KR101050243B1 - Chip fuse and manufacturing method - Google Patents

Abstract

There is provided a chip fuse capable of preventing the melting time at high magnification from being shortened with respect to the rated current, and shortening the melting time at low magnification with respect to the rated current. The chip fuse 10 is formed such that the first heat storage layer 12 made of a low thermal conductivity film material is formed on the insulating substrate 11, and does not contact the insulating substrate 11 on the first heat storage layer 12. A fuse film 13 is formed, and the fuse film 13 has a fuse element portion 13b between the surface electrode portions 13a disposed at both ends, and a film having low thermal conductivity on the fuse element portion 13b. The second heat storage layer 15 made of a material is formed, and the first heat storage layer 12 is formed thicker than the second heat storage layer 15. The first heat storage layer 12 and the second heat storage layer 15 are formed of a sheet-like material in a B stage state containing a photosensitive device.

Thermal conductivity, heat storage layer, insulation substrate, fuse film, surface electrode part, fuse element part, chip fuse, photosensitive member, sheet material

Description

Chip fuse and manufacturing method {CHIP FUSE AND CHIP FUSE MANUFACTURING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip fuse and a method of manufacturing the same, and more particularly, to a chip fuse in which an upper layer and a lower layer of a fuse element portion are formed by a low thermal conductive film.

As a technique already disclosed regarding a chip fuse, there exist some described in patent document 1. As shown in FIG. This relates to a chip fuse in which a silicon resin film is formed on an upper surface of an inorganic substrate, a fuse film is formed on the silicon resin film, and a protective film is formed on the fuse film by a silicone resin. As thickness, 10 micrometers is illustrated.

In Patent Document 1, a silicone resin is used to prevent melting and ignition of solder in a connection portion with a printed wiring board. However, even when the material and the heat transfer area of the fuse element are changed, the degree of freedom of the blowdown characteristic is limited. The task is left.

In addition to this, Patent Document 2 relating to a method for manufacturing a chip fuse describes that the temperature rise until melting is determined by the balance between the heat generation amount of the fuse element and the heat dissipation amount to the peripheral member, and the melting time is determined. It is. The factors influencing the melt time are the resistance value, the heat transfer area and the heat transfer rate, the resistance value is a factor for the calorific value, and the heat transfer area and the heat transfer rate are factors for the heat dissipation rate. In order to increase, the effect that these factors need to examine is described.

However, in this patent document 2, the material and heat transfer area of the member around the fuse element have not been examined in detail, and no means or method for controlling the amount of heat radiation from the fuse element to the surrounding member is disclosed.

Patent Document 1: Japanese Patent Application Laid-Open No. 11-96886

Patent Document 2: Japanese Patent Application Laid-Open No. 9-320445

(Initiation of invention)

(Tasks to be solved by the invention)

SUMMARY OF THE INVENTION The present invention solves the above problems, and its object is not to limit the degree of freedom of melting characteristics, to prevent shortening of the melting time at high magnification with respect to the rated current, and to reduce the melting time at low magnification with respect to the rated current. The present invention provides a chip fuse and a method of manufacturing the same.

Moreover, this invention provides the manufacturing method of the chip fuse which can form the chip fuse as mentioned above with precision and comparatively easy.

(Means to solve the task)

In this invention, the said subject is solved by the means of (1)-(3) described below.

(1) A first heat storage layer made of a film material having low thermal conductivity is formed on an insulating substrate, and a fuse film is formed so as not to contact the insulating substrate on the first heat storage layer, and the fuse film is disposed at both ends thereof. And a fuse element portion between the portions, wherein a second heat storage layer made of a low thermal conductivity film material is formed on the fuse element portion, and the first heat storage layer is formed thicker than the second heat storage layer.

(2) The chip according to the above (1), wherein the first heat storage layer and the second heat storage layer made of a film material having low thermal conductivity are formed from a sheet-like material in a B stage state (semi-cured state) containing a photosensitive device. fuse.

(3) A first heat storage layer is formed on the insulating substrate, a fuse film is formed on the first heat storage layer, and the fuse film has a fuse element portion between the surface electrode portions disposed at both ends, and a second heat storage on the fuse element portion. A method of manufacturing a chip fuse in which a layer is formed, wherein a first heat storage layer is formed by stacking a predetermined number of sheet-like materials in a B-stage state (semi-cured state) containing a photosensitive device and having a substantially uniform thickness on an insulating substrate. Forming a fuse element between the surface electrode portion and forming a fuse film on the first heat storage layer so as not to contact the insulating substrate; and a sheet-like material in the same B stage state used for the first heat storage layer. Forming a second heat storage layer by overlapping a predetermined number of surfaces between both surface electrode portions, and in the step of forming the first heat storage layer, the step of forming the second heat storage layer The manufacturing method of the chip fuse characterized by increasing the number of sheets of sheet-like material in the B-stage state.

