Source: https://patents.google.com/patent/DE60215642T2/en
Timestamp: 2019-12-09 00:55:52
Document Index: 692539172

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DE60215642T2 - Membrane for an electromechanical microswitch and method of making and using same - Google Patents
Membrane for an electromechanical microswitch and method of making and using same
DE60215642T2
DE60215642T2 DE2002615642 DE60215642T DE60215642T2 DE 60215642 T2 DE60215642 T2 DE 60215642T2 DE 2002615642 DE2002615642 DE 2002615642 DE 60215642 T DE60215642 T DE 60215642T DE 60215642 T2 DE60215642 T2 DE 60215642T2
DE2002615642
DE60215642D1 (en
Shea CHEN (nmi), Plano
C. John Garland EHMKE
W. Brandon Dallas PILLANS
Jamie Zhimin Newbury Park YAO
2001-05-25 Priority to US09/866,205 priority Critical patent/US6803534B1/en
2001-05-25 Priority to US866205 priority
2002-05-14 Application filed by Raytheon Co filed Critical Raytheon Co
2002-05-14 Priority to PCT/US2002/015346 priority patent/WO2002096796A2/en
2006-12-07 Publication of DE60215642D1 publication Critical patent/DE60215642D1/en
2007-09-06 Publication of DE60215642T2 publication Critical patent/DE60215642T2/en
These This invention relates generally to switches, and more particularly to electromechanical ones Microswitches that have flexible capacitive diaphragms.
One existing type of switch is a high frequency (HF) electromechanical Microswitch (MEMS). This existing switch has a substrate with two spaced and conductive sockets thereon. A conductive Part is provided on the substrate between the sockets and with a layer of a dielectric material covered. One out an electrically conductive Material manufactured flexible membrane extends between the sockets, so that their middle part above the conductive part on the substrate is. The running between the sockets part of the membrane is in a non-bent state substantially flat. To one of conductive Parts and the membrane is applied an RF signal.
Around to press the switch is a direct current (DC) between the membrane and the conductive part Bias applied, the charges on the membrane and the conductive part which causes them to be electrostatically attracted to each other become. This causes the membrane to bend, leaving itself its middle part moves downwards until it stops with the dielectric Layer over the conductive one Part comes in contact. This is the operating position of the switch. In this operating position This will be due to either the membrane or the conductive part flowing RF signal substantially in its entirety with the other of the both capacitively coupled. To disable the switch is the DC bias is turned off. The inherent elasticity of the membrane then returns the membrane to its original position.
While existing Switches of this type essentially for their intended uses they were not satisfactory in every way. A problem is that the bending of the membrane during the activity required DC bias can be relatively high, for example from 40 to 100 volts. These high biases tend to charge in the form of electrons to introduce into the dielectric layer, and these electrons have a tendency to stay there. The dielectric layer then develops a permanent charge that has the inclination in Interact with the membrane so as to contact the membrane to keep with the dielectric layer, even after the bias voltage was turned off. In other words, the switch will be in his Actuator position locked and can not be disabled. This represents a failure of the Consequently, the buildup of charge in the dielectric layer due to the use of high bias voltages the useful service life of the switch.
A related consideration is that the required minimum bias tends to in terms of temperature changes to fluctuate relatively strongly. The reason is that the substrate and the membrane are made of different materials, the different thermal expansion coefficients (CTE). Thus, with fluctuations in the ambient temperature from a high temperature to a low temperature at certain Temperatures expansion forces exerted on the membrane, and at other temperatures, contraction forces increase she exercised. When expansion forces exerted on the membrane be increased this is for bending the membrane and pulling it down in the operating position required force, which in turn requires a higher preload to use to effect this movement. However, as discussed above the higher one Bias the tilt, the useful operating life of the device to diminish. To a reasonable To reach lifetime have been existing switches of this type for the Specified within a limited temperature range, the smaller than one for most commercial applications is targeted and the much smaller than the one for military equipment required area is.
Another consideration with these existing switches is that while the bias is used to flex the diaphragm to its actuated position, no external force is applied to the diaphragm when the switch is deactivated. Instead, the inherent elasticity of the membrane itself must be sufficient to return the membrane to its original position. As discussed above, an accumulation of charges in the dielectric layer can cause the tendency to electrostatically attract the membrane and thus resist the movement of the membrane back to its deactivated position. One way to respond to this problem is to increase the elastic restoring force within the diaphragm itself, but this has the disadvantage that a larger force is required to bend the diaphragm to its actuated position, which in turn means a higher preload to operate the switch is required. However, as discussed above, higher biases increase the rate at which residual charges within the remove the lektrischen layer, which in turn reduces the useful life of the switch.
A further consideration is that existing switches have relatively thin membranes around the membrane to give sufficient flexibility, in response to the Preload in their operating position to move. The relatively small cross-sectional area of these existing membranes kidnapped however, to a membrane resistance of approximately 0.5 ohms to 1.0 ohms, which is higher is ideally sought and what limits the amount of electricity that in practice can flow through the membrane, bringing the amount of power limited that the switch will handle can.
A further consideration in terms of performance, the power handling capacity of this limited to existing switches, is that a big one HF current can generate a magnetic field that has the tendency the membrane in the operating position even after the DC bias has been turned off. As noted above, it is possible the elastic restoring force increase, which pushes the membrane upwards, which, however, in turn Requirement to increase the bias for operating the switch, and a reduction of the higher Preload has the undesirable Effect of reducing the operating life of the switch.
