JP2005353333A - Microswitch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microswitch with low power consumption and high reliability in a state for holding a switch. <P>SOLUTION: Beams 5 for a latch lying at both the adjacent sides of a thin-film heater 6 has a thermal insulation structure, a vertically movable complex 4 moves downward by applying an electrostatic sucking voltage between an electrode layer 7 and a lower substrate electrode 8 under a state electrified to the thin-film heater 6. When power supply to the thin-film heater 6 is stopped after contacting of a lower surface contact electrode 2 on an upper portion and a substrate contact electrode 3 on a lower portion, operation for returning to an original state is generated in the complex 4 that has been extended by heating, and the switch will be held even in a state that the application of the electrostatic sucking voltage is stopped. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure of a microelectromechanical switch and a relay, and more particularly, a switch that operates using a micro-electro-mechanical system (MEMS) type external force, such as an electrostatic force or an electromagnetic force, and the like. The present invention relates to a relay device (structure).

  MEMS and other microdevice devices are being developed for a wide variety of applications in view of the benefits of offered size, cost, and reliability. Many diverse MEMS devices such as micro gears and micro motors have been manufactured. These MEMS devices are taking advantage of the advantages of water pressure applications where MEMS pumps and valves are used, and the reduction in size and weight. Recently, RF electrical switches in cell phones, signal routing devices, impedance matching, etc. Attention has also been focused on application to networks, and further to use in space equipment.

  Such switches that operate using MEMS static electricity are superior in electrical isolation performance compared to composite solid-state switches such as PIN diodes widely used in microwave and millimeter wave integrated circuits (MMICs). The switch “on” state and the “quality” of the switch in the switch “off” state have the same performance as the mechanical switch. As described above, for example, a micro electromechanical switch or a micro electrostatic switch having a size of 100 μm × 100 μm and a thickness of about 1 μm to 10 μm has been proposed as a device using MEMS technology and semiconductor technology. For example, a switch that functions from a direct current to an RF frequency (see Patent Document 1), a switch that can switch a high voltage using an electrostatic operating voltage (see Patent Document 2), and the like have been proposed.

JP-A-9-17300 JP-T-2003-503816

  The switch using static electricity as described above realizes a switch switching operation by operating a switch movable part using an electrostatic force when the switch is operated, and contacting an electrical contact. After that, in order to maintain the above-described switch operation, it is necessary to continue the electrostatic force application, and the power consumption for continuing the electrostatic force is a large amount of power consumption if there are a large number of switches, which increases the efficiency in system operation. It was bad. Furthermore, the electrostatic force (electrostatic voltage value) may change in the switch holding state, causing instability of the electrical connection state and poor contact of the electrical connection part due to the instability, generation of electromigration, etc. The cause of the decline in reliability cannot be hidden.

  The present invention has been made in view of the above problems, and an object thereof is to provide a micro switch with low power consumption and high reliability.

The micro switch according to claim 1 of the present invention for solving the above-described problems is
In a micro switch having a beam-shaped switch body configured such that one end is fixed and the other end is reciprocally movable by an external force.
The switch body includes means for expanding and contracting a part of the switch body, and the switch body is configured to maintain a deformed state due to expansion and contraction.

The micro switch according to claim 2 of the present invention for solving the above-described problems is
The switch body includes a heating element that is deformed by being expanded and contracted, and a portion to which the heating element is attached is thermally insulated from adjacent portions on both sides thereof.

The micro switch according to claim 3 of the present invention for solving the above-described problem is
The switch body includes a cooling element that is deformed by expansion and contraction, and a portion to which the cooling element is attached is thermally insulated from adjacent portions on both sides thereof.

The micro switch according to claim 4 of the present invention for solving the above-described problems is
The switch body is composed of a composite of a nitride film and an oxide film.

A signal path switching apparatus according to claim 5 of the present invention for solving the above-described problems is provided.
It is characterized by combining a plurality of micro switches.

  Since the present invention is configured as described above, the following effects can be obtained.

  Even in the state in which external force, for example, electrostatic force, electromagnetic force, or thermal deformation force is excluded, the switch switching direction can be held, and the electrode contact portion in the holding state is reduced in power consumption required for holding, A reliable electrical connection can be achieved.

  In addition, in the switch function, it is possible to provide a switch that can switch connection in two directions as well as ON-OFF switching.

