JPH07147207A - Manufacture of chip resistor - Google Patents

Abstract

PURPOSE:To prevent imperfect contact between a measuring terminal and an upper electrode layer at the time of resistance value correction, by forming a secondary thick film upper electrode layer on a primary thin film upper electrode layer so as not to overlap a resistor. CONSTITUTION:An electrode paste composed of metal organic matter whose main component is Au is screen-printed on both sides of each individual segment type part formed on the surface of an insulating substrate 1, and a primary thin film upper electrode layer 3 is formed by baking. A resistance layer 4 is formed on a part of the primary thin film electrode layer 3 so as to overlap there, and a precoat glass layer 5 is formed so as to completely cover the resistance layer 4. A secondary thick film electrode layer 6 is formed by screen- printing Ag based paste on the primary thin film upper electrode layer 3 and baking it. At the time of resistance correction, a measuring terminal comes into contact with the secondary thick film upper electrode layer 6, so that imperfect contact can be prevented without being affected by surface roughness of the insulating substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a method of manufacturing a chip resistor used in electronic circuits.

[0002]

2. Description of the Related Art In recent years, hybrid ICs are small and lightweight.
As the products have become thinner, new products have been developed aiming at high-density mounting of electronic parts, resource saving, and improvement of reliability. Even in the case of a chip resistor as one of electronic components, there is a widespread demand from consumers for a smaller and more accurate chip resistor than ever before and at a low cost.

An example of a conventional method of manufacturing a chip resistor will be described below with reference to the process chart of FIG.

That is, first, in step a, a heat-resistant insulating substrate 21 made of a high-purity alumina substrate or the like is received. Dividing grooves 22 for dividing the insulating substrate 21 into strips and individual pieces are formed. Next, in step b, the Au-based upper surface electrode layer 23 is formed on both sides of each individual piece on the insulating substrate 21. Then, in step c, the resistor layer 24 is formed so as to partially overlap the upper surface electrode layer 23. Next, in step d, in order to correct the resistance value of the resistor layer 24 to a predetermined value, a resistance value correcting step of forming the trimming groove 25 in the resistor layer 24 by a laser trimming method or the like is executed.

Next, in step e, a glass layer 26 for overcoating is formed on the surface of the resistor layer 24 in order to protect the resistor layer 24 formed in step d. The next step f is the insulating substrate 21.
Is a primary substrate dividing step of dividing the strip-shaped substrate 21a into a strip-shaped substrate 21a. This step is a preparatory step for forming the end face electrode layer 27 on the end face of the strip-shaped substrate 21a in the next step g.

The next step h is a step of dividing the strip-shaped substrate 21a into individual substrates 21b, which is a preparatory step for plating the electrode surface exposed in the next step i. In the step i, the electrode plating layer 28 for ensuring reliability during soldering is formed on the electrode surface, and the chip resistor is formed by the steps a to i.

[0007]

However, since the conventional chip resistor has a temperature coefficient of resistance within ± 50 ppm / ° C., Au-based paste is generally used for the upper electrode layer 23. Since Au is expensive, it leads to an increase in production cost. For this reason, the upper electrode layer 23 has A
If the u-based metal organic paste (resinate paste) is used, the upper surface electrode layer made of a thin film can be formed, and the chip resistor can be manufactured at low cost. However, since the upper surface electrode layer is a thin film, it becomes easy to be affected by the surface roughness of the insulating substrate 21 in the resistance value correcting step of step d,
There has been a problem that a poor contact with the measurement terminal occurs and a defective resistance value frequently occurs.

The present invention solves the above problems and has the same excellent reliability as that when a thick Au paste is used for the upper electrode layer, and also has a poor contact with the measurement terminal in the resistance correction step. It is an object of the present invention to reduce the yield deterioration due to defective resistance and to provide a chip resistor at low cost by eliminating the above.

