JP2964478B2 - Surface mount type chip fuse resistor and method of manufacturing the same - Google Patents

Description

The present invention relates to a surface-mounted chip-type fuse resistor and a method of manufacturing the same.

(Prior art) Conventional surface mount chip type fuse resistors are disclosed in
As described in JP-A-62-55832, a resistive film is formed between electrodes on a chip-shaped insulating substrate, a fusing portion is formed on the resistive film by trimming, and a gap between the fusing portion and the insulating substrate is formed. There has been known a structure in which a heat insulating layer made of glass is interposed in the substrate, and the fusing time of the resistive film when an overcurrent occurs is shortened by the concentration of load by trimming and the heat insulating property of the glass.

Also, as a method of manufacturing a chip-shaped fuse resistor,
As described in the above-mentioned JP-A-62-55832, a pair of electrodes is formed at intervals on each unit piece on an insulating substrate having a dividing groove, and then a pair of electrodes is formed at an intermediate portion of the electrodes. A glass heat insulating layer is formed, a mask is applied to the entire surface other than the resistance film forming portion including the glass heat insulating layer with a plating resistant paint, then, an electroless nickel plating is performed to form a resistance film, and the mask is peeled off, After aging, the resistance film is trimmed to adjust the resistance value and to form a portion that is easily blown when an overcurrent occurs.

Then, after sequentially forming the surface protective film, a method is adopted in which the insulating substrate is divided into strip-shaped elongated plates, end electrodes are formed in the length direction of the elongated plates, and the elongated plates are divided into chips. ing.

(Problems to be Solved by the Invention) However, in the chip-shaped fuse resistor having the structure described in JP-A-62-55832, the fusing speed of the resistive film is reduced due to the load concentration by trimming and the heat insulating property of the glass. However, since a heat insulating layer made of glass is interposed between the fusing portion and the insulating substrate, it is difficult to prevent the resistance film from re-contacting after fusing.

Further, according to the method for manufacturing a chip-shaped fuse resistor described in JP-A-62-55832, a large number of electrodes are first formed on an insulating substrate, and then a glass heat insulating layer is formed between the electrodes. Since the resistance film is formed, there is a problem that a step is formed in a heat insulating layer or a connection portion between the electrode and the resistance film, and it is difficult to make the resistance film uniform.

The present invention has been made in view of the above problems, and a surface-mounted chip-type fuse resistor capable of easily forming a uniform resistance film while preventing re-contact when the resistance film is blown when an overcurrent occurs, and a device therefor. It is intended to provide a manufacturing method.

According to a first aspect of the present invention, there is provided a surface-mounted chip-type fuse resistor, comprising an alumina square insulating chip piece, and an activation treatment film containing palladium as a main component formed on the chip piece. Layer, a resistive film containing nickel as a component formed by electroless plating on the upper surface of the activation treatment film layer, and a pair of upper surfaces formed separately from each other on both ends of the upper surface of the resistive film on the chip piece. An electrode, a load concentrating portion formed by a kerf formed by laser trimming on the resistive film between the upper electrodes, and an insulating and heat-insulating material of a low melting point material made of a non-carbonized resin coated on the load concentrating portion. Material, an end face electrode formed continuously from both end faces of the chip piece to the upper face of the upper face electrode and the back face of the chip piece, and a solder electrode covering the end face electrode. And a protective coat made of a heat-resistant epoxy resin formed on the upper surface of the resistive film between the upper electrodes of the chip pieces.

