JP2007207498A - Mechanism device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism device capable of preventing malfunction of an upper electrode sticking to a lower electrode due to Coulomb force, by widening a gap between the both electrodes in a method other than thickening of a sacrifice layer. <P>SOLUTION: The device is provided with a substrate 101 formed of an insulating material, a lower electrode 103 formed on the substrate 101, and an upper electrode 102 arranged at an opposite position of the lower electrode 103 and equipped with a cantilevered beam structure part 104 having a magnetic body. An open end part of a box-like glass package 111 is mounted on and fixed to a peripheral edge of the substrate 101 to cover the upper electrode 102 and the lower electrode 103 with it 111, and has a magnet 112 mounted on a top part the glass package 111. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mechanism device having a cantilever structure, and more particularly to a device that prevents malfunction due to electrostatic resistance.

A conventional mechanical device, for example, as a micro-reed switch, includes an upper electrode and a lower electrode having a cantilever structure on a substrate, and is formed using a semiconductor process (photolithography method), an electrolytic plating method, and a wet etching technique. For example, a case where a sacrificial layer is removed by wet etching to form a gap will be described.
Such a conventional mechanism device includes a substrate, a lower electrode, and an upper electrode. The board is a so-called printed board in which a copper foil as a conductive material is stuck on an insulating board made of glass epoxy resin, and unnecessary portions of the copper foil are removed to form a wiring pattern.
The lower electrode has a configuration in which the entire surface of the nickel layer is covered with a conductive layer. Each conductive layer is formed by using a semiconductor process (photolithography method) and an electrolytic plating method, and the conductive layer is made of gold (contact material).

Here, since gold is resistant to corrosion, by covering the nickel layer with gold, oxidation of the nickel layer can be prevented, and also oxidation of the conductive layer itself can be prevented, preventing an increase in contact resistance. Therefore, the contact performance can be stabilized.
In addition, the material constituting the conductive layer is also required to protect the nickel layer from being eroded during the wet etching in the removal of the sacrificial layer in the final process of manufacturing the mechanical device. Also on this surface, gold having etching resistance against the etching solution (here, ferric chloride) used in the wet etching in the final process is used.

The upper electrode has a cantilever structure portion formed by using a photolithography method and an electrolytic plating method, and a magnetic body portion. The cantilever structure part is composed of a base part whose bottom surface is in contact with a copper foil and a beam part supported by the base part, and is composed of gold (contact material) which is a conductive material having etching resistance. ing. Here, by using gold as the contact material, the contact performance can be stabilized as described above.
In addition, since gold is a flexible material with low hardness, the cantilever structure is made of gold, so that when the beam of the cantilever structure is pulled toward the lower electrode by magnetic force, Therefore, it is possible to configure a mechanism device as a highly sensitive micro-reed switch (see, for example, Patent Document 1).
Japanese Unexamined Patent Publication No. 2003-311698 (first page, FIG. 1)

However, in the conventional mechanism device described above, the Coulomb force acts between the beam portion and the lower electrode of the cantilever structure portion in the upper electrode, and the gap formed between the beam portion and the lower electrode is very narrow as 5 μm. Therefore, there has been a problem that the contact is attracted at a voltage of about several volts by the Coulomb force, and malfunction occurs during the opening and closing of the contact.
In order to widen the contact gap formed between the upper electrode and the lower electrode having the cantilever structure, it is necessary to increase the thickness of the sacrificial layer, but wet etching is performed to form a thick sacrificial layer. Therefore, there is a problem that it takes a long time to form.

  A mechanism device according to the present invention includes a substrate formed of an insulating material, a lower electrode formed on the substrate, a cantilever formed on the substrate and disposed at a position facing the lower electrode, and having a magnetic material An upper electrode having a structure portion, and an opening end of a box-shaped package is attached and fixed to the periphery of the substrate, the upper electrode and the lower electrode are covered with the package, and a magnet is attached to the upper portion of the package It is what I did.

