CPC H10B 43/50 (2023.02) [H01L 21/76895 (2013.01); H01L 23/5226 (2013.01); H01L 24/05 (2013.01); H10B 41/10 (2023.02); H10B 41/27 (2023.02); H10B 41/50 (2023.02); H10B 43/10 (2023.02); H10B 43/27 (2023.02); H10B 43/35 (2023.02); H01L 2224/05009 (2013.01); H01L 2224/0557 (2013.01); H10B 41/35 (2023.02)] | 20 Claims |
1. A method for forming a three-dimensional (3D) NAND memory device, comprising:
forming an alternating dielectric stack comprising a plurality of dielectric layer pairs, each of the plurality of dielectric layer pairs comprising a first dielectric layer and a second dielectric layer different from the first dielectric layer;
forming a first staircase structure in the alternating dielectric stack;
forming a channel structure and a barrier structure each extending vertically through the alternating dielectric stack, wherein the barrier structure separates the alternating dielectric stack into a first portion surrounded by the barrier structure, and a second portion comprising the first staircase structure;
forming a slit;
replacing, through the slit, first dielectric layers in the second portion of the alternating dielectric stack with conductor layers to form an alternating conductor/dielectric stack comprising a plurality of conductor/dielectric layer pairs;
forming a slit structure by depositing a conductor in the slit;
forming a first contact layer comprising a plurality of first contacts, wherein the plurality of first contacts flush with one another at a respective first end of each of the first contacts;
forming a second contact layer comprising a plurality of second contacts, wherein the second contact layer is above and different from the first contact layer, wherein each of (i) a conductor layer of the alternating conductor/dielectric stack in the first staircase structure, (ii) the channel structure, and (iii) the slit structure is in contact with a respective second end of the plurality of first contacts, and wherein the plurality of second contacts flush with one another at a respective first end and a respective second end of each of the plurality of second contacts, wherein each of the plurality of second contacts is in contact with a respective one of the plurality of first contacts; and
forming an interconnect conductor layer above the second contact layer, wherein each of (i) a top conductor layer of the alternating conductor/dielectric stack in the first staircase structure, (ii) the channel structure, and (iii) the slit structure is connected to the interconnect conductor layer by a corresponding first contact and a respective one of the plurality of second contacts via a conducting material.
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