Patent ID: 8658512

Claim:
A method, comprising: providing a substrate, wherein the substrate comprises a first layer, a second layer, and a third layer and wherein the first layer, the second layer, and the third layer are stacked on each other; etching a plurality of first trenches through the third layer, through the second layer, and into the first layer to define a plurality of first fingers in the third layer and a plurality of second fingers in the first layer, wherein the etching comprises using a single etching mask; removing the second layer in a region where the plurality of first trenches are provided to form a gap between the plurality of first fingers and the plurality of second fingers; etching second trenches through the first layer in a region surrounding the region where the plurality of first trenches are provided, to define a seismic mass connected to the plurality of second fingers; and removing the second layer in a region between the seismic mass and the third layer, thereby releasing the seismic mass and the plurality of second fingers.