JP2935143B2 - Square chip resistor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectangular chip resistor for a vehicle, a consumer device, or an industrial device, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are a sectional view and a perspective view, respectively, showing a main part of a conventional square chip resistor. This square chip resistor is provided at both ends of the alumina ceramic substrate 1.
An electrode portion 9 having a U-shaped cross section that covers the upper surface, the side surface, and the back surface is formed. In the electrode section 9, the upper surface of the substrate 1 is the primary electrode 2, the side surface of the substrate 1 is the secondary electrode 2a, and the rear surface of the substrate 1 is the tertiary electrode 3. Further, the substrate 1
A resistance portion 5 is formed so as to extend between the primary electrodes 2 and 2 formed at both ends of the upper surface of the substrate.

The electrode section 9 forms a thick-film conductive layer 91 with a thick-film conductor paste (Ag paste) over the upper end, the side, and the rear end of the substrate 1, that is, in a U-shaped cross section. A Ni plating film 92 is formed on the upper surface of the thick film conductive layer 91, and a Pb-Sn plating film 93 is further formed on the upper surface of the Ni plating film 92 to form a three-layer structure. Then, primary electrodes (thick film conductive layer 9) at both ends of the upper surface of alumina ceramic substrate 1 are formed.
1) A resistive film (paste mainly composed of Ru and lead borosilicate glass) 51 is printed and baked over 2 and a primary protective film (thick glass) 52 and a primary protective film are formed on the upper surface of the resistive film 51. Membrane 52
Protective film (thick film) 53, secondary protective film 5
The protective outer film (thick film glass) 54 is printed and baked on the upper surface of each of the light-emitting devices 3 and manufactured.

[0004]

As shown in FIG. 3, the conventional square chip resistor is mounted on a conductor pattern 7 of, for example, a glass epoxy wiring board (the tertiary electrode 3 is placed on the conductor pattern 7). On the primary electrode 2 and the side electrode 2
The solder 8 is piled up and fixed on the conductor pattern 7 and the conductor pattern 7. Since the electrode portion is solder-plated, the solder is applied to the entire electrode portion at the time of soldering, not only when the number of the solders 8 is large but also when the number is small. However, the expansion and contraction rate with respect to the temperature of the solder is much larger than the expansion and contraction rate with respect to the temperature of the thick film conductor layer 91 constituting the electrode portion 9.
Therefore, the temperature difference (−55 ° C. to 125 ° C., 100 ° C.)
0 to 3000 cycles), mechanical stress concentration such as the thick-film conductor layer 91 being pulled by the solder portion occurs, and the thick-film conductor layer 91 becomes alumina near the boundary between the primary electrode 2 and the secondary protective film 53. There are disadvantages such as peeling from the ceramic substrate 1 and disconnection.

In addition, the conventional square chip resistor has disadvantages in that the secondary electrodes (side electrodes) 2a must be formed on both side surfaces of the insulating substrate 1 and the production is troublesome.

[0006] The present invention solves the above problems,
It is an object of the present invention to provide a square chip resistor which is easy to manufacture and has no risk of disconnection due to peeling of a thick film conductor layer from a substrate due to a temperature change, and a method of manufacturing the same.

[0007]

In order to attain this object, a square chip resistor according to claim 1 of the present invention has an insulating substrate having a through hole penetrating an electrode forming portion. And electrodes formed at both ends of the upper surface of the insulating substrate, a resistance portion formed across the electrodes on the upper surface of the insulating substrate, and inserted into the through-hole, and connected to the electrodes on the upper surface of the insulating substrate. An electrode fitting having a flat plate portion in contact with and a flat plate portion in contact with the lower surface of the insulating substrate is provided.

In this rectangular chip resistor, two
The electrode (primary electrode) is formed only on the upper surface of the insulating substrate without forming the next electrode (side electrode). Then, by inserting the electrode fitting into the through hole, the shaft of the electrode fitting is inserted into the through hole, and one flat part of the electrode fitting comes into contact with the electrode on the upper surface of the insulating substrate, and the other flat part is insulated. Contact the lower surface of the substrate. As a result, one flat plate portion is located at both end portions (primary electrode forming portions) of the upper surface of the insulating substrate, and the other flat plate portion is located at both end portions (tertiary electrode forming portion) of the lower surface of the insulating substrate, The electrode on the upper surface of the insulating substrate is electrically connected to the flat plate on the lower surface of the insulating substrate through the electrode fitting. That is, the electrode fittings have both functions of the primary electrode and the tertiary electrode.

