JP5301682B2 - MEMS switch - Google Patents

Abstract

Disclosed is an MEMS switch capable of adjusting characteristic impedance to offset characteristic impedance disruption that may arise when in use. An MEMS switch (SD10) comprises a first tunable capacitor (CA11) disposed corresponding to a first signal line (SL11), a second tunable capacitor (CA12) disposed corresponding to a second signal line (SL12), a bias voltage input terminal (Ti11b) for applying bias voltage to a dielectric layer (24) of the first tunable capacitor (CA11) via the first signal line (SL11) and one electrode layer (25) of the first tunable capacitor (CA11), and a bias voltage input terminal (Ti12b) for applying bias voltage to a dielectric layer (27) of the second tunable capacitor (CA12) via the second signal line (SL12) and one electrode layer (28) of the second tunable capacitor (CA12).

Description

  The present invention relates to a MEMS (Micro Electro Mechanical Systems) switch.

  Semiconductor switches using diodes, FETs, and the like cause characteristics deterioration such as transmission loss increase and isolation reduction as the frequency increases. However, MEMS switches are unlikely to cause such characteristics deterioration, so high-frequency circuits, for example, several GHz Attention has been focused on switching devices suitable for use in circuits through which high-frequency signals of up to several hundred GHz are flowing.

  In general, the MEMS switch has a multilayer structure created by using a known thin film forming method. In a general MEMS switch, a contact electrode is brought into contact with a non-conducting first signal line and a second signal line so that both signal lines are made conductive through the contact electrode, and contact of the contact electrode with both signal lines is made. It has a function of bringing both signal lines into a non-conductive state by solving.

  The MEMS switch is designed to have a predetermined characteristic impedance such as 50Ω or 75Ω, for example. However, when used in a high frequency circuit, the characteristic impedance may be disturbed by external influences.

  Although this disturbance of characteristic impedance can be estimated to some extent according to the use of the MEMS switch, the characteristic impedance is adjusted based on the estimation result by adjusting the signal line structure (line width, line length, line thickness, etc.). Even if the impedance is adjusted in advance, an unexpected external influence may actually occur. Therefore, it is difficult to secure an optimum characteristic impedance. Moreover, it cannot be said that it is preferable from the surface of versatility and a cost reduction to manufacture the MEMS switch from which a signal line structure differs for every use.

  In other words, if the characteristic impedance can be adjusted so as to cancel out the disturbance of the characteristic impedance that may occur during use, the optimum characteristic impedance for the MEMS switch can be ensured in any application. As a result, it is possible to avoid deterioration in characteristics such as an increase in transmission loss and a decrease in isolation caused by disturbance of characteristic impedance.

Japanese Patent Application No. 2008-277743

  An object of the present invention is to provide a MEMS switch capable of adjusting a characteristic impedance so as to cancel out a disturbance of the characteristic impedance that may occur during use.

  In order to achieve the above-mentioned object, the present invention brings both signal lines into a conductive state through the contact electrodes by bringing the contact electrodes into contact with the non-conductive first signal line and the second signal line. A MEMS switch for bringing both signal lines into a non-conductive state by releasing contact of the contact electrodes, the MEMS switch including a first tunable capacitor provided corresponding to the first signal line, and a second signal line And a second tunable capacitor provided corresponding to the first tunable capacitor, and a first voltage line for applying a bias voltage to the dielectric layer of the first tunable capacitor through one electrode layer side of the first signal line and the first tunable capacitor. 1 bias voltage input terminal, biased to the dielectric layer of the second tunable capacitor through one electrode layer side of the second signal line and the second tunable capacitor Comprising a first bias voltage input terminal for applying a pressure, a.

  According to this MEMS switch, by applying a bias voltage to the dielectric layer of the first tunable capacitor and the dielectric layer of the second tunable capacitor, the relative dielectric constant of the dielectric layers of both tunable capacitors is changed. The capacitance of both tunable capacitors can be changed by the change, and the characteristic impedance of the MEMS switch can be changed by the change.

  In other words, even if the characteristic impedance (for example, 50Ω or 75Ω) of the MEMS switch mounted on the circuit board is disturbed by an external influence, the capacitances of both tunable capacitors are changed by the bias voltage so as to cancel the disturbance. By doing so, the characteristic impedance can be adjusted to an optimum value.

  According to various embodiments of the present invention, the characteristic impedance can be adjusted so as to cancel out the disturbance of the characteristic impedance that occurs during use, so that the optimum characteristic impedance for the MEMS switch can be ensured, and thus the characteristic impedance can be reduced. It is possible to avoid deterioration in characteristics such as transmission loss increase and isolation decrease due to disturbance.

  The above-described object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

FIG. 1 is a top view of the MEMS switch according to the first embodiment of the present invention. 2 (S1) is a sectional view taken along line S1-S1 in FIG. 1, FIG. 2 (S2) is a sectional view taken along line S2-S2 in FIG. 1, and FIG. 2 (S3) is taken along line S3-S3 in FIG. 2 is a sectional view taken along the line S4-S4 in FIG. 1, and FIG. 2 (S5) is a sectional view taken along the line S5-S5 in FIG. 3 (S6) is a sectional view taken along line S6-S6 in FIG. 1, FIG. 3 (S7) is a sectional view taken along line S7-S7 in FIG. 1, and FIG. 3 (S8) is taken along line S8-S8 in FIG. 3 is a sectional view taken along line S9-S9 in FIG. 1, and FIG. 3 (S10) is a sectional view taken along line S10-S10 in FIG. FIG. 4 is an explanatory diagram of a usage method and functions of the MEMS switch shown in FIG. FIG. 5 is an explanatory diagram of the usage and functions of the MEMS switch shown in FIG. FIG. 6 is a top view of the MEMS switch according to the second embodiment of the present invention. FIG. 7 is an explanatory diagram of a usage method and functions of the MEMS switch shown in FIG. FIG. 8 is a top view of the MEMS switch according to the third embodiment of the present invention. 9 (S11) is a sectional view taken along line S11-S11 in FIG. 8, FIG. 9 (S12) is a sectional view taken along line S12-S12 in FIG. 8, and FIG. 9 (S13) is taken along line S13-S13 in FIG. It is sectional drawing which follows. 10 (S14) is a sectional view taken along line S14-S14 in FIG. 8, FIG. 10 (S15) is a sectional view taken along line S15-S15 in FIG. 8, and FIG. 10 (S16) is taken along line S16-S16 in FIG. FIG. 10 (S17) is a sectional view taken along line S17-S17 in FIG. 8, and FIG. 10 (S18) is a sectional view taken along line S18-S18 in FIG. FIG. 11 is an explanatory diagram of usage and functions of the MEMS switch shown in FIG. FIG. 12 is an explanatory diagram of the usage and functions of the MEMS switch shown in FIG.

[First Embodiment]
1 to 5 show a first embodiment of the present invention (MEMS switch). In this description, for convenience of explanation, the left, right, bottom, top, front, back, and back directions in FIG. 1 and the directions corresponding to these in the other drawings are respectively represented as front, back, left, right, top, and bottom. .

  First, the configuration of the MEMS switch SD10 will be described with reference to FIGS.

  The MEMS switch SD10 shown in FIGS. 1 to 3 has a multilayer structure created by using a known thin film forming method. In one embodiment, the MEMS switch SD10 is configured to have a front-rear dimension of about 1.0 mm, a left-right dimension of about 2.0 mm, and a vertical dimension of about 0.5 mm.

