JPH0622092B2 - Substrate type thermal fuse and manufacturing method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate type thermal fuse and a method of manufacturing the same, and more particularly, it uses a super-thin alumina substrate for quick operation, that is, response speed. The present invention relates to a substrate-type thermal fuse that is fast, compact and thin, and a method for manufacturing the same.

[Prior Art] A substrate type thermal fuse is installed in an electric device in order to prevent damage to the electric device due to heat generated by overcurrent of the electric device or abnormally generated heat. In the conventional substrate type thermal fuse, a low melting point metal body is generally provided between electrodes provided on an insulating substrate, a flux layer is provided thereon, and then a resin coating layer is provided on the entire surface.

In this substrate type thermal fuse, the flux layer is melted by the heat generated by the electric device, and when the device is overheated, the low melting point metal body is melted by the heat.

Various types of such substrate type thermal fuses have been developed. For example, in the specification of Japanese Utility Model Laid-Open No. 63-106040,
In a thermal fuse in which a fuse element made of a low melting point metal is provided on a ceramic substrate and a cured resin layer is provided thereon, the operating speed of the substrate type thermal fuse can be improved by setting the thickness of the ceramic substrate to 0.3 to 1.5 mm. It is described that the above can be improved.

The resin layer provided on the flux has a double structure, and the resin on the side in contact with the flux is made of a material having corrosion resistance to the flux.

[Problems to be Solved by the Invention] However, in the substrate-type thermal fuse disclosed in the above specification, since the insulating layer covering the low-melting-point metal body is made of resin, heat received from the outside is The heat is not sufficiently transferred from the resin layer, and therefore the main path through which heat is transferred to the low melting point metal body is the ceramic substrate side. However, since this ceramic substrate also has a large thickness of 0.3 to 1.5 mm, it takes a long time to propagate heat and its response becomes slow, so that it cannot be sufficiently applied to recent highly functional electric devices. There is a problem.

In addition, when the resin layer provided on the flux has a double structure, there is a problem that not only the thickness is thick and the heat transfer is insufficient but also the thickness cannot be reduced. There is a problem with heat resistance and flame resistance.

Therefore, in view of the above problems, the present inventor has conducted various researches, and as a result of using a super-thin alumina substrate and a manufacturing method using the same, the above problems can be solved. Heading, the present invention was invented based on this.

Therefore, a first object of the present invention is that the heat propagation path is not limited, and the heat propagation path is short, and therefore the response speed is excellent, and the size and thickness are reduced, and the heat resistance and the flame resistance are excellent. Another object is to provide a substrate type thermal fuse.

A second object of the present invention is to provide a method of manufacturing a miniaturized and thin substrate type thermal fuse which has an excellent response speed and can be easily formed by using an alumina substrate.

[Means for Solving the Problems] Therefore, the above-mentioned objects of the present invention are as follows: 1) It is composed of three stacked alumina substrates, and the central alumina substrate is a frame substrate having a cutout portion. In a substrate type thermal fuse having a pair of electrodes in which the electrodes are connected by a low melting point metal body in the hollow portion formed by the removed portion, the three alumina substrates are both 0.05 m
A substrate-type thermal fuse having a thickness of m to 0.2 mm and a dense structure.

2) A substrate type thermal fuse, wherein the cutout portion according to claim 1 is filled with flux.

3) Prepare three alumina substrates having a dense structure with a thickness of 0.05 mm to 0.2 mm, and connect electrodes made by using the first alumina substrate among them with a low melting point metal body. Forming an electrode substrate having electrodes, and then cutting the second alumina substrate with a laser so as to form a cutout portion around the low melting point metal body to form a frame substrate having a cutout portion. A substrate characterized by being formed, stacking this frame substrate on the electrode substrate, further stacking a third alumina substrate on the frame substrate, and adhering these electrode substrate, frame substrate and lid substrate sequentially or simultaneously. This is achieved by a method of manufacturing a mold thermal fuse.

[Detailed Description of the Invention] Next, the present invention will be described more specifically.

In the present invention, "extremely thin" and "ultra-ultra-thin" mean a material that is much thinner than a substrate usually used in this technical field, has a thickness of 0.05 mm to 0.2 mm, and has high strength.

The substrate on which the electrode used in the present invention is formed is preferably an alumina substrate having an ultrathin and dense structure,
For example, it means an alumina ceramic produced by the sol-gel method, and the obtained alumina substrate has a thickness of
It includes a 96% alumina substrate and a 99% alumina substrate of 0.05 mm to 0.2 mm, preferably 0.1 mm to 0.2 mm.

The electrodes used in the present invention include metals usually used in this technical field such as copper, gold, silver, platinum, palladium, nickel and tungsten, and are appropriately selected according to the purpose of use.

In addition, these metals are formed by screen printing as a conductor paste, etching by a corrosive solution using an etching technique, or sputter etching, and an electrode forming technique such as metal vapor deposition.

A low melting point metal body is connected to the electrodes, and welding, soldering, or the like is used for this connection.

Further, as the low melting point metal body, a simple substance of silver, copper, tin, lead or the like or an alloy thereof is used.

The hollow part of the alumina substrate used in the present invention is formed by a method such as molding or laser cutting.
The shape of the hollow portion is also related to the shape of the low melting point metal body, but in general, any shape is used, preferably rectangular or circular, more preferably oval.

