JP2013114755A - Switch device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cantilever from being brought into contact with a ground line while realizing stable contact between a movable terminal and a signal line.SOLUTION: A switch device 1 includes: a base substrate 10; a movable portion 11; a signal line 12; and a pair of ground lines 131, 132. The movable portion 11 includes: first and second cantilevers 111, 112; a movable terminal 113; and first and second piezoelectric drive portions 114, 115. The signal line 12 faces the movable portion 113 at a first distance H1 and includes a fixing terminal 120 contactable with the movable terminal during deformation of the first cantilever due to the first piezoelectric drive portion. The pair of ground lines 131, 132 include line portions 130 facing the movable portion 11 at a second distance H2 larger than the first distance H1, and are arranged so as to sandwich the signal line 12.

Description

  The present invention relates to a switch device that is manufactured using, for example, a micro electro mechanical system (MEMS) and switches a high-frequency signal between a passing state and an open state (or a short-circuit state), and a manufacturing method thereof.

  2. Description of the Related Art In recent years, MEMS type RF switches are known as high-frequency signal switching devices manufactured using micromachine technology. This type of switch device typically includes an elastically deformable cantilever, a movable terminal provided on the cantilever, and a signal line (fixed terminal) facing the movable terminal. The switch device is configured to be able to switch between a state in which the movable terminal is in contact with the signal line by deformation of the cantilever and a state in which the movable terminal is separated from the signal line. Such a switch device has a structure in which a coplanar type line, a microstrip, or a strip line is provided because excellent transmission performance at a higher frequency is required. As the driving method for the movable terminal, an electrostatic attraction method, a piezoelectric driving method, and the like are known.

  For example, the following Patent Documents 1 and 2 describe a coplanar line structure in which fixed electrodes are arranged at equal distances on both sides of a signal line in a switch that drives a movable electrode by electrostatic attraction and electrically opens and closes the signal line. Has been. Patent Document 3 below describes a switching element in which a movable part is deformed by contraction of a piezoelectric film, and a movable contact part formed on the movable part is brought into contact with a fixed contact part. Further, Patent Document 4 below describes a coplanar line structure in which a pair of ground lines are arranged so as to sandwich the signal line in a MEMS switch in which the drive arm is brought into contact with the signal line by piezoelectrically driving the drive arm. ing.

JP 2000-113792 A JP 2009-277617 A JP 2005-293918 A JP 2009-266615 A

  In a switch device in which the movable terminal is brought into contact with the signal line by piezoelectric driving, the driving voltage of the piezoelectric material is set to be relatively high in order to realize a stable contact state between the movable terminal and the signal line. There are many. In this case, the signal line may be displaced in the pressing direction by the pressing force of the movable terminal. In a switch device having a coplanar line structure, the cantilever that supports the movable terminal comes into contact with the ground line that is disposed close to the signal line, which causes the ground line to be deformed or cause an electrical failure such as a short circuit. Further, there is a possibility that the piezoelectric body and the electrode formed on the cantilever are damaged due to a short circuit and the driving function is impaired.

  In view of the circumstances as described above, an object of the present invention is to provide a piezoelectric drive system having a coplanar type line structure capable of avoiding contact between a cantilever and a ground line while realizing stable contact between a movable terminal and a signal line. The switch device and its manufacturing method are provided.

In order to achieve the above object, a switch device according to an embodiment of the present invention includes a base substrate, a movable portion, a signal line, and a ground line.
The movable part includes a first cantilever, a movable terminal, and a first piezoelectric drive part. The first cantilever is elastically deformable and has a first end fixed to the base substrate. The movable terminal is connected to the first cantilever. The first piezoelectric drive unit can move the movable terminal in a second axial direction orthogonal to the first axial direction by elastically deforming the first cantilever.
The signal line is connected to the base substrate, faces the movable part in the second axial direction, and is fixed so as to be in contact with the movable terminal when the first cantilever is deformed by the first piezoelectric driving part. It has a terminal.
The grounding line is connected to the base substrate, has a line part disposed at a position farther from the movable part than the fixed terminal, and is parallel to the signal line.

According to another aspect of the present invention, there is provided a method for manufacturing a switch device, comprising: a movable portion having at least one end fixed to a base substrate and having a first region including a movable terminal and a second region including a piezoelectric drive unit; Forming in the plane of the substrate.
A first sacrificial layer covering the first region and having a first height on the base substrate, and a second height higher than the first height and covering the second region. Having a second sacrificial layer.
A signal line laminated on the first sacrificial layer and a ground line laminated on the second sacrificial layer are formed on the base substrate.
The first sacrificial layer and the second sacrificial layer are removed from the base substrate.

It is a top view which shows schematic structure of the switch apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing of the [A1]-[A1] line direction in FIG. It is sectional drawing of the [A2]-[A2] line direction in FIG. It is sectional drawing of the [A3]-[A3] line direction in FIG. It is sectional drawing explaining the effect | action of the switch apparatus shown in FIG. It is sectional drawing which shows schematic structure of the switch apparatus which concerns on a comparative example, (A) shows a switch-off state, (B) shows a switch-on state. It is a top view which shows schematic structure of the switch apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the [B1]-[B1] line direction in FIG. It is sectional drawing of the [B2]-[B2] line direction in FIG. It is sectional drawing of the [B3]-[B3] line direction in FIG. It is sectional drawing of the base substrate explaining the manufacturing method of the switch apparatus shown in FIGS. FIG. 12A is a cross-sectional view of a main part of the base substrate shown in FIG. 11, FIG. 11A is a cross-sectional view in the [B4]-[B4] line direction showing a first region of the base substrate, and FIG. It is sectional drawing of the [B5]-[B5] line direction which shows the area | region of. It is a figure explaining the manufacturing method of the switch apparatus shown in FIGS. 7-10, (A) is sectional drawing of the said 1st area | region, (B) is sectional drawing of the said 2nd area | region. It is a figure explaining the manufacturing method of the switch apparatus shown in FIGS. 7-10, (A) is sectional drawing of the said 1st area | region, (B) is sectional drawing of the said 2nd area | region. It is a figure explaining the manufacturing method of the switch apparatus shown in FIGS. 7-10, (A) is sectional drawing of the said 1st area | region, (B) is sectional drawing of the said 2nd area | region. It is a figure explaining the manufacturing method of the switch apparatus shown in FIGS. 7-10, (A) is sectional drawing of the said 1st area | region, (B) is sectional drawing of the said 2nd area | region. It is a figure explaining the manufacturing method of the switch apparatus shown in FIGS. 7-10, (A) is sectional drawing of the said 1st area | region, (B) is sectional drawing of the said 2nd area | region. It is a top view which shows schematic structure of the switch apparatus which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the [C1]-[C1] line direction in FIG. It is sectional drawing which shows schematic structure of the switch apparatus which concerns on the 4th Embodiment of this invention. It is sectional drawing which shows schematic structure of the switch apparatus which concerns on the 5th Embodiment of this invention.