  The MEMS switch SD10 includes a base BS11, a lever FL11, a contact electrode CT11, a first tunable capacitor CA11, a connection terminal Tca11, a second tunable capacitor CA12, a connection terminal Tca12, and a first signal line SL11. A second signal line SL12, ground terminals Tg11 and Tg12, drive voltage input terminals Ti11a and Ti12a, and bias voltage input terminals Ti11b and Ti12b.

The base BS 11 is made of a first base layer 11 made of Si or the like, SiO ₂ or the like, and
A first insulator layer 12 formed on the first base layer 11 made of Si or the like, and, the second base layer 13 formed on the first insulator layer 11 made of SiO ₂ or the like, and And a second insulator layer 14 formed on the second base layer 13.

  The first base layer 11 and the first insulator layer 12 are formed with a first through hole PH11 having a substantially rectangular outline in top view. In addition, the second base layer 13 and the second insulator layer 14 are formed with two second through holes PH12 having a substantially rectangular outline in top view and a smaller front-rear dimension than the first through hole PH11 in parallel. ing. Between the two second through holes PH12, there are a band-shaped base layer 13a and a band-shaped insulator layer 14a which are base materials of the lever FL11. In one embodiment, the lever FL11 may be operable by removing only the first insulator layer 12 without forming the first through hole PH11 in the first base layer 11.

  Further, on the upper left side and the upper right side of the base BS 11, a pair of first electrode layers 15 made of Ti / Pt in which a Ti layer and a Pt layer are stacked and having a substantially rectangular outline in top view are formed. . Further, a pair of second electrode layers 16 made of Ti / Pt and having a substantially rectangular outline in top view are formed on the front upper surface and the rear upper surface of the base BS 11 with the same thickness as the first electrode layer 15. ing.

  The lever FL11 has two drive portions FL11a, a displacement portion FL11b located between the drive portions FL11a, and a hinge portion FL11c that connects each drive portion FL11a and the displacement portion FL11b.

  Each drive part FL11a uses the left and right portions of the band-shaped base layer 13a and the band-shaped insulator layer 14a described above as its base material. On the left and right portions, a third electrode layer 17 made of Ti / Pt and having a substantially rectangular outline in top view is formed continuously with the first electrode layer 15 with the same thickness as the first electrode layer 15. ing. On the third electrode layer 17, a piezoelectric layer 18 made of PZT or the like and having the same top view contour as that of the third electrode layer 17 is formed. Further, a fourth electrode layer 19 made of Ti / Pt and having the same top view contour as that of the piezoelectric layer 18 is formed on the piezoelectric layer 18.

  Displacement part FL11b uses the center part of the strip | belt-shaped base layer 13a and the strip | belt-shaped insulator layer 14a mentioned above as the base material. A dummy electrode layer 20 made of Ti / Pt and having a substantially rectangular outline in top view has the same thickness as the third electrode layer 17 at the center in the front-rear direction of the center portion of the band-shaped base layer 13a and the band-shaped insulator layer 14a. Is formed. On the dummy electrode layer 20, a dummy piezoelectric layer 21 made of PZT or the like and having the same top profile as the dummy electrode layer 20 is formed with the same thickness as the piezoelectric layer 18. Further, on the dummy piezoelectric layer 21, a dummy electrode layer 22 made of Ti / Au in which a Ti layer and an Au layer are stacked and having the same top view outline as the dummy piezoelectric layer 21 is formed on the fourth electrode layer 19. They are formed with the same thickness. Further, on the dummy electrode layer 22, a contact electrode CT 11 made of Ti / Au and having the same top view contour as the dummy electrode layer 22 is formed.

  A lower electrode layer 23 made of Ti / Pt and having a substantially rectangular outline in top view is a dummy electrode layer 20 on the front side of the central portion of the band-shaped base layer 13a and the band-shaped insulator layer 14a constituting the displacement part FL11b. Are formed with the same thickness. On the lower electrode layer 23, a dielectric layer 24 made of PZT or the like and having the same top profile as the lower electrode layer 23 is formed with the same thickness as the dummy piezoelectric layer 21. Further, on the dielectric layer 24, the upper electrode layer 25 made of Ti / Pt and having the same top view contour as the dielectric layer 24 has the same thickness as the dummy electrode layer 22 or 0 than the dummy electrode layer 22. It is formed slightly thin about 0.01 μm to 0.5 μm. Here, the lower electrode layer 23, the dielectric layer 24, and the upper electrode layer 25 constitute a first tunable capacitor CA11, and the first tunable capacitor CA11 is disposed on the displacement portion FL11b. Further, on the upper electrode layer 25 of the first tunable capacitor CA11, a connection terminal Tca11 made of Ti / Au and having the same top view outline as the upper electrode layer 25 is formed. The upper electrode layer connection terminal Tca11 is formed to have the same thickness as the contact electrode CT11 or slightly thinner than the contact electrode CT11 by about 0.01 μm to 0.5 μm. As can be seen from FIG. 2 (S3), the height of the upper surface of the connection terminal Tca11 coincides with the height of the upper surface of the contact electrode CT11 or is slightly lower by about 0.01 μm to 0.5 μm.

  A lower electrode layer 26 made of Ti / Pt and having a substantially rectangular outline in top view is a dummy electrode layer on the rear side of the central portion of the band-shaped base layer 13a and the band-shaped insulator layer 14a constituting the displacement part FL11b. The same thickness as 20 is formed. On the lower electrode layer 26, a dielectric layer 27 made of PZT or the like and having the same top profile as the lower electrode layer 26 is formed with the same thickness as the dummy piezoelectric layer 21. Further, on the dielectric layer 27, the upper electrode layer 28 made of Ti / Pt and having the same top view contour as the dielectric layer 27 has the same thickness as the dummy electrode layer 22, or 0 than the dummy electrode layer 22. It is formed slightly thin about 0.01 μm to 0.5 μm. Here, the lower electrode layer 26, the dielectric layer 27, and the upper electrode layer 28 constitute a second tunable capacitor CA12, and the second tunable capacitor CA12 is disposed on the displacement portion FL11b. Further, on the upper electrode layer 28 of the second tunable capacitor CA12, a connection terminal Tca12 made of Ti / Au and having the same top view contour as that of the upper electrode layer 28 is formed. The connection terminal Tca12 is formed to have the same thickness as the contact electrode CT11 or slightly thin about 0.01 μm to 0.5 μm. As can be seen from FIG. 2 (S3), the height of the upper surface of the connection terminal Tca12 coincides with the height of the upper surface of the contact electrode CT11 or is slightly lower by about 0.01 μm to 0.5 μm.

  Each hinge portion FL11c uses as its base material a portion sandwiched between the front and rear portions and the central portion of the band-shaped base layer 13a and the band-shaped insulator layer 14a described above. By forming through holes (without reference numerals) in these base materials, each hinge portion FL11c is given flexibility to serve as a hinge. As can be seen from FIG. 1 and FIG. 3 (S8), the third electrode layer 17 on each drive portion FL11a is formed so as to reach the displacement portion FL11b via each hinge portion FL11c. The end of the layer 17 reaches both the lower electrode layer 23 of the first tunable capacitor CA11 and the lower electrode layer 26 of the second tunable capacitor CA12.

