KR100997685B1 - Piezoelectric rf mems switch and fabrication method thereof - Google Patents

Abstract

The present invention relates to a piezoelectric RF MEMS switch and a method of manufacturing the same, and more particularly, a plurality of actuators operating in a piezoelectric force are provided around a contact pad, and each hinge connected between each driver and the contact pad is bent and pressed. By forming a typical RF MEMS switch, the contact pads can be displaced to switch the two RF signal lines even at low driving voltages, minimizing insertion loss by maintaining the flatness of the displaced contact pads. In addition, the present invention prevents the occurrence of noise and miniaturization is easy by placing the bridge-type driver in a direction perpendicular to the direction of the signal line.

Piezoelectric RF MEMS Switches, Bridge Type Drivers, Hinges, Contact Pads, Wafer Level Packaging

Description

Piezoelectric RF MMS switch and its manufacturing method {PIEZOELECTRIC RF MEMS SWITCH AND FABRICATION METHOD THEREOF}

The present invention relates to a RF micro electro mechanical system (RF MEMS) switch and a method of manufacturing the same, which are necessary for next generation intelligent radio frequency (RF) communication systems, radars, satellites, and measuring devices. By providing a plurality of contact pads around the contact pads and bending each hinge connected between each driver and the contact pads, even when a low driving voltage is applied, each hinge connected to each of the plurality of drivers and the plurality of drivers operates to operate the contact pads. The present invention relates to a piezoelectric RF MEMS switch that performs switching by connecting or shorting two RF signal lines that are disconnected from each other because is displaced.

Recently, with the development of information and communication technology, research for miniaturization, light weight, and high performance of devices has been actively conducted. In particular, the RF switch is a component for signal control and variable device implementation of information and communication devices, and is a key component having a wide range of applications and having a very important influence on device miniaturization and performance.

Current semiconductor switches such as MOSFETs and PIN diodes have poor frequency response and high power consumption, such as high insertion loss, low isolation, and nonlinearity. In comparison, RF MEMS switches have excellent frequency response and require low power consumption. Among them, the RF MEMS switch using electromagnetic force or thermal drive has high power consumption because the switching speed is slow and a lot of current is required to drive. On the other hand, the RF MEMS switch using the constant power has a fast switching speed and low power consumption, but it is not easy to apply to a portable mobile communication terminal requiring a high applied voltage of 30V or more when driving. Therefore, many RF MEMS switches using low piezoelectric power having a low driving voltage (for example, lower than 5V), low power consumption, and fast switching speed have been developed.

1 shows an example of a conventional piezoelectric RF MEMS switch. As shown in FIG. 1, a conventional piezoelectric RF MEMS switch includes a driver 10 that operates with piezoelectric power, a contact pad 20 that contacts two RF signal lines that are separated from each other, and the driver 10. It consists of a hinge (30) connected between the contact pads (20).

The hinge 30 is formed in a straight line.

When a driving voltage is applied, the driver 10 is mechanically operated by the piezoelectric force and the contact pad 20 is displaced through the hinge 30 at the end of the driver 10 due to the operation. By this displacement, the contact pads 20 operate as switches by connecting or shorting two RF signal lines which are separated from each other and disconnected.

However, since the conventional piezoelectric RF MEMS switch shown in FIG. 1 drives the contact pads with one driver, the pressure of the contact pads contacting the two RF signal lines is not constant, resulting in large insertion loss, and the contact pads are easily worn. There is a problem.

2 shows another example of a conventional piezoelectric RF MEMS switch. The conventional RF MEMS switch shown in FIG. 2 includes four drivers 10 that operate with piezoelectric force, and one contact pad 20 that contacts two RF signal lines that are separated from each other and is disconnected from each other. Four hinges 30 are provided between the 10 and the contact pads 20.

Each of the hinges 30 is formed in a straight line.

