JPH0636675A - Fuse resistor and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a flat chip fuse resistor of low fusing power. CONSTITUTION:A resistor 30 of a predetermined size is formed on one side of an insulating substrate 10 of a predetermined size and a fusing element 31 of a predetermiend size is formed with its portion near one end overlapping the portion near one end of the resistor 30. Electrodes 20, 21 are so formed to overlap the portion near the other end of the resistor 30 and the portion near the other end of the fusing element 31, respectively, and the resistor 30 is trimmed. Further, a heat storage layer is formed to almost cover the fusing element 31. Therefore, the resistor and the fuse element can be made independent of each other.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fuse resistor,
In particular, it relates to its structure and its manufacturing method.

[0002]

2. Description of the Related Art A conventional surface mount square chip fuse resistor has a structure as shown in FIG. Note that FIG.
FIG. 8A is a perspective view of a conventional square chip fuse resistor, FIG.
8B is a cross-sectional view taken along the line AA of FIG. The conventional square chip fuse resistor has a resistor 13 on the insulating substrate 110.
0 was formed, and electrodes 120 and 121 were formed so as to cover both ends of the resistor 130. The substantially central portion of the resistor 130 was provided with notches 130a and 130b in the direction of blocking the current path by trimming. The cutouts 130a and 130b set the resistance value of the square chip fuse resistor, and the fuse point 13
0c is formed, the cuts 130a and 130b and the fusing point 130c are cut into the heat storage glass layer 141.
To prevent the heat generated at the housing point 130c from being dissipated.

Electrode 12 of a conventional square chip fuse resistor
When an excessive current flows between 0 and 121, the fusing point 130c with a high current density rapidly generates heat, and the fusing point 130c melts.

[0004]

However, the above conventional example has the following problems. That is, in the conventional square chip fuse resistor, the resistance value adjustment and the forming of the fusing point 130c are performed at the same time, so if the resistance value adjustment is set with priority, the setting of the fusing power value becomes rough, and conversely, If the fusing power value is preferentially set, there is a drawback that the resistance value is roughly set.

Further, in the conventional square chip fuse resistor, since the cross-sectional area of the current path at the fusing point 130c formed by trimming is not uniform, the width of the fusing point 130c is further narrowed to lower the fusing power. When power is used, a portion having an extremely narrow current path cross-sectional area is generated, and there is a drawback that the surge resistance is deteriorated. Therefore, in the conventional square chip fuse resistor, there is a limit to lowering the fusing power, for example, the fusing current is 2
In the case of the conventional fuse fuse of [A], its fusing power is 2
It was difficult to reduce it below [W].

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and has the following structure as one means for solving the above problems. That is, in a fuse resistor formed on an insulating substrate of a predetermined size, a resistor layer of a predetermined size formed on one surface of the insulating substrate, and one end portion of the resistor layer near the one end portion thereof. A fuse element formed so as to overlap and at least one formed so as to overlap near the other end of the resistor layer.
A fuse including: one first electrode portion, at least one second electrode portion formed so as to overlap in the vicinity of the other end of the fuse element, and a heat storage layer formed so as to substantially cover the fuse element. Use as a resistor.

Further, a fuse forming step of forming a resistor layer of a predetermined size on one surface of an insulating substrate of a predetermined size, and a fuse element so that the one end portion of the resistor layer is overlapped with the one end portion thereof. A fuse element forming step for forming
At least one first electrode portion is formed so as to overlap with the other end portion of the resistor layer, and at least one second electrode portion is formed so as to overlap with the other end portion of the fuse element. A method of manufacturing a fuse for a fuse comprising a step of forming an electrode portion and a step of forming a heat storage layer so as to substantially cover the fuse element.

