JP4573695B2 - Micromachine switch - Google Patents

Description

  The present invention belongs to a technical field of a micromachine that realizes an extremely fine mechanical mechanism using a semiconductor microfabrication technology, and particularly relates to a micromachine switch that controls switching between conduction / non-conduction of a signal line extending on a substrate. is there.

  As shown in FIGS. 8 and 9, this type of micromachine switch is configured by bringing a working electrode (80) into contact with or separating from a signal line (20) formed on the surface of a glass substrate (10). In this case, the conduction / non-conduction of the signal line (20) is controlled (see Patent Document 1).

The micromachine switch includes a pair of left and right silicon support portions (50) and (50) provided on both sides of the signal line (20) on the substrate (10), and the support portions (50) and (50). A pair of left and right silicon arms (70) and (70) extending in a direction approaching each other, and a pair of left and right silicon upper electrodes (40) provided at the distal ends of the arms (70) and (70) ( 40) and an insulating member (60a) laid across the back surfaces of both upper electrodes (40) and (40), and a silicon reinforcing portion (30) at the center of the surface of the insulating member (60a). ) And the working electrode (80) is formed at the center of the back surface of the insulating member (60a) so as to face the disconnection portion of the signal line (20).
On the other hand, a pair of left and right lower electrodes (90) and (90) are formed on the surface of the substrate (10) at positions facing the pair of left and right upper electrodes (40) and (40).

In the micromachine switch, by generating an electrostatic force between the upper electrodes (40) (40) and the lower electrodes (90) (90), as shown in FIG. 10, a pair of left and right arms (70) (70) ) Is elastically deformed, and the working electrode (80) comes into contact with the signal line (20). Further, by eliminating the electrostatic force, the first arm portions (70) (70) are elastically restored, and the working electrode (80) is separated from the signal line (20).
Japanese Patent No. 3538109

However, in the micromachine switch shown in FIG. 8, the pair of left and right arms (70) and (70) and the insulating members (60a) and (60a) are arranged in a straight line, so that they are orthogonal to the signal line (20). The width W ′ in the direction of the movement increases, causing not only the problem of interference with adjacent circuit parts (not shown) on the substrate (10), but also the arms (70) (70) Since the fixed beam is configured, the spring constant involved in the switch on / off operation is large. As a result, the internal stress when elastically deformed from the switch-off state shown in FIG. 9 to the switch-on state shown in FIG. 10 must be increased, and a large electrostatic force is required to overcome the internal stress. There is a problem that a large control voltage is required.
Furthermore, severe restrictions on the process were imposed such that the internal stress existing in the pair of arm portions (70) (70) and the insulating members (60a) (60a) is controlled to be small.

  Accordingly, an object of the present invention is to provide a micromachine switch that has a small width in the direction orthogonal to the signal line, can reduce the control voltage for switching on / off, and can further facilitate the process. is there.

  The micromachine switch according to the present invention switches and controls conduction / non-conduction of the signal line (2) by moving the working electrode (8) close to and away from the signal line (2) extending on the substrate (1). A support portion (5) disposed on the surface of the substrate (1), and a position protruding from the support portion (5) and spaced from the surface of the substrate (1) along the substrate (1). A cantilevered first arm portion (7), an upper electrode (4) provided at the tip of the first arm portion (7), and a substrate (1) protruding from the upper electrode (4). ), A second arm portion (6a) extending along the substrate (1), a working electrode (8) provided at the tip of the second arm portion (6a), and a substrate (1). ) And a lower electrode (9) disposed opposite to the upper electrode (4), and a protruding direction of the first arm portion (7) and a protruding position of the second arm portion (6a). A corner whose direction is not straight Crossing at a degree.

In the micromachine switch of the present invention, the working electrode (8) approaches the signal line (2) by generating an electrostatic force between the upper electrode (4) and the lower electrode (9). On the other hand, the working electrode (8) is separated from the signal line (2) by the elastic return force of the first arm portion (7).
Here, since the projecting direction of the first arm portion (7) and the projecting direction of the second arm portion (6a) cross each other at an angle that is not a straight line, the direction perpendicular to the signal line (2) The width is smaller than the width in the configuration in which even the first arm portion (7) is arranged in a straight line as in the conventional micromachine switch.
Moreover, since the 1st arm part (7) is bent with respect to the 2nd arm part (6a), the front-end | tip part comprises the cantilever (one-end fixed beam) which can be displaced freely. Therefore, the elastic restoring force acting on the first arm portion (7) in the switch-on state is smaller than that in the case where the arm portion constitutes a double-supported beam as in the prior art, and for switching on / off. The control voltage can be saved.
Further, since the internal stresses of the first arm portion (7) and the second arm portion (6a) are naturally released, the influence of the internal stress is reduced.

