JPH05135902A - Rectangular chip resistor and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] [Purpose] In a rectangular chip resistor having a glass layer on the top and back surfaces that is used as a substitute for a cylindrical rectangular chip resistor, sufficient bonding strength can be obtained even when mounted on the side, and the glass on the back surface is also provided. The softening point is set to be higher than the firing temperature of the upper surface glass and the firing temperature of the end face electrodes to simplify the manufacturing process. [Structure] The length in the thickness direction is 80% to 1 of the length in the width direction.
20% of the 96 alumina substrate 1, the upper surfaces of both main surfaces of the 96 alumina substrate 1, the back surface electrode layers 2 and 3, the resistance layer 4 overlapping a part of the upper surface electrode layer 2, and the softening point of 550 ° C. to 580 ° C.
Of the first glass layer 5, the second glass layer 6 having a softening point of 630 ° C. to 850 ° C., the end face electrode layer 7 connecting the upper face and the back face electrode layers 2 and 3, and the end face electrode 7 layer were formed at the same time. First
The side surface electrode layer 10 and the second side surface electrode layer 11 are provided.

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 as an alternative to a cylindrical chip resistor mounted by a collective mounting machine of cylindrical chip resistors used in a high-density wiring circuit, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, with the ever-increasing demand for smaller, lighter, smaller electronic devices, in order to increase the wiring density of circuit boards, very small rectangular chip resistors are often used as resistive elements. Has become. Further, in recent years, in order to increase the mounting speed, collective mounting for mounting a large number of chip components at the same time has been performed.

FIG. 5 shows an example of the structure of a rectangular chip resistor mounted by a conventional thick film type cylindrical chip resistor package mounting machine.

A rectangular chip resistor mounted by a conventional packager of cylindrical chip resistors is a rectangular plate-shaped insulation whose length in the thickness direction is 80% to 120% of the length in the width direction. 96 alumina substrate 20, a top electrode layer 21 formed of a pair of thick film electrodes formed on the main surface of the 96 alumina substrate 20, and a ruthenium-based thick film formed so as to be connected to the top electrode layer 21. The resistance layer 22 due to resistance and the first glass layer 2 having a softening point covering the resistance layer of 550 ° C. to 580 ° C.
4 and the back surface electrode layer 27 on the back surface of the 96-alumina substrate 20 and the softening point overlapping a part of the back surface electrode layer 27 at 550 ° C.
It is composed of a second glass layer 28 at 580 ° C. and an end face electrode layer 23 that overlaps a part of the upper face electrode layer 21, and a Ni plating layer 25 is formed on the exposed electrode face in order to secure solderability.
And the solder plating layer 26 are formed by electrolytic plating.

The manufacturing method of this rectangular chip resistor has been performed according to the flow shown in FIG.

[0006]

However, in the conventional rectangular chip resistor, when the above-mentioned collective mounting is performed, when the components are mounted, the rectangular chip resistor 30 as shown in FIG.
May be mounted not on the main surface of the board but on the side surface side. If mounted in this way, the area of the electrode portion 29 that comes into contact with the printed board is small, and the area to be soldered is reduced, so that sufficient fixation is achieved. It had a defect that strength could not be obtained.

Further, in the conventional rectangular chip resistor, the softening point (550 ° C. to 580 ° C.) of the same degree is applied to the first protective layer and the second protective layer.
Since the glass having a temperature of (.degree. C.) is used, the manufactured product 52 is placed on the jig 53 and floated from the conveyor belt 51 of the baking furnace as shown in FIG. 7 when baking the glass and as shown in FIG. 8 when baking the end face electrodes. Since it has to be fired, the construction process of the rectangular chip resistor becomes complicated as shown in FIG. 9 (especially, a man-hour is required to set the strip-shaped product 52 of FIG. 8), and the production cost is high. There was a problem of up.

The present invention solves all such problems at once, and provides a rectangular chip resistor having a sufficient fixing strength even if the rectangular chip resistor is mounted on the side surface and having a simple manufacturing process. The purpose is to do.

