JP4397279B2 - Resistive composition and resistor using the same - Google Patents

Description

  The present invention relates to, for example, a resistance composition used for a current detection resistor in a current detection circuit and the like, and a resistor using the composition.

  For applications such as current detection in electronic circuits such as devices and power supply circuits, there is an increasing demand for resistors having low resistance and low TCR (Temperature Coefficient of Resistance) characteristics. Such a resistor obtains a low resistance characteristic by using a resistor paste made of, for example, silver (Ag) -palladium (Pd) or copper (Cu) -nickel (Ni) (for example, Patent Document 1). , 2).

  On the other hand, Patent Document 3 discloses a copper conductor composition comprising copper powder, copper oxide, and a low-melting glass frit.

Japanese Patent Laid-Open No. 9-246007

JP 11-233302 A

JP 58-48987

  However, in the case of the resistor paste using the above-described copper-nickel as a conductive component, the thermal electromotive force for copper used for the electrode of the resistor using the paste is high (for example, 46 μV / K), which is the current. There is a problem that a desired characteristic (current detection accuracy) cannot be obtained due to an error in detection.

Furthermore, in the case of the conventional resistor paste made of copper-nickel, the resistivity is high (0.65 μΩm), and there is a problem that it cannot cope with the resistance value required in recent years. For example, when the blend of copper and nickel is 57/43, the sheet resistance value is 35 mΩ / □ and the TCR is 87 × 10 ⁻⁶ / K. When the copper-nickel composition is 90/10, the sheet resistance value is 15 mΩ / □, and the TCR is 1200 × 10 ⁻⁶ / K.

The present invention has been made in view of the above-described problems, and its object is to have a low copper thermoelectromotive force and to have a volume resistivity equivalent to or lower than that of the conventional one. Thus, it is to provide a resistance composition having a low TCR (for example, within ± 100 × 10 ⁻⁶ / K) and a resistor using the same.

As a means for achieving this object and solving the above-mentioned problems, for example, the following configuration is provided. That is, the current detection resistor according to the present invention includes an electrically insulating substrate, a resistance layer formed on the substrate, and a pair of electrodes disposed on both ends of the resistance layer and in electrical contact with the resistance layer. The pair of electrodes is made of copper, and the resistive layer includes 84 to 88 wt% copper, 11 to 13 wt% manganese, and 1 to 3 wt% iron as metal components, It is characterized by containing glass powder and / or copper oxide powder in an amount not exceeding 10 parts by weight per 100 parts by weight of the metal component .

The resistance layer includes copper oxide, and the copper oxide is made of either CuO or Cu ₂ O.

Furthermore, as another means for solving the above-described problem, for example, the following configuration is provided. That is, a method for manufacturing a current detecting resistor according to the present invention includes a step of preparing an electrically insulating substrate having a size corresponding to a plurality of current detecting resistors, and a copper paste on the electrically insulating substrate. A step of printing to form an electrode; 84 to 88 wt% copper, 11 to 13 wt% manganese, and 1 to 3 wt% iron as metal components; A resistor paste containing 10 to 15 parts by weight of a vehicle and / or copper oxide powder in a range not exceeding 10 parts by weight, and a part of the resistor paste comprising: Printing the resistor so as to overlap the electrode, forming a resistor, forming a protective film for protecting the resistor, and dividing the substrate after forming the protective film into individual pieces. Characteristic To.

  According to the present invention, it is possible to produce a resistance composition and a resistor having a low resistance value, a low TCR, and a low thermoelectric power against copper.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings and tables. The resistor paste according to the present embodiment includes, for example, a conductive metal mixed powder composed of copper powder, manganese powder, and iron powder, and glass powder mixed with the metal mixed powder. A resistor paste, which is a resistor composition, is prepared from a copper oxide powder (copper oxide powder) and a vehicle made of a resin and / or a solvent, and a resistor is manufactured using the resistor paste. .

