Electricity: electrical systems and devices – Electrostatic capacitors – Variable
Reexamination Certificate
2001-03-30
2002-12-17
Dinkins, Anthony (Department: 2831)
Electricity: electrical systems and devices
Electrostatic capacitors
Variable
C361S277000, C361S298200
Reexamination Certificate
active
06496351
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to microelectromechanical system (MEMS) devices and, more particularly, to multilayer members included in MEMS devices.
BACKGROUND OF THE INVENTION
Microelectromechanical structures (MEMS) and other microengineered devices are presently being developed for a wide variety of applications in view of the size, cost and reliability advantages provided by these devices. For example, one advantageous MEMS device is a variable capacitor in which the interelectrode spacing between a pair of electrodes is controllably varied in order to selectively vary the capacitance between the electrodes. In this regard, conventional MEMS variable capacitors include a pair of electrodes, one of which is typically disposed upon and fixed to the substrate and the other of which is typically carried on a movable actuator or driver. In accordance with MEMS technology, the movable actuator is typically formed by micromachining the substrate such that very small and very precisely defined actuators can be constructed.
While a variable capacitor can be utilized for many applications, tunable filters frequently utilize variable capacitors in order to appropriately tune the filter to pass signals having predetermined frequencies, while rejecting signals having other frequencies. For tunable filters that are utilized for high frequency applications, such as applications involving radio frequency (RF) signals, the tunable filter preferably has a low loss and a high Q, i.e., a high quality factor. Unfortunately, variable capacitors that include electrodes formed of conventional metals generally do not have a sufficiently high Q for high frequency applications. While electrodes formed of superconducting materials would advantageously increase the Q of the resulting variable capacitor, the use of superconducting materials is generally not compatible with the micromachining techniques, such as required to fabricate the actuator of a conventional MEMS variable capacitor. For example, the chemicals, i.e., the etchants, utilized during the micromachining of a substrate would likely harm the acid and water sensitive superconducting materials. In addition, the elevated temperatures, in the range of 400° C. or greater, required for conventional micromachining will cause damage to the temperature-sensitive superconducting materials.
As such, MEMS variable capacitors that have improved performance characteristics are desired for many applications. For example, tunable filters having a higher Q so as to be suitable for filtering high frequency signals are desirable, but are currently large in size, expensive to fabricate and have limited performance characteristics.
SUMMARY OF THE INVENTION
Embodiments according to the present invention provide MEMS devices that include a substrate, an anchor attached to the substrate, and a multilayer member attached to the anchor and spaced apart from the substrate. The multilayer member can have a first portion that is remote from the anchor that curls away from the substrate and a second portion that is adjacent to the anchor that contacts the substrate. In some embodiments, the multilayer member is configured so as to contact the substrate at an intermediate point thereof.
Having the second portion contact the substrate can reduce the spacing between the first portion and the substrate. Reducing the spacing can reduce a voltage level used to actuate the multilayer member relative to the substrate when used, for example, as part of a capacitor, relay, valve or other MEMS device that may move towards and/or away from the substrate.
In some embodiments, the MEMS devices can include connecting members that are attached to the anchors and to the multilayer member. In some embodiments, the connecting members can be serpentine shaped. In some embodiments, the connecting members can be attached to a portion of the multilayer member that is closer to the first portion than the second portion. In other embodiments, the connecting members can be attached to a portion of the multilayer member that is closer to the second portion than the first portion.
In some embodiments according to the present invention, a second anchor can be attached to the substrate and the multilayer member to define an anchor axis which passes through the two anchors. The second portion of the multilayer member can contact the substrate forward of the anchor axis.
In some embodiments according to the present invention, the multilayer member can contact the substrate in response to a thermal effect, such as heating or cooling the multilayer member. In some embodiments according to die present invention, the multilayer member can contact the substrate in response to a difference in tensile stresses between some of the layers included in the multilayer member.
In some embodiments according to the present invention, the MEMS devices can also include a protrusion from the second portion and a receptacle on the substrate. The protrusion can be coupled to the receptacle when the multilayer member is in a first position.