One An example of an electromechanical microswitch is disclosed in the US patent No. 6,100,477, with a membrane lying flat on a dielectric and the bottom electrode is pulled.
Out the above statements It can be seen that there is a need for a method and a device for the manufacture and operation of a switch of the type comprising a flexible membrane has emerged, so that the switch over a wide Temperature range with a much lower response voltage as existing switch reliable can be operated. According to a form The present invention relates to a method and an apparatus created to meet this need, which is a switch use a base section, an electrically conductive part, which is carried by the base portion, and an electrically conductive membrane contains their first and second end are at offending sites support the base section, which membrane has an electrically conductive part between is arranged at their ends. The method and apparatus include: Providing an elastic structure between the first and the second end of the membrane, which is capable of a longitudinal direction the membrane to yield flexible, so as to have an effective length of the Increase membrane; and responding to a between the conductive part and the conductive part applied stress by elastic bending of the membrane, so that The membrane from a first position in which the membrane is not is bent and the conductive part from the conductive one Part is spaced, moved to a second position in which the Membrane is bent and the conductive part of the conductive part is immediately adjacent, wherein the elastic structure expands, when the diaphragm from the first position to the second position is moved.
A different form of the present invention relates to the manufacture of a switch and includes: forming an electric conductive Part on a base section; Forming a spacer layer over the conductive Part that has a top surface with a part that has either a groove or a bridge in relation on the rest of the upper surface forms; Forming a membrane layer over the upper surface, the has a first and a second end, with spaced parts of the base portion are engaged, which at opposite Sides of the conductive Part are arranged, and an electrically conductive part between the first and second ends; and removing the spacer layer, so as to leave the membrane layer supported on its ends, wherein the electrically conductive Part about the conductive one Part is spaced.
The The present invention will become apparent from the following detailed description. read in conjunction with the accompanying drawings, better understood.
1 Fig. 3 is a schematic partial side sectional view of an apparatus incorporating an electromechanical microswitch embodying the present invention;
2 is a schematic partial plan view of the device 1 and also schematically shows a control circuit which effects the operation of the switch;
3 is a schematic partial side sectional view similar 1 however, shows a different operating position of a diaphragm of the switch;
4 is a schematic partial sectional view similar 1 and 3 however, shows another operating position of the membrane of the switch;
5 is a schematic lateral part cut view of the switch off 1 at a point in time during the manufacturing process of the switch;
6 is a schematic partial side sectional view similar 1 however, as a background to the present invention shows a different device incorporating a switch;
7 is a schematic partial side sectional view showing the device 6 at a time during manufacture of the switch;
8th is a schematic partial side sectional view similar 6 however, as background for the present invention shows another device including a switch;
9 Fig. 12 is a schematic diagram showing as background of the present invention several different types of membranes used in electromechanical microswitches;
10 - 17 are graphs that graph different different properties of one or more of the 9 represent membranes shown; and
18 and 19 are each a schematic side view of a part of one of the membranes 9 showing how the membrane responds to temperature fluctuations.
1 is a schematic partial side sectional view of a device, the electromechanical micro-switch (MEMS) 10 which embodies the present invention. 2 is a schematic partial plan view of the device 1 and shows the switch 10 ,
The desk 10 contains a silicon semiconductor substrate 13 , which has an oxide layer on its upper side 14 which, in the illustrated embodiment, is silica, but could alternatively be another suitable material, such as gallium arsenide or a suitable alumina. As 1 shows are two sockets 17 and 18 at spaced locations on the oxide layer 14 each made of a conductive material such as gold. The substrate 13 , the oxide layer 14 and the pedestals 17 and 18 can as a base section of the switch 10 be designated.
An electrically conductive electrode 23 is on the upper surface of the oxide layer 14 between the sockets 17 and 18 intended. As 2 shows is the electrode 22 an oblong strip. The electrode 22 serves as a transmission line. The one between the sockets 17 and 18 located portion of the electrode is covered with a dielectric layer 23 covered, which is made of silicon nitride.
A conductive membrane 31 extends between the upper ends of the pedestals 17 and 18 , The membrane 31 is made from an aluminum alloy known in the art which contains approximately 99% by weight of aluminum, with much or all of the remainder being silicon or titanium. However, other suitable materials could alternatively be for the membrane 31 be used. The membrane 31 has ends 32 and 33 , each on the top section of each socket 17 and 18 are found. The membrane 31 has between the ends 32 and 33 a middle part 36 that is directly above the electrode 22 and the dielectric layer 23 is arranged. The membrane 31 has her ends 32 and 33 adjacent respective outer parts 37 and 38 , The middle part 36 and the outer parts 37 and 38 are approximately in one plane.