A switch device according to an embodiment of the present invention includes a base substrate, a movable part, a signal line, and a ground line.
The movable part includes a first cantilever, a movable terminal, and a first piezoelectric drive part. The first cantilever is elastically deformable and has a first end fixed to the base substrate. The movable terminal is connected to the first cantilever. The first piezoelectric drive unit can move the movable terminal in a second axial direction orthogonal to the first axial direction by elastically deforming the first cantilever.
The signal line is connected to the base substrate, faces the movable part in the second axial direction, and is fixed so as to be in contact with the movable terminal when the first cantilever is deformed by the first piezoelectric driving part. It has a terminal.
The grounding line is connected to the base substrate, has a line part disposed at a position farther from the movable part than the fixed terminal, and is parallel to the signal line.

  In the switch device, the line portion is arranged at a position farther from the movable portion than the fixed terminal of the signal line. For this reason, when the first cantilever is deformed by the first piezoelectric drive unit, the movable terminal can be stably brought into contact with the fixed terminal without bringing the movable unit into contact with the ground line.

  Further, by providing a difference in the height of each of the ground line and the signal line from the movable part, it is possible to allow displacement of the fixed terminal at a distance corresponding to the difference in height. Therefore, even when the first piezoelectric drive unit is driven with a relatively high drive voltage, the displacement of the fixed terminal pressed against the movable terminal is absorbed by the difference in height, so the movable unit and the ground line Contact is prevented. Thereby, while realizing stable contact of the movable terminal with respect to the fixed terminal, it is possible to avoid problems such as deformation of the ground line and short circuit due to contact with the movable part.

  The ground line may be disposed only on one side of the signal line (GS or SG structure), or may be disposed on both sides of the signal line (GSG structure). Moreover, the grounded coplanar structure which has a ground surface in the surface on the opposite side of a base substrate may be sufficient.

  The ground line and the signal line are typically formed to cross over the movable part. In the switch device, the signal line is typically formed in parallel on the same plane as the ground line, but is formed at a position lower than both ground lines at a position directly above the movable terminal. Thereby, a difference in height along the second axial direction is provided between the movable portion, the signal line, and the ground line.

The first piezoelectric drive unit may be provided at any position of the movable unit as long as the first cantilever can be elastically deformed in the second axial direction. Typically, the first piezoelectric drive is formed on the surface of the first cantilever. The first piezoelectric drive unit may be formed on the surface of the first cantilever facing the ground line. Even in such a configuration, the movable terminal can be stably brought into contact with the fixed terminal without bringing the first piezoelectric driving unit into contact with the ground line.
In one embodiment, the base substrate has a first surface. The movable portion is formed in the same plane as the first surface, and has a second surface on which the first piezoelectric drive portion and the movable terminal are formed.
As a result, it is possible to manufacture a minute switch device with high accuracy using semiconductor process technology.

In this case, the signal line and the ground line are formed on the first surface in parallel to each other. The line portion is formed in a first arch shape having a first height from the first piezoelectric driving portion, and the fixed terminal has a height from the movable terminal that is the first height. A second arch shape having a second height lower than the height is formed.
Thereby, the contact between the ground line and the movable part can be avoided without impairing the transmission characteristics of the high-frequency signal due to the adoption of the coplanar line structure.

The fixed terminal has a pair of terminal portions that are arranged to face each other in a third axial direction that intersects the first axial direction and the second axial direction, and can contact the movable terminal. Also good.
As a result, a switch device having a pass / open switching mode can be configured.

In this case, the fixed terminal may have a pair of bent portions that bend the pair of terminal portions toward the movable terminal.
Thereby, the intensity | strength with respect to a deformation | transformation of a fixed terminal increases, and the displacement of a signal track | line by the press from a movable terminal can be suppressed.

The movable part may further include a second cantilever, a support, and a second piezoelectric drive part.
The second cantilever is elastically deformable, has a second end fixed to the base substrate, and extends along the first axial direction.
The support supports a first elastically deformable connecting portion connected to the first cantilever, an elastically deformable second connecting portion connected to the second cantilever, and the movable terminal. And a supporting portion.
The second piezoelectric drive unit can move the support in the second axial direction in synchronization with the first piezoelectric drive unit.

  Thereby, since the movable terminal can be moved linearly along the second axial direction, the movable terminal can be brought into more stable contact with the signal line.

The support may further include an intermediate layer disposed between the support and the movable terminal.
According to the above configuration, it is possible to arbitrarily adjust the height of the fixed terminal from the movable terminal depending on the thickness of the intermediate layer.

In a method for manufacturing a switch device according to an embodiment of the present invention, the movable unit including at least one end fixed to the base substrate and having a first region including a movable terminal and a second region including a piezoelectric drive unit is Forming in the plane of the base substrate.
A first sacrificial layer covering the first region and having a first height on the base substrate, and a second height higher than the first height and covering the second region. Having a second sacrificial layer.
A signal line laminated on the first sacrificial layer and a ground line laminated on the second sacrificial layer are formed on the base substrate.
The first sacrificial layer and the second sacrificial layer are removed from the base substrate.

  According to the manufacturing method described above, the heights of the first sacrificial layer and the second sacrificial layer formed on the movable part are made different from each other, so that the height of each of the signal line and the ground line from the movable part is increased. A predetermined difference is provided. As a result, it is possible to manufacture a switch device capable of avoiding problems such as deformation of the ground line and short circuit due to contact with the movable part while realizing stable contact of the movable terminal with the signal line.

The step of forming the first sacrificial layer and the second sacrificial layer may include a step of forming a first resist pattern and a step of forming a second resist pattern on the base substrate. . The first resist pattern opens the first region and covers the second region. The second resist pattern covers the first region and the second region from above the first resist pattern.
Thereby, a desired height difference can be easily provided between the first sacrificial layer and the second sacrificial layer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, an example of an RF-MEMS switch that is mounted on a wireless communication device such as a mobile phone and switches a high-frequency signal between a passing state and an open state will be described as an example.

  In the following embodiments, specific numerical values are given for the configuration of each unit, but the numerical values are merely examples, and the present invention is not limited to these. In order to facilitate understanding and explanation, the ratios of the sizes and thicknesses of the respective parts shown in the drawings are drawn at ratios different from actual ones.

<First Embodiment>
[Configuration of switch device]
1 to 5 show a schematic configuration of a switch device according to the first embodiment of the present invention. 1 is a plan view of the switch device, FIG. 2 is a cross-sectional view taken along the line [A1]-[A1] in FIG. 1, FIG. 3 is a cross-sectional view taken along the line [A2]-[A2] in FIG. FIG. 2 is a cross-sectional view taken along line [A3]-[A3] in FIG. FIG. 5 is a cross-sectional view illustrating an operation example of the switch device. In each figure, the X-axis and Y-axis directions indicate horizontal directions orthogonal to each other, and the Z-axis direction indicates a height direction orthogonal to the X-axis and Y-axis.

  The switch device 1 according to the present embodiment includes a base substrate 10, a movable portion 11, a signal line 12, and a pair of ground lines 131 and 132. The signal line 12 and the pair of ground lines 131 and 132 parallel to the signal line 12 constitute a coplanar line CPW.