  The first signal line SL11 and the second signal line SL12 are made of Ti / Au, and have a cross-sectional shape obtained by bending a flat base material by 90 degrees and further bending by 90 degrees in the opposite direction. The lower surface of the front portion of the first signal line SL11 is connected to the upper surface of the second electrode layer 16 on the front side, and the lower surface of the rear portion of the second signal line SL12 is connected to the upper surface of the second electrode layer 16 on the rear side. Yes. Since the first signal line SL11 and the second signal line SL12 are formed to be line-symmetric with respect to the S8-S8 line, the upper and lower surfaces of the rear portion of the first signal line SL11 and the second signal line SL12 are formed. The upper and lower surfaces of the front portion of the are flush with each other.

  In addition, as can be seen from FIG. 1, the left and right dimensions of the first signal line SL11 and the second signal line SL12 are larger than the left and right dimensions of the contact electrode CT11 and the connection terminals Tca11 and Tca12. Further, the rear portion of the first signal line SL11 and the front portion of the second signal line SL12 extend above the contact electrode CT11, and the first signal line SL11 and the front portion are between the rear portion and the front portion. A gap GA is provided for non-conduction with the second signal line SL12.

  Further, the contact electrode CT11, the connection terminal Tca11, and the connection terminal Tca12 have substantially the same top surface height, or the contact electrode CT11 is slightly higher than the connection terminal Tca11 or the connection terminal Tca12 by about 0.01 μm to 0.5 μm. Therefore, the lower surface of the rear portion of the first signal line SL11, the lower surface of the front portion of the second signal line SL12, and the contact electrode CT11, the lower surface of the rear portion of the first signal line SL11, and the connection terminal Between the upper surface of the Tca11 and between the lower surface of the front portion of the second signal line SL12 and the upper surface of the connection terminal Tca12, gaps (not shown) having substantially the same vertical dimension are formed.

  The ground terminal Tg11 is made of Ti / Au, and is formed on the first electrode layer 15 on the left side so that the outline in top view is substantially rectangular. The ground terminal Tg12 is made of Ti / Au and is formed on the first electrode layer 15 on the right side so that the outline in top view is substantially rectangular.

  The drive voltage input terminal Ti11a is made of Ti / Au, and is formed at the left end on the fourth electrode layer 19 of the left drive unit FL11a so that the outline in top view is substantially rectangular. The drive voltage input terminal Ti12a is made of Ti / Au and is formed at the right end on the fourth electrode layer 19 of the right drive unit FL11a so that the outline in top view is substantially rectangular.

  The bias voltage input terminal Ti11b is made of Ti / Au, and is formed on the upper surface on the left side of the base BS11 so that the outline in top view is substantially rectangular and aligned with the drive voltage input terminal Ti11a. The bias voltage input terminal Ti12b is made of Ti / Au, and is formed on the right upper surface of the base BS11 so that the outline in top view is substantially rectangular and aligned with the drive voltage input terminal Ti12a. Yes.

  The bias voltage input terminal Ti11b and the front second electrode layer 16 are connected by a high resistance line HRL11, and the bias voltage input terminal Ti12b and the rear second electrode layer 16 are connected by a high resistance line HRL12. ing. These high resistance lines HRL11 and HRL12 are made of a high resistance material such as TaN, and have a higher resistivity than the first signal line SL11 and the second signal line SL12.

  Next, with reference to FIG.4 and FIG.5, the usage method and function of MEMS switch SD10 which concern on one Embodiment of this invention are demonstrated.

  In use, the MEMS switch SD10 is mounted on a circuit board or the like as shown in FIG. The positive side of the first variable DC power source DC11a is connected to the drive voltage input terminal Ti11a, the positive side of the second variable DC power source DC11b is connected to the bias voltage input terminal Ti11b, and the negative side of both the variable DC power sources DC11a and DC11b. Is connected to the ground terminal Tg11. The positive side of the third variable DC power source DC12a is connected to the drive voltage input terminal Ti12a, the positive side of the fourth variable DC power source DC11b is connected to the bias voltage input terminal Ti12b, and the negative side of both the variable DC power sources DC12a and DC12b. Is connected to the ground terminal Tg11.

  As will be described later, since the drive voltages applied to the drive voltage input terminals Ti11a and Ti12a have the same value, in one embodiment, one variable DC power supply can be shared for applying the drive voltage. In addition, since the bias voltages applied to the bias voltage input terminals Ti11b and Ti12b have the same value, in one embodiment, one variable DC power supply different from the drive voltage application power supply is shared for bias voltage application. May be. In one embodiment, the variable DC power supply may be replaced with a DC voltage input line provided on a circuit board or the like as long as voltage application described later can be performed in the same manner.

  A high frequency signal line (input side) provided on a circuit board or the like is connected to the first signal line SL11, and a high frequency signal line (output side) is connected to the second signal line SL12. Conversely, the high frequency signal line (input side) may be connected to the second signal line SL12, and the high frequency signal line (output side) may be connected to the first signal line SL11.

  At the time of use, a DC voltage of a predetermined value (hereinafter referred to as drive voltage) is applied from the first variable DC power supply DC11a to the drive voltage input terminal Ti11a, and this is applied to the drive voltage input terminal Ti12a from the third variable DC power supply DC12a. The same driving voltage is applied. Also, a DC voltage of a predetermined value (hereinafter referred to as a bias voltage) is applied from the second variable DC power supply DC11b to the bias voltage input terminal Ti11b, and the same as this from the fourth variable DC power supply DC12b to the bias voltage input terminal Ti12b. A value bias voltage is applied.

  The drive voltage applied to the drive voltage input terminal Ti11a is applied to the piezoelectric layer 18 of the drive unit FL11a through the fourth electrode layer 19 constituting the drive unit FL11a on the left side of the lever FL11. Further, the drive voltage applied to the drive voltage input terminal Ti12a is applied to the piezoelectric layer 18 of the drive unit FL11a through the fourth electrode layer 19 constituting the drive unit FL11a on the right side of the lever FL11.

  As a result, as shown in FIG. 5, the piezoelectric layer 18 formed by the two driving portions FL11a contracts due to the piezoelectric effect. Due to the contraction of the piezoelectric layer 18, the hinge portion FL11c side of both the driving portions FL11a is warped upward, so that the displacement portion FL11b of the lever FL11 is displaced upward due to the warping, and the upper surface of the contact electrode CT11 is changed by the upward displacement. The lower surface of the rear portion of the first signal line SL11 and the lower surface of the front portion of the second signal line SL12 are contacted. By this contact, both signal lines SL11 and SL12 are brought into conduction through the contact electrode CT11. That is, the high-frequency signal input to the first signal line SL11 is output from the second signal line SL12 via the first signal line SL11, the contact electrode CT11, and the second signal line SL12.

  Further, the first tunable capacitor CA11 and the second tunable capacitor CA12 are disposed on the displacement portion FL11b of the lever FL11, and the lower surface of the rear portion of the first signal line SL11 and the front portion of the second signal line SL12 are disposed. The gap between the lower surface and the contact electrode CT11, the gap between the lower surface of the rear portion of the first signal line SL11 and the upper surface of the connection terminal Tca11, the lower surface of the front portion of the second signal line SL12, and the upper surface of the connection terminal Tca12 Since the gap is substantially the same, the first tunable capacitor is almost simultaneously when the upper surface of the contact electrode CT11 contacts the lower surface of the rear portion of the first signal line SL11 and the lower surface of the front portion of the second signal line SL12. The upper surface of the connection terminal Tca11 of CA11 is in contact with the lower surface of the rear portion of the first signal line SL11 and is electrically connected; and The upper surface of the connection terminal Tca12 second tunable capacitor CA12 are electrically connected in contact with the lower surface of the front portion of the second signal line SL12.

