temperature coefficient of resistance as described in IS C2521 or C2532 has been proposed.

That is, a structure in which this alloy material is processed into a foil or plate shape and attached on an alumina substrate, or a resistor paste obtained by kneading copper powder, nickel powder and glass frit with an organic vehicle is printed on the alumina substrate. After that, a structure in which an alloy film is formed by firing in an inert atmosphere has been proposed (JP-A-2-308).
501, JP-A-3-270104).

[0008]

However, in the former case, the method of processing an alloy foil or an alloy plate has a limit as the shape of a chip part is increasingly reduced in size, and trimming is performed by laser. Can not be used,
Polishing and the like have limitations and are also disadvantageous in cost as compared with the printing method, so that they are not very excellent in mass productivity.

In the latter case, glass is used for adhesion between the resistor film and the substrate and for adjusting the resistance value, and contains a lot of components other than copper and nickel.
In addition to being different from the physical properties of nickel alloys, the glass component had a problem that it was difficult to obtain stable resistance value characteristics because the diffusion behavior in the metal component and the interface to the sintered particles differed depending on the firing conditions. .

Further, in the paste method using copper or nickel powder, since the characteristics of the terminal electrode of the power supply portion and the structure of the resistor / electrode interface greatly influence the characteristics of the resistor, the resistance value is limited to 100 mΩ. It was a limit, and it was difficult to realize a lower resistance value.

[0011] As described above, in recent years, the shape of chip resistors has become increasingly smaller, while the demand for chip resistors having low resistance and low TCR characteristics used for current detection of electronic circuits and the like has been increasing. There is a growing demand for chip resistors that satisfy not only low resistance and low TCR characteristics, but also high accuracy and high reliability, in view of the performance of the applications to be used.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and meets the above-mentioned demands. The present invention has a low-resistance and low-TCR characteristic of 1 Ω or less, particularly 100 mΩ or less, and a highly reliable chip resistor and its manufacture. The aim is to provide a method.

[0013]

The present invention comprises an insulating substrate,
A resistance layer made of a copper / nickel alloy formed on at least one surface of the insulating substrate, a pair of upper electrode layers formed so as to contact both ends of the resistance layer from the upper surface, and the upper electrode layer A chip resistor having a pair of end surface electrodes formed at both ends of the insulating substrate so as to cover at least a part of the insulating substrate. In particular, since the bonding between the resistance layer and the upper electrode layer is performed by metal bonding The interface is free from impurities that affect the characteristics, and has low resistance and low TC.
A chip resistor having R characteristics and excellent heat resistance can be obtained.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a schematic sectional view of a chip resistor according to a first embodiment of the present invention. In the figure, 3
Denotes a resistive layer, which is printed on one side of a rectangular insulating substrate (hereinafter simply referred to as a substrate) 1 by a thick film technique such as screen printing using a resistor paste having an alloy composition as shown in (Table 1). Has formed. Next, an upper surface electrode layer 2 is formed by printing in the same manner as the resistance layer 3 so as to be in surface contact with the resistance layer 3 at both ends facing the substrate 1, and the resistance layer 3 and the upper electrode layer 2 are neutralized. Simultaneous firing is performed in an atmosphere or a reducing atmosphere. Thereafter, a protective film layer 4 is formed so as to cover a part of the resistance layer 3, and a pair of opposite ends of the substrate 1 are U-shaped and not covered with the protection film layer 4 of the resistance layer 3. The end face electrode layer 5 is formed in the portion. Further, a Ni plating film 6 covering the end face electrode layer 5 is formed, and a solder plating film 7 is formed on the Ni plating film 6.

Hereinafter, a method of manufacturing a chip resistor will be described in detail. As the resistor paste, copper / nickel alloy powder (atomized powder having an average particle diameter of 5 μm) was used, and a mixed powder to which glass frit was added was used as an inorganic composition. As the glass frit, lead borosilicate glass was added at a ratio of 5% by weight to the metal powder, and the vehicle component used was a solution in which ethyl cellulose as an organic binder was dissolved in terpineol, and this was used as an organic vehicle composition. did. These inorganic composition and organic vehicle composition were kneaded with a three-roll mill to obtain a resistor paste.

Next, copper powder (average particle diameter: 2 μm) or silver powder (average particle diameter: 5 μm) is used as the upper electrode paste, and the vehicle component is obtained by dissolving ethyl cellulose as an organic binder with terpineol. Was used as an organic vehicle composition. These inorganic composition and organic vehicle composition were kneaded with a three-roll mill to obtain an upper electrode paste.

