CN111180837A

CN111180837A - Anti-adhesion radio frequency mechanical switch and preparation method thereof

Info

Publication number: CN111180837A
Application number: CN202010058134.4A
Authority: CN
Inventors: 姜理利; 王雷; 李�杰
Original assignee: CETC 55 Research Institute
Current assignee: CETC 55 Research Institute
Priority date: 2020-01-19
Filing date: 2020-01-19
Publication date: 2020-05-19
Anticipated expiration: 2040-01-19
Also published as: CN111180837B

Abstract

The invention provides an anti-adhesion radio frequency mechanical switch and a preparation method thereof, wherein the anti-adhesion radio frequency mechanical switch comprises a substrate; the coplanar waveguide structure is arranged on the substrate and is used for transmitting radio frequency and microwave signals; the cantilever beam structure comprises a cantilever beam, an inductance array and a contact; one end of the cantilever beam is connected with the coplanar waveguide structure through a support, and the other end of the cantilever beam is provided with a contact; the inductor array is arranged on the cantilever beam; the driving structure comprises an inductor and a bonding pad, and the inductor is arranged on the substrate; the inductor is connected with the bonding pad through a metal wire. According to the invention, the radio frequency mechanical switch is actively separated from the adhesion state through the cantilever beam structure, and the problem of switch failure caused by the contact adhesion problem along with the increase of power in the use process of the radio frequency mechanical switch is avoided.

Description

Anti-adhesion radio frequency mechanical switch and preparation method thereof

Technical Field

The invention relates to the technical field of electronic devices, in particular to an anti-adhesion radio frequency mechanical switch and a preparation method thereof.

Background

Radio frequency micro mechanical switches have been studied internationally for over twenty years. From the switch mode, the radio frequency micro mechanical switch can be roughly divided into two types, (1) the general structure of the contact switch is: the signal line is controlled to be in contact or disconnected by adopting an electrostatic or other driving mode, the on-off effect of the switch is controlled, and the isolation degree is determined by the parasitic capacitance of the disconnected part. The parasitic capacitance of the contact switch increases rapidly with the increase of the frequency, which leads to the rapid deterioration of the isolation of the switch; (2) the general structure of a capacitive switch is: the movement of the membrane bridge is controlled in an electrostatic driving mode, so that the effect of changing the size of capacitance bridged between the signal line and the ground wire is achieved, and the on-off of signals is controlled. Capacitive switches exhibit higher isolation in a certain frequency range than ordinary touch switches, and the isolation is determined by the parasitic resistance of the membrane bridge. And due to the skin effect, as the frequency increases, the parasitic resistance rapidly deteriorates to cause the isolation thereof to decrease.

Therefore, an important reliability issue of radio frequency micro mechanical switches is the adhesion issue of the contacts. The surface state, contact fatigue, large current and the like of the contact easily cause the adhesion of the contact, so that the switch fails.

Disclosure of Invention

In order to solve the problems, the invention provides an anti-adhesion radio frequency mechanical switch, which realizes the active separation of the radio frequency mechanical switch from an adhesion state through a cantilever beam structure, and avoids the switch failure problem caused by the contact adhesion problem along with the increase of power in the use process of the radio frequency mechanical switch.

In order to achieve the above purpose, the invention adopts a technical scheme that:

an anti-stiction radio frequency mechanical switch, comprising: a substrate; the coplanar waveguide structure is arranged on the substrate and is used for transmitting radio frequency and microwave signals; the cantilever beam structure comprises a cantilever beam, an inductance array and a contact; one end of the cantilever beam is connected with the coplanar waveguide structure through a support, and the other end of the cantilever beam is provided with a contact; the inductor array is arranged on the cantilever beam; the driving structure comprises an inductor and a bonding pad, the inductor is arranged on the substrate, and the inductor is positioned below the cantilever beam; the bonding pad is arranged on the substrate; the inductor is connected with the bonding pad through a metal wire.

Further, the coplanar waveguide structure comprises an input signal line, an output signal line and a ground line which are arranged on the substrate, and the input signal line is connected with the cantilever beam through a support; the output signal line is located below the contact; the ground lines are two, the input signal line and the output signal line are located between the two ground lines, and the input signal line, the output signal line and the ground lines are parallel to each other.