The membrane 31 has an expansion section 41 between the middle part 31 and the outer part 37 and a similar expansion section 42 between the middle part 36 and the outer part 38 , The expansion sections 41 and 42 are each approximately U-shaped. In detail, the expansion section comprises 41 spaced vertical parts 46 and 47 and a horizontal part 48 placed between the lower ends of the vertical parts 46 and 47 runs. In the in 1 shown operating position is the horizontal part 48 approximately parallel to the middle part 36 and the outer part 37 and the vertical parts 46 and 47 are each approximately perpendicular to the horizontal part 48 , the middle part 46 and the outer part 37 , The expansion section 42 is similar and includes vertical parts 51 and 52 and a horizontal part 53 ,
The parts 48 and 53 have the same length and parts 46 - 47 and 51 - 52 all have the same height. The outer parts 37 and 38 have the same length. In 1 have the parts 37 and 38 each the same length as the parts 48 and 53 ,
During operation, a radio frequency (RF) signal having a frequency in the range of approximately 300 MHz to 90 GHz passes through either the diaphragm 31 or the electrode 22 which serves as a transmission line. More specifically, the RF signal from the socket 17 through the membrane 31 to the pedestal 18 to run. Alternatively, like 2 shows the RF signal through the electrode 22 from the lower part of the figure to the upper part of the figure. The operation of the switch 10 is performed under the control of a DC bias voltage, which is applied between the membrane 31 and the electrode 22 is applied by a control circuit of a known type and schematically in 2 with broken lines with 61 is specified. This bias voltage is also referred to as a response voltage (V p ).
When the bias voltage to the switch 10 is not applied, the membrane has the in 1 shown position. As discussed above, an RF signal passes through either the membrane 31 or the electrode 22 , To simplify the following explanation, it is assumed that this RF signal passes through the electrode 22 running. If the membrane 31 in the position off 1 is that flows through the electrode 22 ongoing RF signal through the switch 10 and then continues through the electrode 22 without any appreciable coupling of this RF signal from the electrode 22 over the membrane 31 is present.
To the switch 10 Pressing will cause a DC bias from the control circuit 61 between the electrode 22 and the membrane 31 created. This voltage generates charges on the membrane 31 and on the electrode 22 that cause the middle section 36 the membrane 31 by an electrostatic force to the electrode 22 pulled out. This attraction causes the membrane 31 to bend down, leaving her middle part 36 to the electrode 22 moved. As this occurs, the vertical parts tilt 46 and 47 of the expansion section 41 each slightly in relation to the horizontal part 48 so that their upper ends move away from each other. The vertical parts 51 and 52 of the expansion section 42 perform a similar tilting movement. This leads to a slight increase in the effective length of the two expansion sections 41 and 42 , which in turn leads to a slight increase in the total effective length of the membrane 31 leads. The membrane 31 This makes it easier to move downwards than would be the case if the diaphragm were 31 the expansion sections 41 and 42 would not have.
When the membrane 31 Bends down, she reaches the in 3 shown position in which at least a part of each horizontal part 48 and 43 with the oxide layer 41 engages. In this position is the middle part 36 the membrane 31 still at a small distance above the dielectric layer 23 spaced apart the electrode 22 covered. Another downward movement of the middle section 36 the membrane 31 requires the bending of the middle part 36 itself. This additional deflection requires a higher attractive force between the middle part 36 and the electrode 22 than to effect the initial downward movement of the midsection 36 was required. On the other hand, the middle part 36 and the electrode 22 are physically closer now than they are in the in 1 were shown, the electrostatic attraction between them is higher by itself, than in the operating position 1 the case was. Thus, the additional force that results in causing the further downward movement of the central part occurs 36 from the operating position 3 in the operating position 4 is required, without it being necessary to increase the DC bias voltage between the membrane 31 and the electrode 22 is created.
More specifically, the middle section bends 36 the membrane from the in 3 shown position until its center on the top of the dielectric layer 23 hits, like 4 shows. This is the operating position of the switch 10 , In this position is the capacitive coupling between the electrode 22 and the middle part in the membrane 36 approximately one hundred times greater than when the membrane is in the deactivated position shown in FIG. Consequently, this will be through the electrode 22 current RF signal substantially in its entirety from the electrode 22 over into the membrane 31 coupled and has a tendency to components coming from the middle part 36 away in opposite directions to the respective sockets 17 and 18 to run. Alternatively, if the RF signal from the socket 17 to the pedestal 18 through the membrane 31 would run, the RF signal would be essentially in its entirety from the central part 36 to the electrode 22 be coupled and would tend to from the switch 10 in opposite directions through the electrode 22 to run.
Once the membrane 31 in the 4 has reached shown actuating position, the control circuit 61 optionally, reduce the DC bias to a standby or hold value that is less than the threshold voltage used to initiate the downward movement of the diaphragm 31 out of the position 1 is necessary, but sufficient to the membrane 31 in the operating position 4 once it has reached this actuation position.
To the switch 10 to disable, the control circuit turns off 61 the DC bias decreases between the diaphragm 31 and the electrode 22 is created. The elasticity of the curved middle part 36 results in connection with the engagement of the adjacent expansion sections 41 and 42 with the oxide layer 14 to a relatively strong restoring force, the upward movement of the middle part 36 away from the dielectric layer 23 and the conductive part 22 triggers. Once the upward movement is triggered, the membrane moves 31 continue and go through the position 3 while due to the elasticity within the membrane 31 into the posi tion 1 returns. At the same time, the expansion sections are drawn 41 and 42 each elastic to their original shape and length together.
5 is a schematic partial side sectional view of the switch 10 out 1 , which set a time during the manufacture of the switch 10 according to a process embodying the present invention. In more detail, the preparation begins with the silicon substrate 13 , whereupon the oxide layer 14 by depositing silicon dioxide on the substrate 13 is formed. Then the electrode 22 on the oxide layer 14 formed, for example, in that a gold layer is deposited and then a pattern etching is performed.
