JP2000021611A - Current protecting chip element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase forming precision and restrain heat dissipation, smoking and firing, by defining the thickness of current protecting chip elements and arranging gaps on both surfaces in the vicinity of a part to be fused. SOLUTION: A metal foil with a carrier which is constituted of a carrier and a metal foil of 3-9 μm in thickness, and an insulating plate 101 with a resin film are so overlapped that a very thin copper 61 is in contact with a resin film 3. Hole filling resin 42 is buried in holes 4 for gap formation of a laminated board, and a protective film 41 having chemical resistance is stuck. A board on which current protecting elements 8 and connection wirings 71 are formed, an insulating plate 102 with a resin film, a resin film 3 where holes are bored in the parts of the holes 4 for gap formation, and a copper foil 72 of 18 μm in thickness are stuck on a single surface. Holes 801 are made in the parts of the connection wirings 71 between the current protecting elements 8. The holes 801 are cut to be divided. In the direction perpendicular to the division, parts between adjacent current protecting elements 8 are cut, and the laminated board is divided into the respective current protecting chip elements in which electrode are formed on both ends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chip-type current protection device and a method for manufacturing the same.

[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]

According to the present invention, there is provided a chip-type current protection element comprising: a current protection element; insulating layers provided on both sides of the current protection element; and a pair of electrodes connected to the current protection element. The current protection element is characterized in that the thickness of the current protection element is 3 to 9 μm, and that a gap is provided on at least both surfaces of the current protection element near a portion to be blown.

The thickness of the connection between the current protection element and the electrode is
It can be 10 to 50 μm.

Such a chip-type current protection element includes: 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 attaching a metal foil with a carrier comprising a carrier and a metal foil having a thickness of 3 to 9 μm to a first insulating layer; c. Removing the carrier from the laminated first insulating layer; 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 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. It can be manufactured by a manufacturing method including a step of cutting into individual chip-type current protection elements formed with electrodes at both ends by cutting between adjacent current protection elements and at holes.

The metal foil with a carrier has a first copper layer having a thickness in the range of 10 to 50 μm, a second copper layer having a thickness in the range of 3 to 9 μm, and an intermediate layer between the two copper layers. Thickness 1
A composite metal foil having a nickel or alloy layer of μm or less 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.

After the carrier has been removed, the first copper layer and the nickel or alloy layer thereof may be removed only at the portion to be the current protection element.

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.

[0020]

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 portion between the current protection element and the electrode is preferably in the range of 10 to 50 μm because of a change in the environmental temperature at a place where the current protection element is installed, and a change in the current flowing through the element itself. Since the thermal stress caused by the temperature change due to the off state tends to concentrate on the point where the current protection element and the electrode are connected, the thickness is more effective as the thickness is increased. , Increase in materials, changes in lamination bonding conditions due to a decrease in embedding properties due to the resin material, etc.), and when the thickness exceeds a certain level, the degree of improvement in the effect is reduced even if the thickness is further increased. It is.

(Step a) It is desirable to use a base material composed of a resin and a reinforcing material for the first insulating layer and the second insulating layer of the present invention. A resin or the like can be used, and a reinforcing material selected from glass cloth and glass paper can be used.

In order to form holes for forming voids in the first insulating layer and the second insulating layer, a drill machine generally used for drilling through holes or the like in a wiring board can be used.

(Step b) As the carrier, a general-purpose peelable metal foil such as Cu or Al, a fluorine-based easily peelable film material, a glass plate, or a metal plate such as a mirror-finished stainless steel is used. Metal foil is preferable, but examples of the metal foil from which the carrier can be peeled include carrier copper 70 μm / ultra-thin copper 9 called peelable copper foil.
DUBBLETHIN 9/70 (Furukawa Circuit Foil Co., Ltd., trade name), etc., and ultra-thin copper foil (peelable copper foil) with an aluminum carrier can be used, or two types that can be removed by etching or the like A composite foil composed of the above metal layers can also be used, and a CCT-layer composed of carrier copper / nickel layer / ultra-thin copper 5 μm.
FOIL (manufactured by Nihon Denki Co., Ltd., trade name) and the like.

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 remove the carrier from the laminated and bonded first insulating layer, in the case of an ultra-thin copper foil with an aluminum carrier or a peelable copper foil, the carrier exposed on the side face is 3 to 9 μm. A sharp edge like a knife is cut into the boundary of the metal foil, and the fragment can be peeled by pinching it with a finger and peeling it off. In the case of the 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 the chemical etching solution or spraying the chemical etching solution.

(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 a photo-responding 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.

After the carrier is removed, the metal foil having a thickness of 3 to 9 μm can be plated in advance so that the thickness of the connection wiring is 10 to 50 μm. Connection reliability is improved. In such plating, after removing a carrier, a plating resist pattern is formed, and then, a metal foil having a thickness of 3 to 9 μm attached to an insulating substrate has a thickness of a portion serving as an electrode having a thickness of 10 μm.
This is possible by performing electrolytic copper plating so as to have a thickness of about 50 μm.

