Etch-Stop Layers for Uniform 3D NAND Pillar Contacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Achieving uniform contact between vertically-extending channel material pillars and horizontal wiring in three-dimensional integrated memory assemblies is challenging, affecting the performance of memory arrays like 3D NAND memory devices.
Innovation Solution
Incorporating etch-stop materials such as magnesium, scandium, and yttrium elements along the bottom regions of channel material pillars, which facilitates the formation of uniform openings and ensures consistent contact with conductive structures, allowing for the fabrication of memory arrays with improved electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication methods are used to form openings to channel material pillars, then the fabrication process is simple, but the contact uniformity between channel material pillars and horizontal wiring deteriorates
Solution Approach 1:
The patent applies preliminary action by forming an etch-stop material layer before creating the openings. This etch-stop layer serves as a reference plane that ensures uniform opening depths across different locations, thereby achieving uniform contact between channel material pillars and horizontal wiring. The etch-stop material is deposited in advance to establish a consistent starting point for subsequent etching operations.
2Manufacturing precision
If openings are formed without etch-stop material, then the fabrication process is faster, but the depth consistency of openings deteriorates
Solution Approach 1:
The etch-stop material layer serves a self-service function by automatically providing a uniform depth reference for all openings. During the etching process, the etch-stop material self-regulates the opening depth, ensuring that all openings reach the channel material pillars at consistent depths without requiring complex external control mechanisms for each individual opening.
3Reliability
If etch-stop material is used along bottom regions of channel material pillars, then contact reliability improves, but material usage and process steps increase
Solution Approach 1:
The etch-stop material acts as an intermediary layer between the horizontal wiring and the channel material pillars. It provides a stable reference plane that mediates the formation of openings, ensuring that the openings penetrate to the correct depth and that the channel material pillars make uniform contact with the horizontal wiring, thereby improving electrical contact reliability.
Data Source
AI summary
Some embodiments include an assembly which has channel material pillars, and which has memory cells along the channel material pillars. A conductive structure is under the channel material pillars. The conductive structure has doped semiconductor material in direct contact with bottom regions of the channel material pillars. One or more of magnesium, scandium, yttrium and lanthanide elements is along the bottom regions of the channel material pillars. Some embodiments include methods of forming assemblies. A structure is formed, and a mass is formed against an upper surface of the structure. Plugs are formed within openings in the mass. The plugs comprise a second material over a first material. The first material includes one or more of magnesium, scandium, yttrium and lanthanide elements. Openings are formed to terminate on the first material, and are then extended through the first material. Channel material pillars are formed within the openings.