The Marbury Law Group PLLC
Vertical NAND and method of making thereof using sequential stack etching and self-aligned landing pad
Alignment between memory openings through multiple tier structures can be facilitated employing a temporary landing pad. The temporary landing pad can have a greater area than the horizontal cross-sectional area of a first memory opening through a first tier structure including a first alternating stack of first insulating layers and first spacer material layers. An upper portion of a first memory film is removed, and a sidewall of an insulating cap layer that defines the first memory opening can be laterally recessed to form a recessed cavity. A sacrificial fill material is deposited in the recessed cavity to form a sacrificial fill material portion, which functions as the temporary landing pad for a second memory opening that is subsequently formed through a second tier structure including second insulating layers and second spacer material layers. A memory stack structure can be formed through the first and second tier structures.
SANDISK TECHNOLOGIES LLC
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Yanli Jin Raghuveer S. Murshed Johann
Zhang Liu Makala Chowdhury Alsmeier