Methods for stiction reduction in MEMS sensors
A method of the invention includes reducing stiction of a MEMS device by providing a conductive path for electric charge collected on a bump stop formed on a substrate. The bump stop is formed by depositing and patterning a dielectric material on the substrate, and the conductive path is provided by a conductive layer deposited on the bump stop. The conductive layer can also be roughened to reduce stiction.
1. A MEMS device comprising:
a MEMS actuator;
a substrate opposing the MEMS actuator; and
a bump stop formed on the substrate to limit motion of the MEMS actuator,
wherein the bump stop is formed from a dielectric material and covered with a first conductive layer, a conductive path formed by the first conductive layer thereby substantially reducing electric charge collected on the bump stop.
2. The MEMS device of claim 1 , further comprising a second conductive layer between the substrate and the bump stop.
3. The MEMS device of claim 2 , wherein the second conductive layer is an electrode.
4. The MEMS device of claim 2 , wherein a portion of the second conductive layer is isolated.
5. The MEMS device of claim 2 , wherein a portion of the second conductive layer is isolated and a voltage potential is applied to the portion of the first conductive layer.
6. The MEMS device of claim 5 , where in the voltage potential is substantially the same as that of the MEMS actuator.
7. The MEMS device of claim 5 , where in the voltage potential has the same polarity as that of the MEMS actuator.
8. The MEMS device of claim 1 , wherein the first conductive layer has a rough surface to reduce contact area with the MEMS actuator.
9. The MEMS device of claim 1 , wherein the substrate is a semiconductor substrate.
10. The MEMS device of claim 1 , wherein the substrate includes electrical components.
11. The MEMS device of claim 1 , wherein the first conductive layer physically contacts the bump stop.
12. The MEMS device of claim 1 , wherein the bump stop is partially enclosed by the first conductive layer.