[0008]

With the above construction, it is possible to provide a fuse resistor having a structure in which a resistor and a fuse element are independent of each other, and a manufacturing method thereof. For example, with the above configuration, the fusing power value can be set by the length and width of the fuse element, the resistance value can be adjusted regardless of the fusing power value of the fuse element, and the surge resistance is deteriorated. It is possible to provide a fuse resistor and a method for manufacturing the same that can lower the fusing power without the need.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A square chip fuse resistor according to an embodiment of the present invention will be described in detail below with reference to the drawings. 1 to 6 are views for explaining a square chip fuse resistor according to an embodiment of the present invention, FIG. 1 is a diagram showing an example of a resistor formation state of the resistor, and FIG. 2 is a diagram of the resistor. FIG. 5 is a diagram showing an example of a fusing element forming state, FIG. 3 is a diagram showing an example of an electrode forming state and a trimming state of the resistor, FIG. 4 is a diagram showing an example of a heat storage layer forming state of the resistor, and FIG. Is a perspective view showing an example of a completed state of the resistor, and FIG. 6 is AA of FIG.
FIG.

It should be noted that in the drawings showing the respective states, some of them are schematically represented so that the formation state of each part is clear and the formation state of each part is easily recognizable. That is, in the drawings showing the respective states, the lower state is expressed in an identifiable manner even in an opaque portion. In the figure,
Reference numeral 10 denotes a substrate, which is an electrically insulating ceramic substrate having a substantially rectangular predetermined thickness, such as an alumina substrate of a sintered body of 96% alumina. In this example,
The substrate 10 is not limited to a fired alumina substrate, and may be fired together with a thick film resistor, which will be described later, using a green sheet of alumina or the like, for example.

Reference numeral 30 designates a resistor, which is a thick film resistor formed by screen printing or a thin film resistor formed by sputtering, vacuum deposition, plating or the like, which is biased in the longitudinal direction of one surface of the substrate 10 and has a substantially rectangular shape. Form to thickness. In addition,
As a material for the thick film resistor, a thick film paste such as ruthenium oxide is used, and as a material for the thin film resistor, nickel-
Alloys such as chrome, nickel-phosphorus, nickel-phosphorus-tungsten alloys are used.

Reference numeral 31 is a fusing element, which is a portion which is blown when an excessive current flows. The housing element 31 has one end formed on the resistor 30 and the other end formed in the vicinity of the end portion in the longitudinal direction of the substrate 10, and has a substantially U shape so that the housing element 31 has a predetermined width and a predetermined length. Make a bent shape. The shape of the fuse element is not limited to the substantially U shape, and may be, for example, a W shape, a crank shape, a linear shape, or the like, which is suitable for forming a predetermined length. You can do this. Further, even if the housing element 31 is formed as a thick film by screen printing or direct drawing, spattering, vacuum deposition,
A thin film of aluminum or the like may be formed by plating.

Reference numerals 20 and 21 denote electrodes, which are located near both short sides of the resistor forming surface (hereinafter referred to as "top surface") of the substrate 10 and pass through the end face of the substrate 10 which is in contact with the short side on which the electrodes are formed. The non-formed surface (hereinafter referred to as the “lower surface”) is formed so as to extend in the vicinity of both short sides of the non-formed surface so that its cross section has a substantially U-shape. The electrode 20 is formed in a substantially rectangular shape so as to cover the vicinity of the end of the fusing element 31 within a predetermined range from the vicinity of the short side of the substrate 10 to the end of the fusing element 31. The method of forming the electrodes 20 and 21 is well known, and thus a detailed description thereof will be omitted. However, a thick film paste of silver-palladium, silver, copper, or the like is formed by screen printing, or chrome, nickel, or copper is used. A metal material such as is formed by a method such as sputtering, vacuum deposition, and plating.

Cuts 30a and 30b are formed by trimming for adjusting the resistance value. In the figure, an example in which two straight cuts are cut is shown, but the present embodiment is not limited to this. For example, an L-shaped cut or one straight cut may be used. . Reference numeral 41 denotes a heat storage layer, which prevents the heat generated in the fusing element 31 from being dissipated, and is covered by screen printing or the like so as to substantially cover the fusing element 31 and is low in electrical insulation and low in thermal conductivity. It is a melting point glass paste or the like coated in a substantially rectangular shape.