According to a second aspect of the present invention, there is provided a method of manufacturing a surface-mounted chip-type fuse resistor, wherein a dividing groove for dividing into chip pieces is formed vertically and horizontally on a surface of an alumina insulating substrate. Activating paste is printed and baked at both ends of the resistive film forming position divided into chip pieces on the same surface as the dividing groove to form an activated treatment film layer containing palladium as a main component. A resistive film containing nickel as a component is formed on the resistive film by electroless plating, and a pair of upper electrodes which are spaced apart from each other are formed on the resistive film for each chip piece unit, and each chip piece unit is formed. Forming a load concentrating portion by kerf on the resistance film by laser trimming, and printing a coating made of a resin that does not carbonize on the load concentrating portion; The resistive film is coated with a heat-resistant epoxy resin paint and coated with a protective coat formed by heat curing, and the insulating substrate coated with the protective coat is divided into strips by dividing the vertical dividing grooves. An elongated plate having a shape of a circle is formed, and an end surface electrode is continuously formed from an end surface of the elongated plate to an upper surface of the upper surface electrode and a back surface of the elongated plate. It is divided into square chips by the dividing grooves to form solder electrodes covering the end face electrodes.

(Function) In the surface-mounted chip-type fuse resistor according to the first aspect of the present invention, the palladium of the activation treatment film layer is formed by the activation treatment film layer mainly composed of palladium formed on the alumina insulating chip piece. A resistive film that forms a nucleus and contains nickel as a component formed by electroless plating is firmly bonded to the alumina insulating chip piece, and the resistive film and the top electrode come into surface contact, resulting in low contact resistance and a small contact resistance between the resistive film and the top electrode. There is no generation of Joule heat due to poor contact between the parts, and the load concentrated part due to the kerf formed by laser trimming on the resistive film between the upper electrodes becomes easier for heat to concentrate, and the molten insulating material that melts Low melting temperature due to low melting point material made of non-carbonized resin, shortening the fusing time of resistive film when overcurrent occurs, no carbon remains after melting, causing carbonization Even if the resistance film is blown out, there is no electrical conduction due to the penetration of carbon into the gaps of the internal particles, the resistance film blown out by the molten material due to heat concentration does not re-contact, and the end face electrode is It is formed continuously from both end surfaces of the chip piece to the upper surface of the upper surface electrode, and the resistance coating and the end surface electrode have low contact resistance. The connection between the continuous end face electrode and the resistive film between the upper electrodes of the chip piece is ensured, and the resistive film is surely protected by a protective coat made of a heat-resistant epoxy resin.

A method for manufacturing a surface-mounted chip-type fuse resistor according to claim 2, wherein the dividing grooves for dividing the alumina insulating substrate into chip units are formed at both end resistance film forming positions on the same surface as the chip surface on which the dividing grooves are formed vertically and horizontally. By printing and firing the activation paste, an activation treatment film layer containing palladium as a main component can be easily formed, and nickel is used as a component by electroless plating on the palladium nucleus formed in the activation treatment film layer. The resistive film containing is firmly bonded to the insulating substrate, a uniform resistive film is easily formed, and there is no generation of Joule heat due to poor contact between the resistive film for each chip piece and each pair of upper electrodes. Heat easily concentrates on the load concentrated part due to the kerf formed by laser trimming on the resistive film between the upper electrodes, and when overcurrent occurs, heat concentrates on the load concentrated part and shortens the fusing time of the resistive film. The melting material that can be shrunk and melted by heat concentration has a low melting point made of a resin that does not carbonize. Even if it is blown, there is no electrical conduction due to the penetration of carbon into the gaps between the internal particles, and the resistance film that is blown by the molten material due to heat concentration does not re-contact, and the resistance film that is blown by the molten material re-contacts The protective film protects the resistance film with a protective coat, and since this protective coat is formed by applying a heat-resistant epoxy resin paint and curing by heat, it is easy to form a protective coat and coat this protective coat. The insulated substrate is divided from the vertical dividing grooves to form end-face electrodes continuously from the end face of the strip-shaped strip to the upper surface of the upper electrode and the back face of the strip. Therefore, the end face electrodes of a plurality of chip pieces can be formed efficiently at the same time, the end face electrodes are continuously formed from both end faces of the chip piece to the upper surface of the upper face electrode respectively, and the contact resistance between the resistive film and the end face electrode is small, In the state where the end surface electrode is continuous to the back surface of the chip piece, the connection between the end surface electrode continuous on the back surface and the resistive film between the top electrode of the chip piece in a state of being surface-mounted is ensured,
By dividing the elongated plate on which the end face electrodes are formed into chips by dividing grooves in the horizontal direction, the chip pieces can be easily formed. Further, since the dividing groove, the activation treatment film, the resistance film, the upper surface electrode, and the protective coat are formed on the same surface, the production becomes easy.

