KR100571778B1 - Radio frequency micro electro mechanical system switch and fabrication method thereof - Google Patents

Abstract

The RF MEMS switch according to the present invention includes a substrate, at least one signal line installed on the substrate, at least one electrostatic drive unit installed on the substrate, at least one post installed on the substrate and grounded to ground, at least one pivot grounded to ground, and And a conductive switch pad having an opening for receiving the post and supported by the pivot so as to be in contact with or spaced from the signal line according to the operation of the electrostatic driver. The method of manufacturing the RF MEMS switch of the present invention comprises the steps of preparing a silicon substrate, forming a signal line, an electrostatic driving electrode, and ground on the silicon substrate, forming a pivot and a conductive switch pad on the silicon substrate, and on the silicon substrate And forming a post that connects to ground and supports the conductive switch pad to seesaw with respect to the pivot. The RF MEMS switch of the present invention has a seesaw motion structure that operates simply without using a coupling, deformation, and recovery structure, thereby providing an effect of minimizing driving voltage.

RF, MEMS, Switch, Seesaw, Pad, Post

Description

RF MEMS switch and its manufacturing method {Radio frequency micro electro mechanical system switch and fabrication method

1 is a schematic perspective view of an RF MEMS switch according to a first preferred embodiment of the present invention.

FIG. 2 is a partial front sectional view of the RF MEMS switch shown in FIG. 1. FIG.

3A-3G are process diagrams illustrating a manufacturing process of an RF MEMS switch taken along line I-I of FIG.

4 is a schematic perspective view of an RF MEMS switch according to a second preferred embodiment of the present invention.

5 is a perspective view illustrating the structure of a signal line, an electrostatic driver, a balanced driver, a pad support post, and a ground of the RF MEMS switch shown in FIG. 4;

FIG. 6 is a perspective view illustrating a structure of a conductive switch pad of the RF MEMS switch shown in FIG. 4. FIG.

7A-7F are process diagrams illustrating the fabrication process of an RF MEMS switch taken along line II-II of FIG. 4.

* Description of the symbols for the main parts of the drawings *

10. 10 ': switch 11: board

12a and 12b: signal lines 13a and 13b: electrostatic driving unit

15, 15 ': ground 16, 16': conductive switch pad

18: pad support posts 20, 20a ', 20b': pivot

31, 32, 31 ', 33', 34 ': Sacrifice 32, 32': pivot hole

33, 35 ': pad support post hole 34: wire support post hole

35: wire hole

 The present invention relates to an RF switch, and more particularly, to a radio frequency (RF) switch using MEMS (Micro Electro Mechanical System) technology and a method of manufacturing the same.

In general, RF MEMS switches are often used in the form of bridges or cantilever beams. Such RF MEMS switches are designed to operate at low spring constants to lower drive voltages and switch at higher speeds, which results in weak structures, particularly coupling sites, and thus poor manufacturing and operational reliability. In addition, since the RF MEMS switch has a mechanism of repeating the deforming and restoring operation during operation, stress may accumulate in the deformed portion, and as a result, the performance and the service life are deteriorated. In addition, according to published patent documents and papers, these RF MEMS switches are known to be difficult to operate at a driving voltage of 10V or less.

In order to solve this problem, a new concept of RF MEMS switch has been developed and released that eliminates the mechanism of repeating the deformation and restoration operation during the last three years. Such RF MEMS switches are disclosed in US Pat. Nos. 6,294,847, 6,143,997, and 6,489,857.

The RF MEMS switch of US Pat. No. 6,294,847 uses two capacitors that drive an isolation operation mounted on the surface of the substrate. However, this RF MEMS switch has a disadvantage in that a relatively large driving force is required to overcome friction or collision during operation of the isolation operation part.