[0009]

In order to achieve the above object, a method of manufacturing a chip resistor according to the present invention has vertical and horizontal dividing grooves provided on at least one of front and back surfaces so as to face each other. A step of printing an electrode material made of an Au-based metal organic material on the surface of the insulating substrate and baking the electrode material to form a pair of primary thin film upper surface electrode layers, and a step of overlapping the pair of primary thin film upper surface electrode layers. A resistor layer on the first thin film upper electrode layer, and a step of forming a pair of secondary thick film upper electrode layers on the primary thin film upper electrode layer so as not to cover the resistor layer; A step of correcting the resistance value of the layer, a step of forming an overcoat glass layer so as to completely cover the resistor layer, and a step of primarily dividing the insulating substrate to form an end face electrode layer on the insulating substrate. And of this primary divided board The step of forming an electrode layer on the surface portion, the step of subdividing the primary divided substrate into pieces to form the electrode plating layer, and the step of forming a plating layer on the exposed electrode portion after the secondary division And a process.

[0010]

With the above structure, since the metal organic paste is used for the primary thin film upper surface electrode layer, the material cost can be reduced, and at the same time, the secondary thick film is formed on the primary thin film upper surface electrode layer. Since the thick film electrode layer is formed as the upper surface electrode layer so as not to overlap the resistor, the measuring terminal contacts with this secondary thick film upper surface electrode layer in the process of correcting the resistance value, so the thin film upper surface Unlike the case where only the electrode layer is formed, it is not affected by the surface roughness of the substrate, and the resistance value failure due to the contact failure at the time of connecting the measurement terminals can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a process diagram showing an example of a method of manufacturing a chip resistor, and FIG. 2 is a sectional view of a product manufactured by the process. In the figure, A is a receiving step. First, in step A, the insulating substrate 1 made of, for example, alumina 96 having excellent heat resistance and insulating properties is received. This insulating substrate 1
On the front and back surfaces of the insulating substrate 1, vertical and horizontal dividing grooves 2 are provided so as to face each other so that the insulating substrate 1 can be divided into strips and individual pieces by die molding at the time of green sheet or the like. Has been formed.

Next, in step B, an electrode paste made of a metal organic compound containing Au as a main component is screen-printed on both sides of each individual piece formed on the surface of the insulating substrate 1, and the belt type continuous firing furnace is used. The primary thin film upper surface electrode layer 3 is formed by baking at a temperature of 850 ° C. according to a profile (setting conditions) with a peak time of 6 minutes and an IN-OUT (holding) time of 45 minutes.

Next, in step C, a RuO ₂ -based resistance paste is screen-printed so as to overlap a part of the primary thin film upper surface electrode layer 3, and the temperature is set to 850 ° C. in a belt type continuous firing furnace. The resistor layer 4 is formed on each individual part by firing according to a profile with a peak time of 6 minutes and an IN-OUT time of 45 minutes.

Next, in step D, in order to protect the resistor layer 4 formed in step C and to improve the laser trimming property in the subsequent step, the glass for precoating should cover the resistor layer 4 completely. The paste is screen-printed and baked in a belt-type continuous baking furnace at a temperature of 600 ° C. according to a profile with a peak time of 6 minutes and an IN-OUT time of 45 minutes to form a precoated glass layer 5.

Next, in the step E, 55 is formed on the primary thin film upper surface electrode layer 3 in order to eliminate the resistance value failure due to the contact failure at the time of connecting the measuring terminals in the resistance value correcting step of the subsequent step F.
An Ag-based paste having a softening point of 0 to 650 ° C. is screen-printed, and a belt-type continuous firing furnace is used to 600
The secondary thick film upper surface electrode layer 6 is baked at a temperature of ℃ at a peak time of 6 minutes and an IN-OUT time of 45 minutes.
To form. Then, in order to correct the resistance value of the resistor layer 4 to a predetermined value, a resistance value correction step F of forming the trimming groove 7 in the resistor layer 4 by laser light is executed.

Next, in order to protect the resistor layer 4 obtained in the previous step in step G, a glass paste for overcoating is screen-printed so as to completely cover the precoat glass layer 5, and the belt type continuous coating is carried out. The overcoat glass layer 8 is formed by firing in a firing furnace at a temperature of 600 ° C. with a profile having a peak time of 6 minutes and an IN-OUT time of 45 minutes.

The next step H is a substrate primary dividing step in which the insulating substrate 1 is divided into strips to obtain strip-shaped substrates 1a. This step H is a preparatory step for forming the end face electrode layer 9 in the next step I. This is a step of exposing the end face electrodes.

