Method of manufacturing a temperature-compensated micro-electromechanical device
First Claim
1. A method, comprising:
- forming a first suspended mass in a semiconductor substrate, the first suspended mass being coupled to the semiconductor substrate and movable with respect to the semiconductor substrate, the first suspended mass including a first plurality of movable electrodes that are capacitively coupled to a first plurality of fixed electrodes; and
forming a second suspended mass in the semiconductor substrate, the second suspended mass including a second plurality of fixed electrodes that are capacitively coupled to a third plurality of fixed electrodes, the second suspended mass and the second plurality of fixed electrodes being rigidly coupled to the semiconductor substrate to prevent movement of the second suspended mass and the second plurality of fixed electrodes relative to the semiconductor substrate, the first suspended mass and the second suspended mass being configured to undergo equal strains as a result of thermal expansion of the semiconductor substrate.
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Abstract
Methods of forming micro-electromechanical device include a semiconductor substrate, in which a first microstructure and a second microstructure of reference are integrated. The first microstructure and the second microstructure are arranged in the substrate so as to undergo equal strains as a result of thermal expansions of the substrate. Furthermore, the first microstructure is provided with movable parts and fixed parts with respect to the substrate, while the second microstructure has a shape that is substantially symmetrical to the first microstructure but is fixed with respect to the substrate. By subtracting the changes in electrical characteristics of the second microstructure from those of the first, variations in electrical characteristics of the first microstructure caused by changes in thermal expansion or contraction can be compensated for.
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Citations
19 Claims
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1. A method, comprising:
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forming a first suspended mass in a semiconductor substrate, the first suspended mass being coupled to the semiconductor substrate and movable with respect to the semiconductor substrate, the first suspended mass including a first plurality of movable electrodes that are capacitively coupled to a first plurality of fixed electrodes; and forming a second suspended mass in the semiconductor substrate, the second suspended mass including a second plurality of fixed electrodes that are capacitively coupled to a third plurality of fixed electrodes, the second suspended mass and the second plurality of fixed electrodes being rigidly coupled to the semiconductor substrate to prevent movement of the second suspended mass and the second plurality of fixed electrodes relative to the semiconductor substrate, the first suspended mass and the second suspended mass being configured to undergo equal strains as a result of thermal expansion of the semiconductor substrate. - View Dependent Claims (2, 3, 4, 5, 6, 18)
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7. A method, comprising:
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forming a first suspended mass in a semiconductor substrate, the first suspended mass being suspended relative to the semiconductor substrate and flexibly coupled to the semiconductor substrate to allow movement of the first suspended mass relative to the semiconductor substrate, the first suspended mass including a first plurality of movable electrodes that are capacitively coupled to a first plurality of fixed electrodes; and forming a second suspended mass in the semiconductor substrate at the same time the first suspended mass is formed, the second suspended mass being suspended relative to the semiconductor substrate, the second suspended mass including a second plurality of fixed electrodes that are capacitively coupled to a third plurality of fixed electrodes, the second suspended mass and the second plurality of fixed electrodes being rigidly coupled to the semiconductor substrate to prevent movement of the second suspended mass and the second plurality of fixed electrodes relative to the semiconductor substrate, the first and second suspended masses being configured to undergo substantially equal strain due to thermal expansion of the semiconductor substrate. - View Dependent Claims (8, 9)
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10. A method comprising:
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forming a first mass in a semiconductor substrate, the first mass being suspended relative to the semiconductor substrate, the first mass having a first dimension that is moveable relative to the semiconductor substrate, the first mass including a first plurality of movable electrodes that are capacitively coupled to a first plurality of fixed electrodes; and forming a second mass in the semiconductor substrate, the second mass being suspended relative to the semiconductor substrate, the second mass having a second dimension, the second mass including a second plurality of fixed electrodes that are capacitively coupled to a third plurality of fixed electrodes, the second mass and the second plurality of fixed electrodes being rigidly fixed to the semiconductor substrate to prevent movement of the second mass and the second plurality of fixed electrodes relative to the semiconductor substrate, the second mass being substantially equal to the first mass, the second mass being configured to undergo substantially equal strain as the first mass when the semiconductor substrate thermally expands. - View Dependent Claims (11)
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12. A method comprising:
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in a semiconductor substrate, forming a first mass that is suspended relative to the semiconductor substrate and configured to move relative to the semiconductor substrate, the first mass including a first plurality of movable electrodes that are capacitively coupled to a first plurality of fixed electrodes; and in the semiconductor substrate, forming a second mass that is suspended relative to the semiconductor substrate and is symmetrical with the first mass with respect to an axis of the semiconductor substrate, the second mass including a second plurality of fixed electrodes that are capacitively coupled to a third plurality of fixed electrodes, the second mass and the second plurality of fixed electrodes being rigidly coupled to the semiconductor substrate to prevent movement of the second mass and the second plurality of fixed electrodes relative to the semiconductor substrate, the first and second masses being configured to undergo substantially equal strain due to thermal expansion of the semiconductor substrate. - View Dependent Claims (13, 14, 19)
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15. A method comprising:
forming a micro-electromechanical device in a semiconductor substrate of semiconductor material, wherein forming includes; forming a first body having a first mass that is suspended above and coupled to the semiconductor substrate, the first body being configured to move with respect to the semiconductor substrate along a first axis, the first body being configured to undergo a first strain due to thermal expansion of the semiconductor substrate, the first body including a first plurality of movable electrodes that are capacitively coupled to a second plurality of fixed electrodes; and forming a second body having a second mass that is substantially equal to the first mass of the first body, the second body including a second plurality of fixed electrodes that are capacitively coupled to a third plurality of fixed electrodes, the second body and the second plurality of fixed electrodes being rigidly coupled to the semiconductor substrate to prevent movement of the second body and the second plurality of fixed electrodes with respect to the semiconductor substrate, the second body being configured to undergo a second strain due to thermal expansion of the semiconductor substrate, the second strain being substantially similar to the first strain. - View Dependent Claims (16, 17)
Specification