CN103552974B

CN103552974B - With the MEMS electrostatic drive-type cantilever beam structure of camber beam electrical actuator

Info

Publication number: CN103552974B
Application number: CN201310565414.4A
Authority: CN
Inventors: 唐洁影; 蒋明霞; 王磊
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2013-11-14
Filing date: 2013-11-14
Publication date: 2015-12-09
Anticipated expiration: 2033-11-14
Also published as: CN103552974A

Abstract

The invention relates to a MEMS electrostatically driven cantilever beam structure with a curved beam electrothermal actuator, including a substrate, an anchor area of the cantilever beam, a cantilever beam, an electrostatic pull-down electrode and a contact electrode coated on the surface of the substrate, and a curved beam Electrothermal actuator. The curved beam electrothermal actuator is composed of an anchor area and two curved beam branches that can be expanded when energized; the curved beam is suspended above the substrate and near the end of the cantilever beam through the support of the two anchor areas connected at the ends of the branches Underneath, after energizing and heating, the bent end can extend forward. The invention provides a cantilever beam structure that can effectively solve the problem of adhesion failure, adding a curved beam electrothermal actuator to eliminate adhesion from the structural design, and improving the defects of high failure rate, difficult maintenance and low efficiency caused by adhesion , improve the stability and reliability of operation, and have important practical value.

Description

With the MEMS electrostatic drive-type cantilever beam structure of camber beam electrical actuator

Technical field

The present invention relates to a kind of MEMS cantilever beam structure, be specifically related to a kind of MEMS electrostatic drive-type cantilever beam structure with camber beam electrical actuator.

Background technology

MEMS(microelectromechanical systems) referring to can batch making, integrates micro mechanism, microsensor, micro actuator and signal transacting with control circuit until interface, to communicate and the microdevice of power supply etc. or system.

MEMS technology mainly belongs to micron technology category.Cantilever beam structure is typical micro mechanical structure, and characteristic size is micron dimension, and skin effect is remarkable, and integrity problem is the key factor of its development of restriction.Utilize the cantilever beam structure that surface processing technique manufactures, spacing between movable beam and substrate is smaller, be about zero point several to several microns, and length is much larger than thickness, in processing and use procedure, the rigidity of structure reduces, and is easy to that beam is out of shape and bends to substrate, be sticked together with substrate, there is adhesion, cantilever beam cannot normally be worked.Simultaneously some cantilever beam structure only has and fully contacts with substrate, the performance that guarantee is excellent.Such as, no matter common RFMEMS switch is capacitance-type switch, or direct contact type switch, and excellent contact performance can reduce the loss of signal greatly.

For solving adhesion failure problem, currently mainly to start with from prevention, when structure manufactures, by making salient point to reduce contact area when movable beam and substrate contact at substrate surface, reduce the risk adhered to, but be difficult to eliminate adhesion completely, ensure the reliability of cantilever beam work.Therefore, be necessary a kind of method proposing solution adhesion failure newly, guarantee the premium properties of cantilever beam.

Summary of the invention

For not being specifically designed to the device eliminating sticking problem at present, adhesion failure problem is not yet effectively solved, and technical problem to be solved by this invention is to provide a kind of cantilever beam structure that effectively can solve adhesion failure problem.The present invention aims to provide a kind of MEMS cantilever beam structure with camber beam electrical actuator, mainly between cantilever beam and substrate, settles camber beam electrical actuator to eliminate adhesion.The present invention also provides this structure to eliminate the specific works mode adhered to.

For achieving the above object, the technical solution adopted in the present invention is as follows:

A kind of MEMS electrostatic drive-type cantilever beam structure with camber beam electrical actuator, comprise substrate, the anchor district be connected with cantilever beam one end, cantilever fine strain of millet, be positioned at electrostatic pull-down electrode immediately below cantilever beam be positioned at cantilever beam end contact electrode, wherein cantilever beam is suspended on the top of substrate by anchor district, pull-down electrode is coated on the upper surface of substrate with contacting electrode, it is characterized in that: the upper surface of described substrate is also provided with the camber beam electrical actuator of anchor district and camber beam composition, this camber beam is made up of two branch beam, the two ends of camber beam are connected with the anchor district of cantilever beam both sides and are suspended in the top of substrate, and this camber beam is positioned at the below of cantilever beam, the junction of two branch beam to be positioned at immediately below cantilever beam and near cantilever beam end

The present invention settles camber beam electrical actuator between cantilever beam and substrate, by applying voltage between the anchor district, two ends of camber beam, makes electric current flow through camber beam, camber beam branch extends to bending end, progressively cut the below of the cantilever beam end adhered to, make cantilever beam and substrate desquamation, finally eliminate adhesion.

Beneficial effect of the present invention is as follows:

The present invention just considers to adhere to removing function at the beginning of structural design, and the design of an additional curved thermal actuator in conventional MEMS cantilever beam structure provides a kind of selection newly for eliminating adhesion;

Utilize the thermal expansion of camber beam electrical actuator, make the cantilever beam adhering to substrate surface be subject to the effect of tangential peeling force, solve adhesion failure problem, improve the operation stability of cantilever beam structure, improve availability, reduce maintenance cost;

The present invention addition of adhesion cancel system, adheres to eliminate while function in increase, to the normal operation of MEMS cantilever beam itself without any negative effect.Ensure that the premium properties of cantilever beam, improve operational efficiency that there is important practical value.

