JPH01289222A - Manufacture of chip resistor - Google Patents

Abstract

PURPOSE:To obtain a chip resistance without causing a dislocation of a conductor, a resistor and the like due to contraction of a substrate by a method wherein the conductor, the resistor and the like as well as grooves for division are formed on an unfired sheet for substrate formation and they are fired simultaneously. CONSTITUTION:A conductor paste 2 and a resistor paste 3 which have been manufactured in advance are printed and formed, in prescribed patterns, on a sheet 1 for substrate formation use by using a screen printing method. Then, grooves 4 for division to divide individual resistances 5 are formed in the sheet 1 for substrate formation use, and the sheet 1 for substrate formation use, the conductor paste 2, the resistor paste 3 and the like are fired simultaneously in the air. By this firing operation, the sheet 1 for substrate formation use, the conductor paste 2, the resistor paste 3 and the like are constricted collectively. In addition, their coefficients of contraction are equal. By this setup, a problem of a dislocation between a conductor 20 and a resistor 30 or their positional deviation with reference to a substrate 10 is not caused. Accordingly, it is possible to obtain a resistance whose accuracy and reliability are high.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a chip resistor, which simultaneously manufactures a plurality of chip resistors by co-firing with a substrate material.

<Prior Art> Conventionally, a method for simultaneously manufacturing a plurality of chip resistors has been carried out through the following steps.

■ Producing raw sheets for alumina ceramic substrates,
A dividing groove is formed in this.

(2) The raw sheet is fired at about 1600°C to obtain an alumina ceramic substrate.

■Print a predetermined pattern of conductive paste on the above board,
A resistor paste is printed and fired to bond to the conductor, an overcoat glass is printed and fired over the resistor and the conductor, and each resistor is trimmed.

Alternatively, after printing and baking a low antibody, trimming is performed, and then a glass for overcoat is printed and baked.

■ Divide the board using the above dividing groove to obtain each chip resistor. - However, this manufacturing method has the following drawbacks due to shrinkage during firing of the raw sheet for the alumina ceramic substrate.

Conductors and resistors are mainly formed by printing their paste onto a fired alumina substrate using a screen printing method using a printing plate of a predetermined standard, but this method does not take into account shrinkage of the substrate. When printing, the formation positions of the conductor and resistor may be misaligned, resulting in a poor connection between them.Also, if the conductor or resistor is not formed in the correct position with respect to the board, the conductor or resistor may be placed inside the dividing groove. In some cases, cracks may occur in conductors, resistors, etc.

In particular, since the substrate and printing plate are aligned by aligning their negative sides, misalignment accumulates near the opposite end, and the above-mentioned drawbacks become noticeable in chip resistors in that area. . Therefore, the larger the board size, the
Alternatively, the smaller the size of the chip resistor, the higher the incidence of defective products.

Therefore, conductors, resistors, etc. are formed using a printing plate that matches the dimensions of the shrunken board, but the shrinkage rate of the board varies depending on the composition of the board, firing conditions, etc., and the dimensions of the board are not constant. , -fl The printed version of the neck cannot be used. Therefore, the dimensions of the substrates are divided into classes based on a predetermined size range from the upper limit to the lower limit based on actual measurements, and printing plates (50 to several hundred types) for each class are prepared in advance, and the dimensions of each fired substrate are The printing plates are measured each time, and the appropriate one is selected from among the many types of printing plates mentioned above.

However, this method has the disadvantage that many types of printing plates must be prepared. In particular, the smaller the size of the chip resistor, the more detailed the classification and the greater the number of printing plates. For example, 0,8ma
In the case of the production of +x 1 , 6II1m chip resistors, the number of printing plates extends to more than IOO species.

In addition, considering productivity, the dimensions of the substrate (before firing) are usually about 50 mm x 50 mm, but in order to minimize the dimensional error between the substrate and printing plates and not increase the number of printing plates. Therefore, larger dimensions cannot be used.

Furthermore, with the above method, it takes time to measure the dimensions of the substrate and select the printing plate to be used, and it is not possible to perfectly match the dimensions of the substrate and printing plate, so it is difficult to obtain a sufficient improvement in yield. It's not perfect.

In addition, as a method of not forming dividing grooves on the substrate in advance, it is possible to form conductors, resistors, etc. on the substrate and then form dividing grooves by laser processing or cutting them directly. With this method, the reliability of division is low because the cost is high and it is difficult to process grooves with high precision, especially for small-sized chip resistors.