  On the other hand, the bias voltage applied to the bias voltage input terminal Ti11b passes through the high resistance line HRL11, the front second electrode layer 16, the first signal line SL11, the connection terminal Tca11, and the upper electrode layer 25 of the first tunable capacitor CA11. Applied to the dielectric layer 24 of the first tunable capacitor CA11. The bias voltage applied to the bias voltage input terminal Ti12b is the high resistance line HRL12, the second electrode layer 16 on the rear side, the second signal line SL12, the connection terminal Tca12, and the upper electrode layer 28 of the second tunable capacitor CA12. Through the dielectric layer 27 of the second tunable capacitor CA12.

  As a result, the relative dielectric constants of the dielectric layers 24 and 27 of both tunable capacitors CA11 and CA12 change, and the capacitances of both tunable capacitors CA11 and CA11 change due to the change, and the change causes the characteristic impedance of the MEMS switch SD10. Changes.

  That is, even if the characteristic impedance (for example, 50Ω or 75Ω) of the MEMS switch SD10 mounted on the circuit board or the like is disturbed by an external influence, the capacitances of both the tunable capacitors CA11 and CA11 are set so as to cancel the disturbance. If the bias voltage is changed, the characteristic impedance can be adjusted to an optimum value.

  Next, effects obtained by the MEMS switch SD10 according to the embodiment of the present invention will be described.

  (1) In the MEMS switch SD10 according to one embodiment of the present invention, the capacitance of both the tunable capacitors CA11 and CA11 is changed by the bias voltage so as to cancel the disturbance of the characteristic impedance that occurs during use. Since the characteristic impedance can be adjusted, the optimum characteristic impedance for the MEMS switch SD10 can be ensured. As a result, it is possible to avoid deterioration in characteristics such as an increase in transmission loss and a decrease in isolation caused by disturbance of characteristic impedance.

  (2) In the MEMS switch SD10 according to the embodiment of the present invention, the first tunable capacitor CA11 is provided corresponding to the first signal line SL11, and the second corresponding to the second signal line SL12. Since the two tunable capacitors CA12 are provided, the intended characteristic impedance adjustment is effectively performed on the entire line (the first signal line SL11, the contact electrode CT11, and the second signal line SL12) through which the high-frequency signal flows. Can do.

  (3) In the MEMS switch SD10 according to the embodiment of the present invention, the first tunable capacitor CA11 and the second tunable capacitor CA12 are disposed on the displacement portion FL11b of the lever FL11, and the first signal line A gap between the lower surface of the rear portion of SL11 and the lower surface of the front portion of the second signal line SL12 and the contact electrode CT11; a gap between the lower surface of the rear portion of the first signal line SL11 and the upper surface of the connection terminal Tca11; Since the gap between the lower surface of the front portion of the two-signal line SL12 and the upper surface of the connection terminal Tca12 is substantially the same, the upper surface of the contact electrode CT11 is moved upward by the displacement portion FL11b of the lever FL11. The first tunable substantially simultaneously with the lower surface of the rear portion of the second signal line SL12 and the lower surface of the front portion of the second signal line SL12. The upper surface of the connection terminal Tca11 of the capacitor CA11 is brought into contact with and electrically connected to the lower surface of the rear portion of the first signal line SL11, and the upper surface of the connection terminal Tca12 of the second tunable capacitor CA12 is connected to the second signal line SL12. It can be made to contact and electrically connect to the lower surface of the front part.

  In this way, the first tunable capacitor CA11 is connected to the first signal line SL11 only when the first signal line SL11 and the second signal line SL12 become conductive through the contact electrode CT11, and the first The desired characteristic impedance can be adjusted by connecting the second tunable capacitor CA12 to the two-signal line SL12.

  In one embodiment, the upper surface height of the contact electrode CT11 is slightly higher than the upper surface height of the connection terminal Tca11 and the upper surface height of the connection terminal Tca12 by about 0.01 μm to 0.5 μm, thereby making the first signal line SL11. The contact pressure between the lower surface of the rear portion and the lower surface of the front portion of the second signal line SL12 and the contact electrode CT11 is the contact pressure between the lower surface of the rear portion of the first signal line SL11 and the upper surface of the connection terminal Tca11. Since the contact pressure between the lower surface of the front portion of the two-signal line SL12 and the upper surface of the connection terminal Tca12 can be increased, the stability of the conduction state of the switch is improved.

  (4) In the MEMS switch SD10 according to one embodiment of the present invention, the bias voltage applied to the bias voltage input terminal Ti11b is applied to the dielectric layer 24 of the first tunable capacitor CA11 via the high resistance line HRL11. In addition, since the bias voltage applied to the bias voltage input terminal Ti12b is applied to the dielectric layer 27 of the second tunable capacitor CA12 via the high resistance line HRL12, a high resistance is applied from the first signal line SL11. A high frequency signal leaks to the line HRL11 side, and a high frequency signal leaks from the second signal line SL12 to the high resistance line HRL12 side. Thereby, characteristic deterioration of the high frequency signal which flows via 1st signal track | line SL11, contact electrode CT11, and 2nd signal track | line SL12 can be prevented.

  (5) In the MEMS switch SD10 according to the embodiment of the present invention, the contact electrode CT11 is in contact with the first signal line SL11 and the second signal line SL12, and the connection terminal Tca11 of the first tunable capacitor CA11. Are in contact with or in proximity to the first signal line SL11 and the connection terminal Tca12 of the second tunable capacitor CA12 is in contact with or in proximity to the second signal line SL12, the tunables from the connection terminals Tca11 and Tca12. By applying a bias voltage to the capacitors CA11 and CA12, an electrostatic attractive force is generated between the first signal line SL11 and the lower electrode layer 23 of the first tunable capacitor CA11, and the second signal line SL12 and the second signal line SL12 An electrostatic attractive force is generated between the lower electrode layer 26 of the tunable capacitor CA12. For this reason, since the contact electrode CT11 and both signal lines SL11 and SL12 can be strongly brought into contact by the electrostatic attraction in addition to the piezoelectric power of the lever FL11 (upward displacement force of the displacement portion FL11b), the conduction state of the switch Improves stability. In addition, the MEMS switch SD10 according to the embodiment of the present invention is used in a mode in which the piezoelectric FL of the lever FL11 is not used in the conductive state of the switch by utilizing the latching state in which the contact continues even with the electrostatic attraction alone. You can also.

  (6) The MEMS switch SD10 according to an embodiment of the present invention can be regarded as a device having a filter function. The ability to vary the characteristic impedance means that the filter function can be varied. Since the two tunable capacitors CA11 and CA12 provided on both sides of the contact electrode CT11 are connected to the ground, the first signal line SL11 and the second signal line through which high-frequency signals pass through the tunable capacitors CA11 and CA12. A low-pass filter can be configured by combining with the inductance component of SL12. If the capacitances of the tunable capacitors CA11 and CA12 are changed, the cut-off frequency can be adjusted.

  As the MEMS switch SD10 according to an embodiment of the present invention, the piezoelectric layer 18, the dummy piezoelectric layer 21, the dielectric layer 24 that configures the first tunable capacitor CA11, and the second tuner that configure each drive unit FL11a. The dielectric layers 27 constituting the bull capacitor CA12 are respectively formed by PZT, but instead of PZT, lead zirconate, lead titanate, lead magnesium niobate, lead nickel niobate, barium titanate, Sodium bismuth titanate, potassium sodium niobate, strontium bismuth tantalate, and the like can be used.

