JP2000021612A - Manufacture of current protecting chip element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve insulation resistance after fusing and reliability, by forming connection wirings with electrodes positioning current protecting elements, on the parts of holes for gap formation where unnecessary parts of a metal foil thinned to be a specified thickness are eliminated, and performing cutting at the parts of holes between adjacent current protecting elements. SOLUTION: A very thin copper foil or a very thin copper foil with aluminum carrier is used for a metal foil of 3-9 μm in thickness. Two insulating plates 11, 12 formed by etching and eliminating copper foils of both surfaces of a laminated plate stuck on both surfaces of the metal foil are made first and second insulating layers. Two insulating plates 101, 102 with resin films are formed, and holes 4 for gap formation are made. A board on which current protecting elements 8 and connection wirings 71 are formed, the insulating plate 102 with resin film, a resin film 3 where holes are made in parts of the holes 4 for gap formation and a copper foil 72 of 18 μm in thickness are stuck on the single surface. Thus laminated plates 111, 112 are formed. The laminated plates 111, 112 where two copper foils 72 are arranged on the upper sides and the lower sides are so laminated in order while the holes 4 are aligned with parts of the elements 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for manufacturing a chip-type current protection device.

[0002]

2. Description of the Related Art A current protection element is used for overcurrent protection of electronic equipment. The current protection element according to the present invention is connected to an electric circuit in series, and when an overcurrent flows, the wiring in the protection element is cut, and the current after that is cut off, thereby protecting the device. .

[0003] Such elements are commonly referred to as:
It is called a fuse, but to say a fuse,
It is necessary to satisfy the characteristics specified in various standards. However, with the diversification of electronic devices, current protection elements having characteristics different from those of conventional fuse standards have appeared. The present invention
The present invention relates to a current protection element (current protector) performing the above-described operation mechanism including a fuse.

In the overcurrent protection device, an electronic switch using a thyristor or a transistor can be used in addition to the above current protection element. However, in such a case, since the number of circuit components increases and the power consumed by the protection circuit also increases, miniaturization and low power consumption are required as in a portable device operated by a battery. It was not necessarily suitable for certain applications.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 60-143544, silver or silver-palladium is formed on a ceramic substrate as a first layer, a nickel layer is formed on a second layer, and solder or tin is formed on a third layer. It is known that three conductive layers are formed to improve the fusing characteristics at the time of soldering, and that the surface of the conductive layer is coated with a nonflammable (flame retardant) resin such as a silicone resin is also disclosed.

In Japanese Utility Model Publication No. 55-2565,
There is disclosed a method of forming an electrode of a chip-type resistance element, in which a fuse element is provided on a ceramic base and a recess is provided on the fuse element.

Japanese Patent Application Laid-Open No. Hei 8-96694 discloses an example in which a ceramic base such as alumina having concave portions above and below a fuse element made of a thin metal wire is arranged.

[0008]

However, when a ceramic substrate is provided with a current protection element (fuse), the thermal resistance of the ceramic substrate is small.
As disclosed in JP-A-143544, even if the current protection element is covered with a nonflammable (flame retardant) resin,
There is a problem that the heat dissipation is high and the current value to be melted varies depending on the ambient temperature.

In the method of forming electrodes of a chip-type resistor element disclosed in Japanese Utility Model Publication No. 55-2565, a fuse element is provided on a ceramic base and a concave portion is provided on the fuse element. The thermal resistance of the ceramic substrate thus formed is low, and the temperature of the outer surface of the fuse element excessively rises due to the heat generated at the time of fusing, and the fusing residue remains on the ceramic substrate at the time of fusing. Further, there is a problem that the current value to be blown increases when the resistance value is constant, and the fuse resistance increases when the fusing current is constant.

[0010] Even when a ceramic base made of alumina or the like having concave portions above and below a fuse element made of a thin metal wire, which is disclosed in Japanese Patent Application Laid-Open No. 8-96694, heat generated during fusing similarly causes the outer surface of the fuse element to be heated. There is a problem that if the temperature rises excessively or the resistance value is constant, the current value for fusing increases, and if the fusing current is constant, the fuse resistance increases.

In order to solve the problem of the chip fuse of the ceramic base, it is conceivable to use an insulating substrate made of an organic resin. However, when the resin of the substrate is an epoxy resin, a phenol resin, a polyimide resin, or the like, smoke or combustion occurs. There was a problem.