Since the conventional piezoelectric RF MEMS switch shown in FIG. 2 drives the contact pads with four drivers, the contact pads can be moved in parallel, so the insertion loss is smaller than that of the conventional RF MEMS switch shown in FIG. . However, in the conventional piezoelectric RF MEMS switch shown in FIG. 2, since the hinges are linearly connected to the contact pads, the bending degree of the hinge, that is, the displacement is not large, and thus the shock is not absorbed by the hinge when the overvoltage is applied. It is not likely to be transmitted to a driver composed of a piezoelectric layer. In addition, the conventional piezoelectric RF MEMS switch illustrated in FIG. 2 has a disadvantage in that miniaturization is not easy because the entire size of the switch is fixed by the size of the driver.

The present invention has been proposed in order to solve the problems of the prior art as described above, and an object of the present invention is to provide a plurality of actuators operating in a piezoelectric force around a contact pad, and each hinge connected between each driver and the contact pad. By bending and forming, it facilitates displacement even at low voltages, switching two RF signal lines, absorbing the shock from the hinge when overvoltage is applied, and minimizing the stress applied to the actuator composed of piezoelectric layers. The present invention provides a piezoelectric RF MEMS switch that maintains flatness to minimize insertion loss and is easily miniaturized, and a method of manufacturing the same.

In order to achieve the above object, a piezoelectric RF MEMS switch according to an embodiment of the present invention includes an upper substrate; Two signal terminals spaced apart at predetermined intervals from a lower end portion of the upper substrate; A lower substrate; A support of a cantilever structure which is formed to float on an upper portion of the lower substrate; A plurality of drivers formed on the support to drive with piezoelectric force; A contact pad contacting and detaching two signal terminals formed at a lower end of the upper substrate to switch signals; A hinge for extending and bending a portion of the support at one end of each of the plurality of drivers to connect the driver and the contact pad; A mold which maintains a gap between the upper substrate and the lower substrate; And a bonding layer bonding the upper substrate and the lower substrate.

In order to achieve the above object, a method of manufacturing a piezoelectric RF MEMS switch according to another embodiment of the present invention includes the steps of stacking silicon oxide, silicon nitride, and silicon oxide on top of a lower substrate; Depositing a lower electrode, a piezoelectric layer, and an upper electrode on an upper end of the stacked silicon oxide to form a plurality of bridge-type drivers through dry etching; Etching the exposed silicon oxide and silicon nitride after the formation of the plurality of drivers to form a support along the outer shape of the plurality of drivers and a hinge bent to a predetermined width and length to connect the plurality of drivers to each other; Forming a contact pad having a predetermined size at an upper end of a central portion of the hinge; And dry etching the exposed portion of the lower substrate to space the support, the hinge and the contact pad from the lower substrate.

In order to achieve the above object, a piezoelectric RF MEMS single-pole / multi-throw (SPMT) switch according to another embodiment of the present invention includes a plurality of piezoelectric RF MEMS switches according to the present invention connected radially. It is characterized by having one input port and a plurality of output ports.

The present invention forms a switch by providing a plurality of drivers such as two or four such that a piezoelectric actuator is formed in the form of a bridge around the contact pad, thereby always moving the contact pads in parallel to the RF signal line. The contact stress caused by the contact between the contact pad and the contact pad can be minimized to minimize the wear of the contact pad, and the contact force can be kept constant, minimizing the resistance generated to minimize the insertion loss. It is easy to paint.

According to the present invention, a plurality of actuators are provided around the contact pads, and each hinge connected between the actuators and the contact pads is bent to form a contact pad, so that the contact pads are easily displaced, thereby maximizing characteristics. In addition, even when an overvoltage is applied, the bent hinge absorbs the stress to minimize the stress applied to the piezoelectric driver and maintain a constant contact force between the contact pad and the signal line.

The present invention has the effect that the driver is formed in the form of a bridge to maximize the space efficiency in the array.

Since the present invention operates by providing a plurality of drivers, such as two or four, even if an operation abnormality occurs in at least one driver during a process or due to an unreasonable switching operation, the switch function is activated by at least one other driver. There is an effect that can be performed.

In the present invention, when the support for supporting the driver is formed on the lower substrate, silicon nitride and silicon oxide are further formed on the upper and lower portions of the silicon nitride to prevent corrosion of the silicon nitride when the cavity is formed in the center of the lower substrate. It can work.

