JP2001210206A - Thermo switch and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermo switch that can perform a normal switching operation even with an inclined movable contact, and method of manufacturing the same. SOLUTION: The thermo switch includes a movable piece 1 with a movable end, and a stationary piece 6 with separated stationary contacts 7a, 7b. The movable piece 1 has a flexible region 2, a thin film 5 of a different thermal expansion deposited on the flexible region 2, and a movable contact 4 formed on the movable end. The flexible region 2 is flexed by a temperature variation so as to move the movable contact 4 to switch the stationary contacts 7a, 7b. The stationary contacts 7a, 7b are respectively provided on X-shaped structures 6a, 6b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoswitch,
In particular, the present invention relates to a micro thermoswitch formed on a semiconductor substrate.

[0002]

2. Description of the Related Art Microthermoswitches (hereinafter referred to as thermoswitches) are characterized in that they are small in size, have a high response speed, and can perform a switching operation in response to a minute temperature change. 4 to 6 show the structure of a conventional thermoswitch. The thermoswitch is largely composed of a movable piece 1 and a fixed piece 6. The movable piece 1 has a flexible region 2 formed on a semiconductor substrate (silicon or the like) so that one end can be displaced, and a movable element 3 is formed on a displaced portion. On the surface of the flexible region 2, a thin film 5 (such as an aluminum thin film or a nickel thin film) having a different thermal expansion coefficient from silicon is laminated. A movable contact 4 is formed on the lower surface of the movable element 3. Fixing piece 6
The fixed contacts 7a and 7b which are separated from each other (insulated) are formed on the surface of a glass substrate or a silicon substrate, and the movable contacts 4 come into contact with the fixed contacts 7a and 7b to fix the fixed contacts 7a and 7b. Switching operation is performed between the two. The movable piece 1 and the fixed piece 6 are joined by anodic bonding, covalent gold bonding, or the like.

Next, the switching operation will be described.
When the flexible region 2 is heated, the flexible region 2 bends due to a difference in thermal expansion between the flexible region 2 and the thin film 5, and the movable element 3 is displaced. Due to this displacement, the movable contact 4 formed on the lower surface of the movable element 3 comes into contact with both the fixed contacts 7a and 7b, and the fixed contacts 7a and 7b become conductive.
FIGS. 5 and 6 show the positional relationship between the movable contact 4 and the fixed contacts 7a and 7b. FIG. 5 is a top view of the fixing piece 6, and FIG. 6 is a sectional view of the fixing piece 6 in A and B in FIG.

[0004]

However, in the structure of the conventional fixed piece 6, when the movable contact 4 is lowered while maintaining the horizontal state, the movable contact 4 comes into contact with both the fixed contacts 7a and 7b to establish a conductive state. However, when the flexible region 2 is lowered so as to have an angle with respect to the horizontal direction due to a slight change or variation of the flexible region 2, that is, when the flexible region 2 is lowered in an inclined state as shown in the movable contact 4a in FIG. However, there is a problem that the fixed contact 7b contacts the fixed contact 7b but does not contact the fixed contact 7a, that is, it does not become a conductive state and a normal switching operation cannot be performed.

The present invention has been made in view of the above circumstances, and has as its object to provide a thermoswitch capable of performing a normal switching operation even when a movable contact has an inclination, and a method of manufacturing the same. It is in.

[0006]

In order to achieve the above object, according to the present invention, there is provided the invention having a flexible region which is flexible and one end of which is displaceably supported. A thin film having a different coefficient of thermal expansion is laminated in the region, and a movable piece having a movable contact at an end to be displaced, and a fixed piece having a fixed contact separated from each other are provided. In the thermoswitch for opening and closing the fixed contact, the movable contact is displaced by bending of the region, wherein the fixed contact is formed on a beam-like structure that can be individually bent.

According to a second aspect of the present invention, there is provided a method for manufacturing a thermoswitch according to the first aspect, wherein a metal thin film is deposited on a substrate, and an electrode material is formed on the surface of the metal thin film by pattern plating. Forming a fixed contact by removing the metal thin film in a portion other than a portion to form a fixed contact; and forming a beam-like structure by etching the substrate portion in the fixed contact forming portion. It is characterized by doing so.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thermoswitch according to an embodiment of the present invention and a method of manufacturing the same will be described with reference to FIGS.
It will be explained based on the following. In the substrate of the fixing piece 6, the upper main surface in the figure is referred to as an upper surface, and the lower main surface is referred to as a lower surface.

FIG. 1 is a top view of a fixing piece 6 of a thermoswitch according to an embodiment of the present invention, and FIG. 2 is a view showing A and B in FIG.
It is sectional drawing of the fixing piece 6 in FIG. In FIGS. 1 and 2, the movable contact 4 is additionally shown for explanation of the operation.

