Patent ID: 8445347

Claim:
A method of making a monolithic three dimensional NAND string, comprising: forming a stack of alternating layers of a first material and a second material over a substrate, wherein the first material comprises a conductive or semiconductor control gate material and wherein the second material comprises a first sacrificial material; etching the stack to form a back side opening in the stack; depositing a second sacrificial material in the back side opening; etching the stack to form a front side opening in the stack; selectively removing the second material through the front side opening to form first recesses; forming a first blocking dielectric in the first recesses to partially fill the first recesses; forming a plurality of spaced apart dummy layer segments separated from each other in remaining unfilled portions of the first recesses over the first blocking dielectric; forming a charge storage material layer over the first blocking dielectric in the front side opening; forming a tunnel dielectric layer over the charge storage material layer in the front side opening; forming a semiconductor channel layer over the tunnel dielectric layer in the front side opening; selectively removing the second sacrificial layer from the back side opening; selectively removing the plurality of dummy layer segments through the back side opening to expose the first recesses in the back side opening; selectively removing portions of the charge storage material layer through the back side opening and the first recesses to form a plurality of spaced apart charge storage segments; and forming a second blocking dielectric in the first recesses and between the spaced apart charge storage segments through the back side opening.