The present invention forms a through hole in the upper substrate by wet etching and deposits a metal thin film on the upper substrate and the surface of the through hole by using a thin film deposition technique such as a sputter, a signal line, a driver electrode line and a ground line formed under the upper substrate, and an upper substrate. Since the signal line, the driver electrode line and the ground line formed in the connection are formed, the time required and the cost are reduced compared to the process of forming the through hole by using the RIE technology and plating the through hole.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a perspective view of a piezoelectric RF MEMS switch according to an embodiment of the present invention. As shown in FIG. 3, the piezoelectric RF MEMS switch according to an embodiment of the present invention includes an upper substrate (not shown in FIG. 3) and two formed at predetermined intervals at a lower end of the upper substrate. The signal terminal 210, the lower substrate 100, the support 110 having a cantilever structure formed by floating on an upper end portion of the lower substrate 100, and formed on the support 110 to drive with piezoelectric force. Two or four drivers 120, contact pads 130 contacting and detaching two signal terminals formed at the lower end of the upper substrate to switch signals, and one end of each of the plurality of drivers 120. A portion of the support 110 is extended and bent to the hinge (110a) connecting each of the driver 120 and the contact pad 130, and to maintain the gap between the upper substrate and the lower substrate A mold (not shown in FIG. 3), and the phase A bonding layer for bonding the substrate and the lower substrate 100 is formed (FIG. 3, not shown).

The upper substrate serves as a supporting substrate for the two signal terminals, and the upper substrate and the lower substrate 100 are bonded to each other while maintaining a predetermined interval so that the RF MEMS switch is packaged in a wafer unit. .

A through hole is formed in the upper substrate, a through hole connecting line (not shown in FIG. 3) is formed along the through hole, and both signal terminals are connected to the upper substrate through the through hole connecting line. Electrically connected to an external signal line formed on the upper end of the electrode and the electrode for driving each of the plurality of drivers is also electrically connected to the other external signal line formed on the upper end of the upper substrate through the through-hole connecting line.

The support 110 is formed of an insulating film having a low stress value.

The plurality of drivers 120 are formed in a bridge shape. In addition, the number of drivers 120 may be two or four.

Each of the plurality of drivers 120 is formed of a lower electrode, a piezoelectric layer, and an upper electrode (not shown in FIG. 3). The piezoelectric layer is made of PZT (Pb (Zr, Ti) O ₃ ) and has a ratio of Zr and Ti of 52:48 (morphotrop phase boundry (MPB)).

Two or four drivers 120 formed in a bridge shape are disposed in a direction perpendicular to the length direction of the two signal terminals 210 formed at the lower end of the upper substrate, and the arrangement is two signal terminals 210. Minimize noise generated in the

The hinge 110a may be bent in various shapes.

4A is a plan view of a piezoelectric RF MEMS switch according to a first embodiment of the present invention. As shown in FIG. 4A, in the piezoelectric RF MEMS switch according to the first embodiment of the present invention, two drivers 120 are provided in a bridge shape, and a contact pad is provided between two drivers 120 in a bridge shape. 130 is provided and the hinge (110a) is connected between each driver 120 and the contact pad 130, respectively.

Since a support (110 in FIG. 3) is formed at the lower ends of the two drivers 120, when a driving voltage is applied to each driver 120, each driver 120 is opposite to the support (110 in FIG. 3). It will cause displacement in the artificial direction.

One end of each driver 120 is fixed to the lower substrate, and the other end is connected to the contact pad 130 through the hinge 110a.

Each hinge 110a is formed to be bent in a "c" shape with a predetermined width and length, one end of which is connected to the side of one end of the driver 120 and the other end of which is connected to the side of the contact pad 130.

The operation of the piezoelectric RF MEMS switch according to the first embodiment of the present invention configured as described above will be described.