In the MEMS switch SD10 according to the embodiment of the present invention, the first electrode layer 15, the second electrode layer 16, the third electrode layer 17, the fourth electrode layer 19, and the dummy electrode layers 20 and 22 constituting each driving unit FL11a. , Contact electrode CT11, lower electrode layer 23 and upper electrode layer 25 constituting the first tunable capacitor CA11, connection terminal Tca11, lower electrode layer 26 and upper electrode layer 28 constituting the second tunable capacitor CA12, connection terminal Tca12 The first signal line SL11, the second signal line SL12, the ground terminals Tg11 and Tg12, the drive voltage input terminals Ti11a and Ti12a, and the bias voltage input terminals Ti11b and Ti12b are respectively Ti layers in which a Ti layer and a Pt layer are stacked. / Pt or Ti / Au with Ti layer and Au layer laminated In another embodiment of the present invention, any one of a Cr layer, a Zr layer, a TiN layer, or a TiO ₂ layer can be used instead of the Ti layer of Ti / Pt and / or Ti / Au. Further, any one of an Au alloy layer, a Cu layer, and an Ag layer can be used instead of the Ti / Pt Pt layer. Furthermore, any one of an Au alloy layer, a Cu layer, and an Ag layer can be used instead of the Ti / Au Au layer. In another embodiment of the present invention, a single layer composed of a Pt layer, an Au layer, an Au alloy layer, a Cu layer, or an Ag layer may be used instead of Ti / Pt or Ti / Au. In one embodiment of the present invention, the thickness of the Ti layer, Cr layer, Zr layer, TiN layer, or TiO ₂ layer can be 1 nm to 100 nm, and the Pt layer, Au layer, Au alloy layer, Cu The film thickness of the layer or the Ag layer can be 0.1 μm to 30 μm. As will be apparent to those skilled in the art, the materials that make up each element included in the MEMS switch SD30 according to various embodiments of the present invention are not limited to those explicitly set forth herein, and are within the scope of the present invention. As long as it does not deviate from the above, it can be changed as appropriate.

  In the MEMS switch SD10 according to the embodiment of the present invention, as described above, the dummy electrode layer 20 is disposed on the displacement portion FL11b in order to align the upper surface height of the contact electrode CT11 with the upper surface height of the connection terminals Tca11 and Tca12. A dummy piezoelectric layer 21 and a dummy electrode layer 22 are formed, and a contact electrode CT11 is formed thereon. In another embodiment, instead of the dummy piezoelectric layer 21 and the dummy electrode layer 22, a thickness obtained by adding the thicknesses of the dummy piezoelectric layer 21 and the dummy electrode layer 22, or the dummy piezoelectric layer 21 and A contact electrode CT11 having a thickness obtained by adding about 0.01 μm to 0.5 μm to the thickness obtained by adding the thickness of the dummy electrode layer 22 may be formed on the dummy electrode layer 20. In one embodiment, instead of the dummy electrode layer 20, the dummy piezoelectric layer 21, and the dummy electrode layer 22, the thickness obtained by adding the thicknesses of the dummy electrode layer 20, the dummy piezoelectric layer 21, and the dummy electrode layer 22 is added. Can be formed on the strip-shaped insulator layer 14a.

  In the MEMS switch SD10 according to the embodiment of the present invention, as described above, one ground terminal Tg11 is shared as the ground terminal of the left drive unit FL11a and the first tunable capacitor CA11, and the other one The ground terminal Tg12 is commonly used as the ground terminal of the right drive unit FL11a and the second tunable capacitor CA12. In another embodiment, a ground terminal dedicated to the first tunable capacitor CA11 is separately provided, and this is connected to the lower electrode layer 23 of the first tunable capacitor CA11 via a dedicated line. A ground terminal may be provided separately and connected to the lower electrode layer 26 of the second tunable capacitor CA12 by a dedicated line.

  In this way, the bias voltage applied to the dielectric layer 24 of the first tunable capacitor CA11 can be made different from the bias voltage applied to the dielectric layer 27 of the second tunable capacitor CA12. That is, the characteristic impedance adjustment for the first signal line SL11 side and the characteristic impedance adjustment for the second signal line SL12 side can be performed individually, so that finer characteristic impedance adjustment can be performed as a whole.

[Second Embodiment]
6 and 7 show a second embodiment of the present invention (MEMS switch). In the description here, for the sake of convenience of explanation, as in the description with reference to FIG. 1, the left, right, bottom, top, front, back and back of FIG. Indicated as right, top and bottom.

  First, the configuration of the MEMS switch SD20 will be described with reference to FIG.

  The MEMS switch SD20 shown in FIG. 6 has a multilayer structure created using a known thin film formation method. In one embodiment, the MEMS switch SD20 is configured to have a front-rear dimension of about 1.0 mm, a left-right dimension of about 1.2 mm, and a vertical dimension of about 0.5 mm.

The MEMS switch SD20 includes the MEMS switch SD10,
A point using a base BS11 ′ having a smaller left and right dimension than the base BS11. A first through hole PH1 having a smaller left and right dimension than the first through hole PH11 and the second through hole PH12.
1 'and the second through-hole PH12' are used to make the top through-line outline of the second through-hole PH12 'substantially U-shaped, and the drive unit FL11a and the hinge part FL11c on the right side of the lever FL11 are removed. The point used as the bar FL11 ′, the first electrode layer 15 provided on the right side of the base BS11, and the drive voltage input terminal Ti12a
The bias voltage input terminal 12b, the ground terminal Tg12, and the high resistance line HRL12 are eliminated, and a bias voltage input terminal Ti11c that replaces the bias voltage input terminal 12b is provided on the left side of the base BS11 ′. High resistance line HR
The configuration is different in that L12 ′ is provided on the left side of the second signal line SL12. Since the other configuration of the MEMS switch SD20 is the same as that of the MEMS switch SD10, the description thereof is omitted.

  Next, with reference to FIG. 7, the usage method and function of MEMS switch SD20 which concern on one Embodiment of this invention are demonstrated.

  In use, the MEMS switch SD20 is mounted on a circuit board or the like as shown in FIG. Further, the positive side of the first variable DC power source DC11a is connected to the drive voltage input terminal Ti11a, the positive side of the second variable DC power source DC11b is connected to the bias voltage input terminal Ti11b, and the positive side of the third variable DC power source DC11c is connected. The bias voltage input terminal Ti11c is connected, and the negative sides of these variable DC power supplies DC11a, DC11b, and DC11c are connected to the ground terminal Tg11.

  As will be described later, since the bias voltages applied to the bias voltage input terminals Ti11b and Ti11c have the same value, in one embodiment, one variable DC power supply can be shared for bias voltage application. In one embodiment, the variable DC power supply may be replaced with a DC voltage input line provided on a circuit board or the like as long as voltage application described later can be performed in the same manner.

  Further, the high-frequency signal line (input side) provided on the circuit board or the like is connected to the first signal line SL11, and the high-frequency signal line (output side) is connected to the second signal line SL12. The high frequency signal line (input side) may be connected to the second signal line SL12, and the high frequency signal line (output side) may be connected to the first signal line SL11.

  In use, a first direct-current voltage (hereinafter referred to as drive voltage) is applied from the first variable direct-current power source DC11a to the drive voltage input terminal Ti11a. Further, a DC voltage of a predetermined value (hereinafter referred to as a bias voltage) is applied from the second variable DC power supply DC11b to the bias voltage input terminal Ti11b, and the same as this from the third variable DC power supply DC11c to the bias voltage input terminal Ti11c. A value bias voltage is applied.

