CN1929067B - Switch - Google Patents
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- CN1929067B CN1929067B CN2006101261343A CN200610126134A CN1929067B CN 1929067 B CN1929067 B CN 1929067B CN 2006101261343 A CN2006101261343 A CN 2006101261343A CN 200610126134 A CN200610126134 A CN 200610126134A CN 1929067 B CN1929067 B CN 1929067B
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Abstract
A switch comprises voltage applying means for providing direct current potentials to first to third beams arranged with a spacing slightly distant one from another, and electrodes for inputting/outputting signals to/from the beams. By controlling the direct current potential provided to the beam, an electrostatic force is caused to thereby change the beam positions and change a capacitance between the beams. By causing an electrostatic force between the first and second beams and moving the both beams, the first and second beams can be electrically coupled together at high speed. Also, an electrostatic force is caused on the third beam arranged facing to the first and second beams, to previously place it close to the first and second beams. When the electrostatic force is released from between the first and second beams, the second beam moves toward the third beam thereby releasing the first and second beams of an electric coupling.
Description
The application be the applicant on July 25th, 2003 submit to, application number for " 03133185.8 ", denomination of invention divides an application for the application for a patent for invention of " switch ".
Technical field
Thereby the present invention relates to be used for circuit, utilize the power that applies by the outside that electrode machinery is moved to allow signal pass through or with the switch of its disconnection.
Background technology
As the circuit switch, the switch that has air bridges (air bridge) is used in known having.In Figure 16,124 is the electrode of movable air bridges, 126,128 for forming on substrate 129 respectively, and the electrostatic force by electrode 126,128 and 124 generations of air bridges makes air bridges 124 move horizontally to electrode 126 or 128.If signal is input air bridge 124, and then air bridges 124 is electrically connected with electrode 126 or 128 at electrode, makes the signal disconnection or passes through, and it moves (for example referring to Patent Document 1) as switch.
In addition, the known microelectromechanicpositioning RF switch that has as shown in figure 17.Microelectromechanicpositioning RF switch 210 has following structures, promptly forms the repeatedly spring suspension device 222 of bending on substrate 221, and suspension compact platform 220 thereon.This compact platform 220 times forms holding wire, adds DC potential at holding wire and 220 one of compact platforms, just produces electrostatic force, and then platform 220 is attracted by holding wire.At this moment,, the internal residual stress of the material that constitutes beam is almost discharged by the repeatedly bending part of spring, play the effect (for example referring to Patent Document 2) of mechanical stress buffer by repeatedly bending spring structure.
[patent documentation 1]
The spy opens the 2001-84884 communique
[patent documentation 2]
The spy opens the 2001-143595 communique
But, in the structure of above-mentioned patent documentation 1, drive under the situation of air bridges 124 with electrostatic force, in order to realize the isolation of bigger signal, the interval that adds large electrode 126,128 and air bridges 124, but because electrostatic force is directly proportional with negative 2 powers of distance, so electrostatic force reduces, the response time does not just reach the value of hope.In addition, in order to remedy the minimizing of electrostatic force, it is that applied voltage is increased that a kind of method is also arranged, and still, for requiring the wireless communication devices that power consumption is little, driving voltage is low, increasing applied voltage is not a kind of desirable method.
In addition,, will the rigidity to electrostatic force be strengthened as a string of tightening if there is tensile stress to exist, draw in (pull-in) voltage (the attraction voltage that depends on electrostatic force) and improve in the inside of beam because air bridges 124 is girder constructions of straight line.And temperature one rises, and the internal stress of beam might be transformed into compression stress again, produces buckling.That is, the ambient temperature as can not be to the residual stress that produces in the production process, switch motion the time is carried out certain management, just can't guarantee stable switch motion characteristic.
On the other hand, in the compact platform structure of patent documentation 2, be divided into zone and bending spring suspension structural portion (flexing structure (flexure)) in order to relax stress with the holding wire coupling.Promptly be provided with the additional structure that is used to relax internal stress.From the Newton's equation of motion formula as can be known: when the member with quality m was applied same power, quality m was more little, and the acceleration that member produces is big more.Therefore, in described structure, because added the flexing structure, so quality m increase, so there is the fast inadequately problem of response speed.In addition, the flexing structure is soft more, can alleviate the constraint of the support sector that platform 220 is subjected to more, so if having stress gradient at the thickness direction of film, then because Stress Release upwarps platform 220, leave substrate 221.As not reproducing this stress gradient value accurately, then the degree of this warpage is just inconsistent in the manufacturing process of beam, just can not suppress discrete the discrete of pull-in voltage increase that reach that the electric capacity between platform 220 and holding wire reduces.In addition, as utilizing the semiconductor technology manufacturing, is the electric conductor of commaterial because of beam and flexing structure then, so the circuit impedance of this flection part just can not be ignored in high-frequency circuit.
In addition, if variation of ambient temperature is then different with the material coefficient of thermal expansion coefficient of beam because of baseplate material, can produce thermal stress.Though the generation reason of this thermal stress is different from the residual stress in the aforementioned manufacturing process, can cause the phenomenon of " being out of shape along with the Stress Release of beam " equally, therefore must consider its influence to static capacity and pull-in voltage.
The present invention system proposes in view of above all points, and its purpose is to provide a kind of switch that can realize the shortening response time and reduce applied voltage.
In addition, purpose is to provide a kind of discrete switch that can realize not having the pull-in voltage increase.