When a constant driving voltage is applied to each driver 120 including the upper electrode, the lower electrode, and the piezoelectric layer, each driver 120 is mechanically operated by polarization, and the hinge 120 is terminated due to the operation. A displacement difference occurs in the contact pads 130 connected through 110a). Due to such a displacement difference, the contact pad 130 contacts and detaches two signal terminals 210 of FIG. 3 disconnected from each other, thereby connecting or shorting the two signal terminals 210 of FIG. 3 to switch the RF signal. Done. At this time, since the two drivers 120 are connected to both sides of the contact pad 130 through the hinge 110a, the contact pad 130 is moved in parallel to contact the two signal terminals.

4B to 4D are plan views of piezoelectric RF MEMS switches according to the second, third, and fourth embodiments of the present invention, respectively. As shown in FIG. 4B, in the piezoelectric RF MEMS switch according to the second embodiment of the present invention, four drivers 120 are provided in a bridge shape, and contact pads are provided between the four drivers 120 in a bridge shape. 130 is provided and the hinge 110a is connected between each driver 120 and the contact pad 130, respectively.

Since a support (110 in FIG. 3) is formed at the lower ends of the four drivers 120, when a driving voltage is applied to each driver 120, each driver 120 is opposite to the support (110 in FIG. 3). It will cause displacement in the artificial direction.

Each hinge 110a is bent in a predetermined width and length in a shape of “a” or “ㅋ”, and one end is connected to the center of the end of each driver 120 and the other end is connected to the side of the contact pad 130. do.

Since the piezoelectric RF MEMS switch according to the present invention moves the contact pads at all times while keeping the contact pads in parallel by two or four drivers, the contact stress caused by the contact between the two signal terminals and the contact pads is caused. By minimizing the wear of the contact pad to minimize the contact force (contact force) can be kept constant, thereby minimizing the insertion resistance can be minimized. In addition, since the piezoelectric RF MEMS switch according to the present invention operates as two or four drivers, even if an abnormality occurs in one or two drivers during the process or due to excessive switching operation, the piezoelectric RF MEMS switch is operated as a switch by the remaining normal drivers. Function can be performed, and the actuator is connected in the form of a bridge to maximize space efficiency in the array.

In addition, in the piezoelectric RF MEMS switch according to the present invention, a plurality of bridge-type drivers and contact pads are formed in a direction perpendicular to the length direction of two signal terminals formed on the upper substrate, thereby minimizing noise generation.

FIG. 5A is a graph showing the degree of displacement of a piezoelectric RF MEMS switch (for A) and a piezoelectric RF MEMS switch (for B) according to the present invention including two drivers in the form of a bridge. to be. As shown in FIG. 5A, it can be seen that the piezoelectric RF MEMS switch according to the present invention having two drivers in the form of a bridge is displaced while maintaining smoothness more stably.

FIG. 5A is a graph showing the degree of displacement of a piezoelectric RF MEMS switch (for A) and a piezoelectric RF MEMS switch (for B) according to the present invention in which two drivers are formed in a bridge form. As shown in Figure 5a, it can be seen that the flatness (flatness) of the contact pad of the piezoelectric RF MEMS switch according to the present invention is superior to the conventional piezoelectric RF MEMS switch.

5B is a displacement of the piezoelectric RF MEMS switch (in the case of D) according to the present invention in which four drivers are formed in the form of a bridge and the conventional piezoelectric RF MEMS switch (in the case of C) in which the four drivers are formed in the form of a windmill. It is a graph showing the degree.

6A illustrates a state in which noise is formed at two signal terminals by the conventional piezoelectric RF MEMS switch of FIG. 2 in which four drivers are formed in a windmill shape. Since four drivers 120 formed in the shape of a pinwheel are provided close to two signal terminals 210, the contact pad 130 contacts the two signal terminals 210 to provide an RF signal to the signal terminal 210. In this case, it can be seen that interference occurs in the RF signal due to a coupling phenomenon between the signal terminal 210 and the upper electrode of the driver 120.

6b to 6c show that since two or four drivers in the form of bridges are formed in a direction perpendicular to the length direction of the signal terminal, there is no interference effect because no coupling phenomenon occurs between the upper electrode and the signal terminal of the driver. Indicates.