The RF MEMS switches of US Pat. Nos. 6,143,997 and 6,489,857 have switch pads actuated by top and bottom drive electrodes, and posts to guide the switch pads up and down. However, since these RF MEMS switches are made by the post through the contacts that are not fixed to the switch pad, electrical disconnection or poor connection may occur. In addition, these RF MEMS switches, due to manufacturing tolerances between the posts and the post openings of the switch pads, may cause jams when the switch pads are moved up and down, thereby degrading operational reliability.

The present invention has been made to solve the above problems, the main object of the present invention is to provide a seesaw motion structure that is simple to operate without using a coupling, deformation and recovery structure RF MEMS switch that can minimize the driving voltage and The manufacturing method is provided.

Another object of the present invention is to provide an RF MEMS switch and a method of manufacturing the same, which can remarkably improve the switching speed while eliminating the problem of requiring a low modulus by not using a deformation and restoring structure.

It is still another object of the present invention to provide an RF MEMS switch having a simple and robust structure and a method of manufacturing the same in order to improve manufacturing reliability.

In order to achieve the object of the present invention as described above, one embodiment of the present invention is a substrate, at least one signal line provided on the substrate, at least one electrostatic drive installed on the substrate, the substrate is installed and grounded to ground An RF MEMS switch having at least one post, at least one pivot grounded to ground, and an opening for receiving the post, the conductive switch pad being supported by the pivot so as to be in contact with or spaced from the signal line according to the operation of the electrostatic drive unit. to provide.

In a preferred embodiment, the post has a cap formed on the top end to limit the movement of the conductive switch pad.

The pivot may be integrally formed with one of the conductive switch pad, ground, and the substrate.

The conductive switch pad may include a plurality of etching holes to facilitate etching of the lower sacrificial layer during manufacturing.

The RF MEMS switch of the present invention may further include a conductive wire electrically connecting between the conductive switch pad and the ground.

In addition, the RF MEMS switch of the present invention may further include at least one balance drive to maintain the conductive switch pad at a predetermined interval without contacting the signal line.

According to another embodiment of the present invention, the present invention provides a method of preparing a silicon substrate, forming a signal line, an electrostatic driving electrode, and a ground on the silicon substrate, forming a pivot and a conductive switch pad on the silicon substrate, and A method of manufacturing an RF MEMS switch is provided that includes forming a first post on a substrate that connects to ground and supports a conductive switch pad to seesaw with respect to the pivot.

Forming the signal line, the electrostatic driving electrode, and the ground comprises forming a first metal layer on the silicon substrate, and patterning the first metal layer to form the signal line, the electrostatic driving electrode, and the ground. In this case, when the balanced driving electrode is formed, the operation of forming the signal line, the electrostatic driving electrode, and the ground further includes forming the balanced driving electrode by patterning the balanced driving electrode.

The forming of the pivot and the conductive switch pad may include forming a first sacrificial layer on the substrate on which the signal line, the electrostatic driving electrode, and the ground are formed, selectively etching the first sacrificial layer to form the pivot hole, Depositing a second metal layer on the formed first sacrificial layer, and patterning the second metal layer to form a conductive switch pad having a pivot.

The forming of the first post may include forming a second sacrificial layer on the first sacrificial layer on which the conductive switch pad is formed, selectively etching the first and second sacrificial layers to form a post hole, and forming the post hole. Depositing a third metal layer over the second sacrificial layer, patterning the third metal layer to form a first post, and removing the first and second sacrificial layers.

At this time, in the case of forming the conductive wire, the operation of forming the post hole further forms a conductive wire / post hole for the conductive wire and the second post supporting the conductive wire, and the operation of forming the first post And patterning the conductive wires and the second posts supporting the conductive wires.

Optionally, forming the pivot and the conductive switch pad may include forming a first sacrificial layer on the substrate on which the signal line, the electrostatic driving electrode, and the ground are formed, selectively etching the first sacrificial layer to form the pivot hole, Depositing a second metal layer on the first sacrificial layer on which the pivot hole is formed, patterning the second metal layer to form the pivot, and forming a second sacrificial layer on the pivoted first sacrificial layer, second sacrifice Depositing a third metal layer over the layer, and patterning the third metal layer to form a conductive switch pad. In this case, the forming of the first post may include forming a third sacrificial layer on the second sacrificial layer on which the conductive switch pad is formed, and selectively etching the first, second and third sacrificial layers to form a post hole. Depositing a fourth metal layer over the third sacrificial layer on which the post holes are formed, patterning the fourth metal layer to form the first post, and removing the first, second and third sacrificial layers. .

