JPH07111203A - Manufacture of chip resistor and its structure body - Google Patents

Abstract

PURPOSE:To improve the dimensional accuracy of a chip resistor by forming an insulating substrate by sintering a laminated body of a first and second glass ceramic green sheets and forming electrodes, resistors, and protective films on the surface of the substrate having higher thermal conductivity and dividing grooves on the other surface of the substrate. having lower thermal conductivity. CONSTITUTION:A laminated body 3 of green sheets is formed by piling up a first and second glass ceramic green sheets 1 and 2 upon another and thermocompression bonding the sheets 1 and 2 to each other. Then an insulating substrate 4 having anisotropic heat conductivity is formed by sintering the laminated body 3 in a belt furnace. After forming electrodes 5 and printing and baking resistor patterns and protective film patterns on the surface of the substrate 4 having higher heat conductivity, resistors 6 and protective films 7 are formed. In addition, dividing grooves are formed on the other surface of the substrate 4 with a machining blade so as to divide the substrate 4 into individual chip resistor pieces. Therefore, a chip resistor having a desired size and high dimensional accuracy can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a chip resistor and its structure, which can be suitably applied mainly to electronic equipment which requires high-density mounting technology.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a chip resistor,
A 96% by weight alumina substrate, which was previously sintered with a slit for division at the green sheet stage, was used as an insulating substrate, and after forming electrodes, resistors and a protective film on this insulating substrate,
A method of dividing by a dividing slit and forming end face electrodes on both side faces of the divided chip has been adopted.

Further, Japanese Utility Model Publication No. 64-6006 discloses that
A structure of a chip resistor in which a good thermal conductive film is formed in the central portion of the lower surface of the insulating substrate of the chip resistor has been proposed.

An example of the structure of the chip resistor provided with this heat dissipation measure will be described below with reference to FIG.

In FIG. 5, 21 is an insulating substrate, 22 is an electrode formed on the upper surface thereof, 23 is a resistor, 24 is a protective film, 25 is a good heat conductive film formed on the lower surface of the insulating substrate 21, and 26 is. It is an end surface electrode formed on both side surfaces.

When manufacturing such a chip resistor,
As the insulating substrate 21, a sintered 96 wt% alumina substrate having slits for division is used.
An electrode 22, a resistor 23, and a protective film 24, which correspond to a plurality of chip resistors, are formed on the upper surface of the resistor 22, and the resistor 23 is further formed.
By forming the good thermal conductive film 25 on the back surface of the insulating substrate 21 on which the ridges are formed, then dividing into individual chip resistors, and forming the end face electrodes 26 on both side face portions, the chip resistor as shown in FIG. I have a good vessel.

[0007]

However, in the structure of the chip resistor using the 96 wt% alumina substrate as the insulating substrate as described above, the hardness of the insulating substrate is high, and the dividing slit is formed after sintering. Therefore, an alumina substrate sintered with slits for division at the green sheet stage is used as an insulating substrate.Therefore, the dimensional variation of the insulating substrate increases due to the sintering, and the dimensions for manufacturing a chip resistor are increased. There is a problem in that a large number of electrodes, resistors and print masks for protective films must be prepared in consideration of variations.

In order to solve such a problem, a glass ceramic substrate is used as an insulating substrate so that a resistor or a protective film is formed on the insulating substrate and then a dividing groove is formed so as to be divided into individual chip resistors. Although it can be considered to be used, the glass ceramic substrate mixed with ceramic powder to the extent that the dividing grooves can be formed after sintering has poor thermal conductivity, and the heat generated by the resistor is the heat from the end face electrodes on both sides to the circuit board. There is a limit to using a chip resistor with high power because the heat is dissipated by transmission and the amount of heat dissipation is small,
In order to deal with this, there is a problem that the size of the chip resistor must be increased.

Therefore, in order to improve the heat dissipation of the chip resistor, the technical means disclosed in the above publication is applied,
It is conceivable to form a good thermal conductive film on the center of the lower surface of the insulating substrate.In such a structure, when the chip resistor is mounted on the circuit board, the solder contacts the good thermal conductive film and the desired resistance There is a problem that it may not be possible to obtain a value, and in the case of an insulating substrate with low thermal conductivity, simply forming a good thermal conductive film in the center of the lower surface of the insulating substrate provides insulation when using chip resistors at high power. There is a problem that the heat dissipation of the heat generated by the resistor on the upper surface of the substrate is insufficient.