[0009]

In order to achieve the above object, the present invention has a length in the thickness direction of 80% of the length in the width direction.
A rectangular plate-shaped insulating sintered substrate having a length of 120%, a pair of upper surface electrode layers formed on one main surface of the sintered substrate, and a part of the pair of upper surface electrode layers. The overlapping resistive layer, the first glass layer having a softening point of 550 ° C. to 580 ° C. that completely covers the resistive layer, the pair of back surface electrode layers on the other main surface of the sintered substrate, and the back surface electrode layer. 6 softening points
A second glass layer at 30 ° C. to 850 ° C., a pair of end face electrode layers electrically connecting the pair of upper face electrode layers and a pair of back face electrode layers, and the upper face electrode layer and the end face on two side faces From two pairs of first side surface electrode layers that electrically connect to the electrode layers, and two pairs of second side surface electrode layers that also electrically connect the back surface electrode layer and the end surface electrode layer on two side surfaces. Composed.

As a manufacturing method thereof, the second glass layer is formed by firing at a temperature of 700 ° C. to 950 ° C.,
After firing the second glass layer, the first glass layer is heated to 550 ° C.
It is formed by firing at a temperature of ~ 660 ° C, and the first
After firing the glass layer, a pair of end surface electrode layers, two pairs of first side surface electrode layers and two pairs of second side surface electrode layers were formed at 550 ° C to 660 ° C.
It is baked at the temperature of.

[0011]

According to the present invention, even if the rectangular chip resistor is mounted on the side surface, it is soldered to the first side surface electrode layer and the second side surface electrode layer on the side surface portion. Therefore, the area of the electrode portion contacting the printed circuit board is reduced. Becomes large, and sufficient fixing strength can be obtained.

The second softening point of 630 ° C to 850 ° C
The glass layer is fired at a temperature of 700 ° C. to 950 ° C., and thereafter, the second glass layer is brought into contact with the conveyor belt so that the second glass layer is heated to a temperature of 550 ° C. to 620 ° C. which is lower than the softening point of the second glass layer. One glass layer is fired, and after the first glass layer is fired, the softening point of the second glass layer is 550 ° C. to 660 in the same manner.
By baking the end face electrode layer at a temperature of ℃, it is not necessary to float the manufactured product above the conveyor belt of the baking furnace when baking glass and end face electrode layers, and the manufacturing process of the rectangular chip resistor is simplified. Is done.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rectangular chip resistor according to an embodiment of the present invention and a method of manufacturing the same will be described below with reference to the drawings.

FIGS. 1A and 1B are a perspective view and a sectional view showing the present embodiment. In FIG. 1, the rectangular chip resistor according to the present embodiment has a length in the thickness direction of 80 in the width direction.
% To 120% of a rectangular plate-shaped insulating 96 alumina substrate 1, a pair of silver-based thick film upper surface electrode layers 2 on one main surface of the 96 alumina substrate 1, and the 96 alumina substrate. Of the back surface electrode layer 3 on the other main surface, a resistance layer 4 of a ruthenium-based thick film that overlaps a part of the top surface electrode layer 2, and a softening point that completely covers the resistance layer 4 is 560 ± 5 ° C. 1 glass layer 5
And the softening point overlapping a part of the back electrode layer 3 is 680 ±
A second glass layer 6 at 5 ° C., an end face electrode layer 7 of a silver-based thick film that partially overlaps the top face electrode layer 2 and the back face electrode layer 3, and a top face electrode layer 2 and an end face electrode layer 7. 1 side electrode layer 1
0, and the second side surface electrode layer 11 connected to the back surface electrode layer 3 and the end surface electrode layer 8. In order to improve solderability on the exposed electrode surface, the Ni plating layer 8 and Sn were used.
-Pb plating layer 9 is applied by electrolytic plating.