Subsequently, the dielectric layer 23 is formed by depositing a silicon nitride layer, followed by pattern etching. A spacer layer 76 then passes over the oxide layer 14 and the dielectric layer 23 educated. The spacer layer 76 is a photoresist material of a type known to those of ordinary skill in the art. The photoresist layer is then patterned and etched one or more times to form spaced, transverse grooves 77 and 78 in an upper surface of the spacer layer 76 to form and so the vertical side surfaces 81 and 82 to form the places adjacent to which the pedestals 17 and 18 be formed. The grooves 77 and 78 each have an approximately rectangular cross-section.
Subsequently, the sockets 17 and 18 is formed by depositing a gold layer and then performing a pattern etch to remove unwanted material, such as the sockets alone 17 - 18 to leave. Then, a layer of the above-mentioned aluminum alloy is coated over the spacer layer 76 , the electrodes 17 - 18 and the oxide layer 14 deposited and then patterned and etched to the membrane 31 to build. At this point, the construction has the in 5 shown configuration.
Subsequently, an etching process called a membrane release etch is performed around the spacer layer 76 completely remove. The membrane release etch can be, for example, a plasma etch of a known type, or any other suitable etch that attacks the material of the photoresist, which is the spacer layer 76 forms. This etching leaves the membrane 31 at their ends 32 and 33 on the pedestals 17 - 18 suspended. This is the completed configuration of the switch 10 , in the 1 is shown.
6 is a schematic partial side sectional view similar 1 However, as background of the invention shows one of the switch 10 out 1 different switches 110 , Here is the switch 110 generally the switch 10 out 1 similar, except that the switch 110 a membrane 131 that's different from the membrane 31 of the switch 10 differentiate. The rest of construction in 6 is denoted by the same reference numerals that are also used in 1 be used.
The membrane 131 out 6 is made of the same material as the membrane 31 out 1 produced. It contains ends 132 and 133 , each one on each of the pedestals 17 and 18 are firmly supported. The membrane 131 has a middle part 136 and two outer parts 137 and 138 , each one of the ends 132 - 133 are adjacent. The membrane 131 has a substantially U-shaped expansion section 141 between the middle part 136 and the outer part 137 and another substantially U-shaped expansion section 142 between the middle part 136 and the outer part 138 , The middle part 136 and the outer parts 137 and 138 are approximately coplanar with each other when the membrane 131 not bent. A difference between the membrane 131 out 6 and the membrane 31 out 1 lies in the fact that the expansion sections 41 and 42 the membrane 31 in terms of their midsection 36 project downwards, whereas the expansion sections 141 and 142 the membrane 131 in terms of their midsection 136 to project upwards.
More specifically, the expansion section comprises 141 two spaced vertical parts 146 and 147 , each from the middle part 136 or the outer part 137 perpendicular to these run upwards. The expansion section 141 further comprises a horizontal part 148 which is between the upper ends of the vertical parts 146 and 147 perpendicular to these runs. Similarly, the expansion section comprises 142 vertical parts 151 and 152 , each from the middle part 136 or the outer part 138 perpendicular to these upwards, and includes a horizontal part 153 which is between the upper ends of the vertical parts 151 - 152 perpendicular to these runs.
The operation of the switch 110 out 6 is generally similar to the operation of the switch 10 out 1 , with the exception of the points discussed below. More specifically, it should be obvious that when the membrane is 131 during operation of the switch 110 Bend down, the expansion sections 141 and 142 not on the oxide layer 14 incident. Thus, the membrane 131 simply a generally progressive bending movement from within the 6 shown position in a position in which the center of the middle part 136 on top of the dielectric layer 23 rests. Even if those at the switch 110 applied DC bias is turned off to disable the switch, the restoring force, which is the upward movement of the diaphragm 131 back to the in 6 shown position, by inherent elasticity in the entire section of the membrane 131 causes the between the electrodes 17 - 18 is arranged.
7 is a schematic partial side sectional view of the switch 110 , which set a time during the manufacture of the switch 110 according to a process embodying the present invention. This will be the substrate 13 , the oxide layer 14 , the electrode 22 and the dielectric layer 23 all in a similar manner as above with reference to 5 formed described. Then a spacer layer becomes 176 formed from a known photoresist or polyimide material and patterned and etched in a suitable shape, including the formation of the side surfaces 181 - 182 , Then, another layer of the same or an equivalent material on the spacer layer 176 deposited and patterned and etched to spaced and parallel ridges or spacers 177 and 178 to build.
Then the membrane becomes 131 prepared in a manner similar to that described above with respect to the formation of in 5 shown membrane 31 is similar. This leads to the in 7 shown construction. Then, a plasma etch or other suitable technique is used to remove the photoresist material that serves as the spacer layer 176 and the spacers 177 and 178 serves, causing the switch 110 in his final, in 6 configuration remains.
8th is a schematic partial side sectional view similar 6 However, as background of the invention shows a switch 210 that from the switch 110 out 6 is different. The main difference between the switch 210 out 8th and the switch 110 out 6 lies in the fact that the switch 210 a membrane 231 that's different from the membrane 131 out 6 different. The remaining parts of the switch 210 are the corresponding parts of the switch 10 out 1 and the switch 110 out 6 and are denoted by the same reference numerals.