The present invention is excellent in forming accuracy (thickness and width of wiring) of a current protection element, is excellent in suppressing heat radiation, suppressing smoke and ignition, and has high insulation resistance after fusing and high reliability. It is an object of the present invention to provide a chip-type current protection element and a method of manufacturing the same.

[0013]

SUMMARY OF THE INVENTION A method of manufacturing a chip-type current protection device according to the present invention comprises the steps of: a. A first insulating layer having two holes for forming voids and a second insulating layer;
Fabricating the insulating layer of b., B. Laminating and bonding the metal foil to the first insulating layer; c. Thinning the metal foil to a thickness of 3-9 μm, d. Forming a plurality of current protection elements, electrodes, and connection wiring between the electrodes and the current protection element such that the unnecessary parts of the metal foil are removed by etching so that the current protection elements are located at the positions of the holes for forming voids; e. . A second insulating layer in which a hole for forming a gap is aligned with the position of the current protection element, and a first insulating layer and an outer side of the second insulating layer,
A step of laminating a third insulating layer having a metal foil bonded to only one side thereof with an adhesive layer so that the metal layer is on the outside, and laminating and bonding; f. Making a hole for an electrode at a location of the connection wiring of the laminated and bonded object; g. Plating and electrically connecting the connection wiring and the metal foil; h. Forming an electrode by etching away portions other than the electrode, i. A step of cutting into individual chip-type current protection elements in which electrodes at both ends are formed by cutting between adjacent current protection elements and at holes.

Also, a. A first insulating layer having two holes for forming voids and a second insulating layer;
Fabricating the insulating layer of b., B. Laminating and bonding the metal foil to the first insulating layer; c1. 3 to 9 places other than the place to be the connection wiring of the metal foil
thinning to a thickness of μm, d. Forming a plurality of current protection elements, electrodes, and connection wiring between the electrodes and the current protection element such that the unnecessary parts of the metal foil are removed by etching so that the current protection elements are located at the positions of the holes for forming voids; e. . A second insulating layer in which a hole for forming a gap is aligned with a position of the current protection element, and a first insulating layer and an outer side of the second insulating layer,
A step of stacking and laminating a third insulating layer in which a metal foil is stuck on only one side of the two sheets via an adhesive layer such that the metal layer is on the outside, f. Making a hole for an electrode at a location of the connection wiring of the laminated and bonded object; g. Plating and electrically connecting the connection wiring and the metal foil; h. Forming an electrode by etching away portions other than the electrode, i. A step of cutting into individual chip-type current protection elements having electrodes formed at both ends by cutting between adjacent current protection elements and at holes.

[0015] The metal foil is a metal foil with a carrier,
A first copper layer having a thickness in the range of 10 to 50 μm;
A composite metal foil having a second copper layer having a thickness of m and a nickel or alloy layer thereof having a thickness of 1 μm or less as an intermediate layer between the two copper layers can be used.

After the carrier is removed, a step of pre-plating the metal foil having a thickness of 3 to 9 μm so that the thickness of the connection wiring is 10 to 50 μm may be provided.

A resin having a resin flow of 200 μm or less can be used for the adhesive layer for bonding the third insulating layer to the first insulating layer and the second insulating layer.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the thickness of the current protection element is set to 3 to 9 .mu.m if it is less than 3 .mu.m, it is difficult to control the thickness accuracy, and it is difficult to avoid pinholes. This is because, if it exceeds, it becomes difficult to form a current protection element wiring for accurately performing fusing when overcurrent is applied.

The thickness of the connection wiring at the connection between the current protection element and the electrode is preferably in the range of 10 to 50 μm because of the environmental temperature change at the place where the current protection element is installed,
Thermal stress due to temperature change due to on / off of the current flowing through the element itself tends to concentrate on the point where the current protection element and the electrode are connected.
If the thickness is too thick, the burden on the production (increase of working time, increase of materials, change of lamination bonding conditions due to deterioration of embedding by resin material, etc.) increases, and if the thickness exceeds a certain level, the thickness increases. This is because the degree of improvement of the effect is reduced.

(Step a) It is desirable to use a substrate made of a resin and a reinforcing material for the first insulating layer and the second insulating layer of the present invention, and the resin may be an epoxy resin, a phenol resin, or a polyimide. A resin or the like can be used, and a reinforcing material selected from glass cloth and glass paper can be used.

