US5646348A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Micromechanical sensor with a guard band electrode and fabrication technique therefor
Assignee: Charles Stark Draper Laboratory Inc
•
Filing: 1995-09-05
•
Granted: 1997-07-08
•
Expires: 2015-09-05
Abstract
Abstract An electrostatically actuated micromechanical sensor having a guard band electrode for reducing the effect of transients associated with a dielectric substrate of the sensor. A proof mass, responsive to an input, is suspended over the substrate and one or more electrodes are disposed on the substrate in electrostatic communication with the proof mass to sense the input acceleration and/or to torque the proof mass back to a null position. A guard band electrode is disposed over the dielectric substrate in overlapping relationship with the electrodes and maintains the surface of the substrate at a reference potential, thereby shielding the proof mass from transients and enhancing the accuracy of the sensor. A dissolved wafer process for fabricating the micromechanical sensor is described in which the proof mass is defined by a boron doping step. An alternative fabrication technique is also described in which the proof mass is defined by an epitaxial layer.
Inventors
- 👤 Paul Greiff
- 👤 Jerome B. Sohn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:33
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/02; G01P15/08; G01P15/13; G01P15/131; G01P15/0802; G01P15/125; G01P2015/0805; G01P2015/0822; G01P2015/0825; G01P2015/0831
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
82 words
A method of fabricating a micromechanical sensor comprising the steps of: providing a silicon substrate with a P+ epitaxial layer doped with boron to a concentration greater than approximately 10 20 thereover; selectively etching said silicon substrate so as to define a proof mass in said silicon substrate wherein said epitaxial layer provides an etch stop; depositing a sense electrode responsive to an excitation signal on a glass substrate; and bonding said epitaxial layer to said glass substrate to provide said sensor.
Claim 2
Independent Claim
82 words
A method of fabricating a micromechanical sensor comprising the steps of: providing a silicon substrate with a P+ epitaxial layer doped with boron to a concentration greater than approximately 10 20 thereover; selectively etching said silicon substrate so as to define a proof mass in said silicon substrate wherein said epitaxial layer provides an etch stop; depositing a sense electrode responsive to an excitation signal on a glass substrate; and bonding said epitaxial layer to said glass substrate to provide said sensor.
Claim 3
Dependent Claim
61 words
The method recited in claim 1 further comprising the steps of patterning a selected portion of said epitaxial layer with resist; and etching said epitaxial layer to form a post extending from said epitaxial layer and to define a thickness of said epitaxial layer to provide said proof mass of said sensor, wherein said post is bonded to said glass substrate.
Claim 4
Dependent Claim
25 words
The method recited in claim 1 further comprising the step of removing said silicon substrate once said epitaxial layer is bonded to said glass substrate.
Claim 5
Dependent Claim
21 words
The method recited in claim 3 wherein said removing step includes the step of etching said silicon substrate with EDP etchant.
Claim 6
Independent Claim
72 words
A method of fabricating a micromechanical sensor comprising the steps of: providing a silicon substrate with an epitaxial layer thereover in which a proof mass of said sensor is formed; depositing a sense electrode responsive to an excitation signal on a glass substrate; bonding said epitaxial layer to said glass substrate to provide said sensor; and depositing a guard band electrode on said glass substrate in overlapping relationship with said sense electrode.
Claim 7
Independent Claim
72 words
A method of fabricating a micromechanical sensor comprising the steps of: providing a silicon substrate with an epitaxial layer thereover in which a proof mass of said sensor is formed; depositing a sense electrode responsive to an excitation signal on a glass substrate; bonding said epitaxial layer to said glass substrate to provide said sensor; and depositing a guard band electrode on said glass substrate in overlapping relationship with said sense electrode.
Claim 8
Dependent Claim
42 words
The method recited in claim 5 wherein said guard band depositing step further comprises the step of depositing an insulating layer over said glass substrate in overlapping relationship with said sense electrode and depositing said guard band electrode over said insulating layer.