As described above, in the conventional chip resistor, the manufacturing control cost thereof increases due to the dimensional variation of the insulating substrate, or the chip resistor is caused by the heat of the resistor due to insufficient heat dissipation. There was a problem that the performance of could deteriorate.

In view of the above-mentioned conventional problems, it is an object of the present invention to provide a method of manufacturing a chip resistor which can manufacture the chip resistor with high dimensional accuracy and high reliability, and its structure.

[0012]

According to a first aspect of the present invention, there is provided a method of manufacturing a chip resistor, comprising: a first glass ceramic green sheet containing a first powder of ceramic powder; A step of producing a second glass-ceramic green sheet containing a second amount of ceramic powder, a step of laminating the first and second glass-ceramic green sheets, and a step of sintering the green sheet laminate to obtain a thickness. Of obtaining an insulating substrate having anisotropic heat conduction having a distribution of thermal conductivity in the direction, forming an electrode, a resistor and a protective film on the surface of the insulating substrate having high thermal conductivity, and conducting the heat conduction of the insulating substrate. And a step of forming a dividing groove on a surface having low property and dividing into a desired size.

A method of manufacturing a chip resistor according to a second aspect of the present invention is the first method including the ceramic powder having the first thermal conductivity.
And a second glass ceramic green sheet containing a ceramic powder having a second thermal conductivity higher than the first thermal conductivity, and a first and a second glass ceramic. The steps of laminating the green sheets, the step of sintering the green sheet laminate to obtain an insulating substrate having thermal conductivity anisotropy having a distribution of thermal conductivity in the thickness direction, and the step of increasing the thermal conductivity of the insulating substrate. The method is characterized by including a step of forming an electrode, a resistor, and a protective film, and a step of forming a dividing groove on a surface of the insulating substrate having low thermal conductivity to divide the insulating substrate into a desired size.

In the structure of the chip resistor of the third invention of the present application, a glass ceramic is used for the insulating substrate, the insulating substrate is anisotropic in heat conduction having a distribution of heat conductivity in the thickness direction, and the heat conduction of the insulating substrate. It is characterized in that it is provided with an electrode, a resistor and a protective film formed on a highly flexible surface, and end face electrodes formed on both side surfaces of the insulating substrate.

[0015]

According to the present invention, the glass ceramic substrate is used as the insulating substrate of the chip resistor, and after the resistor or the protective film is formed on one surface of the insulating substrate, the thermal conductivity of the other surface of the insulating substrate is reduced. Since the dividing groove is formed on the surface of which relatively low hardness can be achieved, it is possible to divide into a desired size with high dimensional accuracy, so that the manufacturing management cost of the chip resistor can be reduced. Moreover, since the insulating substrate having the thermal conductivity anisotropy having the distribution of the thermal conductivity in the thickness direction is configured and used, and the resistor is formed on the surface of the insulating substrate having the high thermal conductivity, the chip resistance is high. Even when using a resistor, it is possible to satisfactorily dissipate the heat generated by the resistor on the upper surface of the insulating substrate having anisotropy of heat conduction, and it is possible to realize a chip resistor with high reliability.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a chip resistor according to a first embodiment of the present invention and its structure will be described below with reference to FIGS.

1 and 2, 1 is a first glass ceramic green sheet containing 50% by weight of alumina powder, 2 is a second glass ceramic green sheet containing 90% by weight of alumina powder, and 3 is a stack of green sheets. A body, 4 is an insulating substrate having anisotropic heat conduction, 5 is an electrode, 6 is a resistor, 7 is a protective film, and 8 is an end face electrode.

Next, the manufacturing process of the chip resistor having the structure shown in FIG. 2 will be described with reference to FIG.

First, as shown in (a), a first glass ceramic green sheet 1 containing 50% by weight of alumina powder and a second glass ceramic green sheet 2 containing 90% by weight of alumina powder are prepared in advance.