The resistor paste prepared as described above is printed on a substrate 1 (96% alumina substrate) with a resistor plate by using a screen plate.
After drying for 0 minutes, the upper electrode paste was applied to the upper surface of the resistor pattern using a screen plate as shown in FIG.
And printed at a temperature of 100 ° C. for 10 minutes. Next, the resistor 1 and the upper electrode layer 2 are simultaneously formed by simultaneously firing the resistor and the electrode in a profile that can be fired in a nitrogen atmosphere in the substrate 1. After that, a protective film layer 4 was formed by screen printing of an epoxy resin as a protective film of the resistance layer 3, and the resin was cured at 160 ° C. for 30 minutes. The resistance value, the temperature coefficient (TCR) of the resistance value, and the reliability (high-temperature storage test, thermal shock test) of the obtained resistor element were evaluated.

As a comparative example, after forming a copper electrode or a silver electrode containing glass frit as the upper electrode 11 so as to have a structure as shown in FIG. 13, an alloy powder, glass and an organic vehicle are pasted in the same manner as described above. Is printed on an alumina substrate 10 (96% alumina substrate).
After drying at a temperature of 00 ° C. for 10 minutes, the resistor was fired by heating under a firing condition shown in (Table 1) in an N ₂ atmosphere.

Next, a method of evaluating the fired resistor will be described. Resistance value is 25 ± 2 ° C and 65 ± 10% humidity.
After leaving it to stand in an RH atmosphere for 30 minutes or more, it was determined by a four-terminal method. In addition, the TCR characteristics were as follows. After placing the resistor in a thermostat and allowing the sample to stand
The resistance value at 5 ° C. was measured and the rate of change was determined.

The thermal shock test, which is a reliability evaluation item, is performed in two test tanks (−45 ° C.,
+ 150 ° C.), and immediately after being held in one test chamber for 30 minutes, a test that is exposed to the other test chamber for 30 minutes is performed.
The rate of change of the resistance value after repeating 0 cycles was evaluated. The high-temperature storage test was carried out in a test tank maintained at 150 ° C.
The resistance change rate after standing for 00 hours was evaluated.

The crystal structure of the cross section of the alloy layer of the manufactured resistor was clarified by using an X-ray diffractometer.

[0022]

[Table 1]

From the results shown in Table 1, the resistance film of the comparative example manufactured with the conventional structure can be connected to the upper electrode with high accuracy.
It can be seen that the quality as a resistor requiring high reliability is insufficient. A cross-sectional observation of the film quality at that time showed that many glass frit and voids were observed at the interface between the resistor 12 and the upper electrode 11, indicating that densification by sintering was not sufficiently advanced.

On the other hand, the interface between the resistive layer 3 and the upper electrode layer 2 produced by the method of the present invention does not contain any glass frit, so that no impurities are interposed therebetween, and the upper electrode layer 2 and the resistive layer 3 are simultaneously sintered. It has been found that a crystal structure having no clear interface connected by metal diffusion with the metal has been realized. This means that copper or silver diffuses into the copper / nickel alloy layer, which is the resistive layer, due to simultaneous sintering, so that a diffusion layer without a clear interface shows excellent thermal stability in terms of reliability. I think that the. Analysis of the sintered metal film with an X-ray diffractometer revealed that a uniform copper / nickel alloy layer was formed. Further, when the film quality was observed with a scanning electron microscope, it was found that a dense sintered film having almost no voids was obtained.

Next, a specific method of manufacturing the chip resistor will be described with reference to the manufacturing process diagram of FIG.

The resistor composition in which the ratio of the copper / nickel alloy powder and the glass frit was changed was mixed by a three-roll mill to prepare a resistor paste having a viscosity of 200 to 250,000 Pascal-second (Step 1).

This paste was screen-printed on an alumina substrate and dried (resistor size: 2 mm square, dry film thickness: 40 μm)
m) to form a resistor (Step 2), and kneading copper powder (average particle diameter: 2 μm) or silver powder (average particle diameter: 5 μm) and an organic vehicle as a top electrode layer with a three-roll mill, and having a viscosity of 20 to 20 μm. An electrode paste of 250,000 Pascal-second was prepared (Step 3). Using this electrode paste, screen printing and dry formation (dry film thickness: 30 μm) are performed so as to make a structure in which the surface of the resistor is brought into surface contact as shown in FIG.
m) (Step 4). Then, under nitrogen atmosphere, 900
The resistive layer 3 and the upper electrode layer 2 were prepared by holding at 10 ° C. for 10 minutes and firing (Step 5).