  The movable part 11 includes a first cantilever 111, a second cantilever 112, a movable terminal 113, a first piezoelectric drive part 114, and a second piezoelectric drive part 115. As will be described later, the switch device 1 has a switching function for switching between a state in which the movable terminal 113 is separated from the signal line 12 (FIG. 2) and a state in which the movable terminal 113 is in contact with the signal line 12 (FIG. 5).

  The base substrate 10 is formed of a single crystal silicon substrate having a front surface 101 and a back surface 102 parallel to the X axis and the Y axis. The surface 101 of the base substrate 10 is covered with an insulating film 103 made of, for example, a thermal oxide film (silicon oxide film). An opening 104 that accommodates the movable portion 11 is further formed on the surface 101 of the base substrate 10.

  The first cantilever 111 and the second cantilever 112 are each made of an elastically deformable material extending in the X-axis direction, and are made of single crystal silicon in this embodiment. The first and second cantilevers 111 and 112 have the same length (X-axis direction), width (Y-axis direction) and thickness (Z-axis direction), respectively, and X on the same plane in the opening 104. They are provided so as to face each other in the axial direction. One end 111a, 112a (first end, second end) of each of the cantilevers 111, 112 is fixed to the periphery of the opening 104, and the other ends 111b, 112b face each other in the X-axis direction. Yes.

  The length, width, and thickness of the first and second cantilevers 111, 112 are not particularly limited, and are, for example, a length of 50 to 750 μm, a width of 20 to 400 μm, and a thickness of 0.5 to 20 μm. The length is 550 μm, the width is 200 μm, and the thickness is 5 μm.

  A support 117 that supports the movable terminal 113 is provided between the first cantilever 111 and the second cantilever 112. The support body 117 is formed on the same plane as the first cantilever 111 and the second cantilever 112, and includes a first connection part 117a, a second connection part 117b, and a support part 117c. The first connecting portion 117a, the second connecting portion 117b, and the support portion 117c are formed with the same thickness in the same plane as the first and second cantilevers 111 and 112.

  The first connecting portion 117a is connected to the other end 111b of the first cantilever 111 and has a hinge structure that can be elastically deformed. The second connecting portion 117b is connected to the other end 112b of the second cantilever 112 and has a hinge structure that can be elastically deformed. The support portion 117c is connected to the first and second cantilevers 111 and 112 via the first and second connection portions 117a and 117b, respectively, and forms a support surface that supports the movable terminal 113 via the insulating film 103. . The first and second connecting portions 117a and 117b are formed in an appropriate shape that can allow deformation of the support portion 117c with respect to the first and second cantilevers 111 and 112, and the form thereof is not particularly limited.

  The movable terminal 113 is made of a conductive material and is typically made of a metal material, but may be a non-metal material such as a conductive oxide. In the present embodiment, the movable terminal 113 is composed of a laminated film of Ti (titanium) and Au (gold). The movable terminal 113 is formed on the support portion 117c via the insulating film 103, and the thickness thereof is not particularly limited, and is 0.2 μm, for example.

  The base substrate 10 may be composed of a single layer silicon substrate. In this embodiment, the base substrate 10 is an SOI (Silicon On Insulator) substrate having a stacked structure of the first silicon substrate 10A and the second silicon substrate 10B. Composed.

  The first silicon substrate 10 </ b> A is formed with the same thickness as the first and second cantilevers 111 and 112. The thickness of the first silicon substrate 10A is not particularly limited, and is 5 μm, for example. The second silicon substrate 10B is a main part of the thickness of the base substrate 10 and is formed with a thickness sufficient to ensure handling properties. The thickness of the second silicon substrate 10B is not particularly limited and is, for example, 500 μm. The first silicon substrate 10A and the second silicon substrate 10B are bonded to each other through the bonding layer 10C. The bonding layer 10C is made of, for example, a silicon oxide film.

The first cantilever 111, the second cantilever 112, and the support body 117 are formed by processing the shape of the first silicon substrate 10A. In this embodiment, as will be described later, dry etching using a resist pattern formed on the surface of the first silicon substrate 10A as a mask or wet etching using a pattern mask formed of SiN, SiO ₂ or the like is performed. As a result, the first cantilever 111, the second cantilever 112, and the support body 117 are formed in the plane of the first silicon substrate 10A. Accordingly, the surfaces of the first cantilever 111, the second cantilever 112, and the support body 117 are formed in the same plane as the surface 101 of the base substrate 10.

  The opening 104 is constituted by a slit 104a (FIG. 1) penetrating the first silicon substrate 10A and a recess 104b (FIG. 2) formed in the second silicon substrate 10B, which are formed by the etching process described above. The The recess 104b is formed by performing dry etching or wet etching on the second silicon substrate 10B. The concave portion 104b is formed to have a size sufficient to expose the movable portion 11 to the back surface 102 side of the base substrate 10. Thereby, the deformation | transformation to the Z-axis direction in the opening part 104 of the movable part 11 is accept | permitted.

  The first piezoelectric driving unit 114 and the second piezoelectric driving unit 115 are formed on the surface 101 of the base substrate 10 with the insulating film 103 interposed therebetween. The first and second piezoelectric driving units 114 and 115 have the same configuration, and as shown in FIG. 2, the lower electrode layer L1, the upper electrode layer L2, and the lower electrode layer L1 and the upper electrode layer L2 And a laminated film of piezoelectric layers L3 formed between the two.

  The constituent materials of the lower electrode layer L1 and the upper electrode layer L2 are not particularly limited, and may be a metal material or a conductive oxide material. In the present embodiment, the lower electrode layer L1 and the upper electrode layer L2 are composed of a laminated film of Ti, Pt (platinum), and LNO (lanthanum nickelate). The thickness is not particularly limited, and is 0.2 μm, for example. In this embodiment, the piezoelectric layer L3 is made of PZT (lead zirconate titanate) having a thickness of about 1.5 μm, but may be made of other piezoelectric materials such as AlN. The thickness of the piezoelectric layer L3 is not particularly limited, and can be set as appropriate according to the material, the target piezoelectric performance, and the like.

  The first and second piezoelectric drive units 114 and 115 are formed in a substantially rectangular shape having a longitudinal direction in the X-axis direction, and are respectively formed on the surfaces of the first cantilever 111 and the second cantilever 112 (the surface of the insulating film 103). It is formed. The first and second piezoelectric drive units 114 and 115 apply a predetermined voltage between the lower electrode layer L1 and the upper electrode layer L2 to contract the piezoelectric layer L3, thereby causing the first and second cantilevers to contract. 111 and 112 are deformed in the Z-axis direction. As described above, the first and second piezoelectric drive units 114 and 115 are in the first state in which the movable terminal 113 is in contact with the signal line 12 (in the switch-on state in this example), and the movable terminal 113 is separated from the signal line 12. The second state (switch-off state in this example) is configured to be switched.