Hereinafter, an RF MEMS switch and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

(Example 1)

1, 2 and 3G, an RF MEMS switch 10 according to a first preferred embodiment of the present invention is illustrated.

The RF MEMS switch 10 of this embodiment includes a substrate 11, first and second signal lines 12a and 12b provided on the substrate 11 at both sides of the substrate 11, and first and second on the substrate 11. First and second electrostatic driving parts 13a and 13b provided inside the signal lines 12a and 12b, pad support posts 18 protruding perpendicularly from the ground 15 provided on the substrate 11, and provided on the substrate 11 A pivot 20 movably grounded to ground 15, and an opening 17 for receiving the pad support post 18 and according to the operation of the first and second electrostatic drivers 13a, 13b. Or a conductive switch pad 16 supported on the substrate 11 by the pivot 20 to be in contact with or spaced apart from the second signal line 12a or 12b.

The first and second electrostatic drivers 13a, 13b respectively apply an electrostatic force to one of the corresponding ends of the conductive switch pads 16, i.e., the first and second ends 16a, 16b when a voltage is applied. It consists of a metal electrode that can be attracted to.

The pad support post 18 has a rectangular pillar shape, and a cap 19 is formed at the upper end to limit the vertical movement of the conductive switch pad 16.

The pivot 20 is integrally formed with the conductive switch pad 16 so as to be grounded to be movable to the ground 15 at the lower surface of the conductive switch pad 16.

The conductive switch pad 16 is supported by the opening 17 for receiving the pad support post 18 so as to be able to seesaw the left and right and up and down the pad support post 18 while being able to move to the ground 15. It is grounded to ground 15 through grounded pivot 20.

Therefore, as shown in FIG. 2, when a voltage is applied to one of the first and second electrostatic driving units 13a and 13b, for example, the second electrostatic driving unit 13b, the corresponding conductive switch pad 16 is applied. The second end 16b of) is drawn and tilted in the form of a seesaw and "on" in contact with the corresponding second signal line 12b.

As such, the second signal line 12b that is 'on' in contact with the end 16b of the conductive switch pad 16 has a large capacitance of a variable capacitor (not shown) attached to the second signal line 12b. As a result, most of the signals flowing to the second signal line 12b are bypassed to the ground 15.

In contrast, the first signal line 12a, which is 'off' away from the first end 16a of the conductive switch pad 16, has a very small capacitance of the capacitor so that most of the signal is transmitted along the first signal line 12a.

In addition, the conductive switch pad 16 may include a plurality of etching holes 41 to facilitate etching of the lower sacrificial layer, as described below.

In order to further secure the electrical connection between the conductive switch pad 16 and the ground 15, the RF MEMS switch 10 of the present invention further includes a conductive wire 22.

The conductive wire 22 is formed of a bent wire extending from the upper end of the wire support post 21 formed perpendicular to the ground 15 to contact the upper surface of the conductive switch pad 16.

The manufacturing method of the RF MEMS switch 10 according to the first embodiment of the present invention configured as described above will be described in detail with reference to FIGS. 3A to 3G.

First, as shown in FIG. 3A, after the silicon substrate 11 is prepared, a first metal layer (not shown) made of a metal such as Al, Cu, or the like is deposited on the substrate 11 by a method such as sputtering or vacuum deposition. Is formed.

Then, the first and second signal lines 12a and 12b, the first and second electrostatic driving electrodes 13a and 13b in a photolithography process of applying a photoresist on the first metal layer and exposing and developing with a photo mask, and A signal line / electrode / ground pattern having a pattern of ground 15 is formed.

