Patent ID: 9397107
Filing Date: 2016-07-19
CPC Classification: H01L

Claim Text:
1. A method of making a three dimensional NAND string, comprising: providing a stack of alternating first material layers and second material layers over a substrate, wherein the first material layers comprise an insulating material and the second material layers comprise sacrificial layers; forming a front side opening in the stack; forming a tunnel dielectric in the front side opening; forming a semiconductor channel in the front side opening over the tunnel dielectric; forming a back side opening in the stack; selectively removing the second material layers through the back side opening to form back side recesses between adjacent first material layers; forming a metal charge storage layer in the back side opening and in the back side recesses; and forming discrete charge storage regions in the back side recesses by removing the metal charge storage layer from the back side opening and selectively recessing the metal charge storage layer in the back side recesses.