In addition, purpose is to provide a kind of can the inhibition to change the switch that causes that switching characteristic changes because of the internal stress of beam.
Summary of the invention
Switch of the present invention comprises the the 1st, the 2nd, the 3rd beam with the arranged spaced of only separating a little mutually, the applied voltage device that independently provides DC potential to use for aforementioned beam is added electrostatic force, and be located at the electrode that each beam input and output AC signal is used on each beam.Make the change in location of each root beam by electrostatic force, the static capacity between beam is changed.
According to this configuration, produce electrostatic force by making between the 1st, the 2 two beam, make the 1st, the 2 two beam all movable, thereby Liang Nenggeng is electric coupling at high speed, and, separate at high speed in order to make beam, by on the 3rd beam that is oppositely arranged with the 2nd beam, producing electrostatic force, and in advance near the 1st and the 2nd beam, because can between the 2nd and the 3rd beam, apply stronger electrostatic force, so can respond more at high speed.
In addition, the present invention is designed to identical shaped bending by making beam, and the variation that makes internal stress with beam change corresponding pull-in voltage obtains relaxing, and simultaneously, also can relax the variation of static capacity between the beam that the distortion of beam causes.
Thus, can utilize SEMICONDUCTING THIN FILM TECHNOLOGY to constitute low-voltage, high-speed driving and be subjected to residual stress and thermal expansion and the little microminiature variable capacitance type switch of characteristic variations that produces.
Description of drawings
Fig. 1 is the concise and to the point oblique view that constitutes of switch of expression the invention process form 1.
Fig. 2 (a) is the switch connecting circuit figure of the invention process form 1.
Fig. 2 (b) is the switch equivalent circuit diagram of the invention process form 1.
Fig. 3 (a) to (f) is the schematic diagram of the switch motion of explanation the invention process form 1.
Fig. 4 (a) to (f) is the profile of an example of the switch manufacturing process of expression the invention process form 1.
Fig. 5 is the profile of the switch pith of expression the invention process form 2.
Fig. 6 is the switch connecting circuit figure of the invention process form 3.
Fig. 7 is the concise and to the point profile that constitutes of switch of expression the invention process form 3.
Fig. 8 (a) and (b) are the concise and to the point oblique view and the plane graph that constitutes of switch of expression the invention process form 4.
The performance plot of Fig. 9 for concerning between the internal stress of the switch central sill of expression the invention process form 4 and pull-in voltage.
The performance plot of Figure 10 for concerning between static capacity between the internal stress of the switch central sill of expression the invention process form 4 and beam.
The profile that Figure 11 uses for manufacture method example of switch of explanation the invention process form 4.
The performance plot that concerns between the 1 rank resonance frequency of Figure 12 for the internal stress of the switch central sill of expression the invention process form 4 and beam.
Figure 13 (a) is the schematic diagram of the concise and to the point formation under the applied voltage state not on the electrode of switch that is illustrated in the invention process form 5.
Figure 13 (b) is the schematic diagram of the concise and to the point formation under the applied voltage state on the electrode of switch that is illustrated in the invention process form 5.
The performance plot of Figure 14 for concerning between the applied voltage of the movable body material of the switch of expression the invention process form 5 and internal stress.
Figure 15 is the schematic diagram of the method for controlling switch of explanation the invention process form 5.
Figure 16 is the stereogram of an example of expression switch in the past.
Figure 17 is the stereogram of an example of expression other switch in the past.
Label declaration
1,2,3,31,32,33,81,82,83 beams
4～9 electrodes
41 High Resistivity Si substrates
42 silicon oxide layers
43 silicon nitride films
44 silicon oxide layers
45 sacrifice layers
The 46Al layer
47 photoresist figures
48,51 beams
49 gaps
50 silicon nitride films
84,85 anchors (anchor) portion
86 photoresists
87,88 inculating crystal layers (seed layer)
89 switches
90 anode electrodes
101 input terminals
102 lead-out terminals
103 movable bodys
104 movable electrodes
105 electrodes
Concrete example
Main points of the present invention are, by electrostatic force the relative position of three beams are changed, and make that static capacity changes between beam, thereby carry out electric coupling or disconnection, in such switch, all movable by making each beam, thus realize energy speed-sensitive switch and the structure of controlling with low DC potential.
In addition, in this structure, make warp architecture by the beam that will constitute switch, thereby relax the variation that changes corresponding pull-in voltage with the internal stress of beam, the while also relaxes the variation of static capacity between the beam that the distortion because of beam causes.
Below, utilize accompanying drawing, describe example of the present invention in detail.
(example 1)
Referring to figs. 1 through Fig. 3, example 1 of the present invention is described.Fig. 1 represents the concise and to the point pie graph of the switch of example 1.1 is that the 1st beam, 2 is that the 2nd beam, 3 is the 3rd beam.Shape that each root beam 1,2,3 usefulness is suitable and material form, and the signal of telecommunication is transmitted losslessly, and the surface is provided with the dielectric film of tens Nano grades.Each beam 1,2,3 for example is made of metals such as aluminium, silver, copper and alloys, and shape for example is the fixing double base girder construction in two ends of thick 2 μ m, wide 2 μ m, long 200 μ m, separately interval, for example spaced and parallel configuration of 0.6 μ m to satisfy the regulation isolation.If beam 1,2,3 is the double base girder construction not necessarily, also can be single backbar.In addition, by making the change of shape of beam 1,2,3, and the spring constant of beam is changed.Also have, each beam 1,2,3 adopts and can make internal stress try one's best little structure and technology.This will describe in detail in the back.
