CN108417453B - Radio frequency micro mechanical switch and manufacturing method thereof - Google Patents
Radio frequency micro mechanical switch and manufacturing method thereof Download PDFInfo
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- CN108417453B CN108417453B CN201810066726.3A CN201810066726A CN108417453B CN 108417453 B CN108417453 B CN 108417453B CN 201810066726 A CN201810066726 A CN 201810066726A CN 108417453 B CN108417453 B CN 108417453B
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- contact
- swing arm
- radio frequency
- mechanical switch
- cantilever beam
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H59/00—Electrostatic relays; Electro-adhesion relays
- H01H59/0009—Electrostatic relays; Electro-adhesion relays making use of micromechanics
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/10—Auxiliary devices for switching or interrupting
Abstract
The invention relates to the field of electronic devices, and discloses a radio frequency micro mechanical switch, which comprises: the base of horizontal setting to and set up signal line contact and the ground contact above the base, still include: the signal wire is arranged above the substrate and comprises a first contact part opposite to the signal wire contact and a second contact part opposite to the ground wire contact; the cantilever beam drives the first contact part to contact the signal line contact and drives the second contact part to be far away from the ground line contact so as to close the radio frequency micro mechanical switch; the cantilever beam drives the first contact part to be far away from the signal line contact and drives the second contact part to be in contact with the ground line contact, so that the radio frequency micro mechanical switch is switched off. The radio frequency micro mechanical switch provided by the embodiment of the invention can reduce the insertion loss and improve the isolation degree and the power processing capability of a high frequency band.
Description
Technical Field
The invention relates to the field of electronic devices, in particular to a radio frequency micro mechanical switch and a manufacturing method thereof.
Background
With the rapid development of microwave or radio frequency communication technology, there is an urgent need for microwave/radio frequency micro mechanical switches in order to improve the performance and integration level of subsystems and complete machines. Compared with the traditional microwave elements such as field effect transistors, ferrites or PIN diodes, the microwave/radio frequency micro mechanical switch has the advantages of high working frequency, low power consumption, low insertion loss, high isolation and the like. The actuating mechanism of the microwave/radio frequency micro-mechanical switch has two types: electrostatic interaction and electromagnetic interaction. At present, the more researched and more mature is the electrostatic driving metal contact type micro mechanical switch, and the switch structure mainly comprises three parts, namely a cantilever beam or a suspension membrane bridge, a driving electrode and a microwave signal wire.
The inventor finds that at least the following problems exist in the prior art: in the prior art, the electrostatic driving radio frequency micro mechanical switch has large insertion loss and poor isolation and power processing capability in a high frequency band, and further improvement of subsystem integration and application fields thereof are limited. Therefore, there is a need to provide a new structure of rf micro mechanical switch to solve the above problems.
Disclosure of Invention
The invention aims to provide a radio frequency micro mechanical switch, which reduces the insertion loss and improves the isolation and the power processing capability of the radio frequency micro mechanical switch.
In order to solve the above technical problem, an embodiment of the present invention provides a radio frequency micro mechanical switch, including: the base that sets up horizontally to and set up signal line contact and ground wire contact above the base, radio frequency micro-mechanical switch still includes: the signal wire comprises a first contact part and a second contact part, wherein the first contact part is arranged right opposite to the signal wire contact, and the second contact part is arranged right opposite to the ground wire contact; the cantilever beam drives the first contact part to contact the signal line contact and drives the second contact part to be far away from the ground line contact, so that the radio frequency micro mechanical switch is closed; the cantilever beam drives the first contact part to be far away from the signal line contact and drives the second contact part to be in contact with the ground line contact, so that the radio frequency micro-mechanical switch is switched off.
Compared with the prior art, when the switch is closed, the first contact part is in contact with the signal line contact to conduct the radio frequency micro mechanical switch, the second contact part is far away from the ground line contact, the distance between the second contact part and the ground line is larger, the insertion loss of the switch is reduced, and meanwhile, when the switch is opened, the first contact part is far away from the signal line contact, so that the coupling capacitance between the signal line and the signal line contact is reduced, the second contact part is in good contact with the ground line contact, coupling useless radio frequency signals are led into the ground line, and the good isolation degree and the power processing capacity of the radio frequency micro mechanical switch in a high frequency range are achieved.