Next, a method of manufacturing the rectangular chip resistor of this embodiment shown in FIG. 1 will be described with reference to FIG. First, the 96 alumina substrate 1 having excellent heat resistance and insulating properties is received. In order to divide the 96 alumina substrate 1 into strips and individual pieces, a dividing groove (molding at the time of green sheet) is formed (the thickness of the substrate is 0.6).
35 mm, the grooves for division are formed with a pitch of 1.5 mm and 0.8 mm. ). Next, the thick film silver paste is screen-printed and dried on the surface of the 96 alumina substrate 1, the thick film silver paste is screen-printed and dried on the back surface of the 96 alumina substrate 1, and 850 by a belt-type continuous firing furnace. 6 minutes, peak temperature, IN-OU at temperature of ℃
The upper surface electrode layer 2 and the back surface electrode layer 3 are simultaneously formed by firing according to a profile of T time 45 minutes. Next, a lead borosilicate glass paste (white) is screen-printed and dried so as to overlap a part of the back electrode layer 3, and the belt type continuous firing furnace is used (the top electrode layer 2 is brought into contact with the conveyor belt). At a temperature of 850 ° C., a peak time of 6 minutes, I
Fired according to the firing profile of N-OUT 50 minutes,
The second glass layer 6 is formed. Next, a thick film resistance paste containing RuO ₂ as a main component is screen-printed and dried so as to overlap a part of the upper surface electrode layer 2, and the temperature is set to 850 ° C. by a belt-type continuous firing furnace (so as to be floated from a conveyor belt).
The resistance layer 4 is formed by baking at a temperature of 6 minutes and a profile of IN-OUT time of 45 minutes. Next, in order to make the resistance value of the resistance layer 4 between the upper electrode layers 2 uniform, a part of the resistance layer 4 is destroyed by laser light and the resistance value is corrected (L cut, 100 mm / sec, 12 kHz).
z, 5W). Subsequently, a lead borosilicate glass paste (black) is screen-printed and dried so as to completely cover the resistance layer 4, and a belt-type continuous firing furnace (the second glass layer 6 is brought into contact with the conveyor belt). By 590
The first glass layer 5 is formed by firing at a temperature of ℃, according to a firing profile of peak time 6 minutes, IN-OUT 50 minutes. Next, as a preparation step for forming the end face electrodes, the alumina substrate 1 is divided into strips (the pitch side of 1.5 mm is divided) to expose the end face electrodes, and strip-shaped alumina substrates are obtained. On the side surface of the strip-shaped alumina substrate,
A thick film silver paste is applied by a roller so as to overlap a part of the upper surface electrode layer 2 and the rear surface electrode layer 3, and 600 by a belt type continuous firing furnace (so that the second glass layer 6 is in contact with a conveyor belt). The end face electrode layer 7 is formed by firing at a temperature of ℃ for a peak time of 6 minutes and IN-OUT 45 minutes (at this time, when the strip-shaped alumina substrate is viewed from the end face electrode side, it is expressed as shown in FIG. 3). , The paste permeates into the dividing grooves when the silver paste is applied (FIG. 4), so that the first side electrode layer 10 and the second side electrode layer 11 are formed simultaneously with the end face electrode layer 7.). Next, as a preparatory step for electrode plating, the strip-shaped alumina substrate on which the end face electrode layer 7 has been formed is divided into individual pieces (0.8 mm
The pitch side was divided) to obtain individual alumina substrates. And finally, in order to prevent electrode erosion during soldering of the exposed upper surface electrode layer 2, the rear surface electrode layer 3, and the end surface electrode layer 7 and to secure reliability of soldering, the Ni plating layer 8 is formed by electrolytic plating. And Sn—Pb plating layer 9 are formed.

Through the above steps, a square chip resistor according to the present embodiment was prototyped (the finished product has a length of 1.6 mm).
mm, width 0.8 mm, thickness 0.74 mm, and the dimension in the thickness direction was 92.5% of the dimension in the width direction).

According to the present embodiment, since it is not necessary to float the manufactured product from the conveyor belt of the baking furnace during the glass baking and the end face electrode baking, the process is simplified (especially before the end face electrode baking). Therefore, it is not necessary to set a strip-shaped manufactured product.)

Further, the rectangular chip resistor of this embodiment, even when mounted on the side surface of the substrate as shown in FIG. 5, is similar to the rectangular chip resistor mounted by the conventional collective mounting machine of the cylindrical chip resistors. Since the electrode layer is formed on the side surface,
The adhesion strength (the limit load from the direction parallel to the printed board of the rectangular chip resistor) was almost the same as when it was mounted on the main surface of the board (in this case, about 8 kg for side mounting and about 10 kg for surface mounting). Yes, the side mounting of the conventional example was about 3 kg.)

