FLOATING GATE ULTRAHIGH DENSITY VERTICAL NAND FLASH MEMORY AND METHOD OF MAKING THEREOF
First Claim
1. A method of making a monolithic 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 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 blocking dielectric inside the back side recesses and the back side opening, the blocking dielectric having a clam shaped regions inside the back side recesses; and
forming a plurality of copper control gate electrodes in the respective clam shell shaped regions of the blocking dielectric in the back side recesses.
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Accused Products
Abstract
A method of making a monolithic three dimensional NAND string including providing a stack of alternating first material layers and second material layers over a substrate. The first material layers comprise an insulating material and the second material layers comprise sacrificial layers. The method also includes 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 and forming a blocking dielectric inside the back side recesses and the back side opening. The blocking dielectric has a clam shaped regions inside the back side recesses. The method also includes forming a plurality of copper control gate electrodes in the respective clam shell shaped regions of the blocking dielectric in the back side recesses.
58 Citations
34 Claims
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1. A method of making a monolithic three dimensional NAND string, comprising:
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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 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 blocking dielectric inside the back side recesses and the back side opening, the blocking dielectric having a clam shaped regions inside the back side recesses; and forming a plurality of copper control gate electrodes in the respective clam shell shaped regions of the blocking dielectric in the back side recesses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A monolithic three dimensional NAND string, comprising:
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a semiconductor channel, at least one end portion of the semiconductor channel extending substantially perpendicular to a major surface of a substrate; a plurality of control gate electrodes extending substantially parallel to the major surface of the substrate, wherein the plurality of control gate electrodes comprise at least a first control gate electrode located in a first device level and a second control gate electrode located in a second device level located over the major surface of the substrate and below the first device level; a blocking dielectric located over the plurality of control gates; a tunnel dielectric in contact with the semiconductor channel; and at least one charge storage region located between the blocking dielectric and the tunnel dielectric; wherein each control gate comprises copper. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method of making a monolithic three dimensional NAND string, comprising:
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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 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 blocking dielectric inside the back side recesses and the back side opening, the blocking dielectric having a clam shaped regions inside the back side recesses; forming a first barrier layer over the blocking dielectric inside the back side recesses and the back side opening, the first barrier layer having clam shaped regions inside the clam shaped regions in the blocking dielectric the back side recesses; forming a plurality of first control gate layers in the respective clam shell shaped regions of the first barrier layer in the back side recesses; selectively recessing the first control gate layers and the first barrier layers in the back side recesses; and forming a plurality of second control gate layers in the respective clam shell shaped regions of the blocking dielectric in the back side recesses. - View Dependent Claims (29)
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30. A method of making a monolithic three dimensional NAND string, comprising:
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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 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 blocking dielectric inside the back side recesses and the back side opening, the blocking dielectric having a clam shaped regions inside the back side recesses; forming a first barrier layer over the blocking dielectric inside the back side recesses and the back side opening, the first barrier layer having clam shaped regions inside the clam shaped regions in the blocking dielectric the back side recesses; forming a second barrier layer over the first barrier layer in the back side opening and the back side recesses, the second barrier layer having clam shaped regions inside the clam shaped first barrier layer; selectively removing the first and second barrier layers from the back side opening; selectively, partially recessing the second barrier layer in the back side recesses to expose a portion of the clam shaped regions of the first barrier layer adjacent to the back side opening; and forming a plurality of control gate layers in the respective clam shell shaped regions of the first and second barrier layers in the back side recesses. - View Dependent Claims (31, 32, 33, 34)
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Specification