JPH1079301A - Chip type fuse resistor and its electrode structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the process of manufacture by a method wherein a resistance film, comprising a ruthenium material fuse part and a resistance part are formed on a glaze film, a fuse part, which is thinner and narrower than the resistance part, and a glass film is formed as a protective film. SOLUTION: An SiO2 glass film is printed on the whole surface of an alumina insulated substrate 1, and a glaze film 2 is formed by firing. A stripe ruthenium oxide film is formed on the upper surface of the glaze film 2 as a resistance film, and the fuse part 4 in the center part, which pertinents to an electrode part 7, is thinly formed and a resistance part 8 is thickly formed. A trimming trace 9 is formed on the resistance part 8. An Ag electrode 10 is laminated on the part ranging from above the electrode part 7 to the side face of the substrate 1, a glass film 11 is covered, as a protective film, on the entire surface of the Ag electrode 10 and the exposed resistance film 3, and besides, a terminal electrode 12 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type fuse resistor, and more particularly to a material for a resistive film having a fuse property and an electrode structure of the chip type fuse resistor.

[0002]

2. Description of the Related Art Heretofore, there has been a chip type fuse resistor in which a fuse portion and a resistor portion are separated by different materials, and ruthenium oxide (RuO ₂₎ is used as a resistor film of a simple chip type resistor having no fuse portion. ) -Based paste is used by printing and baking with a uniform thickness.

[0003] In the latter chip type resistor, ruthenium oxide consisting only of a resistive film is prevented from diffusing when the electrode is Au, Ag-Pt type or Ag-Pd type in relation to the electrode. Although it was meaningful for a simple chip-type resistor to prevent the deterioration of the resistance characteristics, in the case of a chip-type resistor with a fuse part, flames, fires, explosions, etc. occurred due to overload of the fuse part. However, this does not solve the problem of the chip type fuse resistor that damages other components on the integrated circuit substrate. In particular, the flaming, firing, and explosion of the fuse part are more serious in the recent years as the circuit size of electronic devices is reduced, and the above problems are amplified in conjunction with the reduction in the price of integrated circuits. doing.

In the former case, ruthenium oxide is used as a chip-type fuse resistor separated by a different material, but this is used only for the thick-film resistor portion of the fuse resistor, and is blown. As a conventional fuse portion, a metal organic paste such as gold, silver, platinum, rhodium, palladium, or the like is used as a thin film fusing portion, and different types of materials are separately functioned, and the fusing portion is not provided with ruthenium oxide. Therefore, in this conventional structure, the metal organic paste has a fusing function due to heat concentration in the fuse portion to prevent the occurrence of flame, and the thick film resistor portion uses ruthenium oxide. As a manufacturing method, the cost is unavoidable because the thick-film resistance portion is manufactured by a screen printing method and the thin-film fuse portion is manufactured by a separate process such as a screen printing method and / or a photo-etching method. In addition, it has a problem that it cannot cope with a high resistance value.

[0005]

There is an idea to make a fuse unit composed of a fuse portion and a resistance portion only with inexpensive ruthenium oxide. There is a fundamental drawback as a fuse.

On the other hand, it is difficult to increase the resistance value by using only the above-mentioned metal organic paste of gold, silver or the like having good fusing characteristics. Particularly, when the protective film is made of an organic resin, flaming frequently occurs. Become.

Therefore, the purpose of the chip type fuse resistor of the present invention is to simplify the manufacturing process by using one type of material for both the fuse part and the resistance part, and to compare with the metal organic paste in the case where only one type is used. Poor fusing characteristics in the fuse area are compensated for by forming a material layer with low thermal conductivity on the insulating substrate, and the protective film is made of glass, preventing flames and other problems, improving mass productivity. By doing so, we will provide an inexpensive chip-type fuse resistor that meets the needs of the market.

Another object of the present invention is to provide a resistive film made of one kind of ruthenium-based material based on the above-mentioned object, and to reduce the fusing property of ruthenium by reducing the thickness of a fuse portion and a resistor portion on an insulating substrate. The difference was compensated for, and the fusing characteristics (rapid cutting performance and resistance value) were improved by using a ruthenium-based material.

Another object of the present invention is to prevent the occurrence of a flame or the like in the protective film due to the heat concentration of the fuse portion.

Another object of the present invention is to form a glaze layer having a reduced thermal conductivity on a surface of an insulating substrate in the form of a layer of a ruthenium-based material to form a layer of Ag, Ag-Pd, gold, a platinum alloy paste, or the like. Provided is a chip-type fuse resistor which has good adhesion to an electrode and good plating properties on the electrode.