Reference numeral 40 denotes an insulating film, which is a resistor 30, an electrode 20,
An electrically insulating glass paste, an epoxy resin, or the like is overcoated by screen printing or the like so as to substantially cover the upper surface portion of 21, the heat storage layer 41, and the like. After that, the square chip fuse resistor is in a completed state, an example of which is shown in FIGS.

FIG. 7 is a flow chart showing an example of a manufacturing process of a square chip fuse resistor. Note that the following description is not limited to the case where one square chip fuse resistor is manufactured, and can be applied, for example, to the case where a plurality of square chip fuse resistors are simultaneously manufactured, and the square chip fuse resistor is used in the final step. You can separate them into individual vessels.

First, in step P1 shown in FIG. 7, a substrate manufacturing process for forming the substrate 10 in a predetermined size is performed to manufacture a substantially rectangular substrate 10 having a predetermined manufacturing unit size. It should be noted that the unit has an arbitrary size, and may be manufactured for each one square chip fuse resistor, for example, several tens of them may be manufactured at the same time, and may be manufactured according to each case. Further, the state diagrams of the respective steps described below show only one single chip, but the same applies to the case where a plurality of chips are simultaneously formed.

Subsequently, in step P2, a resistor 30 of which an example is shown in FIG. 1 is formed on the upper surface of the substrate 10 by a method such as screen printing or spattering. Then, the process P3
Then, the fusing element 31 whose example is shown in FIG. 2 is formed on the upper surface of the substrate 10 by a method such as screen printing or spattering. Subsequently, in step P4, the electrodes 20 and 21 of which an example is shown in FIG. 3 are formed on the substrate 10 by a method such as screen printing or spattering. The step P4 is, for example, a step of forming an electrode portion on the upper surface of the substrate 10, a step of forming an electrode portion on the lower surface of the substrate 10, and then a conductor portion on the end surface of the substrate 10 to form electrodes on the upper and lower surfaces. And the step of electrically connecting.

Then, in step P5, the resistance value is trimmed as necessary. In the resistance value trimming, the resistance value is adjusted by making a cut in the pattern of the resistor 30 with a laser beam or sandblasting.
Then, in step P6, the heat storage layer 41, an example of which is shown in FIG. 4, is formed by a method such as screen printing so as to substantially cover the fusing element 31.

Then, in step P7, the insulating film 40 is overcoated by screen printing or the like so as to substantially cover the resistor 30, the upper surfaces of the electrodes 20 and 21, the heat storage layer 41 and the like. Subsequently, in step P8, the rated resistance value, the product number, etc. are marked by, for example, imprinting on the insulating film 40.

Subsequently, in step P9, a portion of the electrodes 20 and 21 which is not covered with the insulating film 40, mainly the electrode portion of the end surface or the lower surface of the substrate 10, is plated with nickel or the like, and then soldered. Apply processing. And finally, the process P1
At 0, an inspection is performed to complete the square chip fuse resistor.

After the step P9 or the step P10 is completed, dicing is performed as required to separately form a square chip fuse resistor for each chip. For example, when a plurality of square chip fuse resistors are manufactured at the same time, the chips are separated and molded, and when they are manufactured for each chip, the peripheral part is shaped. Although omitted in the above description, the step of forming the thick film includes, for example, a baking step of baking the thick film paste at 850 ° C. for 10 minutes after printing the thick film paste. A predetermined pattern is formed with a mask, or a resist film is formed after forming a thin film,
A step of etching the formed thin film is included.

In the steps P2 to P4, the resistor 3
0, the housing element 31, the electrodes 20, 21 are
The electrodes 20 and 21 may be collectively fired after printing without being fired in each of the steps P2 to P4. Further, for example, the resistor 30 and the fusing element 31 are partially burned. You may bake collectively. Further, in steps P6 and P7, the heat storage layer 41 and the insulating film 40 may not be baked in the respective forming steps of steps P6 and P7, but may be baked together after the insulating film 40 is printed.