The fixed piece 6 has fixed contacts 7a and 7b which are separated and electrically insulated. Here, as shown in FIG. 1, by forming a gap 11 by etching or the like, the fixed contacts 7a and 7b are formed to have cantilever structures 6a and 6b. When the movable contact 4 descends with an inclination to the fixed piece 6 formed in this manner, the beam-like structure 6a or 6b on the fixed contact side which has come into contact with the movable contact 4 first among the fixed contacts 7a and 7b is bent. Thereby, the movable contact 4 can come into contact with both the fixed contacts 7a and 7b. In FIG. 2, one end of the movable contact 4 contacts the fixed contact 7b first, the beam-like structure 6b bends, and then the other end of the movable contact 4 contacts the fixed contact 7a, and the fixed contacts 7a, 7b The state becomes conductive.

Since the portions of the fixed contacts 7a and 7b are formed into the beam-like structures 6a and 6b as described above, even if the movable contact 4 descends with an inclination, the side that first contacts the movable contact 4 Of the fixed contact 7a or 7b of the movable contact 4
Can contact both fixed contacts 7a and 7b,
There is an effect that a normal switching operation can be performed.

FIG. 3 is a process chart showing a method for manufacturing the fixing piece 6 of the thermoswitch according to the embodiment of the present invention. A metal thin film 8 made of chromium, nickel, copper, or a multilayer film of these metals is formed on the upper surface of a substrate (fixed piece 6) made of glass or silicon by a vacuum deposition method or the like (a).
Next, a photoresist 9 is applied to the surface of the metal thin film 8, and only portions where the fixed contacts 7a and 7b are to be formed are removed by exposure and development processes to form an opening (b). Next, by electroplating, the opening of the photoresist 9 previously formed is
Electrode material such as gold-cobalt alloy, and fixed contact 7
The electrode portions to be a and 7b are formed. That is, pattern plating is performed (c). Next, the photoresist 9 is removed,
The metal thin film 8 is etched using the electrode portion formed in the previous step as a mask to form fixed electrodes 7a and 7b (d). Here, it is necessary to select an appropriate etchant depending on the type of the metal thin film 8. Next, a sandblasting resist 10 is laminated on the lower surface of the substrate (fixing piece 6), and a portion to be penetrated by the substrate (fixing piece 6) is removed by an exposure and development process to form an opening (e). Next, the substrate (fixing piece 6) at the opening is penetrated by sandblasting using an abrasive such as silicon carbide,
Finally, the sandblasting resist 10 is removed (f).

In this manner, the fixed piece 6 in which the portions of the fixed contacts 7a and 7b are formed into beam-like structures 6a and 6b can be formed.

[0014]

As described above, according to the first aspect of the present invention, the flexible region is supported so that one end thereof can be displaced and has a flexible region. Thin films having different expansion coefficients are stacked, and the movable region includes a movable piece having a movable contact at a displaceable end, and a fixed piece having a fixed contact separated from each other. In the thermoswitch for displacing the movable contact and opening and closing the fixed contact, the fixed contact is formed on a beam-like structure that can be individually bent. Therefore, even if the movable contact has an inclination, normal switching can be performed. A thermoswitch capable of performing an operation can be provided.

According to the second aspect of the present invention, the first aspect is provided.
As a method for manufacturing the thermoswitch described above, a metal thin film is deposited on a substrate, an electrode material is formed on the surface of the metal thin film by pattern plating, and the metal thin film in a portion other than the electrode material forming portion is removed to form a fixed contact. Forming the fixed contact and forming the fixed piece by beam etching the substrate portion of the fixed contact forming portion, so that the fixed contact portions are individually beam-shaped. There is an effect that a fixed piece having a structure can be formed.

[Brief description of the drawings]

FIG. 1 is a top view of a fixing piece of a thermoswitch showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a fixed piece of the thermoswitch showing the embodiment of the present invention.

FIG. 3 is a process diagram of a method for manufacturing a fixed piece of the thermoswitch according to the embodiment of the present invention.

FIG. 4 is a perspective view of a conventional thermoswitch.

FIG. 5 is a top view of a fixing piece of a conventional thermoswitch.

FIG. 6 is a cross-sectional view of a fixing piece of a conventional thermoswitch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Movable piece 2 Flexible area 3 Movable element 4 Movable contact 5 Thin film 6 Fixed piece 7 Fixed contact 8 Metal thin film

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G023 AA11 CA24 CA25 CA29 5G041 AA20 BB06 CA01 CA13 CE10 DA20 5G051 AC18 AC28

Claims (2)

[Claims] 1. A flexible region having a flexible region, one end of which is supported in a displaceable manner, thin films having different thermal expansion coefficients are laminated on the flexible region, and a movable contact is provided on the displaceable end. A movable switch comprising a movable piece and a fixed piece having fixed contacts separated from each other, wherein the flexible region is deflected by a temperature change to displace the movable contact, and a thermoswitch for opening and closing the fixed contact. A thermoswitch, wherein the fixed contacts are individually formed on a bendable beam-like structure. 2. A step of depositing a metal thin film on a substrate, forming an electrode material on the surface of the metal thin film by pattern plating, and removing a portion of the metal thin film other than the electrode material forming portion to form a fixed contact. 2. The method for manufacturing a thermoswitch according to claim 1, further comprising the step of: forming the fixed piece by etching the substrate portion of the fixed contact forming portion by an etching process. .