Still another object of the present invention is to form a layer structure of an electrode of a fuse resistor and to form an Ag-based electrode layer on a glaze layer on an insulating substrate. The problem is solved by interposing a ruthenium-based material layer between them, and furthermore, since the ruthenium-based material is applied on the entire surface of the insulating substrate in the same manner as the resistive film on the glaze layer, a new process in the electrode portion is not required. We also considered that production could be improved.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and its gist is to provide an insulating substrate, a protective film, and a fuse portion and a resistor portion sandwiched therebetween. A chip-type fuse resistor including a resistive film having a fuse property and electrodes located at both ends of the resistive film,
A chip, wherein a grace layer is formed on the insulating substrate, and the resistive film thereon is a thin film fuse portion and a thick film resistive portion is made of a ruthenium-based material, and the protective film is a glass film. Type fuse resistor.

Here, as the insulating substrate, alumina ceramic, mullite, aluminum nitride, or the like having slits on one or both surfaces is used.

The protective film is not made of a conventionally used synthetic resin such as an epoxy resin or a phenol resin, but is made of CaO.
-BaO-SiO ₂ system and CaO-Al ₂ O ₃ using a glass film of -SiO ₂ system.

As the resistive film having the fuse property, one kind of each of ruthenium-based materials such as lead ruthenate and bismuth ruthenate is used because of its quick cutting property and the increased resistance value. The width is smaller than the resistance part and / or the film thickness is smaller than the resistance part. Assuming that the widths of the fuse portion and the resistor portion are substantially the same, the film thickness of the former is 3 μm.
10 μm to 10 μm (If it is 3 μm or less, the rated current cannot be
If it is 0 μm or more, it is difficult to obtain a fuse function such as blowing).
By increasing the thickness by μm, good fusing characteristics can be obtained. In this case, if it is 5 μm or less, the durability is poor, and if it is 10 μm or more, the quick-breaking property is poor.

The glue layer may be made of CaO, SiO ₂ or a mixture thereof.

Further, examples of the ruthenium-based material include ruthenium oxide having a pyrochlore structure in addition to rutile oxide having a rutile structure.

According to another aspect of the present invention, there is provided an insulating substrate;
A chip-type fuse resistor comprising: a protective film; a resistive film having a fuse portion and a resistive portion sandwiched therebetween; and electrodes located at both ends of the resistive film. Characterized in that a ruthenium-based material is formed on a glaze layer of an insulating substrate, an Ag-based film is formed thereon, and a plating layer of a tin-lead alloy or the like is further formed on the uppermost layer. There is an electrode structure of the vessel.

Here, the Ag-based film includes Ag alone as well as Ag alone.
-Pt, Ag-Pd and the like.

[0020]

In order to reduce the thermal conductivity by forming a glaze layer on an insulating substrate so that heat is concentrated on the fuse portion, the resistance value can be increased even if the upper layer is made of a ruthenium material alone. A chip type fuse resistor having excellent fusing characteristics can be obtained. Further, even if the fuse portion generates heat due to the contact of the ruthenium-based material with the glaze layer, smoking and ignition are prevented by using a glass film for the upper protective film of the ruthenium-based material. When a fuse portion is made of a ruthenium-based material, the thickness is preferably 3 μm to 10 μm in view of the fusing characteristics. However, in order to increase the residual resistance, it is preferable that the thickness of the fuse portion be 5 to 15 μm thinner than that of the resistance portion. Here, if the thickness is less than 5 μm, the fuse is cut by energization.

Further, by forming the electrode structure on the insulating substrate from the bottom with a glaze layer, a ruthenium-based material layer, and an Ag-based thick film, an effect of improving the adhesion to the glaze layer as an electrode can be obtained. In particular, by bringing the glaze layer and the ruthenium-based material layer into contact with each other and joining the Ag-based thick film on the ruthenium layer, the adhesion between them and the plating property on the Ag-based film are improved.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a chip type fuse resistor according to the present invention, and FIG. 2 is a sectional view taken along line AA of FIG.

In the chip type fuse resistor according to the present invention, an SiO ₂ glass film as the glaze film 2 is printed on the entire surface of the alumina insulating substrate 1 by screen printing and fired.

On the upper surface of the glaze film 2, ruthenium oxide (RuO ₂ ) as a resistive film is formed in a strip shape except for both side portions 5 and 6, and the fuse portion 4 at the center portion of the film and the electrode portions 7 at both ends are formed. The corresponding portion is thinned to a thickness of 3 μm to 10 μm, and the resistance portion 8 therebetween is further formed to a thickness of 5 μm to 15 μm. The resistance portion 8 has a trimming mark 9.

The Ag electrode 10 is laminated on the electrode portions 7 at both ends of the resistance film 3 to the side of the substrate, and a part of the electrode 10 and the exposed resistance film 3
The whole surface of CaO—Al ₂ O ₃ − as protective film glass 11
It is covered with SiO ₂ .