In the present invention, the film material having low thermal conductivity constituting the first heat storage layer and the second heat storage layer is preferably a film material having a thermal conductivity of about 0.1 to 0.4 W / m ° C. For example, an acrylate resin and an epoxy It is possible to form using the sheet-like material containing resin materials, such as resin, and a photosensitive device.

(Effects of the Invention)

In the chip fuse of the present invention, since a heat storage layer made of a film material having low thermal conductivity is provided above and below the fuse film, and a lower heat storage layer is formed thicker than the heat storage layer of the upper layer, the degree of freedom of melting characteristics is not limited. It is possible to prevent the melting time at high magnification from being shortened with respect to the rated current and to shorten the melting time at low magnification with respect to the rated current.

That is, when the temperature of the fuse element portion rises while the chip fuse is energized, the heat is transferred downward to accumulate in the first heat storage layer, while the heat transferred upward is accumulated in the second heat storage layer. In general, since the insulating substrate has a higher thermal conductivity than air, the first heat accumulating layer is formed thicker than the second heat accumulating layer, thereby suppressing heat escaping downward from the first heat accumulating layer through the insulating substrate. At low magnification with less calories, it is possible to shorten the melting time by trapping heat. In addition, the second heat storage layer formed relatively thinner than the first heat storage layer makes it possible to prevent heat from shortening by releasing heat at a high magnification with a large amount of heat.

In the method for manufacturing a chip fuse of the present invention, a first heat storage layer is formed by stacking a predetermined number of sheet-like materials in a B-stage state formed on a substantially uniform thickness on an insulating substrate, and provided on the first heat storage layer. A second heat storage layer is formed on the fuse film by stacking a predetermined number of sheet-like materials in the same B stage state. Since these sheet-like materials are rich in uniformity, by adjusting the number of sheets to overlap, the first and second heat storage layers can be formed with a desired thickness with high accuracy and relatively easily.

1A to 1D are plan views illustrating a manufacturing process of a chip fuse.

2 (e) to 2 (h) are plan views illustrating a manufacturing process following FIG. 1.

(A) is sectional drawing along the A-A line of FIG. 2, (b) is sectional drawing along the B-B line of FIG.

4 is a graph comparing the melting characteristics of the chip fuse and the conventional example of the present invention.

FIG. 5 is an enlarged graph of the low magnification range in FIG. 4.

6 is an enlarged graph illustrating the high magnification range in FIG. 4.

(Explanation of the sign)

10 chip fuse 11 sets insulated board

12 First heat storage layer 13 fuse film

13a surface electrode part 13b fuse element part

14 Melting edge 15 Second heat storage layer

(The best mode for carrying out the invention)

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described with reference to drawings, this invention is not limited to this.

1 (a)-(d) and 2 (e)-(h) are plan views showing the process of manufacturing the chip fuse 10 of the present invention, and FIG. 3 (a) is a plan view of FIG. 2 (h). AA line and FIG. 3 (b) are sectional drawing of the chip fuse 10 in the BB line of FIG. 2 (h).

In the chip fuse 10, a first heat storage layer 12 made of a film material having low thermal conductivity is formed on an insulating substrate 11, and a fuse film 13 is provided on the first heat storage layer 12. The fuse film 13 has a surface electrode portion 13a disposed at both ends and a fuse element portion 13b formed in a relatively narrow width so as to connect the surface electrode portions 13a at both ends thereof, and the surface electrode portion 13a. Ni and a Sn plated film or Sn plated film are formed on a part of and the entire surface of the fuse element portion 13b, and the plated film becomes the melted end portion 14. In addition, on the melted portion 14, a second heat storage layer 15 made of a film material having low thermal conductivity is provided in a region slightly wider than the melted portion 14, and a protective layer (2) is provided on the second heat storage layer 15. 16 is formed, the back electrode 17 is provided at both ends of the back surface side of the insulating substrate 11, the end face electrode 18 is provided at both end surfaces of the insulating substrate 11, and the electrode plating film 19 The front electrode 13a, the end face electrode 18, and the back electrode 17 are provided to cover.

Here, an alumina substrate is used as the insulating substrate 11, and the low thermal conductivity film material constituting the first heat storage layer 12 and the second heat storage layer 15 has a thermal conductivity of 0.1 to 0.4 W / m 占 폚. It is preferable that it is a film material of the grade, for example, predetermined number of sheet-like materials of B stage state (semi-cured state) of about 30 micrometers in thickness containing resin materials, such as an acrylate resin and an epoxy resin, and a photosensitive member, respectively Can be used. For example, when the 1st heat storage layer 12 overlaps two sheets of sheet-like material of the above-mentioned B stage state, and the 2nd heat storage layer 15 is formed using one sheet-like material of the same B stage state, The first heat storage layer 12 can be formed thicker than the second heat storage layer 15. The hardening of the sheet-like material of the B stage state containing this resin material, such as an acrylate resin and an epoxy resin, and a photosensitive device, is excellent in chemical-resistance with respect to etching liquid, and low thermal conductivity.