To form a hole for forming a gap in the first insulating layer and the second insulating layer, a drill machine generally used for drilling a through hole or the like in a wiring board can be used.

(Step b) In order to thin the metal foil to a thickness of 3 to 9 μm, a method in which a thicker metal foil is attached and then removed by etching, and a method in which a thin metal foil is bonded to a carrier are used. And then removing the carrier. The reason for this is that a thick metal foil or a thin metal foil bonded to a carrier has high workability and does not cause breakage or wrinkles, so that a circuit can be formed accurately.

When a thick metal foil is used, the thickness of the metal foil is 15 μm from the viewpoint of handleability during lamination and wiring formability.
m to 70 μm, more preferably 1 to 70 μm.
It is preferably in the range of 8 μm to 35 μm. When the thickness of the metal foil is less than 15 μm, when laminating and adhering to the first insulating layer in the previous period, irregularities may be generated on the surface of the metal foil in the portion of the hole for forming the void, and when it exceeds 70 μm. In the subsequent step of thinning the metal foil, it becomes difficult to uniformly reduce the thickness. The type of the metal foil is preferably a copper foil for forming a circuit or the like.

When a copper foil with a carrier is used, a general-purpose peelable metal foil such as Cu or Al, a fluorine-based easily peelable film material, a glass plate, or a metal such as a mirror-finished stainless steel is used for the carrier. An example of a metal foil from which a carrier can be peeled is a peelable copper foil, a carrier copper 70 μm / ultra-thin copper 9 μm DO
UBLETHIN9 / 70 (Furukawa Circuit Foil Co., Ltd., trade name), etc., peelable copper foil of aluminum carrier can be used, or composite foil consisting of two or more metal layers that can be removed by etching etc. Can be used, carrier copper / nickel layer / ultra-thin copper 5
μm CCT-FOIL (manufactured by Nippon Electrolysis Co., Ltd.
Product name).

In the case of a metal foil having a thickness of 3 to 9 μm, commercially available ultra-thin copper foil, ultra-thin copper foil with an aluminum carrier, or carrier copper 70
DOUBLETHIN 9/70 of μm / ultra-thin copper 9 μm
(Made by Furukawa Circuit Foil Co., Ltd.) and copper (carrier) / nickel alloy (stopper)
/ Copper (ultra-thin copper) composite foil, and CCT-FOIL (trade name, manufactured by Nippon Electrolysis Co., Ltd.) can be used as a commercially available composite foil.

For the purpose of the present invention, the accuracy of the thickness of the metal foil is extremely important. From the results of experiments conducted by the present inventors, it is necessary to reduce the variation in the resistance of the current protection element to 15% or less. Requires that the accuracy of the thickness of the metal foil be within ± 5%, and that the accuracy of the thickness of the metal foil be within ± 3% in order to suppress the variation in resistance to 12% or less. It has been found that the above-mentioned ultra-thin copper foil and composite foil are manufactured by an electrolytic method or a rolling method, and the thickness accuracy thereof is extremely good even if it is generally available. Measurement (for composite foil, measure by dissolving ultra-thin copper layer)
As a result, the average value is about ± 1% for the same lot product, and it is sufficiently possible to suppress the resistance variation to 12% or less.

In order to laminate and bond the metal foil with carrier and the first insulating layer, a hole for forming a gap is provided between the first insulating layer having a hole for forming a gap and the metal foil with a carrier. Can be laminated and bonded by this adhesive layer. At this time, from the viewpoint of preventing the gap between the first insulating layer and the adhesive layer from forming the hole for forming the void, the gap for forming the void is also required. It is preferable to form an adhesive layer on the surface of the first insulating layer in which a hole is to be formed, and at the same time, after forming a hole for forming a void, to laminate and bond with a metal foil with a carrier. In this case, to form an adhesive layer on the surface of the first insulating layer, the semi-cured adhesive layer is pressed or roll-laminated, or a varnish of the adhesive layer is applied to the surface of the first insulating layer. It may be formed by coating and drying.