7 is a cross-sectional view of a piezoelectric RF MEMS switch manufactured by a method of manufacturing a piezoelectric RF MEMS switch according to a first embodiment of the present invention. A method of manufacturing a piezoelectric RF MEMS switch according to a first embodiment of the present invention will be described with reference to FIG. 7.

First, the manufacturing method of the lower substrate of the piezoelectric RF MEMS switch according to the first embodiment of the present invention will be described.

First, the silicon oxide 111, the silicon nitride 112, and the silicon oxide 113 are stacked on the upper end of the lower substrate 100 in order.

After depositing the lower electrode 121, the piezoelectric layer 122, and the upper electrode 123 on the stacked upper silicon oxide 113, a plurality of bridge-type drivers 120 are formed through dry etching.

The silicon oxide 113 and the silicon nitride 112 exposed after the formation of the plurality of drivers 120 are etched to be bent to a support 110 along the outer shape of the plurality of drivers 120, and to have a predetermined width and length. A hinge 110a connecting the plurality of drivers 120 to each other is formed.

A contact pad 130 having a predetermined size is formed at an upper end of a central portion of the hinge 110a.

When the upper substrate is bonded to the lower substrate, the plurality of drivers may include a dam 140 that prevents a short circuit between the upper electrode 123 and the lower electrode 121 of each of the plurality of drivers 120 due to diffusion of the bonding layer. On 120.

In order to space a portion of the support 110, the hinge 110a, and the contact pad 130 from the lower substrate 100, the exposed portion of the lower substrate 100 is dry-etched to form a cavity. .

The lower substrate 100 is dry-etched with xenon to form a cavity. In the case of dry etching to form the cavity, the support is further formed by adding silicon oxides 111 and 113 to protect the silicon nitride 112 to prevent corrosion of the silicon nitride 112 which will serve as a support. . Accordingly, the support 110 is formed in a structure in which the silicon oxide 111, the silicon nitride 112, and the silicon oxide 113 are sequentially stacked. The support 110 and the hinge 110a have the same material and layer structure, but the part supporting the driver 120 is the support 110 and is bent to connect the driver 120 and the contact pad 130. The portion to be hinged (110a).

Through this process, the lower substrate 100 of the piezoelectric RF MEMS switch according to the first embodiment of the present invention is manufactured.

Next, a method of manufacturing the upper substrate of the piezoelectric RF MEMS switch and the method of bonding the upper substrate and the lower substrate to the first embodiment of the present invention will be described.

First, through-holes are formed in the upper substrate 200, the through-holes are filled with metal to form the through-hole connecting lines 230, and are polished by chemical mechanical polishing (CMP), and the lower portion of the polished through-hole connecting lines 230 is formed. Two signal terminals 210 disposed in a longitudinal direction and a vertical direction of the plurality of drivers 120 formed on the lower substrate 100, and an upper part connected to the upper electrodes 123 of the plurality of drivers 120, respectively. An electrode line 222 and a lower electrode line 221 and a ground line 220 which are connected to the lower electrode 121 of each of the plurality of drivers 120 are formed.

In order to maintain a gap between the upper substrate 200 and the lower substrate 100, a bonding layer 242 is formed at the lower end of the mold 241 and the mold 241 to form a spacer 240. Then, the upper substrate 200 and the lower substrate 100 are bonded to each other.

The upper end of the bonded upper substrate 200 is polished by chemical mechanical polishing (CMP) to expose the through holes.

An external signal line 211 connected to the two signal terminals 210, an external upper electrode line connected to the upper electrode line 222, and an external lower electrode line connected to the lower electrode line 221. 223 and a ground line 221 are formed.

In this manner, the piezoelectric RF MEMS switch according to the first embodiment of the present invention is formed.

8 is a cross-sectional view of a piezoelectric RF MEMS switch manufactured by a method of manufacturing a piezoelectric RF MEMS switch according to a second embodiment of the present invention. A method of manufacturing a piezoelectric RF MEMS switch according to a second embodiment of the present invention will be described with reference to FIG. 8.