  Furthermore, as a device that makes full use of MEMS technology and semiconductor technology, for example, it is a device that combines multiple micro switches with a size of 100 μm × 100 μm and a thickness of about 1 μm to 10 μm. Specific application destinations include, for example, mobile phone devices and various space equipment devices.

  Embodiments of a micro switch according to the present invention will be described in detail based on examples with reference to the drawings.

FIG. 1 is a diagram showing an example of an embodiment of a micro switch according to the present invention.
The micro switch of the present embodiment has a lower substrate electrode 8 and a lower substrate contact electrode 3 on a microelectronic substrate 101, and a thin film heater with a composite 4 on the upper side, one of which is a fixed portion and the other is vertically movable. 6, an electrode layer 7 is formed inside the composite, and an upper lower contact electrode 2 is provided on the surface of the composite. Further, in the composite 4, the latch beam 5 has a pin spring structure (the description will be described later). These composite structures are formed on the planar technology shown in FIG. 13, that is, on a silicon substrate for semiconductor. The film, the silicon substrate itself, and the formed film are etched to make full use of a technique for producing a function having a desired shape and performance.

  Here, the pin spring structure refers to a “structure in which a pin is semi-fixed by applying an external force to one of the pins by an action similar to a spring mechanism”. Further, when the latch beam 5 is manufactured by the planar technology, the shape in the normal state is, for example, an upward stress state or a downward stress state depending on stress setting conditions such as a film thickness at the time of manufacturing and temperature control at the time of film formation. You can also make it in advance.

  Here, the switch operation will be described in detail with reference to FIG. 2 illustrating the switch operation and FIG. 3 illustrating the time series operation of the energization presence / absence of the thin film heater 6, the presence / absence of electrostatic attraction voltage application, and the switch switching state. . When the thin film heater 6 is energized (state 1 → state 2), the composite 4 is elongated by the heat around the heater heated by the thin film heater (state 2). In that state, the action of the upward stress state or the downward stress state described above is eliminated. Further, the latch beams 5 present on both sides of the thin film heater 6 have a heat insulating structure (the composite is partially etched to form a hollow structure), and heat conduction to the adjacent parts is poor. The elongation of the composite due to heat hardly occurs. By applying an electrostatic attraction voltage (electrostatic force) between the electrode layer 7 and the lower substrate electrode 8 while the thin film heater 6 is energized, the vertically movable composite 4 moves downward, and the upper lower contact The electrode 2 and the lower substrate contact electrode 3 are in contact. (State 3)

  In this state, when energization to the thin film heater 6 is stopped (state 4), the composite 4 that has been extended by heating has a function of returning to the original state. At this time, since the latch beam 5 has a pin spring structure as described above, the composite 4 is semi-fixed in the moving direction attracted by the electrostatic attraction voltage. Even when the application of the electrostatic attraction voltage is stopped, the switch is held (state 5).

  Thereafter, by starting energization of the thin film heater 6, the composite 4 is again stretched by heating. At this time, since the latch beam 5 has a pin spring structure as described above, since the composite body 4 is not applied with an electrostatic attraction force, the switch function is opened by the force to return to the original state. And the state is maintained. (State 6)

  Here, a general procedure for forming a film on a silicon substrate by the above-described planar technology, processing the composite into a required shape, and selectively etching the silicon substrate will be briefly described with reference to FIG. To do.

  In FIG. 13, first, a nitride film is formed on a silicon substrate, and the formed nitride film is etched by photolithography (FIG. 13-1). Next, an oxide film is similarly formed and etched (FIG. 13-2). Further thereon, a polycrystalline silicon film is formed and etched (FIG. 13-3), and processed as a composite containing necessary electrode materials (FIG. 13-6). After the fabrication of the composite body, the electrode portion for interface with the outside is formed and processed (FIG. 13-7), and finally the portion of the latch beam 5 which is a key in the present invention by selective etching of the silicon substrate itself. Is completed (removal of unnecessary silicon substrate portion). (Fig. 13-8)

  As described above, even when the electrostatic force is eliminated, the switch switching direction can be maintained, and the power consumption necessary for the holding can be reduced, and the electrode contact portion in the holding state can be reliably connected. There is an effect of state.