The two ends receiving electrode 4,7 of beam 1, the two ends receiving electrode 5,8 of beam 2, the two ends receiving electrode 6,9 of beam 3.
For the ease of later explanation, for example electrode 5 is added input signal as input terminal, electrode 7 connects antenna end as lead-out terminal, and electrode 9 connects 50 Ω terminal resistances, is that example describes with such situation.Fig. 2 (a) represents connecting circuit, and Fig. 2 (b) represents its equivalent electric circuit.In the following description, during so-called switch ON, mean the state that electrode 5 is connected with electrode 7 in Fig. 2 (a); During switch OFF, mean the state that in Fig. 2 (a), electrode 5 and electrode 7 disconnections, electrode 5 is connected with electrode 9.
According to the structure of Fig. 2 (a) and Fig. 2 (b), when switch OFF,,, therefore do not produce reflected wave because terminal is 50 Ω from the angle of input terminal.Individual in addition when switch OFF, C
1Impedance become big, and C
2Impedance diminish, so the signal of input terminal input passes through C
2And 50 Ω grounding through resistances, thereby make as the electrode 7 of antenna terminal and bigger as the isolation between the electrode 5 of input terminal.At this moment, also can be as required between input signal source and the electrode 5 as input terminal, and as the electrode 7 of lead-out terminal and antenna end between dispose electric capacity.Also have,, also can not establish 50 Ω resistance and direct ground connection in order to improve isolation more.
In addition, also electrode 9 terminal be can not be connect and other lead-out terminal, the dispense switch of the single input of realization dual output connected.In addition, as with electrode 5 as lead-out terminal, with electrode 7 and 9 as input terminal from antenna, then also can import-selector switch of single output as double antenna.
Utilize Fig. 3 that switch motion is described.Fig. 3 (a) is illustrated in the switch of Fig. 1 on each electrode 4～9 the not state of applied voltage.Then, in order to make signal be coupled to antenna terminal from input terminal, in Fig. 3 (b), if the response time in regulation makes the DC potential of the control voltage source 10 of connection electrode 4 become High, and make the DC potential of the control voltage source 12 of the DC potential of control voltage source 11 of splicing ear 5 and connection electrode 6 become Low respectively in the response time of regulation, then,, beam 1 contacts so attracting each other with beam 2 because between beam 1 and beam 2, produce electrostatic force.
At this moment, if beam 1 makes identical shape with beam 2, spring constant and quality are also identical, and then beam 1 and beam 2 contact at intermediate location.This situation is compared as the situation of fixed electrode with either party with beam 1,2, for identical electrostatic force, because of the displacement of distance between the beam 1,2 becomes twice to change, so just can respond with more speed, in addition, if the identical response time, also just can be with lower voltage control.For example, if the DC potential of the power taking utmost point 4 is 7.25V, then the response time can accomplish below 5 μ s, but only makes under the one-sided movable situation, and the response time becomes 7.4 μ s, and the response time prolongs, and reaches about 1.5 times.Otherwise as in order to accomplish that the response time is 5 μ s, then applied voltage is necessary for 10.3V.
Under the state of Fig. 3 (b), if the DC potential of the control voltage source 12 of the electrode 6 of tie-beam 3 is High, then 2 on beam 3 and beam just produce electrostatic force, and as Fig. 3 (c), beam 3 moves to the direction of beam 2.At this moment, though beam 1,2 move to beam 3 directions too, 1,2 two couplings of beam, therefore the spring constant of equivalence is big, so littler than the amount of movement of beam 3.Here, establishing the DC potential that is added on the electrode 6 is to be lower than the voltage that beam 3 is not drawn in.If aforementioned condition, because pull-in voltage is about 6.7V, in case add the following voltage of this value, the maximum displacement of beam 3 is about 0.15 μ m, and the maximal clearance that beam is 2,3 becomes 0.75 μ m.Because square being inversely proportional to of electrostatic force and distance, so compare when not mobile with beam 3, the electrostatic force increase of beam 3 and 2 generations of beam is 1.4 times.
Also having, also can not be that the state from Fig. 3 (b) is added in DC potential on the electrode 6, but the instantaneous DC potential counter-rotating that makes electrode 4 and electrode 5.Just can make beam 3 and 2 on beam produce electrostatic force without control voltage source 12 external dc current potential again like this.So at this moment can not draw in greatly because of the gap of beam 2,3.
In addition, requiring under the situation of high-isolation, if make the DC potential of control voltage source 12 remain the state of Low, then because beam 3 is not movable, the gap that beam is 2,3 can remain on the state of increase, and the electric coupling of beam 2 and beam 3 is reduced.
Then, cut-out is led to the circuit of electrode 7, is input signal that the switch OFF action that electrode 7 switches to electrode 9 describes from antenna end.
Under the state of Fig. 3 (c), in a single day the DC potential that is added on the electrode 4 becomes Low from High, because of 1,2 on beam does not produce electrostatic force, so as Fig. 3 (d), beam 1 and beam 2 are got back to the home position with the elastic force of self.At this moment, because beam 3 bends towards the direction of beam 2 in advance, so beam 2 as Fig. 3 (e), because the electrostatic force of 2,3 generations of beam and move to the direction of beam 3 at high speed strongly, and is in contact with it.In a single day beam 2 contacts with beam 3, carry out capacitive coupling from the AC signal that the electrode 5 of input terminal is imported by the dielectric film that is arranged on each beam 2,3 surface, passes to beam 3 from beam 2, to electrode 9 outputs.