Alternatively, a carrier and a thickness of 3 to 9 μm
CCT-FOI consisting of carrier copper (18 μm) / nickel layer (0.1 μm) / ultra-thin copper 5 μm
Using L (manufactured by Nihon Electrolysis Co., Ltd., a trade name), an etching resist is formed at a portion to be a connection wiring, carrier copper is removed by etching with an alkaline etching solution, and a nickel layer is formed by Melstrip N-950 (Meltex Co., Ltd.). It can also be removed by etching with a nickel etchant such as a company (trade name, trade name) or nickel stripper BR (trade name, manufactured by McDermit Japan Co., Ltd.). In this case, the connection between the electrode and the current protection element can be left thick. ,preferable.

In this case, there is a place of ultra-thin copper 5 μm and a place where carrier copper and nickel layer remain, and the surface is uneven. Therefore, in order to form an etching resist, the photosensitive resin and the film are deposited by electrodeposition. Using an etching resist that can be formed on the surface, by exposing and developing ultraviolet rays through a photomask that matches the shape of the resist to be formed, it is formed into a shape that remains without being etched away, and immersed in a chemical etching solution or chemically The etching solution can be removed by etching by spraying or spraying, so that a plurality of current protection elements and electrodes and connection wiring between the current protection elements can be formed.

(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 resin film or a resin film can be used.
EA-E-679N (trade name, manufactured by Hitachi Chemical Co., Ltd.), and GF35 as a commercially available resin film.
00 (manufactured by Hitachi Chemical Co., Ltd., trade name). Adhesion between the first insulating layer and the second insulating layer having holes for forming voids and the third insulating layer can 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 first insulating layer and a second insulating layer each having a hole for forming a gap, and a third insulating layer in which a metal foil is bonded to only one surface of the first insulating layer and the second insulating layer are stacked such that the metal layer is on the outside. hand,
Lamination bonding can be carried out by overlapping and pressing and heating the adhesive layer having holes for forming voids, or an adhesive layer having holes for forming voids in the third insulating layer. And then pressurizing and heating.

(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, as a metal foil with a carrier comprising a carrier 5 and a metal foil 6 having a thickness of 3 to 9 μm, a carrier copper 51 having a thickness of 18 μm / a thickness of 0.1 μm. 1 μm nickel layer 91/5 μm thick ultra-thin copper 6
1 and the insulating plate 101 with a resin film are superimposed on each other so that the ultra-thin copper 61 and the resin film 3 are in contact with each other, and the temperature is 170 ° C. and the time is 60 minutes. Under the condition of a pressure of 20 kgf / cm ² , heating and pressurizing are performed, and the laminate is integrated. Further, SER-410CL (manufactured by Yamaei Chemical Co., Ltd., trade name) which is a filling resin 42 is used for forming a void in a substrate on which the laminate is formed. In hole 4,
Embed by silk screen printing, and as a chemical resistant protective film 41 on the embedded surface, a thickness of 80 μm
L1240H (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is a film of m.

(Step c) Next, as shown in FIG. 1 (c), the carrier copper 51 is removed by etching with an alkali etching solution, and the nickel layer 91 is further melted with a nickel strip N-950 (melting strip). This was removed by etching using Tex Corporation, trade name) to expose the ultra-thin copper 61.

(Step d) Thereafter, H-K450 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is a dry film having a thickness of 50 μm, is laminated on the surface of the ultra-thin copper 61, and only the portion of the connection wiring 71 is removed. Ultraviolet light is irradiated through a masked photomask, developed, and a plating resist is formed so as to cover portions other than the connection wiring 71. Electroplating with copper sulfate is performed at a current density of 4 A / dm ² and a temperature of 25. ° C
For 40 minutes to reduce the thickness of the connection wiring 71 to 20 μm. Subsequently, as shown in FIG. 1D, after the plating resist was removed, a dry film H-K450 (trade name, manufactured by Hitachi Chemical Co., Ltd.) was laminated on the surface of the ultra-thin copper 61 to protect the current. Ultraviolet rays are irradiated and developed through a photomask masking portions other than the element 8 and the connection wiring 71, and an etching resist is formed so as to cover the current protection element 8 and the connection wiring 71, and copper chloride etching is performed. Using a liquid, portions not covered with the etching resist were removed by etching, so that the current protection element 8 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.

Example 2 (Step a) A copper foil having a thickness of 18 μm was attached to both sides.
MCL-E- is a double-sided copper-clad laminate of 0.2mm thickness
679 (manufactured by Hitachi Chemical Co., Ltd., trade name) were used as the first insulating layer 1 and the second insulating layer 2, respectively, with the two insulating plates 11 and 12 from which the copper foils on both surfaces were removed by etching. GF3500 (trade name, manufactured by Hitachi Chemical Co., Ltd.) as a resin film 3 was heated at 80 ° C. for 10 minutes.
Under a pressing condition of a pressure of 30 kgf / cm ² , heat and pressure are applied to temporarily bond the two, and the two insulating plates 101 with a resin film,
No. 02 was prepared, and a hole 4 having a diameter of 0.8 mm for forming a void was formed in each of them by a drill machine.