<Problems to be Solved by the Invention> The purpose of the present invention is to provide a method for manufacturing a chip resistor that eliminates the above-mentioned drawbacks of the prior art and that allows easy manufacturing of highly accurate and reliable chip resistors. It is about providing.

In recent years, substrate materials that can be fired at low temperatures have been developed, making it possible to simultaneously bake substrate materials, conductors, resistors, etc. at low temperatures of approximately 1000°C or less. became. Therefore, the present inventors applied this technology to form conductors, resistors, etc. and dividing grooves on an unfired substrate forming sheet, instead of forming conductors, resistors, etc. on an alumina substrate after firing. It has been discovered that by forming and simultaneously firing these, a chip resistor can be manufactured without causing the problem of misalignment of conductors, resistors, etc. due to shrinkage of the substrate, and has arrived at the present invention.

That is, the present invention provides a method for manufacturing a chip resistor that simultaneously manufactures a plurality of chip resistors, in which at least a conductor paste and a resistor paste are provided on an unfired substrate forming sheet, and dividing grooves are formed in the sheet. form,
The present invention provides a method for manufacturing a chip resistor, which is characterized in that these are fired simultaneously and then divided into individual chip resistors.

Further, it is preferable that the conductor paste and the resistor paste be formed by a screen printing method.

The simultaneous firing is preferably performed at a temperature of 1000° C. or lower.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for manufacturing a chip resistor according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

1 to 5 are perspective views showing process examples of the method for manufacturing a chip resistor of the present invention, respectively.

1) First, a substrate forming sheet 1 as shown in FIG. 1 is produced.

That is, the following constituent materials of the substrate are mixed, a vehicle such as a binder and a solvent is added thereto, and these are kneaded to form a paste (slurry). ~1.0
The sheet is made into a sheet with a thickness of about mm.

The constituent materials of the substrate include materials that can be fired simultaneously with conductor paste, resistor paste, etc., such as alumina-borosilicate glass, alumina-lead borosilicate glass, alumina-barium borosilicate glass, and alumina-borosilicate glass.
Low temperature sintered materials containing glass and oxide aggregates such as calcium borosilicate glass, alumina-strontium borosilicate glass, etc. are preferred.

In such a substrate material, the glass content is generally preferably about 50 to 70 wt%.

Vehicles include binders such as ethyl cellulose, polyvinyl butyral, methacrylic resins, acrylic resins such as butyl methacrylate, solvents such as terpineol, butyl carpitol, butyl carpitol acetate, acetate, toluene, alcohol, xylene, and other various dispersants. , activators, etc., and any one of these may be added as appropriate depending on the purpose.

Suitable examples of the substrate material include those described in Japanese Patent Application No. 62-215242 disclosed by the applicant of the present invention.

2) Next, as shown in FIG.
The conductor paste 2 and resistor paste 3 previously produced above are printed and formed into a predetermined pattern, preferably by screen printing. Furthermore, if necessary, an overcoat layer (indicated by diagonal lines in FIG. 5) may be provided on the conductor paste 2 and the resistor paste 3 to cover the conductor paste 2 and the external conductor, leaving only the joints. good. This overcoat layer may be formed after trimming, which will be described later.

Since the printing and forming of the conductor paste 2 and the resistor paste 3 are performed on unfired substrate forming sheets with constant dimensions, only one type of printing plate is required for one chip size, which is different from the conventional There is no need to select and use one with appropriate dimensions from among a wide variety of types.

Note that the conductor paste 2 and the resistor paste 3 may be formed in any order. Normally, after forming the conductor paste 2, the resistor paste 3 is formed to connect to it, but for example, when the size of the chip resistor to be manufactured is small, after forming the resistor paste 3, In some cases, the conductive paste 2 is formed so as to be connected to.

After printing and forming the conductor paste 2 and the resistor paste 3, their surfaces are smoothed (glazed) as required. Note that this step may be performed after firing and trimming.

Such a conductor paste 2 is produced by mixing metal particles, which are the basic composition of the conductor, and glass frit, adding a vehicle such as a binder and a solvent as described above, and kneading these to form a slurry. can get.

Examples of metal particles include Ag or Ag-based alloys, Au
Or Au-based alloy, Pd, Ni.

