JPH0622093B2 - Substrate type thermal fuse and resistor and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a substrate type thermal fuse / resistor and a method for manufacturing the same, and more specifically, it operates quickly by using an ultrathin alumina substrate. That is, the present invention relates to a substrate type thermal fuse / resistor which has a fast response speed and is small and thin, and a manufacturing method thereof.

[Prior Art] A substrate-type thermal fuse / resistor is used in an electric device in order to prevent the resistor in the electric device from damaging the electric device due to heat generated by overcurrent or abnormally generated heat. Although the conventional substrate-type thermal fuse / resistor is installed, a low-melting metal body is generally provided between electrodes provided on an insulating substrate, and a flux layer is provided on the metal body, and then a resin layer is formed on the entire surface. It is configured by combining a thermal fuse provided with a coating layer and a resistor.

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

Various types of substrate type thermal fuses / resistors have been developed. For example, in the specification of Japanese Utility Model Publication No. Sho 63-97207, a low melting point metal body and a film resistor are provided on one surface of an insulating substrate. There is described a substrate type thermal fuse / resistor in which a flux layer is provided on a low melting point metal body and an insulating layer is provided on the entire surface of one surface of the insulating substrate.

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 / resistor disclosed in the above specification, the insulating layer covering the low-melting-point metal body and the film resistor is made of resin, In particular, heat received from the outside is not sufficiently transmitted from the resin layer side, and therefore the main path through which the heat propagates to the low melting point metal body is the ceramic substrate side. However, this ceramic substrate also has a thickness of 0.3.
Since it is as thick as ~ 1.5 mm, it takes a long time for heat to propagate, and its response is slow, so that there is a problem that it is not possible to sufficiently cope with recent highly functional electric devices.

On the other hand, since the film resistor has a thick layer of resin, the heat generated from the resistor is not sufficiently dissipated, so that the heat generated causes the resistor to overheat, and the heat flows to the thermal fuse through the ceramic substrate. , Activate the thermal fuse. Therefore, there is a problem that the thermal fuse is melted due to the accumulation of heat that should be dissipated.

Further, when using a flux, since the resin layer having a flux resistance is provided, the resin layer has a double structure, so that not only is the thickness large and the heat transfer is insufficient, but it is also not possible to reduce the thickness. Moreover, since it is a resin layer, there is a problem in 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, the first object of the present invention is that the heat propagation path is not limited, and also the heat can be sufficiently dissipated, and the heat propagation path is short, and therefore the size and thickness of the response speed are excellent, Another object of the present invention is to provide a substrate type thermal fuse / resistor having excellent heat resistance and flame resistance.

A second object of the present invention is to provide a method of manufacturing a miniaturized and thin substrate type thermal fuse / resistor having excellent response speed, which 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. A substrate type thermal fuse having a pair of electrodes in which electrodes are connected by a low melting point metal body and a film resistor covered with a flux resistant insulating film in each hollow part formed by the removed part. A substrate type thermal fuse / resistor characterized in that, in the resistor, each of the three alumina substrates has a dense structure with a thickness of 0.1 mm to 0.2 mm.

2) A substrate type thermal fuse / resistor characterized in that the hollow portion having the low melting point metal body according to claim 1 is filled with a flux.

3) A substrate type thermal fuse / resistor characterized in that the hollow portion having the film resistor according to claim 1 has a flux resistant insulator.

4) A substrate type thermal fuse, characterized in that the hollow portion having the low melting point metal body according to claim 1 is filled with a flux, and the hollow portion having a film resistor has an insulating material having a flux resistance. -Resistor.

5) Three alumina substrates having a dense structure with a thickness of 0.1 mm to 0.2 mm are prepared, and a low melting point metal body and a film-shaped resistor as a circuit component are provided on the first alumina substrate among them. After forming an electrode substrate with an electrode having a body, then forming a flux layer around the low melting point metal body, and coating the film resistor with a flux-resistant insulating film At least a portion corresponding to these circuit components of the second alumina substrate is cut by a laser to form a frame substrate made of an alumina substrate having a cutout portion, and a lid substrate made of a third alumina substrate is further provided. The present invention is achieved by a method for manufacturing a substrate type thermal fuse / resistor, characterized in that the electrode substrate, the frame substrate and the lid substrate are bonded sequentially or simultaneously.

[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.

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

As the film-shaped resistor used in the present invention, a resistance paste is usually used, and for example, a mixture of metal oxide particles and glass frit is used. For printing the resistance paste, a raw film or thin film technique that is usually used in this technical field such as screen printing 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.