The first heat storage layer 12 covers almost the entire surface of the insulating substrate 11 except for predetermined portions of the primary division grooves 11a and the secondary division grooves 11b of the insulating substrate 11. The removal part 12a from which the first heat storage layer 12 is removed has a shape and arrangement as shown in FIGS. 1B and 1C, that is, the primary division groove 11a and the secondary division groove ( It is formed in an elongate range over a predetermined length of 11b). The fuse film 13 is laminated on the first heat storage layer 12 in a shape as shown in FIG. 1 (d) so as not to contact the insulating substrate 11.

As described above, the first heat storage layer 12 is formed thicker (depth) than the second heat storage layer 15, for example, almost twice as thick, so that the degree of freedom of the melting characteristic is not limited, and the rated current is not limited. It is possible to prevent the melting time at high magnification from being shortened and to shorten the melting time at low magnification with respect to the rated current.

Next, the manufacturing method of the chip fuse 10 of rated current 1A is demonstrated with reference to FIG. As an integrated insulating substrate for manufacturing a chip fuse, an alumina substrate having a purity of about 96% is used. The chip fuse 10 is formed by forming each structure over a plurality of layers on the integrated insulating substrate and cutting them in the longitudinal direction and the horizontal direction. In FIG. 1 (c), (d) and FIGS. 2 (e) to (h) show a plan view of one compartment on the integrated insulating substrate, that is, a compartment which becomes one chip fuse.

[Home installation process of integrated insulation board]

First, the primary dividing groove 11a and the secondary dividing groove 11b for cutting are provided in the collective insulating substrate 11 by means of a laser or the like. The primary insulating groove 11a and secondary secondary groove 11b are formed in advance in the collective insulating substrate, and in the case of using the collective insulating substrate, the step of installing the grooves is omitted.

[Formation process of first heat storage layer]

In order to form the first heat storage layer 12, a predetermined number of sheet-like materials are attached onto the collective insulating substrate 11. The sheet-like material includes a resin material such as an acrylate resin and an epoxy resin and a photosensitive device, and uses a B-stage state formed at a thickness of about 30 μm. In the sticking step, one sheet of sheet-like material in the B-stage state is stuck on the collective insulating substrate 11, heated to a predetermined temperature, and pressurized at a predetermined pressure, and further, one sheet-like material is placed thereon. Similarly, pressurize and ladle while heating. The two sheets of sheet-like material heated and pressed are about 56 mu m in thickness after adhesion. In this way, the thickness of the first heat storage layer 12 can be adjusted with high accuracy by wrapping only a predetermined number of sheet-like materials in the B stage state.

Next, after exposing to ultraviolet-ray 500mJ / cm <^2> through a photomask on a sheet-like material, it is immersed in 1 wt% of sodium carbonate solutions for several minutes, and the sheet-like material is formed in the shape shown to FIG. 1 (b), (c). do. As a result, the first heat storage layer 12 from which the removal portion 12a is removed is formed on the insulating substrate 11.

By using a photosensitive device as the sheet-like material and carrying out the above-described steps, the dimensional accuracy of the planar shape of the first heat storage layer 12 can be increased, and the variation in melt characteristics can be reduced.

[Fuse Film Formation Step]

An electrolytic copper foil or a rolled copper foil having a thickness of about 3 μm is affixed on the collective insulating substrate 11 on which the first heat storage layer 12 is formed. This pasting step is performed by applying a predetermined pressure at a temperature higher than normal temperature for a predetermined time. Next, a negative type dry film is pasted on an electrolytic copper foil, or a liquid resist is apply | coated, and it exposes through a photomask from above, an electrolytic copper foil is etched and a dry film or a liquid resist is peeled off. . By the above process, the fuse film 13 is formed in planar shape as shown to Fig.1 (d).

[Formation process of fuse film melt end]

Ni and Sn plating films or Sn plating films are provided on the front surface of the fuse element portion 13b in the fuse film 13 and a part of the surface electrode portions 13a continuous on both sides thereof by an electroplating method. The blowout portion 14 as shown in FIG. 2 (e) is formed, whereby the fuse film 13 is subjected to the M effect to obtain blow-off characteristics.