Further, the protective film glass 11 is applied to both ends of the alumina substrate 1 by dipping or applying rollers.
The Ag electrode 10 is partially exposed between the
Form 2

Further, the entire surface of the end face electrode 12 and the partially exposed Ag electrode 10 are covered with a plating film of nickel and a tin-lead alloy.

The procedure for manufacturing the chip type fuse resistor of the present invention having the above-described structure will be described with reference to FIG.

First, an SiO ₂ glass paste is printed on the alumina substrate 1 by screen printing (S
1). Then, the printed material is fired to form the glaze film 2 (S2).

Next, ruthenium oxide 3 is screen-printed on the SiO ₂ -based glaze film 2, in the form of a film portion (fuse portion) 4 having a thinner film at the center and a film portion (fuse portion) having a thin film at both ends. It is assumed that the Ag electrode mounting portion 10 and the resistor portion 8 having a large thickness with respect to the thin film portion are formed in an uneven shape (S3). Although this unevenness can be technically performed by one screen printing in which the application amount is changed by changing the screen pattern, it is also possible to perform multiple times of lamination printing. Then, the printed material is fired (S4).

Further, an Ag electrode 10 is printed on the thin film portions 7 at both ends of the ruthenium oxide (S5) and fired (S6).

After the electrode 10 is formed in this manner, trimming 9 is performed on the resistance portion 8 of the resistance film 3 made of ruthenium oxide (S7).

A lead borosilicate-based protective glass is printed on the resistive film 3 and a part of the electrode 10 (S8) and baked (S8).
9).

Thereafter, the insulating substrates of a number of chip type fuse resistors are vertically cracked (S10), and the cracked end surface is coated with an end electrode 12 by a roll or dipping method and printed (S11), and then baked ( S12) Further, the chips are cracked laterally to form one individual fuse resistor chip (S13), and a plating film is applied to many of these chips (S14). Finally, quality inspection is performed to complete the chip (S1).
5).

[0036]

As described above, according to the present invention, a glaze layer is formed on an insulating substrate, and a thin or / and narrow fuse portion and a thick or / and thicker fuse portion than a fuse portion are formed thereon as a resistive film. In addition, since the single-sided ruthenium-based material is applied to the wide resistor section at a time, the manufacturing process is simplified, and the use of expensive gold or silver organic paste is eliminated, resulting in low cost and mass productivity. An excellent chip type fuse resistor is obtained.

Further, since the fusing characteristics are not good only by using a ruthenium-based material for the fuse portion, a glaze layer is provided on an insulating substrate and then the ruthenium-based material is formed into a layer to improve this.

Further, even if the fuse portion of ruthenium becomes high in temperature, the protective film is made of a glass layer, so that it is possible to prevent flaming and firing.

The thickness of the fuse portion using ruthenium is set to 3
By setting the thickness to between 10 μm and 10 μm, the quick-breaking property is improved, and by providing a resistor portion having a thickness of 5 μm to 15 μm further than this film thickness, the residual resistance of the entire fuse is increased, thereby improving the performance.

Further, since the electrode structure of the chip type fuse resistor of the present invention is made of a ruthenium-based material in the lower layer, an Ag-based film on the lower layer, and a tin-lead alloy plating film on the uppermost layer, This has the effect of improving the reliability (adhesion) of the electrode.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a chip type fuse resistor according to the present invention and its electrode structure.

FIG. 2 is a sectional view taken along line A-A 'of FIG.

FIG. 3 is a flowchart showing a manufacturing procedure of the chip resistor of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Alumina substrate 2 Glaze film 3 Resistance film (ruthenium) 4 Fuse part of resistance film 7 Both ends of resistance film 8 Resistance part of resistance film 9 Trimming (trace) 10 Electrode (Ag) 11 Protective film glass 12 Edge electrode 13 Plating film (Tin-lead alloy)

Claims (3)

[Claims] 1. A chip comprising an insulating substrate, a protective film, a resistive film having a fuse portion and a resistor portion sandwiched therebetween, and having a fuse property, and electrodes located at both ends of the resistive film. A fuse resistor, wherein a grace layer is formed on the insulating substrate, and the fuse portion and the resistor portion of the resistive film thereon are made of a ruthenium-based material having a thinner and / or narrower width than the latter, and A chip-type fuse resistor, wherein the protective film is a glass film. 2. The fuse section of the resistance film has a thickness of 3 μm.
10 μm to 10 μm.
2. The chip-type fuse resistor according to claim 1, wherein the thickness of the chip-type fuse resistor is increased by μm. 3. A chip comprising an insulating substrate, a protective film, a resistive film having a fuse portion and a resistive portion sandwiched between them, and a resistive film having electrodes and electrodes located at both ends of the resistive film. Wherein the electrode is a ruthenium-based material on a grace layer of the insulating substrate, and an Ag-based material on the ruthenium-based material.
An electrode structure for a chip type fuse resistor, comprising a base film and a plating film formed thereon.