JPH11224809A - Manufacture of square plate type chip resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method, by which a square plate-type chip resistor which is capable of realize high-accuracy mounting by reducing the surface ruggedness of a glass layer can be manufactured. SOLUTION: In a method for manufacturing square plate type chip resistor, a first glass layer 6 and a marked glass layer 7 are formed by baking simultaneously at least first glass paste and marking glass paste in a process for forming a pair of upper-surface electrode layers 2 on an insulating substrate 1, a process for printing and drying the first glass paste on a resistor layer 4 which is formed to overlap part of the electrode layer 2, a process for printing and drying the marking glass paste on the first glass paste, and a process for printing and drying second glass paste on the first glass paste, so that the second glass paste may completely cover the marking glass paste as necessary.

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 square chip resistor mainly mounted on a high-density wiring circuit by an automatic mounting machine.

[0002]

2. Description of the Related Art In recent years, as the demand for lighter, thinner and smaller electronic devices has been increasing, very small square-plate type chip resistors are often used as resistance elements in order to increase the wiring density of circuit boards. It has come to be.

[0003] Further, in order to mount this square plate type chip resistor on a printed circuit board at a high speed, it is almost always mounted by an automatic mounting machine. For this reason, there is an increasing demand for improving the mounting quality of the square plate type chip resistor.

FIG. 3 shows the structure of a conventional square plate type chip resistor. The conventional square plate type chip resistor includes an insulating substrate 11 made of a 96-alumina substrate, an upper electrode layer 12 and an end electrode layer 13 made of a silver-based thick film electrode, a resistance layer 14 made of a ruthenium-based thick film resistor, and a resistance layer 14. Precoat glass layer 15 to cover
And a first glass layer 16, a stamped glass layer 17 and a second glass layer 18. In order to improve the solderability of the exposed electrode surface, the Ni plating layer 19 and the Sn-
The Pb plating layer 20 is applied by electrolytic plating.

[0005]

However, in the conventional square plate type chip resistor, since the upper electrode layer 12 and a part of the resistor layer 14 are formed to overlap each other, a bulge occurs in the overlapping portion, and This swell is the resistance layer 14
Through a pre-coated glass layer 15, a first glass layer 16, and a stamped glass layer 17 which are sequentially formed
It affects the surface of the glass layer 18, that is,
The edge of the surface of the second glass layer 18 starts rising from the overlap of the upper electrode layer 12 and the resistance layer 14 and rises sequentially. As a result, irregularities of about 10 to 20 μ occur on the surface of the second glass layer 18. It was a mess.

When mounting a rectangular chip resistor having an uneven surface on a printed circuit board or the like with an automatic mounting machine as described above, when the suction chip of the automatic mounting machine sucks up the square chip resistor. In many cases, the surface of the second glass layer 18 has irregularities such that the suction pin and the square plate type chip resistor are in point contact with each other due to irregularities on the surface of the second glass layer 18 and the square plate type chip resistor rotates. There is a problem that mounting may be performed diagonally as shown in FIG. In FIG. 4, reference numeral 21 denotes a printed circuit board, 2
2 is a conductor foil, and 23 is a square chip resistor.

An object of the present invention is to provide a method of manufacturing a square plate type chip resistor capable of realizing high-precision mounting by reducing irregularities on the surface of a glass layer. It is.

[0008]

