JP2566826Y2 - fuse - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuse for protecting circuit parts such as wiring from overcurrent.

[0002]

2. Description of the Related Art A blade-type fuse has two plate-like connection terminals arranged in parallel and a fusing portion bridged between the two connection terminals. The terminal is connected to the terminal on the power supply side, and the connection terminal on the other side is connected to the terminal on the load device side. When the current flowing from the connection terminal on one side to the connection terminal on the other side via the fusing portion exceeds the rated capacity, the fusing portion is blown off by heating, the circuit is cut off, and the circuit portion is protected from overcurrent. I have to.

A connection terminal of such a fuse is formed on a surface of a base material made of copper, a copper-based alloy, zinc or a zinc alloy, for example, brass or the like, with a metal coating for the purpose of improving corrosion resistance and contact characteristics. Are formed. As a metal coating material, tin (Sn) is often used from the viewpoint of economy, and is generally formed by a so-called wet process (wet process) such as an electrolytic plating method, an electroless plating method, and a hot dipping method. I was

[0004]

However, in the connection terminal of the conventional fuse, the base material constituent elements (Cu, Zn)
Is problematic to the tin film side. In particular, when the environmental temperature is increased, the above-described diffusion phenomenon appears remarkably. For example, the copper element of the base material diffuses to the tin film side, and an alloy is formed by copper and tin. This alloy of copper and tin has a high hardness, and deteriorates adhesion when contacting an external terminal, thereby increasing contact resistance. Further, when the zinc element of the base material is diffused, it deposits on the surface of the tin film to form zinc oxide having low conductivity on the surface of the tin film, and the contact resistance increases as described above.

For this reason, in a fuse having such a connection terminal, the base material constituent element is diffused as described above due to an increase in the use environment temperature and heat generated from the fusing portion, and the connection terminal and the external terminal are not connected to each other. The contact resistance in the contact area increases. As a result, there is a problem that the current value and the voltage value of the current flowing in the fuse are changed, and the reliability is deteriorated. Further, when the contact resistance increases, a large amount of heat is generated, and the heat is transmitted to the fusing portion, so that the fusing portion is blown even if the current does not exceed the rated capacity.

On the other hand, a technique has been developed in which a zinc diffusion barrier layer made of pure copper is formed between a base material and a tin film as a connection terminal of a fuse, and the barrier layer suppresses the diffusion of constituent elements of the base material. ing. However, also in this case, an alloy having high hardness similar to the above is formed due to the interdiffusion between copper of the barrier layer and tin of the tin film, and the contact resistance is still increased. In particular, when the alloying of pure copper and tin progresses and the alloy layer reaches the interface with the base material, the alloy layer promotes the diffusion of zinc element in the base material, and a large amount of zinc element is deposited on the tin film surface. Precipitation causes the same problem as described above.

The present invention solves the above-mentioned problems of the prior art, suppresses the diffusion of the constituent elements of the base material of the connection terminal, is excellent in reliability, and has a fuse capable of preventing the fusing portion from being blown below the rated electric capacity. The purpose is to provide.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to two connecting terminals having a tin film formed on a surface of a base material made of copper, a copper-based alloy, zinc or a zinc-based alloy, and a connection between the two terminals. Having a passed conductive fusing portion, each connection terminal is a fuse connected to an external terminal respectively, in order to achieve the above object, between the base material of the connection terminal and the tin film A tin oxide film is formed.

[0009]

In the electrical contact material according to the present invention, since the tin oxide film having a dense structure is formed between the base material and the tin film in the connection terminal, the temperature rises in the use environment and occurs from the fusing portion. Diffusion of the constituent elements of the base material to the tin film side can also be suppressed by heat, and the contact resistance of the connection terminal decreases. For this reason, the current value and the voltage value of the current flowing in the fuse can be prevented from changing, and the generation of heat can be suppressed.