The invention also provides a preparation method of the anti-adhesion radio frequency mechanical switch, which comprises the following steps: s10 sputtering metal on the substrate and etching to form a coplanar waveguide structure and a driving structure; s20, coating a layer of sacrificial layer on the coplanar waveguide structure and the driving structure and etching the position of a contact on the sacrificial layer; s30, sputtering a layer of metal on the sacrificial layer and etching a cantilever beam structure, and then electroplating for thickening; s40, removing the sacrificial layer by adopting a wet etching method, releasing the structure and obtaining the anti-adhesion radio frequency mechanical switch; the cantilever beam structure comprises a cantilever beam, an inductance array and a contact; one end of the cantilever beam is connected with the coplanar waveguide structure through a support, and the other end of the cantilever beam is provided with a contact; the inductor array is arranged on the cantilever beam.

Furthermore, the driving structure comprises an inductor and a bonding pad, wherein the inductor is arranged on the substrate and is positioned below the cantilever beam; the bonding pad is arranged on the substrate; the inductor is connected with the bonding pad through a metal wire.

Furthermore, the sacrificial layer is made of an organic polymer material with stable high temperature resistance, insulating property and chemical property.

Further, the organic polymer material is polyimide.

Compared with the prior art, the technical scheme of the invention has the following advantages:

(1) the radio frequency mechanical switch is actively separated from the adhesion state through the cantilever beam structure, and switch failure caused by the problem of contact adhesion along with power increase in the use process of the radio frequency mechanical switch is avoided. The anti-adhesion radio frequency mechanical switch is simple in structure and high in reliability.

(2) The preparation method of the anti-adhesion radio frequency mechanical switch is compatible with the preparation method of the traditional switch, no additional process step is needed, and the preparation method is simple.

Drawings

The technical solution and the advantages of the present invention will be apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings.

FIG. 1 is a top view of an anti-stiction RF mechanical switch according to an embodiment of the invention;

3 FIG. 32 3 is 3 a 3 cross 3- 3 sectional 3 view 3 A 3- 3 A 3' 3 of 3 FIG. 31 3 in 3 accordance 3 with 3 one 3 embodiment 3 of 3 the 3 present 3 invention 3; 3

FIG. 3 is a schematic diagram of a cantilever beam structure of an anti-stiction RF mechanical switch according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of an anti-stiction RF mechanical switch driving structure according to an embodiment of the invention;

FIG. 5 is a flow chart of a method for fabricating an anti-stiction RF mechanical switch according to an embodiment of the invention;

fig. 6-8 are diagrams illustrating a process for manufacturing an anti-stiction rf mechanical switch according to an embodiment of the invention.

Reference numerals in the figures

1-substrate, 21-input signal line, 22-output signal line, 23-ground line, 31-cantilever beam, 32-inductor array, 33-contact, 34-support, 41-inductor, 42-bonding pad and 43-metal wire.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The present embodiment provides an anti-stiction rf mechanical switch, as shown in fig. 1, comprising a substrate 1, a coplanar waveguide structure, a cantilever beam structure, and a driving structure.

The coplanar waveguide structure includes an input signal line 21, an output signal line 22, and a ground line 23 disposed on the substrate 1. The ground lines 23 have two, the input signal line 21 and the output signal line 22 are located between the two ground lines 23, and the input signal line 21, the output signal line 22 and the ground lines 23 are parallel to each other. The coplanar waveguide structure is used for transmitting radio frequency and microwave signals;

as shown in fig. 2 to 3, the cantilever arm structure includes a cantilever beam 31, an inductance array 32, and a contact 33. One end of the cantilever beam 31 is connected with the input signal line 21 through a support 34, the other end of the cantilever beam 31 is provided with a contact 33, and the output signal line 22 is positioned below the contact 33. The inductor array 32 is disposed on the cantilever beam 31.

As shown in fig. 4, the driving structure includes an inductor 41 and a pad 42 disposed on the substrate 1, where the inductor 41 is located below the cantilever beam 31. The inductor 41 is connected to the pad 42 by a wire 43.

As shown in fig. 5 to 8, an embodiment of the present invention further provides a method for manufacturing an anti-adhesion rf mechanical switch, including the following steps: s10 sputtering metal on the substrate and etching to form coplanar waveguide structure and drive structure. S20 coating a sacrificial layer 5 on the coplanar waveguide structure and the driving structure and scribing the location of the contact 33 on the sacrificial layer 5. S30 sputtering a layer of metal on the sacrificial layer 5 and etching the cantilever beam structure, then electroplating to thicken. And S40, removing the sacrificial layer 5 by adopting a wet etching method, releasing the structure and obtaining the anti-adhesion radio frequency mechanical switch.

