Humidity sensor and semiconductor device including the same
View Patent ↗Provided is a humidity sensor whose electrode is set to have an island-like configuration and is enclosed by a humidity sensitive film. As a result, in the humidity sensor, adhesion property between the humidity sensitive films on the electrode is enhanced and thus high reliability is achieved.
1. A humidity sensor comprising:
a substrate;
a first insulating film formed over the substrate;
a first metal wiring layer disposed over the first insulating film;
a second insulating film formed over the first metal wiring layer;
a second metal wiring layer disposed over the second insulating film and formed with a plurality of unit cells, each comprising a first electrode and a second electrode which separately encompasses the first electrode in its entirety so as to have a capacitance between the first and second electrodes, and the first electrode being in electrical contact with the first metal wiring layer through the second insulating film; and
a humidity sensitive film formed over the first electrode and the second electrode.
2. A humidity sensor according to claim 1 , wherein the substrate comprises a semiconductor substrate.
3. A humidity sensor according to claim 1 , wherein each of the plurality of unit cells has a silicon nitride film as a protective film.
4. A humidity sensor according to claim 1 , wherein the first electrode and the second electrode have a barrier layer thereunder which contains less than 10% of nitrogen in terms of an atomic weight.
5. A humidity sensor according to claim 1 , wherein a capacitance of each of the unit cells can be measured.
6. A humidity sensor according to claim 1 , wherein the plurality of unit cells are formed as a grid pattern.
7. A humidity sensor according to claim 1 , wherein the first electrode is in the shape of a square and the second electrode squarely encompasses the first electrode.
8. A humidity sensor according to claim 1 , wherein the first and second electrodes are shaped as projections which are interdigitized.
9. A semiconductor device, comprising:
the humidity sensor according to claim 1 ; and
an integrated circuit including a signal processing circuit, wherein the humidity sensor and the integrated circuit are disposed on the substrate.
10. A semiconductor device according to claim 9 , further comprising a silicon nitride film as a protective film.
11. A semiconductor device according to claim 10 , wherein the silicon nitride film on the integrated circuit is thicker than the silicon nitride film on the humidity sensor.