As described above, according to the present invention, a substrate formed of an insulating material, a lower electrode formed on the substrate, a substrate formed on the substrate, disposed at a position facing the lower electrode, and provided with a magnetic material. An upper electrode having a cantilever structure, and an opening end of a box-shaped package is attached and fixed to the periphery of the substrate, the upper electrode and the lower electrode are covered with the package, and the upper portion of the package is covered with the upper electrode. Since the magnet is attached, the magnetic body is magnetized by the magnetic field generated from the magnet and attracted to the magnet side, and the upper electrode having the magnetic body is deflected in the upper direction, so the gap between the upper electrode and the lower electrode is increased. The sacrificial layer can be widened by a method other than increasing the thickness, and the gap can be widened to prevent malfunction of the upper electrode sticking to the lower electrode due to Coulomb force. It has the effect of.
Further, since the gap between the upper electrode and the lower electrode is widened, there is an effect that the applied voltage applied to the upper electrode and the lower electrode can be set high when the mechanical device is used as a microswitch.

1 is a perspective view showing a configuration of a mechanism device according to an embodiment of the present invention, FIG. 2 is a perspective view showing a state of an upper electrode warped upward due to the magnetic field of the mechanism device, and FIG. FIG. 4 is a circuit diagram showing a measurement circuit for obtaining data on the relationship between the gap amount of the upper electrode and the applied voltage of the mechanism device. .
In FIG. 1, a mechanism device 100 according to an embodiment of the present invention includes a substrate 101, an upper electrode 102, and a lower electrode 103.
The substrate 101 is a so-called printed board in which a copper foil as a conductive material is attached on an insulating substrate made of glass epoxy resin, and unnecessary portions of the copper foil are removed to form a wiring pattern.

  The upper electrode 102 includes a cantilever structure portion 104 and a magnetic body 105 that are formed by using a photolithography method and an electrolytic plating method, respectively. The cantilever structure 104 includes a base 106 whose bottom surface is in contact with the copper foil of the substrate 101, and a beam 107 supported by the base 106. The magnetic body 105 has a configuration in which the entire surface of the nickel layer is covered with a conductive layer. This conductive layer is also made of gold (contact material) which is a conductive material having etching resistance.

  The lower electrode 102 has a configuration in which the entire surface of the nickel layer is covered with a conductive layer. Each conductive layer is formed by using a semiconductor process (photolithography method) and an electrolytic plating method, and the conductive layer is made of gold (contact material) which is a conductive material having etching resistance.

In the first embodiment, the following configuration is adopted as a method of forming a wide gap 110 between the upper electrode 102 and the lower electrode 103 so that the upper electrode 102 does not malfunction due to the Coulomb force of the mechanism device 100. Yes.
The mechanism device 100 shown in FIG. 2 is wet-etched and dried to form a gap 110 between the upper electrode 102 and the lower electrode 103, and then the opening end of the box-shaped glass package 111 on the periphery of the substrate 101 of the mechanism device 100. The upper electrode 102 and the lower electrode 103 are covered with a glass package 111, and a magnet 112 is attached to the upper portion of the glass package 111.

  With this configuration, the magnetic body 105 is magnetized by the magnetic field 120 generated from the magnet 112, the south pole is induced on the base side 105 a of the magnetic body 105, and the north pole is induced on the opposite end side 105 b. Since the magnetic body 105 is attracted by the magnet 112, the upper electrode 102 including the magnetic body 105 is always warped upward, so that the gap 110 between the upper electrode 102 and the lower electrode 103 can be widened. The gap can be widened by a method other than increasing the thickness of the sacrificial layer.

Next, the operation of the mechanism device 100 according to the embodiment of the present invention will be described with reference to FIG.
After a gap 110 is formed between the upper electrode 102 and the lower electrode 103 by a drying process after the etching process of the mechanism device 100, the mechanism device 100 is covered with the glass package 111, and a magnet 112 is provided on the glass package 111. As shown in FIG. 3, the upper electrode 102 is magnetized by the magnetic field 120 from the magnet 112 and is attracted in the upper direction (direction 123 to be attracted), so that the gap 110 between the upper electrode 102 and the lower electrode 103 is changed. More than the thickness of the sacrificial layer.