  The first and second piezoelectric driving units 114 and 115 are driven in synchronization with each other. For example, the second piezoelectric drive unit 115 is configured to move the support 117 (movable terminal 113) in the Z-axis direction in synchronization with the first piezoelectric drive unit 114. Typically, a drive voltage is simultaneously input to the first and second piezoelectric drive units 114 and 115 when the switch is on, and to the first and second piezoelectric drive units 114 and 115 when the switch is off. The drive voltage input is simultaneously released.

  The first and second piezoelectric drive units 114 and 115 may be formed on the back surfaces of the first and second cantilevers 111 and 112, respectively. In this case, each cantilever 111, 112 can be deformed by applying a voltage to each electrode layer so that the piezoelectric layer expands.

  The lower electrode layer L1 and the upper electrode layer L2 respectively have terminal layers T1 and T2 connected to a drive circuit (not shown). The drive circuit is typically composed of a DC circuit, but may be composed of a pulse oscillation circuit. One of the lower electrode layer L1 and the upper electrode layer L2 is connected to a reference potential, and the other is connected to a positive voltage source or a negative voltage source. The reference potential may be a ground potential or a predetermined bias potential.

  The movable part 11 of the switch device 1 is configured as described above. Next, the coplanar type line CPW configured immediately above the movable portion 11 will be described.

  The signal line 12 and the ground lines 131 and 132 are formed on the surface 101 of the base substrate 10 via the insulating film 103, respectively. The signal line 12 is electrically connected to a signal terminal (not shown) formed on the base substrate 10, and the ground lines 131 and 132 are electrically connected to a ground terminal (not shown) formed on the base substrate 10. The signal line 12 is configured as a line that transmits a high-frequency signal in a predetermined wireless communication band. The signal line 12 and the ground lines 131 and 132 are each formed in parallel along the Y-axis direction. The ground lines 131 and 132 are respectively arranged at symmetrical positions with respect to the signal line 12 so as to sandwich the signal line 12. Thereby, a coplanar line type line CPW having a GSG (Ground-Signal-Ground) wiring structure is formed.

  The signal line 12 is formed with a constant line width, and the size thereof is not particularly limited, and is, for example, 20 to 500 μm, and in this embodiment, 180 μm. The signal line 12 includes a fixed terminal 120 that straddles the opening 104 of the base substrate 10 in the Y-axis direction. The fixed terminal 120 is formed in an arch shape directly above the movable portion 11 (movable terminal 113), and faces the movable terminal 113 in the Z-axis direction. A pair of terminal portions 121 and 122 that face each other in the Y-axis direction are formed at the center position of the fixed terminal 120.

  The gap between the pair of terminal portions 121 and 122 is smaller than the width dimension of the movable terminal 113 along the Y-axis direction, and the tip portions of the terminal portions 121 and 122 are on the surface 101 (insulating film 103) of the base substrate 10. It is formed at the same height position from the surface). That is, the movable terminal 113 is configured to come into contact with the pair of terminal portions 121 and 122 when the movable terminal 113 moves toward the fixed terminal 120 of the signal line 12 by driving the movable portion 11.

  The width dimension of the movable terminal 113 and the size of the gap between the terminal portions 121 and 122 are not particularly limited. For example, the width dimension can be set in a range of 30 to 300 μm, and the gap can be set in a range of 30 to 200 μm. In the present embodiment, the width dimension of the movable terminal 113 is 150 μm, and the size of the gap between the terminal portions 121 and 122 is 100 μm.

  The ground lines 131 and 132 each have a ground line part 130 that straddles the opening 104 of the base substrate 10 in the Y-axis direction. These ground line portions 130 are each formed in an arch shape immediately above the movable portion 11 (first and second piezoelectric drive portions 114 and 115). Each ground line portion 130 has the same shape, and the top portion is formed with a flat surface so that the region facing the movable portion 11 is a flat surface.

  The ground lines 131 and 132 are formed with a constant line width, and the size thereof is not particularly limited, and is, for example, 100 to 1500 μm, and is 400 μm in the present embodiment. The distance between the signal line 12 and the ground lines 131 and 132 facing each other in the X-axis direction is not particularly limited, and is, for example, 5 to 250 μm, and in this embodiment, 80 μm.

  For example, the signal line 12 and the ground lines 131 and 132 are formed of a metal material that has little change in the metal surface due to oxidation or the like and does not impair connectivity in connection using wire bonding or flip chip bonding. It is composed of Au (gold). The thickness of the signal line 12 and the ground lines 131 and 132 is not particularly limited, and is about 6 μm in the present embodiment.

  In the present embodiment, the signal line 12 and the pair of ground lines 131 and 132 are formed on the same plane on the surface 101 (the surface of the insulating film 103) of the base substrate 10, but the fixed terminal 120 and the ground line part 130 are These are formed at different height positions with respect to the surface of the movable portion 11 (the surface 101 of the base substrate 11 (the surface of the insulating film 103)). That is, the fixed terminal 120 is opposed to the movable terminal 113 with a first distance (first height H1) in the Z-axis direction, and the ground line portion 130 is more than the first distance in the Z-axis direction. The first and second cantilevers 111 and 112 are opposed to each other with a large second distance (second height H2).

  In the switch device 1 according to the present embodiment, first and second piezoelectric driving units 114 and 115 are formed on the surface of the movable unit 11 facing the ground line unit 130. For this reason, in this embodiment, the height H2 from the surface of the upper electrode layer L2 of each of the first and second piezoelectric driving units 114 and 115 to the bottom surface of the ground line unit 130 is set as the second height.

  The magnitude | size of 1st height H1 and 2nd height H2 is not specifically limited, The relationship of "H1 <H2" should just be satisfy | filled. The height H1 is determined by considering the driving voltage of the first and second piezoelectric driving units 114 and 115, the pressing force of the movable terminal 113 against the fixed terminal 120, and the like in the switch-on state. The size is appropriately set to ensure a stable contact state with 113.

  On the other hand, the difference ΔH (ΔH = H2−H1) between the heights H1 and H2 is the maximum displacement amount in the Z-axis direction (upward in FIG. 2) of the fixed terminal 120 pressed by the movable terminal 113 in the switch-on state. Can be determined accordingly. That is, ΔH is set to such a size that the first and second piezoelectric driving units 114 and 115 do not contact the ground line unit 130 in the switch-on state, and is set to a range of 1 to 20 μm, for example.

  The amount of displacement of the fixed terminal 120 in the Z-axis direction depends on the gap between the movable terminal 113 and the fixed terminal 120, the strength against deformation of the fixed terminal 120, etc. It tends to increase as the pressure increases. Therefore, ΔH can be set according to these various conditions.

  In the present embodiment, the size of the gap (corresponding to the height H1) between the movable terminal 113 and the fixed terminal 120 is set to 8.4 μm. In the present embodiment, when the pressing force from the movable terminal 113 is 400 μN, it is assumed that the fixed terminal 120 is displaced by about 1 μm in the pressing direction, and a value that does not allow the movable portion 11 to contact the ground line portion 130 even in this state ( For example, the height H2 is set to 13 μm.