Examples include Cu, and one or more of these can be added.

Examples of Ag-based alloys include Ag-Pd alloys containing preferably 30 wt% or less of Pd, preferably 20 wt%, as binary or higher alloys of Ag and a desired metal.
Ag-Pd- containing the following Pd and 10 wt% or less pt
Pt alloy, preferably Ag containing 15 wt% or less of pt
-pt gold alloy.

A conductor mainly composed of an Ag-Pd alloy is preferable as the outer conductor because it has excellent migration resistance and moisture resistance.

Note that the content of the metal particles is preferably about 80 to 95 wt%.

Moreover, it is preferable that the average particle diameter of the metal particles is about 0.1 to 5 μm.

The resistor paste 3 is made by mixing conductive phase particles, which are the basic composition of the resistor, and glass frit, adding the same binder, solvent, and other vehicles as described above, and kneading these to form a slurry. can get.

As the conductive phase particles, for example, amorphous or crystalline R
ub, B i 2 R called pyrocool compound
u2o, ,P b2 Ruz Oe,s,CdB1R
u2O,, NdB1Ru207, B i I nRu,
O,, B i2 I rRuo,, GdB i Ru2
07% BaRuOs, Ba2 Rub4
．． 5rRuO3, CaRu03, Co2 Rub4, LaRu0
．． , ruthenium compounds such as Li Rubs, SnO2,
Examples include LaB, and the like.

The content of conductive phase particles in the resistor paste is 10 to 70
About wt% is preferable.

Further, the average particle diameter of the conductive phase particles is preferably about 0.05 to 1 μm.

As the glass frit contained in the conductor paste 2 and the resistor paste 3, for example, commonly used glass frits such as borosilicate glass, lead borosilicate glass, barium borosilicate glass, calcium borosilicate glass, strontium borosilicate glass, zinc borosilicate glass, etc. Examples include those used as Nigarasu frit.

Moreover, it is preferable that the average particle diameter of the glass frit is about 0.5 to 5 μm.

Examples of the overcoat layer include glasses such as the above glasses and mixtures thereof.

Although the size of the substrate forming sheet 1 is usually about 50 mm x 50 mm, the dimensions of the substrate forming sheet 1 are not limited to this in the present invention. In particular, since there is no displacement of the resistor and conductor due to shrinkage of the substrate as in the conventional case, it is possible to use a resistor with dimensions larger than the above, and it is possible to manufacture more chip resistors in one firing. It has the advantage of being able to

In addition, the number of chip resistors formed on one substrate forming sheet is, for example, when the sheet size is 50 mm x 50 mm.
In this case, about 300 to 1200 pieces are possible.

3) Next, as shown in FIG.
A dividing groove 4 for dividing into each chip resistor 5 is formed.

This dividing groove 4 is formed in a straight line corresponding to the row and column of each chip resistor as shown in the figure, and preferably can divide all the chip resistors into equal sizes. Moreover, the dividing groove 4 may be a broken line or the like.

The cross-sectional shape of the dividing groove 4 is preferably a 7-shaped one, and the depth of the groove 4 is such that it can easily and accurately divide the substrate after firing. 1/3~
It is best to set it to about 1/4.

Formation of such dividing grooves 4 can be performed using a dedicated grooving machine or a mold using a sharp blade.

Note that the dividing grooves 4 may be formed before printing and forming the conductor paste 2, resistor paste 3, and the like.

4) Next, as shown in FIG.
, conductor paste 2, resistor paste 3, etc. are fired simultaneously under the following conditions.

The firing temperature is 1000°C or less, preferably 850-9
The temperature is preferably about 50°C and the firing time is preferably about 120 to 180 minutes.

Examples of the firing atmosphere include air and inert gases such as 02, N2, etc. Among them, air is preferable because it is simple and low cost.

The substrate forming sheet 1, the conductor paste 2, the resistor paste 3, etc. shrink during firing, but they shrink as a unit, and their shrinkage rates are almost the same, so the conductor 20
There is no problem of misalignment between the resistor 30 and the resistor 30 or misalignment of these with respect to the substrate 10.

The thickness of the conductor 20 and the resistor 30 formed by firing is not particularly limited, but for example, the former is 5 to 15 μm.
The latter is about 5 to 15 μm. Further, the conduction resistance of the resistor 30 is usually about 10 to 10'Ω/hole.