Mixed metal powder of the resistor paste, as the metal component, and 11 to 13 wt% of manganese (Mn), were mixed with 1 to 3 wt% of iron (Fe), the remaining wt% of copper (Cu) It becomes. Moreover, 0-10 weight part of glass powders mentioned above and 0-10 weight part of copper oxide powder are included with respect to the whole quantity (100 weight part) of these metal components, for example.

  The glass powder is used for the purpose of physical adhesion among the components to be adhered to the substrate, which will be described later. Here, when the proportion exceeds 10 parts by weight, the resistivity increases. In addition, the copper oxide powder is used for the purpose of chemical adhesion among the components in close contact with the substrate, and when the proportion exceeds 10 parts by weight, the resistance film becomes porous, Smoothness is impaired.

  The resistor paste according to the present embodiment includes at least one of glass powder and copper oxide powder as these adhesion components. However, when the combination of the glass powder and the copper oxide powder is 0 part by weight, the adhesion to the substrate is lost.

  Furthermore, in the present embodiment, in order to paste the resistor, for example, it is preferable to mix 10 to 15 parts by weight of a vehicle containing a resin and a solvent so that the resistor paste has a viscosity suitable for printing. Depending on the printability, the blending amount may exceed this range.

  In the resistor paste according to the present embodiment, in addition to a metal mixed powder obtained by mixing copper, manganese and iron powders, a metal powder containing an alloy powder of these metals is used as a conductive metal. It may be used as a mixed powder, or both of these powders may be used. In any case, if the finally added total mixing ratio of copper, manganese and iron is the above ratio, desired characteristics can be obtained in the resistance value and TCR as a resistor paste, and the thermoelectric power against copper. .

  The metal powder (copper, manganese, iron powder) that is a conductive metal mixed material of the resistor paste preferably has a particle size in a range that can be used in a screen printing method on a substrate. The particle diameter is preferably in the range of 0.1 μm to 20 μm.

  The glass powder used for the resistor paste according to this embodiment has adhesion with an insulating substrate that forms a resistor layer with the resistor paste and various stability required as a resistor. In addition, from the viewpoint of workability, a borosilicate glass having a softening point of 500 to 1000 ° C. and having acid resistance and water resistance is preferable.

  Therefore, for example, borosilicate barium glass, borosilicate calcium glass, borosilicate barium calcium glass, borosilicate zinc glass, or zinc borosilicate glass can be used as the glass powder. Moreover, it is preferable that the particle size of glass powder exists in the range which can be used by screen printing, for example, the particle size of 0.1 micrometer-20 micrometers is preferable, and the average particle diameter of 2 micrometers or less is especially more preferable.

In the present embodiment, the copper oxide of the copper oxide powder is a material having adhesiveness with an insulating substrate that forms a resistor layer with a resistor paste, and various stability required as a resistor. For example, both CuO (cupric oxide) and Cu ₂ O (cuprous oxide) can be used. The particle size of the copper oxide powder is preferably in a range that can be used in screen printing. For example, the particle size is preferably 0.1 μm to 20 μm, and more preferably the average particle size is 2 μm or less. preferable.

  On the other hand, in the resistor paste according to the present embodiment, examples of the resin used for the vehicle including the resin and the solvent include, for example, cellulose resins, acrylic resins, alkyd resins, etc., alone or in combination. Can be used. More specifically, for example, ethyl cellulose, ethyl acrylate, butyl acrylate, ethyl methacrylate, butyl methacrylate and the like can be mentioned.

  In addition, as a solvent used in a vehicle composed of a resin and a solvent in a resistor paste, for example, a terpene solvent, an ester alcohol solvent, an aromatic hydrocarbon solvent, an ester solvent, etc., alone or in combination Can be used. More specifically, for example, terpineol, dihydroterpineol, 2,2,4-trimethyl-1,3-pentanediol, texanol, xylene, isopropylbenzene, toluene, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol acetate A monobutyl ether etc. can be mentioned.

  The vehicle configuration is not limited to the above resin and solvent, and various additives may be added to improve the characteristics of the resistor paste.