[Formation process of second heat storage layer]

Next, as shown in FIG. 2 (f), the second heat storage layer 15 is formed in a range covering all of the melted portions 14. The second heat storage layer 15 also uses a sheet-like material in a B-stage state formed with a thickness of about 30 μm, similar to that of the first heat storage layer 12, and one sheet of this sheet-like material is used throughout the collective insulating substrate 11. It affixes on and adheres by predetermined pressure, heating to predetermined temperature. This one sheet-like material is about 25 micrometers in thickness after adhesion | attachment. The bonded sheet-like material is exposed to ultraviolet rays through a photomask, and then immersed in a sodium carbonate solution for several minutes, and formed into the shape shown in Fig. 1G.

[Formation process of protective layer]

Next, the protective layer 16 is formed in a slightly wider range so as to cover all of the second heat storage layers 15. The protective layer 16 is a film | membrane formed from an epoxy resin material by screen printing, and this improves concealment and mechanical strength.

[Formation process of backside electrode, end face electrode, etc.]

After the protective layer 16 is formed, a silver paste is applied to the back surface side of the collective insulating substrate 11 by screen printing and heat-bonded to form the back electrode 17. Next, the integrated insulating substrate is cut along the primary dividing groove 11a to form an insulating substrate having a narrow and long shape, and a silver paste is applied and heat-bonded to the long side of the narrow and long insulating substrate, Alternatively, the cross section electrode 18 is formed by forming a Cr film and a Ni film by the sputtering method. Further, the narrow and long insulating substrate is cut along the secondary dividing groove 11b to form a single chip, and the electrode plating film 19 made of a Cu film, a Ni film, and a Sn film by a barrel plating method. In this case, the chip fuse 10 of the present invention is completed as shown in Figs. 2 (h) and 3.

Next, FIG. 4 is a graph comparing the melting characteristics of the chip fuse of the rated current 1A according to the embodiment of the present invention and the chip fuse of the comparative example. 5 is an enlarged graph of a range in which the rated current ratio is low in FIG. 4, and FIG. 6 is an enlarged graph of a range in which the rated current ratio is high in FIG. 4.

Here, Sample C is one embodiment of the present invention, wherein the first heat storage layer is formed to be approximately 60 µm, and the second heat storage layer is formed to be approximately 30 µm.

On the other hand, the chip fuses of samples A, B, and D are comparative examples, and the relationship between the relative thicknesses of the first heat storage layer and the second heat storage layer is different from that of the chip fuse according to the present invention. Is formed in the same manner as the chip fuse of the present invention. Sample A is formed with a first heat storage layer of approximately 30 μm and a second heat storage layer of approximately 30 μm. Sample B is formed with a first heat storage layer of approximately 30 μm and a second heat storage layer of approximately 60 μm. Sample D is formed with a first heat storage layer of about 60 μm and a second heat storage layer of about 60 μm.

When the sample C which is one embodiment of the present invention and the sample D (the first heat storage layer has the same thickness as the sample C) are compared, in the range where the rated current ratio is low, the sample C is the sample D as shown in FIG. 5. Melting time is shorter than that. On the other hand, in the range where the rated current ratio is high, as shown in Fig. 6, the melting time of the sample C is longer than that of the sample D. From this, it is understood that the chip fuse of the present invention can shorten the melting time at high magnification with respect to the rated current, and shorten the melting time at low magnification with respect to the rated current.

Claims (3)

A first heat storage layer made of a low thermal conductivity film material is formed on the insulating substrate, and a fuse film is formed on the first heat storage layer so as not to contact the insulating substrate, and the fuse film is disposed between the surface electrode portions disposed at both ends. A film having a fuse element portion, wherein a second heat storage layer made of a film material having low thermal conductivity is formed on the fuse element portion, the first heat storage layer is formed thicker than the second heat storage layer, and the film having low thermal conductivity. And the first heat storage layer and the second heat storage layer made of a material are formed of a sheet-like material in a B stage state containing a photosensitive device. A first heat storage layer is formed on the insulating substrate, a fuse film is formed on the first heat storage layer, and the fuse film has a fuse element portion between the surface electrode portions disposed at both ends, and a second heat storage layer is formed on the fuse element portion. As a method of manufacturing a chip fuse, Forming a first heat storage layer by stacking a predetermined number of sheet-like materials in a B-stage state containing a photosensitive member having a uniform thickness on an insulating substrate, and forming a fuse film on the first heat storage layer so as not to contact the insulating substrate. In addition, a step of forming a fuse element portion between the surface electrode portion, and a predetermined number of sheets of sheet-like material in the same B-stage state used for the first heat storage layer are overlapped between both surface electrode portions to form a second heat storage layer. Including the process, In the formation process of a said 1st heat storage layer, the number of sheets of sheet-like material of an overlapping B stage state is made larger than the formation process of a said 2nd heat storage layer, The manufacturing method of the chip fuse characterized by the above-mentioned. delete

Images