Accompanying drawing explanation

Fig. 1 is the schematic side view of structure cantilever beam of the present invention and substrate contact state;

Fig. 2 is the structural representation after the present invention removes camber beam and cantilever beam;

Fig. 3 is the schematic top plan view of structure of the present invention;

Wherein there are two branch beam of the anchor district 2 of substrate 1, cantilever beam, cantilever beam 3, pull-down electrode 4, substrate contact electrode 5, first anchor district 61 and the second anchor district 62, cantilever beam camber beam: the first branch beam 71 and the second branch beam 72.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the present invention is further described:

The present invention can utilize conventional MEMS surface processing technique to prepare, and substrate is monocrystalline silicon, cantilever beam and camber beam material identical, can be doping polysilicon, also can be metal.Pull-down electrode, contact electrode are metal material gold or aluminium is made.

The present invention relates to a kind of MEMS cantilever beam structure with camber beam electrical actuator, as shown in Figure 1-Figure 3, this structure comprises substrate 1, the anchor district 2 of cantilever beam, cantilever fine strain of millet 3, pull-down electrode 4, contact electrode 5 and camber beam electrical actuator; The top of substrate 1 is the anchor district 2 of cantilever beam, and cantilever beam 3 is suspended on the top of substrate 1 by anchor district 2, and pull-down electrode 4 is coated on the upper surface of substrate 1; At the upper surface of substrate 1, contact electrode 5 is also set, and contact electrode 5 is positioned at the below near cantilever beam 3 end; Camber beam electrical actuator is positioned at the upper surface of substrate 1 and the below of cantilever beam 3, camber beam electrical actuator is made up of anchor district and camber beam, anchor district is positioned at the upper surface of substrate 1 and the both sides of cantilever beam 3, anchor district connects the expandable camber beam of energising, camber beam is positioned at the below near the top of substrate 1 and cantilever beam 3 end, and the junction of two branch beam is positioned at immediately below cantilever beam 3.

General principle of the present invention utilizes camber beam electrical actuator, produces thermal expansion by Ohmic heating, and the top of bending place travels forward, and incision adheres to the below of the cantilever beam end of substrate surface, reaches the object eliminated and adhere to.In test, between cantilever beam 3 and substrate contact electrode 5, there is adhesion when cannot upspring, start camber beam electrical actuator.Between two clamped ends of camber beam, apply voltage, make electric current flow through two branches of camber beam.Two branches of camber beam expand because of Ohmic heating, and the bending end to camber beam extends, and camber beam produces in-plane displacement.Voltage is larger, and the electric current flowing through camber beam is larger, and the in-plane displacement that camber beam produces is also larger.Initial voltage is a few volt, progressively increases voltage, until bending end cuts the below of cantilever beam 3 end adhered to.By the consideration in structural design, improve cantilever beam structure run in the fault rate that causes of adhesion failure high, Maintenance Difficulty, inefficient defect.

By measuring the resistance between substrate contact electrode 5 and cantilever beam 3, check whether cantilever beam 3 adheres to substrate 1 phase.If resistance value is greater than M Ω magnitude, show cantilever beam and substrate separation, adhering disintegration removes.If the resistance value measured is less than 10 ²the magnitude of Ω, shows that cantilever beam and substrate still exist and contacts.Adhere to and do not remove, repeat above-mentioned steps; Adhere to and remove, then remove the voltage that bending beam applies, camber beam electrical actuator quits work.

The present invention utilizes camber beam electrical actuator to produce thermal expansion, impels to adhere to and eliminates, make cantilever beam fully can contact with substrate simultaneously, efficiently solve the adhesion failure problem of cantilever beam.Salient point is made at contact surface more perfect and effective with the settling mode reducing two contact surface area than tradition.Improve stability and the reliability of running, ensure that its premium properties, there is important practical value.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims

1. A MEMS electrostatically driven cantilever beam structure with a curved beam electrothermal actuator, including a substrate (1), an anchor area (2) connected to one end of the cantilever beam, a cantilever beam (3), and a cantilever beam (3) ) directly below the electrostatic pull-down electrode (4) and the contact electrode (5) located below the end of the cantilever beam (3), wherein the cantilever beam (3) is suspended above the substrate (1) through the anchor region (2), and the pull-down electrode (4) and the contact electrode (5) are coated on the upper surface of the substrate (1), characterized in that: the upper surface of the substrate (1) is also provided with a first anchor area (61), a second anchor area (62) and a curved beam electrothermal actuator composed of a first branch beam (71) and a second branch beam (72), the two ends of the curved beam and the first anchorage area on both sides of the cantilever beam (61) is connected to the second anchor area (62) and suspended above the substrate (1), and the curved beam is located below the cantilever beam (3); the first branch beam (71) and the second branch beam (72 ) is located directly below the cantilever beam (3) and close to the end of the cantilever beam.