In a specific configuration, the protruding direction of the first arm portion (7) is parallel to the signal line (2), and the protruding direction of the second arm portion (6a) is orthogonal to the signal line (2). .
As a result, the lateral width in the direction orthogonal to the signal line of the micromachine switch is minimized and the control voltage is minimized.

In a more specific configuration, the support portion (5), the first arm portion (7), the upper electrode (4), the second arm portion (6a), and the lower electrode (9) sandwich the signal line (2). A pair of second arms (6a) and (6a) are arranged in a line-symmetrical positional relationship on each side, and the pair of second arms (6a) and (6a) extend in a direction approaching each other, and each tip is connected to the working electrode (8) Yes.
Similarly in the specific configuration, the width in the direction orthogonal to the signal line (2) is such that the pair of upper electrodes (4) and (4) and second arm portions (6a) and (6a) arranged in a straight line. And a length equal to or slightly larger than the length of the working electrode (8).
Further, the pair of left and right first arm portions (7) and (7) are bent at an angle which is not in a straight line with respect to the pair of left and right second arm portions (6a) and (6a). A possible cantilever will be constructed. Therefore, the control voltage for switching on / off can be saved.
Further, since the internal stresses of the first arm portion (7) and the second arm portion (6a) are naturally released, the influence of the internal stress is reduced.

  According to the micromachine switch of the present invention, it is possible to reduce the width in the direction orthogonal to the signal line and to reduce the control voltage for switching on / off. Furthermore, process conditions are facilitated because the internal stress is released.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The basic configuration of the micromachine switch according to the present invention is the same as that of the conventional micromachine switch shown in FIG. 8, and, as shown in FIGS. A signal line (2) is formed, and a DC signal or a high-frequency signal up to several hundred GHz band flows through the signal line (2) when the switch is turned on.

  A pair of silicon support parts (5) and (5) are formed on both sides of the signal line (2), and a pair of left and right silicon parts are parallel to the signal line (2) from both support parts (5) and (5). The first arm portions (7) and (7) extend away from the substrate (1), and a pair of left and right silicon upper electrodes are provided at the distal ends of the first arm portions (7) and (7). (4) (4) is formed.

Further, an insulating member (6) is installed across both upper electrodes (4) and (4), and a pair of left and right extending by the insulating member (6) perpendicular to the signal line (2) and approaching each other. Second arm portions (6a) and (6a) are formed. A reinforcing portion (3) made of silicon is formed on the surface of the central portion of the insulating member (6), and on the back side thereof, a signal line (2) is opposed to the disconnection region of the signal line (2). A working electrode (8) to be in contact with 2) is formed.
On the other hand, a pair of left and right lower electrodes (9) and (9) are formed on the surface of the substrate (1) so as to face the pair of left and right upper electrodes (4) and (4).

  The above micromachine switch is different from the conventional micromachine switch only in that the first arm portion (7) and the second arm portion (6a) are orthogonal to each other. It can be easily manufactured through a manufacturing process.

  In the micromachine switch of the present invention, by generating an electrostatic force between the upper electrode (4) (4) and the lower electrode (9) (9), a pair of left and right as shown in FIGS. The first arm portions (7) and (7) are elastically deformed so that the working electrode (8) contacts the signal line (2), and the signal line (2) is in a conductive state, that is, switched on. When the electrostatic force disappears, both the first arm portions (7) and (7) are elastically restored as shown in FIGS. 2, 3 and 4, and the working electrode (8) is separated from the signal line (2). The signal line (2) is non-conductive, that is, switched off.

  Here, since the projecting direction of the first arm portions (7) and (7) and the projecting direction of the second arm portion (6a) cross each other at an angle of 90 degrees, as shown in FIG. The width W in the direction perpendicular to the signal line (2) is such that a pair of left and right upper electrodes (4), (4), a pair of left and right second arms (6a) (6a) and a reinforcing part ( 3) The width of the conventional micromachine switch in which the length is equal to the length (for example, 600 μm), and the pair of support portions (5) (5) and the first arm portions (7) (7) are arranged in a straight line Than would be much smaller.

  The width V in the direction along the signal line (2) of the micromachine switch is such that the support part (5), the first arm part (7) and the upper electrode (4) arranged on a straight line parallel to the signal line (2). ) (E.g., 550 μm), but the width V is a problem in relation to other circuit parts to be provided on both sides of the signal line (2). Rather, the narrowing of the width W in the direction perpendicular to the signal line (2) effectively avoids interference with other circuit portions that are arranged on both sides of the signal line (2).