In order to achieve the above object, a method of manufacturing a square plate type chip resistor according to the present invention comprises the steps of forming a pair of upper electrode layers on an insulating substrate; Forming a resistance layer so as to overlap a part of the electrode layer; correcting the resistance value of the resistance layer; printing and drying a first glass paste on the resistance layer; A step of printing and drying a stamping glass paste on the paste, and a step of printing and drying a second glass paste on the first glass paste so as to completely cover the stamping glass paste, if necessary; and at least the first glass paste Forming a first glass layer and a stamping glass layer by simultaneously firing the stamping glass paste and forming a pair of end face electrode layers so as to partially overlap the pair of top electrode layers. But, according to this manufacturing method, in which by reducing the unevenness of the surface of the glass layer can realize high-precision mounting.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a step of forming a pair of upper electrode layers on an insulating substrate;
A step of forming a resistance layer so as to partially overlap the pair of upper electrode layers, and a step of correcting the resistance value of the resistance layer;
A step of printing and drying a first glass paste on the resistance layer, a step of printing and drying a stamped glass paste on the first glass paste, and if necessary, a step of completely printing the stamped glass paste on the first glass paste. Second to cover
Printing and drying a glass paste, simultaneously firing at least the first glass paste and the stamped glass paste to form a first glass layer and a stamped glass layer, and overlapping a part of the pair of upper electrode layers. Forming a pair of end surface electrode layers as described above. According to this manufacturing method, the first glass paste is printed on the resistance layer formed so as to partially overlap the pair of upper surface electrode layers. A step of drying, a step of printing and drying a stamping glass paste on the first glass paste, and a step of, if necessary, completely covering the stamping glass paste on the first glass paste.
In the step of printing and drying the glass paste, at least the first glass paste and the stamped glass paste are simultaneously fired to form the first glass layer and the stamped glass layer. The irregularities on the surface of the glass layer are very small compared to the case where the layer is baked alone, which makes it difficult to mount this square plate type chip resistor on a printed circuit board etc. with an automatic mounting machine. Has an effect that high-precision mounting becomes possible because the square-plate type chip resistor can be reliably sucked up by the suction pin of the automatic mounting machine.

According to a second aspect of the present invention, a step of forming a pair of upper electrode layers on an insulating substrate; a step of forming a resistive layer so as to partially overlap the pair of upper electrode layers; Printing and baking a pre-coated glass layer on the layer, forming a resistance value from above the pre-coated glass layer, and printing a first glass paste so as to cover the resistance layer and the pre-coated glass layer. A drying step;
A step of printing and drying a stamping glass paste on the first glass paste, and a step of printing and drying a second glass paste so as to completely cover the stamping glass paste on the first glass paste as needed; First
A step of forming a first glass layer and a stamping glass layer by simultaneously firing a glass paste and a stamping glass paste; and a step of forming a pair of end face electrode layers so as to partially overlap the pair of upper electrode layers. According to this manufacturing method, the resistive layer formed so as to overlap a part of the pair of upper electrode layers, and the precoated glass layer formed by printing and firing on the resistive layer are covered. Printing and drying the first glass paste, printing and drying the stamping glass paste on the first glass paste, and if necessary, completely covering the stamping glass paste on the first glass paste. 2) printing and drying the glass paste, wherein at least the first glass paste and the stamped glass paste are simultaneously fired to form the first glass layer and the stamped glass layer. Because you are, compared with those by firing seal glass layer and the first glass layer alone, the unevenness of the surface of the glass layer becomes very small, thereby,
When mounting this square plate type chip resistor on a printed circuit board or the like with an automatic mounting machine, the suction pin of the automatic mounting machine can reliably suck up the square plate type chip resistor, enabling high-precision mounting. It has the effect of becoming.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 are cross-sectional views of a square chip resistor obtained by a method of manufacturing a square chip resistor according to an embodiment of the present invention.

First, as shown in FIG. 1, a rectangular chip resistor according to an embodiment of the present invention comprises an insulating substrate 1 made of a 96-alumina substrate and a pair of upper electrode layers 2 made of a silver-based thick film electrode. And a pair of end surface electrode layers 3, a resistance layer 4 made of a ruthenium-based thick film resistor provided so as to overlap a part of the pair of upper surface electrode layers 2, and a pair of recesses on the resistance layer 4, A pre-coated glass layer 5 having a length equal to or less than the interval between the upper electrode layers and having a height substantially equal to the height of the swelling of the overlapping portion of the upper electrode layer 2 and the resistance layer 4; A first glass layer 6 provided so as to completely cover the layer 4;
A stamping glass layer 7 provided on a glass layer 6;
A second glass layer 8 provided on the glass layer 6 so as to completely cover the sealing glass layer 7. In order to improve the solderability on the exposed electrode surface, N
The i plating layer 9 and the Sn—Pb plating layer 10 are formed by electrolytic plating.