FIG. 4 is a diagram showing another example of the embodiment of the micro switch according to the present invention.
In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The minute switch of the present embodiment is that the starting force for moving the composite 4 up and down is an electromagnetic force. That is, the microelectronic substrate 101 has a lower substrate electrode 10 made of a magnetic material and a lower substrate contact electrode 3, on the upper part of which is a composite 4 in which one is a fixed portion and the other is vertically movable. A heater 6 and a thin film electromagnetic coil 9 are formed inside the composite, and an upper lower contact electrode 2 is provided on the composite surface.

  When the thin film heater 6 is energized, the composite 4 is stretched by the heat around the heater heated by the thin film heater. Further, the latching beams 5 existing on both sides of the thin film heater 6 have a heat insulating structure, and heat conduction is poor in the adjacent portions, so that the composite is not easily stretched by heat. By applying a voltage to the thin-film electromagnetic coil 9 while the thin-film heater 6 is energized, an electromagnetic attraction action is generated between the thin-film electromagnetic coil 9 and the lower substrate electrode 10 made of a magnetic material, and is movable up and down. The composite 4 moves downward, and the upper lower surface contact electrode 2 and the lower substrate contact electrode 3 come into contact with each other.

  Thereafter, by starting energization of the thin film heater 6, the composite 4 is again stretched by heating. At this time, since the latch beam 5 has a pin spring structure as described above, since the composite body 4 is not applied with electromagnetic force, the switch function is opened by the force to return to the original state. That state is maintained.

  FIG. 5 shows a diagram illustrating the above switch operation. Moreover, the figure which showed the time series operation | movement of the presence or absence of electricity supply to the thin film heater 6, the thin film electromagnetic coil voltage application state, and the switch switching state was shown in FIG.

  As described above, the switch switching direction can be maintained even when the electromagnetic force is eliminated, and the power consumption necessary for the holding is reduced, and the electrode contact portion in the holding state is reliably connected electrically. There is an effect of state.

  Further, the present invention is effective when applied to an environment using an IC that is weak against static electricity, for example, in an environment where electrostatic force cannot be used, as described in the first embodiment.

FIG. 7 is a diagram showing another example of the embodiment of the micro switch according to the present invention.
In the present embodiment, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The minute switch of the present embodiment is that the starting force for moving the composite 4 up and down uses an alloy material (hereinafter referred to as “bimetal”) having a different thermal expansion coefficient. That is, the lower substrate contact electrode 3 is provided on the microelectronic substrate 101, and on the upper part is a composite 4 in which one is a fixed portion and the other is movable up and down, a thin film heater 6, a bimetal upper layer 11, a bimetal lower layer 12, A bimetal upper layer thin film heater 110 (not shown) and a bimetal lower layer thin film heater 120 (not shown) are formed inside the composite, and an upper lower surface contact electrode 2 is provided on the surface of the composite. .

  When the thin film heater 6 is energized, the composite 4 is stretched by the heat around the heater heated by the thin film heater. Further, the latching beams 5 existing on both sides of the thin film heater 6 have a heat insulating structure, and heat conduction is poor in the adjacent portions, so that the composite is not easily stretched by heat. By energizing the thin film heater 110 for the bimetal upper layer while energized to the thin film heater 6, the bimetal upper layer 11 causes a downward deformation, and as a result, the vertically movable composite 4 moves downward, The upper lower surface contact electrode 2 and the lower substrate contact electrode 3 are in contact with each other. Similarly, by stopping energization of the bimetal upper layer thin film heater 110, the bimetal upper layer 11 causes an upward deformation, and as a result, the vertically movable composite 4 moves upward, and the upper lower surface contact electrode 2 and the lower substrate contact electrode 3 are in an open state.

  A diagram illustrating the above switch operation is shown in FIG. Further, FIG. 9 shows a time series operation of whether or not the thin film heater 6 is energized, whether or not a voltage is applied to the bimetal thin film heater, and the switch switching state.

  The functions of the bimetal lower layer 12 and the thin film heater 120 for the bimetal lower layer will be described later.

  As described above, it is possible to maintain the switch switching direction even when the thermal deformation force is eliminated, and to reduce the power consumption necessary for the holding and to ensure the electrical contact with the electrode contact portion in the holding state. This has the effect of connecting.

  In addition, it is effective in application to the environment described in the first and second embodiments in which the electrostatic force and the electromagnetic force cannot be used, for example, a device using an IC that is weak against static electricity and a strong magnetic field device such as a motor Play.