  FIG. 1 shows a manufacturing process of a resistor paste which is a resistor composition according to this embodiment. In step S1 of FIG. 1, metal powder as a conductive metal mixed material of the resistor paste is mixed. Here, copper, manganese, and iron (Cu—Mn—Fe) powders are mixed.

  In addition, as the conductive metal mixed material of the resistor paste, copper, manganese, and metal mixed powder composed of copper powder, manganese powder and iron powder, and alloy powder composed of copper, manganese and iron, and The metal powder may be composed of a metal mixed powder made of iron. Further, as the conductive metal mixed material of the resistor paste, copper, manganese, and metal mixed powder composed of copper powder, manganese powder and iron powder, or alloy powder composed of copper, manganese and iron, and The metal powder may be composed of a metal mixed powder made of iron.

Specific compounding ratio of the metal powders, manganese powder (e.g., average particle size 10 [mu] m) and 11 to 13 wt%, iron powder (e.g., an average particle diameter of 2 [mu] m) and 1 to 3 wt%, copper powder (For example, an average particle diameter of 1 μm) is mixed in a ratio of the remaining wt% .

  In step S2, glass powder and / or copper oxide powder are mixed with the metal mixed powder mixed in step S1. Here, for example, 0 to 10 parts by weight of glass powder and 0 to 10 parts by weight of copper oxide powder are mixed with respect to the total amount of metal powder of copper, manganese, and iron (Cu—Mn—Fe). .

  In step S3, the vehicle is mixed. That is, it consists of an organic resin and a solvent with respect to the total amount obtained by mixing the above metal mixed powder of copper, manganese and iron (Cu—Mn—Fe), glass powder and / or copper oxide powder. A resistor paste is prepared by adding 10 to 15 parts by weight of a vehicle (for example, a texanol solution containing 2.5% by weight of ethyl cellulose) and kneading with three rolls.

In this embodiment, the obtained resistor paste is printed on a copper electrode previously formed on an alumina substrate of 96 wt% alumina, dried, and then nitrogen (N ₂ ) In the atmosphere, for example, the resistor was manufactured by baking at 980 ° C. for 10 minutes.

  Table 1 shows the characteristics of the resistor obtained by firing as described above. In this embodiment, a metal mixed powder of copper, manganese, and iron (Cu—Mn—Fe) is mixed at a blending ratio shown in Table 1 (unit: weight percent (wt%)), and glass powder is mixed therewith. The body (5 weight percent) and copper oxide powder (5 weight percent) were added and mixed well, and further the vehicle was added to make a resistor paste.

  That is, Table 1 shows resistivity values of the respective resistors (sample Nos. 1 to 10) obtained by firing the resistor paste described above and comparative examples (resistor paste made of copper-nickel). (ΜΩm), resistance temperature coefficient (TCR), and thermoelectric power against copper (μV / K). These resistivity and the like were measured at 25 ° C. and 125 ° C.

Here, an example (resistor of sample No. 6 in Table 1) of the resistor paste according to the present embodiment will be described. In the resistor paste of the resistor according to this example, 86 wt% of copper powder, 12 wt% of manganese powder, and 2 wt% of iron powder were measured and mixed, and copper oxide powder 5 was mixed with the mixed powder. It is a resistor paste obtained by adding 5 parts by weight of glass powder and 5 parts by weight of glass powder, thoroughly mixing them, and further adding 12 parts by weight of vehicle to this mixed powder and kneading with three rolls.

About the obtained resistor paste, the above-described firing was performed to produce a resistor, and the resistance value of the resistor was measured to determine the resistivity, the temperature coefficient of resistance, and the thermoelectric power against copper. In the case of the resistor of the example (sample No. 6), the resistivity was 0.65 μΩm, the temperature coefficient of resistance was 47 × 10 ⁻⁶ / K, and the thermoelectric power against copper was 2 μV / K.