  Furthermore, the fixed terminal 120 of the present embodiment has a pair of bent portions 121a and 122a that bend the terminal portions 121 and 122 toward the movable terminal 113 (FIG. 3). The bent portions 121a and 122a bend the terminal portions 121 and 122 at an angle such that the surface of the fixed terminal 120 is inclined downward, for example, toward the movable portion 11, but the bent angle is not particularly limited. By forming the bent portions 121a and 122a, the strength against deformation of the fixed terminal 120 is improved, so that displacement of the fixed terminal 120 due to pressing from the movable terminal 113 can be suppressed.

  The switch device 1 according to the present embodiment includes an external connection terminal that is electrically connected to, for example, a mounting board (wiring board) (not shown). The external connection terminals include the signal terminal connected to the signal line 12, the ground terminal connected to the ground lines 131 and 132, the terminal layers T1 and T2 of the first and second piezoelectric driving units 114 and 115, and the like. It may be configured, or may be a plurality of other terminals electrically connected to these. The mounting method is not particularly limited, and may be a wire bonding method or a flip chip method.

  Further, the driving of the switch device 1 of the present embodiment is controlled by a control circuit (not shown). The switch device 1 is electrically connected to the control circuit via a wiring pattern on the mounting board, for example. The control circuit is configured by a computer including a drive circuit, for example, and may be a dedicated control circuit for the switch device 1 or a controller for overall control of the operation of the communication device in which the switch device 1 is mounted. It may be a part of

  Next, a typical operation of the switch device 1 configured as described above will be described.

  In the switch device 1 of this embodiment, in the switch-off state shown in FIG. 2, the fixed terminal 120 of the signal line 12 faces the movable terminal 113 at a distance H1. Thereby, the open state of the signal line 12 is maintained, and signal transmission is interrupted.

  On the other hand, when a predetermined drive voltage is applied to the first and second piezoelectric drive units 114 and 115, the movable unit 11 is caused to elastically deform the first and second cantilevers 111 and 112 in the Z-axis direction. Force is generated. Due to the deformation of the first and second cantilevers 111 and 112, the movable terminal 113 comes into contact with the fixed terminal 120, and the switch device 1 transitions from the switch-off state shown in FIG. 2 to the switch-on state shown in FIG. As a result, the signal line 12 enters a passing state, and a signal is transmitted through the signal line 12.

  In the switch device 1 of the present embodiment, the signal line 12 and the ground lines 131 and 132 constitute the coplanar type line CPW having the above-described configuration, so that a signal caused by impedance mismatch occurring at a high frequency in the switch-on state. Can be prevented, and high-performance high-frequency transmission characteristics can be obtained.

  Here, the ground line portion 130 facing the movable portion 11 is disposed at a position farther from the fixed terminal 120. Therefore, when the first and second cantilever 111 and 112 are deformed by the first and second piezoelectric drive units 114 and 115, the first and second piezoelectric drive units 114 and 115 are replaced with the ground line unit 130. The movable terminal 113 can be brought into contact with the fixed terminal 120 without making contact.

  The switch device 1 of this embodiment will be described in comparison with the switch device 1R shown in FIGS. 6 (A) and 6 (B). 6A shows the switch-off state of the switch device 1R, and FIG. 6B shows the switch-on state of the switch device 1R. The switch device 1R shown in FIG. 6 includes a fixed terminal S and a pair of ground line portions G1 and G2 that are formed at the same height position immediately above the movable terminal E. In the switch device 1R having such a configuration, when the movable terminal E contacts the fixed terminal S in the switch-on state, the fixed terminal S is pressed by the movable terminal E and displaced upward, as shown in FIG. There is a possibility that the piezoelectric driving parts P1, P2 formed on the surfaces of the cantilevers CL1, CL2 may come into contact with the ground line parts G1, G2, respectively.

  On the other hand, in the switch device 1 of the present embodiment, a difference is provided in the height of each of the ground line portion 130 and the fixed terminal 120 from the movable portion 11, and thus the difference between these heights ΔH (H2− The displacement of the fixed terminal 120 at a distance corresponding to H1) can be allowed. Therefore, even when the first and second piezoelectric driving units 114 and 115 are driven with a relatively high driving voltage, the displacement amount of the fixed terminal 120 pressed against the movable terminal 113 is absorbed by the ΔH. Thus, the contact between the movable portion 11 and the ground line portion 130 is prevented. On the other hand, even if the first and second cantilevers 111 and 112 are displaced further upward than the movable terminal 113 by the movable terminal 113 being pressed onto the fixed terminal 120, the above ΔH is appropriately set. Thus, the contact between the movable portion 11 and the ground line portion 130 is similarly prevented.

  As described above, according to the present embodiment, the stable contact of the movable terminal 113 with respect to the fixed terminal 120 is realized, the deformation of the grounding line portion 130 due to the contact with the movable portion 11, the short circuit of the piezoelectric drive portions 114 and 115, and the like. Can be avoided.

  In addition, since the contact between the movable portion 11 and the ground line portion 130 can be avoided regardless of how the wiring distance between the signal line 12 and the ground lines 131 and 132 is changed, the signal line 12 and the ground line 131 can be avoided. , 132 can be reduced. This makes it possible to construct a GSG wiring structure that can be expected to further improve high-frequency characteristics.

  Note that the difference in height between the fixed terminal 120 and the ground line portion 130 at a position immediately above the movable portion 11 is sufficiently small compared to the wiring interval between the signal line 12 and the ground lines 131 and 132, and thus, as described above. It hardly affects the signal transmission characteristics of a coplanar line structure.

  Further, according to the present embodiment, since the terminal portions 121 and 122 of the fixed terminal 120 are bent toward the movable terminal 113 by the bent portions 121a and 122a, the deformation of the fixed terminal 120 due to pressing from the movable terminal 113 is prevented. Strength can be increased. Thereby, since the deformation of the fixed terminal 120 due to the pressing from the movable terminal 113 can be suppressed, a predetermined gap or more can be stably secured between the movable portion 11 and the ground line portion 130.

  Further, according to the present embodiment, since the first and second cantilevers 111 and 112 are used for the drive mechanism of the movable terminal 113, the movable terminal 113 can be moved linearly along the Z-axis direction. Thereby, the movable terminal 113 can be more stably brought into contact with the fixed terminal 120.

<Second Embodiment>
7-10 has shown the structure of the switch apparatus which concerns on the 2nd Embodiment of this invention. 7 is a plan view of the switch device, FIG. 8 is a cross-sectional view taken along the line [B1]-[B1] in FIG. 7, FIG. 9 is a cross-sectional view taken along the line [B2]-[B2] in FIG. FIG. 8 is a cross-sectional view taken along line [B3]-[B3] in FIG. In the present embodiment, the description of the same parts as those of the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

  The switch device 2 of the present embodiment is different from the first embodiment in the configuration of the movable portion 21. As shown in FIGS. 8 and 9, the movable portion 21 of the present embodiment has a support body 17 that supports the movable terminal 113, and the support body 17 is disposed between the support portion 117 c and the movable terminal 113. And an intermediate layer 117d.