[0010]

FIG. 1 shows a fuse 1 to which a first embodiment of the present invention is applied.
It is a schematic plan view which shows 00. As shown in FIG. 1, the fuse 100 has two plate-like connection terminals 110, 110.
And a fusing portion 120 bridged between the two connection terminals 110, 110, and the connection terminals 110, 1 together with the fusing portion 120.
A housing 1 attached so as to cover one end of the housing 10
30.

When the fuse 100 is manufactured, first, the connection terminals 11 are formed using a sputtering apparatus shown in FIG.
0 is formed. In the chamber 1 of the sputtering apparatus, an electrode (cathode) 2 for a target is disposed at an upper portion, and an electrode 3 for a base material is disposed at a lower portion. Further, the electrode 3 is grounded, and a high-frequency voltage is applied between the electrodes 2 and 3 by the power supply 4. In this case, a DC voltage may be applied between the electrodes 2 and 3. Further, an argon gas introducing means 5 for introducing an argon (Ar) gas and an oxygen gas introducing means 6 for introducing an oxygen (O ₂ ) gas are connected to the chamber 1. A vacuum exhaust means 7 for evacuating the inside of the device 1 is connected.

Then, tin (Sn) 10 is set as a target on the electrode 2 and a base material 11 made of, for example, brass made of copper, a copper-based alloy, zinc or a zinc-based alloy is set on the electrode 3. In this state, the inside of the chamber 1 is evacuated to a high vacuum by the vacuum evacuation means 7, and argon gas and oxygen gas are introduced into the chamber 1 by the argon gas introduction means 5 and the oxygen gas introduction means 6.
A high frequency voltage is applied between the three. As a result, plasma of argon gas and oxygen gas is generated between the target (10) and the base material 11, and argon ions in the plasma collide with the target 10 to strike out target particles (tin particles). Further, the target particles are reacted with the plasma of oxygen gas in the gas phase or on the surface of the base material to form tin oxide (SnO ₂ ).
1 on top.

Thus, a predetermined amount (0.2 μm or more) of tin oxide is deposited on the upper surface of the base material 11 to form a tin oxide film 12 as a diffusion barrier layer.

When the deposition of tin oxide is completed, the supply of oxygen gas by the oxygen gas introducing means 6 is stopped while the supply of argon gas is continued.

Thus, the tin particles beaten out by the argon gas plasma are deposited on the upper surface of the tin oxide film 12 to form the tin film 13.

In this manner, as shown in FIG. 3, a connection terminal material having the tin film 13 formed on the upper surface of the base material 11 with the tin oxide film 12 interposed therebetween is formed.

Next, the connection terminal material is cut into a predetermined shape to form connection terminals 110. Thereafter, as shown in FIG. 1, the housing 130 is attached after connecting both ends of the fusing portion 120 made of a linear metal material on the tin films of the two connection terminals 110, 110 by, for example, soldering. Thus, the fuse 100 is formed.

In the use state of the fuse 100, the contact region 1 formed by the other end of each of the connection terminals 110, 110
11, 111 (shown by hatched areas in FIG. 1) on the tin film,
The terminal on the external power supply side and the terminal on the load device side are connected respectively. Thereby, when the current flowing from one connection terminal 110 to the other connection terminal 110 via the fusing portion 120 exceeds the rated capacity, the fusing portion 120 is blown by heating, the circuit is cut off, and the circuit part is overheated. Protected from current.

According to the fuse 100, the connection terminal 1
In FIG. 10, the tin oxide film 12 having a dense structure is formed between the base material 11 and the tin film 13. Therefore, even when the use environment temperature rises and the heat generated from the fusing portion 120, the base material constituent elements ( The diffusion of Cu, Zn, etc.) to the tin film 10a side can be suppressed, and the contact resistance of the connection terminal 110 decreases. For this reason, it is possible to prevent the current value and the voltage value of the current flowing in the fuse from fluctuating, so that the reliability is excellent. Furthermore, since the contact resistance is low, the generation of heat can be suppressed in the contact area 111 of the connection terminal 110 with the external terminal when the fuse is used, the fusing of the fusing portion 120 due to the heat can be prevented, and before the current exceeds the rated capacity. There is no fusing of the fusing section 120.