(Embodiment) Hereinafter, a configuration of an embodiment of a surface-mounted chip-type fuse resistor of the present invention will be described with reference to FIGS. 1 and 2. FIG.

Reference numeral 1 denotes a chip piece obtained by dividing an alumina insulating substrate, for example.
An activation treatment film layer 2 containing palladium (Pd) as a main component is formed on the chip piece 1, and a nickel-phosphorus (Ni-P) -based, nickel-boron (Ni-
B), copper (Cu), nickel-tungsten (Ni-
The resistive film 3 containing nickel as a component such as W) is formed by electroless plating. Furthermore, this resistance film 3
Silver (Ag) -resin paste is baked or nickel-chromium (Ni
-Cr), copper (Cu) based upper surface electrodes 4,4 are formed respectively.

Further, the resistance film 3 between the upper electrodes 4, 4 is provided with a kerf 5 double-reverse cut by laser trimming.
A load concentrating portion 6 is formed, and a molten material 7 such as a non-carbonized resin, for example, a cellulose resin, which is a low melting point material having insulation and heat insulating properties, is formed on the load concentrating portion 6. Further, if necessary, a kerf 8 for adjusting a resistance value is formed in the resistance film 3 by laser trimming. Further, on the resistance film 3 including the molten material 7,
A protective coat 9 made of a heat-resistant epoxy resin is formed.

Then, the end surface electrode 1 made of the same material as the upper surface electrodes 4, 4 continuously extends over both end surfaces and a part of the back surface of the chip piece 1 and the upper surfaces of the upper surface electrodes 4, 4 not covered with the protective coat 9.
0, 10 are formed, and further, solder electrodes 11, 11 are formed so as to cover the end face electrodes 10, 10, so that a chip-shaped fuse resistor is formed.

Next, the manufacturing method of the chip-shaped fuse resistor is described in a third method.
This will be described with reference to FIGS.

(1) In FIG. 3, reference numeral 12 denotes an insulating substrate made of alumina.
On the surface of the insulating substrate 12, dividing grooves 13, 14 are formed vertically and horizontally for each chip piece unit 1a.

Then, as shown in FIG. 3 and FIG.
The activation paste is printed on the surface of 12 in a strip shape continuously in the longitudinal direction of the length direction of each chip piece unit 1a, 500 to 600 ° C
To form the activation film layer 2 in the surface length direction of each chip piece unit 1a. As the activation paste for the activation treatment film layer 2, an organic binder paste containing palladium (Pd) as a main component or a glass binder paste containing palladium (Pd) as a main component is used.

(2) Next, as shown in FIGS. 5 and 6, the activation film layer 2 of the insulating substrate 12 is subjected to electroless plating to form a resistance film 3. The resistance film 3 is made of nickel-phosphorus (Ni-P), nickel-boron (Ni-B), copper (C
u) -based or nickel-tungsten (Ni-W) -based electroless plating solution containing nickel as a component so that the insulating substrate 12 is immersed in the electroless plating solution. The coating containing nickel as a component is firmly bonded to the nucleus by electroless plating, and the plating solution in the portion where the activation treatment film layer 2 is not formed is washed away. Then, aging is performed to form the resistive film 3 on the activation processing film layer 2 of each chip piece unit 1a.