In addition, the following resistors were produced as comparative examples. Specifically, 57.0 wt% of copper powder and 43.0 wt% of nickel powder were measured, and 5 parts by weight of copper oxide powder and 5 parts by weight of glass powder were added to the mixed powder, Mixed. Further, 12 parts by weight of a vehicle was added to the mixed powder, and kneaded with three rolls to obtain a resistor paste. And about the resistor obtained by baking the resistor paste which consists of such copper-nickel, when the characteristic was measured, a resistivity was 0.70 microhm and a resistance temperature coefficient was 87x10 < ^-6 > / K, The copper electromotive force was 46 μV / K.

  FIG. 2 is a diagram showing the composition of the resistor according to the present embodiment. The numbers in the circles in FIG. It corresponds to each of 1 to 10, and plots the compounding ratio of Cu / Mn / Fe for each sample. Further, in FIG. 2, a preferable metal for obtaining a resistor having a desired low resistance value, low temperature coefficient of resistance, and copper electromotive force, in which the compounding ratio of Cu / Mn / Fe is within the range indicated by the thick line. The composition range of the component.

That is, the resistor in the portion exceeding the “preferable range” indicated by shading in FIG. 2 is a resistor made of a conventional resistor paste made of copper-nickel (see the comparative example described above). ) Or a resistivity temperature coefficient larger than a target value (± 100 × 10 ⁻⁶ / K or less), which is not appropriate.

  FIG. 3 shows a cross-sectional configuration of an example of a square chip resistor (hereinafter simply referred to as a chip resistor) using the resistor paste according to the present embodiment. In FIG. 3, a substrate 1 is a ceramic substrate (insulating base) having a predetermined size, for example, an electrically insulating ceramic substrate. On the substrate 1, the resistor paste formed by blending the above-described metal mixed powder is applied by, for example, screen printing and then baked to form the resistance layer 2.

  The upper part of the resistance layer 2 is covered and protected by the pre-glass 7. Further, a protective film 3 functioning as an insulating film is disposed on the pre-glass 7. Upper electrodes (surface electrodes) 4a and 4b that are in electrical contact with both ends of the substrate 1 and at both ends of the resistance layer 2 are formed. Further, lower electrodes (back surface electrodes) 5a and 5b are formed at the lower end of the substrate. And in order to electrically connect upper electrode 4a, 4b and lower electrode 5a, 5b to each edge part side surface of the board | substrate 1, edge part electrode 6a, 6b is arrange | positioned between these electrodes.

  Further, an external electrode 8a is formed by, for example, plating so as to cover the lower electrode 5a and the end electrode 6a. Similarly, an external electrode 8b is formed by plating or the like so as to cover the lower electrode 5b and the end electrode 6b.

  As an insulating substrate used in such a resistor, for example, an alumina substrate, a forsterite substrate, a mullite substrate, an aluminum nitride substrate, a glass ceramic substrate, or the like can be used. In addition, in the resistance layer 2, as the conductive metal component, a metal mixed powder obtained by mixing each metal powder of copper, manganese, iron (Cu—Mn—Fe) blended in the above-described ratio, or copper, Use manganese and iron alloy powders. In addition, when mixing and using each powder of copper, manganese, and iron, it alloyed at the time of baking.

  Next, a manufacturing process of the resistor according to the present embodiment having the above-described configuration will be described. FIG. 4 is a process diagram for explaining the manufacturing process of the resistor according to the present embodiment. First, in step S <b> 11 of FIG. 4, the above-described process for manufacturing the substrate 1 is executed. Here, an alumina substrate of 96 wt% alumina is used as the substrate. As the substrate shape, for example, a rectangular substrate having a manufacturing unit size is manufactured, but the size of the substrate to be manufactured is arbitrary, and even a substrate having a size for each resistor, or A number of resistor-sized substrates may be manufactured simultaneously.