Thus, when the square chip resistor is placed on the conductor pattern of the wiring board (the flat plate portion of the electrode fitting as the tertiary electrode is placed on the conductor pattern) and is fixed by soldering, This can be performed by interposing an adhesive solder only between the conductor pattern and the flat plate portion. Therefore, it is not necessary to perform solder embossing on the flat plate portion of the electrode fitting as the primary electrode, so that mechanical stress concentration due to the difference between the coefficient of thermal expansion of the solder and the coefficient of thermal expansion of the electrode can be avoided, and the risk of disconnection can be eliminated. .

According to a second aspect of the present invention, there is provided a method of manufacturing a square chip resistor, comprising the steps of forming through holes at both ends of an insulating substrate, and forming the through holes on the upper surface of the insulating substrate corresponding to the through holes. A step of forming a thick film conductor layer, a step of forming a resistance portion over the thick film conductor layer on the upper surface of the insulating substrate, a shaft portion inserted into the through hole, and two ends of the shaft portion. The shaft portion of the electrode fitting having a flat portion provided in a direction perpendicular to the extending direction of the shaft portion is fitted into the through hole, and one flat portion is brought into contact with the thick film conductor layer on the upper surface of the insulating substrate. Contacting the other flat portion with the lower surface of the insulating substrate.

In this method of manufacturing a rectangular chip resistor, if an electrode fitting is attached to a through hole formed in an insulating substrate, one flat plate portion of the electrode fitting contacts an electrode on the upper surface of the insulating substrate,
The other flat portion contacts the lower surface of the insulating substrate. That is, one flat plate portion of the electrode fitting functions as a primary electrode, and the other flat plate portion functions as a tertiary electrode. Therefore, the step of forming the secondary electrode (side electrode) on the insulating substrate can be omitted, and the manufacturing can be simplified and the cost can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a square chip resistor according to the present invention will be described based on embodiments.

FIG. 1 is a cross-sectional view of a main part of a rectangular chip resistor according to one embodiment, and FIG. 2 is a cross-sectional perspective view of the main part. The square chip resistor includes an alumina ceramic substrate 1 having through holes 4 penetrating both ends (electrode forming portions), and primary electrodes (surface electrodes) formed on both ends of an upper surface of the substrate 1. Thick film conductor layer 21)
And a resistance part 5 formed so as to extend between the thick film conductor layers 21 and 21, and electrode fittings 6 and 6 respectively fitted in the through holes 4 and 4.

The resistance portion 5 includes a resistance film 51 formed over the thick film conductor layers 21 and 21, an internal protection film (primary protection film) 52 formed on the resistance film 51, Protective film 52
And a secondary protection film 53 formed thereon.
Is formed with a laser trimming groove 51a, and the resistance value is adjusted. Further, the resistance portion 5 is covered with a protective sheathing film 54, and the protective sheathing film 54 is marked with a mark such as a resistance value display.

Here, the electrode fitting 6 has an I-shaped cross section composed of an upper fitting 61 and a lower fitting 62. The upper metal fitting 61 includes a flat plate portion 61 a having a constant width length (a width length corresponding to the thick film conductor layer 21), and a flat plate portion 61.
a short cylindrical portion 61b protruding in the plane of a corresponding to the through hole 4
Consists of The lower metal fitting 62 includes a flat plate portion 62a having a constant width and a length, and a shaft portion 62b protruding from the flat plate portion 62a so as to be fitted to the short cylindrical portion 61b. Upper bracket 6
1 and the lower metal fitting 62 are fitted, the flat plate portion 61 a of the upper metal fitting 61 contacts the thick film conductor layer 21, and the lower metal fitting 62.
Contact the lower surface of the substrate 1. Therefore, the thick film conductor layer 21 is electrically connected to the flat plate portion 62a through the upper metal fitting 61 and the lower metal fitting 62, and the flat plate portion 61a functions as a primary electrode and the flat plate portion 62a functions as a tertiary electrode.

The square chip resistor is manufactured by the following steps. First, through holes 4 penetrating the substrate 1 are formed in advance at both ends of the alumina ceramic substrate 1, that is, at portions where the electrode portions are to be formed. Then, Ag is provided on both ends of the upper surface of the substrate 1 corresponding to the through holes 4 respectively.
-The thick film conductor layer 21 is formed from Pd or Ag paste. Next, the resistance portion 5 is formed so as to extend between the thick film conductor layers 21 and 21 formed on both ends of the upper surface of the alumina ceramic substrate 1. In the resistance section 5, a resistance film (paste mainly composed of Ag-Pd, Ru and lead borosilicate glass) 51 is printed and fired across the thick film conductor layers 21 and 21. The resistance value of the resistance film 51 is adjusted by forming a laser trimming groove 51a at an appropriate position. Then, on the upper surface of the resistive film 51, an internal protective film (primary protective film) using a glass paste.
52 is printed and baked, and a secondary protective film 53 is printed and baked on the upper surface of the internal protective film 52. After that, the protective exterior film 54 is printed and baked on the upper surface of the resistor portion 5 (that is, the secondary protective film 53), and a mark such as a resistance value display is formed on the protective exterior film 54 by thick film printing.