Further, since inexpensive tin is used as a coating material for the base material 11, the cost can be reduced.

Further, by suppressing the diffusion of the zinc element from the base material 11, a decrease in the mechanical strength of the base material 11 can be prevented.

Note that tin oxide has a high conductivity (10 ^-4 Ω).
cm) Since it is an oxide, it does not hinder the fuse operation.

<Second Embodiment> In a second embodiment of the present invention, a material for connection terminals (FIG. 5) is used by using an ion beam mixing apparatus shown in FIG.
Reference).

Chamber 2 of ion beam mixing device
In 1, a sample holder 22 for holding the base material 31 is disposed at an upper portion thereof, and a crucible 23 for an evaporation source is disposed at a lower portion. Further, the chamber 21 is provided with oxygen supply means 24. Oxygen supply means 24
Has an oxygen gas supply means 25 and an oxygen gas ion source 26. The oxygen gas supplied from the oxygen gas supply means 25 is ionized by the oxygen gas ion source 26 to The material 31 can be irradiated in a beam shape. Further, the chamber 21 is connected to an evacuation unit 27 for evacuating the inside thereof, and a heating unit (not shown) for heating the evaporation source in the crucible 23 and the base material 31 on the sample holder 22. ) Are provided.

Then, a base material 31 made of, for example, brass made of copper, a copper-based alloy, zinc, or a zinc-based alloy is set in the sample holder 22, and tin (Sn) is accommodated in the crucible 23 as an evaporation source. In this state, the inside of the chamber 21 is evacuated to a high vacuum by the evacuating means 27.
The base material 31 and the evaporation source (tin) are heated by the respective heating means. Thereby, while the tin of the evaporation source is evaporated and the tin particles are vapor-deposited on one surface side of the base material 31, the one surface side of the base material 31 is irradiated with oxygen gas ions from the oxygen supply means 24, and Reacts tin with oxygen to form tin oxide, and deposits the tin oxide on one surface of the base material 31.

In this way, a predetermined amount (0.2 μm or more) of tin oxide is deposited on the base material 31 to form the first tin oxide film 32a.

When the deposition of tin oxide is completed, the irradiation of oxygen gas ions by the oxygen supply means 24 is stopped while the evaporation of tin continues.

Thus, the tin particles evaporated from the evaporation source are deposited on one surface of the base material 31 to form a tin film 33a.

Next, in the same manner as above, tin was added to the base material 31.
Irradiation of oxygen gas ions by the oxygen supply unit 24 is resumed while the second tin oxide film 32b having a thickness of 0.2 μm or more is formed on the tin film 33a.

Subsequently, the irradiation of oxygen gas ions is stopped, and the tin film 3 is formed on the second tin oxide film 32b in the same manner as described above.
3b is formed. Thereby, as shown in FIG. 5, a connection terminal material in which two layers of tin oxide films 32a and 32b are formed as a diffusion barrier layer is formed.

The connection terminal material thus formed is:
It is processed in the same manner as in the first embodiment, and is used as a connection terminal of a fuse.

According to this fuse, the two layers of tin oxide films 32a and 32b suppress the diffusion of the constituent elements of the base material at the connection terminals.
Compared with 00, the diffusion of the base material constituent elements can be suppressed more reliably, the reliability is further improved, and the fusing of the fusing portion below the rated electric capacity can be reliably prevented.

<Third Embodiment> FIG. 6 is an enlarged sectional view of a main part showing a connection terminal 210 of a fuse according to a third embodiment of the present invention. As shown in the figure, the connection terminal 210 of this fuse is formed by forming a copper layer (zinc diffusion barrier layer) 54 made of pure copper on a base material 51 made of brass by, for example, a wet process, and forming the copper layer 54. Above, a tin oxide film 52 and a tin film 53 are formed by the same method as in the above embodiment.