Since the same as the manufacturing method of the lower substrate of the piezoelectric RF MEMS switch according to the first embodiment of the present invention described with reference to Figure 7, the manufacturing of the lower substrate of the piezoelectric RF MEMS switch according to the second embodiment of the present invention A description of the method will be omitted, and a method of manufacturing an upper substrate and a method of bonding and packaging the upper substrate and the lower substrate will be described.

First, silicon oxide 250 is formed at a lower end of the upper substrate 200. The silicon oxide 250 may include two signal terminals 210, a driver upper electrode line 222, a lower electrode line 221 formed on a lower end of the upper substrate 200 when a through hole is formed through wet etching. To protect the ground line 220.

Two signal terminals 210 disposed in the longitudinal direction and a vertical direction of the plurality of drivers 120 formed on the lower substrate 100 on the formed silicon oxide 250, and upper electrodes of the plurality of drivers 120, respectively. A driver upper electrode line 222 connected to 123, a driver lower electrode line 221 connected to the lower electrode 121 of each of the plurality of drivers 120, and a ground line are formed.

In order to maintain a gap between the upper substrate 200 and the lower substrate 100, a bonding layer 242 is formed at the lower end of the mold 241 and the mold 241 to form a spacer 240. Then, the upper substrate 200 and the lower substrate 100 are bonded to each other.

The upper end portion of the bonded upper substrate 200 is polished by chemical mechanical polishing (CMP). Through-holes are formed in the upper substrate 200 through wet etching.

After depositing a metal thin film by the thin film deposition technique on the upper substrate 200, the through hole is formed, the external signal line 211 is connected to the two signal terminals 210, the driver is connected to the upper electrode line 222 An external upper electrode line 224 and an external lower electrode line 221 and a ground line 221 which are connected to the lower electrodes 121 of the plurality of drivers 120 are formed.

The through holes formed through the wet etching are not filled with metal, but the thin metal film is deposited using a thin film deposition technique such as a sputter to form through hole connecting lines. Therefore, the time required for forming the through-hole connecting line can be shortened and manufacturing cost can be reduced.

For reference, FIG. 3 is a three-dimensional perspective view of the portion A in FIG. 7 and a three-dimensional perspective view of the portion B in FIG. 8.

9 illustrates a structure of an RF MEMS single-pole / multi-throw (SPMT) switch in which a plurality of piezoelectric RF MEMS switches according to the present invention are arranged in a radial form.

In the RF MEMS single-pole / multi-throw (SPMT) switch according to the present invention, a plurality of piezoelectric RF MEMS switches 310-360 according to the present invention are formed in a radial form and connected to one input port (In). And a plurality of output ports OUT1-OUT6. Each of the plurality of piezoelectric RF MEMS switches 310-360 may include an input port In through which a signal is input and external upper electrode lines S11, S21, S31, S41, and a driving voltage for driving the plurality of drivers. S51.S61, external lower electrode lines S12, S22, S32, S42, S52, and S62 for grounding, and output ports OUT1-OUT6 for switching and outputting the input signal. The RF signal characteristics of the plurality of output ports OUT1-OUT6 remain the same.

A piezoelectric RF MEMS switch in which a driving voltage is applied to the external upper electrode line among the plurality of piezoelectric RF MEMS switches 310 to 360 operates to switch and output a signal input to the input port In.

For example, when the mobile communication terminal receives the DMB signal, when the driving voltage is applied to the external upper electrode line S11 of the first piezoelectric RF MEMS switch 310 in charge of the DMB signal switching, the first piezoelectric type The RF MEMS switch 310 operates to switch the DMB signal input to the input port In to output the output port OUT1.

As described above, since a plurality of drivers formed in the form of a bridge are disposed in a direction perpendicular to the length direction of the RF signal line, the plurality of piezoelectric RF MEMS switches according to the present invention are radially connected to the plurality of RF MEMS SPMTs (single-pole / multi- throw) The switch can be easily formed by miniaturization, and the space efficiency can be maximized. In addition, according to the form of connecting the piezoelectric RF MEMS switch according to the present invention it is also possible to form an RF MEMS multi-pole / multi-throw (MPMT) switch.

