JP2007123301A - Microminiature chip resistor and resistor paste for microminiature chip resistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide resistor paste for microminiature chip resistor having a low resistance and a low TCR. <P>SOLUTION: In paste at least composed of: copper based conductive metal powder containing copper powder; glass frit; and an organic vehicle, silver powder is added to the copper based conductive metal powder. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chip resistor used in a current detection circuit or the like provided in an electronic circuit or a power supply circuit, and more particularly, an ultra-small chip resistor having a low resistance value and a low resistance temperature coefficient, and a resistance for an ultra-small chip resistor. It relates to body paste.

  In recent years, as typified by mobile phones and notebook computers, the demand for small electronic devices has been increasing, and the downsizing and high performance of these electronic devices have led to the downsizing of chip-type electronic components used in this, It depends heavily on high performance.

  An example of a conventional chip resistor manufacturing method will be described with reference to FIG. In FIG. 3A, the paste for the surface electrode 22 is printed so as to face both end portions of the upper surface of the alumina substrate 21 (having cutting grooves formed vertically and horizontally). The back electrode 23 paste is printed so as to face each other. These surface electrode 22 paste and back electrode 23 paste are dried and fired simultaneously. Next, the resistor 24 paste is printed on the central portion of the upper surface of the alumina substrate 21 so as to connect the surface electrodes 22 and 22 on both ends of the upper surface of the alumina substrate 21, dried, and fired. Then, in order to adjust the resistance value as necessary, a part of the resistor 24 is removed by means such as laser trimming. Furthermore, a paste for the glass layer 25 is printed so as to cover the resistor 24, dried and fired. Next, the paste for the protective film 26 is printed on the glass layer 25, dried and fired. Then, the alumina substrate 21 is cut into a strip shape along a cutting groove perpendicular to the paper surface. Further, a paste for the end face electrode 27 is applied to a pair of opposing end faces of each strip-like alumina substrate 21 so as to connect the front electrode 22 and the back electrode 23, dried and fired. Next, each alumina substrate 21 is cut into an actual chip resistor size along the cutting groove in the paper surface direction. Finally, a copper plating film 28 is formed by electroplating so as to cover the end face electrode 27, a nickel film 29 is formed by electroplating so as to cover the copper plating film 28, and a tin plating film 30 is covered so as to cover the nickel film 29. Is formed by electroplating.

  In the chip resistor manufactured by the method as described above, a thick film resistor material mainly composed of ruthenium oxide is often used as the conductive particles serving as a resistor. A resistor material made of ruthenium oxide has a temperature coefficient of resistance (hereinafter also referred to as TCR) indicating a change in temperature of the resistance value as low as ± 50 ppm / ° C. by adding a TCR adjusting material such as a metal oxide. It is possible to do. However, since the specific resistance of ruthenium oxide is high, it is difficult to provide a chip resistor having a low resistance temperature coefficient and a low resistance value. Therefore, a chip resistor or resistor paste as described below has been proposed.

  For example, Patent Document 1 discloses a resistor including a resistor containing 10 parts by weight or less of glass powder and copper oxide powder when the metal components of copper, manganese, and germanium are 100 parts by weight. Has been.

  Patent Document 2 discloses that 3 to 20 parts by weight of glass powder and 1 to 10 parts by weight of copper oxide powder with respect to 100 parts by weight of conductive powder made of mixed powder of copper powder and nickel powder or Cu-Ni alloy powder. Is disclosed in which a conductive paste is dispersed in an organic vehicle so that the proportion of the conductive component is 75 to 90% by weight.

  In Patent Document 3, 1 to 10 parts by weight of copper oxide and 1 to 12 parts by weight of aluminum oxide are used for 100 parts by weight of an insulating base and copper and nickel formed on the insulating base. A resistor comprising a resistor and a resistor having 1 to 10 parts by weight of a glass component is disclosed.

  Patent Document 4 discloses a resistor paste including a conductive powder made of copper and nickel, a glass powder not containing cadmium having a softening point of 400 to 500 ° C., a metal oxide, and a vehicle.