In the square chip fuse resistor of the present embodiment having the above-mentioned structure, since the resistor 30 and the husing element 31 have an independent structure, the length and width of the husing element 31 etc. Thus, the fusing power value can be set. Therefore, in the present embodiment, the resistance value can be adjusted by trimming the resistor 30 irrespective of the fusing power value of the fusing element 31, so that the square chip fuse resistor of the present embodiment is A wide resistance value range of about 0.1 [Ω] to about 600 [Ω] can be obtained.

Further, in this embodiment, since the fusing element 31 is formed by screen printing or spattering, the cross-sectional area of the current path of the fusing element 31 becomes substantially uniform, and the pattern of the fusing element 31 is formed. Even if the width is narrowed and the fusing power is reduced, sufficient surge resistance can be obtained. Therefore, for example, in the case of the fuse fuse of the present embodiment in which the fusing current is 2 [A], the fusing power can be reduced to about 0.8 [W].

As described above, according to this embodiment,
Since the resistor and the fusing element are made independent, the fusing power value can be set by the length and width of the fusing element. Therefore, in the present embodiment, the resistance value can be adjusted regardless of the fusing power value of the fusing element, and a wide resistance value range can be obtained.

Further, in the present embodiment, the cross-sectional area of the current path of the fusing element is substantially uniform, and the pattern width of the fusing element is narrowed to reduce the fusing power, thereby improving the resistance. For example, in the case of the fuse resistor of the present embodiment having a fusing current of 2 [A], the fusing power can be reduced to about 0.8 [W] without deteriorating the surge property.

[0028]

As described above, according to the present invention, it is possible to provide a fuse resistor having a structure in which a resistor and a fuse element are independent of each other, and a manufacturing method thereof. For example, according to the present invention, the fusing power value can be set according to the length, width, etc. of the fuse element, and the resistance value can be adjusted regardless of the fusing power value of the fuse element, without deteriorating the surge resistance. It is possible to provide a fuse fuse capable of reducing the fusing power and a manufacturing method thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a resistance body formation state of a square chip fuse resistor according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a fusing element formation state of the present embodiment.

FIG. 3 is a diagram showing an example of an electrode formation state and a trimming state of the present embodiment.

FIG. 4 is a diagram showing an example of a heat storage layer forming state of the present embodiment.

FIG. 5 is a perspective view showing an example of a completed state of the present embodiment.

6 is a sectional view taken along the line AA of FIG.

FIG. 7 is a flow chart showing an example of a manufacturing process of this example.

FIG. 8 is a diagram showing a structure of a conventional square chip fuse resistor.

[Explanation of symbols]

 10 Substrate 20,21 Electrode 30 Resistor 31 Fusing Element 40 Insulating Film 41 Heat Storage Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H01C 17/06 A 8834-5E H01H 69/02 7250-5G

Claims (4)

[Claims] 1. A fuse resistor formed on an insulating substrate of a predetermined size, the resistor layer having a predetermined size formed on one surface of the insulating substrate, and one end of the resistor layer near one end of the resistor layer. A fuse element of a predetermined size formed so as to overlap in the vicinity of a portion, at least one first electrode portion formed so as to overlap near the other end of the resistor layer, and near the other end of the fuse element And a heat storage layer formed so as to substantially cover the fuse element, the fuse resistor comprising at least one second electrode portion formed so as to overlap with the fuse element. 2. The insulating substrate is an alumina substrate, the resistor layer is a thick film resistor, the electrode portion is a thick film conductor, and the heat storage layer is made of glass. The fuse resistor according to claim 1. 3. The insulating substrate is an alumina substrate, the resistor layer is a thin film resistor, the electrode portion is a thin film conductor, and the heat storage layer is made of glass. The fuse resistor according to 1. 4. A resistor forming step of forming a resistor layer of a predetermined size on one surface of an insulating substrate of a predetermined size, and a predetermined size so that the resistor layer overlaps with one end portion in the vicinity of the one end portion. And a step of forming a fuse element, wherein at least one first electrode portion is formed so as to overlap in the vicinity of the other end portion of the resistor layer, and is overlapped in the vicinity of the other end portion of the fuse element. And a heat storage layer forming step of forming a heat storage layer so as to substantially cover the fuse element, and a heat storage layer manufacturing method.