Next, a commercially available copper electrode paste was applied as an end face electrode to a thickness of about 50 to 100 μm on the end face and baked at 800 ° C. for 10 minutes in a nitrogen atmosphere to form an end face electrode layer 5. (Step 6). Thereafter, the resistance layer 3 is cut and trimmed by a YAG laser (Steel).
p7), followed by an epoxy resin paste (St
ep8) is printed and cured on the resistance layer (cured film thickness: 40 μm,
The film was cured at 150 ° C. for 30 minutes to form a protective film layer 4 (Step 9).

Thereafter, a design was implemented by treating the end faces with Ni plating 6 and solder plating 7 to form chip components (Steps 10 and 11), thereby improving the solder wettability during mounting.

As is clear from Table 1, the resistor obtained by such a manufacturing method has sufficient reliability in heat resistance such as high temperature storage and thermal shock test. The reason for the stability at high temperatures is that the metal layer does not have an interface clearly, it has an alloyed diffusion layer, and the upper electrode layer does not contain glass frit, which is an impurity. A chip resistor excellent in heat resistance with TCR characteristics was realized.

Generally, by changing the copper / nickel alloy ratio, the temperature coefficient of resistance (TCR characteristic) becomes 40%.
Although it can be adjusted in the range of 0 to -200 ppm / ° C., in the first embodiment, 40 to −20 p.
pm / ° C., and the resistance was able to cover a low resistance value range of up to 10 mΩ. Moreover, the adhesive strength required for the resistor is also excellent. Further, in other reliability evaluations, the resistor had sufficient durability for practical use.

Although a resin paste is used as the protective film in this embodiment, it goes without saying that a similar effect can be obtained by using a commonly used glass paste.

(Embodiment 2) A resistor paste prepared using the alloy powder mixture ratio composition shown in (Table 2) and prepared in the same manner as in Embodiment 1 is shown in (Table 2). A chip resistor obtained by printing and firing in the firing atmosphere shown in the same manner as in Embodiment 1 will be described.

The chip resistor thus manufactured was evaluated for its resistance value, temperature coefficient of resistance (TCR), and reliability (high temperature exposure, thermal shock test).

As a comparative example, a screen plate was prepared by pasting alloy powder, glass frit, and an organic vehicle on a substrate 10 on which an upper electrode 11 as shown in FIG. 13 was formed as in the first embodiment. print Te, dried 10 minutes at a temperature of 100 ° C., 1000 under N ₂
The resistor was baked by heating to ° C. Thereafter, an end face electrode and a protective film were formed in the same manner as in the first embodiment to form a resistor.

The method for evaluating the resistor after firing is also described in the first embodiment.
Was determined in the same manner as in. The results are shown in (Table 2).

[0037]

[Table 2]

As is clear from Table 2, the interface between the resistive layer 3 and the upper electrode layer 2 manufactured by the method of the present embodiment has no intervening impurities, and the upper electrode layer 2 is formed by simultaneous sintering.
A crystal structure having no clear interface connected by metal diffusion between the resistive layer 3 and the resistive layer 3 can be realized. This means that having a diffusion layer without an interface by simultaneous sintering shows excellent thermal stability in terms of reliability. From these facts, it can be seen that a chip resistor having low resistance and low TCR characteristics and exhibiting excellent reliability characteristics can be obtained.

When a copper electrode is used as the upper electrode layer, if the firing temperature is in the range of 600 to 1000 ° C., the reproducibility of the resistance value and the temperature coefficient of resistance is good, and when the silver electrode is used. Has a firing temperature of 600 to 85
Within the range of 0 ° C., the reproducibility of the resistance value and the temperature coefficient of resistance is good. However, when a silver electrode is used, the alloying of silver and copper of the resistive layer occurs at a low temperature, so that the temperature cannot be raised to a very high temperature. Further, by firing in a reducing atmosphere rather than a nitrogen atmosphere, the firing resistance can be further reduced.

(Embodiment 3) FIG. 3 is a schematic sectional view of a chip resistor according to a third embodiment of the present invention. In this chip resistor, a lower surface electrode layer 8 is formed on one side of a rectangular substrate 1 by printing and firing on a pair of both ends facing the substrate by a thick film technique such as screen printing. Lower electrode layer 8
The electrode paste was prepared by adding copper or silver powder as metal powder and lead borosilicate glass as a glass frit by adding 3 wt% to the metal powder. Next, the resistor layer 3 is printed and formed on the lower electrode layer 8 as shown in FIG. 3 by a thick film technique such as screen printing using a resistor paste having an alloy composition shown in (Table 3). Next, the upper surface electrode layer 2 is formed by printing in the same manner as the resistance layer 3 so as to be in surface contact with the resistance layer 3 at a pair of opposite ends facing the substrate 1. The resistance layer 3 and the upper electrode layer 2 are formed by simultaneous firing in a neutral atmosphere or a reducing atmosphere. After that, the protection film and the end face electrode are formed by the same method as in the first embodiment.