Claim 9
Dependent Claim
153 words
A micromechanical sensor device comprising: a dielectric substrate having a surface; a proof mass comprising an epitaxial layer suspended over said surface of said dielectric substrate, said proof mass being responsive to an input stimulus and forming a first capacitor plate; a first electrode disposed over said surface of said dielectric substrate for coupling an excitation signal to said proof mass and forming a second capacitor plate; a second electrode for sensing out-of-plane deflection of said proof mass; an insulating layer disposed over said surface of said dielectric substrate in overlapping relationship with a portion of said first electrode and said second electrode; and a guard band electrode disposed over said insulating layer so as to overlap said portion of said first electrode and said portion of said second electrode, said guard band electrode receiving a reference potential for shielding said proof mass from spurious charge on said surface of the dielectric substrate.
Claim 10
Dependent Claim
153 words
A micromechanical sensor device comprising: a dielectric substrate having a surface; a proof mass comprising an epitaxial layer suspended over said surface of said dielectric substrate, said proof mass being responsive to an input stimulus and forming a first capacitor plate; a first electrode disposed over said surface of said dielectric substrate for coupling an excitation signal to said proof mass and forming a second capacitor plate; a second electrode for sensing out-of-plane deflection of said proof mass; an insulating layer disposed over said surface of said dielectric substrate in overlapping relationship with a portion of said first electrode and said second electrode; and a guard band electrode disposed over said insulating layer so as to overlap said portion of said first electrode and said portion of said second electrode, said guard band electrode receiving a reference potential for shielding said proof mass from spurious charge on said surface of the dielectric substrate.
Claim 11
Dependent Claim
29 words
The micromechanical sensor device recited in claim 7 wherein said proof mass is suspended over said surface of said dielectric substrate by a post portion of said epitaxial layer.
Claim 12
Dependent Claim
16 words
The micromechanical sensor device recited in claim 7 wherein said dielectric substrate is comprised of glass.
References Cited (Backward Citations)
US32931A
Cited
US33479A
Cited
US3053095A
Cited
US3251231A
Cited
US3370458A
Cited
US3696429A
Cited
US3913035A
Cited
US4044305A
Cited
US4468584A
Cited
US4108553A
Cited
US4155257A
Cited
US4122448A
Cited
US4144764A
Cited
US4234666A
Cited
US4222270A
Cited
US4347478A
Cited
US4290052A
Cited
US4321500A
Cited
US4336718A
Cited
US4342227A
Cited
US4499778A
Cited
US4381672A
Cited
US4447753A
Cited
US4452092A
Cited
US4502042A
Cited
US4406992A
Cited
US4484382A
Cited
US4483194A
Cited
US4495499A
Cited
US4414852A
Cited
US4495820A
Cited
US4654663A
Cited
US4426768A
Cited
US4411741A
Cited
US4665605A
Cited
US4592242A
Cited
US4478077A
Cited
US4478076A
Cited
US4651564A
Cited
US4621925A
Cited
US4596158A
Cited
US4596627A
Cited
US4522072A
Cited
US4490772A
Cited
US4619001A
Cited
US4590801A
Cited
US4585083A
Cited
US4628283A
Cited
US4783237A
Cited
US4600934A
Cited
US4653326A
Cited
US4524619A
Cited
USRE32931E
Cited
USRE33479E
Cited
US4538461A
Cited
US4899587A
Cited
US4598585A
Cited
US4699006A
Cited
US4671112A
Cited
US4629957A
Cited
US4674180A
Cited
US4680606A
Cited
US4644793A
Cited
US4706374A
Cited
US4674319A
Cited
US4705659A
Cited
US4735506A
Cited
US4764244A
Cited
US4639690A
Cited
US4679434A
Cited
US4744248A
Cited
US4744249A
Cited
US4750364A
Cited
US4792676A
Cited
GB2183040B
Cited
US4761743A
Cited
US4736629A
Cited
US4747312A
Cited
US4712439A
Cited
US4670092A
Cited
US4869107A
Cited
US4943032A
Cited
US4776924A
Cited
US4743789A
Cited
US4727752A
Cited
US4884446A
Cited
US4834538A
Cited
US4948757A
Cited
US4805456A
Cited
US5013396A
Cited
US4881410A
Cited
US4815472A
Cited
US4851080A
Cited
US5054320A
Cited
US4898032A
Cited
US4789803A
Cited
US5194402A
Cited
US4916520A
Cited
US4808948A
Cited
US5060039A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-07 | 2001-01-06 | 2001-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-07 | 2005-01-06 | 2005-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-07 | 2009-01-06 | 2009-07-08 | $7700.00 | Window Closed / Lapsed |