In connection terminal 210, the diffusion of zinc element in base material 51 is suppressed by copper layer 54 and tin oxide film 52, and the mutual diffusion of copper in copper layer 54 and tin in tin film 53 is oxidized. Suppressed by the tin film 52. Moreover, the copper layer 54 made of pure copper also has a function of adjusting the underlying substrate, and the surface of the copper layer 54 is flattened, and the adhesion of the tin film 53 is improved.

<Modification> In the above embodiment, the case where one or two tin oxide films are formed has been described. However, three or more tin oxide films may be formed.

Although the tin oxide film and the tin film are formed by using the sputtering method and the ion beam mixing method, they may be formed by using other methods.

In the above embodiment, the case where the present invention is applied to a blade type fuse has been described. However, the present invention can be applied to other types of fuses such as a glass tube type fuse.

<Experimental Example> In the same manner as in the first embodiment, a tin oxide film (SnO ₂ ) was formed on one surface of a base material made of brass (Cu, Zn) to a thickness of 0.2 μm. A tin film was formed to form a material for a connection terminal of the fuse. And the contact resistance value with respect to the load of the terminal material was measured. After further heating the electric contact material at 200 ° C. for 24 hours,
The measurement of the contact resistance value with respect to the load and the measurement of the element distribution in the terminal material by X-ray photoelectron spectroscopy (XPS) were performed. FIG. 7 shows the element distribution in the material by XPS, FIG. 8 shows the change in contact resistance before heat treatment, and FIG. 9 shows the change in contact resistance after heat treatment.
Are shown in the graphs. In this case, in the graph of FIG. 7, the horizontal axis shows the etching time (minute) corresponding to the depth position from the surface, and the vertical axis shows the abundance (%) of each element measured by XPS. Medium and white squares indicate copper, black solid circles indicate zinc, x indicates tin, and white circles indicate oxygen.
In the graphs of FIGS. 8 and 9, the horizontal axis indicates the load (gram), and the vertical axis indicates the contact resistance (ohm).

As a reference example, a conventional method
That is, the surface of the base material made of brass was coated with a tin film by a wet process to form a material for a connection terminal of the fuse. Then, the change in contact resistance with respect to the load of the contact material was measured. Further, after the electrical contact material was subjected to a heat treatment at 200 ° C. for 24 hours, a change in contact resistance with respect to a load was measured, and an element distribution in the material was measured by XPS. FIG. 10 shows the element distribution by XPS, FIG. 11 shows the contact resistance change before heat treatment, and FIG. 12 shows the contact resistance change after heat treatment.

As shown in FIG. 7, in the connection terminal material of the embodiment, the etching time is from the surface of the tin film of 0 minute to the boundary between the tin film and the tin oxide film at around 12 minutes, that is, in the tin film. Has a large amount of tin element (marked by x), and hardly any copper element (open square) or zinc element (closed circle) as a base material constituent element. Furthermore, in the tin oxide film whose etching time is from about 12 minutes to about 23 minutes, a large amount of tin and oxygen as constituent elements of the film are present, and other elements (copper and zinc) are almost present. Absent. From these points, it is considered that the diffusion of the base material constituent elements is suppressed by the tin oxide film, and the precipitation of the zinc element on the tin film surface and the formation of an alloy of copper and tin are both prevented. As described above, in the terminal material according to the example, even when the environmental temperature is high, the diffusion of the base material constituent elements is suppressed. Therefore, each contact resistance value after the heat treatment (FIG. 9) is equal to that before the heat treatment (FIG. 8). Compared to that, it has not increased much. As a result, when the terminal material of the embodiment is used as the connection terminal of the fuse, it is possible to prevent the current value and the voltage value of the current flowing in the fuse from fluctuating, and to generate heat in the contact area of the connection terminal with the external terminal. It is considered that the above can also be suppressed.

