Flat trench insulation production during manufacture of an integrated deep trench DRAM switching element comprises preparing an etch stop layer on a substrate, structuring, and further processing

摘要

Flat trench insulation production involves etching a deep trench in a substrate, forming a capacitor and a strip in the deep trench, depositing an intermediate layer; depositing hard mask material over intermediate layer; structuring hard mask material layer to prepare openings for flat trenches, etching processes, removing the hard mask layer; and filling the trenches with a dielectric layer. Production of a flat trench insulation during the manufacture of an integrated deep trench DRAM switching element comprises: (a) preparing an etch stop layer on a substrate (10) and structuring; (b) etching a deep trench in the substrate not covered by the etch stop layer; (c) forming a capacitor (54) and a strip in the deep trench; (d) depositing an intermediate layer over the etch stop layer and strip; (e) depositing a hard mask material over the intermediate layer; (f) structuring the hard mask material layer to prepare openings for flat trenches; (g) back etching the intermediate layer and the etch stop layer; (h) etching the substrate and the deep trench; (g) removing the hard mask layer; and (i) filling the trenches with a dielectric layer. Preferred Features: The etch stop layer is made from silicon nitride with a thickness of 100-200 nm. The capacitor is formed by filling the trench with a silicon layer, removing the silicon layer up to the upper surface of the substrate, and depositing a polysilicon layer in the recess. The hard mask layer is made from borosilicate glass and borophosphate glass.