After laminating and bonding the metal foil with carrier and the first insulating layer and the second insulating layer each having a hole for forming a gap, in order to efficiently form a circuit, the holes for forming the gap are required. Is preferably embedded with a resin that can be removed. Examples of commercially available resin for filling holes include SER-410CL (trade name, manufactured by Yamaei Chemical Co., Ltd.) and SER-391B (trade name, manufactured by Yamaei Chemical Co., Ltd.). Can be used, these are 40
It can be easily removed with a 3 to 5% by weight aqueous NaOH solution at ６０60 ° C., and can be removed after circuit formation.

(Step c) In order to reduce the thickness of the laminated and bonded metal foil, when a thicker metal foil is used, it is preferable to remove the metal foil by etching away in the thickness direction with an etchant, and to reduce the thickness of the copper foil to a thickness of 15 μm or more. Examples of the etchant for uniformly thinning the foil to 3 to 9 μm include copper chloride, iron chloride, an alkaline etchant, and a sulfuric acid-hydrogen peroxide etchant when a metal foil is a preferable copper foil. Commercially available sulfuric acid with excellent film thickness uniformity
Hydrogen peroxide-based etchants are good, and commercially available products include Permaetch (trade name, manufactured by Ebara Densan Co., Ltd.), SE-0
7 (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name) and the like.

When a metal foil with a carrier is used, the carrier can be removed by removing the carrier, and the first laminated and adhered metal foil is used.
In order to remove the carrier from the insulating layer, in the case of an ultra-thin copper foil with an aluminum carrier or a peelable copper foil, at the boundary between the carrier exposed on the side and the metal foil of 3 to 9 μm,
You can cut off a sharp edge like a knife, pinch the fragment with your finger and peel it off,
In the case of a composite foil of carrier / stopper / ultra-thin copper, the carrier and the stopper can be etched and removed by immersing the carrier and the stopper in a chemical etching solution or spraying a chemical etching solution.

(Step c1) At this time, in order to increase the thickness of the connection wiring, it is possible to leave only the portion of the connection wiring. It is sufficient to form an etching resist in the shape of the wiring, and when using a metal foil with a carrier, use a metal for the carrier and, when removing the metal by etching, similarly apply the etching resist to the shape of the connection wiring. In this case, the carrier can be formed in the shape of the connection wiring.

(Step d) In order to remove unnecessary portions of the metal foil by etching, an ink for an etching resist is silk-screen printed, or a dry film for an etching resist is laminated, and the photo-resist is adjusted to the shape of the resist to be formed. By exposing and developing ultraviolet rays through a mask to form a shape that remains without being etched away, it can be etched and removed by dipping in a chemical etching solution or spraying a chemical etching solution. And the connection wiring between the electrode and the current protection element can be formed.

If the connection wiring is not thickly left in the previous step, a metal foil having a thickness of 3 to 9 μm is plated in advance so that the connection wiring has a thickness of 10 to 50 μm. Can be performed, and the connection reliability between the electrode and the current protection element is improved, which is preferable. Such plating is performed by forming a resist pattern for plating, and then forming a metal foil having a thickness of 3 to 9 μm attached to an insulating substrate so that the thickness of a portion serving as an electrode is 10 to 50 μm. This is possible by performing electrolytic copper plating.

(Step e) A second insulating layer having a gap aligned with the position of the current protection element, and a second insulating layer having a metal foil bonded to only one surface, which is superimposed on the outside of the first insulating layer and the second insulating layer. For the insulating layer of No. 3, a prepreg, a resin film, or the like can be used. Commercially available prepregs include GEA
-E-679N (trade name, manufactured by Hitachi Chemical Co., Ltd.), and GF3500 as a commercially available resin film.
(Trade name, manufactured by Hitachi Chemical Co., Ltd.). The bonding between the first insulating layer and the second insulating layer having holes for forming voids and the third insulating layer may be performed using an adhesive layer having holes for forming voids. The thickness of the adhesive layer is 2
The range is preferably from 0 to 200 µm, more preferably from 40 to 100 µm. The thickness of this interlayer adhesive layer is 20 μm
If the thickness is less than 200, the connection wiring is insufficiently buried and may be peeled off in the subsequent steps. If the thickness exceeds 200 μm, the resin flow becomes large, flows into the hole for forming the void, and the void is crushed. There is a risk. The resin flow of the interlayer adhesive layer is preferably 200 μm or less, and this resin flow is 50 μm thick and 5 mm in diameter.
Heat the sample with the holes
When pressurized, it refers to the distance of the resin that has flowed into the hole from the edge of the hole.