  The operation and effect of the MEMS switch SD20 are the same as the operation and effect of the MEMS switch SD10.

[Third Embodiment]
8 to 12 show a third embodiment of the present invention. In the description here, for the sake of convenience of explanation, as in the description with reference to FIG. 1, the left, right, bottom, top, front, back and back of FIG. Indicated as right, top and bottom.

  First, the configuration of the MEMS switch SD30 will be described with reference to FIGS.

  The MEMS switch SD30 shown in FIGS. 8 to 10 has a multilayer structure created by using a known thin film forming method. In one embodiment, the MEMS switch SD30 is configured to have a front-rear dimension of about 1.0 mm, a left-right dimension of about 1.20 mm, and a vertical dimension of about 0.5 mm.

  The MEMS switch SD30 includes a base BS31, a lever FL31, a contact electrode CT31, a first tunable capacitor CA31, a connection terminal Tca31, a second tunable capacitor CA32, a connection terminal Tca32, and a first signal line SL31. A second signal line SL32, a ground terminal Tg31, a drive voltage input terminal Ti31a, and bias voltage input terminals Ti31b and Ti31c.

The base BS 31 is made of a first base layer 31 made of Si or the like, SiO ₂ or the like, and
A first insulator layer 32 formed on the first base layer 31 made of Si or the like, and, the second base layer 33 formed on the third insulating layer 31 made of SiO ₂ or the like, and And a second insulator layer 34 formed on the second base layer 33.

  In the first base layer 31 and the first insulator layer 32, a first through hole PH31 having a substantially rectangular outline in top view is formed. Further, the second base layer 33 and the second insulator layer 34 are formed with a second through hole PH32 having a substantially U-shaped outline in top view, and the mother of the lever FL31 is formed inside the second through hole PH32. A band-shaped base layer 33a and a band-shaped insulator layer 34a serving as materials are present.

  A first electrode layer 35 made of Ti / Pt and having a substantially rectangular outline in top view is formed on the upper left surface of the base BS 31. Further, on the front upper surface and the rear upper surface of the base BS 11, a second electrode layer 36 made of Ti / Pt and having a substantially rectangular outline in top view is formed with the same thickness as the first electrode layer 35.

  The lever FL31 has a drive part FL31a, a displacement part FL31b located at the free end of the drive part FL31a, and a hinge part FL31c connecting the drive part FL31a and the displacement part FL31b.

  The drive unit FL31a uses the left part of the band-shaped base layer 33a and the band-shaped insulator layer 34a described above as its base material. On the left side portion, a third electrode layer 37 made of Ti / Pt and having a substantially rectangular outline in top view is formed continuously with the first electrode layer 35 with the same thickness as the first electrode layer 35. ing. On the third electrode layer 37, a piezoelectric layer 38 made of PZT or the like and having the same top view contour as the third electrode layer 37 is formed. Further, a fourth electrode layer 39 made of Ti / Pt and having the same top view contour as that of the piezoelectric layer 38 is formed on the piezoelectric layer 38.

  The displacement part FL31b uses the right end portion of the band-shaped base layer 33a and the band-shaped insulator layer 34a described above as its base material. On the right end portion of the strip-shaped base layer 33a and the strip-shaped insulator layer 34a, a dummy electrode layer 40 made of Ti / Pt and having a substantially rectangular outline in top view is formed with the same thickness as the third electrode layer 37. ing. On the dummy electrode layer 40, a contact electrode CT31 made of Ti / Au and having the same top view contour as the dummy electrode layer 40 is formed.

  Hinge portion FL31c uses as its base material the portion sandwiched between the left portion and the right end portion of strip-shaped base layer 33a and strip-shaped insulator layer 34a described above. By forming through holes (without reference numerals) in these base materials, the hinge portion FL31c is given flexibility to serve as a hinge.

  On the front side of the second through hole PH32 on the base BS31, a lower electrode layer 41 made of Ti / Pt and having a substantially rectangular outline in top view is formed with the same thickness as the third electrode layer 37. On the lower electrode layer 41, a dielectric layer 42 made of PZT or the like and having the same outline as the lower electrode layer 41 in a top view is formed with the same thickness as the piezoelectric layer 38. Further, an upper electrode layer 43 made of Ti / Pt and having the same top profile as the dielectric layer 42 is formed on the dielectric layer 42 with the same thickness as the fourth electrode layer 39. Here, the lower electrode layer 41, the dielectric layer 42, and the upper electrode layer 43 constitute a first tunable capacitor CA31, and the first tunable capacitor CA31 is disposed on the base BS31. Further, on the upper electrode layer 43 of the first tunable capacitor CA31, a connection terminal Tca31 made of Ti / Au and having the same top view outline as the upper electrode layer 43 is formed. As can be seen from FIG. 9 (S13), the upper surface of the connection terminal Tca31 is in close contact with and electrically connected to the lower surface of the rear portion of the first signal line SL31.

  Further, on the rear side of the second through hole PH32 on the base BS31, a lower electrode layer 44 made of Ti / Pt and having a substantially rectangular outline in top view is formed with the same thickness as the third electrode layer 37. Yes. On the lower electrode layer 44, a dielectric layer 45 made of PZT or the like and having the same outline as the lower electrode layer 44 in the top view is formed with the same thickness as the piezoelectric layer 38. Further, an upper electrode layer 46 made of Ti / Pt and having the same top view contour as the dielectric layer 45 is formed on the dielectric layer 45 with the same thickness as the fourth electrode layer 39. Here, the lower electrode layer 44, the dielectric layer 44 and the upper electrode layer 45 constitute a second tunable capacitor CA32, and the second tunable capacitor CA32 is disposed on the base BS31. Further, on the upper electrode layer 446 of the second tunable capacitor CA32, a connection terminal Tca32 made of Ti / Au and having the same top view outline as the upper electrode layer 46 is formed. As can be seen from FIG. 9 (S13), the upper surface of the connection terminal Tca31 is in close contact with and electrically connected to the lower surface of the front portion of the second signal line SL32.

  The first signal line SL31 and the second signal line SL32 are made of Ti / Au, and have a cross-sectional shape in which a flat base material is bent 90 degrees and further bent 90 degrees in the opposite direction. The lower surface of the front portion of the first signal line SL31 is connected to the upper surface of the second electrode layer 36 on the front side, and the lower surface of the rear portion of the second signal line SL32 is connected to the upper surface of the second electrode layer 36 on the rear side. Yes. Since the first signal line SL31 and the second signal line SL32 are formed so as to be line symmetric with respect to the S16-S16 line in the front-rear direction, the upper and lower surfaces of the rear portion of the first signal line SL31 and the second The upper and lower surfaces of the front portion of the signal line SL32 are flush with each other.

  As can be seen from FIG. 8, the left and right dimensions of the first signal line SL31 and the second signal line SL32 are larger than the left and right dimensions of the contact electrode CT31 and the connection terminals Tca31 and Tca32. Further, the rear part of the first signal line SL31 and the front part of the second signal line SL32 extend above the contact electrode CT31, and the first signal line SL31 and the front part are between the rear part and the front part. A gap GA is provided to make the second signal line SL32 non-conductive. Further, a gap (no symbol) having a predetermined vertical dimension is formed between the lower surface of the rear portion of the first signal line SL31 and the lower surface of the front portion of the second signal line SL32 and the contact electrode CT31. .