The hollow portion may or may not be filled with a flux, but it is preferable that the hollow portion is filled with a flux. In this case, preferable fluxes include rosin and active rosin. Resin flux containing rosin derivative, organic acid flux such as stearic acid, oleic acid, organic halogen compound such as aniline hydrochloride, inorganic acid flux such as acid such as hydrochloric acid and salt such as zinc chloride are used. However, resin-based and organic acid-based fluxes are preferable.

In the substrate type thermal fuse used in the present invention, at least one pair of electrodes is formed on the alumina substrate having an ultrathin and dense structure by using the above-mentioned conductor forming technique, and then the low melting point metal is provided between the electrodes. Formed by connecting the bodies. Next, a frame body is formed by removing a portion of another alumina substrate corresponding to the electrode portion. This is laminated on the substrate having the above electrode and bonded with an adhesive, and further a lid made of an alumina substrate having an ultrathin and dense structure for sealing is laminated and bonded thereon. In this case, as the adhesive,
A heat resistant adhesive is used.

Examples of preferable heat-resistant adhesives include inorganic adhesives such as glass, organic adhesives such as polyimide-based, polyamideimide-based, and polybenzimidazole-based adhesives.

For the adhesion, the alumina substrate, the frame and the lid may be sequentially adhered, or may be adhered simultaneously.

[Examples] Hereinafter, the present invention will be described more specifically with reference to examples, but this is one embodiment of the present invention, and the present invention is not limited to these examples.

FIG. 1 is a plan view showing the structure of the substrate type thermal fuse of the present invention.

FIG. 2 is a cross-sectional view showing a portion cut by II 'in FIG.

In FIGS. 1 and 2, the electrode substrate 1 has a thickness of 0.2, which is manufactured by the sol-ge method having good thermal conductivity.
mm alumina substrate 13 is used.
There is a pair of electrodes 3 and 3 on the top, and lead terminals 4 and 4 are provided on these electrodes. This electrode is screen printed using a conductive paste. The low melting point metal body 2 is welded between the electrodes thus obtained to form the electrode substrate 1. An Ag-Cu alloy is used for the low melting point metal body 2,
It operates as a fuse element and is melted and cut at a so-called high temperature. After coating the low melting point metal body 2 with the flux 6, an alumina substrate having a thickness of 0.2 mm is also cut out by a laser to form a frame 5, and a frame substrate 12 having this frame 5 is superposed on the frame substrate 12. A lid 11 made of an alumina substrate having a thickness of 0.2 mm is overlaid. The frame 5 of the frame substrate 12 is filled with a flux 6 (indicated by a dotted line in FIG. 1) so as to cover the low melting point metal body 2. However, in another method, the flux 6 is applied to the low melting point metal body 2. After the frame substrate 12 is positioned and provided, it may be filled therein.

Then, the electrode substrate, the frame substrate, and the lid substrate are bonded together by using low-melting glass as a heat-resistant adhesive.

The board-type thermal fuse formed as described above is used to protect electronic components used in electrical equipment in general,
Examples include protection of semiconductor devices, protection against power module explosions, protection of MOS-FETs, and protection of other electronic components such as transistors.

[Effects of the Invention] As apparent from the above description, in the present invention, since the substrate type thermal fuse uses the ultra-thin alumina substrate, the heat transfer path is not limited and the heat transfer is not limited. It is possible to obtain a substrate type thermal fuse having a short length and a large strength, a small size and a thin shape, which is excellent in response speed, and further excellent in heat resistance and flame resistance.

Further, since it is manufactured by using one kind of ultra-thin alumina substrate, it has an excellent effect that a miniaturized and thinned substrate type thermal fuse excellent in response speed can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a plan view of a substrate type thermal fuse of the present invention. FIG. 2 is a sectional view showing a portion of the substrate type thermal fuse of FIG. 1 cut by I-I '. Explanation of reference numerals 1 ... Electrode substrate 11 ... Ultra-thin alumina substrate (lid) 12 ... Frame substrate 13 ... Ultra-thin alumina substrate (supporting substrate) 2 ... Low melting point metal body (fuse element) 3 3 ... Electrode 4, 4 ... Terminal 5 ... Frame 6 ... Flux

Claims (3)

[Claims] 1. A stack of three alumina substrates,
The alumina substrate at the center is a frame substrate having a cutout portion,
In a substrate type thermal fuse having a pair of electrodes whose electrodes are connected by a low melting point metal body in a hollow portion formed by the cutout portion, both of the three alumina substrates are 0.05 mm to 0 mm. A substrate type thermal fuse having a thickness of 2 mm and a dense structure. 2. A substrate type thermal fuse, wherein the cutout portion according to claim 1 is filled with flux. 3. An alumina substrate having a dense structure with a thickness of 0.05 mm to 0.2 mm is prepared, and a low melting point metal is formed between electrodes formed by using the first alumina substrate among them. An electrode substrate having electrodes connected by a body is formed, and then a second alumina substrate is cut with a laser so as to form a cutout portion around the low melting point metal body and has a cutout portion. A frame substrate is formed, the frame substrate is stacked on the electrode substrate, a third alumina substrate is stacked on the frame substrate, and the electrode substrate, the frame substrate and the lid substrate are sequentially or simultaneously bonded. A method of manufacturing a substrate type thermal fuse.