KR20020079618A - Fusible resistor and method of fabricating the same - Google Patents

Abstract

PURPOSE: A fuse resistor and a method for fabricating the same are provided to improve a resistor characteristic and a fusing characteristic without increasing a size of the fuse resistor though rated current is increased. CONSTITUTION: A conductive layer is deposited on a surface of a rod-shaped resistant body. A fusible element layer is deposited on a surface of the conductive layer. The fusible element layer is fabricated by a material including copper. An anti-oxide layer is deposited on a surface of the fusible element layer. The first structure is formed by the conductive layer, the fusible element layer, and the anti-oxide layer. The second structure is formed by installing a cap on both ends of the first structure. The fusible element layer is electrically connected to the outside by the cap. The third structure is completed by forming a spiral groove on the conductive layer, the fusible element layer, and the anti-oxide layer. A lead line(7) is adhered to an outside of the cap. A fuse resistor(40) is completed by forming a protective layer(8) on the third structure(30).

Description

Fuse resistor and its manufacturing method {FUSIBLE RESISTOR AND METHOD OF FABRICATING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuse resistor and a method of manufacturing the same.

Fuse resistors are intended to protect circuit elements contained in electronic equipment. They function as general resistors during stability and as circuit breakers due to blown-out characteristics during overload abnormalities.

In the conventional fuse resistor, a thin film layer made of a compound such as carbon, tin-nickel (Sn-Ni), nickel-chromium (Ni-Cr), or the like is deposited on the resistor by electroless plating, and then spiral cut on the surface thereof. , Also referred to as "trimming". Such a conventional fuse resistor can be manufactured at a relatively low cost, but it is known that it is impossible to form a resistance value of 0.1 kPa or less in the manufacturing method, and that the resistance is increased during trimming, so that it is not possible to manufacture a fuse resistor of 0.22 kPa or less. . For this reason, when a current of a specific value or more is applied to the circuit of the electronic device, there is a problem that the fuse resistor excessively generates heat. To overcome this, a method of increasing the rated power of a fuse resistor or using a micro fuse has been proposed. However, when the rated current of the fuse resistor is simply increased, the size of the fuse resistor is increased, and in the case of the micro fuse, there is a problem in that the cost is high in terms of unit productivity and material cost due to the structural characteristics of the product.

Accordingly, an object of the present invention is to solve such problems, and an object of the present invention is to provide an inexpensive fuse resistor and a method of manufacturing the same, which exhibit excellent resistance characteristics and fusing characteristics even when the rated current is not increased. It is.

According to a feature of the invention, a fuse resistor for protecting a circuit element included in an electronic device is provided. The fuse resistor includes a resistor, a fusible element layer formed to surround the resistor, a cap for electrically connecting both ends of the fusible element layer to the outside, a fusible element layer, and a cap. And an insulating layer for insulating.

According to another feature of the invention, a method of manufacturing a fuse resistor for protecting a circuit element included in an electronic device is provided. The method includes providing a resistor, forming a fusible element layer to surround the resistor, forming a cap that electrically connects both ends of the fusible element layer to the outside, the fusible element layer and the cap. Forming an insulating layer for insulating the.

1A to 1F are cross-sectional views illustrating step by step methods of manufacturing a fuse resistor according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: resistor

2: conductive layer

3: fusible element layer

4: antioxidant layer

5: cap

6: spiral groove

7: lead wire

8: protective film

Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

1A to 1F are cross-sectional views illustrating step by step methods of manufacturing a fuse resistor according to an embodiment of the present invention.

First, as shown in FIG. 1A, a conductive layer 2 made of a conductive material is laminated on the surface of a rod-shaped resistor 1. In the present embodiment, the resistor 1 is formed of a material such as high purity ceramic. Nickel-chromium (Ni-Cr) may be used as the conductive material, which is laminated on the surface of the resistor 1 by, for example, an electroless plating method used in a conventional fuse resistor manufacturing method.