Like this, when switch OFF, make beam 2 and beam 3 couplings, in Fig. 2 (b), because of C
2Short circuit, signal are difficult to be sent to C
1So, can guarantee higher isolation.
Not making beam 3 in advance when the direction of beam 2 is crooked,, just can not obtain the desirable response time by higher voltage if do not add because of the maximal clearance becomes 0.9 μ m.
Also have, also the same if under the state of Fig. 3 (e) with the situation of Fig. 3 (c), DC potential is added on the electrode 4, make 2 on beam 1 and beam add electrostatic force, then as Fig. 3 (f), beam 1 bends towards beam 2 directions, and the maximal clearance is dwindled.
By above-mentioned switch motion, when ON state and OFF state, add that the beam 2 of signal always contacts with other beam 1 or beam 3, become locking (latch) state.By like this, suppose that when the powerful signal of beam 2 inputs if the state of non-locking, then beam 2 be because the electrostatic force of self might be pulled to beam 1 or beam 3, but now because beam 2 always by beam 1 or beam 3 lockings, so can prevent misoperation.
More than, each beam 1,2,3 is described by the movable in the horizontal direction situation of electrostatic force, arrange but also each beam 1,2,3 can be made in vertical direction, make it movable in vertical direction.Though in addition here with static masterpiece actuating force, also can be for example with effects such as electromagnetic force or piezoelectricity, heat.In addition, except making each beam 1,2,3 moves in air, also can make it in a vacuum, move in the inert gas.
Then, utilize manufacturing process's example of switch of the process profile key diagram 1 of Fig. 4.In Fig. 4 (a), High Resistivity Si substrate 41 heated oxides, at the silicon oxide layer 42 that forms on the substrate 41 about thickness 300nm.Thereon with decompression CVD method, the silicon nitride film 43 of deposit thickness 200nm.Use the silicon oxide layer 44 of decompression CVD method deposit thickness 50nm again.
Then, in Fig. 4 (b), form thickness 2 μ m by spin coating, again after exposure, developing, 140 ℃ of oven dry 10 minutes down, form sacrifice layer 45 with heating plate at the sacrifice layer that on the silicon oxide layer 44 photoresist is constituted.
Then, shown in Fig. 4 (c); On whole of substrate,, form the figure of photoresist 47, make resist remain in the zone of regulation with the Al layer 46 of sputtering method deposit thickness 2 μ m.
Then, shown in Fig. 4 (d), the figure 47 that aforementioned photoresist is formed carries out the dry etching of Al layer 46 as mask, forms beam 48, removes figure 47 and the sacrifice layer 45 that photoresist is formed with oxygen plasma again.Utilize above operation, form the beam 48 that has gap 49 with respect to the surface of substrate 41.
For another example shown in Fig. 4 (e), on the silicon oxide layer 44 of the whole surface of beam 48 and substrate surface, if with the silicon nitride film 50 of plasma CVD deposit thickness 50nm, then on the silicon oxide layer 44 of substrate surface and beam 48 around form silicon nitride film 50.
At last, shown in Fig. 4 (f), by with anisotropic dry etching method being arranged with the thickness more than the aforementioned deposit thickness, 100nm for example, having under the condition of selecting ratio with silicon oxide layer 44, silicon nitride film 50 is carried out etchback (etchback), make its upper surface not have silicon nitride film 50, and form beam 51 only in the corrosion of side residual silicon nitride film 50.
Also have, in this example, be to use High Resistivity Si substrate 41 as substrate, but also available common silicon substrate, compound semiconductor substrate and insulating material substrate.
In addition, on High Resistivity Si substrate 41,, formed silicon oxide layer 42, silicon nitride film 43, silicon oxide layer 44, but, also can save the formation of these dielectric films in the very high occasion of substrate resistance as dielectric film.In addition, on silicon substrate, formed the dielectric film of the such 3-tier architecture of silicon oxide layer 42, silicon nitride film 43, silicon oxide layer 44, but the silicon nitride film of deposit is compared fully thick thickness is arranged on the thickness of silicon nitride film 43 and beam, even and its thickness has been to having experienced under the so-called repeatedly situation that the operation of corrosion does not still disappear, the formation operation of silicon oxide layer 44 can omit.
Also have, in this example, be to use Al as the material that forms beam, but also can be with other metal material, for example Mo, Ti, Au, Cu or also can use the such semi-conducting material of the amorphous silicon that mixes high concentration impurities, the macromolecular material of conductivity etc. is arranged.Also have, be to use sputtering method as film build method, but formation such as also available CVD method, coating method.
(example 2)
Then, with reference to Fig. 5 the 2nd example 2 is described.This example is taked the structure same with the 1st example basically, but the 2nd beam 32 compare with the 1st beam 31, the 3rd beam 33, thin thickness, and for example with the 2nd beam ratio, the 1st beam and the 3rd beam are made thick more than 1.5 times.In this example, when the 1st beam 31 contacts with the 2nd beam 32,, between the 1st beam 31 and the 3rd beam 33, also act on electrostatic force 35 except between the 1st beam 31 and the 2nd beam 32, acting on the electrostatic force 34.Take this structure, as the 1st example, with after the 2nd beam 32 contacts, even DC potential is not added on the electrode 6 again, the 3rd beam 33 still will move to the direction of the 2nd beam 32 at the 1st beam 31.