In this embodiment, the glass having a softening point of 560 ± 5 ° C. is used for the first glass layer and the softening point is 6 for the second glass layer.
80 ± 5 ℃ glass was used, but the softening point was 520
Needless to say, similar effects are exhibited if the glass has a temperature of from ℃ to 580 ℃, 630 ℃ to 850 ℃ (however,
Since the softening point of this example is the most stable for the glass composition, the rectangular chip resistor has the best resistance performance. ). The firing temperature of each glass layer is 550.
It may be appropriately selected in the range of ℃ to 620 ℃, 700 ℃ to 950 ℃. The firing temperature of the end face electrode layer 7 is selected in the range lower than the softening point of the second glass layer 6.

[0020]

As is apparent from the above description, according to the rectangular chip resistor of the present invention, since the electrode layer is formed on the side surface, it is sufficient even if the rectangular chip resistor is mounted on the side surface. It has an excellent effect of obtaining a fixing strength.
Further, in the manufacturing method of the present invention, since the side surface electrodes are formed at the same time as the end surface electrodes, there is an effect that the manufacturing can be performed without deteriorating the man-hours at all.

In the rectangular chip resistor of the present invention, first, the second glass layer having a softening point of 630 ° C to 850 ° C is formed at 700 ° C to
Firing at a temperature of 950 ° C., and then firing the first glass layer at a temperature of 550 ° C. to 620 ° C. below the softening point of the second glass layer so that the second glass layer is in contact with the conveyor belt. Further, after the first glass layer is fired, the end face electrode layer is fired at a temperature of 550 ° C. to 660 ° C., which is lower than the softening point of the second glass layer. It is not necessary to float the firing belt from the conveyor belt of the firing furnace, and the firing process is simplified, so that the manufacturing process of the rectangular chip resistor is simplified.

[Brief description of drawings]

1A and 1B are a perspective view and a sectional view, respectively, showing the structure of a rectangular chip resistor according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a method for manufacturing a rectangular chip resistor according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a strip-shaped alumina substrate in the process of manufacturing a rectangular chip resistor according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a coated state of an end face electrode layer and a side face electrode layer in the same example.

FIG. 5 is a sectional view showing the structure of a conventional rectangular chip resistor.

FIG. 6 is an explanatory view showing a state in which a conventional rectangular chip resistor is mounted on a side surface.

FIG. 7 is an explanatory diagram of a conventional glass firing jig for a rectangular chip resistor.

FIG. 8 is an explanatory view of a jig for firing an end face electrode of a conventional rectangular chip resistor.

FIG. 9 is an explanatory view showing an example of a conventional method for manufacturing a rectangular chip resistor.

[Explanation of symbols]

 1 96 Alumina Substrate 2 Top Electrode Layer 3 Back Electrode Layer 4 Resistance Layer 5 First Glass Layer 6 Second Glass Layer 7 End Face Electrode Layer 8 Ni Plating Layer 9 Sn-Pb Plating Layer 10 First Side Electrode Layer 11 Second Side Electrode layer

Claims (2)

[Claims] 1. The length in the thickness direction is 80% to the length in the width direction.
A rectangular plate-shaped insulating sintered substrate having a length of 120%, a pair of upper surface electrode layers formed on one main surface of the sintered substrate, and a part of the pair of upper surface electrode layers. Overlapping resistive layers,
A first glass layer that completely covers the resistance layer, a pair of back surface electrode layers on the other main surface of the sintered substrate, a second glass layer that partially overlaps the back surface electrode layer, and the pair of upper surfaces. A pair of end surface electrode layers electrically connecting the electrode layer and the pair of back surface electrode layers, and two pairs of first side surface electrodes electrically connecting the top surface electrode layer and the end surface electrode layer on two side surfaces. Layers and
A rectangular chip resistor, which is also composed of two pairs of second side surface electrode layers that electrically connect the back surface electrode layer and the end surface electrode layer on two side surfaces. 2. The second glass layer is formed by firing at a temperature of 700 ° C. to 950 ° C., and the first glass layer is fired at a temperature of 550 ° C. to 620 ° C. after the firing of the second glass layer. And baking the pair of end surface electrode layers, the pair of first side surface electrode layers and the pair of second side surface electrode layers at a temperature of 550 ° C. to 660 ° C. after baking the first glass layer. The method for manufacturing a rectangular chip resistor according to claim 1, wherein.