Capacitive sensor for dynamical quantity
View Patent ↗A capacitive sensor for measuring a dynamical quantity based on a change in capacitance has a semiconductor substrate having a weight supported by beams so as to undergo displacement according to the dynamical quantity. The semiconductor substrate is sandwiched between glass substrates on which fixed electrodes are disposed in a position facing the weight with minute gaps existing between the glass substrates and the weight. A substrate electrode is disposed on one of the glass substrates and contacts a part of the semiconductor substrate. A recess having a size equal to or larger than a contact area in which the semiconductor substrate contacts the substrate electrode is formed in the semiconductor substrate, and a contact electrode is disposed in the recess in contact with the substrate electrode.
1. A capacitive dynamical quantity sensor for measuring a dynamical quantity based on a change in capacitance between a weight and a fixed electrode due to displacement of the weight, comprising:
a semiconductor substrate having a weight supported by beams so as to undergo displacement according to the dynamical quantity; and
a glass substrate having a fixed electrode disposed thereon in a position facing the weight such that a minute gap exists between the fixed electrode and the weight and having a substrate electrode disposed thereon in contact with a part of the semiconductor substrate;
wherein the semiconductor substrate has a recess formed therein, the recess having a size equal to or larger than a contact area in which the semiconductor substrate contacts the substrate electrode, a contact electrode is disposed within the recess in contact with the substrate electrode, and plural grooves or plural holes are disposed in a part of the contact electrode.
2. A capacitive dynamical quantity sensor according to claim 1 , wherein a depth of the recess is smaller than a thickness of the substrate electrode.
3. A capacitive dynamical quantity sensor according to claim 1 , wherein a depth of the recess is larger than a thickness of the substrate electrode, and a sum of a thickness of the contact electrode and the thickness of the substrate electrode is larger than the depth of the recess.
4. A capacitive dynamical quantity sensor according to claim 1 , wherein the plural grooves or the plural holes are disposed at even intervals.
5. A capacitive dynamical guantity sensor for measuring a dynamical guantity based on a change in capacitance between a weight and a fixed electrode due to displacement of the weight, comprising:
a semiconductor substrate having a weight supported by beams so as to undergo displacement according to the dynamical guantity; and
a glass substrate having a fixed electrode disposed thereon in a position facing the weight such that a minute gap exists between the fixed electrode and the weight and having a substrate electrode disposed thereon in contact with a part of the semiconductor substrate;
wherein the semiconductor substrate has a recess formed therein, the recess having a size egual to or larger than a contact area in which the semiconductor substrate contacts the substrate electrode, and plural contact electrodes are disposed within the recess in contact with the substrate electrode.
6. A capacitive dynamical quantity sensor according to claim 5 , wherein the plural contact electrodes are disposed at even intervals.
7. A capacitive dynamical quantity sensor according to claim 5 , wherein adjacent contact electrodes are connected together with the same material as that of the contact electrodes.
8. A capacitive dynamical quantity sensor according to claim 5 , wherein each of the contact electrodes contains aluminum.