In addition, the conducting wire further comprises a first swing arm and a second swing arm intersected with the first swing arm, the number of the signal wire contacts and the number of the first contact parts are two, and the two first contact points are located at two ends of the first swing arm and far away from the joint of the first swing arm and the second swing arm.
In addition, the first swing arm and the second swing arm are perpendicular to each other. Due to the arrangement, the arrangement of other parts is more convenient, and the reasonable arrangement layout of the internal structure of the radio frequency micro mechanical switch is facilitated.
In addition, the ground wire contact and the second contact parts are two, and the two second contact parts are located at two ends of the second swing arm and far away from the joint of the second swing arm and the first swing arm.
In addition, the ground wire contact and the second contact part are both one, and the second contact part is located at one end of the second swing arm and is far away from the joint of the second swing arm and the first swing arm.
In addition, an insulating medium layer is arranged on the substrate, the number of the cantilever beams is multiple, the cantilever beams correspond to the first contact parts and the second contact parts one to one, one ends of the cantilever beams are fixed on the insulating medium layer, the other ends of the cantilever beams are free ends, and the free ends drive the corresponding first contact parts or the corresponding second contact parts to swing in the horizontal direction. Because the cantilever beam swings in the horizontal direction and does not displace in the vertical direction, the space in the vertical direction can be saved, the vertical thickness of the radio frequency micro mechanical switch is reduced, and the miniaturization design of the radio frequency micro mechanical switch is facilitated.
In addition, the conducting wire is arranged on the cantilever beam, the first contact part and the second contact part are respectively arranged on the side surface of the free end of the cantilever beam corresponding to the first contact part and the second contact part, and the signal wire contact and the ground wire contact are respectively arranged at the positions close to the free end of the cantilever beam. So set up, when the deformation that the cantilever beam takes place, first contact site and second contact site have as big displacement distance as possible, under the condition that needs satisfy predetermined displacement distance, the required drive voltage of cantilever beam is littleer in this kind of design.
In addition, the cantilever beam driving device further comprises piezoelectric driving pieces which are arranged on the cantilever beams to drive the corresponding cantilever beams to move in the horizontal direction, and the piezoelectric driving pieces and the corresponding first contact parts or the corresponding second contact parts on the cantilever beams are respectively positioned on two opposite side surfaces of the cantilever beams in the horizontal direction.
Drawings
Fig. 1 is a schematic perspective view of a radio frequency micro-mechanical switch according to a first embodiment of the present invention;
FIG. 2 is a cross-sectional view taken along A-A in FIG. 1;
FIG. 3 is an enlarged view of a portion of FIG. 2 at B;
fig. 4 is a flow chart of a method of fabricating a radio frequency micro-mechanical switch in a second embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present invention in its various embodiments. However, the technical solutions claimed in the claims of the present invention can be implemented without these technical details and with various changes and modifications based on the following embodiments.
A first embodiment of the present invention relates to a radio frequency micro-mechanical switch 100, as shown in fig. 1, 2, and 3, including a substrate 11, a signal line contact 12, a ground line contact 13, a via line 14, and a cantilever beam 15. The substrate 11 is horizontally disposed, the signal line contact 12, the ground line contact 13, and the via line 14 are disposed above the substrate 11, and the cantilever beam 15 drives the via line 14 to move in the horizontal direction. The via 14 includes a first contact portion 141 provided facing the signal line contact 12 and a second contact portion 142 provided facing the ground line contact 13. The cantilever beam 15 drives the first contact portion 141 to contact the signal line contact 12 and drives the second contact portion 142 away from the ground line contact 13, so that the radio frequency micro-mechanical switch 100 is closed; the cantilever beam 15 drives the first contact portion 141 away from the signal line contact 12 and drives the second contact portion 142 into contact with the ground line contact 13 to open the radio frequency micro-mechanical switch 100.