The same evaluations as those of the first embodiment were performed on the resistance value, the temperature coefficient (TCR) of the resistance value, and the reliability (high-temperature storage test, thermal shock test) of the resulting chip resistor.

[0042]

[Table 3]

As is clear from Table 3, according to the third embodiment, the resistor has a very low resistance value and is very excellent in a long-term reliability test of thermal shock characteristics and heat resistance. And the reliability of various electrical properties is excellent.

As a comparative example, a resistor manufactured by a conventional method showed insufficient performance from the viewpoint of long-term reliability of heat resistance.

As described above, according to the first to third embodiments,
It has a low resistance value and low TCR characteristics that provide an electrode structure that is stable in heat resistance because it has an alloyed interface between the upper electrode layer and the resistance layer, and has long-term reliability of heat resistance. An advantageous effect is obtained that a high-precision chip resistor with extremely little change in resistance value is realized and the resistor can be manufactured at low cost.

The thick film resistor compositions according to the first to third embodiments have a high temperature (600 to 1000) in order to lower the resistance value.
C), and the glass frit is preferably a high melting point glass frit having a glass transition point of 450 to 800 ° C., particularly one or two or more of a lead borosilicate glass type and a zinc borosilicate glass type. In general, the temperature coefficient of resistance is preferably closer to zero. Therefore, a value of ± 400 ppm / ° C. has been selected from the viewpoints of performance, price, and the like. Obtained.

The material of the substrate is 600 to 100
Any material can be used as long as it can withstand a firing temperature of 0 ° C. For example, glass ceramic substrates can be widely used in addition to alumina, forsterite, mullite, and aluminum nitride.

(Embodiment 4) FIG. 4 is a schematic sectional view of a chip resistor according to a fourth embodiment of the present invention. In the figure, reference numeral 3 denotes a resistance layer, and a thick film such as screen printing is formed on both surfaces of a rectangular ceramic substrate (hereinafter simply referred to as a substrate) 1 by using a resistor paste having an alloy composition as shown in (Table 4). Printing is performed by a forming technique. Next, the upper surface electrode layer 2 is printed and formed on both ends of the resistance layer 3 in the same manner as the resistance layer 3 so as to make surface contact with the resistance layer 3, and at least a part of the upper surface electrode layer 2 is formed on both side surfaces of the substrate 1. A pair of U-shaped end face electrode layers 5 are formed so as to cover them, and these are simultaneously fired in a neutral atmosphere or a reducing atmosphere.

Hereinafter, a method for producing the resistor paste will be described. As the copper-nickel alloy powder, atomized powder having an average particle diameter of 2 μm was used, and a mixed powder obtained by adding glass thereto was used as an inorganic composition. In addition, as a vehicle, a solution obtained by dissolving ethyl cellulose as an organic binder with terpineol was used as an organic composition. The inorganic composition and the organic composition were kneaded with a three-roll mill to obtain a resistor paste for forming the resistor layer 3.

Next, a method for producing an electrode paste for forming the upper electrode layer 2 will be described. As the copper powder, a powder having an average particle diameter of 2 μm was used as an inorganic composition. In addition, as a vehicle, a solution obtained by dissolving ethyl cellulose as an organic binder with terpineol was used as an organic composition. These inorganic composition and organic composition were kneaded with a three-roll mill to obtain an electrode paste for the upper electrode layer 2.

Hereinafter, a method of manufacturing a chip resistor will be described. First, the resistive paste for the resistive layer 3 is applied to the substrate 1 (96
% Alumina substrate (6.4 x 3.2 mm)
Dry at a temperature of 00 ° C. for 10 minutes. Next, the electrode paste for the upper electrode layer 2 was screen-printed and dried so as to have a structure in which the electrode paste was in surface contact with the upper surface of the resistance layer 3. Then, a commercially available copper electrode paste is applied as the end face electrode layer 5 to the end face so as to have a thickness of about 50 to 100 μm, and then these are baked at 900 ° C. for 10 minutes in a nitrogen atmosphere to obtain a chip as shown in FIG. A resistor was made.

Hereinafter, a method of evaluating a chip resistor will be described. 3. The electrode distance between the upper electrode layers 2 of the chip resistor is set to 4.
The thickness of the fired resistor was set to 2.5 mm, the probe was fixed to the upper electrode layer 2, and the inter-terminal resistance was determined by a four-terminal method. The TCR characteristics were obtained by placing the chip resistor in a thermostat, measuring the resistance values at 25 ° C. and 125 ° C., and calculating the rate of change. The resistance change during high-temperature storage was determined by coating the fired resistor with a resin as protective layer 11 as shown in FIGS. 10 and 11 (layer thickness: about 50 μm) and leaving it at 160 ° C. for 1000 hours. .