  In the movable portion 21 of the present embodiment, since the support body 17 has the intermediate layer 117d, the height between the movable terminal 113 and the fixed terminal 120 can be made smaller than that of the first embodiment. Thereby, when the switch-off state is switched to the switch-on state, the stroke amount until the movable terminal 113 contacts the fixed terminal 120 can be reduced, and the switch switching speed can be increased. Moreover, since the stroke amount of the movable terminal 113 can be reduced, the structure for preventing contact between the movable portion 21 and the ground line portion 130 is further ensured, and a highly reliable switch device can be configured.

  The intermediate layer 117d may be a conductor or an insulator. The intermediate layer 117d may be formed of a constituent material of various functional layers (conductive layer, dielectric layer) formed on the surface 101 of the base substrate 10. Further, the intermediate layer 117d is not limited to a single layer structure, and may have a stacked structure. Further, the thickness of the intermediate layer 117d is not particularly limited, and can be appropriately set according to the size of the gap (corresponding to the height H1) set between the movable terminal 113 and the fixed terminal 120 in the switch-off state. .

  In the present embodiment, the intermediate layer 117d is formed of the same stacked body as the first and second piezoelectric driving units 114 and 115. In this case, the intermediate layer 117d is formed simultaneously with the first and second piezoelectric drive units 114 and 115. As a result, it is not necessary to provide a separate step for forming the intermediate layer 117d, so that productivity is not reduced due to an increase in the number of steps. The intermediate layer 117d is not electrically connected to the first and second piezoelectric drive units 114 and 115, and is formed independently on the support unit 117c. For this reason, deformation of the intermediate layer 117d does not occur when the first and second piezoelectric driving units 114 and 115 are driven, and a stable contact state between the movable terminal 113 and the fixed terminal 120 can be ensured.

[Manufacturing method of switch device]
Next, a manufacturing method of the switch device 2 of the present embodiment configured as described above will be described with reference to FIGS. In the following description, a method for forming the signal line 12 and the ground lines 131 and 132 on the base substrate 10 will be mainly described.

  11 is a plan view showing the base substrate 10 on which the piezoelectric driving units 114 and 115 and the movable terminal 113 are formed. FIG. 12A is an enlarged cross-sectional view in the [B4]-[B4] line direction in FIG. 12B is a cross-sectional view taken along the line [B5]-[B5] in FIG. FIGS. 13A and 13B to FIGS. 17A and 17B correspond to FIGS. 12A and 12B for explaining the formation process of the fixed terminal 120 and one ground line portion 130. FIG. It is an expanded sectional view of each part to do. Since the other one ground line portion is formed at the same time in the same process as the one ground line portion 130, the illustration thereof is omitted.

  First, as the base substrate 10, an SOI substrate is prepared in which a first silicon substrate 10A and a second silicon substrate 10B are bonded through a bonding layer 10C. The bonding layer 10C is made of, for example, a silicon oxide film having a thickness of about 1 μm. The base substrate 10 is initially composed of a wafer substrate of a predetermined size, and after a plurality of elements (switch device 1) are collectively formed on the wafer substrate, the base substrate 10 is predetermined by a dicing process or dry etching of a dicing line. The element size is cut out.

  The base substrate 10 is heat-treated in a thermal oxidation furnace or the like, so that a thermal oxide film is formed on the entire surface including the front surface 101 and the back surface 102 with a predetermined thickness (for example, 0.8 μm). In each figure, only the thermal oxide film (insulating film 103) formed on the surface 101 of the base substrate 10 is shown.

  On the surface 101 of the base substrate 10, as shown in FIG. 11, piezoelectric driving portions 114 and 115, an intermediate layer 117 d, and a movable terminal 113 are formed via an insulating film 103. The piezoelectric driving units 114 and 115, the intermediate layer 117d, and the movable terminal 113 are patterned in a predetermined region using a known photolithography technique.

  In the piezoelectric driving units 114 and 115 and the intermediate layer 117d, a lower electrode layer L1, a piezoelectric layer L3, and an upper electrode layer L2 are sequentially stacked. The lower electrode layer L1 and the upper electrode layer L2 are composed of a laminated film of a Ti layer having a thickness of about 10 nm and a Pt layer having a thickness of about 0.2 μm. The Ti layer and the Pt layer are formed by sputtering, for example, but the film forming method is not limited to this. The piezoelectric layer L3 is composed of a PZT film having a thickness of about 1.5 μm, and is formed by, for example, a sol-gel method, a sputtering method, an MOCVD method, or the like. When forming the piezoelectric driving units 114 and 115 and the intermediate layer 117d, the layers are sequentially formed from the lower layer side film, and after the film formation, patterning is performed in order from the upper layer side film.

  The movable terminal 113 is formed on the intermediate layer 117d. The movable terminal 113 is composed of a laminated film of, for example, a Ti layer having a thickness of about 10 nm and an Au layer having a thickness of about 0.2 μm. The Ti layer and the Au layer are formed by sputtering, for example, but the film forming method is not limited to this.

  Subsequently, as shown in FIG. 7, by forming a slit 104a penetrating in the thickness direction in the first silicon substrate 10A, the first and second cantilevers 111, 112, the support body 117 (first and second The outer shape or contour of the connecting portions 117a and 117b and the supporting portion 117c) is formed. The slit 104a is formed by forming a resist pattern in which a portion where the slit 104a is formed is formed on the surface of the insulating film 103 on the base substrate 10 using a known photolithography technique, and then performing dry etching using the resist pattern as a mask. In addition, the first silicon substrate 10A is sequentially etched. At this time, the bonding layer 10C functions as an etching stopper layer of the slit 104a.

  12A is a schematic cross-sectional view of the base substrate 10 in a region including the movable terminal 113 (first region Z1), and FIG. 12B is a region including the first piezoelectric driving unit 114 (second region). It is a schematic sectional drawing of the base substrate 10 in area | region Z2). As shown in FIG. 12A, a signal terminal 12t connected to the signal line 12 in a subsequent process is formed on the surface of the base substrate 10 adjacent to the formation region of the movable terminal 113 with the slit 104a interposed therebetween. . As shown in FIG. 12B, the surface of the base substrate 10 adjacent to the formation region of the first piezoelectric driving unit 114 across the slit 104a is connected to the ground terminal 13t connected to the ground line 131 in a later step. Is formed.

  Next, in order to form the signal line 12 and the ground lines 131 and 132, a first sacrificial layer W1 that covers the first region Z1 on the surface of the base substrate 10 and a second layer that covers the second region Z2. Each sacrificial layer W2 is formed. The steps of forming the first and second sacrificial layers W1, W2 include a step of forming the first and second lower layer resist patterns W11, W21 and a step of forming the first and second upper layer resist patterns W12, W22. Have.

  First, as shown in FIGS. 13A and 13B, a first liquid resist is formed on the surface of the base substrate 10 by a spin coating method, a spray coating method, a laminate method using a sheet resist, or the like. First and second lower layer resist patterns W11 and W21 are formed on the first and second regions Z1 and Z2, respectively, using a photolithography technique.