At this time, a lead borosilicate glass powder and an alumina powder were mixed in a weight ratio of 10:90, an inorganic component was polyvinyl butyral, and a plasticizer was di-
n-butyl phthalate, a mixed solution of toluene and isopropyl alcohol (weight ratio 30:70) as a solvent were mixed to form a slurry, and the slurry was formed into a sheet on an organic film by a doctor blade method and dried,
A second glass ceramic green sheet 2 containing 90% by weight of alumina powder was used.

Similarly, the first glass ceramic containing 50% by weight of alumina powder was produced by the above method using the inorganic component in which the weight ratio of lead borosilicate glass powder and alumina powder was 50:50. It was used as green sheet 1.

Next, as shown in (b), a second glass ceramic green sheet 2 containing 90% by weight of alumina powder and a first glass ceramic green sheet 1 containing 50% by weight of alumina powder are stacked and thermocompression bonded. Then, a green sheet laminate 3 was obtained.

The thermocompression bonding conditions are a temperature of 80 ° C. and a pressure of 2
It was 00 kg / cm ² .

Thereafter, as shown in (c), the green sheet laminate 3 was sintered in a belt furnace to obtain an insulating substrate 4 having anisotropic heat conduction. Sintering conditions are 1300 ° C and 1
(1300 ° C. hold time is about 10 minutes).

The thus obtained insulating substrate 4 having anisotropic heat conduction has a high heat conductivity because it contains a large amount of alumina (the heat conductivity when containing 90% by weight of alumina is 0.0).
4cal / cm · sec · ° C), which has a lower thermal conductivity because the amount of alumina is less than that of the surface (50% for alumina).
Thermal conductivity is 0.007 cal / cm when it contains wt%
.Sec..degree. C.) and has a distribution of thermal conductivity in the thickness direction. The surface having a low thermal conductivity has a low hardness because it contains a large amount of glass, and the surface has a higher hardness than that and can be easily ground by a processing blade having a sharp angle shape.

Then, as shown in (d), a predetermined electrode pattern is formed on the surface of the insulating substrate 4 having the thermal conduction anisotropy having a high thermal conductivity by using a conductive paste containing silver-palladium as a main component. After printing, the electrode 5 is formed by firing at a firing temperature of 850 ° C. Furthermore, after a resistor pattern corresponding to the electrode 5 is printed using a resistance paste containing ruthenium oxide as a main component, the resistor 6 is fired at a firing temperature of 850 ° C. Further, after forming a protective film pattern corresponding to the resistor 6 using a glass paste containing glass as a main component, the protective film 7 is formed by baking at a baking temperature of 650 ° C. Thus, the insulating substrate 4 having the heat conduction anisotropy, in which the electrodes 5, the resistors 6 and the protective film 7 corresponding to the plurality of chip resistors are formed, is obtained.

Next, a dividing groove for dividing into individual chip resistors is formed on the surface of the insulating substrate 4 having the thermal conduction anisotropy having a low thermal conductivity, which has a hardness higher than the hardness and a sharp angle shape. After being formed by a machining blade having a groove, by applying mechanical stress evenly on a rubber plate having elasticity, as shown in (e), individual chip resistors with desired dimensions and good dimensional accuracy can be obtained. You get a bowl.

At the time of forming the dividing groove, a rotating blade made of diamond having an abacus ball shape is used to form 0.5 to
Grinding was performed while rotating the surface of the insulating substrate 4 having thermal conductivity anisotropy while applying a pressure of 1.0 kg / cm ² . At this time, a division groove having a depth of several microns could be formed on the surface of the insulating substrate 4 having the thermal conductivity anisotropy by the rotary working blade. The tip of the rotary processing blade was processed to 130 °.

Finally, as shown in (f), by forming the end face electrodes 8 on both side faces of the individually divided chip resistors, heat conduction having a distribution of heat conductivity in the thickness direction shown in FIG. A chip resistor in which an insulating substrate 4 having anisotropy, an electrode 5, a resistor 6 and a protective film 7 on its upper surface and end surface electrodes 8 on both side surfaces are formed is obtained.

In the thus obtained chip resistor, the surface on which the resistor 6 is formed has a high thermal conductivity because it contains a large amount of alumina, and even when the chip resistor is used at high power, it is generated by the resistor. The heat dissipation is good, and a chip resistor with high performance reliability can be realized.