Subsequently, a fusible element layer 3 having a fusing characteristic is laminated on the surface of the conductive layer 2 (FIG. 1B). In the present embodiment, the fusible element layer 3 is formed of a material containing copper (Cu), and in addition to copper (Cu), the material has a temperature coefficient of about 2,000 ppm / ° C or more, and the intrinsic resistivity is approximately 1.6 × 10 ^−8. Any material may be used as long as the material is as low as 1.8 × 10 ⁻⁸ Ω · m (ohm · meter). The fusible element layer 3 is melted and melted by heat generated when an overcurrent flows through the resistor 1. Here, the temperature coefficient is the most important material property that determines the fusing property. If the temperature coefficient is high, the resistance of the fusible element layer 3 increases due to the heat generated when the current rises. As a result, the temperature of the fusible element layer 3 is raised to the melting point by joule heat, and the fusible element layer 3 is melted. Copper used as the material of the fusible element layer 3 in this embodiment has a high temperature coefficient, a low resistivity, and a low melting point, so that it can act as an electrically excellent fuse.

Such a fusible element layer 3 may be deposited on the surface of the conductive layer 2 by an electrolytic plating method. As another method, the fusible element layer 3 may be deposited directly on the surface of the resistor 1 using a sputtering method or the like in addition to the electrolytic plating method. As described above, when the fusible element layer 3 is laminated without using the electrolytic plating method, the above-described conductive layer 2 can be omitted.

Thereafter, in order to prevent the fusible element layer 3 from being oxidized in the air, an antioxidant layer 4 is deposited on the surface of the fusible element layer 3 (FIG. 1C). For example, the anti-oxidation layer 4 may deposit silver paste using a spray method. Such an antioxidant layer 4 may be omitted, and a protective film such as a silicone paint, which will be described later, may be directly formed on the surface of the fusible element layer 3. However, since the fusible element layer 3 may be exposed to the atmosphere during the manufacturing process, it is advantageous to stack the antioxidant layer 4.

As described above, the final initial resistance of both ends of the first structure 10 formed of the three layers 2, 3, and 4 is determined according to the type and thickness of each layer. In the present embodiment, an extremely low resistance value of about 5 m 5 or less is determined. To form.

Subsequently, the cap 5 is installed to surround both ends of the structure 10 to form the second structure 20 (FIG. 1D). Through this cap 5, the fusible element layer 3 can be electrically connected to the outside. Resistance of both ends of the second structure 20 is maintained at about 3 ~ 4 mΩ.

Thereafter, as shown in FIG. 1E, the spiral grooves 6 are formed in the three layers 2, 3, and 4 to form the third structure 30. Final completion resistance of both ends of the third structure 30 is usually maintained at about 20 ~ 100 mΩ. This final completion resistance value is determined according to the final initial resistance value of both ends of the first structure 10 and the rotation speed of the helical cutting. More specifically, the final completion resistance value after the spiral cutting (trimming) is determined by the width of the spiral a, and provides the same characteristics as the rated current of the fuse according to the determined resistance value. According to the final completion resistance value, the characteristic corresponding to the rated current of the fuse or the like can be determined.

Finally, as shown in FIG. 1F, the lead wire 7 is attached to the outside of the cap 5 by welding or the like. This lead wire 7 electrically connects the fusible element layer 3 with the circuit board on which the fuse resistor is to be mounted. Thereafter, the outer side of the third structure 30 is coated with an insulating paint to form a protective film 8, thereby completing the fuse resistor 4 according to the present invention. Here, the protective film 8 insulates the fusible element layer 3 and the cap 5 from the outside and protects each component therein from external shocks. The outer surface of the protective film 8 is preferably formed of a nonflammable paint so as to display a rated current or the like.

According to the present invention as described above, by depositing a fusible element layer 3 made of a material such as copper on the surface of the resistor 1 with a temperature coefficient of about 2,000 ppm / ° C or more and a low intrinsic resistivity, approximately 20 It becomes possible to manufacture a fuse resistor having an extremely low resistance value of about 100 mΩ. As such, the fuse resistor having the extremely low resistance value does not generate excessive heat, and thus can perform all of the functions unique to the fuse.

In addition, since the present invention applies the conventional fuse resistor method also in the manufacturing method, it is possible to implement the present invention without investing in a specific equipment and to achieve high productivity.

Claims (2)

A fuse resistor for protecting a circuit element included in an electronic device, With a resistor, A fusible element layer formed to surround the resistor; A cap for electrically connecting both ends of the fusible element layer to the outside; An insulating layer for insulating the fusible element layer and the cap A fuse resistor comprising a. In the method of manufacturing a fuse resistor for protecting a circuit element included in the electronic device, Providing a resistor, Forming a fusible element layer to surround the resistor; Forming a cap electrically connecting both ends of the fusible element layer to the outside; Forming an insulating layer for insulating the fusible element layer and the cap Fuse resistor manufacturing method comprising a.