The structure of the cross section of the manufactured chip resistor was clarified using a scanning electron microscope, an electron beam microanalyzer, and an X-ray micro diffractometer.

The results are shown in (Table 4).

[0055]

[Table 4]

As is clear from Table 4, according to the chip resistor of the present embodiment, a chip resistor having a low resistance value, a low TCR and a high reliability can be obtained by forming a resistance layer on both sides. Moreover, since the fired particle diameter of the resistor layer is 40 μm or less and the layer thickness is 30 μm or less, trimming by a YAG laser can be performed. In general, laser trimming cannot be performed for metal foil or metal wire because the laser energy is reflected, and trimming such as sand blasting cannot be performed easily and with high precision. A form of chip resistor is very effective.

(Embodiment 5) FIG. 5 is a schematic sectional view of a chip resistor according to a fifth embodiment of the present invention. In the drawing, 3 is a resistance layer, and 8 is a metal foil 8 (6.4 × 3.2 mm, thickness = 0.04 mm) having an alloy composition as shown in (Table 5).

The production of the resistor paste for the resistance layer 3 was performed in the same manner as in the fourth embodiment.

Hereinafter, a method of manufacturing a chip resistor will be described. First, a resistor paste for forming the resistor layer 3 is printed on the metal foil 8, dried at a temperature of 100 ° C. for 10 minutes, and baked in a nitrogen atmosphere at 900 ° C. for 10 minutes to obtain a chip resistor as shown in FIG. A vessel was made.

The evaluation method of the chip resistor is the same as that of the fourth embodiment, and the results are shown in Table 5.

[0061]

[Table 5]

(Embodiment 6) FIG. 6 is a schematic sectional view of a chip resistor according to a sixth embodiment of the present invention. In the figure, reference numeral 3 denotes a resistance layer, 8 denotes a metal foil as shown in (Table 6), and screen printing is performed on both surfaces of the rectangular substrate 1 using a resistor paste having an alloy composition as shown in (Table 6). Printing is performed by a thick film forming technique such as that described above. next,
The upper electrode layer 2 is printed and formed on both ends of the resistance layer 3 in the same manner as the resistance layer 3 so as to be in surface contact with the resistance layer 3, and at least both sides of the substrate 1 cover at least a part of the upper electrode layer 2. Thus, a pair of U-shaped end face electrode layers 5 are formed, and these are simultaneously fired in a neutral atmosphere or a reducing atmosphere.

The preparation of the resistor paste for the resistance layer 3 and the preparation of the electrode paste for the upper electrode layer 2 were performed in the same manner as in the fourth embodiment.

Hereinafter, a method of manufacturing a chip resistor will be described. First, the substrate 1 (96% alumina substrate 6.4 × 3.2
mm) on a metal foil 8 (3.8 × 2.3 mm, thickness = 0.02)
mm) was fixed by bonding or the like, and a resistor paste for forming the resistor layer 3 was printed thereon and dried at a temperature of 100 ° C. for 10 minutes. Next, an electrode paste for forming the upper electrode layer 2 was screen-printed and dried so as to have a structure in which the electrode paste was in surface contact with the upper surface of the resistance layer 3. Next, a commercially available copper electrode paste was used as the end face electrode layer 5 to form a film having a thickness of about 50 to 100 μm on the end face.
And then apply them in a nitrogen atmosphere for 9 hours.
Baking was performed at 00 ° C. for 10 minutes to produce a chip resistor as shown in FIG.

The evaluation method of the chip resistor is the same as that of the fourth embodiment, and the results are shown in (Table 6).

[0066]

[Table 6]

(Embodiment 7) FIG. 7 is a schematic sectional view of a chip resistor according to a seventh embodiment of the present invention.

In this embodiment, a metal wire 9 as shown in (Table 7) is used instead of the metal foil 8 of the sixth embodiment.
Is shown, and the diameter of the metal wire 9 is 0.6.
mm, length = 3.8 mm, and is configured to fit into a slit (not shown) provided on the substrate 1.

The evaluation method of the chip resistor is performed in the same manner as in the fourth embodiment, and the results are shown in (Table 7).