  Patent Document 5 includes a first mixed powder made of copper powder, manganese powder and tin powder, an alloy powder of copper, manganese and tin, and a first mixed powder and alloy powder. A resistor paste made of a conductive metal powder made of at least one of the second mixed powders, a glass powder, a copper oxide powder, and an organic vehicle is disclosed.

  Patent Document 6 discloses a resistor including an insulating base, a metal component formed of copper, nickel, and manganese formed on the insulating base, a copper oxide, and a resistor having a glass component. Yes.

Patent Document 7 discloses a resistor having an insulating base, a metal component made of copper and nickel formed on the insulating base, a metal oxide component made of copper oxide and iron oxide, and a glass component. A resistor is disclosed.
JP 2004-104047 A Japanese Patent Laid-Open No. 11-288801 JP 2003-347102 A JP 11-233302 A JP 2004-119692 A JP 2004-119561 A JP 2003-324002 A

  By the way, the performance of the resistor is evaluated by integrating all of the electrode and the resistor portion and the resistor that overlap with the electrode. However, when the resistor is miniaturized, the resistance value and the TCR tend to increase. This is because, as shown in FIG. 3B, the small chip resistor has a small dimension between the electrode 31 and the resistor 32 itself, but the distance D between the electrodes 31 and 31 is extremely short compared to the dimension. . For this reason, the ratio of the portion where the electrode and the resistor overlap (the hatched portion) occupies the entire area of the resistor. As a result, the resistance value of the chip resistor tends to be high, and the TCR tends to be high because the resistor is easily affected by the electrode characteristics due to the mutual diffusion of the elements constituting the electrode and the resistor in the overlapping portion. .

  In this regard, Patent Document 1 describes that a resistor having a TCR of 300 ppm / ° C. or less is obtained and can be applied to a chip resistor having a size of 3.2 mm × 1.6 mm. However, it is not described that the present invention can be applied to a micro chip resistor (size of 1.0 mm × 0.5 mm) which is an object of the present invention.

  Moreover, the sheet resistance value of the resistor paste described in Patent Document 2 is 50 mΩ / □ or less and the TCR is 200 ppm / ° C. or less, but it is not described that the resistor paste can be applied to an ultra-small chip resistor.

  Patent Document 3 describes that a chip resistor having a size of 3.2 mm × 1.6 mm has a sheet resistance value of 200 mΩ / □ or less and a TCR within ± 100 ppm / ° C. It is not described that it can be applied to a micro chip resistor.

  Moreover, the sheet resistance value of the resistor paste described in Patent Document 4 is 50 mΩ / □ or less and the TCR is within ± 100 ppm / ° C., but it is not described that the resistor paste can be applied to an ultra-small chip resistor.

  Patent Document 5 describes that a chip resistor having a size of 3.2 mm × 1.6 mm has a resistance value of 50 mΩ or less and a TCR of 300 ppm / ° C. or less. It is not described that it can be applied to resistors.

  Further, Patent Document 6 describes that a chip resistor having a size of 3.2 mm × 1.6 mm has a resistance value of 50 mΩ or less and a TCR of 500 ppm / ° C. or less. It is not described that it can be applied to resistors.

  The sheet resistance value of the resistor paste described in Patent Document 7 is 100 mΩ / □ or less, and the TCR is 200 ppm / ° C. or less, which is applicable to a chip resistor having a size of 3.2 mm × 1.6 mm. Although it is described, it is not described that it is applicable to a micro chip resistor.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a resistor paste for an ultra-small chip resistor having a low resistance value and a low TCR, and a resistor comprising such a paste. An object of the present invention is to provide an ultra-small chip resistor having a body.

  In order to achieve the above object, a resistor paste for an ultra-small chip resistor according to the present invention is an ultra-small chip resistor resistor paste comprising at least copper-containing copper-based conductive metal powder, glass frit, and an organic vehicle. It is characterized by adding silver powder to the system conductive metal powder.

  It is preferable to add 1 to 10 parts by weight of silver powder to 100 parts by weight of copper-based conductive metal powder.

  When the copper-based conductive metal powder is a mixed powder containing a copper powder essentially containing the copper powder, the copper powder in 100 parts by weight of the copper-based conductive metal powder is preferably 40 to 80 parts by weight.