(3) Further, as shown in FIGS. 7 and 8, the resistance film 3 on the upper surface of the chip piece unit 1a on which the resistance film 3 is formed.
A pair of upper surface electrodes 4, 4 are formed at both ends including. The upper electrodes 4 are formed by printing silver (Ag) -resin paste on the electrode forming portion and baking at 150 to 200 ° C.
Alternatively, it is formed by masking the other part of the electrode forming portion with a metal mask or a resist, and sputtering nickel-chromium (Ni-Cr), copper (Cu), or the like on the electrode forming portion.

(4) Next, as shown in FIG. 9 and FIG.
Is formed by laser trimming to form a load concentrating portion 6 by the cut groove 5 and a cut groove 8 for resistance value adjustment by laser trimming.

(5) Next, as shown in FIG. 11 and FIG.
A coating made of a non-carbonized resin of a low melting point material having insulating and heat insulating properties is printed on the load concentrating portion 6 to form a molten material 7.

(6) Next, as shown in FIGS. 13 and 14, the resistive film 3 including the molten material 7 is continuously formed in a strip shape on the insulating substrate 12 and covered with a heat-resistant epoxy resin paint. To form a protective coat 9.

(7) Next, as shown in FIG. 15, the insulating substrate 12 is divided by a vertical dividing groove 13 which is the longitudinal direction of the chip unit 1a, and the chip unit 1a is continuous in the width direction. The elongated divided plate 1b, which is the elongated plate of the above, is formed.

(8) Further, as shown in FIG. 16, silver (Ag)-is added to the entire length of both sides of the elongated divided plate 1b, which is an elongated plate, and a part of the upper surface and the lower surface of the upper electrode 4 continuous on both sides. A resin paint is applied and baked, or a nickel-chromium (Ni-Cu) or copper (Cu) -based metal film is formed by sputtering, and the end face electrodes 10 and 10 connected to the top electrodes 4 and 4 are formed. Form.

(9) Then, the elongated dividing plate 1b is divided by the lateral dividing grooves 14 in the width direction of the chip unit 1a.
The chip piece 1 shown in the figure is formed.

(10) Next, nickel (N
i), tin / lead (Sn / Pb) solder material is plated to form solder electrodes 11, 11 to obtain a product of the surface-mounted chip-type fuse resistor shown in FIGS. 1 and 2.

Next, the operation of the surface mounted chip type fuse resistor of the above embodiment will be described.

When the chip-shaped fuse resistor of the above-described embodiment is used by surface-mounting it on an electronic component circuit such as a transistor or an IC,
There is no generation of Joule heat due to poor contact between the resistive film 3 of each chip piece 1 and each pair of upper electrodes 4, and heat concentrates on the load concentrating portions 6 by the cut grooves 5 of the resistive film 3 between the upper electrodes. When an overcurrent occurs, the load concentrating portion 6 of the resistance film 3 is overheated and the resistance film 3
No Joule heat is generated due to poor contact between the upper electrode 4 and each pair of upper electrodes 4, and the heat is concentrated on the resistive film 3 between the upper electrodes 4 due to the heat insulating effect of the molten material 7 when an overcurrent occurs. 6, the molten material 7 is quickly melted by the heat concentration, and the melting time of the resistance film 3 can be shortened. In addition, even if the resistance film 3 melted by the molten material 7 does not come into contact again, no carbon remains after melting and the cause of carbonization does not occur, and the resistance film 3 melts, the carbon penetrates into the gap between the internal particles. As a result, there is no electrical continuity, and re-contact of the resistive film 3 blown by heat concentration can be prevented.

Further, by forming the resistance film 3 on the insulating substrate 12 by electroless plating with the activation treatment film layer 2 as a base,
Next, since the upper electrodes 4, 4 were formed on the resistance film 3,
The contact portion of the resistance film 3 with the upper surface electrode 4 is in surface contact, and a uniform resistance film 3 can be easily formed.