The membrane 231 out 8th has ends 232 and 233 , each on a pedestal 17 - 18 are firmly supported. Furthermore, the membrane has 231 a middle part 236 , where expansion sections 241 and 242 lie on opposite sides of the same. The main difference between tween the membrane 231 out 8th and the membrane 131 out 6 lies in the fact that the expansion sections 141 and 142 the membrane 131 have a shape that approximately represents a square wave or a rectangle, whereas the expansion sections 241 - 242 the membrane 231 each have a shape representing a period of a sine wave from a negative vertex of the sine wave to the next negative vertex. The expansion sections 241 - 242 each protrude in relation to the middle part 236 upwards. The operation of the switch 210 out 8th is generally similar to the operation of the switch 110 out 6 and it is therefore not considered necessary to give a separate detailed explanation as the switch 210 is working.
9 is a diagram showing as a background for the invention six schematic membranes AF, each extending between electrodes, which schematically with 301 and 302 are designated. This is not a single switch with six diaphragms, but six diaphragms taken from six different switches and shown together for comparison purposes. It can be seen that the membrane B is similar to the membrane 231 out 8th and the membrane F is similar to the membrane 131 out 6 is. Membranes D and E are variations of the membrane 31 out 6 , The membrane A off 9 is a membrane of an existing type of the prior art, which in 9 is included as a reference against which the other membranes are evaluated. The centers of the membranes AF are at positions that are the broken line 304 correspond.
For purposes of the following discussion, reference will be made to the membranes 9 However, it should be understood that these dimensions are intended for purposes of illustration only and are not intended to suggest that the present invention is in any way limited to these particular dimensions. In this regard, it is believed that the distance 306 between the electrodes 301 - 302 300 to 320 microns. Further, it is assumed that the membranes AF each have a thickness of 0.3 microns. It is assumed that the switches in which the diaphragms AF are installed are identical except for the diaphragms and that each of these switches has a dielectric layer with a thickness of approximately 0.1 microns and a gap between the diaphragm and the dielectric of FIG Mikron has when the switch is off.
Focusing on the diaphragm B, the spaced apart expansion sections comprise a single period of a sine wave at each end, which is one period 308 of approximately 15 microns and an amplitude 309 of approximately 3 microns. The expansion sections of the membrane B are each one of the pedestals 301 and 302 tight positioned next to it.
Turning to membrane C, this membrane is generally similar to membrane B, except that the expansion sections at each end comprise five periods of a sine wave rather than just one period, these periods being together at a distance 313 which is approximately 100 microns. These sine waves each have the same amplitude as the waves in the membrane B, in other words an amplitude of 3 microns.
The membranes D, E and F are each a variation of the membrane 131 out 6 wherein the ratio of the length of the expansion portion to the adjacent outer portion is different. The outer parts of the membrane D each have a length of approximately 10 microns and the expansion sections each have a length of approximately 90 microns. The outer parts of the membrane E each have a length of approximately 30 microns and their expansion sections each have a length of approximately 70 microns. The outer parts of the membrane F each have a length of approximately 50 microns and their expansion sections each have a length of approximately 50 microns.
10 Figure 11 is a graph showing the variation in the threshold voltage required to actuate the switch with the variation in the number of waves in the expansion sections of the membrane. This is the point 320 the membrane A from 9 which has no expansion sections or waves. The point 321 turns off the membrane B. 9 which has a sine wave in each expansion section. The points 322 - 324 Representative variations of the membrane B, which in 9 are not shown separately and each have two, three and four sine waves in each expansion section. The point 325 in 10 Turns the membrane C off 9 which has five sine waves in each expansion section.
Based on a comparison of the points 320 and 321 It will be appreciated that the provision of spaced apart expansion sections with a sine wave provides a substantial reduction of approximately 70% of the operating voltage required to actuate the switch. Like the dots 322 - 325 show that adding additional sine waves to the expansion sections gives even better performance, but with a diminishing, low effect.
11 is another diagram that is specific to the membrane B 9 refers to and shows how the response voltage in response to the change in wavelength or period or in other words the change in the distance 308 in 9 changed. It can be seen that there is a significant reduction in the response voltage when the wavelength is less than about ten times the amplitude, but has a limited additional advantage if the wavelength is increased beyond ten times the amplitude.
12 is a diagram that also refers to the B membrane 9 refers and shows how the required response voltage with a different amplitude 309 changed. It can be seen that the response voltage is significantly reduced as the amplitude is increased until the amplitude is approximately 20% to 25% of the wavelength or period 308 is. Additional increases in amplitude provide only a limited added benefit.
13 is a diagram that shows six curves, each one of the diaphragms AF out 9 correspond. In fact, these curves each show the extent to which the associated membrane tends to sag in response to temperature variations. It can be seen that at higher temperatures the membranes DF tend to show less sag than the membranes AC.
14 and 15 are related diagrams, each showing six curves representing the six AF membranes 9 match, where 15 a view of the lower section of 14 with an enlarged vertical scale. The diagrams of 14 and 15 each show how the operating voltage required for actuation fluctuates in connection with the temperature. It can be seen that the membranes CF can be operated over the entire specified temperature range with a response voltage which is significantly lower than that required for the membranes A and B.
16 is a diagram that shows six lines, each one of the six membranes AF in 9 correspond. 16 Figure 12 shows the stress that occurs in each membrane at different temperatures when the membrane is in its deactivated position. It can be seen that the membranes CF all show significantly less stress than the membranes A and B.
17 is a diagram that shows six lines, each one of the six membranes AF out 9 correspond. 17 Figure 12 shows how the tension within each membrane varies with temperature when the membrane is in its actuated position or in other words in its bent position. It can be seen that the greatest tension occurs at low temperatures the membrane C experiences significantly less internal stress than the membranes DF at low temperatures and that all the membranes CF show less stress than the two membranes A and B.
