Patent ID: 11972954
Assignee: SANDISK TECHNOLOGIES, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of forming a semiconductor structure, comprising:
forming an alternating stack of first material layers and second material layers over a semiconductor material layer;
forming a patterning film over the alternating stack;
forming openings through the patterning film;
forming via openings through the alternating stack at least to a top surface of the semiconductor material layer by performing a first anisotropic etch process that transfers a pattern of the openings in the patterning film;
forming a cladding liner on a top surface of the patterning film and sidewalls of the openings in the pattering film; and
vertically extending the via openings through the semiconductor material layer by performing a second anisotropic etch process employing the cladding liner as an etch mask.