A third metal foil is adhered to only one side of the metal foil.
The insulating layer of the above, so that the metal layer is on the outside, can be performed by laminating and pressurizing and heating sandwiching the adhesive layer with holes for forming the gap, or It can also be performed by laminating an adhesive layer having holes for forming voids on the third insulating layer, and then applying pressure and heat.

(Step f) A hole for an electrode can be made at a location of the connection wiring of the laminated and bonded object by a usual numerically controlled drill machine.

(Step g) The plating and the electrical connection between the connection wiring and the metal foil can be carried out in the same manner as in a normal through-hole plating of a wiring board, and the smear in the through-hole is removed. Performing desmearing, or performing electroless plating by performing thin electroless plating, or can be achieved by performing thick electroless plating, and the plating thickness is 5 to 50 μm, more preferably 10 to 30 μm. Range.

(Step h) In order to form an electrode by removing portions other than the electrode by etching, an etching resist is formed in the shape of the electrode, and a portion not covered with the etching resist is immersed in a chemical etching solution. Alternatively, the etching can be carried out by spraying a chemical etching solution to remove by etching.

(Step i) Between adjacent current protection elements:
In order to cut each chip-type current protection element in which electrodes at both ends are formed by cutting at the locations of the holes and holes, a dicing machine having a rotary blade can be used.

[0040]

EXAMPLE 1 (Step a) As shown in FIG. 1 (a), MCL-E is a 0.2 mm thick double-sided copper-clad laminate in which copper foil having a thickness of 18 μm is bonded to both sides. -679 (trade name, manufactured by Hitachi Chemical Co., Ltd.), the two insulating plates 11 and 12 obtained by etching and removing the copper foils on both surfaces of the first insulating layer and the second insulating layer, respectively.
GF, which is a resin film 3 on one side.
3500 (manufactured by Hitachi Chemical Co., Ltd., trade name) was heated and pressed under a pressing condition of a temperature of 80 ° C., a time of 10 minutes, and a pressure of 30 kgf / cm ² , and was temporarily bonded, and two insulating plates 101 with a resin film were used. , 102 were prepared, and a hole 4 having a diameter of 0.8 mm for forming a void was formed in each of the holes by a drill machine.

(Step b) As shown in FIG. 1B, NDGR-18 (trade name, manufactured by Nippon Electrolysis Co., Ltd.), which is a copper foil 6 having a thickness of 18 μm, and an insulating plate 101 with a resin film are overlapped. Combined, temperature 170 ° C, time 60 minutes, pressure 20k
Under the condition of gf / cm ² , heating and pressurizing, laminating and integrating,
Further, SER-410CL (trade name, manufactured by Yamaei Chemical Co., Ltd.), which is a filling resin 42, is embedded in the holes 4 for forming the gaps of the laminated substrate by silk-screen printing, and the embedded surface is chemically resistant. As the protective film 41, L1240H (trade name, manufactured by Hitachi Chemical Co., Ltd.), a film having a thickness of 80 μm, was attached.

(Step c1) Next, as shown in FIG. 1 (c1), H-K45 which is a dry film having a thickness of 50 μm is used.
No. 0 (trade name, manufactured by Hitachi Chemical Co., Ltd.) is laminated on the surface of the copper foil 6, irradiated with ultraviolet rays through a photomask masking portions other than the connection wiring 71, developed, and developed. An etching resist is formed in a shape, and an etching solution SE-07 (manufactured by Mitsubishi Gas Chemical Company, Inc.
(Trade name), the copper foil 6 was etched away in the thickness direction, the connection wiring 71 was 18 μm, and the other portions were 5 μm.
m.

(Step d) Subsequently, as shown in FIG. 1D, after the etching resist is removed, a dry film H-K450 (trade name, manufactured by Hitachi Chemical Co., Ltd.) is used.
It is laminated on the surface of the copper foil 6, irradiated with ultraviolet rays through a photomask masking portions other than the current protection element 8 and the connection wiring 71, developed, and developed.
An etching resist is formed so as to cover the first location,
Using a copper chloride etching solution, the portions not covered with the etching resist are removed by etching, and the current protection element 8 is removed.
And the connection wiring 71 were formed. At this time, as shown in FIG. 1 (D), the plurality of current protection elements 8 are arranged in series in the vertical direction with the connection wiring 71 interposed therebetween, and are arranged in the horizontal direction so as to be arranged in parallel. After that, the protective film 41 on the back surface was peeled off, and then immersed in a 4% by weight NaOH aqueous solution at 60 ° C. to dissolve and remove the filling resin in the holes 4 for forming the voids.