In the micromachine switch of the present invention, the first arm portion (7) is bent at an angle of 90 degrees with respect to the second arm portion (6a). A cantilever having a freely displaceable tip is formed. Therefore, the spring constant involved in the on / off operation of the micromachine switch is small. As a result, the elastic restoring force acting on the first arm portion (7) in the switch-on state is much smaller than that of a conventional micromachine switch in which the arm portion constitutes a double-supported beam. Therefore, the control voltage when the working electrode (8) is displaced by 3 μm can be reduced to about 20V, which is much less than the conventional several tens of volts.
Further, since the internal stresses of the first arm portion (7) and the second arm portion (6a) are naturally released, the influence of the internal stress is reduced.

  Furthermore, in the micromachine switch of the present invention described above, a switch comprising a support part (5), a first arm part (7), an upper electrode (4) and a second arm part (6a) on both sides of the signal line (2). Since the function part is provided and the second arm parts (6a) and (6a) are connected to each other by the reinforcing part (3), the switch function part is provided only on one side of the signal line (2). Compared with the micromachine switch, the contact state of the working electrode (8) and the signal line (2) in the switch-on state is stabilized, and the operation reliability is increased.

In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, in the above-described embodiment, the micromachine switch is configured in which the working electrode (8) is brought into contact with the signal line (2) having a disconnection portion in the middle thereof to make the signal line (2) conductive. A so-called shunt type micromachine that blocks the passage of a high-frequency signal by forming a capacitive component between the signal line (2) and the contact electrode (8) by bringing the working electrode (8) close to the uncut portion of It is also possible to configure a switch.
Further, the second arm portions (6a) and (6a) may be made of metal or semiconductor other than the insulating member. At this time, although leakage increases at a high frequency of 40 GHz or higher, there is an advantage that the process becomes easy. Further, the substrate (1) may be made of an insulating material such as GaAs or ceramic other than glass.

It is a top view of the micromachine switch concerning the present invention. It is sectional drawing which follows the AA line of FIG. 1 at the time of switch-off. It is sectional drawing which follows the BB line of FIG. 1 at the time of switch-off. It is sectional drawing which follows the CC line | wire of FIG. 1 at the time of switch-off. It is sectional drawing which follows the AA line of FIG. 1 at the time of switch-on. It is sectional drawing which follows the BB line of FIG. 1 at the time of switch-on. It is sectional drawing which follows the CC line | wire of FIG. 1 at the time of switch-on. It is a top view of the conventional micromachine switch. It is sectional drawing which follows the DD line | wire of FIG. 8 at the time of switch-off. It is sectional drawing which follows the DD line | wire of FIG. 8 at the time of switch-on.

Explanation of symbols

(1) Board
(2) Signal line
(3) Reinforcement part
(4) Upper electrode
(5) Support part
(6) Insulating material
(7) First arm
(6a) Second arm
(8) Working electrode
(9) Lower electrode

Claims (4)

In the micromachine switch for controlling the conduction / non-conduction of the signal line (2) by moving the working electrode (8) close to and away from the signal line (2) extending on the substrate (1),
A support (5) disposed on the surface of the substrate (1);
A cantilevered first arm portion (7) extending along the substrate (1) at a position protruding from the support portion (5) and spaced from the surface of the substrate (1);
An upper electrode (4) provided at the tip of the first arm portion (7);
A second arm portion (6a) projecting from the upper electrode (4) and extending along the substrate (1) at a position spaced from the surface of the substrate (1);
A working electrode (8) provided on the lower surface of the tip of the second arm portion (6a);
A lower electrode (9) disposed opposite to the upper electrode (4) on the surface of the substrate (1);
The The protruding direction of the protruding direction and the second arm portion of the first arm portion (7) (6a), and intersect at an angle not straight,
The first arm portion (7) and the upper electrode (4) are formed as an integral body made of the same conductive material,
The first arm portion (7) is thinner than the upper electrode (4),
An insulating member (6) is disposed on the lower surface of the upper electrode (4).
The insulating member (6) and the second arm portion (6a) are formed as an integral body made of the same insulating material,
A micromachine switch characterized in that a reinforcing portion (3) is disposed on the top surface of the tip of the second arm portion (6a) .   The micromachine switch according to claim 1, wherein the projecting direction of the first arm portion (7) and the projecting direction of the second arm portion (6a) cross each other at an angle of 90 degrees or substantially 90 degrees.   The protruding direction of the first arm portion (7) is parallel to the signal line (2), and the protruding direction of the second arm portion (6a) is orthogonal to the signal line (2). The micromachine switch described in.   The support part (5), the first arm part (7), the upper electrode (4), the second arm part (6a), and the lower electrode (9) are arranged in pairs on both sides of the signal line (2). A pair of second arm portions (6a) (6a) are arranged in a symmetrical positional relationship, extend in a direction approaching each other, and each tip portion is connected to the working electrode (8). Item 4. The micromachine switch according to any one of Items 3 to 3.

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