The substrate-type thermal fuse / resistor used in the present invention has at least one pair of electrodes formed on the alumina substrate having an ultra-thin and dense structure by using the above-described conductor forming technique, and then between the electrodes. It is formed by connecting a low-melting-point metal body, and subsequently, a film-shaped resistor is formed on this alumina substrate by using the above-mentioned film forming technique. 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, a heat resistant adhesive is used as the adhesive.

An epoxy adhesive or the like is preferable.

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 a substrate type thermal fuse / resistor of the present invention.

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

In FIGS. 1 and 2, as the electrode substrate 1, an alumina substrate 13 having a thickness of 0.2 mm, which is manufactured by a sol-gel method having good thermal conductivity, is used. It has electrodes 4 and 4, and lead terminals 5 and 5 are provided on these electrodes. This electrode is screen printed using a conductive paste. Then, a resistance paste is printed on one of the electrodes 5 using a screen printing method to form the film resistor 3. Further, the obtained film resistor is covered with a film-like insulator such as glass having flux resistance. (Inside the dotted line surrounding the film resistor of FIG. 1) The low melting point metal body 2 is welded between the electrodes obtained as described above.

An Ag—Cu alloy is used for the low melting point metal body 2, which operates as a fuse element, and is melted and cut at a so-called high temperature.

Next, after covering the low melting point metal body 2 with the flux 6, a frame substrate 12 made of an alumina substrate having a thickness of 0.2 mm is cut out by a laser, and the lid substrate 11 made of an alumina substrate is stacked on the frame substrate 12. Overlap. This frame substrate 12
Has frames 71 and 72, the low melting point metal body 2 in the frame 71, and the film resistor in the frame 72. Frame 71
A flux 6 (within a dotted line surrounding the low-melting metal body in FIG. 1) is filled inside to cover the low-melting metal body 2,
Alternatively, the flux 6 may be filled into the low melting point metal body 2 after the frame substrate 12 is provided on the frame substrate 12.

Then, the electrode substrate, the frame substrate and the lid substrate are adhered to each other by using low melting point glass as a heat resistant adhesive.

The substrate-type thermal fuse / resistor formed as described above is used to protect electronic components used in electrical equipment in general, such as protection of semiconductor elements, protection against power module explosion, and MOS-FET protection. Examples of protection include protection of other electronic components such as transistors.

[Effects of the Invention] As is clear from the above description, in the present invention, since the substrate type thermal fuse / resistor is an ultrathin alumina substrate, the heat transfer path is not limited. It is possible to obtain a substrate type thermal fuse / resistor which has a short heat transfer path and a large strength, and therefore is excellent in response speed, is small and thin, and is also 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 temperature fuse / resistor having excellent response speed can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a plan view of a substrate type thermal fuse / resistor of the present invention. FIG. 2 shows I-of the substrate type thermal fuse / resistor of FIG.
It is sectional drawing which shows the part cut | disconnected by 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 ... Membrane resistor 4, 4 ... Electrode 5, 5 ... Terminal 6 ... Flux 71, 72 ... Frame

Claims (5)

[Claims] 1. A stack of three alumina substrates,
The alumina substrate at the center is a frame substrate having a cutout portion,
A substrate type in which each hollow portion formed by this cutout portion has a pair of electrodes in which electrodes are connected by a low melting point metal body and a film resistor covered with a flux resistant insulating film In the thermal fuse / resistor, a substrate type thermal fuse / resistor characterized in that the three alumina substrates each have a dense structure with a thickness of 0.05 mm to 0.2 mm. 2. A substrate type thermal fuse / resistor characterized in that the hollow portion having the low melting point metal body according to claim 1 is filled with a flux. 3. A substrate type thermal fuse / resistor, wherein the hollow portion having the film resistor according to claim 1 has a flux resistant insulator. 4. A substrate characterized in that the hollow portion having the low melting point metal body according to claim 1 is filled with a flux, and the hollow portion having a film-shaped resistor has a flux-resistant insulator. Mold thermal fuse / resistor. 5. Three alumina substrates having a dense structure with a thickness of 0.05 mm to 0.2 mm are prepared, and a low melting metal body and a low melting point metal body as a circuit component are provided on the first alumina substrate of the three alumina substrates. An electrode substrate having a film resistor is provided to form an electrode substrate, and then a flux layer is formed around the low melting point metal member, and the film resistor is provided with a flux-resistant insulating film. After coating, at least portions corresponding to these circuit components of the second alumina substrate are cut by a laser to form a frame substrate made of the alumina substrate having a cutout portion, and a lid made of the third alumina substrate is further formed. A method of manufacturing a substrate type thermal fuse / resistor, which comprises providing a substrate and adhering these electrode substrate, frame substrate and lid substrate sequentially or simultaneously.