Next, a method of manufacturing the square plate type chip resistor according to the embodiment of the present invention shown in FIG. 1 will be described. First, an insulating substrate 1 made of a 96-alumina substrate having excellent heat resistance and insulating properties is received. In order to divide the insulating substrate 1 into strips and individual pieces, grooves (die molding at the time of a green sheet) for division are formed.
Next, a thick-film silver paste is screen-printed on the insulating substrate 1 and baked in a belt-type continuous firing furnace at a temperature of 850 ° C. with a profile of a peak time of 6 minutes and an IN-OUT time of 45 minutes. The electrode layer 2 is formed. Next, a thick film resistor paste containing RuO ₂ as a main component is screen-printed so as to partially overlap the pair of upper electrode layers 2, and a belt-type continuous firing furnace is used at a temperature of 850 ° C. for a peak time of 6 minutes. The resistance layer 4 is formed by firing with a profile of IN-OUT time of 45 minutes. Next, a pre-coated glass paste is printed on the resistance layer 4 using a pattern having a length equal to or less than the electrode interval between the pair of upper electrode layers 2, and a peak time is set at 590 ° C. by a belt-type continuous firing furnace. Baking is performed according to a baking profile of 6 minutes and IN-OUT time of 50 minutes to form a precoated glass layer 5. Next, in order to make the resistance value of the resistance layer 4 between the pair of upper electrode layers 2 uniform, the resistance layer 4 and a part of the pre-coated glass layer 5 are broken by a laser beam to correct the resistance value. Further, a first glass paste is screen-printed so as to completely cover the resistance layer 4 and the pre-coated glass layer 5, and dried at 150 ° C. for 10 minutes in a near-infrared drying oven. Further, a stamping glass paste is screen-printed on the dried first glass paste, and dried at 110 ° C. for 10 minutes in a near-infrared drying oven. Further, the second glass paste is screen-printed on the dried first glass paste so as to completely cover the dried stamped glass paste, and is dried by a near-infrared drying oven.
Dry at ℃ for 10 minutes. Then, at a temperature of 590 ° C. in a belt type continuous firing furnace, a peak time of 6 minutes, and IN-OUT
The first glass layer 6, the stamped glass layer 7, and the second glass layer 8 are formed at the same time by firing with a firing profile of 50 minutes. Next, as a preparatory step for forming the end face electrode layer, the insulating substrate 1 is divided into strips as a primary substrate division to expose the end face electrode layer, thereby obtaining a strip-shaped insulating substrate. Then, a thick-film silver paste is applied to the side surface of the strip-shaped insulating substrate by a roller so as to overlap a part of the pair of upper electrode layers 2, and is applied by a belt-type continuous firing furnace.
At a temperature of 0 ° C., a peak time of 6 minutes and an IN-OUT time of 45 minutes
And a pair of end face electrode layers 3 are formed. Next, as a preparation step of the electrode plating step, the strip-shaped insulating substrate on which the end surface electrode layer 3 has been formed is divided into individual substrates, thereby obtaining individual insulating substrates. Finally, a pair of exposed upper electrode layers 2
The Ni plating layer 9 and the Sn—Pb plating layer 10 are formed by electrolytic plating in order to prevent electrode erosion during soldering of the pair of end face electrode layers 3 and secure reliability of soldering.

Through the above steps, a square chip resistor according to an embodiment of the present invention was manufactured.

The second glass layer 8 of this square plate type chip resistor
The surface irregularities became 5 μm or less, and the surface of the glass layer became flat. As a result, the mountability is extremely excellent, and the oblique mounting (FIG. 4) that occurred in the conventional product is 6 out of 10,000.
From 1 to 0 out of 10,000.

Further, other characteristics (resistance variation, T
(CR, life characteristics) were also confirmed to be equivalent to the conventional product.