  The ground terminal Tg31 is made of Ti / Au, and is formed on the first electrode layer 35 so that the outline in top view is substantially rectangular. The drive voltage input terminal Ti31a is made of Ti / Au, and is formed at the left end on the fourth electrode layer 39 of the drive unit FL31a so that the outline in top view is substantially rectangular. The bias voltage input terminal Ti31b is made of Ti / Au, and is formed on the upper surface on the left front side of the base BS31 so that the outline in top view is substantially rectangular and is aligned with the ground terminal Tg31 at an interval. The bias voltage input terminal Ti31c is made of Ti / Au, and is formed on the upper left rear surface of the base BS11 so that the outline in top view is substantially rectangular and aligned with the drive voltage input terminal Ti31a. Yes.

  The bias voltage input terminal Ti31b and the front second electrode layer 36 are connected by a high resistance line HRL31, and the bias voltage input terminal Ti31c and the rear second electrode layer 36 are connected by a high resistance line HRL32. ing. These high resistance lines HRL31 and HRL32 are made of a high resistance material such as TaN, and have higher resistivity than the first signal line SL31 and the second signal line SL32.

  Next, with reference to FIGS. 11 and 12, a method of using the MEMS switch SD30, functions, and the like will be described.

  In use, the MEMS switch SD30 is mounted on a circuit board or the like as shown in FIG. The positive side of the first variable DC power source DC31a is connected to the drive voltage input terminal Ti31a, the positive side of the second variable DC power source DC31b is connected to the bias voltage input terminal Ti31b, and the positive side of the third variable DC power source DC31c is connected. The bias voltage input terminal Ti31c is connected, and the negative sides of these variable DC power supplies DC31a, DC31b and DC31c are connected to the ground terminal Tg31.

  Although three variable DC power sources DC31a, DC31b, and DC31c are shown in the drawing, the bias voltages applied to the bias voltage input terminals Ti31b and Ti31c have the same value as will be described later. The variable DC power supply can be shared for driving voltage application. In one embodiment, the variable DC power supply may be replaced with a DC voltage input line provided on a circuit board or the like as long as voltage application described later can be performed in the same manner.

  Further, the high-frequency signal line (input side) provided on the circuit board or the like is connected to the first signal line SL31, and the high-frequency signal line (output side) is connected to the second signal line SL32. The high frequency signal line (input side) may be connected to the second signal line SL32, and the high frequency signal line (output side) may be connected to the first signal line SL31.

  In use, a direct current voltage (hereinafter referred to as drive voltage) of a predetermined value is applied from the first variable DC power source DC31a to the drive voltage input terminal Ti31a. Also, a DC voltage of a predetermined value (hereinafter referred to as a bias voltage) is applied from the second variable DC power source DC31b to the bias voltage input terminal Ti31b, and the same as this from the third variable DC power source DC31c to the bias voltage input terminal Ti31c. A value bias voltage is applied.

  The drive voltage applied to the drive voltage input terminal Ti31a is applied to the piezoelectric layer 38 of the drive unit FL31a through the fourth electrode layer 39 constituting the drive unit FL31a of the lever FL31.

  As a result, as shown in FIG. 12, the piezoelectric layer 38 constituting the drive unit FL31a contracts due to the piezoelectric effect. Due to the contraction of the piezoelectric layer 38, the hinge part FL31c side of the drive part FL31a is warped upward, and the warp rise displaces the displacement part FL31b of the lever FL31, and the upper displacement causes the upper surface of the contact electrode CT31 to be the first signal. The lower surface of the rear portion of the line SL31 and the lower surface of the front portion of the second signal line SL32 are contacted, and the contact causes both signal lines SL31 and SL32 to be in a conductive state via the contact electrode CT31. That is, the high-frequency signal input to the first signal line SL31 is output from the second signal line SL32 via the first signal line SL31, the contact electrode CT31, and the second signal line SL32.

On the other hand, the bias voltage applied to the bias voltage input terminal Ti31b passes through the high resistance line HRL31, the front second electrode layer 36, the first signal line SL31, the connection terminal Tca31, and the upper electrode layer 43 of the first tunable capacitor CA31. Applied to the dielectric layer 42 of the first tunable capacitor CA31. The bias voltage applied to the bias voltage input terminal Ti31c is the high resistance line HRL32, the second electrode layer 36 on the rear side, the second signal line SL32, the connection terminal Tca32, and the upper electrode layer 46 of the second tunable capacitor CA32. Through the dielectric layer 45 of the second tunable capacitor CA32.

  As a result, the relative dielectric constants of the dielectric layers 42 and 45 of both tunable capacitors CA31 and CA32 change, and the capacitances of both tunable capacitors CA31 and CA31 change due to the change, and the change causes the characteristic impedance of the MEMS switch SD30. Changes.

  That is, even if the characteristic impedance (for example, 50Ω or 75Ω) of the MEMS switch SD30 mounted on the circuit board or the like is disturbed by an external influence, the capacitances of both the tunable capacitors CA31 and CA31 are set so as to cancel the disturbance. If the bias voltage is changed, the characteristic impedance can be adjusted to an optimum value.

  Next, effects obtained by the MEMS switch SD30 according to the embodiment of the present invention will be described.

  (1) In the MEMS switch SD30 according to the embodiment of the present invention, the capacitance of both the tunable capacitors CA31 and CA31 is changed by the bias voltage so as to cancel the disturbance of the characteristic impedance that occurs during use. Since the characteristic impedance can be adjusted, an optimum characteristic impedance can be ensured for the MEMS switch SD30, thereby avoiding deterioration in characteristics such as an increase in transmission loss and a decrease in isolation due to the disturbance of the characteristic impedance.

  (2) In the MEMS switch SD30 according to the embodiment of the present invention, the first tunable capacitor CA31 is provided corresponding to the first signal line SL31, and the first tunable capacitor CA31 is provided corresponding to the second signal line SL32. Since the two tunable capacitors CA32 are provided, the desired characteristic impedance adjustment is effectively performed on the entire line (the first signal line SL31, the contact electrode CT31, and the second signal line SL32) through which the high-frequency signal flows. Can do.

  (3) In the MEMS switch SD30, the first tunable capacitor CA31 and the second tunable capacitor CA32 are disposed on the base BS31, and the upper surface of the connection terminal Tca31 on the first tunable capacitor CA31 is the first. One signal line SL31 is in contact with and electrically connected to the lower surface of the rear portion, and the upper surface of the connection terminal Tca32 on the second tunable capacitor CA32 is in contact with the lower surface of the front portion of the second signal line SL32. Since it is electrically connected, the first tunable capacitor CA31 and the connection terminal Tca31 can play the role of a column that supports and holds the rear portion of the first signal line SL31, and the second tunable The capacitor CA32 and the connection terminal Tca32 support and hold the front portion of the second signal line SL32. It is possible to play a role of the post.

  In this way, since the rear portion of the first signal line SL31 and the front portion of the second signal line SL32 that are in contact with the contact electrode CT31 can be reinforced, the contact electrode CT31 repeatedly contacts and cancels these portions. However, it is difficult for the portion to be deformed, and contact failure that may occur due to the deformation can be prevented.

  (4) In the MEMS switch SD30 according to the embodiment of the present invention, the bias voltage applied to the bias voltage input terminal Ti31b is applied to the dielectric layer 42 of the first tunable capacitor CA31 via the high resistance line HRL31. In addition, since the bias voltage applied to the bias voltage input terminal Ti31c is applied to the dielectric layer 45 of the second tunable capacitor CA32 via the high resistance line HRL32, the high resistance is applied from the first signal line SL31. A high frequency signal leaks to the line HRL31 side and a high frequency signal leaks from the second signal line SL32 to the high resistance line HRL32 side. Thereby, characteristic deterioration of the high frequency signal which flows via 1st signal track | line SL31, contact electrode CT31, and 2nd signal track | line SL32 can be prevented.