In addition, at this moment, because the 1st beam 31 is close to the direction of the 3rd beam 33 a little, so the spring constant of the 2nd beam increases, it is not at intermediate location but in a side contacts of more close the 2nd beam 32 that its structure can be made the 1st beam 31 and the 2nd beam 32.
(example 3)
Below, with reference to Fig. 6 and Fig. 7 the 3rd example is described.In this example, as shown in Figure 6, with respect to the switching circuit of antenna terminal 65 balanced configurations a plurality of (among Fig. 6 being 4) Fig. 2 (a).Thus, can realize to be distributed into the input of an antenna single input switches of exporting a plurality of, that can export more more.The switch of this structure can be made arrayed with example 1 used switch as shown in Figure 7, and each switch carried out capacitive coupling and constitutes.Also have, Fig. 7 is for showing the situation of 2 switching circuits.In Fig. 7, the many beams 74 on the electrode 71 form comb shape, between each beam 74 beam 75 are set.Beam 75 is coupled with a plurality of electrodes 72 respectively.With electrode 72 electrode 73 is set relatively.Electrode 71 connects control voltage source 76, and electrode 72 connects control voltage source 77, and electrode 73 connects control voltage source 78.
If the DC potential of the control voltage source 77 that the DC potential of the control voltage source 76 that electrode 71 connects is High, electrode 72 to be connected and the DC potential of the control voltage source 78 that electrode 73 connects are respectively Low, then produce generation capacitive coupling 79, carry out switch motion at beam 74 and beam 75.
In the switch of example 1, requiring fast occasion of response time, the quality of movable beam just must be little.But in the switch of capacity coupled example 3, if the quality of beam is reduced, then capacity coupled sectional area also diminishes, so the degree of coupling reduces, it is big that loss becomes.Therefore, in order to take into account these two mutual opposite characteristics of response time and loss, so all do each root beam very for a short time, to shorten the response time, by these beams are lined up array, increase the degree of coupling of whole switch again, thereby response time and two characteristics of loss all can be satisfied.For example, establish the wide 2.5 μ m of being shaped as of every beam, thick 2.5 μ m, long 380 μ m, when the frequency of AC signal is 5GHz, dispose 5 groups of switches, then can obtain the good characteristic of passing through as parallel connection.
In this example,, has frequency characteristic because be capacitive coupling.If the electric capacity of the series connection side switch shown in the equivalent electric circuit of Fig. 2 is C
1, electric capacity over the ground is C
2, then impedance Z can be represented with (formula 1).C
1And C
2Use substantially the same switch, C
1And C
2Relation with (formula 2) expression.α represents the changes in capacitance ratio, is the ratio of gap between beam and insulator thickness.
[formula 1]
[formula 2]
C
2＝αC
1
If α obtains greatly, because of driving voltage increases, the response time is also elongated, so can not be too big.For example, establishing the insulator thickness is that 10nm, gap are 0.6 μ m, and then α is 60.
In order to ensure isolation, impedance is that maximum condition can be represented C with (formula 3)
1As follows.Getting α and be 60, being suitable for frequency is 5GHz, then C
1Be 4.2PF.Decide the shape of beam in view of the above, then can select the beam of 5 groups of thick 2.5 μ m, wide 2.5 μ m, long 380 μ m for use.
[formula 3]
Therefore in addition, when frequency of utilization was the signal of 1GHz, because of frequency reduces to 1/5, the group number of the beam that adopts also increased by 500 into 25 groups, then can obtain the characteristic that is equal to 5GHz, realized the switch of no frequency characteristic.
According to this example,, can realize having the switch of desirable impedance or electric capacity by a plurality of switch in parallel configurations.
(example 4)
Below, with reference to Fig. 8 to Figure 12 example 4 of the present invention is described.The oblique view of the switch that Fig. 8 (a) relates to for the invention process form 4, Fig. 8 (b) is a plane graph.The 1st beam 81, the 2nd beam 82, the 3rd beam 83 are the double base beam, and its two ends are fixed on the substrate (not shown) by anchor portion 84,85 respectively, the thick t1=t2=t3=2 μ m of beam, wide w1=w2=w3=2 μ m, long L=500 μ m.With the Al of Young's modulus 77GPa material as beam.81,82,83 on each beam keeps the spacing parallel arranging configuration of g=0.6 μ m.On the relative side of adjacent beam, form the thick insulating barrier of about 0.01 μ m, because it is more much smaller than deck-siding, so little to the mechanical property influence of beam.Moreover dielectric film can form in appointing on the one or both sides of relative side.
Shown in Fig. 8 (b), from the top of switch, beam 81,82,83 S-shaped bendings for example are the alphabetical S that presents in 1 cycle with the SIN function of (formula 4).
[formula 4]
But, in Fig. 8 (b),, bending is drawn out turgidly for ease of understanding.In beam, the internal stress Sy of the internal stress Sx of directions X and Y direction does not depend on the position of X, Y, Z, and existing stress is identical.In addition, be isotropic internal stress of Sx=Sy=S.Correctly, the beam of the beam made from semiconductor technology for forming on sacrifice layer though internal stress S is arranged this moment, is the value that discharges after some by removing this internal stress of sacrifice layer S.
With the structure of Fig. 8, between the 1st beam 81 and the 2nd beam 82, add potential difference, when utilizing electrostatic force to make both crooked, the relation between internal stress S and pull-in voltage is as shown in Figure 9.Size to bending compares, and is that the situation of 2,4,6 μ m compares to the value of (formula 4) Δ y promptly.In addition, Δ y=0, the situation of promptly unbending straight beam also illustrates in the lump.Here because one add compression stress, just produce buckling, so only represent stress S in positive scope, i.e. value during tensile stress.Like this, only, can suppress to cause the increase of pull-in voltage because of the increase of internal stress S obviously producing when crooked, this be because bending is big more, be that the value of Δ y is big more, it is also just big more then to suppress effect.
