Air isolation in high density non-volatile memory

摘要

Air gap isolation in non-volatile memory arrays and related fabrication processes are provided. Air gaps are formed at least partially in isolation regions between active areas of the substrate. The air gaps may further extend above the substrate surface between adjacent layer stack columns. A sacrificial material is formed at least partially in the isolation regions, followed by forming a dielectric liner. The sacrificial material is removed to define air gaps prior to forming the control gate layer and then etching it and the layer stack columns to form individual control gates and columns of non-volatile storage elements.

主权项

1. A method performed as part of fabricating non-volatile storage, comprising:
forming a plurality of layer stack columns overlying a plurality of active areas of a substrate, each active area having two vertical sidewalls and being separated from an adjacent active area by a plurality of isolation regions in the substrate; partially filling the isolation regions with a first insulating material; forming a sacrificial material over the first insulating material in each isolation region, the sacrificial material extending above a level of a surface of the substrate; forming a dielectric liner vertically along the vertical sidewalls of each layer stack column; removing the sacrificial material after forming the dielectric liner to define a plurality of bit line air gaps extending vertically from an upper surface of the first insulating material to at least the level of the surface of the substrate; forming an intermediate dielectric layer after removing the sacrificial material; and forming a control gate layer after forming the intermediate dielectric layer.