In step I, the thick film Ag is formed on the side surface of the strip-shaped substrate 1a so as to overlap a part of the secondary thick film upper surface electrode layer 6.
The paste is applied by rollers and in a belt-type continuous firing furnace at a temperature of 600 ° C. for a peak time of 6 minutes, I
The end face electrode layer 9 is formed by firing in a profile of N-OUT time 45 minutes.

Next, as a preparatory step for plating the end face electrode layer 9, the strip-shaped substrate 1a on which the end face electrode layer 9 has been formed is divided into individual substrate 1b, which is a step of subdividing the substrate. Run J.

Finally, in order to prevent electrode erosion (disappearance) during soldering of the exposed secondary thick film upper surface electrode layer 6 and end face electrode layer 9 and to secure reliability during soldering, Ni, Sn-Pb plating layer 1 by electrolytic plating
Step K of forming 0 is performed.

By carrying out the above steps A to K, a chip resistor 11 as shown in FIG. 2 was prototyped.

As described above, according to the method of manufacturing a chip resistor of the present invention, the resistance value failure rate due to contact failure at the time of connecting the measuring terminals in the resistance value correcting step is determined by the conventional chip resistance using the metal organic paste for the upper surface electrode layer. It was possible to reduce from 10% of the container to almost 0%.

In the embodiment of the present invention, the step D of printing and firing the precoat glass paste is added to protect the resistor layer 4, but this step D may be omitted.

[0025]

As is apparent from the above description, according to the method of manufacturing the chip resistor of the present invention, the following effects can be obtained. (1) Since the Au-based metal organic paste is fired to form the primary thin film upper surface electrode layer, it is possible to reduce reaction diffusion between the resistive film layer and the thick resistive film.
It is possible to inexpensively provide a chip resistor having characteristics equivalent to those of a conventional chip resistor using the system paste for the upper surface electrode layer. (2) If the entire surface of the primary thin film upper surface electrode layer surrounded by the pre-coated glass layer and the end surface electrode layer is covered with the secondary thick film upper surface electrode layer of the thick film Ag paste, the measurement terminals will become Since the second thick film upper surface electrode layer is brought into contact with the second thick film upper surface electrode layer, the resistance value is not affected by the surface roughness of the insulating substrate and the resistance value failure due to the contact failure at the time of connecting the measurement terminals can be eliminated. In addition, a case where a conductive resin paste is used to form the second thick film upper surface electrode layer may be considered, but a thick film glaze paste is used at a high temperature (600
The surface electrode strength can be increased by forming the upper electrode.

[Brief description of drawings]

FIG. 1 is a process diagram showing a method of manufacturing a chip resistor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a chip resistor obtained by the same manufacturing method.

FIG. 3 is a process diagram showing a conventional method for manufacturing a chip resistor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 1b Piece-shaped substrate (piece) 2 Dividing groove 3 Primary thin film upper surface electrode layer 4 Resistor layer 6 Secondary thick film upper surface electrode layer 8 Overcoat glass layer 9 End surface electrode layer 10 Plating layer 11 Chip Resistor

Front page continuation (72) Inventor Akio Fukuoka, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. An electrode material made of an Au-based metal organic material is printed and baked on the surface of an insulating substrate having vertical and horizontal dividing grooves provided on at least one of the front and back surfaces so as to face each other. A step of forming a pair of primary thin film upper surface electrode layers, a step of forming a resistor layer so as to overlap with the pair of primary thin film upper surface electrode layers, and so as not to hang over the resistor layer, and Forming a pair of secondary thick film upper surface electrode layers on the primary thin film upper surface electrode layer, modifying the resistance value of the resistor layer, and overcoating so as to completely cover the resistor layer. A step of forming a glass layer, a step of primary dividing the insulating substrate to form an end surface electrode layer on the insulating substrate, a step of forming an electrode layer on an end surface portion of the primary divided substrate, and an electrode In order to form the plating layer 2. A method of manufacturing a chip resistor, comprising: a step of secondarily dividing the divided substrate into individual pieces; and a step of forming a plating layer on an electrode portion exposed after the second division. 2. The secondary thick film upper surface electrode layer comprises 550 to 65.
2. The method for manufacturing a chip resistor according to claim 1, wherein the thick film glaze paste of Ag type having a softening point of 0 [deg.] C. is formed by printing and firing.