Patent ID: 9680439
Date: 2017-06-13
CPC Classifications: H01L,H03H,Y10T

Claim:
1. A method of fabricating a bulk acoustic wave (BAW) resonator device, comprising: forming a bottom electrode over a substrate; forming an etch stop layer over the bottom electrode and the substrate; forming a dielectric layer on the etch stop layer over the bottom electrode and the substrate; forming a photomask over the dielectric layer, the photomask defining an opening over the bottom electrode, wherein the opening is slightly smaller than the bottom electrode; etching a portion of the dielectric layer through the opening of the photomask to the etch stop layer to create a corresponding opening in the dielectric layer and un-etched protruding portions of the dielectric layer; removing the photomask, leaving the un-etched protruding portions of the dielectric layer around the opening in the dielectric layer; and removing at least the un-etched protruding portions of the dielectric layer and a portion of the etch stop layer located over the bottom electrode to provide a planarized surface comprising a top surface of the bottom electrode and an adjacent top surface of the dielectric layer deposited over the substrate.