  When the copper-based conductive metal powder is a mixed powder containing a copper-containing alloy powder essential for copper, the copper-containing alloy powder in 100 parts by weight of the copper-based conductive metal powder may be 50 to 60 parts by weight. preferable.

  The copper-based conductive metal powder is essentially a copper powder, and a mixed powder containing a copper powder obtained by mixing this copper powder with at least one of nickel powder, manganese powder, tin powder or zinc powder. Copper-containing alloy powder consisting of an alloy of copper and at least one metal selected from nickel, manganese, tin or zinc, or copper powder, nickel powder, manganese powder, tin powder or A mixed powder containing a copper-containing alloy powder obtained by mixing at least one kind of powder in zinc powder and the copper-containing alloy powder is preferable.

  The present invention lowers the resistance value by adding silver powder to the copper-based conductive metal powder, and the silver powder has the property of shifting the TCR to the positive side, so the copper-based conductive metal powder in the negative TCR region Can be controlled within a limited range near the origin.

  Therefore, it is possible to provide an ultra-small chip resistor having a low resistance and a low TCR by using a copper-based conductive metal powder added with silver powder as a resistor paste for an ultra-small chip resistor. .

  The best mode for carrying out the present invention will be described below.

  In this specification, copper conductive powder is essential as copper-based conductive metal powder, and this copper powder is mixed with at least one powder of nickel powder, manganese powder, tin powder or zinc powder. Mixed powder containing powder, copper is essential, copper-containing alloy powder consisting of an alloy of this copper and at least one metal of nickel, manganese, tin or zinc, or copper powder, nickel powder, A mixed powder containing a copper-containing alloy powder obtained by mixing at least one kind of powder among manganese powder, tin powder or zinc powder and the copper-containing alloy powder is preferable. Copper is an essential component for obtaining a low-resistance resistor having a low resistance value, but copper alone has an extremely large TCR and is not suitable for use as a resistor. Nickel, manganese, tin, and zinc have higher resistance values than copper.

  However, firing a mixture of copper powder with nickel powder, manganese powder, tin powder or zinc powder will reduce the excess surface energy of the powder, that is, in the direction of reducing the surface area. Movement occurs and bonding between particles occurs. Although the change of the microstructure in the sintering process is complicated, it can be considered in the following three stages. (1) In the initial stage, adhesion between particles occurs, and the area of this portion gradually increases. This change is called cervical growth. At this stage, the relative density (ratio of the sintered body density to the theoretical density) is about 0.5 to 0.6, and the shrinkage is about 4 to 5%. (2) In the middle stage, the channel-like voids are gradually narrowed, the relative density is 0.6 to 0.95, the shrinkage rate is close to 5 to 20%, and the particle growth is remarkable. (3) At the final stage, the relative density becomes 0.95 or more, and only voids remain in the corners and grains of the polyhedral particles. Densification further proceeds by the disappearance of the voids. Sintering mechanisms can be broadly divided into evaporation-condensation mechanisms, diffusion mechanisms, dissolution-precipitation mechanisms, and flow mechanisms, but the actual sintering phenomenon is often complicated by a mixture of several mechanisms. It is a phenomenon.

  Furthermore, unlike the sintering of single-phase powders, in the case of sintering different types of mixed powders, the driving force proportional to the concentration gradient of the components is greater than the driving force due to surface stress. It plays a major role in interparticle bonding and densification. However, since the diffusion coefficient values between different components are generally different, the diffusion flow becomes non-uniform, and voids and deep grooves are formed near the coupling neck due to the so-called Kirkendall effect, and irregularities are formed on the particle surface. It exhibits complex morphological changes. In the sintered body of different metal powders, the presence of pores (sintered body density) is the main cause and exhibits different electromagnetic properties from the molten metal of the same composition. In addition to the density of the sintered body, the presence of the sintered structure and impurities also affects the electromagnetic properties of the sintered body of the dissimilar metal powder. Therefore, the electromagnetic properties of the sintered body vary depending on the mixing ratio of the different metal powders and the powder particle size.