The coplanar waveguide structure comprises an input signal line 21, an output signal line 22 and a ground line 23 which are arranged on the substrate 1, wherein the input signal line 21 is connected with the cantilever beam 31 through a support 34. The output signal line 22 is located below the contact 33; the ground lines 23 have two, the input signal line 21 and the output signal line 22 are located between the two ground lines 23, and the input signal line 21, the output signal line 22 and the ground lines 23 are parallel to each other.

The cantilever beam structure includes a cantilever beam 31, an inductive array 32, and a contact 33. One end of the cantilever beam 31 is connected with the input signal line 21 through a support 34, and the other end of the cantilever beam 31 is provided with a contact 33. The inductor array 32 is disposed on the cantilever beam 31.

The driving structure comprises an inductor 41 and a bonding pad 42 which are arranged on the substrate, wherein the inductor 41 is positioned below the cantilever beam 31. The inductor 41 is connected to the pad 42 by a wire 43.

The sacrificial layer 5 is made of an organic polymer material with stable high temperature resistance, insulating property and chemical property. Polyimide is preferred as the organic polymer material in this embodiment.

The above description is only an exemplary embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structures or equivalent processes that are transformed by the content of the present specification and the attached drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. An anti-stiction RF mechanical switch, comprising:

a substrate (1);

a coplanar waveguide structure arranged on the substrate (1) for transmitting radio frequency and microwave signals;

a cantilever structure comprising a cantilever (31), an inductive array (32) and a contact (33); one end of the cantilever beam (31) is connected with the coplanar waveguide structure through a support (34), and the other end of the cantilever beam (31) is provided with a contact (33); the inductance array (32) is arranged on the cantilever beam (31);

a driving structure comprising an inductor (41) and a pad (42), the inductor (41) being disposed on the substrate (1), the inductor (41) being located below the cantilever beam (31); the pad (42) is disposed on the substrate (1); the inductor (41) is connected to the pad (42) via a wire (43).

2. The anti-stiction rf mechanical switch according to claim 1, characterized in that the coplanar waveguide structure comprises an input signal line (21), an output signal line (22) and a ground line (23) arranged on the substrate (1), the input signal line (21) being connected to the cantilever beam (31) through a support (34); the output signal line (22) is located below the contact (33); the ground lines (23) are two, the input signal line (21) and the output signal line (22) are located between the two ground lines (23), and the input signal line (21), the output signal line (22) and the ground lines (23) are parallel to each other.

3. A preparation method of an anti-adhesion radio frequency mechanical switch is characterized by comprising the following steps:

s10 sputtering metal on the substrate and etching to form a coplanar waveguide structure and a driving structure;

s20, coating a sacrificial layer (5) on the coplanar waveguide structure and the driving structure, and carving the position of a contact (33) on the sacrificial layer (5);

s30, sputtering a layer of metal on the sacrificial layer (5) and etching a cantilever beam structure, and then electroplating for thickening; and

s40, removing the sacrificial layer (5) by adopting a wet etching method, releasing the structure and obtaining the anti-adhesion radio frequency mechanical switch;

wherein the cantilever beam structure comprises a cantilever beam (31), an inductance array (32) and a contact (33); one end of the cantilever beam (31) is connected with the coplanar waveguide structure through a support (34), and the other end of the cantilever beam (31) is provided with a contact (33); the inductance array (32) is arranged on the cantilever beam (31).

4. The anti-stiction radio frequency mechanical switch according to claim 3, characterized in that said actuation structure comprises an inductor (41) and a pad (42), said inductor (41) being arranged on said substrate (1), said inductor (41) being located under said cantilever beam (31); the pad (42) is disposed on the substrate (1); the inductor (41) is connected to the pad (42) via a wire (43).

5. The anti-stiction rf mechanical switch according to claim 3, characterized in that the coplanar waveguide structure comprises an input signal line (21), an output signal line (22) and a ground line (23) arranged on the substrate (1), the input signal line (21) being connected to the cantilever beam (31) through a support (34); the output signal line (22) is located below the contact (33); the ground lines (23) are two, the input signal line (21) and the output signal line (22) are located between the two ground lines (23), and the input signal line (21), the output signal line (22) and the ground lines (23) are parallel to each other.

6. The anti-adhesion RF mechanical switch according to claim 3, wherein the sacrificial layer (5) is made of an organic polymer material with stable high temperature resistance, insulation performance and chemical property.

7. The anti-stiction rf mechanical switch according to claim 6, wherein the organic polymer material is polyimide.