  The first lower resist pattern W11 is formed at a predetermined height from the bottom of the slit 104a formed on both sides of the movable terminal 113 so as to open the first region Z1. The second lower layer resist pattern W21 is formed at a predetermined height from the bottom of the slit 104a formed on both sides of the piezoelectric drive units 114 and 115 so as to cover the second region Z2. The first and second lower layer resist patterns W11 and W21 are formed at the same height, and in this embodiment, are about 12 μm.

  Next, as shown in FIGS. 14A and 14B, after the second liquid resist is formed on the surface of the base substrate 10 by a spin coat method, a spray coat method, a laminate method using a sheet resist, or the like, First and second upper resist patterns W12 and W22 are formed on the first and second regions Z1 and Z2, respectively, using a known photolithography technique. The second liquid resist may be the same as or different from the first liquid resist.

  The first upper layer resist pattern W12 covers the first region Z1 (movable terminal 113) from above the first lower layer resist pattern W11. The second upper layer resist pattern W22 covers the second region Z2 (piezoelectric drive unit 114) from above the second lower layer resist pattern W21. The first and second upper layer resist patterns W12 and W22 are formed with a predetermined thickness. In this embodiment, W12 is about 1-2 μm on the peripheral edge W11 and about 8-9 μm on the central movable terminal 113. Yes, W22 is about 6 μm.

  Since the first lower resist pattern W11 is formed so as to open the first region Z1, the first upper resist pattern W12 has a recess V having a predetermined depth on the first region Z1. . On the other hand, since the second lower layer resist pattern W21 is formed so as to cover the second region Z2, the second upper layer resist pattern W22 is formed substantially flat on the second region Z2. As a result, a predetermined height difference H3 is generated between the bottom of the recess V of the first upper layer resist pattern W12 and the upper surface of the second upper layer resist pattern W22.

  The height difference H3 corresponds to the difference ΔH between the height H2 from the piezoelectric driving units 114 and 115 to the ground line unit 130 and the height H1 from the movable terminal 113 to the fixed terminal 120 as shown in FIG. The thickness of the first upper layer resist pattern W12 covering the movable terminal 113 corresponds to the height H1, and the thickness of the second lower layer resist pattern W21 covering the piezoelectric driving portions 114 and 115 and the second upper layer resist. The total thickness of the pattern W22 corresponds to the height H2.

  Here, the taper angle θ of the recess V can be adjusted by the height of the first lower layer resist pattern W11. The taper angle θ of the recess V corresponds to the bending angle of the bent portions 121a and 122a that bend the terminal portions 121 and 122 in the subsequent process of forming the fixed terminal 120. Therefore, for example, when the bending angle is increased, the first lower resist pattern W11 is formed relatively high.

  As described above, the first sacrificial layer W1 and the second sacrificial layer W2 are formed in the first region Z1 and the second region Z2, respectively. Next, a method for forming the fixed terminal 120 and the ground line portion 130 will be described.

  As shown in FIGS. 15A and 15B, a seed layer M1 for plating is formed on the surface of the base substrate 10 from above the first and second sacrificial layers W1 and W2. In the present embodiment, the seed layer M1 is composed of a laminated film of a Ti layer having a thickness of about 5 nm and an Au layer having a thickness of about 200 nm, and is formed by sputtering, vapor deposition, plating, or the like.

  Next, as shown in FIGS. 16A and 16B, a plating layer M2 is formed on the seed layer M1. At this time, a resist pattern PR for forming the terminal portions 121 and 122 of the fixed terminal 120 is formed in the first region Z1. In the present embodiment, the plating layer M2 is composed of gold plating with a thickness of about 6 μm. The seed layer M1 and the plating layer M2 are patterned by a wet etching process or a dry etching process, so that the signal line 12 and the ground lines 131 and 132 formed of a laminate of the seed layer M1 and the plating layer M2 are formed.

Subsequently, as shown in FIGS. 17A and 17B, a recess 104b communicating with the slit 104a is formed in the second silicon substrate 10B, so that an opening for accommodating the movable portion 21 in the base substrate 10 is formed. 104 is formed. In the present embodiment, the recess 104b is formed by a dry etching process for the second silicon substrate 10B. Thereafter, the bonding layer 10C is removed. The bonding layer 10C is removed by dry etching using a gas such as CHF ₃ or C ₄ F ₈ or wet etching using BHF or HF.

  After the formation of the recess 104b, the first and second sacrificial layers W1, W2 are removed, respectively. In the removal process of the first and second sacrificial layers W1 and W2, the base substrate 10 is immersed in a resist stripping solution, and the first and second sacrificial layers W1 and W2 are eluted through the opening 104.

  As described above, the switch device 2 of the present embodiment is manufactured. According to the present embodiment, since the movable portion 21 is formed by processing the surface of the base substrate 10, a minute switch device can be accurately manufactured by using a semiconductor process technology.

  In addition, according to the present embodiment, the resist pattern forming process is performed in two steps, so that the fixed terminal 120 and the ground line portion 130 having different heights from the movable portion 21 are easily formed. be able to. Further, the height difference between the fixed terminal 120 and the ground line portion 130 can be easily adjusted to an arbitrary value. As a result, it is possible to manufacture the switch device 2 capable of avoiding problems such as deformation and short circuit of the ground line portion 130 due to contact with the movable portion 11 while realizing stable contact of the movable terminal 113 with the fixed terminal 120.

<Third Embodiment>
18 and 19 show the configuration of the switch device according to the third embodiment of the present invention. 18 is a plan view of the switch device, and FIG. 19 is a cross-sectional view taken along the line [C1]-[C1] in FIG. In the present embodiment, the description of the same parts as those of the first embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

  The switch device 3 of the present embodiment is different from the first embodiment in the configuration of the movable portion 31. As shown in FIGS. 18 and 19, the movable portion 31 of this embodiment has a single cantilever 311, and a piezoelectric drive portion 114 and a movable terminal 113 formed on the surface of the cantilever 311.

  The movable portion 31 is accommodated in the opening 304 of the base substrate 10, and the surface of the cantilever 311 is formed in the same plane as the surface 101 of the base substrate 10. One end 311a of the cantilever 311 is fixed to the periphery of the opening 104, and the other end 311b is configured as a free end. The cantilever 311 is formed of an elastically deformable silicon substrate that extends in the X-axis direction. In this embodiment, the cantilever 311 is formed by processing the first silicon substrate 10A.

  The movable terminal 113 is formed on the surface of the cantilever 311 on the other end 311b side. The movable terminal 113 faces the fixed terminal 120 of the signal line 12 in the Z-axis direction via the first height H1. On the other hand, the piezoelectric drive unit 114 is formed on the surface of the cantilever 311 so as to face the ground line portion 130 of the ground line 131 in the Z-axis direction via the second height H2. The second height H2 is formed larger than the first height H1 as in the first embodiment.