FIG. 10 is a diagram showing another example of the embodiment of the micro switch according to the present invention.
This embodiment is a content obtained by partially improving the content described in the first embodiment, and is an improved content with two switch switching functions. The same components as those in the first embodiment, the second embodiment, and the third embodiment are denoted by the same reference numerals, and redundant description is omitted.

  When the thin film heater 6 is energized, the heater peripheral portion heated by the thin film heater is stretched in the composite 4 due to the heat. Further, the latch beam 5 existing on both sides of the thin film heater 6 has a heat insulating structure, and heat conduction is poor in the adjacent portions, and therefore, the composite is not easily stretched by heat. By applying an electrostatic attraction voltage between the electrode layer 7 and the lower substrate electrode 8 while the thin film heater 6 is energized, the vertically movable composite 4 moves downward, and the upper lower contact electrode 2 and the lower electrode As described in the first embodiment, even when the substrate contact electrode 3 is in contact and the energization to the thin film heater 6 is stopped, the state where the upper lower surface contact electrode 2 and the lower substrate contact electrode 3 are in contact by the pin spring structure continues. It is. Next, when the thin film heater 6 is energized, the latching beam 5 moves up and down in the normal state when the normal state is upward due to the manufacturing stress condition, and the upper upper contact electrode 20 and the upper upper contact electrode 20 are moved upward. The substrate contact electrode 30 contacts.

  Thus, it has a two-system switch function.

  As described above, not only ON-OFF switching but also connection switching effect in two directions is achieved.

FIG. 11 is a diagram showing another example of the embodiment of the micro switch according to the present invention.
The present embodiment is a content obtained by partially improving the content described in the second embodiment, and is an improved content in which the switch switching function has two systems. The same components as those in the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment are denoted by the same reference numerals, and redundant description is omitted.

  When the thin film heater 6 is energized, the heater peripheral portion heated by the thin film heater is stretched in the composite 4 due to the heat. Further, the latch beam 5 existing on both sides of the thin film heater 6 has a heat insulating structure, and heat conduction is poor in the adjacent portions, and therefore, the composite is not easily stretched by heat. By applying a voltage to the thin-film electromagnetic coil 9 while the thin-film heater 6 is energized, an electromagnetic attraction phenomenon occurs between the thin-film electromagnetic coil 9 and the lower substrate electrode 10 made of a magnetic material, and is movable up and down. The composite 4 moves upward, the upper lower surface contact electrode 2 and the lower substrate contact electrode 3 come into contact with each other, and even if the energization to the thin film heater 6 is stopped, the upper lower surface contact electrode 2 and the lower substrate contact electrode are caused by the pin spring structure. As described in the second embodiment, the state in which 3 is in contact continues. Next, when the thin film heater 6 is energized, the latching beam 5 moves up and down in the normal state when the normal state is upward due to the manufacturing stress condition, and the upper upper contact electrode 20 and the upper upper contact electrode 20 are moved upward. The substrate contact electrode 30 contacts.

  Thus, it has a two-system switch function.

  As described above, not only ON-OFF switching but also connection switching effect in two directions is achieved.

FIG. 12 is a diagram showing another example of the embodiment of the micro switch according to the present invention.
This embodiment is a content obtained by partially improving the content described in the above-described third embodiment, and is an improved content in which the switch switching function has two systems. The same components as those in the first embodiment, the second embodiment, the third embodiment, the fourth embodiment, and the fifth embodiment are denoted by the same reference numerals, and a duplicate description is omitted.

  When the thin film heater 6 is energized, the heater peripheral portion heated by the thin film heater is stretched in the composite 4 due to the heat. Further, the latch beam 5 existing on both sides of the thin film heater 6 has a heat insulating structure, and heat conduction is poor in the adjacent portions, and therefore, the composite is not easily stretched by heat. By energizing the thin film heater 110 for the bimetal upper layer while energized to the thin film heater 6, the bimetal upper layer 11 causes a downward deformation, and as a result, the vertically movable composite 4 moves downward, The upper lower surface contact electrode 2 and the lower substrate contact electrode 3 are in contact with each other. Similarly, by stopping energization to the bimetal upper layer thin film heater 110, the bimetal upper layer 11 causes upward deformation, and as a result, the vertically movable composite 4 moves upward, and the upper lower surface contact electrode 2 and the lower substrate contact electrode 3 are in an open state.