In the embodiment of the present invention, the pre-coated glass layer 5 is formed in order to reduce the variation in the resistance value. However, as shown in FIG. The first glass layer 6 is formed in the upper concave portion so as to have a length equal to or less than the distance between the pair of upper electrode layers 2 and as high as the bulge of the overlapping portion between the part of the upper electrode layer 2 and the resistance layer 4. By doing so, the flatness of the surface of the glass layer can be ensured.

[0018]

As described above, according to the method of manufacturing a square plate type chip resistor of the present invention, a step of forming a pair of upper electrode layers on an insulating substrate, and a step of partially overlapping the pair of upper electrode layers. Forming a resistive layer on the resistive layer, correcting the resistance value of the resistive layer, printing and drying a first glass paste on the resistive layer, and printing a stamped glass paste on the first glass paste. A step of drying and, if necessary, a step of printing and drying a second glass paste so as to completely cover the stamping glass paste on the first glass paste;
A step of simultaneously firing at least the first glass paste and a stamping glass paste to form a first glass layer and a stamping glass layer, and forming a pair of end face electrode layers so as to partially overlap the pair of top electrode layers. According to this manufacturing method, a step of printing and drying a first glass paste on a resistance layer formed so as to overlap a part of the pair of upper electrode layers; A step of printing and drying a stamping glass paste on the paste and, if necessary, a step of printing and drying a second glass paste on the first glass paste so as to completely cover the stamping glass paste. Since the first glass layer and the stamped glass layer are formed by simultaneously firing the paste and the stamped glass paste, the first glass layer and the stamped glass layer are fired independently. The irregularities on the surface of the glass layer are very small compared to those that are used, so that when mounting this square chip type resistor on a printed circuit board etc. with an automatic mounting machine, the suction of the automatic mounting machine Since the square plate type chip resistor can be reliably sucked up by the pin, it has an excellent effect that high precision mounting becomes possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a square chip resistor obtained by a method of manufacturing a square chip resistor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a square chip resistor obtained by a method of manufacturing a square chip resistor according to another embodiment of the present invention.

FIG. 3 is a sectional view showing an example of the structure of a conventional square plate type chip resistor.

FIG. 4 is an explanatory view showing a state in which a conventional square plate type chip resistor is mounted obliquely.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Insulating substrate 2 Upper electrode layer 3 End electrode layer 4 Resistive layer 5 Pre-coated glass layer 6 First glass layer 7 Stamped glass layer 8 Second glass layer 9 Ni plating layer 10 Sn-Pb plating layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jun Nakamoto 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] A step of forming a pair of upper electrode layers on an insulating substrate; a step of forming a resistive layer so as to partially overlap the pair of upper electrode layers; and correcting the resistance of the resistive layer. And printing a first glass paste on the resistance layer.
A step of drying, a step of printing and drying a stamping glass paste on the first glass paste, and a step of printing and drying a second glass paste on the first glass paste so as to completely cover the stamping glass paste if necessary. Forming a first glass layer and a stamped glass layer by simultaneously firing at least the first glass paste and the stamped glass paste; and forming a pair of end face electrode layers so as to partially overlap the pair of upper electrode layers. Forming a square chip resistor. 2. A step of forming a pair of upper electrode layers on an insulating substrate; a step of forming a resistive layer so as to partially overlap the pair of upper electrode layers; and forming a pre-coated glass layer on the resistive layer. A step of forming by printing and baking, a step of correcting the resistance value from above the precoated glass layer, a step of printing and drying a first glass paste so as to cover the resistance layer and the precoated glass layer, A step of printing and drying a stamping glass paste on the first glass paste, and a step of printing and drying a second glass paste so as to completely cover the stamping glass paste on the first glass paste as necessary. (1) a step of simultaneously firing the glass paste and the stamping glass paste to form a first glass layer and a stamping glass layer; and a pair of ends so as to partially overlap the pair of upper electrode layers. Forming a plane electrode layer.