In subsequent step S12, the bottom electrode (back electrode) 5a, 5b is formed by printing a thick film of the back electrode by screen printing on the lower surface of the substrate 1 (solder surface when the resistor is mounted) and baking it. Specifically, a copper paste (Cu paste) is printed on the back surface of the alumina substrate, and then dried and baked in a nitrogen (N ₂ ) atmosphere at, for example, 960 ° C. for 10 minutes to form a back electrode. .

  Next, in step S13, the upper electrodes (surface electrodes) 4a and 4b are formed on the upper surface (side on which the resistor is formed) of the substrate 1 by printing a thick film of the surface electrode by screen printing and baking. Specifically, a copper paste is printed on the surface of the alumina substrate, then dried, and baked in a nitrogen atmosphere at, for example, 960 ° C. for 10 minutes to form a surface electrode. The upper electrodes (surface electrodes) 4a and 4b and the lower electrodes (back electrodes) 5a and 5b may be fired simultaneously.

In this embodiment, for example, by using a copper paste as an electrode material for thick film printing on both the back surface and the front surface, the problem of reliability degradation due to silver electronic migration can be avoided as in conventional resistors. Yes. Further, the firing in a nitrogen (N ₂ ) atmosphere that is an inert atmosphere is to prevent oxidation of copper as an electrode. The firing temperature is not limited to 960 ° C., and may be fired at 980 ° C., for example.

In step S14, for example, the resistor paste described above is applied between the upper electrodes (surface electrodes) 4a and 4b so that a part of the resistor paste overlaps the upper electrodes (surface electrodes) 4a and 4b. Form. Then, this thick resistor paste film is baked, for example, at 960 ° C. in a nitrogen (N ₂ ) atmosphere. The firing temperature may be 980 ° C.

  In this embodiment, by adding copper oxide and / or glass (for example, ZnBSiOx glass) to the resistor paste, good adhesion between the substrate and the fired resistor is obtained, and the glass is used. The strength of the resistor film can be obtained. The vehicle functions so that printing suitability with an organic binder can be obtained during printing.

  In step S15, a pre-glass coat thick film is formed on the resistor layer 2 thus formed by printing or the like, dried, and then fired (formation of glass coating). Here, for example, a ZnBSiOx glass paste is printed on the resistor layer, and then dried, and then baked in a nitrogen atmosphere at, for example, 670 ° C. for 10 minutes to form a pre-glass coat. The firing temperature may be 690 ° C. Further, the glass paste is not limited to the ZnBSiOx glass paste, and the above-described barium borosilicate glass, calcium borosilicate glass, barium calcium borosilicate glass, zinc borosilicate glass, and zinc borate glass are used. be able to.

  Next, in step S16, resistor trimming (resistance value adjustment) is performed as necessary. In this trimming, for example, the resistance value is adjusted by cutting the resistor pattern with a laser beam or sandblast.

  In step S17, for example, an epoxy resin is formed by screen printing or the like so as to cover the pre-glass coat and the upper electrodes 4a and 4b, and is cured to form the protective film 3 that also functions as an insulating film. An overcoat is formed. The protective film 3 is not limited to an epoxy resin, and a modified epoxy resin, a phenol resin, a polyimide resin, a silicone resin, or the like can be used.

  Thereafter, a colored epoxy phenol resin or the like is printed on the overcoat (protective film) as necessary, and is cured to form a display portion for displaying a resistance value or the like.

  In step S18, A break (primary break) is performed to divide the alumina substrate into strips. In subsequent step S19, a NiCr alloy film is formed on the end face of the alumina substrate on the strip by a sputtering method, and end electrodes 6a and 6b are formed. The formation of the NiCr alloy film is not limited to the sputtering method, and may be formed by vapor deposition or the like.

  Next, in step S20, B break (secondary break) is performed, and the strip-shaped alumina substrate on which the end electrodes 6a and 6b are formed is further divided into individual pieces (chips). The size of the obtained piece (chip) is, for example, 3.2 mm × 1.6 mm. In step S21, external electrodes 8a and 8b are formed on the portions of the upper electrodes 4a and 4b that are not covered with the protective film 3, and on the lower electrodes 5a and 5b and the end electrodes 6a and 6b.