[0070]

[Table 7]

(Eighth Embodiment) FIG. 8 is a schematic sectional view of a chip resistor according to an eighth embodiment of the present invention. In the figure, 3 is a resistance layer, 8 is a metal foil as shown in (Table 8), and the other side of the rectangular substrate 1 is (Table 8)
Are formed by a thick film forming technique such as screen printing using a resistor paste having an alloy composition as shown in FIG. Next, the upper electrode layer 2 is printed and formed on both ends of the resistance layer 3 in the same manner as the resistance layer 3 so as to make surface contact with the resistance layer 3.
A pair of U-shaped end face electrode layers 5 are formed so as to cover a part thereof, and these are simultaneously fired in a neutral atmosphere or a reducing atmosphere.

The production of the resistor paste for the resistance layer 3 and the production of the electrode paste for the upper electrode layer 2 were performed in the same manner as in the fourth embodiment.

A method for manufacturing a chip resistor will be described below. First, the substrate 1 (96% alumina substrate 6.4 × 3.2 m
m) on one side of a metal foil 8 (6.4 × 2.5 mm, thickness = 0.
1 mm) was fixed by bonding or the like, and a resistor paste for forming the resistor layer 3 was printed on the surface opposite to the metal foil 8 and dried at a temperature of 100 ° C. for 10 minutes. Next, an electrode paste for forming the upper electrode layer 2 was screen-printed and dried so as to have a structure in which the electrode paste was in surface contact with the upper surface of the resistance layer 3. Next, a commercially available copper electrode paste is applied as the end face electrode layer 5 to the end face so as to have a thickness of about 50 to 100 μm, and then these are baked in a nitrogen atmosphere at 900 ° C. for 10 minutes, as shown in FIG. A chip resistor was manufactured.

The evaluation method of the chip resistor is performed in the same manner as in the fourth embodiment, and the results are shown in (Table 8).

[0075]

[Table 8]

(Embodiment 9) FIG. 9 is a schematic sectional view of a chip resistor according to a ninth embodiment of the present invention. In the figure, 3 is a resistance layer, 9 is a metal wire as shown in (Table 9), and is screen-printed on both surfaces of the rectangular substrate 1 using a resistor paste having an alloy composition as shown in (Table 8). Printing is performed by a thick film forming technique such as that described above. next,
The upper surface electrode layer 2 is printed and formed on both ends of the resistance layer 3 in the same manner as the resistance layer 3 so as to be in surface contact with the resistance layer 3, and the upper surface electrode layers 2 provided on at least both surfaces on both sides of the substrate 1. A pair of U-shaped end face electrode layers 5 are formed so as to cover a part thereof, and these are simultaneously fired in a neutral atmosphere or a reducing atmosphere.

The preparation of the resistor paste for the resistance layer 3 and the preparation of the electrode paste for the upper electrode layer 2 were performed in the same manner as in the fourth embodiment.

Hereinafter, a method of manufacturing a chip resistor will be described. First, the substrate 1 (96% alumina substrate 6.4 × 3.2
A metal wire 9 (diameter = 0.6 mm, length = 3.8 mm) is inserted and fixed in a slit (not shown) provided on one surface of the metal wire 9). Next, a resistor paste for forming the resistor layer 3 was printed on both sides and dried at a temperature of 100 ° C. for 10 minutes. Next, the electrode paste for forming the upper electrode layer 2 is applied to both resistance layers 3.
Was formed by screen printing so as to have a structure in which it was in surface contact with the upper surface of the substrate, and dried. Then, a commercially available copper electrode paste is applied as the end face electrode layer 5 to the end face so as to have a film thickness of about 50 to 100 μm.
Baking was performed at 0 ° C. for 10 minutes to produce a chip resistor as shown in FIG.

The evaluation method of the chip resistor is performed in the same manner as in the fourth embodiment, and the results are shown in (Table 9).

[0080]

[Table 9]

In the fourth to ninth embodiments, the end face electrode layer 5
As an example, the conduction of the upper and lower resistors is taken,
It is also possible to form a low-resistance chip resistor by forming a through-hole or the like in the substrate 1 and burying a metal paste or metal to make it conductive. When a metal foil or a metal wire is used, the substrate 1 is provided with irregularities (slits), and
Forming a resistor by fixing a metal wire saves time and effort such as bonding, and also allows them to be securely fixed without using substances that affect the properties of the adhesive. is there.

Further, in this embodiment, an example of trimming with a YAG laser has been described, but it goes without saying that the same effect can be obtained by performing trimming with another laser. It has been experimentally found that the thickness may be formed in such a range that the laser can be trimmed, and it is particularly preferable that the calcined particle diameter is 40 μm or less and the layer thickness is 30 μm or less.

