Patent ID: 10163680

Abstract:
A method of forming an IC includes forming a buried layer (BL) doped a second type in a substrate doped a first type. Deep trenches are etched including narrower inner trench rings and wider outer trench rings through to the BL. A first deep sinker implanting uses ions of the second type with a first dose, a first energy, and a first tilt angle. A second deep sinker implant uses ions of the second type with a second dose that<the first dose, a second energy>than the first energy, and a second tilt angle<the first tilt angle. The outer trench rings outside and inner trench rings are dielectric lined. The dielectric lining is removed from a bottom of the outer trench rings. The outer trench rings are filled with an electrically conductive filler material that contacts the substrate and fills the inner trench rings.