As described above, the sintered body of the dissimilar metal powder exhibits different electromagnetic properties from the molten metal having the same composition. As a result, a sintered body obtained by firing a copper conductive metal powder in which nickel powder, manganese powder, tin powder or zinc powder is mixed with copper powder, a glass frit, and a paste made of an organic vehicle is obtained. Although the resistance value increases as compared with a sintered body obtained by firing an organic vehicle paste, the temperature coefficient of resistance generally decreases due to the presence of pores resulting from firing. In the present invention, the temperature coefficient of resistance is a numerical value defined below. The sample is allowed to stand at temperatures T ₀ ° C and T ₁ ° C for 30 minutes or more, and resistance values R ₀ and R ₁ at the respective temperatures are measured, and the resistance temperature coefficient is calculated from the following equation (1).

  According to the present invention, the resistance value of the resistor can be reduced by adding an appropriate amount of silver powder to the copper-based conductive metal powder. The metal bond radius (1.44 mm) of silver is larger than the metal bond radius (1.48 mm) of copper, and nickel, manganese, zinc and the like have a metal bond radius smaller or slightly larger than copper. Therefore, the vacancy status of the sintered body of these copper-based conductive metal powders is different from the vacancy status of the sintered body of the mixed powder obtained by adding silver powder to the copper-based conductive metal powder. Therefore, the TCR tends to shift to the positive side. As a result, it is possible to control the TCR of the sintered body of copper-based conductive metal powder in the minus TCR region within a limited range near the origin.

  By adding 1 part by weight or more of silver powder to 100 parts by weight of copper-based conductive metal powder, the resistance value of the resistor can be reduced. Since silver powder has the property of shifting TCR to plus, adding more than 10 parts by weight of silver powder is not preferable because the increase in TCR becomes too large.

  The ratio of the copper powder in 100 parts by weight of the copper-based conductive metal powder is preferably as follows in relation to the particle size of the copper powder.

  When the copper-based conductive metal powder is a mixed powder containing a copper powder essentially containing the copper powder (average particle diameter of the copper powder = 1.5 to 2.5 μm), in 100 parts by weight of the copper-based conductive metal powder The copper powder is preferably 80 parts by weight or less. This is because if the copper powder exceeds 80 parts by weight, the initial TCR becomes too high. On the other hand, the copper powder in 100 parts by weight of the copper-based conductive metal powder is preferably 40 parts by weight or more. This is because if the copper powder is less than 40 parts by weight, the initial resistance value becomes too high.

  When the copper-based conductive metal powder is a mixed powder containing a copper-containing alloy powder essential for copper (average particle size of the copper-containing alloy powder = 4.5 to 5.5 μm), the copper-based conductive metal powder 100 The copper-containing alloy powder in parts by weight is preferably 60 parts by weight or less. This is because if the copper-containing alloy powder exceeds 60 parts by weight, the initial TCR becomes too high. On the other hand, the copper-containing alloy powder in 100 parts by weight of the copper-based conductive metal powder is preferably 50 parts by weight or more. This is because the initial resistance value becomes too high when the copper-containing alloy powder is less than 50 parts by weight.

  The particle size of the conductive metal powder excluding copper is preferably 0.1 to 10 μm. If it is less than 0.1 μm, there is a disadvantage that blistering is likely to occur due to oversintering, and if it exceeds 10 μm, there is a disadvantage that sintering is difficult.

  The glass frit is not limited, and borosilicate barium glass, calcium borosilicate glass, barium calcium borosilicate glass, zinc borosilicate glass, zinc borate glass, and the like can be used.

  The particle size of the glass frit is preferably within the range that can be used for screen printing, and for example, the particle size is preferably 0.1 to 10 μm.

  Examples of the resin used in the organic vehicle include ethyl cellulose, ethyl acrylate, butyl acrylate, ethyl methacrylate, butyl methacrylate and the like. Examples of the solvent used in the organic vehicle include terpineol, xylene, toluene and the like.

  The glass frit is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the copper-based conductive metal powder. This is because if the glass frit is less than 1 part by weight, the adhesive strength is weak, and if it exceeds 10 parts by weight, the resistance value increases and the glass tends to exude.