Compared with the prior art, the first contact part 141 and the signal line contact 12 are well contacted, the second contact part 142 and the ground line contact 13 are far away, and the second contact part 142 and the ground line contact 13 are far away when the switch is closedGround wire 18Further apart from each otherThe insertion loss of the switch is reduced, and at the same time, when the switch is turned off, the first contact portion 141 is far away from the signal line contact 12, so that the coupling capacitance between the conducting line 14 and the signal line contact 12 is reduced, and the second contact portion 142 is in good contact with the ground line contact 13, so that the coupled useless radio frequency signals are guided into the ground line 18, and the good isolation and the power processing capability of the radio frequency micro mechanical switch 100 in a high frequency range are realized.
It should be noted that, in practical applications, the conducting line 14 includes a plurality of swing arms having contact portions, and the contact portions of the swing arms are respectively defined as the aforementioned first contact portion 141 and the second contact portion 142 so as to respectively contact or be away from the signal line contact 12 and the ground line contact 13 in the operating state where the radio frequency micro mechanical switch 100 is closed or opened. Specifically, in the present embodiment, the conducting wire 14 further includes a first swing arm 143 and a second swing arm 144 intersecting with the first swing arm 143, the number of the signal wire contacts 12 and the first contact portion 141 is two, and the two first contact points are located at two ends of the first swing arm 143 and are far from a joint of the first swing arm 143 and the second swing arm 144. The number of the ground contacts 13 and the number of the second contact portions 142 may be two, and the two second contact portions 142 are located at two ends of the second swing arm 144 and are far away from the junction of the second swing arm 144 and the first swing arm 143, so as to be conducted with the ground to introduce the coupled unwanted rf signals into the ground, thereby achieving better isolation and power processing capability in the high frequency band. It will be appreciated that the above effect can also be achieved when the ground contact 13 and the second contact portion 142 are both one, and in this case, the second contact portion 142 is located at one end of the second swing arm 144 and away from the junction of the second swing arm 144 and the first swing arm 143.
In addition, the relative positions of the first swing arm 143 and the second swing arm 144 are not particularly limited, and they may intersect at any angle. Preferably, in the present embodiment, the first swing arm 143 and the second swing arm 144 are perpendicular to each other. The arrangement is convenient for arrangement of other components, and is beneficial to rationalizing arrangement and layout of the internal structure of the radio frequency micro mechanical switch 100.
The cantilever beam 15 in this embodiment functions to support the first swing arm 143 and the second swing arm 144 and to move the first contact portion 141 and the second contact portion 142. Specifically, an insulating medium layer 16 is disposed on the substrate 11, a plurality of cantilever beams 15 are provided, the cantilever beams 15 correspond to the first contact portions 141 and the second contact portions 142 one to one, one end of each cantilever beam 15 is fixed on the insulating medium layer 16, the other end of each cantilever beam 15 is a free end 151, and the free end 151 drives the corresponding first contact portion 141 or the corresponding second contact portion 142 to swing in the horizontal direction. Because the cantilever beam 15 swings in the horizontal direction and has no displacement in the vertical direction, the space in the vertical direction can be saved, the vertical thickness of the radio frequency micro mechanical switch 100 is reduced, and the miniaturization design of the radio frequency micro mechanical switch 100 is facilitated.
It should be noted that, when the conducting wire 14 is disposed on the cantilever beam 15, the first contact portion 141 and the second contact portion 142 are disposed on the side surfaces of the free end 151 of the cantilever beam 15 corresponding thereto, and the signal wire contact 12 and the ground wire contact 13 are disposed near the free end 151 of the cantilever beam 15. With this arrangement, the first contact portion 141 and the second contact portion 142 have the largest possible displacement distance when the cantilever beam 15 is deformed, and the driving voltage required by the cantilever beam 15 in the design scheme is smaller in the case that the predetermined displacement distance needs to be satisfied. Meanwhile, when the first contact portion 141 or the second contact portion 142 is in better contact with the corresponding contact or is disconnected, the distance is further increased, and the isolation and the power processing capability of the radio frequency micro mechanical switch 100 in a high frequency band are further improved.