REFERENCES:
patent: 3646413 (1972-02-01), Oomen
patent: 3796976 (1974-03-01), Heng et al.
patent: 4141080 (1979-02-01), Paul et al.
patent: 4244722 (1981-01-01), Tsuya et al.
patent: 4480254 (1984-10-01), Spencer et al.
patent: 4516091 (1985-05-01), Sasser
patent: 4554519 (1985-11-01), Adam
patent: 4619001 (1986-10-01), Kane
patent: 4692727 (1987-09-01), Wakino et al.
patent: 4782313 (1988-11-01), Brant, Jr.
patent: 4849722 (1989-07-01), Cruchon et al.
patent: 4853660 (1989-08-01), Schloemann
patent: 5075600 (1991-12-01), El-Hamamsy et al.
patent: 5162977 (1992-11-01), Paurus et al.
patent: 5164688 (1992-11-01), Larson
patent: 5168249 (1992-12-01), Larson
patent: 5258591 (1993-11-01), Buck
patent: 5312790 (1994-05-01), Sengupta et al.
patent: 5367136 (1994-11-01), Buck
patent: 5406233 (1995-04-01), Shih et al.
patent: 5467067 (1995-11-01), Field et al.
patent: 5479042 (1995-12-01), James et al.
patent: 5504466 (1996-04-01), Chan-Son-Lint et al.
patent: 5543765 (1996-08-01), Cachier
patent: 5568106 (1996-10-01), Fang et al.
patent: 5578976 (1996-11-01), Yao
patent: 5587943 (1996-12-01), Torok et al.
patent: 5589845 (1996-12-01), Yandrofski et al.
patent: 5607631 (1997-03-01), Wolfson et al.
patent: 5640042 (1997-06-01), Koscica et al.
patent: 5640133 (1997-06-01), MacDonald et al.
patent: 5677823 (1997-10-01), Smith
patent: 5696662 (1997-12-01), Bauhahn
patent: 5721194 (1998-02-01), Yandrofski et al.
patent: 5770546 (1998-06-01), Grothe et al.
patent: 5808527 (1998-09-01), De Los Santos
patent: 5818683 (1998-10-01), Fujii
patent: 5830591 (1998-11-01), Sengupta et al.
patent: 5834975 (1998-11-01), Bartlett et al.
patent: 5870007 (1999-02-01), Carr et al.
patent: 5870274 (1999-02-01), Lucas
patent: 5872489 (1999-02-01), Chang et al.
patent: 5972489 (1999-02-01), Chang et al.
patent: 5880921 (1999-03-01), Tham et al.
patent: 5912472 (1999-06-01), Voiglaender et al.
patent: 5912486 (1999-06-01), Summerfelt
patent: 5914553 (1999-06-01), Adams et al.
patent: 5925455 (1999-07-01), Bruzzone et al.
patent: 5926073 (1999-07-01), Hasegawa et al.
patent: 5930165 (1999-07-01), Johnson et al.
patent: 6229683 (2001-05-01), Goodwin-Johansson
Lin et al., “Design, Fabrication, and Testing of a C-Shape Actuator,” 8thInternational Conference on Solid-State Sensors and Actuators and Eurosensors IX. Digest of Technical Papers, Proceedings of the International Solid-State Sensors and Actuators Conference—Transducers ′95, Stockholm, Sweden, 1995, vol. 2, pp. 416-419.
Suh et al., “Organic thermal and electrostatic ciliary microactuator array for object manipulation,” Sensors and Actuators A, Elsevier Sequoia S.A., Lausanne, Ch, vol. 58, No. 1, 1997, pp. 51-60.
Sun et al., “A bistable microrelay based on two-segment multimorph cantilever actuators,” Micro Electro Mechanical Systems, 1998. MEMS 98. Proceedings., The Eleventh Annual International Workshop on Heidelberg, Germany, Jan. 25-29, 1998, New York, NY, pp.154-159.
International Search Report, PCT/IB01/01010, Feb
Hill Edward A.
Mahadevan Ramaswamy
Dinkins Anthony
JDS Uniphase Inc.
Myers Bigel & Sibley & Sajovec
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