Patent ID: 6395620
Filing Date: 2002-05-28
Classification: H01L

Abstract:
A method for forming a planar surface using a self-aligned mask segment over a low density field on a semiconductor wafer having a contoured front face with a low region between high points, the method comprising:depositing a fill layer over the front face of the wafer to substantially conform to the front face of the wafer, the fill layer having a depression over the low region, a top surface over the high points of the wafer, a bottom surface under the top surface, and a first depth defined by a first material between the top surface and the bottom surface, wherein the first material extends throughout the first depth between the top surface and the bottom surface; covering the fill layer with a cover layer, the cover layer having an upper portion on the top surface of the fill layer and a lower portion in the depression; removing a portion of the cover layer from the fill layer to form a mask segment from the lower portion of the cover layer and to expose the first material over the bottom surface of the fill layer, the mask segment being self-aligned with the low region; removing portions of the fill layer adjacent to the mask segment to form a shoulder surface of the first material at an intermediate elevation of the first depth over the high points and to form a raised feature including the mask segment positioned over the low region, wherein at least a portion of the raised feature is higher than the shoulder surface; and further removing the first material at the shoulder surface, the mask segment and the raised feature using a chemical-mechanical planarizing process that terminates at the high points.