Below, in order to verify the effect of S shape bending, the situation that bending is curved arch is described.The bending of arch is similar to the SIN function half period of (formula 5).If internal stress S and the relation between pull-in voltage during Δ y=4 μ m are shown in Fig. 9 in the lump.
[formula 5]
Clearly, the occasion of arch, S=0～30MPa compares with the S shape of Δ v=2 μ m, and pull-in voltage increases, and the zone more than 30MPa is just close gradually.In the scope of S=0～10MPa, pull-in voltage is bigger than straight beam on the contrary.But near S=20 ± 10MPa, because pull-in voltage is almost certain, so, then have the advantage that pull-in voltage is diminished if can in this scope, suppress the discrete of residual stress.
Below shown in situation be that by adjacent beam is provided with identical bending, the distortion of the beam that causes for internal stress can suppress the variation of static capacity between adjacent beam.Figure 10 is the graph of a relation between internal stress S and static capacity when potential difference is 0V between the adjacent beam of expression, from this figure as can be known, three S shape and the arches that degree of crook is different of drawing, such 4 curves overlapped of image curve W are together.Therefore, can observe arch might as well, S shape might as well be subjected to the influence of internal stress, have static capacity and almost keep certain characteristics.That is,, but still can suppress electrical characteristic discrete of capacitive coupling type switch although the internal stress of beam is discrete and because environment temperature changes thermal expansion and therefore changes because of manufacturing process produces.
Also have, because make beam 81,82,83 for identical curved shape, so identical mechanical spring characteristic is arranged, for example add potential difference on 81,82 one on beam, both just produce identical displacement, in the 1/2 position contact in gap between the two.For example, make this contact position,, can consider the width W 1 of widening beam 81 as the 1st kind of method as long as improve the rigidity of beam 81 near beam 81 1 sides.For the S ellbeam 81,82 of Δ y=2 μ m, establish under the situation of W1=4 μ m, W2=2 μ m the variation of static capacity between the internal stress of beam and two beams when in Figure 10, using the potential difference V=0 between curve x (drawing the * symbol) the expression beam 81,82.Pass through beam 81 overstrikings like this, the mode of texturing that residual stress causes is different with beam 82, therefore causes static capacity between the two to change increasing.The most extreme form that improves the rigidity of beam 81 be with beam 81 as fixed electrode, but, cause static capacity to change all the more easily at this moment owing to the variation of internal stress.
As other method of two beam contact positions of control, the method for doing the thickness t 1 of beam 81 thicker than the thickness t 2 of beam 82 is for example arranged.If t1=4 μ is m, during t2=2 μ m, the variation of static capacity between internal stress and two beams during with the potential difference V=0 of 81,82 on curve y (drawing the △ symbol) expression beam in Figure 10.Different with the method for widening, clearly, be not to be subjected under the situation of influence of internal stress static capacity almost to be kept certain by thickening getable effect.
Figure 11 shows that a example with switch manufacture method of this structure.Figure 11 is the A-A ' section of Fig. 8 (b), the state of expression is to form dielectric film 91, sacrifice layer 92 on substrate 90, utilize photoetching technique to make the photoresist 86 of wiring figure, utilizes to electroplate between the photoresist 86 of making wiring figure to form beams of metal 81,82,83 again.Inculating crystal layer 87 ground connection of beam 81,83, and for the inculating crystal layer 88 of beam 82, by control switch 89, make it to be set as identical with the anode potential V that is used to electroplate its ground connection before moment T since moment T.93 for providing the anode electrode of anode potential V.Use this electroplating work procedure, beam 81,82,83 is generated as the metal level of equal height before moment T, but stops with the plating generation of the back rest 82 at moment T, thereby can generate beams adjacent but that thickness is different.
Like this, by only a beam itself that constitutes variable capacitor structure being provided with minimum bending, can suppress to become on the slice girder construction characteristic variations such as pull-in voltage problem, that cause because of residual stress or thermal expansion and static capacity.In addition, for example for electrode length L=500 μ m, because the degree of crook size is about several μ m, so the resistive component of this beam itself is also almost identical with straight beam.In addition, beyond girder construction, needn't establish flexing structure etc. again, can not hinder the microminiaturization of element.Also have in making, realize because bending can be drawn by mask, so easy to make of SEMICONDUCTING THIN FILM TECHNOLOGY.
Use the switch of warp architecture, also can be used as on a large scale variable-capacitance element and use instead in miscellaneous equipment.For example, the mechanical resonator of beam as the resonance that utilizes its transverse vibration, in addition the surface of beam is handled, improve surface a adsorptivity of beam to certain gas componant in the atmosphere, then owing to the quality that adhering to of gas makes beam changes, and resonance frequency changes, so can be as gas concentration sensor.At this moment, suppose with the resonator of straight double base beam and adjacent fixed electrode and constitute, then the problem of Cun Zaiing is, when the variation discrete or environment temperature of the beam residual stress that causes owing to manufacturing process causes the beam internal stress to change, resonance frequency changes increasing, but as implementing form 4, the adjacent movable beam of curved shape is arranged, just can relax this change of resonance frequency by use.