Further, the activation treatment film layer 2 can be easily formed by printing and baking an activation paste, and the palladium nuclei formed in the activation treatment film layer 2 containing palladium as a main component are formed by electroless plating. The resistance film 3 containing nickel as a component is firmly bonded to the insulating substrate, and a uniform resistance film 3 is easily formed.

Further, since the resistance film 3 is formed by electroless plating with the activation treatment film layer 2 as a base, there is no need to mask the insulating substrate 12 when the resistance film 3 is formed, so that the production can be simplified.

Further, the activation substrate 2, the resistive film 3, the upper electrode 4, and the protective coat 9 are formed on the surface of the insulating substrate 12 where the dividing grooves 13 and 14 are formed. 13a and 14a and a chip piece unit 1a as compared with the case where the activation treatment film layer 2, the resistance film 3 and the upper surface electrode 4 are provided on the opposite surfaces.
Each of them is easy to manufacture, can be easily and substantially uniformly divided into chips, and the characteristics between products can be almost constant to improve the yield.

(Effects of the Invention) According to the first aspect of the present invention, a resistance film containing nickel as a component is firmly bonded to an activation treatment film layer on an alumina insulating chip piece, and the resistance film and the upper surface electrode come into surface contact, Low contact resistance and no Joule heat due to poor contact between the resistive film and the upper electrode. Heat is more likely to be concentrated on the load concentrated part due to the kerf formed by laser trimming on the resistive film between the upper electrode. In addition, the molten material has a low melting point due to the low melting point material made of non-carbonized resin, and the load concentration part can reduce the fusing time of the resistance film when overcurrent occurs. Due to the substance, carbon does not remain after dissolution, and there is no electrical conduction due to the penetration of carbon into the gaps of the internal particles even if the resistance film is blown without causing the cause of carbonization, The end face electrode is formed continuously from both end faces of the chip piece to the upper surface of the upper face electrode, respectively, without the re-contact of the resistance film melted by the molten material, and the contact resistance between the resistance film and the end face electrode is small. With the surface mounted by the end face electrode that continues to the back side of the chip piece, the connection between the end face electrode that is continuous on the back side and the resistive film between the top electrode of the chip piece is ensured, and furthermore, with the protective coat made of heat resistant epoxy resin The resistive film is reliably protected.

According to the second aspect of the present invention, the activation treatment film layer can be easily formed at the position where both ends of the alumina insulating substrate are divided into chip pieces on the surface where the dividing grooves for dividing the chip pieces are formed vertically and horizontally. The resistive film is firmly bonded to the insulating base, and a uniform resistive film is easily formed. Joule heat is generated due to poor contact between the resistive film of each chip piece and each pair of upper electrodes. In addition, heat is easily concentrated at the load concentrated part due to the kerf formed by laser trimming on the resistive film between the upper electrodes, and the heat concentration can reduce the fusing time of the resistive film when overcurrent occurs. Because there is no electrical conduction due to the penetration of carbon into the gaps of the internal particles even if the resistance film is blown off without causing carbonization after melting due to the low melting point substance made of resin that does not carbonize, The resistive film that is melted by the molten material does not re-contact, the resistive film can be reliably protected by the protective coat and the protective coat can be easily formed, and the end electrodes of a plurality of chip pieces can be formed simultaneously and efficiently. Are formed continuously from both end surfaces of the chip piece to the upper surface of the top electrode, respectively.The contact resistance between the resistive film and the end electrode is low. The connection between the end face electrode and the resistive film between the top electrodes of the chip piece is
By dividing the elongated plate on which the end surface electrodes are formed into chips by dividing grooves, chip pieces can be easily formed. Further, since the dividing groove, the activation treatment film, the resistance film, the upper surface electrode and the protective coat are formed on the same surface, the production can be simplified and the production becomes easy. In addition, since the dividing groove, the activation film, the resistive film, the upper electrode, and the protective coat are formed on the same surface, they can be divided into chips uniformly and easily, and stable characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a surface mount type chip-type fuse resistor of the present invention, FIG. 2 is a plan view of the same, FIG. 3 to FIG. FIG. 4 is a cross-sectional view taken along the line AA in FIG. 4, FIG. 5 is a plan view of a part of the insulating substrate on which a resistive film is formed, and FIG. 7 is a plan view of a part of the insulating substrate on which the upper electrode is formed, and FIG.
9 and 10 are plan views of a part of the insulating substrate obtained by trimming the resistive film, FIG. 11 is a plan view of a part of the insulating substrate formed with a molten material, and FIG. FIG. 13 is a cross-sectional view taken along the line BB in FIG. 13, FIG. 13 is a plan view of a part of the insulating substrate provided with a protective coating, FIG. 14 is a cross-sectional view taken in the line AA in FIG. 16, FIG. 16 is a plan view of an elongated divided plate on which an end face electrode is formed, FIG. 17 is a plan view of a divided chip piece, and FIG. 18 is a vertical sectional front view of the same. DESCRIPTION OF SYMBOLS 1 ... Chip piece, 1a ... Chip piece unit, 1b ... Slender divided plate which is an elongated plate, 2 ... Activation treatment film layer, 3 ... Resistive film, 4 ... Top electrode, 5 ... Cut groove , 6 ... Load concentration part,
7 ... molten material, 9 ... protective coat, 10 ... end face electrode, 11
…… Solder electrode, 12 …… Insulating substrate, 13,14 …… Division groove.

