Memory Staircase Recess Layout for Gate-Contact Electrical Isolation
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Solution Overview
Problem
Conventional memory devices often have insufficient dielectric material thickness in certain regions, leading to reduced reliability and performance due to the methods used in their formation, which affects the electrical separation between control gates and vertical conductive structures.
Innovation Solution
The formation of a staircase structure with dielectric portions in recesses between contact structures and control gates, along with the use of dielectric liners to enhance electrical separation, addresses the issue of insufficient dielectric thickness, thereby improving the reliability and performance of memory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional processes are used to form memory devices, then manufacturing simplicity is maintained, but dielectric material thickness becomes insufficient leading to reduced reliability
Solution Approach 1:
The dielectric structure is segmented into multiple portions: a first dielectric portion formed between the control gate and vertical conductive structure, and a second dielectric portion formed in a recess between contact structures and control gates. This segmentation allows each portion to be optimized independently for electrical separation while managing manufacturing complexity.
Solution Approach 2:
A recess is formed in the first dielectric material before forming the second dielectric portion. This preliminary action creates a structured interface that enables better control over dielectric thickness and electrical separation in critical regions where contact structures adjacent control gates.
2Reliability
If dielectric material thickness is increased to improve electrical separation, then reliability increases, but device dimensions and complexity increase
Solution Approach 1:
The dielectric structure has different qualities in different locations: the first dielectric portion provides baseline separation, while the second dielectric portion formed in the recess provides enhanced separation specifically in regions where contact structures are adjacent to control gates. This local quality enhancement improves reliability without uniformly increasing device complexity.
Solution Approach 2:
The solution moves from a single-layer dielectric approach to a multi-layer dielectric structure with vertical stacking. The first dielectric portion and second dielectric portion are arranged in different vertical levels, creating additional dimensional separation between conductive elements while managing overall device footprint.
3Manufacturing precision
If conventional dielectric formation is used, then manufacturing process is simple, but critical dimension control is difficult
Solution Approach 1:
The recess is formed in the first dielectric material before forming the second dielectric portion, creating a pre-defined geometric structure. This preliminary action establishes precise dimensional boundaries that guide subsequent material deposition, improving critical dimension control for the dielectric interface between contact structures and control gates.
Solution Approach 2:
The dielectric formation process is segmented into distinct steps: forming the first dielectric portion, forming the recess, and forming the second dielectric portion. This segmentation allows each step to be optimized for specific dimensional requirements, improving overall manufacturing precision while managing process complexity through systematic breakdown.
Data Source
AI summary
Some embodiments include apparatuses and methods of forming the apparatuses. One of the apparatuses includes tiers located one over another, the tiers including conductive materials that form part of respective control gates for memory cells of the apparatus; a staircase structure formed in the tiers, the conductive materials including respective portions that collectively form a part of the staircase structure, the staircase structure including a sidewall on a side of the staircase structure; a dielectric liner formed on the sidewall; recesses formed in respective tiers and adjacent the sidewall such that respective portions of the dielectric liner are located in the recesses; and a contact structure extending through a portion of the dielectric liner, wherein the portions of the dielectric liner are between the contract structure and the conductive materials.