Utilize the parameter of the various beam deflection shapes of expression shown in Figure 9, represent the relation of internal stress and 1 rank resonance frequency at Figure 12.Wherein demonstrated the tendency with the same feature of relation of the internal stress of Fig. 9 and pull-in voltage, just can suppress change of resonance frequency by the degree of crook (Δ y) that strengthens S shape.
Also having, in each above embodiment, be that the situation of using three beams of the 1st, the 2nd, the 3rd is described, but the beam that constitutes switch also can make three beams wherein carry out the action of each embodiment with composition more than 4.
(example 5)
The side view of the structure of the switch that Figure 13 relates to for expression the invention process form 5.Figure 13 (a) is illustrated in not alive state on the electrode, and Figure 13 (b) expression adds the state of voltage.Conductive pillar 108 that on end links to each other on the substrate 106 and the conductive pillar 109 that links to each other with the lead-out terminal of output signal with the input terminal of input signal.Between pillar 108,109, hanging the movable electrode 104 of girder construction.Pillar 108 on substrate 106 and 109 centre position are provided with fixed electrode 105, by applying electrostatic force at movable electrode 104 and 105 of fixed electrodes, movable electrode 104 are moved to fixed electrode 105 directions.Form movable electrode 104 on movable body 103, movable body 103 usefulness ICPF (ionic conduction polymer gel mould IonicConducting Polymer gel Film) constitute.ICPF changes because of make internal stress by applied voltage as shown in figure 14, so utilize this character that the spring constant of movable body 103 is changed.Below utilize Figure 15 that switch motion is described.In Figure 15, top part is represented the position of movable electrode 104, and following part is represented the variation of the spring constant of movable electrode 104 along with the time.The neutral position that movable electrode 104 is not added electrostatic force is as zero.Produce electrostatic force at movable electrode 104 and 105 at electrode, movable electrode 104 when electrode 105 side draughts draw, is added control voltage 107 on movable body 103, the spring constant that makes movable body 103 is for minimum.At this moment, because spring force is minimum,, utilize electrostatic force to be attracted at high speed so movable body 103 and movable electrode 104 can not be subjected to the obstruction of spring force.
Then, with movable electrode 104 when electrode 105 draws back, utilize control voltage 107 in advance, movable body 103 is applied voltage, this voltage makes the spring constant of ICPF for maximum, makes spring force become maximum.Then, remove the electrostatic force of 105 of movable electrode 104 and fixed electrodes, the position that utilizes spring force at high speed movable body 103, movable electrode 104 to be restored in regulation like this.
Usually because high-molecular gel is roughly several ms to response time of control signal, therefore for the actuating force of the switch that requires high-speed response time, the flexible of high-molecular gel can not be used for actuating force, but changes at the next spring force that has the sufficient response time to make movable body 103 of the maintained state of switch.When attracting and drawing back, become best value respectively by the spring force that makes movable body 103, thereby can realize high-speed response like this.
The used material of movable body 103 also can adopt the material that can change physical parameter by the control of outside except ICPF, for example be used to high-molecular gel, the piezoelectric of artificial-muscle etc.In addition, as forming movable body, then movable electrode 104 and electrode 105 can be made of one with electric conducting material.
As mentioned above, switch of the present invention, all movable by 3 beams, thus have the effect that can shorten the response time, reduce applied voltage.According to suitable frequency,, make that impedance is best, then also has the beneficial effect that can realize the switch of no frequency characteristic if suitably select the quantity of the beam of use.In addition, by beam being made crooked structure, is had the beneficial effect of the variation that can suppress the switching characteristic that the variation because of internal stress causes.
Claims (25)
1. a switch is characterized in that, comprises
1st, the 2nd, the 3rd beam, they are configured to along transversely arranged, and keep certain intervals each other in orientation, and
The applied voltage device is used for described the the 1st, the 2nd, the 3rd beam respectively applied DC potential so that the the 1st, the 2nd, the 3rd beam added actuating force,
Wherein, described the the 1st, the 2nd, the 3rd beam is movable electrode, and movable along described orientation.
2. switch as claimed in claim 1 is characterized in that,
When switch ON, utilize described applied voltage device between described the 1st beam and described the 2nd beam, to produce actuating force, the 1st beam contacted and electric coupling with the 2nd beam,
When switch OFF, between described the 2nd beam and described the 3rd beam, produce actuating force, make the 1st beam and the 2nd beam separately.
3. switch as claimed in claim 1 is characterized in that,
The arranged spaced of described the the 1st, the 2nd, the 3rd beam becomes can satisfy the interval of regulation insulated degree requirement.
4. switch as claimed in claim 2 is characterized in that,
Described applied voltage device adds the direct voltage of certain hour to described the the 1st, the 2nd, the 3rd beam.
5. switch as claimed in claim 2 is characterized in that,
After described the 1st beam and described the 2nd beam electric coupling, make described the 3rd beam movable.
6. switch as claimed in claim 1 is characterized in that,
By changing the shape of described beam, the spring constant of beam is changed.
7. switch as claimed in claim 1 is characterized in that,
Compare with described the 1st, the 3rd beam, the shape of described the 2nd beam is less.
8. switch as claimed in claim 2 is characterized in that,
Compare with described the 1st, the 3rd beam, the shape of described the 2nd beam is less, under the state of the 1st and the 2nd beam electric coupling, the 3rd beam is added actuating force from the 1st beam, makes the 3rd beam can be to the 1st, the 2nd beam side shifting.