Continuation of the front page (72) Inventor Shiro Ota 3672 Ina, Ina-shi, Nagano Koa Co., Ltd. (56) References JP-A-52-48045 (JP, A) JP-A-55-157207 (JP, A) JP-A-63-14402 (JP, A) JP-A-53-64237 (JP, U)

Claims (2)

(57) [Claims] 1. An alumina-insulated square chip, an activation film layer mainly composed of palladium formed on the chip chip, and nickel formed by electroless plating on the upper surface of the activation film layer. A resistive film containing as a component, a pair of upper surface electrodes formed to be spaced apart from both ends of the upper surface of the resistive film on the chip piece, and a kerf formed by laser trimming in the resistive film between these upper surface electrodes A load concentrating portion, a heat insulating insulating material of a low melting point material made of a resin that is formed on the load concentrating portion and is not carbonized, and an upper surface of the upper surface electrode and an upper surface of the chip piece from both end surfaces of the chip piece, respectively. An end surface electrode formed continuously to the back surface; a solder electrode covering the end surface electrode; and a heat resistant electrode formed on the upper surface of the resistive film between the upper surface electrodes of the chip piece. Surface mount chip-like fuse resistors, characterized by comprising a protective coating consisting of carboxymethyl resin. 2. A split groove for dividing into chip units is formed vertically and horizontally on the surface of an alumina insulating substrate, and both ends of the insulating substrate formed with the split grooves are divided into chip units on the same plane as the split grooves. An activation paste is printed and baked at the resistive film forming position to form an activation-treated film layer containing palladium as a main component, and a resistive film containing nickel as a component is formed on the activated treatment film layer by electroless plating. Forming a pair of upper electrodes spaced apart from each other on the resistance film for each of the chip pieces; and forming a load concentration portion by a kerf on the resistance film for each of the chip pieces by laser trimming. A coating made of a non-carbonized resin is formed on the load concentrating portion, and coated with a low-melting-point insulating and heat-insulating molten material formed on the load concentration portion, and a heat-resistant epoxy resin coating is formed on the resistance film. The insulating substrate coated with the protective coat is divided from the vertical dividing groove to form a strip-shaped strip, and the end face of the strip is formed from the end face of the strip. An end electrode is formed continuously from the upper surface of the upper electrode to the back surface of the elongated plate. The elongated plate on which the end electrode is formed is divided into square chips by the lateral dividing grooves. A method for manufacturing a surface-mounted chip-type fuse resistor, comprising: forming a solder electrode for covering a chip.