In order to provide the cantilever beams 15 with the driving force for swinging the first swing arm 143 and the second swing arm 144, the rf micro-mechanical switch 100 may further include a piezoelectric driving plate 17 disposed on each of the cantilever beams 15 to drive the corresponding cantilever beam 15 to move in the horizontal direction. In this embodiment, each of the piezoelectric driving pieces 17 and the first contact portion 141 or the second contact portion 142 of the cantilever 15 are respectively located on two side surfaces of the cantilever 15 opposite to each other in the horizontal direction. Of course, it is understood that each of the piezoelectric driving pieces 17 and the corresponding first contact portion 141 or the second contact portion 142 of the cantilever 15 may be located on the same side.
It is worth mentioning that the materials of the signal line contact 12, the ground line contact 13, and the signal line include, but are not limited to, gold (Au), copper (Cu), aluminum (Al), nickel (Ni), tungsten (W), etc.; the material of the substrate 11 includes, but is not limited to, high-resistivity silicon, ceramic, polymer, glass, or the like; the material of the insulating dielectric layer 16 includes but is not limited to silicon dioxide, polysilicon, silicon nitride, or polymer; piezoelectric layer materials of the piezoelectric sheet include, but are not limited to, aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), or the like; materials of cantilever beam 15 include, but are not limited to, silicon dioxide, single crystal silicon, silicon nitride, or polymers, among others.
A second embodiment of the present invention provides a method for manufacturing a radio frequency micro mechanical switch 100, as shown in fig. 4, including:
s10: and depositing an insulating medium layer 16 on the surface of the silicon wafer by a low-pressure chemical vapor deposition method.
Specifically, in step S10, a silicon soi (silicon on insulator) substrate on an insulating substrate is cleaned with an acidic cleaning solution and an alkaline cleaning solution, respectively, and then the substrate is cleaned with deionized water; then using a low pressure chemical vapor deposition device to deposit the thickness of the front surface of the SOI substrate
The silicon dioxide film layer is used as a mask layer; and coating photoresist on the front side of the substrate, carrying out photoetching exposure, forming a photoetching pattern at a position where a groove needs to be etched, putting the developed and dried silicon wafer into silicon dioxide corrosive liquid, and carrying out wet etching to obtain a needed mask window.
S11: the cantilever beam 15 structure is formed by a dry deep silicon etching method.
Specifically, in step S11, the SOI substrate is placed in a dry deep silicon etching apparatus for etching
Deep vertical sidewall recesses.
S12: and soaking by adopting hydrofluoric acid solution to release the cantilever beam 15 structure.
Specifically, in step S12, after the etching is completed, the SOI substrate is placed in a low-concentration hydrofluoric acid solution to remove the silicon dioxide layer under the cantilever beam 15, thereby completing the releasing of the structure of the switch cantilever beam 15.
S13: and depositing a lower electrode metal layer, a piezoelectric film and an upper electrode metal layer by a vacuum evaporation method or a magnetron sputtering method, and forming a lower electrode and an upper electrode by a photoetching method.
Specifically, in step S13, a photoresist is first applied as a bonding material to fix the SOI substrate 11 and the mask layer (Shadow mask). Under the cover of the mask layer, the insulating medium layer 16 is sequentially prepared by using a vacuum evaporation device or a sputtering device
Titanium (Ti) and platinum (Pt) layers with the thickness to form a Ti/Pt lower electrode composite layer; and after the completion, putting the substrate into a heated acetone solution to dissolve the photoresist, and then washing the substrate clean by using deionized water. Prepared by the same procedure on the surface of the lower electrode using a sputtering apparatus
The thickness of the PZT piezoelectric film layer is measured, and then annealing polarization is carried out under the condition of 700 ℃. Then preparing on the piezoelectric film by utilizing vacuum evaporation or magnetron sputtering equipment again
A thick Pt layer to form an upper electrode metal film layer.
S14: the microwave metal transmission line is formed by a vacuum evaporation method or a magnetron sputtering method.
Specifically, in step S14, a photoresist is first applied as a bonding material to fix the SOI substrate 11 and the mask layer (Shadow mask). And under the shielding of the mask layer, sequentially depositing Ti layers with the thickness of 0.01 mu m and Au layers with the thickness of 2 mu m on the surface and the side walls of the substrate by utilizing vacuum evaporation equipment or sputtering equipment to form the Ti/Au composite layer microwave transmission line.
S15: soaking and stripping by using an acetone solution, and cleaning by using absolute ethyl alcohol and deionized water.