18 and 19 are similar schematic views that make up the left half of the membrane F. 9 show at selected temperatures. 18 and 19 is based in each case on the assumption that the membrane is prepared in such a way that it has no thermal deformation at a temperature of 80 ° C. 18 shows the type of deformation that the membrane undergoes when heated from 80 ° C to 100 ° C. 19 shows the deformation that the membrane undergoes when cooled from 80 ° C to -40 ° C. On the right side of 19 It can be seen that the center portion of the membrane does not undergo significant deformation or moves up or down when the ambient temperature is changed from -40 ° C to + 80 ° C over the temperature range of 120 ° C. In contrast, on the right side of 18 to see that the central part of the membrane undergoes a certain deformation and moves downwards over a small distance when the membrane has been heated to 100 ° C.
Actually show 18 and 19 the manner in which the membrane is deformed as a result of the different thermal expansion coefficients (CTE) of the membrane and the associated substrate. The tilting of the vertical portions of the membrane compensates for the temperature range of 120 ° C for the CTE discrepancy between the membrane and the substrate, while avoiding deformation of the center portion of the membrane.
The The present invention offers a number of technical advantages. Such an advantage results from the fact that in a membrane elastic structure is provided, such as at play spaced Expansion sections that are capable of moving longitudinally the membrane to yield flexible, so as to have an effective length of the Increase membrane and thereby the elastic bending of the membrane between positions to facilitate that operated and the unactuated Condition of a switch correspond. This reduces the for the operation of the Switch's required response voltage.
One Further technical advantage results from the configuration of Expansion sections, so they have a first and a second Part contain, approximate vertical and parallel, as well as a third part, which is between the first and the second part extends approximately perpendicular to these. The first and the second part can tilt to some extent, so either the expansion or the contraction of the effective Length of Membrane to facilitate a discrepancy of the CTEs of the membrane and the substrate. By balancing the discrepancy of the CTEs the extent is reduced, in which the response over the temperature fluctuates. The switch can thus via a wider temperature range with a lower response voltage to work as existing switches.
In In one form of the present invention, the expansion sections jump with respect to the remainder of the membrane, down to the base section out in front. As a result, these expansion sections meet on the Base section on before the middle part of the membrane on the dielectric Layer over the electrode hits. The middle part then bends until he rests on the dielectric layer. An advantage of this approach is that when the DC bias is turned off by one the activation of the switch to a considerable upward force is exerted on the central part of the membrane, so its moving away from the dielectric layer and the Lead in electrode. This significantly reduces the probability that residual charges in the dielectric layer are electrostatic Create attraction that can hold the membrane in its actuated position, even after the DC bias has been turned off. One with this Arrangement connected advantage is that the increased restoring force is achieved without an increased response voltage is needed, around the diaphragm from its deactivated position to the actuation position to move.
One Another advantage is that the provision of expansion sections it allows the membrane to be made slightly thicker than in an earlier existing one Membrane that has no expansion sections would be the case. The thicker membrane lowers the effective resistance of the membrane, what in turn allows the operation of the switch at a higher power level.
Device comprising a switch ( 10 ), the switch comprising: a base section ( 13 . 14 . 17 . 18 ); an electrically conductive part ( 22 ) carried by the base portion; an electrically conductive membrane ( 31 ), whose first ( 32 ) and second end ( 33 ) at spaced first and second locations on the base portion ( 13 . 14 . 17 . 18 ), whereby the membrane ( 31 ) a middle part ( 36 ), which is between her first ( 32 ) and second ( 33 ) End, the membrane ( 31 ) a first ( 41 ) and a second one ( 42 ) Section has, on opposite sides of the middle part ( 36 ), the first ( 41 ) and the second section ( 42 ) each transverse to the membrane ( 31 ) and have an approximately U-shaped profile, wherein the conductive part ( 22 ) between the first ( 41 ) and the second ( 42 ) Section is positioned, wherein the membrane ( 31 ) is able to flex elastically so that the membrane ( 31 ) from a first position in which the membrane ( 31 ) is substantially not bent and the middle part ( 36 ) of the conductive part ( 22 ), in a second position, in which the membrane ( 31 ) and the middle part ( 36 ) the conductive part ( 22 ) is immediately adjacent, can move; wherein the first and second portions engage the base portion before the middle portion (FIG. 36 ) the conductive part ( 22 ) immediately adjacent position when the membrane ( 31 ) moves from the first position to the second position, and wherein the middle part ( 36 ), causing a movement of the middle part ( 36 ) into the conductive part ( 22 ) Immediately adjacent position is effected.
Device according to claim 1, comprising a dielectric layer ( 23 ) above the conductive part ( 22 ), wherein the middle part ( 36 ) of the membrane ( 31 ) on one side of the dielectric layer ( 23 ) engaging the conductive part ( 22 ) when the diaphragm is in the second position.
Apparatus according to claim 1 or claim 2, wherein the first ( 41 ) and the second section ( 42 ) are flexible and able to measure their size in a longitudinal direction of the membrane ( 31 ) in such a way that an effective length of the membrane ( 31 ) changed.
Device according to one of the preceding claims, in which, when the membrane is in the first position, the U-shaped profile of the first ( 41 ) and the second ( 42 ) Has approximately the shape of a half-period of a sine wave.