When the mechanism device 113 in which the gap 110 is formed more than the thickness of the sacrificial layer is used as a microswitch, an electromagnet 124 is installed immediately below the mechanism device 100 as shown in FIG. Applied to generate a magnetic field 125.
Accordingly, the magnetic body 105 formed on the upper electrode 102 of the mechanism device 100 is magnetized by making the magnetic field 125 generated in the electromagnet 124 sufficiently stronger than the magnetic field 120 of the magnet 119 provided on the upper portion of the glass package 111. The electrode 102 is attracted in the direction 128 of the lower electrode 103, and the upper electrode 102 contacts the lower electrode 103 and is switched on.

  When the application of voltage to the electromagnet 124 is stopped, the magnetic field disappears, and the magnetic attractive force between the upper electrode 102 and the lower electrode 103 disappears due to the disappearance of the magnetic field, and the stiffness of the upper electrode 102 and the upper portion of the glass package 11 are provided. Due to the magnetic field 120 of the magnet 112, the upper electrode 102 returns to its original position and becomes non-contact and is switched off.

As described above, according to the embodiment of the present invention, the mechanism device 100 is covered with the glass package 111, and the upper electrode 102 including the magnetic body 105 using the magnetic field 120 of the magnet 112 provided on the upper portion of the glass package 111. Can be formed in the upper direction, so that the gap 110 can be formed between the upper electrode 102 and the lower electrode 103 to be larger than the thickness of the sacrificial layer.
As a result, the Coulomb force acting between the upper electrode 102 and the lower electrode 103 is increased by increasing the contact gap 110, so that C = εS / d (c−capacitance {F}, ε = dielectric constant, S = area , D = distance between contacts), the capacitance is reduced, and the malfunction of the upper electrode 102 sticking to the lower electrode 103 by the Coulomb force can be prevented.

FIG. 5 shows a measurement circuit for obtaining data on the relationship between the gap amount of the upper electrode of the mechanical device and the applied voltage, and V is a voltage power source that outputs the output voltage by varying the output voltage and can know the output voltage. And it connects so that the voltage of the voltage power supply V may be applied to the upper electrode 103 and the lower electrode 102. Then, in the measurement circuit shown in FIG. 5, various voltages are applied to the upper electrode 103 and the lower electrode 102 by the voltage power source V, and a voltage drop occurs when the upper electrode 103 contacts the lower electrode 102. Since the voltage applied to 103 and the lower electrode 102 and the gap amount between the upper electrode 103 and the lower electrode 102 are known, the relationship between the various applied voltages and the gap amount is shown in the graph in FIG. It is a graph which shows the relationship between an electrode, gap amount, and an applied voltage.
As shown in the graph of FIG. 6, as in the embodiment of the present invention, the contact voltage between the upper electrode 102 and the lower electrode 103 is increased to, for example, 50 μm, so that the applied voltage, which was about several volts, is 75 V. Can be raised to a certain extent.

  In the above embodiment, the glass package 11 is used as a member covering the mechanism device 1. However, a resin package or a metal package may be used instead of the glass package. In this case, a copper foil is pasted on the substrate 101. Since it is attached, it may be attached via an insulating member.

The perspective view which shows the structure of the mechanism device which concerns on embodiment of this invention. The perspective view which shows the mode of the upper electrode which curved in the upper direction by the influence of the magnetic field of the mechanism device. The perspective view which shows a mode that an upper electrode contacts a lower electrode under the influence of the electromagnet of the mechanism device. The circuit diagram which shows the measurement circuit for obtaining the data of the relationship between the gap amount of the upper electrode of the mechanism device, and an applied voltage. The graph which shows the relationship between the gap amount of the upper electrode of the mechanism device, and applied voltage.

Explanation of symbols

100 mechanical device, 101 substrate, 102 upper electrode, 103 lower electrode, 104 cantilever structure, 105 magnetic body, 107 base, 108 beam, 110 gap, 111 glass package, 112 magnet.

Claims (2)

A substrate formed of an insulating material; a lower electrode formed on the substrate; and an upper electrode formed on the substrate and disposed at a position opposite to the lower electrode and having a cantilever structure having a magnetic material. In the mechanism device provided,
A mechanism device, wherein an opening end of a box-shaped package is attached and fixed to a peripheral edge of the substrate, the upper electrode and the lower electrode are covered with the package, and a magnet is attached to the upper portion of the package. The mechanism device according to claim 1, wherein the package is made of glass, synthetic resin, or metal.

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