A method for forming a stair-step structure in a stack on a substrate is provided. The method comprises at least one stair step cycle. Each stair step cycle comprises trimming the mask and etching the stack. Etching the stack is provided in a plurality of cycles wherein each cycle comprises etching a SiO.sub.2 layer and etching a SiN layer. Etching a SiO.sub.2 layer comprises flowing a SiO.sub.2 etching gas into the plasma processing chamber, wherein the SiO.sub.2 etching gas comprises a hydrofluorocarbon, an inert bombardment gas, and at least one of SF.sub.6 and NF.sub.3, generating a plasma from the SiO.sub.2 etching gas, providing a bias, and stopping the SiO.sub.2 layer etch. The etching a SiN layer comprises flowing a SiN etching gas into the plasma processing chamber, comprising a hydrofluorocarbon and oxygen, generating a plasma from the SiN etching gas, providing a bias, and stopping the SiN layer etch.

Semiconductor memory devices may include a cell substrate including a cell array region, first and second extension regions and a through region, a first mold structure including first gate electrodes stacked in a stepwise manner, a first interlayer insulating layer extending conformally on the first gate electrodes on the second extension region, a second interlayer insulating layer on the first interlayer insulating layer, a second mold structure including second gate electrodes on the second interlayer insulating layer and stacked on the first extension region in the stepwise manner, a channel structure in the first and second mold structures on the cell array region, a first cell contact structure in the first mold structure on the second extension region, and a second cell contact structure in the first and second mold structures on the first extension region. The first and second interlayer insulating layers may have different impurity concentrations.

A method used in forming integrated circuitry comprises forming a stack comprising vertically-alternating first tiers and second tiers. The stack comprises a cavity therein that comprises a stair-step structure. Sidewalls of the cavity and steps of the stair-step structure are lined with an insulator material. Insulative material is formed in the cavity radially inward of the insulator material. An upper portion of the insulative material is removed from the cavity to leave the insulative material in a bottom of the cavity over the stair-step structure. After the removing, insulating material is formed in the cavity above the insulative material. Other embodiments, including structure independent of method, are disclosed.

An apparatus includes: a substrate; a plurality of pillar-shaped bottom electrodes provided over the substrate; and an upper electrode covering side and top surfaces of the pillar-shaped bottom electrodes with an intervening capacitor insulating film therebetween; wherein the pillar-shaped bottom electrodes have at least an upper portion and a lower portion, and the diameter of the upper portion is smaller than the diameter of the lower portion.

A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate, memory stack structures vertically extending through the alternating stack, etch stop plates located in the staircase region, laterally and vertically spaced apart among one another, and overlying an end portion of a respective one of the electrically conductive layers, and contact via structures located in a staircase region, vertically extending through a respective one of the etch stop plates, and contacting a respective one of the electrically conductive layers.

A semiconductor storage device includes a base body, a stacked body, a plurality of columns, and a plurality of first contacts. The base body includes a substrate, a semiconductor element on the substrate, a lower wiring layer above the semiconductor element in a thickness direction of the base body and connected to the semiconductor element, and a lower conductive layer above the lower wiring layer in the thickness direction. The stacked body is above the lower conductive layer and including an alternating stack of conductive layers and insulating layers. Each of the columns includes a semiconductor body extending through the stacked body and electrically connected to the lower conductive layer. The plurality of first contacts extend through the stacked body and electrically connected to the lower conductive layer. The lower conductive layer is separately provided under each of the plurality of first contacts.

A semiconductor storage device includes a base body, a stacked body, a plurality of columns, and a plurality of first contacts. The base body includes a substrate, a semiconductor element on the substrate, a lower wiring layer above the semiconductor element in a thickness direction of the base body and connected to the semiconductor element, and a lower conductive layer above the lower wiring layer in the thickness direction. The stacked body is above the lower conductive layer and including an alternating stack of conductive layers and insulating layers. Each of the columns includes a semiconductor body extending through the stacked body and electrically connected to the lower conductive layer. The plurality of first contacts extend through the stacked body and electrically connected to the lower conductive layer. The lower conductive layer is separately provided under each of the plurality of first contacts.

A semiconductor memory device and method of making the same are disclosed. The semiconductor memory device includes a substrate that includes a memory region and a peripheral region, a transistor including a metal gate located in the peripheral region, a composite dielectric film structure located over the metal gate of the transistor, the composite dielectric film structure including a first dielectric layer and a second dielectric layer over the first dielectric layer, where the second dielectric layer has a greater density than a density of the first dielectric layer, and at least one memory cell located in the memory region. The composite dielectric film structure provides enhanced protection of the metal gate against etching damage and thereby improves device performance.

A semiconductor memory device and method of making the same are disclosed. The semiconductor memory device includes a substrate that includes a memory region and a peripheral region, a transistor including a metal gate located in the peripheral region, a composite dielectric film structure located over the metal gate of the transistor, the composite dielectric film structure including a first dielectric layer and a second dielectric layer over the first dielectric layer, where the second dielectric layer has a greater density than a density of the first dielectric layer, and at least one memory cell located in the memory region. The composite dielectric film structure provides enhanced protection of the metal gate against etching damage and thereby improves device performance.

Memory circuitry comprising strings of memory cells comprises laterally-spaced memory blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers. Channel-material strings of memory cells extend through the insulative tiers and the conductive tiers in a memory-array region. The insulative tiers and the conductive tiers of the laterally-spaced memory blocks extend from the memory-array region into a stair-step region. Individual stairs in the stair-step region comprise one of the conductive tiers. Conductive vias are individually directly against conducting material that is in the one conductive tier in one of the individual stairs. Insulator material in the stair-step region is directly above the stairs. An insulative-material lining is circumferentially around and extends elevationally along individual of the conductive vias between the individual conductive vias and the insulator material. Individual of the insulative-material linings and the insulator material comprise an interface there-between. Other embodiments, including methods, are disclosed.