(Step e) As shown in FIG. 1 (e), holes are formed at the positions of the substrate on which the current protection element 8 and the connection wiring 71 are formed, the insulating plate 102 with the resin film, and the holes 4 for forming the gaps. GF3500 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is an opened resin film 3, and single-sided copper-clad laminates 111 and 112 each having a thickness of 0.2 mm and a copper foil 72 having a thickness of 18 μm bonded to one side. Two pieces of MCL-E-679 (trade name, manufactured by Hitachi Chemical Co., Ltd.) are placed on a single-sided copper-clad laminate 111 with the copper foil 72 facing down, and the resin film 3 and the insulating plate 11 are placed thereon. Current protection element 8 and connection wiring 7
The hole 4 for forming a gap is formed by a current protection element in the order of the substrate on which the substrate 1 is formed, the insulating plate 102 with the resin film with the resin film 3 down, the resin film 3 and the single-sided copper-clad laminate 112 with the copper foil 72 up. 8 position, piled up, temperature 180 ° C, time 60 minutes, pressure 50kgf / c
The layers were integrated by heating and pressing under the conditions of m ² .

(Step f) As shown in FIG. 1 (f), a hole having a diameter of 0.35 m was formed at the position of a drilling guide provided at the end of the laminated substrate by using a drilling machine with an X-ray fluoroscope.
and a hole 0.7 mm in diameter at the connection wiring 71 connecting between the current protection elements 8 arranged and designed based on the hole.
A hole 801 of mm was made.

(Step g) As shown in FIG. 1 (g), a pre-process of electroless plating was performed on the holed substrate, and an L-59 plating solution as an electroless copper plating solution (Hitachi Chemical Industry Co., Ltd.) (Manufactured by the company, trade name) at 70 ° C for 12 hours,
Copper plating 73 having a thickness of 24 μm was formed.

(Step h) Subsequently, as shown in FIG. 1H, a dry film H-K450 (trade name, manufactured by Hitachi Chemical Co., Ltd.) was laminated on the surface of the plated copper foil, and holes 801 were formed. UV light is irradiated through a photomask that masks other than the location of the electrode 7 to be formed at the location of the electrode 7 and developed, an etching resist is formed so as to cover the location of the electrode 7, and etching is performed using a copper chloride etching solution. A plurality of electrodes 7 were formed by etching away portions not covered with the resist. The arrangement of the electrodes 7 at this time is shown in FIG.
As shown in (i), they were arranged vertically and horizontally.

(Step i) As shown in FIG. 1 (i), in the direction in which the current protection element 8 and the connection wiring 71 are arranged so as to be connected, the hole 801 is cut so as to be divided. In the perpendicular direction, the space between the adjacent current protection elements 8 was cut, and the electrodes 7 were cut into individual chip-type current protection elements formed at both ends thereof.

Comparative Example 1 A chip-type current protection element was manufactured in the same manner as in Example 1 except that the holes 4 for forming voids were not formed in the insulating plates 101 and 102 with a resin film.

Comparative Example 2 A chip-type current protection device was manufactured in the same manner as in Example 1 except that the copper foil 6 was not thinned.

Circuits were formed on the chip-type current protection elements manufactured in the examples and comparative examples so that the resistance value was about 100 mΩ. (Resistance value) 100 resistances were extracted at random, the resistance value was measured, and the number of chip-type current protection elements having a resistance value within a range (within ± 10%) was counted. (Fusing time) Fusing time was measured only for 100 pieces having a resistance value within the above range. The fusing current value is 1.
6A, and the fusing test was performed by adjusting the voltage value so that no rush current was generated by the oscilloscope. (Residual resistance value) The resistance value after fusing was measured, and the number of 1 MΩ or more was counted. (Ignition / smoke) During the fusing test, the presence or absence of ignition / smoke was visually checked, and the number of those without ignition / smoke was counted. Table 1 shows the results.