After the signal line / electrode / ground pattern is formed, the first metal layer is patterned by dry or wet etching using the signal line / electrode / ground pattern as an etching mask, and as a result, the first and second signal lines 12a on the substrate 11. 12b), first and second electrostatic driving electrodes 13a and 13b, and ground 15 are formed.

In this case, the process of patterning the first metal layer to form the first and second signal lines 12a and 12b, the first and second electrostatic driving electrodes 13a and 13b, and the ground 15 may be performed through a photolithography process. Although it has been described that the formed signal line / electrode / ground pattern is used, other methods such as laser trimming may be used without using the signal line / electrode / ground pattern.

Thereafter, the silicon substrate, which is subsequently removed by an etching process, on the substrate 11 on which the first and second signal lines 12a and 12b, the first and second electrostatic driving electrodes 13a and 13b, and the ground 15 are formed. A first sacrificial layer 31 made of a material such as porous silicon having an etching selectivity higher than that of (11) is formed. The thickness of the first sacrificial layer 31 is set to be equal to or slightly higher than the height of the pivot 20 of the switch pad 16 formed later on the first sacrificial layer 31.

After the first sacrificial layer 31 is formed, a pivot hole pattern (not shown) having a pattern of the pivot holes 32 is formed in the first sacrificial layer 31 by a photolithography process, and the first sacrificial layer 31 is formed. ) Is etched the pivot hole pattern with an etch mask. As a result, as shown in FIG. 3B, a pivot hole 32 is formed in the first sacrificial layer 31.

Subsequently, a second metal layer (not shown) made of a metal such as Al and Cu to form the pivot 20 and the conductive switch pad 16 is formed on the front surface of the first sacrificial layer 31 on which the pivot hole 32 is formed. After the deposition, the second metal layer is patterned by a method of etching using a switch pad pattern (not shown) formed on the second metal layer by a photolithography process or by a laser trimming method. In this case, the switch pad pattern includes a plurality of patterns of the etching holes 41 to be easily removed when the first sacrificial layer 31 is later removed by an etching process.

As a result, as shown in FIG. 3C, the conductive switch pad 16 having the etching hole 41 and the pivot 20 is integrally formed on the first sacrificial layer 31.

Thereafter, as shown in FIG. 3D, a second sacrificial layer 32 is formed on the entire surface of the first sacrificial layer 31 on which the conductive switch pads 16 are formed, and then a photo is formed on the second sacrificial layer 32. The pad support post hole 33, the wire support post hole 34, and the wire hole 35 for forming the pad support post 18, the wire support post 21, and the conductive wire 22, respectively, in the lithography process. A post / wire hole pattern (not shown) having a pattern of) is formed.

Subsequently, when the first sacrificial layer 31 etches the post / wire hole pattern with an etching mask, as shown in FIG. 3E, the pad support post holes 33 are formed in the first and second sacrificial layers 31 and 32. , A wire support post hole 34, and a wire hole 35 are formed.

Then, the pad support post 18, the wire support post 21, and the pad support post hole 33, the wire support post hole 34, and the front of the second sacrificial layer 32 on which the wire holes 35 are formed. And a third metal layer (not shown) made of a metal such as Al and Cu to form the conductive wire 22 is deposited, and the third metal layer is a post / wire pattern (not shown) formed on the third metal layer by a photolithography process. Patterning) using a method of etching, or by laser trimming.

As a result, as shown in FIG. 3F, the cap 19 is disposed on the pad support post hole 33, the wire support post hole 34, and the wire hole 35 and the second sacrificial layer 32 in the vicinity thereof. The pad support post 18 which has the, the wire support post 21, and the conductive wire 22 are formed, respectively.

Thereafter, as shown in FIG. 3G, when the first and second sacrificial layers 31 and 32 are etched and removed with an etchant having an etching selectivity with respect to the first and second sacrificial layers 31 and 32, The manufacture of the RF MEMS switch 10 of the first embodiment of the present invention is terminated.