  Similarly, when the thin film heater 6 is energized, by energizing the thin film heater 120 for the bimetal lower layer, the bimetal lower layer 12 is deformed upward, and as a result, the vertically movable composite 4 is moved upward. The upper upper surface contact electrode 20 and the upper substrate contact electrode 30 come into contact with each other. Similarly, by stopping energization of the thin film heater 120 for the bimetal lower layer, the bimetal lower layer 12 is deformed downward. As a result, the vertically movable composite 4 moves downward, and the upper upper surface contact electrode 20 and the upper substrate contact electrode 30 are in an open state.

  In addition, the operation direction of the bimetal upper layer 11 described above may be an upward direction opposite to the aforementioned direction by energizing the thin film heater 110 for the bimetal upper layer. Similarly, the operation direction of the bimetal lower layer 12 may be a downward direction opposite to the aforementioned direction by energizing the thin film heater 120 for the bimetal lower layer.

  As described above, not only ON-OFF switching but also connection switching effect in two directions is achieved.

  Any element that generates electromagnetic force may be used instead of the thin-film electromagnetic coil 9 described in the second and fifth embodiments, and therefore, a general magnetic material element can be used.

  Further downsizing and high reliability effect are also achieved.

  The signal path switching device described in the first to seventh embodiments combined with an electronic component including a plurality of micro switches can be used for a device that is required to be reduced in size and weight.

  As described above, there are also small and highly reliable device effects.

  It is being developed for a wide variety of applications in terms of advantages such as size, cost, and reliability. Taking advantage of the reduction in size and weight, application to RF electrical switches in cellular phones, signal routing devices, impedance matching networks, and use in space-oriented equipment is also attracting attention.

It is a figure which shows the structure of the micro switch using the electrostatic force which concerns on this invention. It is a figure which shows operation | movement of the micro switch using the electrostatic force which concerns on this invention. It is a figure which shows the switch state transition of the micro switch using the electrostatic force which concerns on this invention. It is a figure which shows the structure of the micro switch using the electromagnetic force which concerns on this invention. It is a figure which shows operation | movement of the micro switch using the electromagnetic force which concerns on this invention. It is a figure which shows the switch state transition of the micro switch using the electromagnetic force which concerns on this invention. It is a figure which shows the structure of the micro switch using the thermal deformation force which concerns on this invention. It is a figure which shows operation | movement of the micro switch using the thermal deformation force which concerns on this invention. It is a figure which shows the switch state transition of the micro switch using the thermal deformation force which concerns on this invention. It is a figure which shows the structure of the 2 system | strain microswitch using the electrostatic force which concerns on this invention. It is a figure which shows the structure of the 2 system | strain microswitch using the electromagnetic force which concerns on this invention. It is a figure which shows the structure of the 2 system | strain microswitch using the thermal deformation force which concerns on this invention. It is a figure which shows an example of the manufacturing process using the planar technique which concerns on this invention. It is a figure which shows an example of the bird's-eye view of the micro switch concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Minute switch 2 Upper lower surface contact electrode 3 Lower board contact electrode 4 Composite 5 Latching beam 6 Thin film heater 7 Electrode layer 8 Lower board electrode 9 Thin film electromagnetic coil 10 Lower board electrode (magnetic material)
11 Bimetal upper layer 12 Bimetal lower layer 20 Upper upper surface contact electrode 30 Upper substrate contact electrode 101 Micro electronic substrate 102 Micro electronic substrate 110 Bimetal upper layer heater 120 Bimetal lower layer heater 150 Support plate

Claims (5)

In a micro switch having a beam-shaped switch body configured such that one end is fixed and the other end is reciprocally movable by an external force.
The switch body includes means for expanding and contracting a part of the switch body, and the switch body is configured to maintain a deformed state due to expansion and contraction. switch. In the micro switch according to claim 1,
The switch body includes a heating element that is deformed by expansion and contraction, and a portion to which the heating element is attached is thermally insulated from adjacent portions on both sides thereof. switch. In the micro switch according to claim 1,
The switch body includes a cooling element that is deformed by expansion and contraction, and a portion to which the cooling element is attached is thermally insulated from adjacent portions on both sides thereof. switch. In the micro switch according to claim 1,
The switch body is composed of a complex of a nitride film and an oxide film, and is a micro switch.   6. A signal path switching device comprising a plurality of the micro switches according to claim 1 combined.

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