[0083]

As described above, according to the present invention, since the resistance layer and the upper electrode layer are bonded by metal bonding, no impurity affecting the characteristics is present at the interface.
Low resistance, making full use of the material properties of copper / nickel alloys,
A highly reliable chip resistor having low TCR characteristics and excellent heat resistance can be realized.

Further, the sintered particle diameter of the fired resistor layer was set to 30 μm.
m or less, and the film thickness is 40 μm or less, so that it is possible to perform trimming with a laser, and it is possible to perform trimming very easily and accurately compared to polishing by sandblasting or the like,
A very inexpensive and highly accurate chip resistor can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a chip resistor according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the embodiment.

FIG. 3 is a schematic sectional view of a chip resistor according to a third embodiment of the present invention.

FIG. 4 is a schematic sectional view of a chip resistor according to a fourth embodiment of the present invention.

FIG. 5 is a schematic sectional view of a chip resistor according to a fifth embodiment of the present invention.

FIG. 6 is a schematic sectional view of a chip resistor according to a sixth embodiment of the present invention.

FIG. 7 is a schematic sectional view of a chip resistor according to a seventh embodiment of the present invention.

FIG. 8 is a schematic sectional view of a chip resistor according to an eighth embodiment of the present invention.

FIG. 9 is a schematic sectional view of a chip resistor according to a ninth embodiment of the present invention.

FIG. 10 is a perspective view showing a state where a resin coating is applied as a protective layer to a chip resistor according to a fourth embodiment of the present invention.

FIG. 11 is a cutaway sectional view of the same part.

FIG. 12 is a perspective view showing a configuration of a conventional chip resistor.

FIG. 13 is a sectional view taken along line A-A ′ of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Upper electrode layer 3 Resistance layer 4 Protective film layer 5 Edge electrode layer 6 Ni plating film 7 Solder plating film 8 Lower electrode layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naotsugu Yoneda 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (20)

