Film stack for manufacturing micro-electromechanical systems (MEMS) devices
View Patent ↗This invention provides a precursor film stack for use in the production of MEMS devices. The precursor film stack comprises a carrier substrate, a first layer formed on the carrier substrate, a second layer of an insulator material formed on the first layer, and a third layer of a sacrificial material formed on the second layer.
1. A film stack for the production of MEMS devices, the film stack comprising:
a substrate;
a first layer formed over the substrate, said first layer comprising a conductive material;;
a second layer formed over the first layer, said second layer comprising an insulator material; and
a third layer formed on the second layer, said third layer comprising a sacrificial material, wherein said third layer is formed prior to processing of said first and second layers which takes place after the deposition of said first and second layers.
2. The stack of claim 1 , wherein the first, the second and the third layers are formed using a deposition technique.
3. The stack of claim 1 , wherein the first layer comprises at least one of the following: a single metal, a conductive oxide, a fluoride, a suicide, and a conductive polymer.
4. The stack of claim 3 , further comprising an optical compensation layer formed over the substrate, the optical compensation layer comprising a material of a finite extinction coefficient.
5. The stack of claim 4 , wherein the optical compensation layer is formed over the first layer.
6. The stack of claim 4 , wherein the optical compensation layer is formed under the first layer.
7. The stack of claim 4 , wherein the optical compensation layer comprises a material comprising at least one of the following: Zirconia and Hafnia.
8. The stack of claim 4 , wherein the optical compensation layer comprises a material comprising at least one of the following: an oxide, a nitride, and a fluoride.
9. The stack of claim 1 , wherein the first layer comprises at least one of the following: Chromium, Tungsten, and Molybdenum.
10. The stack of claim 1 , wherein the first layer comprises at least one of the following: indium tin oxide (ITO), zinc oxide (ZnO), and titanium nitride (TiN).
11. The stack of claim 1 , wherein the insulator material comprises at least one of the following: an oxide, a polymer, a fluoride, a ceramic and a nitride.
12. The stack of claim 11 , wherein the sacrificial material is etchable using a Xenon difluoride gas.
13. The stack of claim 1 , wherein the sacrificial material is selected from the group consisting of silicon, molybdenum, and tungsten.
14. The stack of claim 1 , wherein the first layer comprises a plurality of sublayers, at least one of the sublayers comprising a conductive material.
15. The stack of claim 14 , wherein the sublayer furthest from the carrier substrate defines an optical layer.
16. The stack of claim 15 , wherein the optical layer comprises a substantially non-conductive material.
17. The stack of claim 15 , wherein the optical layer comprises a substantially conductive material.
18. The stack of claim 1 , wherein at least one of the second layer and the third layer comprises a plurality of sublayers.
19. The stack of claim 1 , further comprising an optical layer deposited between the second and third layers.
20. The stack of claim 19 , wherein the optical layer comprises a substantially non-conductive material.
21. The stack of claim 1 , wherein the third layer comprises at least two sublayers, each sublayer alternating with the other, wherein each sublayer can be etched by the same release etchant, but has a different etch chemistry so that the sublayers define etch stops for each other.
22. The stack of claim 21 , wherein the third layer comprises a sublayer of molybdenum that alternates with a sublayer of silicon.