9. switch as claimed in claim 2 is characterized in that,
When described the 1st and the 2nd beam electric coupling, the transposing of the current potential of the current potential of the 1st beam and the 2nd beam, described the 3rd beam do not produced actuating force, make the 3rd beam movable.
10. switch as claimed in claim 2 is characterized in that,
When between described the 2nd beam and the 3rd beam, needing high-isolation, do not make the 3rd beam produce actuating force, do not allow the 3rd beam movable.
11. switch as claimed in claim 2 is characterized in that,
During switch OFF, make described the 2nd beam and the 3rd beam coupling.
12. switch as claimed in claim 1 is characterized in that,
The 1st beam connects antenna end, and the 2nd beam connects input terminal, and the 3rd beam connects the terminal of regulation resistance value.
13. switch as claimed in claim 1 is characterized in that,
Any beam of described the the 1st, the 2nd, the 3rd beam all is with metal.
14. switch as claimed in claim 1 is characterized in that,
Described the the 1st, the 2nd, the 3rd beam arranged in the horizontal direction, and any beam of described the the 1st, the 2nd, the 3rd beam is all movable in the horizontal direction.
15. switch as claimed in claim 1 is characterized in that,
Described the the 1st, the 2nd, the 3rd beam arranged in vertical direction, and any beam of described the the 1st, the 2nd, the 3rd beam is all movable in vertical direction.
16. switch as claimed in claim 12 is characterized in that,
With capacitance arrangement between the 1st beam and the antenna end and be configured between the 2nd beam and the input terminal.
17. switch as claimed in claim 1 is characterized in that,
Switch is moved in a vacuum or in the inert gas.
18. switch as claimed in claim 1 is characterized in that,
In described the the 1st, the 2nd, the 3rd beam, make adjacent two or three beam deflections become identical shape.
19. switch as claimed in claim 18 is characterized in that,
If any deflection of beam of described the the 1st, the 2nd, the 3rd beam is shaped as S shape.
20. switch as claimed in claim 18 is characterized in that,
The thickness of any beam of described the the 1st, the 2nd, the 3rd beam is different with the thickness of adjacent beam.
21. a switch is characterized in that,
By with a plurality of switch in parallel as claimed in claim 1 configurations, thereby obtain desirable impedance.
22. a switch is characterized in that,
By with a plurality of switch in parallel as claimed in claim 1 configurations, thereby obtain desirable capacitance.
23. a switch is characterized in that, with the relative antenna end balanced configuration of the described switch of a plurality of claims 1.
24., it is characterized in that described actuating force is an electrostatic force as any one described switch in the claim 1 to 23.
25., it is characterized in that switching semiconductor technology is made as any one described switch in the claim 1 to 23.
Applications Claiming Priority (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002-217872 | 2002-07-26 | ||
| JP2002217872 | 2002-07-26 | ||
| JP2002217873 | 2002-07-26 | ||
| JP2002-217873 | 2002-07-26 | ||
| JP2002217872 | 2002-07-26 | ||
| JP2002217873 | 2002-07-26 | ||
| JP2003-184204 | 2003-06-27 | ||
| JP2003184204A JP4186727B2 (en) | 2002-07-26 | 2003-06-27 | switch |
| JP2003184204 | 2003-06-27 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031331858A Division CN1276449C (en) | 2002-07-26 | 2003-07-25 | Switch |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1929067A CN1929067A (en) | 2007-03-14 |
| CN1929067B true CN1929067B (en) | 2010-05-26 |
Family
ID=37858973
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006101261339A Expired - Lifetime CN100490044C (en) | 2002-07-26 | 2003-07-25 | Switch |
| CN2006101261343A Expired - Lifetime CN1929067B (en) | 2002-07-26 | 2003-07-25 | Switch |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006101261339A Expired - Lifetime CN100490044C (en) | 2002-07-26 | 2003-07-25 | Switch |
Country Status (1)
| Country | Link |
|---|---|
| CN (2) | CN100490044C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012164725A1 (en) | 2011-06-02 | 2012-12-06 | 富士通株式会社 | Electronic device and method for producing same, and method for driving electronic device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4979149A (en) * | 1986-09-10 | 1990-12-18 | Lgz Landis & Gyr Zug Ag | Non-volatile memory device including a micro-mechanical storage element |
| DE19937811A1 (en) * | 1999-08-11 | 2001-03-22 | Bosch Gmbh Robert | Microrelay for electric circuit, has planar contact elements which contact when diaphragms are deflected thermally and electrostatically |
| US6218911B1 (en) * | 1999-07-13 | 2001-04-17 | Trw Inc. | Planar airbridge RF terminal MEMS switch |
-
2003
- 2003-07-25 CN CNB2006101261339A patent/CN100490044C/en not_active Expired - Lifetime
- 2003-07-25 CN CN2006101261343A patent/CN1929067B/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4979149A (en) * | 1986-09-10 | 1990-12-18 | Lgz Landis & Gyr Zug Ag | Non-volatile memory device including a micro-mechanical storage element |
| US6218911B1 (en) * | 1999-07-13 | 2001-04-17 | Trw Inc. | Planar airbridge RF terminal MEMS switch |
| DE19937811A1 (en) * | 1999-08-11 | 2001-03-22 | Bosch Gmbh Robert | Microrelay for electric circuit, has planar contact elements which contact when diaphragms are deflected thermally and electrostatically |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100490044C (en) | 2009-05-20 |
| CN1929066A (en) | 2007-03-14 |
| CN1929067A (en) | 2007-03-14 |
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