Note that after the simultaneous firing, the resistor 30 may be
Trimming is performed to adjust the resistance value (see Figure 4). This trimming may be performed by a normal method such as laser processing.

5) Next, as shown in FIG. 5, the substrate 10 is divided by the dividing grooves 4 to form each chip resistor 5.

For each divided chip resistor, roller
External electrodes are formed using a squeegee method, etc., and necessary post-processing such as plating is performed to produce a product.

Note that the chip resistor 5 is, for example, 1.6 mm x 3.2
From the large size of about 0.8mm x 1.6m
It is possible to manufacture various sizes up to a small size of about m.

<Example> A paste obtained by mixing alumina borosilicate glass containing an alkaline earth oxide and alumina and adding a vehicle to this was formed into a sheet for a substrate with a thickness of 0.51,
On top of that, there is a Rub of 1.2mm x 0.6mm+ based on the standard.
After printing and drying the resistor paste mixed with , and glass,
An electrode paste of Ag-Pd alloy was printed over it and dried.

Next, based on the printing standard, after cutting grooves into the substrate sheet, the outer shape was punched out using a mold of 75 mm x 100 mm.
This was baked at 900℃ for 2 hours, and 60III11×8
A substrate of 011I11 was obtained.

After trimming each low antibody to the desired resistance value, overcoat glass was printed and baked at 600°C.

There was no misalignment of the resistor or electrode with respect to the dividing groove, and no misalignment of the overcoat that would cause problems in the next process occurred.

The substrate was divided by dividing grooves, and then terminal electrodes were attached and plating was performed to obtain a chip resistor. Although 3500 0.8 mm x 1.611111 chip resistors were obtained from one substrate, there were no defective products due to misalignment.

<Effects of the Invention> According to the method for manufacturing a chip resistor of the present invention, in addition to the original effects of low-temperature co-firing technology such as enabling firing in air through low-temperature co-firing and simplifying the manufacturing process, the following advantages can be achieved. There is a similar effect.

In the present invention, by forming a conductor paste, a resistor paste, etc. on an unfired substrate forming sheet and firing these at the same time, it is possible to eliminate the variation in the shrinkage rate of alumina substrates as in the conventional method when manufacturing chip resistors. There is no need to take measures to deal with this, and in particular, there is no need to prepare a variety of printing plates of different sizes and to select and use the appropriate one from among them.

In addition, since the mutual positional relationship of the substrate forming sheet, conductor paste, and resistor paste is determined before firing, no misalignment will occur between them regardless of the shrinkage rate of the substrate forming sheet. Therefore, a highly accurate and reliable chip resistor can be manufactured.

In particular, in the conventional method, small-sized chip resistors had a high incidence of defective products, but the present invention has a great advantage in that even small-sized chip resistors can obtain high reliability.

In addition, in the conventional method, the size of the substrate was limited due to accuracy problems (upper limit 5010111X501!1111
However, in the present invention, even if the size of the substrate forming sheet is increased, the accuracy and reliability of the resulting chip resistor will not decrease, so a larger number of chip resistors can be made from a dog-sized substrate forming sheet in one firing. A chip resistor can be obtained, and productivity can therefore be improved.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, FIG. 3, FIG. 4, and FIG. 5 are perspective views each showing a process example of the method for manufacturing a chip resistor of the present invention. Explanation of symbols 1... Board forming sheet, 10... Board, 2... Conductor paste, 20... Conductor, 3... Resistor paste, 30... Resistor, 4... Dividing groove, 5... Chip resistor patent applicant TDC Co., Ltd. FIG, I FIG, 2 FIG, 3] FIG, 5 and

Claims (3)

[Claims] (1) In a method for manufacturing a chip resistor that simultaneously manufactures a plurality of chip resistors, at least a conductor paste and a resistor paste are provided on an unfired substrate forming sheet, and
A method for manufacturing a chip resistor, comprising forming dividing grooves in the sheet, then co-firing the sheets, and then dividing the sheets into individual chip resistors. (2) The method for manufacturing a chip resistor according to claim 1, wherein the conductor paste and the resistor paste are formed by a screen printing method. (3) The method for manufacturing a chip resistor according to claim 1 or 2, wherein the simultaneous firing is performed at a temperature of 1000° C. or lower.