  The organic vehicle is preferably 10 to 30 parts by weight with respect to 100 parts by weight of the total of the copper-based conductive metal powder and the glass frit. This is because when the organic vehicle is less than 10 parts by weight, the viscosity of the resistor paste is high and the printability is poor, and when it exceeds 30 parts by weight, the viscosity of the resistor paste becomes too low and sagging occurs during printing.

  In addition, additives such as alumina powder and a dispersant can be used for adjusting the film properties.

Examples of the present invention will be described below. However, the present invention is not limited to the following examples, and can be appropriately changed and modified without departing from the technical scope of the present invention.
(1) Ultra-small chip resistor FIG. 1A is a partially broken perspective view of an ultra-small chip resistor (1.0 mm × 0.5 mm) to which the resistor paste of the present invention can be applied, FIG. ) Is a cross-sectional view taken along the line B-B in FIG. 1A, and FIG.

  In FIGS. 1A, 1B, and 1C, reference numeral 1 denotes an alumina substrate (having cutting grooves formed in the vertical and horizontal directions) so as to be opposed to both ends with the central portion of the upper surface of the alumina substrate 1 being left. The first front electrodes 2 and 2 are formed, the first front electrodes 2 and 2 at both ends are connected by a resistor 3 that covers the central portion of the upper surface of the alumina substrate 1, and laminated on the first front electrodes 2 at both ends. A part of the resistor 3 is accommodated in the second surface electrode 4, a part of the second surface electrode 4 is protected by the protective film 5 laminated on the resistor 3, and opposed to both ends of the lower surface of the alumina substrate 1. The back electrodes 6 and 6 are formed, and the chromium thin film 7 is formed so as to connect the second front electrode 4, the first front electrode 2 and the back electrode 6 to a pair of opposite end faces of the alumina substrate 1, A nickel thin film 8 is formed so as to cover the chromium thin film 7, and further, a portion of the second front electrode 4 that is not protected by the protective film 5, To cover the Kell film 8 and back electrode 6, the copper plating film 9, a nickel plating film 10 are sequentially formed tin plating film 11.

The microchip resistor configured as described above can be manufactured as follows. First, the paste composition for the first front electrode 2 and the paste composition for the back electrode 6 are printed, dried and then simultaneously fired in an inert gas atmosphere. Next, the paste composition for the resistor 3 is printed, dried, and fired in an inert gas atmosphere. Next, the paste composition for the second front electrode 4 is printed, dried, and fired in an inert gas atmosphere. In order to adjust to a desired resistance value as required, a part of the resistor 3 is removed by means such as laser trimming. Further, a resin paste for the protective film 5 is printed and baked. Next, the alumina substrate 1 is cut into strips along a cutting groove perpendicular to the paper surface. A chromium thin film 7 is formed by sputtering on a pair of opposite end faces of each strip-shaped alumina substrate 1, and a nickel thin film 8 covering the chromium thin film 7 is formed by sputtering. Next, each alumina substrate 1 is cut into the size of an actual chip resistor along the cutting groove in the paper surface direction. Finally, a copper plating film 9, a nickel plating film 10, and a tin plating film 11 are sequentially formed by electroplating so as to cover the portion of the second front electrode 4 that is not protected by the protective film 5, the nickel thin film 8 and the back electrode 6. To do.
(2) Resistor Paste When the chip resistor of FIG. 1 is compared with the chip resistor of FIG. 3A, the chip resistor of FIG. 1 is different in that the surface electrode is composed of two layers. However, although the resistance can be reduced by making the surface electrode into two layers, the ultra-small chip resistor having a size of 1.0 mm × 0.5 mm constitutes a conductive paste of the electrode and the resistor. Even when the composition of the alloy powder and the ratio between the alloy powder and the glass frit were adjusted, a low resistance value (100 mΩ or less) and a low TCR (300 ppm / ° C. or less) could not be realized. The reason for this is that in the ultra-small chip resistor, the ratio of the area of the overlapping portion (shaded portion) of the resistor and the electrode to the area of the entire resistor shown in FIG. It is considered that the resistance value and the low TCR could not be realized.