Next, a chip break is performed on each chip product from a substrate in which a large number of chip resistors are connected. After the break, in each chip product, of the electrode fittings 6, the shaft portion 62b of the lower metal fitting 62 is inserted into the through-hole 4, and the short cylindrical portion 61b of the upper metal fitting 61 is inserted into the through-hole from the upper surface side of the thick film conductor layer 21. 4 and the shaft portion 62b is fitted into the short cylindrical portion 61b and swaged. Thus, an electrode portion in which the upper metal fitting 61 and the lower metal fitting 62 are integrally connected is formed, and a completed rectangular chip resistor is obtained.

In the rectangular chip resistor manufactured as described above, the secondary electrode (side surface electrode) is not formed on the substrate 1 and only the thick film conductor layer 21 as the primary electrode is formed. If the metal fitting 6 is fitted, the thick film conductor layer 21 and the upper metal fitting 6
The first flat plate portion 61a contacts the flat plate portion 62 of the lower metal fitting 62.
a contacts the lower surface of the substrate 1. Therefore, when this square chip resistor is placed on the conductor pattern 7 of the wiring board (the flat plate portion 62a is placed on the conductor pattern 7) and fixed by soldering 8, the conductor pattern 7 and the flat plate portion 62a This can be performed by interposing the adhesive solder 8 only between the two. Thereby, the thick film conductor layer 21, that is, the flat plate portion 61 of the upper metal fitting 61 is formed.
It is not necessary to perform solder embossing on a, mechanical stress concentration due to the difference between the thermal expansion coefficient of the solder and the thermal expansion coefficient of the thick film conductor layer 21 can be avoided, and the risk of disconnection can be eliminated.

In this method of manufacturing a square chip resistor, an electrode portion is formed by attaching an electrode fitting 6 to the through hole 4 of the substrate 1, so that a step of forming a secondary electrode (side electrode) is omitted. Can be manufactured easily and cost can be reduced.

[0020]

As described above, according to the rectangular chip resistor of the present invention, the electrode fitting is fitted into the through hole of the insulating substrate, and the flat plate portion is used as the primary electrode and the secondary electrode. Therefore, since no electrodes are formed on the chip side portion, when connecting the external conductor pattern and the resistor, soldering is performed on the flat plate portion of the electrode fitting that contacts the electrode on the upper surface of the insulating substrate as a primary electrode. It is not necessary, and since the solder does not rest on the flat part of the electrode on the upper surface via the solder plating part, mechanical stress concentration due to the difference between the thermal expansion coefficient of the solder and the thermal expansion coefficient of the electrode is avoided, The risk of disconnection can be eliminated.

Further, according to the method of manufacturing the square chip resistor of the present invention, the step of forming the secondary electrode (side electrode) can be omitted, and the manufacturing can be simplified and the cost can be reduced. The plating process can be omitted, and complicated liquid management for plating and expensive plating equipment are not required.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a square chip resistor according to an embodiment.

FIG. 2 is a sectional perspective view of a main part of the rectangular chip resistor according to the embodiment.

FIG. 3 is a sectional view of a main part of a rectangular chip resistor according to a conventional example.

FIG. 4 is an external perspective view of a square chip resistor according to the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 4 Through-hole 5 Resistance part 6 Electrode fitting 7 Conductor pattern 8 Solder 21 Thick film conductor layer 61 Upper metal fitting 62 Lower metal fitting 61a, 62a Flat plate part 61b Short cylinder part 62b Shaft part

Claims (2)

(57) [Claims] An insulating substrate having a through hole penetrating the electrode forming portion; and an insulating substrate formed at both ends of an upper surface of the insulating substrate.
And electrodes were formed straddling between the electrodes on the upper surface of the insulating substrate
A resistance portion, and a power supply electrode on the upper surface of the insulating substrate, which is inserted into the through hole.
A flat plate part that contacts the pole and a flat plate that contacts the lower surface of the insulating substrate
And an electrode fitting having a portion . Wherein the step of forming the respective through-holes on both ends of the insulating substrate, the upper surface of the insulating substrate corresponding to the through hole Niso
Forming a respectively thick film conductor layer, the upper surface of the insulating substrate
Forming a resistor portion over the thick film conductor layer;
A shaft portion inserted into the through-hole and extension of the shaft portion at both ends of the shaft portion.
An electrode having a flat portion provided in a direction perpendicular to the stretching direction
Insert the shaft of the metal fitting into the through hole, and
Contact the thick conductor layer on the top surface of the insulating substrate, and
Contacting the plate portion with the lower surface of the insulating substrate.
A method for manufacturing a square chip resistor, comprising: