US 2024/0196610 A1 · THREE-DIMENSIONAL MEMORY DEVICE WITH DIELECTRIC FINS IN STAIRCASE REGION AND METHODS OF MAKING THEREOF

Abstract

A memory device is formed by forming an alternating stack of insulating layers and sacrificial material layers over a substrate, forming memory openings through the alternating stack, forming memory opening fill structures in the memory openings, forming an access trench through a portion of the alternating stack forming an access trench fill structure in the access cavity, and iteratively performing multiple instances of a unit processing sequence. Each instance of the unit processing sequence includes a vertical recess etch step that vertically recesses the access trench fill structure and an isotropic etch step that isotropically recesses the sacrificial material layers. A finned access cavity is formed after the multiple instances of the unit processing sequence. A finned dielectric support structure is formed in the finned access cavity, and the sacrificial material layers are replaced with electrically conductive layers.

Claims20

Dependent claims

A memory device, comprising:

an alternating stack of insulating layers and electrically conductive layers located over a substrate, the electrically conductive layers having different lateral extents in a contact region that decrease with a vertical distance from a top surface of the substrate;
memory openings vertically extending through the alternating stack and located in a memory array region in which each of the electrically conductive layers is present;
memory opening fill structures located in the memory openings and comprising a vertical semiconductor channel and a respective vertical stack of memory elements located at levels of the electrically conductive layers;
and
a finned dielectric support structure located in the contact region and comprising a dielectric wall portion that continuous vertically extends from the substrate at least to a horizontal plane including top surfaces of the memory opening fill structures, and further comprises dielectric fin structures that are located at levels of the electrically conductive layers and laterally protrude outward from the dielectric wall portion.

2 more elements

A method of forming a memory device, the method comprising:

forming an alternating stack of insulating layers and sacrificial material layers over a substrate;
forming memory openings through the alternating stack;
forming memory opening fill structures in the memory openings, wherein each of the memory opening fill structures comprises a respective vertical semiconductor channel and a vertical stack of memory elements;
forming an access trench through a portion of the alternating stack;
forming an access trench fill structure in the access cavity;
iteratively performing multiple instances of a unit processing sequence, wherein each instance of the unit processing sequence comprises a vertical recess etch step that vertically recesses the access trench fill structure and an isotropic etch step that isotropically recesses physically exposed portions of the sacrificial material layers around a cavity that overlies the access trench fill structure, whereby a finned access cavity is formed after the multiple instances of the unit processing sequence;
forming a finned dielectric support structure in the finned access cavity;
and
replacing the sacrificial material layers with electrically conductive layers.

6 more elements

Dependencies are inferred from the claim text.

Three-dimensional memory device with dielectric fins in staircase region and methods of making thereof

Life of this patent

Three-dimensional memory device with dielectric fins in staircase region and methods of making thereof

Life of this patent

Abstract

Claims20