MEMS DEVICE AND CORRESPONDING MICROMECHANICAL STRUCTURE WITH INTEGRATED COMPENSATION OF THERMO-MECHANICAL STRESS
First Claim
1. A micromechanical structure having a first axis of symmetry, the micromechanical structure comprising:
- a semiconductor substrate;
a stator structure that is fixed with respect to said substrate and includes fixed sensing electrodes;
a rotor structure having a suspended mass that is mobile with respect to said substrate and to said stator structure in response to an external acceleration, said fixed sensing electrodes being capacitively coupled to said rotor structure; and
a compensation structure configured to compensate for thermo-mechanical strains that occur within said micromechanical structure, said compensation structure including stator compensation electrodes that are fixed with respect to said substrate and are capacitively coupled to said rotor structure, the compensation electrodes being symmetrically arranged relative to said fixed sensing electrodes with respect to the first axis of symmetry.
2 Assignments
0 Petitions
Accused Products
Abstract
A micromechanical structure of a MEMS device, integrated in a die of semiconductor material provided with a substrate and having at least a first axis of symmetry lying in a horizontal plane, has a stator structure, which is fixed with respect to the substrate, and a rotor structure, having a suspended mass, mobile with respect to the substrate and to the stator structure as a result of an external action, the stator structure having fixed sensing electrodes capacitively coupled to the rotor structure; a compensation structure is integrated in the die for compensation of thermo-mechanical strains. The compensation structure has stator compensation electrodes, which are fixed with respect to the substrate, are capacitively coupled to the rotor structure, and are arranged symmetrically to the fixed sensing electrodes with respect to the first axis of symmetry.
15 Citations
22 Claims
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1. A micromechanical structure having a first axis of symmetry, the micromechanical structure comprising:
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a semiconductor substrate; a stator structure that is fixed with respect to said substrate and includes fixed sensing electrodes; a rotor structure having a suspended mass that is mobile with respect to said substrate and to said stator structure in response to an external acceleration, said fixed sensing electrodes being capacitively coupled to said rotor structure; and a compensation structure configured to compensate for thermo-mechanical strains that occur within said micromechanical structure, said compensation structure including stator compensation electrodes that are fixed with respect to said substrate and are capacitively coupled to said rotor structure, the compensation electrodes being symmetrically arranged relative to said fixed sensing electrodes with respect to the first axis of symmetry. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A MEMS device comprising:
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a first micromechanical structure having a first axis of symmetry, the micromechanical structure including; a semiconductor substrate; a stator structure fixed to the substrate and includes fixed sensing electrodes; a rotor structure having a suspended mass that is moveable relative to the substrate and to the stator structure in response to an external acceleration, the fixed sensing electrodes being capacitively coupled to the rotor structure; and a compensation structure configured to compensate for thermo-mechanical strains that occur within the micromechanical structure, the compensation structure including stator compensation electrodes that are fixed with respect to the substrate and are capacitively coupled to the rotor structure, the compensation electrodes being symmetrically arranged relative to the fixed sensing electrodes with respect to the first axis of symmetry; and an electronic circuit coupled to the first micromechanical structure and configured to determine a capacitive sensing signal as a function of a first capacitance of a first sensing capacitor formed between said fixed sensing electrodes and the rotor structure and determine a capacitive compensation signal as a function of a second capacitance of a first compensation capacitor formed between the stator compensation electrodes and the rotor structure, wherein the electronic circuit is further configured to determine a resulting signal that compensates for thermo-mechanical strain as a function of the capacitive sensing signal and the capacitive compensation signal. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A micromechanical structure having a first axis of symmetry and a second axis of symmetry perpendicular to the first axis, the micromechanical structure comprising:
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a semiconductor substrate having a surface; a stator structure that is fixed the base surface and includes fixed sensing electrodes; a rotor structure that includes rotor sensing electrodes that move relative to the substrate and to said stator structure in response to an external acceleration, each of the fixed sensing electrodes being capacitively coupled to a respective rotor sensing electrode and forming a sensing capacitor; a compensation rotor structure that includes compensation rotor electrodes; a compensation stator structure that includes compensation stator electrodes, each of the compensation stator electrodes being capactively coupled to a respective compensation rotor electrode and forming a compensation capacitor, the compensation capacitors being symmetrically arranged relative to the sensing capacitors with respect to the first axis of symmetry. - View Dependent Claims (19, 20, 21, 22)
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Specification