  Therefore, the present inventor has developed a resistor paste for ultra-small chip resistors. Specifically, as shown in Table 1, a mixed metal containing copper powder comprising copper powder having an average particle size of 2.2 μm, nickel powder having an average particle size of 0.7 μm, and silver powder having an average particle size of 1.8 μm. Contains a copper-containing alloy powder comprising a powder (sample No = 1 to 12) or a copper-containing alloy powder having an average particle diameter of 5.0 μm, a nickel powder having an average particle diameter of 0.7 μm, and a silver powder having an average particle diameter of 1.8 μm. For mixed metal powder (sample No = 13-25), copper powder or copper-containing alloy powder and nickel powder blended at a weight ratio as shown in the same table, silver powder is 1-10 wt. Further, 6 parts by weight of glass frit (borosilicate glass) was blended, 19 parts by weight of organic vehicle (terpineol solution of ethyl cellulose) was blended, and kneaded by a three roll mill to prepare a resistor paste. The copper-containing alloy powder is a powder made of an alloy having a weight ratio of Cu: Mn: Sn = 92: 6: 2.

  This paste is screen-printed on an alumina substrate with a pattern as shown in FIG. 2 (wiring width W = 1 mm, L = full length of wiring, L / W = 220), dried, and dried at 900 ° C. in a nitrogen atmosphere at 900 ° C. The test resistor pattern was formed by baking for a minute. Then, the sheet resistance (mΩ / □ / 10 μm) and TCR of this resistor pattern were measured. The results are shown in Table 1.

  The resistance value was measured by a four-terminal method using a tester after the sample was allowed to stand for 30 minutes in a constant temperature and constant humidity atmosphere at a temperature of 25 ° C. and a relative humidity of 65%.

In addition, TCR is a method in which a sample is left in an atmosphere of 25 ° C. (T ₀ ) and 125 ° C. (T ₁ ) for 30 minutes, and then each resistance value (R ₀ , R ₁ ) is measured by a four-terminal method using a tester. Was repeated 5 times, and the average value of 5 times of the numerical value calculated from the formula (1) was adopted.
(3) Ultra-small chip resistor Further, in the ultra-small chip resistor having the structure shown in FIG. 1, the resistor 3 is made of the paste having the above composition, and the first front electrode 2, the second front electrode 4, and the back electrode 6 are formed. In the conductive paste composition, the conductive metal powder is copper powder, the glass frit is borosilicate glass, the organic vehicle is terpineol solution of ethyl cellulose, the conductive metal powder is 100 parts by weight, the glass frit is 6 parts by weight, An ultra-small chip resistor having a composition comprising 19 parts by weight of an organic vehicle was produced.

  And the resistance value and TCR of this ultra-small chip resistor were measured by the above method. The results are shown in Table 1.

From Table 1, the following points are clear.
(1) The resistance value increases as the blending ratio of the copper powder or the copper-containing alloy powder decreases, whereas the TCR tends to decrease.
(2) Although the TCR of the copper powder alone is extremely large, the TCR can be rapidly reduced by adding nickel powder. However, when nickel powder is blended, there is a disadvantage that the resistance increases.

  Therefore, when an appropriate amount of silver powder is added as in sample Nos. 4 to 7 and sample Nos. 18 to 22, the resistance value can be lowered and the TCR can be kept within a certain range.

  In the case of using a mixed powder (copper powder average particle size = 2.2 μm) containing copper powder that essentially requires copper powder as the copper-based conductive metal powder, the copper powder and nickel powder are mixed with 80:20 to 40 : By using a conductive metal powder in which 1 to 10 parts by weight of silver powder is added to 100 parts by weight of a compound with a weight ratio of 60, the resistance value is about 100 mΩ or less and the TCR is about 300 ppm / ° C. or less. It is possible to obtain a very small chip resistor having a low resistance and a low TCR.

  However, in the case of using a mixed powder containing copper powder that essentially requires copper powder as the copper-based conductive metal powder (average particle diameter of copper powder = 2.2 μm), the mixed powder of copper powder and nickel powder When the blending ratio of the copper powder is 90% or more, the initial TCR is too high, so that it is difficult to obtain a small chip resistor with low resistance and low TCR even if silver powder is added. Also, if the blending ratio of the copper powder in the mixed powder of copper powder and nickel powder is 30% or less, the initial TCR is too high, so even if silver powder is added, low resistance and low TCR ultra-small chip resistance It is difficult to obtain a vessel.