[0052]

[Table 1]

From these results, it can be seen that, in the example, the variation in the resistance value of the fuse element was small and the fusing characteristics were excellent. Of several kilohms, and smoke was also observed. When the thick copper foil of Comparative Example 2 was used, the current protection element 8 was used to obtain the same resistance value as in the example.
It was necessary to form the circuit width of about 25 μm, but the precision by the etching process could not catch up, the resistance value largely fluctuated, and the fusing time fluctuated greatly even after sorting.

[0054]

As described above, according to the present invention, the current protection element is excellent in forming accuracy (thickness and width of wiring), is excellent in suppressing heat radiation, and suppressing smoke and ignition, and further, after fusing. And a highly reliable chip-type current protection element having high insulation resistance and a method of manufacturing the same.

[Brief description of the drawings]

FIG. 1 (a), (b), (c1), (d) to (h)
FIGS. 3A and 3B are cross-sectional views in respective steps showing one embodiment of the present invention, FIG. 4D is a top view of FIG. 4D, and FIG.

[Explanation of symbols]

 11.12. Insulating plate 101, 102. Insulating plate with resin film 111, 112. 2. Single-sided copper-clad laminate Resin film 4. Hole for forming void 41. Protective film 42. Filling resin 6. Copper foil 7. Electrode 71. Connection wiring 72. Copper foil 73. Copper plating 8. Current protection element 801. hole

Claims (5)

[Claims] 1. A method comprising: a. Manufacturing a first insulating layer and a second insulating layer having two holes for forming gaps, b. Laminating and bonding the metal foil to the first insulating layer; c. Thinning the metal foil to a thickness of 3-9 μm, d. Forming a plurality of current protection elements, electrodes, and connection wiring between the electrodes and the current protection element such that the unnecessary parts of the metal foil are removed by etching so that the current protection elements are located at the positions of the holes for forming voids; e. . A second insulating layer in which a hole for forming a gap is aligned with the position of the current protection element, and a first insulating layer and an outer side of the second insulating layer,
A step of laminating a third insulating layer having a metal foil bonded to only one side thereof with an adhesive layer so that the metal layer is on the outside, and laminating and bonding; f. Making a hole for an electrode at a location of the connection wiring of the laminated and bonded object; g. Plating and electrically connecting the connection wiring and the metal foil; h. Forming an electrode by etching away portions other than the electrode, i. Manufacturing a chip-type current protection element characterized by comprising a step of cutting into individual chip-type current protection elements in which electrodes at both ends are formed by cutting between adjacent current protection elements and at locations of holes. Law. 2. a. Manufacturing a first insulating layer and a second insulating layer having two holes for forming gaps, b. Laminating and bonding the metal foil to the first insulating layer; c1. 3 to 9 places other than the place to be the connection wiring of the metal foil
thinning to a thickness of μm, d. Forming a plurality of current protection elements, electrodes, and connection wiring of the current protection element by etching and removing unnecessary portions of the metal foil so that the current protection elements are located at the locations of the holes where the voids are required; e. A second insulating layer in which a hole for forming a gap is aligned with a position of the current protection element, and a first insulating layer and an outer side of the second insulating layer,
A step of stacking and laminating a third insulating layer in which a metal foil is stuck on only one side of the two sheets via an adhesive layer such that the metal layer is on the outside, f. Making a hole for an electrode at a location of the connection wiring of the laminated and bonded object; g. Plating and electrically connecting the connection wiring and the metal foil; h. Forming an electrode by etching away portions other than the electrode, i. Manufacturing a chip-type current protection element characterized by comprising a step of cutting into individual chip-type current protection elements in which electrodes at both ends are formed by cutting between adjacent current protection elements and at locations of holes. Law. 3. The metal foil is a metal foil with a carrier,
A first copper layer having a thickness in the range of 10 to 50 μm;
2. A composite metal foil comprising a second copper layer having a thickness in the range of m and a nickel or alloy layer thereof having a thickness of 1 μm or less as an intermediate layer between the two copper layers. 3. The method for manufacturing a chip-type current protection device according to item 2. 4. The method according to claim 1, further comprising a step of plating the metal foil having a thickness of 3 to 9 μm after the carrier is removed so that the thickness of the connection wiring is 10 to 50 μm. A method for manufacturing the chip-type current protection device according to claim 1. 5. The method according to claim 1, wherein a resin having a resin flow of 200 μm or less is used as an adhesive layer for bonding the third insulating layer to the first insulating layer and the second insulating layer. A method for manufacturing the chip-type current protection device according to any one of the above.