In this embodiment, alumina is used as the ceramic powder of glass ceramic, but any material having good thermal conductivity such as aluminum nitride or silicon carbide may be used.

Next, a method of manufacturing the chip resistor according to the second embodiment of the present invention will be described with reference to FIGS.

In FIG. 3, first, as shown in (a),
First glass ceramic green sheet 11 containing 50% by weight of alumina powder and second glass ceramic green sheet 12 containing 50% by weight of silicon carbide powder are prepared in advance.

At this time, an inorganic component having a weight ratio of lead borosilicate glass powder and silicon carbide powder of 50:50, polyvinyl butyral as an organic binder, and di-
n-butyl phthalate, a mixed solution of toluene and isopropyl alcohol (weight ratio 30:70) as a solvent were mixed to form a slurry, and the slurry was formed into a sheet on an organic film by a doctor blade method and dried,
It was used as the second glass ceramic green sheet 12 containing 50% by weight of silicon carbide powder.

Similarly, the first glass ceramic green containing 50% by weight of alumina powder was produced by the above method using an inorganic component in which the weight ratio of lead borosilicate glass powder and alumina powder was 50:50. It was used as sheet 11.

Next, as shown in (b), the second glass ceramic green sheet 12 containing 50% by weight of silicon carbide powder and the first glass ceramic green sheet 11 containing 50% by weight of alumina powder are stacked and heated. A green sheet laminate 13 was obtained by pressure bonding. The thermocompression bonding conditions were a temperature of 80 ° C. and a pressure of 200 kg / cm ² .

Thereafter, as shown in (c), the green sheet laminate 13 was sintered in a belt furnace to obtain an insulating substrate 14 having anisotropic heat conduction. The sintering condition was 900 ° C. for 1 hour (holding time at 900 ° C. was about 10 minutes).

Insulating substrate 14 having anisotropic heat conduction thus obtained
In order to contain silicon carbide having high thermal conductivity, the surface having high thermal conductivity (the thermal conductivity when silicon carbide is contained at 50% by weight is 0.1 cal / cm · sec · ° C), Since it contains alumina having a lower thermal conductivity than the above, the surface having a low thermal conductivity (the thermal conductivity in the case of including 50% by weight of alumina is 0.007 cal / cm · sec · ° C) is included.
It has a distribution of thermal conductivity in its thickness direction. The insulating substrate 14 having thermal conductivity has a low hardness because it contains a large amount of glass, and has a hardness higher than the hardness and can be easily ground by a processing blade having a sharp angled shape.

Then, as shown in (d), the surface of the insulating substrate 14 having the thermal conduction anisotropy having high thermal conductivity has silver-
A predetermined electrode pattern is printed using a conductive paste containing palladium as a main component, and then baked at a baking temperature of 850 ° C. to form the electrode 15. Furthermore, after a resistor pattern corresponding to the electrode 15 is printed using a resistance paste containing ruthenium oxide as a main component, the resistor 16 is formed by firing at a firing temperature of 850 ° C. In addition, after forming a protective film pattern corresponding to the resistor 16 using a glass paste containing glass as a main component, the protective film 17 is formed by firing at a firing temperature of 650 ° C. Thus, the insulating substrate 1 having the heat conduction anisotropy, in which the electrodes 15, the resistors 16 and the protective film 17 corresponding to the plurality of chip resistors are formed.
4 is obtained.

Next, a dividing groove for dividing into individual chip resistors is formed on the insulating substrate 14 having the heat conduction anisotropy by a processing blade having a hardness higher than that and having a sharp angle shape. After that, by uniformly applying mechanical stress on an elastic rubber plate or the like, as shown in (e), individual chip resistors having desired dimensions and good dimensional accuracy can be obtained.

At the time of forming the dividing grooves, a diamond rotary machining blade having the shape of an abacus ball is used to form 0.5 to 0.5
The surface of the insulating substrate 14 having the thermal conductivity anisotropy was ground while rotating while applying a pressure of 1.0 kg / cm ² . In this way, the dividing groove having a depth of several microns could be formed on the surface of the insulating substrate 4 having the thermal conductivity anisotropy by the rotary working blade. The tip of the rotary processing blade was processed to 130 °.