Device according to one of claims 1 to 3, in which, when the membrane is in the first position, the U-shaped profile of the first ( 41 ) and the second ( 42 ) Section each a spaced first ( 46 ) and second ( 47 ) Has part which are approximately straight and approximately parallel to each other, wherein the U-shaped profile further comprises a third part ( 48 ), which is approximately straight and between the ends of the first ( 46 ) and the second ( 47 ) Partes approximately perpendicular to these runs
Apparatus according to claim 5, wherein the first ( 46 ) and the second ( 47 ) Part of each of the first ( 41 ) and the second section ( 42 ) in response to exerting either a longitudinal force of contraction or a longitudinal expansion force on the diaphragm ( 31 ) relative to its third part ( 48 ) incline.
Apparatus according to claim 5, wherein the first ( 46 ) and the second ( 47 ) Part of each of the first ( 41 ) and the second ( 42 ) Section of opposite ends of its third part ( 48 ) extend in a direction toward the base portion.
Apparatus according to claim 1, wherein the U-shaped profile comprises several periods of a sine wave.
A device according to any one of the preceding claims, wherein the diaphragm has outer parts respectively extending outwardly from the respective first and second sections on a side thereof opposite the central part, the central part and the outer parts being approximately in a plane when the Membrane ( 31 ) is in the first position.
Device according to one of the preceding claims, wherein which is the U-shaped Profile approximated to a rectangle is.
Device according to claim 1, wherein the base section is a substrate ( 13 ), the two conductive pedestals ( 17 . 18 ) projecting therefrom from the first and second spaced locations, the conductive portion (12) 22 ) between the sockets ( 17 . 18 ) and the first ( 32 ) and the second ( 33 ) End of the membrane ( 31 ) each from a pedestal ( 17 . 18 ) are worn.
Device according to claim 2, comprising a circuit ( 61 ) which is operable to move between the electrically conductive part ( 22 ) and the membrane ( 31 ) applies a first voltage which is a movement of the membrane ( 31 ) from the first position to the second position; the circuit ( 61 ) is operable so that it then between the electrically conductive part ( 22 ) and the membrane ( 31 ) applies a second voltage which is smaller than the first voltage and which is sufficient to allow the membrane ( 31 ) in their second position.
Method of switching by use of a switch ( 10 ), which has a base section ( 13 . 14 . 17 . 18 ), an electrically conductive part carried on the base portion (US Pat. 22 ) and an electrically conductive membrane ( 31 ), which is a first ( 32 ) and a second one ( 33 ) End, which at spaced locations on the base section ( 13 . 14 . 17 . 18 ) and one between their first ( 32 ) and second ( 33 ) End arranged middle part ( 36 ) Has, containing the steps: configuring the membrane ( 31 ) in such a way that they on opposite sides of the middle part ( 36 ) arranged a first ( 41 ) and a second section ( 42 ), the first ( 41 ) and the second section ( 42 ) in each case in the transverse direction to the membrane ( 31 ) and have an approximately U-shaped profile, wherein the conductive part ( 22 ) between the first ( 41 ) and the second ( 42 ) Section is positioned; Applying a voltage between the conductive part ( 22 ) and the middle part ( 36 ), wherein the tension is operable such that: the membrane ( 31 ) is bent elastically, so that the membrane ( 31 ), in response to the strain, from a first position in which the membrane ( 31 ) is not bent and the middle part ( 36 ) of the conductive part ( 22 ) is moved to a second position, in which the membrane ( 31 ) and the middle part ( 36 ) the conductive part ( 22 ) is immediately adjacent; and the first and second portions are caused to engage the base portion before the middle portion (FIG. 36 ) the position in the immediate vicinity of the conductive part ( 22 ) is reached when the membrane ( 31 ) moves from the first position to the second position.
The method of claim 13 including the step of configuring the first ( 41 ) and the second ( 42 ) Portion each having a U-shaped profile in the form of a half period of a sine wave.
The method of claim 13 including the step of configuring the first ( 41 ) and the second ( 42 ) Section each in such a way that when the membrane ( 31 ) in the first position, its U-shaped profile spaced a first ( 46 ) and a second ( 47 ) Contains part which are approximately straight and approximately parallel to each other, wherein the U-shaped profile further comprises a third part ( 48 ), which is approximately straight and between the ends of the first ( 46 ) and the second ( 47 ) Partes approximately perpendicular to these runs.
The method of claim 15 including the step of causing the first ( 46 ) and the second ( 47 ) Part of each of the first ( 41 ) and the second ( 42 ) Section in response to the application of either a longitudinal expansion force or a longitudinal contractive force to the diaphragm (FIG. 31 ) relative to its third part ( 48 ) incline.
Method according to claim 13, comprising the steps of: bending a middle part of the membrane ( 31 ), who between her first ( 41 ) and second ( 42 ) Section is arranged to move the middle part ( 36 ) in the position in the immediate vicinity of the conductive part ( 22 ) to effect.
The method of claim 13, comprising the step: Configure the switch in such a way that it has one over the conductive part arranged dielectric layer, wherein the middle part of the Membrane engages one side of the dielectric layer, the conductive one Part is opposite when the diaphragm in the second position is.
A method according to claim 13, comprising the steps of: causing the application of the applied voltage between the electrically conductive part (16). 22 ) and the middle part ( 36 ) by applying a first voltage between them which limits the movement of the membrane ( 31 ) from the first position to the second position; and then applying a second voltage between them which is lower than the first voltage and which is sufficient to cause the membrane ( 31 ) in their second position.