(Example 2)

4, 5, 6 and 7F, an RF MEMS switch 10 'in accordance with a second preferred embodiment of the present invention is illustrated. For convenience of description, the same components as the RF MEMS switch 10 of the first embodiment described with reference to FIGS. 1, 2, and 3G will be described with the same reference numerals.

The RF MEMS switch 10 'of this embodiment comprises a substrate 11, first and second signal lines 12a and 12b provided on the substrate 11 on both sides of the substrate 11, and first and second on the substrate 11; The pad support posts 18 and the substrate 11 of the first and second electrostatic driving units 13a and 13b provided inside the two signal lines 12a and 12b and the ground 15 'formed on the substrate 11 perpendicular to the ground 11'. First and second pivots 20a 'and 20b' installed in the ground 15 'and having an opening 17' for accommodating the pad support posts 18, and the first and second electrostatic drives 13a. And conductive switch pads 16 'supported by the first and second pivots 20a' and 20b 'to be in contact with or spaced apart from the first or second signal lines 12a or 12b in accordance with the operation of 13b. First and second to allow the conductive switch pads 16 'to be held at predetermined intervals without contacting the first and second signal lines 12a and 12b when the first and second electrostatic driving units 13a and 13b do not operate. 2 equilibrium And a East (24a, 24b).

The first and second electrostatic drivers 13a and 13b respectively apply electrostatic force to one of the corresponding ends of the conductive switch pads 16 ', that is, the first and second ends 16a' and 16b ', when a voltage is applied. It consists of a metal electrode that can be attracted to.

The pad support post 18 has a rectangular pillar shape, and forms a cap 19 at the upper end to limit the movement of the conductive switch pad 16 '.

As shown in FIG. 5, the first and second pivots 20a 'and 20b' are integrally connected to the fork-shaped ground 15 'and grounded. Optionally, the first and second pivots 20a 'and 20b' are only grounded to the ground 15 'and may be installed on the substrate 11.

The conductive switch pad 16 ′ is supported by the opening 17 ′ (FIG. 6) for accommodating the pad support post 18 to the pad support post 18 so as to be able to seesaw up and down and up and down, and the ground 15. Is grounded to ground 15 'via first and second pivots 20a' and 20b 'installed at').

Therefore, as shown in FIG. 4, when a voltage is applied to one of the first and second electrostatic drivers 13a and 13b, for example, the second electrostatic driver 13b, the corresponding conductive switch pad 16 ′ is applied. The second end 16b ') is drawn and tilted in the form of a seesaw and "on" in contact with the corresponding second signal line 12b.

As such, the second signal line 12b that is 'on' in contact with the second end 16a 'of the conductive switch pad 16' may include a capacitor of a variable capacitor (not shown) attached to the second signal line 12b. The capacitance becomes large, whereby most of the signal flowing to the second signal line 12b is bypassed to the ground 15 '.

In contrast, the first signal line 12a 'off' away from the first end 16a 'of the conductive switch pad 16' has a very small capacitance of the capacitor so that most of the signal is along the first signal line 12a. Is sent.

As shown in Fig. 5, the first and second balanced drives 24a and 24b are each composed of electrodes disposed between the fork-type ground 15 ', and the first and second electrostatic drives 13a and 13b. The first and second end portions 16a 'and 16b' of the conductive switch pad 16 'do not contact the corresponding first and second signal lines 12a and 12b when a voltage is not applied thereto. To be maintained.

A method of manufacturing the RF MEMS switch 10 'according to the second embodiment of the present invention configured as described above will be described in detail with reference to FIGS. 7A to 7F.

First, as shown in FIG. 7A, after the silicon substrate 11 is prepared, the first and second signal lines 12a and 12b are disposed on the silicon substrate 11 in the same manner as the RF MEMS switch 10 of the first embodiment. The first and second electrostatic driving electrodes 13a and 13b, the first and second balanced driving electrodes 24a and 24b and the ground 15 ′ are formed.

