MEMS device having support structures configured to minimize stress-related deformation and methods for fabricating same
First Claim
1. A method of fabricating a MEMS device, comprising:
- providing a substrate;
depositing an electrode layer over the substrate;
depositing a sacrificial layer over the electrode layer;
patterning the sacrificial layer to form apertures;
forming support structures at least partially within apertures in the sacrificial layer, wherein forming the support structure comprises depositing a layer of conformal support post material over the sacrificial layer and apertures, the support post having an internal residual stress; and
depositing a movable layer over the support structures after forming the support structures, wherein the movable layer comprises a material having an internal residual stress, and wherein the materials of the movable layer and the support structures are selected such that the residual stress in the movable layer is balanced by residual stress in the support structures such that deflection of the movable layer caused by the residual stresses is minimized.
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Accused Products
Abstract
Embodiments of MEMS devices include a movable layer supported by overlying support structures, and may also include underlying support structures. In one embodiment, the residual stresses within the overlying support structures and the movable layer are substantially equal. In another embodiment, the residual stresses within the overlying support structures and the underlying support structures are substantially equal. In certain embodiments, substantially equal residual stresses are be obtained through the use of layers made from the same materials having the same thicknesses. In further embodiments, substantially equal residual stresses are obtained through the use of support structures and/or movable layers which are mirror images of one another.
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Citations
40 Claims
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1. A method of fabricating a MEMS device, comprising:
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providing a substrate; depositing an electrode layer over the substrate; depositing a sacrificial layer over the electrode layer; patterning the sacrificial layer to form apertures; forming support structures at least partially within apertures in the sacrificial layer, wherein forming the support structure comprises depositing a layer of conformal support post material over the sacrificial layer and apertures, the support post having an internal residual stress; and depositing a movable layer over the support structures after forming the support structures, wherein the movable layer comprises a material having an internal residual stress, and wherein the materials of the movable layer and the support structures are selected such that the residual stress in the movable layer is balanced by residual stress in the support structures such that deflection of the movable layer caused by the residual stresses is minimized. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 40)
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16. A MEMS device, comprising:
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a substrate; an electrode layer located over the substrate; a movable layer located over the electrode layer, wherein the movable layer is generally spaced apart from the electrode layer by an air gap, wherein the movable layer comprises a reflective sublayer and a mechanical sublayer, the reflective sublayer on the side of the movable layer facing the electrode layer, and wherein the reflective sublayer comprises a different material than the mechanical sublayer; and rigid support structures formed vertically adjacent the movable layer such that the support structures and the movable layer overlap one another within a support post region, wherein the support structures comprise a first sublayer comprising the same material as the mechanical sublayer and a second sublayer comprising the same material as the reflective sublayer, the first and second sublayers formed of different materials. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. An electromechanical device, comprising:
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a substrate; an electrode layer located over the substrate; a plurality of rigid support structures each comprising a first sublayer of a first material and a second sublayer of a second material, the first and second materials being different from one another; and a movable layer extending over at least a portion of the rigid support structures, wherein the movable layer is generally spaced apart from the electrode layer by an air gap, wherein the movable layer comprises a reflective sublayer and a mechanical sublayer, the reflective sublayer on the side of the movable layer facing the electrode layer, wherein the reflective sublayer comprises the first material and the mechanical sublayer comprises the second material. - View Dependent Claims (36, 37, 38, 39)
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Specification