Set of stepped surfaces formation for a multilevel interconnect structure

摘要

A trench can be formed through a stack of alternating plurality of first material layers and second material layers. A dielectric material liner and a trench fill material portion can be formed in the trench. The dielectric material liner and portions of first material layer can be simultaneously etched to form laterally-extending cavities having level-dependent lateral extents. A set of stepped surfaces can be formed by removing unmasked portions of the second material layers. Alternately, an alternating sequence of processing steps including vertical etch processes and lateral recess processes can be employed to laterally recess second material layers and to form laterally-extending cavities having level-dependent lateral extents. Lateral cavities can be simultaneously formed in multiple levels such that levels having laterally-extending cavities of a same lateral extent are offset across multiple integrated cavities.

主权项

1. A method of forming a three-dimensional structure, comprising:
forming a stack including an alternating plurality of first material layers and second material layers on a substrate; forming a trench vertically extending through the stack; forming a dielectric material liner on a bottom surface and sidewalls of the trench; forming a trench fill material portion within the trench on the dielectric material liner, wherein a top surface of the trench fill material portion is recessed below a topmost surface of the dielectric material liner; removing portions of the dielectric material liner and portions of the first material layers employing an etch process, wherein, for each pair of an overlying first material layer and an underlying first material layer, the overlying first material layer is laterally recessed to a greater lateral extent than the underlying first material layer; wherein the etch process simultaneously removes portions of the dielectric material liner and the portions of the first material layers; and wherein the etch process is an isotropic etch process that is selective to the second material layers and the trench fill material portion.