  For example, the external electrodes 8a and 8b are sequentially subjected to electrolytic nickel (Ni) plating-electrolytic copper (Cu) plating-electrolytic nickel (Ni) plating-electrolytic tin (Sn) plating, and Ni film-Cu film-Ni film- It is assumed that the Sn film is laminated.

  The resistor having a chip size of 3.2 mm × 1.6 mm manufactured as described above has, for example, a substrate thickness of 470 μm, a top electrode thickness of 20 μm, a bottom electrode thickness of 20 μm, a resistor layer thickness of 30 to 40 μm, The precoat thickness is 10 μm, the protective film thickness is 30 μm, the end electrode thickness is 0.05 μm, and the external electrode thickness is, in order, Ni film thickness of 3 to 7 μm, Cu film thickness of 20 to 30 μm, Ni film thickness of 3 The thickness is 12 μm and the Sn film thickness is 3 to 12 μm.

  In the case of manufacturing a resistor using the resistor paste according to this embodiment, the resistor paste firing method and the fired resistor are used in a neutral atmosphere or an inert atmosphere (for example, In a nitrogen atmosphere) at 600 ° C. to 1000 ° C. The firing time of the resistor paste can be set arbitrarily. Thereby, a copper-manganese-iron based resistor, more preferably, a copper-manganese-iron alloy resistor can be obtained.

  As described above, according to the present embodiment, the material of the resistor paste is a mixture of conductive metal powder of copper-manganese-iron (Cu-Mn-Fe), glass powder, and By mixing copper oxide powder and firing it to produce a resistor, the resistivity can be lowered compared to a resistor produced from a resistor paste made of copper-nickel, and At the same time, the TCR of the resistor and the thermoelectromotive force against copper can be lowered.

  Further, since a resistor chip having such characteristics can be used to manufacture a chip resistor, such a resistor has a low resistivity, such as a current detection resistor (shunt resistor) of a power supply circuit or a motor circuit. And chip resistors that are ideal for applications requiring low TCR resistors.

It is a flowchart which shows the manufacturing process of the resistor paste which concerns on the embodiment of this invention. It is a figure which shows the composition of the resistor which concerns on the embodiment. It is a figure which shows the cross-sectional structure of the chip resistor which concerns on the example of embodiment. It is a flowchart for demonstrating the manufacturing process of the resistor which concerns on the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Resistance layer 3 Protective film 4a, 4b Upper electrode (surface electrode)
5a, 5b Lower electrode (back electrode)
6a, 6b End electrode 7 Pre-glass 8a, 8b External electrode (plating)

Claims (3)

An electrically insulating substrate;
A resistance layer formed on the substrate;
A pair of electrodes disposed at both ends of the resistance layer and in electrical contact with the resistance layer;
The pair of electrodes is made of copper, and the resistance layer includes 84 to 88 wt% copper, 11 to 13 wt% manganese, and 1 to 3 wt% iron as metal components, and further 100 wt% of the metal components. A current detection resistor comprising glass powder and / or copper oxide powder in an amount not exceeding 10 parts by weight with respect to the part. The resistance layer includes copper oxide, which is CuO or Cu ₂ The current detection resistor according to claim 1, wherein the current detection resistor is any one of O. Preparing an electrically insulating substrate having a size corresponding to a plurality of resistors for current detection;
Forming an electrode by printing a copper paste on the electrically insulating substrate;
84 to 88 wt% copper, 11 to 13 wt% manganese, and 1 to 3 wt% iron as metal components, and glass powder and / or copper oxide powder with respect to 100 parts by weight of the metal components. A step of producing a resistor paste comprising not more than 10 parts by weight and further comprising 10 to 15 parts by weight of a vehicle;
Forming a resistor by printing so that a part of the resistor paste overlaps the electrode; and
Forming a protective film for protecting the resistor;
And a step of dividing the substrate after forming the protective film into individual pieces.

Images