  In the case of using a mixed powder containing a copper-containing alloy powder that essentially requires copper as the copper-based conductive metal powder (average particle diameter of the copper-containing alloy powder = 5 μm), the copper-containing alloy powder and the nickel powder are: By using a conductive metal powder in which 1 to 10 parts by weight of silver powder is added to 100 parts by weight of 40 to 50:50, the resistance value is about 100 mΩ or less and the TCR is about 300 ppm / It is possible to obtain an ultra-small chip resistor having a low resistance and a low TCR of ℃ or less.

  However, when using a mixed powder containing a copper-containing alloy powder in which copper is essential as the copper-based conductive metal powder (average particle diameter of the copper-containing alloy powder = 5 μm), the mixture of the copper-containing alloy powder and the nickel powder is used. If the compounding ratio of the copper-containing alloy powder in the powder is 70% or more, the initial TCR is too high, so even if silver powder is added, it is difficult to obtain an ultra-small chip resistor with low resistance and low TCR. is there. Moreover, when the blending ratio of the copper-containing alloy powder in the mixed powder of the copper-containing alloy powder and the nickel powder is 40%, the initial resistance value is increased, and when the blending ratio of the copper-containing alloy powder is 30% or less, Since the initial TCR is too high, it is difficult to obtain an ultra-small chip resistor having a low resistance and a low TCR even if silver powder is added.

FIG. 1A is a partially broken perspective view of an ultra-small chip resistor (1.0 mm × 0.5 mm) to which the resistor paste of the present invention can be applied, and FIG. 1B is a diagram of FIG. BB arrow sectional drawing, FIG.1 (c) is an enlarged view of the end surface part of FIG.1 (b). It is a top view which shows an example of the printing pattern of a resistor paste. FIG. 3A is a sectional view of a conventional small chip resistor, and FIG. 3B is a plan view for explaining the overlapping state of the resistor and the electrode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Alumina substrate 2 1st surface electrode 3 Resistor 4 2nd surface electrode 5 Protective film 6 Back electrode 7 Chromium thin film 8 Nickel thin film 9 Copper plating film 10 Nickel plating film 11 Tin plating film 21 Alumina substrate 22 Front electrode 23 Back electrode 24 Resistance Body 25 Glass layer 26 Protective film 27 End electrode 28 Copper plating film 29 Nickel plating film 30 Tin plating film 31 Electrode 32 Resistor

Claims (6)

  An ultra-small chip resistor characterized by adding silver powder to a copper-based conductive metal powder in a resistor paste for an ultra-small chip resistor comprising a copper-based conductive metal powder containing at least copper, glass frit, and an organic vehicle. A resistor paste.   The resistor paste for an ultra-small chip resistor according to claim 1, wherein 1 to 10 parts by weight of silver powder is added to 100 parts by weight of copper-based conductive metal powder.   The copper-based conductive metal powder is essentially a copper powder, and a mixed powder containing a copper powder obtained by mixing this copper powder with at least one of nickel powder, manganese powder, tin powder or zinc powder. Copper-containing alloy powder consisting of an alloy of copper and at least one metal selected from nickel, manganese, tin or zinc, or copper powder, nickel powder, manganese powder, tin powder or 3. The resistance for an ultra-small chip resistor according to claim 1, wherein the resistor is a mixed powder containing a copper-containing alloy powder obtained by mixing at least one kind of powder in zinc powder and the copper-containing alloy powder. Body paste.   4. The superconducting powder according to claim 3, wherein when the copper-based conductive metal powder is a mixed powder containing copper powder, the copper powder in 100 parts by weight of the copper-based conductive metal powder is 40 to 80 parts by weight. Resistor paste for small chip resistors.   The copper-containing alloy powder in 100 parts by weight of the copper-based conductive metal powder is 50-60 parts by weight when the copper-based conductive metal powder is a mixed powder containing a copper-containing alloy powder. 3. The resistor paste for an ultra-small chip resistor according to 3.   6. An ultra-small chip resistor using a paste obtained by firing the paste according to claim 1 as a resistor.

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