Method for producing a switch, comprising the steps: forming an electrically conductive part ( 22 on a base section; Forming a spacer layer over the conductive part ( 22 ) having a top surface with a portion forming a pair of grooves located outside each end of the conductive part (10). 22 ) are spaced relative to a remainder of the upper surface, which conductive portion ( 22 ) is positioned between the pair of grooves; Forming an electrically conductive membrane layer ( 31 ) above the upper surface, which is a first ( 32 ) and a second end ( 33 ), which with spaced portions of the base portion, on opposite sides of the conductive part ( 22 ) are in engagement, which membrane layer ( 31 ) a middle part ( 36 ) between the first and second ends, which membrane layer ( 31 ) a first ( 41 ) and a second ( 42 ) Has sections which are located within the groove pair on opposite sides of the central part ( 36 ), the first ( 41 ) and the second ( 42 ) Section in each case in the transverse direction to the membrane ( 31 ) and have an approximately U-shaped profile; and removing the spacer layer so as to seal the membrane layer ( 31 ) to be supported on their ends, the middle part ( 36 ) over the conductive part ( 23 ), which membrane layer ( 31 ) is operable to bend to a first position where the first ( 41 ) and the second ( 42 ) Engage the base portion before the center portion engages the conductive portion (FIG. 42 ) comes into engagement.
The method of claim 20, wherein the step forming the spacer layer by forming a first part the spacer layer over the conductive one Part and the subsequent Forming second parts of the spacer layer, which are the pair of grooves included on their first part.
The method of claim 20, including the step of forming the base portion by performing the steps of: providing a substrate ( 13 ); Forming an oxide layer ( 14 ) above the substrate ( 13 ); Forming two spaced conductive sockets ( 17 . 18 ) at spaced locations on the oxide layer ( 14 ), which sockets ( 17 . 18 ) are the spaced portions of the base portion that the first ( 32 ) and the second ( 33 ) End of the membrane layer ( 31 ) wear; and performing the step of forming the conductive part ( 22 ) by the conductive part ( 23 ) in one place between the pedestals ( 17 . 18 ) is formed.
DE2002615642 2001-05-25 2002-05-14 Membrane for an electromechanical microswitch and method of making and using same Active DE60215642T2 (en)
US09/866,205 US6803534B1 (en) 2001-05-25 2001-05-25 Membrane for micro-electro-mechanical switch, and methods of making and using it
US866205 2001-05-25
PCT/US2002/015346 WO2002096796A2 (en) 2001-05-25 2002-05-14 Membrane for micro-electro-mechanical switch, and methods of making and using it
DE60215642D1 DE60215642D1 (en) 2006-12-07
DE60215642T2 true DE60215642T2 (en) 2007-09-06
ID=25347146
DE2002615642 Active DE60215642T2 (en) 2001-05-25 2002-05-14 Membrane for an electromechanical microswitch and method of making and using same
US (1) US6803534B1 (en)
EP (1) EP1395516B1 (en)
AT (1) AT343544T (en)
AU (1) AU2002305598A1 (en)
DE (1) DE60215642T2 (en)
TW (1) TW582043B (en)
WO (1) WO2002096796A2 (en)
DE102007035633B4 (en) 2007-07-28 2012-10-04 Protron Mikrotechnik Gmbh Process for producing micromechanical structures and micromechanical structure
EP2249365A1 (en) 2009-05-08 2010-11-10 Nxp B.V. RF MEMS switch with a grating as middle electrode
WO2011041676A2 (en) * 2009-10-01 2011-04-07 Cavendish Kinetics, Inc. Micromechanical digital capacitor with improved rf hot switching performance and reliability
CN103552978B (en) * 2013-11-14 2015-12-30 东南大学 A deflection walker reply type suspension beam structure mems
FR3031096A1 (en) * 2014-12-26 2016-07-01 Delfmems Microelectromechanical or nanoelectromechanical device comprising a membrane that is mobile in translation and is profiled to reduce short circuits and the formation of electric arcs
2001-05-25 US US09/866,205 patent/US6803534B1/en active Active
2002-05-14 AU AU2002305598A patent/AU2002305598A1/en not_active Abandoned
2002-05-14 AT AT02734428T patent/AT343544T/en not_active IP Right Cessation
2002-05-14 WO PCT/US2002/015346 patent/WO2002096796A2/en active IP Right Grant
2002-05-14 DE DE2002615642 patent/DE60215642T2/en active Active
2002-05-14 EP EP02734428A patent/EP1395516B1/en active Active
2002-05-24 TW TW91111130A patent/TW582043B/en active
AU2002305598A1 (en) 2002-12-09
AT343544T (en) 2006-11-15
US6803534B1 (en) 2004-10-12
WO2002096796A2 (en) 2002-12-05
WO2002096796A3 (en) 2003-03-13
EP1395516B1 (en) 2006-10-25
EP1395516A2 (en) 2004-03-10
DE60215642D1 (en) 2006-12-07
TW582043B (en) 2004-04-01
JP4704398B2 (en) 2011-06-15 Micro electromechanical system valve and manufacturing method thereof
US20050190023A1 (en) 2005-09-01 Micro-switching element fabrication method and micro-switching element
WO2002059977A2 (en) 2002-08-01 Monolithic switch
JP4580745B2 (en) 2010-11-17 Piezoelectric drive MEMS device