As described above, the RF MEMS switch according to the present invention has excellent frequency response characteristics and power consumption, and thus can be used for digitally controlled antennas, satellite systems, and various wireless communications. Application is also possible. In addition, the piezoelectric RF MEMS switch operated by the two or four drivers proposed in the present invention can improve the reliability and insertion loss, which is advantageous for application in the field.

Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. The disclosed embodiments are not intended to limit the invention but to illustrate the invention. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a view showing an example of a conventional piezoelectric RF MEMS switch.

2 is a view showing another example of a conventional piezoelectric RF MEMS switch.

3 is a perspective view of a piezoelectric RF MEMS switch according to an embodiment of the present invention.

4A is a plan view of a piezoelectric RF MEMS switch according to a first embodiment of the present invention;

4B is a plan view of a piezoelectric RF MEMS switch according to a second embodiment of the present invention;

4C is a plan view of a piezoelectric RF MEMS switch according to a third embodiment of the present invention;

4D is a plan view of a piezoelectric RF MEMS switch according to a fourth embodiment of the present invention;

FIG. 5A is a graph showing the degree of displacement of a piezoelectric RF MEMS switch (for A) and a piezoelectric RF MEMS switch (for B) according to the present invention including two drivers in the form of a bridge. .

5B is a displacement of the piezoelectric RF MEMS switch (in the case of D) according to the present invention in which four drivers are formed in the form of a bridge and the conventional piezoelectric RF MEMS switch (in the case of C) in which the four drivers are formed in the form of a windmill. Graph showing degree.

FIG. 6A illustrates a noise generation state of the conventional piezoelectric RF MEMS switch of FIG. 2 in which four drivers are formed in the form of a windmill; FIG.

Figure 6b is a view showing a noise cancellation state by the piezoelectric RF MEMS switch of the present invention formed with two drivers in the form of a bridge.

Figure 6c is a diagram showing a noise cancellation state by the piezoelectric RF MEMS switch of the present invention in which four drivers in the form of a bridge are formed in the form of a bridge.

7 is a cross-sectional view of a piezoelectric RF MEMS switch manufactured by the method of manufacturing a piezoelectric RF MEMS switch according to the first embodiment of the present invention.

8 is a cross-sectional view of a piezoelectric RF MEMS switch manufactured by the method of manufacturing a piezoelectric RF MEMS switch according to a second embodiment of the present invention.

9 is a diagram illustrating an RF MEMS single-pole / multi throw (SPMT) switch formed by connecting a plurality of piezoelectric RF MEMS switches according to the present invention in a radial form.

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

100: lower substrate 110: support

110a: hinge 120: driver

130: contact pad 111,113: silicon oxide

112: silicon nitride 121: lower electrode

122: piezoelectric layer 123: upper electrode

140: dam 200: upper substrate

210: RF signal line 211: External signal line

220: RF ground wire 212: external ground wire

221: lower electrode line 222: upper electrode line

223: external lower electrode line 224: external upper electrode line

230: through hole connecting line 240: spacer

241 mold 242 bonding layer

250: silicon oxide

310-360: first to sixth piezoelectric RF MEMS switches

S11-S61: external upper electrode line S12-S62: external lower electrode line

OUT1-OUT6: Output Port In: Input Port

Claims (11)

