Method of making a vertical NAND device using sequential etching of multilayer stacks

US8946023B2 · kind B2 · utility

Assignee

• Sandisk Technologies, Inc. · US

Inventors

• Raghuveer S. Makala · Campbell, US
• Yao-Sheng Lee · Tampa, US
• Jayavel Pachamuthu · Milpitas, US
• Johann Alsmeier · San Jose, US
• Henry Chien · San Jose, US

Key dates

• Filing date: Jul 2, 2013
• Grant date: Feb 3, 2015
• Expiry date: Jul 2, 2033

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B43/10

Abstract

A method of making a vertical NAND device includes forming a lower portion of a memory stack over a substrate, forming a lower portion of memory openings in the lower portion of the memory stack, and at least partially filling the lower portion of the memory openings with a sacrificial material. The method also includes forming an upper portion of the memory stack over the lower portion of the memory stack and over the sacrificial material, forming an upper portion of the memory openings in the upper portion of the memory stack to expose the sacrificial material in the lower portion of the memory openings, removing the sacrificial material to connect the lower portion of the memory openings with a respective upper portion of the memory openings to form continuous memory openings, and forming a semiconductor channel in each continuous memory opening.