(Step b) As a metal foil with a carrier comprising a carrier 5 and a metal foil 6 having a thickness of 3 to 9 μm,
DOUBLETHIN 9/70 (trade name, manufactured by Furukawa Circuit Foil Co., Ltd.) composed of 0 μm carrier copper 51/9 μm thick ultra-thin copper 61 and insulating plate 101 with a resin film were combined with ultra-thin copper 61 and resin film 3. Are superimposed on each other, and the temperature is 170 ° C., the time is 60 minutes, and the pressure is 2
Under the condition of 0 kgf / cm ² , heating and pressurization were performed to laminate and integrate. Furthermore, SER-410CL which is a resin for filling holes
(Trade name, manufactured by Yamaei Chemical Co., Ltd.) is buried in the holes 4 of the laminated substrate by means of silk screen printing, and the buried surface is further coated with a chemical-resistant protective film 41.
L1240H which is a film having a thickness of 80 μm
(Trade name, manufactured by Hitachi Chemical Co., Ltd.).

(Step c) Next, the carrier copper 51 of 70 μm was manually peeled off.

(Step d) Thereafter, H-K450 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is a dry film having a thickness of 50 μm, is laminated on the surface of the ultra-thin copper 61, and only a portion of the connection wiring 71 is removed. Ultraviolet light is irradiated through a masked photomask, developed, and a plating resist is formed so as to cover portions other than the connection wiring 71. Electroplating with copper sulfate is performed at a current density of 4 A / dm ² and a temperature of 25. ° C
For 40 minutes to reduce the thickness of the connection wiring 71 to 20 μm. Thereafter, a chip-type current protection element was manufactured in the same manner as in Example 1.

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 copper foil having a thickness of 12 μm, YGR-12 (trade name, manufactured by Nippon Electrolysis Co., Ltd.) was used in place of the copper foil with a carrier.
Example 1 except that the step of removing the carrier was not performed.
In the same manner as in the above, a chip-type current protection element was manufactured.

Comparative Example 3 An NDGR-18 (trade name, manufactured by Nippon Electrolysis Co., Ltd.), a 18-μm-thick copper foil, was used in place of the copper foil with a carrier, except that the step of removing the carrier was not performed. In the same manner as in Example 1, a chip-type current protection element was manufactured.

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.

[0057]

[Table 1]

As can be seen from the results, in the example, the variation in the resistance value of the current protection element 8 was small and the variation in the fusing time was small, whereas in the comparative example 1 in which no hole for forming a gap was formed, Some have a residual resistance of several KΩ,
Some smokes were also observed. In Comparative Example 2, the resistance value of the current protection element 8 greatly fluctuated, and the fusing time also fluctuated widely. In Comparative Example 3, the copper foil forming the current protection element 8 was thick. In order to obtain the same resistance value as in the example, it is necessary to form the circuit width of about 25 μm. However, since it is difficult to perform etching with such accuracy, the resistance value varies greatly, and even if the selected one is used, the fusing time is reduced. Was large.

[0059]

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]

1 (a) to 1 (h) are cross-sectional views in respective steps showing one embodiment of the present invention, (D) is a top view of (d), and (i) is a top view. is there.

[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 5. Carrier 51. Carrier copper 6. 61. Copper foil having a thickness of 3 to 9 μm Ultra-thin copper 91. Nickel layer 7. Electrode 71. Connection wiring 72. Copper foil 73. Copper plating 8. Current protection element 801. hole

Claims (7)

[Claims] 1. A chip type current protection element comprising a current protection element, insulating layers provided on both surfaces thereof, and a pair of electrodes connected to the current protection element, wherein the thickness of the current protection element is 3 to A chip-type current protection element having a thickness of 9 μm and having air gaps at least on both surfaces near a portion to be blown of the current protection element. 2. The thickness of the connection between the current protection element and the electrode is
The chip type current protection device according to claim 1, wherein the thickness is 10 to 50 m. 3. A method according to claim 1, Manufacturing a first insulating layer and a second insulating layer having two holes for forming gaps, b. Laminating and bonding a metal foil with a carrier comprising a carrier and a metal foil having a thickness of 3 to 9 μm to a first insulating layer; c. Removing the carrier from the laminated and bonded first insulating layer; 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 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. 4. A metal foil with a carrier, wherein a first copper layer having a thickness in the range of 10 to 50 μm, a second copper layer having a thickness in the range of 3 to 9 μm, and an intermediate between the two copper layers. 1 layer thickness
4. The method for manufacturing a chip-type current protection device according to claim 3, wherein a composite metal foil having a nickel or alloy layer thereof having a thickness of not more than μm is used. 5. The method according to claim 1, further comprising a step of plating the metal foil having a thickness of 3 to 9 μm after removing the carrier 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 3. 6. The chip-type current protection device according to claim 4, wherein after removing the carrier, the first copper layer and the nickel or alloy layer thereof are removed only at a portion to be a current protection element. Device manufacturing method. 7. The method according to claim 3, wherein a resin having a resin flow of 200 μm or less is used for 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.