An upper substrate; Two signal terminals spaced apart at predetermined intervals from a lower end portion of the upper substrate; A lower substrate; A support of a cantilever structure which is formed to float on an upper portion of the lower substrate; A plurality of drivers formed on the support to drive with piezoelectric force; A contact pad contacting and detaching two signal terminals formed at a lower end of the upper substrate to switch signals; A hinge for extending and bending a portion of the support at one end of each of the plurality of drivers to connect the driver and the contact pad; A mold which maintains a gap between the upper substrate and the lower substrate; And Piezoelectric RF MEMS switch formed of a bonding layer for bonding the upper substrate and the lower substrate. The piezoelectric RF MEMS switch of claim 1, wherein the plurality of drivers are formed in a bridge shape. The piezoelectric RF MEMS switch of claim 1, wherein the number of the plurality of drivers is two or four. The hinge according to claim 1 or 2, The piezoelectric RF MEMS switch is formed to be bent in a "c" shape with a predetermined width and length, one end is connected to the side of the end of each driver and the other end is connected to the side of the contact pad. The hinge according to claim 1 or 2, The piezoelectric RF MEMS switch is formed to be bent in a predetermined width and length in the form of "a", one end is connected to the center of the end of each driver and the other end is connected to the side of the contact pad. The hinge according to claim 1 or 2, A piezoelectric RF MEMS switch, characterized in that formed in a bent in the shape of a predetermined width and length, one end is connected to both sides of the end of each driver and the other end is connected to the side of the contact pad. The method according to claim 1, Through-holes are formed in the upper substrate by wet etching, and through-hole connection lines are formed by depositing a metal thin film on the surface of the through-holes, and one of the two signal terminals is connected to an upper end of the upper substrate through the through-hole connection lines. Piezoelectric RF MEMS switch characterized in that it is electrically connected to the formed external signal line. In the piezoelectric RF MEMS switch manufacturing method, Stacking silicon oxide, silicon nitride, and silicon oxide on top of the lower substrate in order; Depositing a lower electrode, a piezoelectric layer, and an upper electrode on an upper end of the silicon oxide stacked on the silicon nitride to form a plurality of bridge-type drivers through dry etching; Etching silicon oxide and silicon nitride exposed after the formation of the plurality of drivers to form a support along the outer shape of the plurality of drivers, and a hinge bent to a predetermined width and length to connect the plurality of drivers to each other; Forming a contact pad having a predetermined size at an upper end of a central portion of the hinge; And dry etching the exposed portion of the lower substrate so as to space the support, the hinge and the contact pad from the lower substrate. The method according to claim 8, Through-holes are formed in the upper substrate, the through-holes are filled with metal to form through-hole connecting lines, and polished by chemical mechanical polishing (CMP), and the longitudinal direction of the plurality of actuators formed on the lower substrate under the polished through-holes. Forming two signal terminals arranged in a vertical direction, an upper electrode line connected to an upper electrode of a driver, a lower electrode line and a ground line connected to a lower electrode of each of the plurality of drivers; Forming a mold to maintain a gap between the upper substrate and the lower substrate; Bonding the upper substrate and the lower substrate to each other; Polishing the upper end of the bonded upper substrate by chemical mechanical polishing (CMP) to expose the through hole; And forming an external signal line connected to the two signal terminals, an external upper electrode line connected to the upper electrode line, an external lower electrode line connected to the lower electrode line, and a ground line on the exposed through hole. Piezoelectric RF MEMS switch manufacturing method. The method according to claim 8, Forming silicon oxide on a lower end of the upper substrate; Two signal terminals disposed in the longitudinal direction and a vertical direction of the plurality of drivers formed on the lower substrate on the formed silicon oxide, an upper electrode line connected to the upper electrodes of the plurality of drivers, and a lower electrode of each of the plurality of drivers; Forming a lower electrode line and a ground line to be connected to each other; Forming a mold to maintain a gap between the upper substrate and the lower substrate; Bonding the upper substrate and the lower substrate to each other; Polishing the upper end of the bonded upper substrate by chemical mechanical polishing (CMP); Forming a through hole in the upper substrate through wet etching; After depositing a metal thin film on the upper end of the upper substrate with the through hole formed by a thin film deposition technique, an external signal line connected to the two signal terminals, an external upper electrode line connected to the upper electrode line, an outer lower portion connected to the lower electrode line Piezoelectric RF MEMS switch manufacturing method comprising the step of forming an electrode line and a ground line. Piezoelectric RF MEMS switch according to claim 1 is arranged in a plurality of radially provided with one input port and a plurality of output ports, Each of the plurality of piezoelectric RF MEMS switches may include an input port to which a signal is input, an external upper electrode line to which a driving voltage for driving the plurality of drivers is input, an external lower electrode line for grounding, and the input signal. RF MEMS single-pole / multi-throw (SPMT) switch characterized in that it has an output port for outputting.

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