  In the switch device 3 of the present embodiment configured as described above, a driving force that elastically deforms the cantilever 311 in the Z-axis direction on the movable unit 31 by applying a predetermined driving voltage to the piezoelectric driving unit 114. Occurs. Due to the deformation of the cantilever 311, the movable terminal 113 contacts the fixed terminal 120, and the switch device 3 transitions from the switch-off state shown in FIG. 2 to the switch-on state.

  This embodiment also has the same operational effects as those of the first embodiment described above. That is, since the ground line portion 130 facing the movable portion 31 is disposed at a position farther from the fixed terminal 120, when the cantilever 311 is deformed by the piezoelectric drive portion 114, the piezoelectric drive portion 114 is connected to the ground line portion. The movable terminal 113 can be brought into contact with the fixed terminal 120 without being brought into contact with 130.

<Fourth Embodiment>
FIG. 20 is a cross-sectional view showing a configuration of a switch device according to the fourth embodiment of the present invention. In the present embodiment, description of the same parts as those of the third embodiment will be omitted or simplified, and different parts from the first embodiment will be mainly described.

  The switch device 4 of the present embodiment is different from the above-described third embodiment in the configuration of the ground line. That is, the switch device 4 of the present embodiment has a GS structure in which the ground line 131 is disposed only on one side (the movable part 311 side) of the signal line 12, and the signal line 12 and the ground line 131 form a coplanar type line. To do. Even with such a configuration, high-performance high-frequency transmission characteristics similar to those of the third embodiment described above can be obtained.

  Instead of the structure in which the ground line is disposed on the movable part 311 side of the signal line 12 as described above, an SG structure in which the ground line is disposed on the opposite side of the signal line 12 from the movable part 311 side may be employed. . Even with such a configuration, high-performance high-frequency transmission characteristics similar to those described above can be obtained.

<Fifth Embodiment>
FIG. 21 is a cross-sectional view showing a configuration of a switch device according to the fifth embodiment of the present invention. In this embodiment, the description of the same parts as those of the second embodiment will be omitted or simplified, and different parts from the second embodiment will be mainly described.

  The switch device 5 of the present embodiment includes a ground layer 133 facing the signal line 12 and the ground lines 131 and 132 on the back surface 102 side of the base substrate 10. A grounded coplanar structure is configured by connecting the ground layer 133 to a ground terminal on the base substrate 10. Even with such a configuration, high-performance high-frequency transmission characteristics similar to those of the second embodiment described above can be obtained.

  The ground layer 133 is formed of the same material as that constituting the ground lines 131 and 132. Further, the ground layer 133 is not limited to the example in which the bottom of the opening 104 of the base substrate 10 is formed as shown in the figure, and an opening for opening the opening 104 may be separately formed in the ground layer 133.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

  For example, in the above embodiments, the fixed terminal 120 has a split structure of the pair of terminal portions 121 and 122, and the switch device that switches between passing / opening signals by switching on / off has been described. Instead of this, the present invention can also be applied to a switching device that switches between short-circuiting / passing of a signal by switching on / off without using a fixed structure for the fixed terminal as described above.

  In the above embodiment, the first and second sacrificial layers W1 and W2 having different heights for each region are formed on the base substrate 10 in order to form a height difference between the fixed terminal 120 and the ground line portion 130. did. Alternatively, the sacrificial layers having different heights may be formed by changing the exposure amount of the resist layer for each region using a halftone mask or the like.

DESCRIPTION OF SYMBOLS 1, 2, 3, 4, 5 ... Switch apparatus 10 ... Base board 11, 21, 31 ... Movable part 12 ... Signal line 104, 304 ... Opening part 111, 311 ... 1st cantilever 112 ... 2nd cantilever 113 ... Movable terminal 114 ... 1st piezoelectric drive part 115 ... 2nd piezoelectric drive part 117 ... support body 117a ... 1st connection part 117b ... 2nd connection part 117c ... support part 117d ... intermediate | middle layer 120 ... fixed terminal 121, 122 ... terminal portion 121a, 122a ... bent portion 130 ... ground line portion 131, 132 ... ground line 133 ... ground layer W1 ... first sacrificial layer W2 ... second sacrificial layer Z1 ... first region Z2 ... second region

Claims (9)

A base substrate;
An elastically deformable first cantilever having a first end fixed to the base substrate and extending along a first axial direction, a movable terminal connected to the first cantilever, and the first A movable part having a first piezoelectric drive part capable of moving the movable terminal in a second axial direction orthogonal to the first axial direction by elastically deforming the cantilever;
A signal line connected to the base substrate, facing the movable part in the second axial direction, and having a fixed terminal that can come into contact with the movable terminal when the first cantilever is deformed by the first piezoelectric drive part When,
A switch device comprising: a ground line connected to the base substrate and having a line part disposed at a position farther from the movable part than the fixed terminal, and parallel to the signal line. The switch device according to claim 1,
The base substrate has a first surface;
The switch device has a second surface on which the movable portion is formed in the same plane as the first surface, and on which the first piezoelectric driving portion and the movable terminal are formed. The switch device according to claim 2,
The signal line and the ground line are formed in parallel with each other on the first surface,
The fixed terminal is formed in a first arch shape whose height from the movable terminal is a first height,
The line unit is a switch device formed in a second arch shape in which a height from the first piezoelectric driving unit is a second height higher than the first height. The switch device according to any one of claims 1 to 3,
The fixed terminal includes a pair of terminal portions that are arranged to face each other in a third axial direction that intersects each of the first axial direction and the second axial direction, and that can contact the movable terminal. . The switch device according to claim 4,
The fixed terminal includes a pair of bent portions that bend the pair of terminal portions toward the movable terminal. The switch device according to any one of claims 1 to 5,
The movable part is
An elastically deformable second cantilever having a second end fixed to the base substrate and extending along the first axial direction;
An elastically deformable first connecting portion connected to the first cantilever, an elastically deformable second connecting portion connected to the second cantilever, and a support portion that supports the movable terminal. A support having,
A switch device further comprising: a second piezoelectric driving unit capable of moving the support in the second axial direction in synchronization with the first piezoelectric driving unit. The switch device according to claim 6,
The said support body is a switch apparatus which further has an intermediate | middle layer arrange | positioned between the said support part and the said movable terminal. A movable portion having at least one end fixed to the base substrate and having a first region including a movable terminal and a second region including a piezoelectric drive unit is formed in the plane of the base substrate;
On the base substrate, a first sacrificial layer covering the first region and having a first height, and a second height covering the second region and higher than the first height. Forming a second sacrificial layer having
Forming a signal line laminated on the first sacrificial layer and a ground line laminated on the second sacrificial layer on the base substrate;
A method for manufacturing a switch device, wherein the first sacrificial layer and the second sacrificial layer are removed from the base substrate. It is a manufacturing method of the switch device according to claim 8,
Forming the first sacrificial layer and the second sacrificial layer,
On the base substrate, the first region is opened to form a first resist pattern that covers the second region,
A method for manufacturing a switch device, comprising: forming a second resist pattern covering the first region and the second region from above the first resist pattern on the base substrate.

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