Non-volatile memory fabrication and isolation for composite charge storage structures

A method of fabricating non-volatile memory to avoid stringer formation, the method comprising:

• providing over a substrate a plurality of rows of a first charge storage layer;
• providing a plurality of rows of a sacrificial layer between rows of the first charge storage layer that are adjacent in a first direction;
• providing a second charge storage layer over the rows of the first charge storage layer and the rows of the sacrificial layer;
• etching the second charge storage layer, the rows of the first charge storage layer and the rows of the sacrificial layer to form stacks extending in the first direction direction, each stack including a portion of the second charge storage layer, a subset of a plurality of first charge storage regions formed from the first charge storage layer, and a subset of a plurality of sacrificial features formed from the sacrificial layer;
• etching the substrate to define a plurality of isolation trenches between stacks that are adjacent in a second direction;
• and
• etching each portion of the second charge storage layer to define a plurality of second charge storage regions for each stack.

A method of fabricating non-volatile memory, comprising:

• forming a plurality of sacrificial features over a substrate, the sacrificial features including an upper surface having a length in a column direction, each sacrificial feature separated from adjacent sacrificial features in the column direction by a space;
• forming portions of a first charge storage layer in the spaces between sacrificial features;
• forming a second charge storage layer over the plurality of sacrificial features and the portions of the first charge storage layer;
• etching the second charge storage layer into columns extending in the column direction;
• etching the portions of the first charge storage layer to form a plurality of first charge storage regions for a plurality of non-volatile storage elements;
• forming a plurality of isolation trenches in the substrate after etching the second charge storage layer and etching the portions of the first charge storage layer;
• and
• etching the columns of the second charge storage layer to form a plurality of second charge storage regions for the plurality of non-volatile storage elements.

A method of fabricating non-volatile memory, comprising:

• forming a plurality of sacrificial features over a substrate, the sacrificial features including an upper surface having a length in a column direction, each sacrificial feature separated from adjacent sacrificial features in the column direction by a space;
• forming portions of a first charge storage layer in the spaces between sacrificial features;
• forming a second charge storage layer over the plurality of sacrificial features and the portions of the first charge storage layer;
• etching the second charge storage layer into columns extending in the column direction;
• etching the portions of the first charge storage layer to form a plurality of first charge storage regions for a plurality of non-volatile storage elements;
• and
• etching the columns of the second charge storage layer to form a plurality of second charge storage regions for the plurality of non-volatile storage elements;
• wherein etching the second charge storage layer into columns and etching the portions of the first charge storage layer to form a plurality of first charge storage regions are performed using a single pattern.