Methods for forming layers within a mems device using liftoff processes

Abstract

Certain MEMS devices include layers patterned to have tapered edges. One method for forming layers having tapered edges includes the use of an etch leading layer. Another method for forming layers having tapered edges includes the deposition of a layer in which the upper portion is etchable at a faster rate than the lower portion. Another method for forming layers having tapered edges includes the use of multiple iterative etches. Another method for forming layers having tapered edges includes the use of a liftoff mask layer having an aperture including a negative angle, such that a layer can be deposited over the liftoff mask layer and the mask layer removed, leaving a structure having tapered edges.

We claim: 
     
         1 . An electromechanical device, comprising:
 an electrode layer located over a substrate;   a conductive movable layer located over the conductive layer, wherein at least a portion of the conductive movable layer is spaced apart from the electrode layer by an air gap;   at least one support structure located adjacent the conductive movable layer, wherein an outer periphery of the support structure comprises an outwardly tapered edge.   
     
     
         2 . The electromechanical device of  claim 1 , additionally comprising a dielectric layer located over the electrode layer. 
     
     
         3 . The electromechanical device of  claim 1 , wherein the at least one support structure underlies at least a portion of the conductive movable layer. 
     
     
         4 . The electromechanical device of  claim 1 , wherein the at least one support structure overlies at least a portion of the conductive movable layer. 
     
     
         5 . The electromechanical device of  claim 1 , wherein the at least one support structure is formed via a liftoff process. 
     
     
         6 . The electromechanical device of  claim 1 , wherein the electromechanical device comprises an interferometric modulator. 
     
     
         7 . The electromechanical device of  claim 1 , additionally comprising:
 a processor that is configured to communicate with the conductive movable layer, the processor being configured to process image data; and   a memory device that is configured to communicate with the processor.   
     
     
         8 . The electromechanical device of  claim 7 , additionally comprising a driver circuit configured to send at least one signal to the conductive movable layer. 
     
     
         9 . The electromechanical device of  claim 8 , additionally comprising a controller configured to send at least a portion of the image data to the driver circuit. 
     
     
         10 . The electromechanical device of  claim 7 , additionally comprising an image source module configured to send the image data to the processor. 
     
     
         11 . The electromechanical device of  claim 10 , wherein the image source module comprises at least one of a receiver, transceiver, and transmitter. 
     
     
         12 . The electromechanical device of  claim 7 , additionally comprising an input device configured to receive input data and to communicate the input data to the processor. 
     
     
         13 . A method of fabricating an electromechanical device, the method comprising:
 forming an electrode layer over a substrate;   forming a sacrificial layer over the electrode layer;   forming a conductive movable layer over the sacrificial layer;   forming a mask having at least one aperture extending therethrough, the mask having a negative angle at the edge of the at least one aperture;   depositing a layer of support structure material over the mask and the at least one aperture; and   removing the mask to form a support structure.   
     
     
         14 . The method of  claim 13 , wherein forming the support structure is done prior to forming the conductive movable layer. 
     
     
         15 . The method of  claim 13 , wherein forming the conductive movable layer is done prior to forming the support structure. 
     
     
         16 . The method of  claim 13 , additionally comprising performing a release etch to remove the sacrificial layer, forming an air gap between portions of the conductive movable layer and the electrode layer. 
     
     
         17 . An electromechanical device, comprising:
 an electrode layer located over a substrate;   a conductive movable layer located over the conductive layer, wherein at least a portion of the conductive movable layer is spaced apart from the electrode layer by an air gap;   at least one support structure located adjacent the conductive movable layer, wherein the at least one support structure comprises means for facilitating conformal deposition of an overlying layer.   
     
     
         18 . The electromechanical device of  claim 17 , wherein the means for facilitating conformal deposition of an overlying layer comprise an outwardly tapered edge at an outer periphery of the support structure. 
     
     
         19 . The electromechanical device of  claim 17 , wherein the at least one support structure underlies at least a portion of the conductive movable layer. 
     
     
         20 . The electromechanical device of  claim 17 , wherein the at least one support structure overlies at least a portion of the conductive movable layer.