Well-controlled cmp process for dram technology

Abstract

A new method of maintaining good control of the dielectric thickness over a top capacitor plate during planarization by CMP by introducing a CMP stop layer under the topmost dielectric layer is described. Semiconductor device structures, including a node contact region, are provided in and on a semiconductor substrate. A bottom plate electrode is formed contacting the node contact region through an opening in a first insulating layer. A capacitor dielectric layer is deposited overlying the bottom plate electrode. A second conducting layer is deposited overlying the capacitor dielectric to form a top plate electrode of the capacitor. A second insulating layer is deposited overlying the second conducting layer. A silicon nitride polish stop layer is deposited overlying the second insulating layer. The polish stop layer, second insulating layer, second conducting layer, and capacitor dielectric layer are patterned to form the DRAM integrated circuit device. A third insulating layer is deposited overlying the first insulating layer and the polish stop layer of the DRAM integrated circuit device. The third insulating layer is planarized by chemical mechanical polishing stopping at the polish stop layer. The polish stop layer protects the top capacitor plate from damage.