Next, a substrate on which the first and second signal lines 12a and 12b, the first and second electrostatic driving electrodes 13a and 13b, the first and second balanced driving electrodes 24a and 24b and the ground 15 are formed. A first sacrificial layer 31 ′ formed of a material such as porous silicon having an etching selectivity higher than that of the silicon substrate 11 is formed on (11). At this time, the thickness of the first sacrificial layer 31 'coincides with the height of the first and second pivots 20a' and 20b 'of the switch pad 16' formed later on the first sacrificial layer 31 '. Is set to.

After the first sacrificial layer 31 'is formed, the pattern of the pivot holes 32' for forming the first and second pivots 20a 'and 20b' on the first sacrificial layer 31 'by a photolithography process. A pivot hole pattern (not shown) is formed, and the first sacrificial layer 31 'is formed by using the pivot hole pattern as an etch mask to form a pivot hole 32' which opens a part of the ground 15 '. Etched.

Subsequently, on the front surface of the first sacrificial layer 31 'on which the pivot hole 32' is formed, a second metal layer made of metal such as Al and Cu to form the first and second pivots 20a 'and 20b'. And the second metal layer is patterned by a method of etching a conductive pivot pattern (not shown) formed on the second metal layer by a photolithography process or by a laser trimming method.

As a result, as shown in FIG. 7B, the first and second pivots 20a 'and 20b are integrally connected to the ground 15' on the pivot hole 32 'and the first sacrificial layer 31' around it. ') Is formed.

Thereafter, a second sacrificial layer 33 'is formed on the entire surface of the first sacrificial layer 31' on which the first and second pivots 20a 'and 20b' are formed, and then on the second sacrificial layer 33 '. A third metal layer (not shown) made of a metal such as Al and Cu to form the conductive switch pad 16 'is formed.

Subsequently, the third metal layer is patterned by a method of etching a switch pad pattern (not shown) formed on the third metal layer by a photolithography process or by a laser trimming method.

As a result, as shown in Fig. 7C, a conductive switch pad 16 'having an opening 17' is formed on the second sacrificial layer 33 '.

Thereafter, a third sacrificial layer 34 'is formed on the second sacrificial layer 33' on which the conductive switch pad 16 'is formed, and then a pad support post hole is formed on the third sacrificial layer 34' by a photolithography process. A post hole pattern (not shown) having a pattern of 35 'is formed.

Subsequently, when the first, second and third sacrificial layers 31 ', 33', 34 'are etched with the post hole pattern by using an etching mask, the first, second and third sacrificial layers 31', 33 ', 34 ', a pad support post hole 35' for opening a part of the ground 15 'is formed.

Next, a fourth metal layer (not shown) made of a metal such as Al and Cu to form the pad support post 18 is formed on the front surface of the third sacrificial layer 34 'on which the pad support post hole 35' is formed. The fourth metal layer is deposited by a method of etching a pad support post pattern (not shown) formed on the fourth metal layer by a photolithography process or by a laser trimming method.

As a result, as shown in FIG. 7E, the pad support post 18 having the cap 19 is formed on the pad support post hole 35 'and the third sacrificial layer 34' around the pad support post hole 35 '.

Thereafter, as shown in FIG. 7F, the first, second and third sacrificial layers (eg, etching liquids having etching selectivity with respect to the first, second and third sacrificial layers 31 ′, 33 ′, and 34 ′) are formed. 31 ', 33', and 34 'are etched and removed, the manufacture of the RF MEMS switch 10' of the second embodiment of the present invention is terminated.

As described above, it can be seen that the RF MEMS switch of the present invention and a method of manufacturing the same provide an effect of minimizing driving voltage by providing a seesaw motion structure that operates simply without using a coupling, deformation, and recovery structure. .

In addition, since the RF MEMS switch of the present invention does not use the elastic deformation of the structure during operation, it is possible to remarkably improve the switching speed while eliminating the problem of requiring a low elastic modulus.

In addition, the RF MEMS switch of the present invention and a manufacturing method thereof can improve manufacturing reliability.