  (5) The MEMS switch SD30 according to an embodiment of the present invention can be regarded as a device having a filter function. That the characteristic impedance can be made variable means that the filter function can be made variable. Since the two tunable capacitors CA31 and CA32 provided on both sides of the contact electrode CT31 are connected to the ground, the first signal line SL31 and the second signal line SL32 through which the high-frequency signal passes through the tunable capacitors CA31 and CA32. A low-pass filter can be configured by combining with an inductance component. If the capacitances of the tunable capacitors CA31 and CA32 are changed, the cut-off frequency can be adjusted.

  As MEMS switch SD30 which concerns on one Embodiment of this invention, the dielectric material layer which comprises the piezoelectric material layer 38 which comprises the drive part FL31a, the dielectric material layer 42 which comprises 1st tunable capacitor CA31, and 2nd tunable capacitor CA32 The body layer 45 is formed of PZT, but instead of PZT, lead zirconate, lead titanate, lead magnesium niobate, lead nickel niobate, barium titanate, sodium bismuth titanate, niobate Potassium sodium, strontium bismuth tantalate, or the like can be used.

Further, in the MEMS switch SD30 according to the embodiment of the present invention, the first electrode layer 35, the second electrode layer 36, the third electrode layer 37 and the fourth electrode layer 39 constituting the driving unit FL11a, and the dummy electrode layer 40. , Contact electrode CT31, lower electrode layer 41 and upper electrode layer 43 constituting the first tunable capacitor CA31, connection terminal Tca31, lower electrode layer 44 and upper electrode layer 46 constituting the second tunable capacitor CA32, connection terminal Tca32 The first signal line SL31, the second signal line SL32, the ground terminal Tg31, the drive voltage input terminal Ti31a, and the bias voltage input terminals Ti31b and Ti31c are respectively Ti / Pt or Ti in which a Ti layer and a Pt layer are stacked. It consists of either Ti / Au which laminated | stacked the layer and Au layer. In another embodiment of the present invention, any one of a Cr layer, a Zr layer, a TiN layer, or a TiO ₂ layer can be used instead of the Ti layer of Ti / Pt and / or Ti / Au. Further, any one of an Au alloy layer, a Cu layer, and an Ag layer can be used instead of the Ti / Pt Pt layer. Furthermore, any one of an Au alloy layer, a Cu layer, and an Ag layer can be used instead of the Ti / Au Au layer. In another embodiment of the present invention, a single layer composed of a Pt layer, an Au layer, an Au alloy layer, a Cu layer, or an Ag layer may be used instead of Ti / Pt or Ti / Au. In one embodiment of the present invention, the thickness of the Ti layer, Cr layer, Zr layer, TiN layer, or TiO ₂ layer can be 1 nm to 100 nm, and the Pt layer, Au layer, Au alloy layer, Cu The film thickness of the layer or the Ag layer can be 0.1 μm to 30 μm. As will be apparent to those skilled in the art, the materials that make up each element included in the MEMS switch SD30 according to various embodiments of the present invention are not limited to those explicitly set forth herein, and are within the scope of the present invention. As long as it does not deviate from the above, it can be changed as appropriate.

  As the MEMS switch SD30 according to the embodiment of the present invention, one ground terminal Tg31 is shared as the ground terminal of the drive unit FL31a, the first tunable capacitor CA31, and the second tunable capacitor CA32. A ground terminal dedicated to the tunable capacitor CA31 is separately provided, and this is connected to the lower electrode layer 41 of the first tunable capacitor CA31 by a dedicated line, and a ground terminal dedicated to the second tunable capacitor CA32 is separately provided. The lower electrode layer 44 of the two tunable capacitor CA32 may be connected by a dedicated line.

  In this way, the bias voltage applied to the dielectric layer 42 of the first tunable capacitor CA31 can be made different from the bias voltage applied to the dielectric layer 45 of the second tunable capacitor CA32. That is, the characteristic impedance adjustment for the first signal line SL31 side and the characteristic impedance adjustment for the second signal line SL32 side can be performed individually, so that finer characteristic impedance adjustment can be performed as a whole.

  SD10 ... MEMS switch, BS11 ... base, FL11 ... lever, FL11a ... driving unit, FL11b ... displacement unit, FL11c ... hinge part, CT11 ... contact electrode, CA11 ... first tunable capacitor, Tca11 ... connection electrode, CA12 ... second Tunable capacitor, Tca12 ... connection electrode, SL11 ... first signal line, SL12 ... second signal line, Tg11, Tg12 ... ground terminal, Ti11a, Ti12a ... drive voltage input terminal, Ti11b, Ti12b ... bias voltage input terminal, HRL11, HRL12 ... high resistance line, SD20 ... MEMS switch, BS11 '... base, FL11' ... lever, Ti11c ... bias voltage input terminal, HRL12 '... high resistance line, SD30 ... MEMS switch, BS31 ... base, FL31 ... lever, F 31a ... Drive unit, FL31b ... Displacement unit, FL31c ... Hinge, CT31 ... Contact electrode, CA31 ... First tunable capacitor, Tca31 ... Connection electrode, CA32 ... Second tunable capacitor, Tca32 ... Connection electrode, SL31 ... First Signal line, SL32, second signal line, Tg31, ground terminal, Ti31a, drive voltage input terminal, Ti31b, Ti31c, bias voltage input terminal, HRL31, HRL32, high resistance line.

Claims (4)

A contact electrode is brought into contact with the first signal line and the second signal line, thereby bringing the first signal line and the second signal line into a conductive state via the contact electrode, and the first signal line and the second signal line. And a MEMS switch that brings the first signal line and the second signal line into a non-conductive state by making the contact electrode non-contact,
A first tunable capacitor provided corresponding to the first signal line;
A second tunable capacitor provided corresponding to the second signal line;
A first bias voltage input terminal for applying a bias voltage to the dielectric layer of the first tunable capacitor through one electrode layer side of the first signal line and the first tunable capacitor;
A second bias voltage input terminal for applying a bias voltage to the dielectric layer of the second tunable capacitor through one electrode layer side of the second signal line and the second tunable capacitor;
Is provided. The first tunable capacitor and the second tunable capacitor are disposed on a displacement portion of a lever on which the contact electrode is disposed;
When the contact electrode comes into contact with the first signal line and the second signal line due to a predetermined direction displacement of the displacement portion, one electrode layer side of the first tunable capacitor comes into contact with the first signal line. Electrically connect,
2. The MEMS switch according to claim 1, wherein one electrode layer side of the second tunable capacitor is in contact with and electrically connected to the second signal line. 3. The first tunable capacitor and the second tunable capacitor are disposed on a base provided with the first signal line and the second signal line;
One electrode layer side of the first tunable capacitor is electrically connected to the first signal line,
The MEMS switch according to claim 1, wherein one electrode layer side of the second tunable capacitor is electrically connected to the second signal line. A first bias voltage input terminal for the first tunable capacitor is connected to the first signal line via a high-resistance line having a higher resistivity than the first signal line;
2. The second bias voltage input terminal for the second tunable capacitor is connected to the second signal line through a high resistance line having a higher resistivity than the second signal line. The MEMS switch in any one of -3.

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