Finally, as shown in (f), the end face electrodes 18 are formed on both side faces of the individually divided chip resistors, so that the heat conduction having the distribution of heat conductance in the thickness direction shown in FIG. 4 is obtained. It is possible to obtain a chip resistor in which the insulating substrate 14 having anisotropy, the electrode 15, the resistor 16 and the protective film 17 on the upper surface thereof and the end surface electrodes 18 on both side surfaces are formed.

In the thus obtained chip resistor, the surface on which the resistor 16 is formed has high thermal conductivity because it contains silicon carbide having high thermal conductivity, and even when the chip resistor is used at high power. The heat dissipation of the heat generated by the resistor is improved, and a chip resistor having high performance reliability can be realized.

In this embodiment, alumina and silicon carbide are used as the ceramic powder of the glass ceramic, but any material having good thermal conductivity such as aluminum nitride may be used.

[0045]

According to the method of manufacturing a chip resistor of the present invention, the chip resistor has a high dimensional configuration and can satisfactorily dissipate the heat generated by the resistor even when the chip resistor is used with high power. It is possible to obtain a chip resistor having high reliability.

The structure of the chip resistor of the present invention is
Even when the chip resistor is used at high power, the heat dissipation of the heat generated by the resistor is good, and the chip resistor with high performance reliability can be realized.

[Brief description of drawings]

FIG. 1 is a process drawing of a method of manufacturing a chip resistor according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the chip resistor of the same example.

FIG. 3 is a process drawing of the method of manufacturing the chip resistor according to the second embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of the chip resistor of the same example.

FIG. 5 is a vertical cross-sectional view of a conventional chip resistor.

[Explanation of symbols]

 1 First Glass-Ceramic Green Sheet 2 Second Glass-Ceramic Green Sheet 3 Laminate of Green Sheets 4 Insulating Substrate with Thermal Conduction Anisotropy 5 Electrode 6 Resistor 7 Protective Film 8 End Surface Electrode 11 First Glass-Ceramic Green Sheet 12 Second glass-ceramic green sheet 13 Green sheet laminate 14 Thermally conductive anisotropic insulating substrate 15 Electrode 16 Resistor 17 Protective film 18 Edge electrode

Claims (5)

[Claims] 1. A first glass-ceramic green sheet containing a first blending amount of ceramic powder, and a second glass-ceramic green sheet containing a second blending amount of ceramic powder that is larger than the first blending amount. And a step of producing
A step of laminating the first and second glass ceramic green sheets, a step of sintering the green sheet laminated body to obtain a thermally conductive anisotropic insulating substrate having a thermal conductivity distribution in the thickness direction, and an insulating substrate And a step of forming an electrode, a resistor and a protective film on the surface of high thermal conductivity of the insulating substrate, and a step of forming a dividing groove on the surface of the insulating substrate having low thermal conductivity and dividing into a desired size. A method of manufacturing a chip resistor. 2. A first glass-ceramic green sheet containing a ceramic powder having a first thermal conductivity;
A second glass-ceramic green sheet containing a ceramic powder having a second thermal conductivity higher than that of, a step of laminating the first and second glass-ceramic green sheets, and a green Sintering the sheet laminated body to obtain an insulating substrate having thermal conductivity anisotropy having a thermal conductivity distribution in the thickness direction, and forming an electrode, a resistor and a protective film on the surface of the insulating substrate having high thermal conductivity. And a step of forming a dividing groove on a surface of the insulating substrate having a low thermal conductivity to divide the insulating substrate into a desired size. 3. The method of manufacturing a chip resistor according to claim 1, wherein the ceramic powder contains powder of alumina, aluminum nitride or silicon carbide. 4. The method of manufacturing a chip resistor according to claim 1, wherein the dividing groove is formed by a processing blade having a hardness higher than that of the insulating substrate and having a sharp angled shape. 5. An insulating substrate having a heat conduction anisotropy having a distribution of thermal conductivity in the thickness direction, using a glass ceramic as the insulating substrate, an electrode and a resistor formed on a surface of the insulating substrate having high thermal conductivity, and 1. A chip resistor structure comprising a protective film and end face electrodes formed on both sides of an insulating substrate.