Specifically, in step S15, the substrate is placed in a heated acetone solution to dissolve the photoresist, and then the substrate is rinsed with absolute ethanol and deionized water. And putting the cleaned substrate into an oven for drying.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.
Claims (7)
1. A radio frequency micro-mechanical switch comprising a horizontally disposed substrate, and a signal line contact and a ground line contact disposed above the substrate, characterized in that the radio frequency micro-mechanical switch further comprises: the conducting wire comprises a first contact part and a second contact part, wherein the first contact part is arranged right opposite to the signal wire contact, and the second contact part is arranged right opposite to the ground wire contact;
the cantilever beam drives the first contact part to contact the signal line contact and drives the second contact part to be far away from the ground line contact, so that the radio frequency micro mechanical switch is closed;
the cantilever beam drives the first contact part to be far away from the signal line contact and drives the second contact part to be in contact with the ground line contact, so that the radio frequency micro mechanical switch is switched off; the conducting wire further comprises a first swing arm and a second swing arm intersected with the first swing arm, the number of the signal wire contacts is two, and the first contact parts are located at two ends of the first swing arm and far away from the joint of the first swing arm and the second swing arm.
2. The radio frequency micro-machined switch according to claim 1, wherein the first swing arm and the second swing arm are perpendicular to each other.
3. The rf micro-machined switch of claim 2, wherein there are two ground contacts and two second contacts, and the two second contacts are located at two ends of the second swing arm and away from a junction of the second swing arm and the first swing arm.
4. The rf micro-machined switch of claim 2, wherein the ground contact and the second contact are both one, and the second contact is located at an end of the second swing arm and away from an intersection of the second swing arm and the first swing arm.
5. The radio frequency micro mechanical switch according to claim 1, wherein an insulating medium layer is disposed on the substrate, a plurality of cantilever beams are disposed on the substrate, the cantilever beams correspond to the first contact portions and the second contact portions one to one, one end of each cantilever beam is fixed on the insulating medium layer, the other end of each cantilever beam is a free end, and the free end drives the corresponding first contact portion or the corresponding second contact portion to swing in a horizontal direction.
6. The rf micro-mechanical switch of claim 5, wherein the conducting line is disposed on the cantilever beam, the first contact portion and the second contact portion are disposed on the side of the free end of the cantilever beam corresponding thereto, and the signal line contact and the ground line contact are disposed near the free end of the cantilever beam.
7. The rf micro-mechanical switch of claim 6, further comprising a piezoelectric driving plate disposed on each of the cantilever beams to drive the corresponding cantilever beam to move in a horizontal direction, wherein each of the piezoelectric driving plates and the first contact portion or the second contact portion of the corresponding cantilever beam are respectively located on two opposite sides of the cantilever beam in the horizontal direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810066726.3A CN108417453B (en) | 2018-01-24 | 2018-01-24 | Radio frequency micro mechanical switch and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810066726.3A CN108417453B (en) | 2018-01-24 | 2018-01-24 | Radio frequency micro mechanical switch and manufacturing method thereof |
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| Publication Number | Publication Date |
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| CN108417453A CN108417453A (en) | 2018-08-17 |
| CN108417453B true CN108417453B (en) | 2020-05-15 |
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| CN201810066726.3A Active CN108417453B (en) | 2018-01-24 | 2018-01-24 | Radio frequency micro mechanical switch and manufacturing method thereof |
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Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20070074728A (en) * | 2006-01-10 | 2007-07-18 | 삼성전자주식회사 | Micro-electro-mechanical systems switch |
| KR100997685B1 (en) * | 2008-05-28 | 2010-12-02 | 광운대학교 산학협력단 | Piezoelectric rf mems switch and fabrication method thereof |
| CN102324344B (en) * | 2011-05-27 | 2013-10-30 | 东南大学 | Radio-frequency micromechanical switch with bidirectional push-pull comb-tooth unit |
| CN105098305B (en) * | 2015-08-27 | 2018-06-19 | 清华大学 | Distributed list resistance attenuator |
| CN107437484A (en) * | 2017-07-24 | 2017-12-05 | 中北大学 | A kind of RF MEMS Switches with spring beam contact |
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