Provide a simple and robust structure to help.

In the above, certain preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the above-described embodiments, and any person having ordinary skill in the art to which the present invention pertains without departing from the spirit and spirit of the present invention claimed in the claims may make various modifications and variations. It will be possible.

Claims (14)

Board; At least one signal line disposed on the substrate; At least one electrostatic driver installed on the substrate; At least one post mounted to the substrate and grounded to ground; At least one pivot grounded to the ground; And And an electroconductive switch pad having an opening for receiving the post and supported by the pivot so as to be in contact with or spaced from the signal line according to the operation of the electrostatic driving unit. The RF MEMS switch of claim 1, wherein the post has a cap formed at an upper end to limit the movement of the conductive switch pad. The RF MEMS switch of claim 1, wherein the pivot is integrally formed with one of the conductive switch pad, the ground, and the substrate. The RF MEMS switch of claim 1, wherein the conductive switch pad has a plurality of etching holes. The RF MEMS switch of claim 1, further comprising a conductive wire electrically connecting between the conductive switch pad and the ground. 2. The RF MEMS switch of claim 1, further comprising at least one balance driver configured to maintain the conductive switch pad at a predetermined interval without contacting the signal line. Preparing a silicon substrate; Forming a signal line, an electrostatic driving electrode, and a ground on the silicon substrate; Forming a conductive switch pad on the silicon substrate, the conductive switch pad having a pivot and an opening and capable of seesawing from side to side and up and down by the pivot; And And forming a first post on the silicon substrate, the first post being connected to the ground and inserted into the opening of the conductive switch pad to support the conductive switch pad to seesaw with respect to the pivot. Method of manufacturing an RF MEMS switch. The method of claim 7, wherein the forming of the signal line, the electrostatic driving electrode, and the ground comprises: Forming a first metal layer on the silicon substrate; And And patterning the first metal layer to form the signal line, the electrostatic driving electrode, and the ground. The method of claim 8, wherein the forming of the signal line, the electrostatic driving electrode, and the ground further comprises forming a balanced driving electrode. The method of claim 8, wherein the forming of the pivot and the conductive switch pad comprises: Forming a first sacrificial layer on the silicon substrate on which the signal line, the electrostatic driving electrode, and the ground are formed; Selectively etching the first sacrificial layer to form a pivot hole; Depositing a second metal layer on the first sacrificial layer on which the pivot hole is formed; And And patterning the second metal layer to form the conductive switch pad with the pivot. The method of claim 10, wherein the forming of the first post comprises: Forming a second sacrificial layer on the first sacrificial layer on which the conductive switch pad is formed; Selectively etching the first and second sacrificial layers to form post holes; Depositing a third metal layer on the second sacrificial layer on which the post hole is formed; Patterning the third metal layer to form the first post; And And removing the first and second sacrificial layers. The method of claim 11, The operation of forming the post hole further forms a wire / post hole for a conductive wire and a second post supporting the conductive wire; And the forming of the first post further comprises patterning the conductive wire and the second post supporting the conductive wire. The method of claim 8, wherein the forming of the pivot and the conductive switch pad comprises: Forming a first sacrificial layer on the silicon substrate on which the signal line, the electrostatic driving electrode, and the ground are formed; Selectively etching the first sacrificial layer to form a pivot hole; Depositing a second metal layer on the first sacrificial layer on which the pivot hole is formed; Patterning the second metal layer to form a pivot; Forming a second sacrificial layer on the pivoted first sacrificial layer; Depositing a third metal layer on the second sacrificial layer; And And forming the conductive switch pad by patterning the third metal layer. The method of claim 13, wherein forming the first post comprises: Forming a third sacrificial layer on the second sacrificial layer on which the conductive switch pad is formed; Selectively etching the first, second and third sacrificial layers to form post holes; Depositing a fourth metal layer on the third sacrificial layer on which the post hole is formed; Patterning the fourth metal layer to form the first post; And And removing said first, said second and said third sacrificial layer.

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