[Claims] 1. An insulating substrate, a resistive layer made of copper / nickel alloy powder and glass frit provided on at least one surface of the insulating substrate, and provided at both ends of the resistive layer so as to be in surface contact with each other from above. A pair of upper surface electrode layers, and a pair of end surface electrodes provided on both side surfaces of the insulating substrate so as to cover at least a part of the upper surface electrode layer, and the bonding between the resistance layer and the upper surface electrode layer is provided. A chip resistor, which is a metal junction. 2. The chip resistor according to claim 1, wherein the upper electrode layer has a lower resistance value than the resistance layer. 3. The chip resistor according to claim 2, wherein the upper electrode layer comprises a copper electrode or a silver electrode. 4. An insulating substrate, a pair of lower electrode layers provided on both ends of at least one surface of the insulating substrate, and a copper / nickel alloy powder and a glass frit provided to connect the pair of lower electrode layers. And a pair of upper surface electrode layers provided at both ends of the resistance layer facing the lower surface electrode layer so as to be in surface contact with each other,
A pair of end electrodes provided on both side surfaces of the insulating substrate so as to cover at least a part of the upper electrode layer, wherein a junction between the resistance layer and the upper electrode layer is a metal junction. Chip resistor. 5. The chip resistor according to claim 4, wherein the upper electrode layer and the lower electrode layer have lower resistance values than the resistance layer. 6. The chip resistor according to claim 4, wherein the upper electrode layer and the lower electrode layer are made of a copper electrode or a silver electrode. 7. A step of forming a resistive layer made of copper / nickel alloy powder and glass frit on at least one surface of an insulating substrate, and forming a pair of upper electrode layers so that both ends of the resistive layer are in surface contact with the upper surface, respectively. Forming and firing, and forming a pair of end surface electrodes on both side surfaces of the insulating substrate so as to cover at least a portion of the sintered upper surface electrode layer, A method for manufacturing a chip resistor, wherein the layer and the upper electrode layer are joined by metal joining. 8. The method according to claim 6, wherein the resistance layer and the upper electrode layer are formed in a nitrogen atmosphere or a reducing atmosphere containing hydrogen in a range of 600 to 1000.
The method for manufacturing a chip resistor according to claim 7, wherein the chip resistor is formed by sintering at a temperature of ° C. 9. A step of forming a pair of lower electrode layers on both ends of at least one surface of an insulating substrate, and forming a resistance layer made of copper / nickel alloy powder and glass frit so as to connect the pair of lower electrode layers. Forming a pair of upper electrode layers so as to be in surface contact with both ends of the resistive layer, respectively, from the upper surface, and sintering the insulating layer, and insulating the cover so as to cover at least a part of the sintered upper electrode layer. Forming a pair of end electrodes on both side surfaces of the substrate, wherein the sintered lower surface electrode layer and the resistance layer and the resistance layer and the upper surface electrode layer are respectively joined by metal joining. To manufacture chip resistors. 10. The resistive layer and the upper electrode layer are formed in a nitrogen atmosphere or a reducing atmosphere containing hydrogen in a range of 600 to 100.
The method for manufacturing a chip resistor according to claim 9, wherein the chip resistor is formed by sintering at a temperature of 0 ° C. 11. A fired resistor layer provided on both sides of a ceramic substrate and formed by sintering and made of at least copper / nickel alloy powder, and at least a part of each of both end portions of the fired resistor layer on both surfaces. And terminal electrodes provided on both side surfaces of the ceramic substrate so as to cover at least a part of each of both ends of the terminal electrode, and provided on at least one surface of the ceramic substrate. A chip resistor, wherein the sintered resistor layer has a sintered particle diameter of 30 μm or less and a film thickness of 40 μm or less. 12. A fired resistor layer comprising: a metal foil made of at least copper / nickel or nickel / chromium; and a fired resistor layer formed on the metal foil and formed by sintering made of at least copper / nickel. Of sintered particles of 30
A chip resistor having a thickness of 40 μm or less and a thickness of 40 μm or less. 13. A metal foil made of at least copper / nickel or nickel / chromium provided on at least one side of a ceramic substrate, and a sintered resistor layer made of at least copper nickel provided on the metal foil and formed by sintering. ,
A pair of terminal electrodes provided so as to cover at least a part of each of both ends of the fired resistor layer, and on both side surfaces of the ceramic substrate so as to cover at least a part of each of the both ends of the terminal electrode. Provided end face electrode, the sintered particle diameter of the fired resistor layer is 30μm or less,
A chip resistor having a thickness of 40 μm or less. 14. The chip resistor according to claim 13, wherein a metal wire made of at least copper / nickel or nickel / chromium is used instead of the metal foil. 15. A metal foil made of at least copper / nickel or nickel / chromium provided on one side of a ceramic substrate, and a sintered resistor layer made of sintered and made of at least copper / nickel provided on the other side. A pair of terminal electrodes provided so as to cover at least a part of each end of the fired resistor layer, at least a part of each end of the terminal electrode and a part of both ends of the metal foil. An end surface electrode provided on both side surfaces of the ceramic substrate so as to cover the ceramic substrate, wherein the sintered resistor layer has a sintered particle diameter of 30 μm or less and a film thickness of 40 μm or less. vessel. 16. A metal wire made of at least copper / nickel or nickel / chromium provided on one surface of a ceramic substrate, and a sintered wire made of at least copper / nickel provided on the other surface and the upper surface of said metal wire. The fired resistor layer, and terminal electrodes provided so as to cover at least a part of both ends of the fired resistor layers on both sides, and at least a part of each of both end parts of the terminal electrode. End electrodes provided on both side surfaces of the ceramic substrate, wherein at least one of the two fired resistor layers has a sintered particle diameter of 30 μm or less and a film thickness of 40 μm or less. Chip resistor. 17. The semiconductor device according to claim 11, wherein at least a part of the end face electrode is covered with a resin except for at least a part thereof.
16. The chip resistor according to any one of 16). 18. A step of forming a resistor layer made of at least copper / nickel alloy powder on both surfaces of a ceramic substrate, and a step of forming terminal electrodes so as to cover at least a part of both ends of the resistor layer. Forming an end face electrode on both sides of the ceramic substrate so as to cover at least a part of each of both end portions of the terminal electrode, firing the same, and trimming the fired resistor. A resistor layer provided on at least one side of the ceramic substrate, wherein the resistor layer has a thickness within a range in which laser trimming is possible. 19. A resistor layer made of at least copper / nickel is formed on a metal foil made of at least copper / nickel or nickel / chromium. When trimming is performed after firing, the thickness of the resistor layer is adjusted by laser. A method for manufacturing a chip resistor, wherein the chip resistor is formed within a thickness range in which trimming is possible. 20. A step of forming a metal foil or a metal wire made of at least copper / nickel or nickel / chromium on at least one surface of a ceramic substrate, and forming a resistor layer made of at least copper / nickel on the metal foil or the metal wire. Forming, and forming a pair of terminal electrodes so as to cover at least a part of both ends of the resistor layer,
Forming end electrodes on both side surfaces of the ceramic substrate so as to cover at least a part of both ends of each of the terminal electrodes and a part of both ends of the metal foil or the metal wire, and firing the same; Trimming the obtained resistor, wherein the thickness of the resistor layer provided on at least one surface of the ceramic substrate is formed in a thickness range that can be trimmed by laser. Production method.