Comb drive with non-parallel overlapping comb fingers

Abstract

A comb drive includes an inactive comb finger array and an opposing active comb finger array positioned to oppose the inactive comb finger array and configured to move in a non-linear path relative to the inactive comb finger array, wherein each comb finger array includes a comb spine and a plurality of comb fingers extending from its comb spine, and each comb finger on the active comb finger array is shaped to match a non-parallel profile. The non-parallel profile may be tapered, curved, or selected to linearize the capacitance in a gap between adjacent comb fingers from the inactive comb finger array when a comb finger from the active comb finger array moves through the gap.

1 . A method of fabricating a comb drive comprising:
 forming on a substrate, with a first lithography process, a first comb structure comprising a first set of comb fingers extending in a first direction from a first comb spine;   forming on the substrate, with the first lithography process, a second comb structure comprising a second set of comb fingers extending in a second direction from a second comb spine;   wherein the first direction opposes the second direction;   each comb finger is tapered such that a proximal comb finger end is wider than a distal comb finger end; and   the first set of comb fingers interleaves with the second set of comb fingers.   
     
     
         2 . The method of  claim 1 , further comprising, etching each of the first comb structure and the second comb structure. 
     
     
         3 . The method of  claim 2 , further comprising depositing an insulation layer and a conductive layer to each of the first comb structure and the second comb structure. 
     
     
         4 . The method of  claim 3 , further comprising directional etching or isotropic etching each of the first comb structure and the second comb structure. 
     
     
         5 . The method of  claim 1 , further comprising:
 removing the first comb structure and the second comb structure from the substrate, such that the first set of comb fingers remains interleaved with the second set of comb fingers;   and mechanically coupling the first comb structure to a component sub-structure.   
     
     
         6 . The method of  claim 5 , further comprising:
 mechanically coupling the second comb structure to an actuator stage assembly; and   activating the comb drive by electrifying the comb fingers, without first separating the first comb structure from the second comb structure.   
     
     
         7 - 20 . (canceled)