On the other hand, as shown in FIG. 10, in the conventional terminal material, zinc element (solid black circle), which is a base material constituent element, is first added to the surface of the tin film where the etching time is about 0 minutes. (Open circle) can be confirmed that it exists. This is considered to be because zinc element diffused from the base material diffuses toward the tin film side and precipitates on the tin film surface to form zinc oxide having low conductivity. Furthermore, conventionally, a large amount of a copper element (open square) together with a tin element (x mark) is present in the tin film between the etching time of 0 minute and about 18 minutes to the boundary between the tin film and the base material, that is, in the tin film. It is confirmed that it is. This is considered to be due to the fact that a large amount of copper diffuses from the base material into the tin film, forming an alloy having high hardness with copper and tin. As described above, in the connection terminal material of the conventional example, since the diffusion of the base material constituent elements is remarkably generated, the material is subjected to the heat treatment (FIG. 1).
Comparing each contact resistance value of 2) with that before heat treatment (FIG. 11),
The variation is large, and the resistance value is increasing.
As a result, when the conventional terminal material is used as the connection terminal of the fuse, the current value and the voltage value of the current flowing in the fuse fluctuate, and a large amount of heat is generated in the contact area of the connection terminal with the external terminal. It is thought that.

The change in the contact resistance of the connection terminal material according to the embodiment (FIGS. 8 and 9) is the same as that of the conventional example (FIG. 1).
1 and FIG. 12), the contact resistance is generally lower,
From this point as well, it can be seen that the terminal materials according to the examples have excellent reliability. Further, in the terminal material of the embodiment,
While almost no variation was observed, the conventional terminal material showed many variations, indicating that the quality of the terminal materials of Examples was stable.

[0043]

As described above, according to the fuse of the present invention, since the tin oxide film having a dense structure is formed between the base material and the tin film in the connection terminal, the use environment temperature can be increased. By the heat generated from the fusing part, the diffusion of the base metal constituent elements to the tin film side can be suppressed, the contact resistance of the connection terminal decreases, and the fluctuation of the current value and voltage value of the current flowing in the fuse can be prevented. In addition to being excellent in reliability, it is possible to obtain the effect that the generation of heat can be suppressed, and the fusing of the fusing portion at a rated electric capacity or less can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a fuse according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a sputtering apparatus for manufacturing a material for connection terminals of a fuse according to the first embodiment.

FIG. 3 is an enlarged sectional view of a main part showing the connection terminal material of the first embodiment.

FIG. 4 is a configuration diagram showing an ion beam mixing apparatus for producing a material for a connection terminal of a fuse according to a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a main part showing a material for connection terminals of the fuse of the second embodiment.

FIG. 6 is an enlarged sectional view of a main part showing connection terminals of a fuse according to a third embodiment of the present invention.

FIG. 7 shows X after heat treatment of the connection terminal material according to the embodiment.
It is a graph which shows the element distribution by PS.

FIG. 8 is a graph showing a change in contact resistance before heat treatment of a connection terminal material based on an example.

FIG. 9 is a graph showing a change in contact resistance after heat treatment of a connection terminal material based on an example.

FIG. 10 is a graph showing element distribution by XPS after heat treatment of a connection terminal material based on a conventional example.

FIG. 11 is a graph showing a change in contact resistance before heat treatment of a connection material based on a conventional example.

FIG. 12 is a graph showing a change in contact resistance after heat treatment of a connection terminal material based on a conventional example.

[Explanation of symbols]

 11, 31, 51 Base material 12, 32a, 32b, 52 Tin oxide film 13, 33a, 33b, 53 Tin film 100 Fuse 110, 210 Connection terminal 120 Fusing portion

Claims (1)

(57) [Scope of request for utility model registration] 1. A connection member having a tin film formed on a surface of a base material made of copper, a copper-based alloy, zinc, or a zinc-based alloy, and a conductive fusing portion bridged between the two terminals. Wherein each connection terminal is connected to an external terminal, wherein a tin oxide film is formed between a base material of the connection terminal and the tin film.