3D Memory Hole and Groove Etching for Uniform Channel Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing number of electrode layers in three-dimensional memory devices leads to higher aspect ratios of holes and grooves, making processing difficult and requiring advanced techniques to maintain symmetry and uniformity in hole formation.
Innovation Solution
Simultaneously forming first and second holes in a stacked body, connecting second holes to form grooves, and applying a charge storage film on the sidewalls of first holes, while using specific etching methods to maintain symmetry and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of electrode layers stacked increases to increase storage capacity, then the storage capacity is improved, but the aspect ratio of holes and grooves increases making processing more difficult
Solution Approach 1:
The stacked body is divided into alternating first layers and second layers, with holes formed through specific layers and grooves formed between holes. This segmentation allows independent processing of holes and grooves, reducing the overall processing difficulty while maintaining high storage capacity through the multi-layer structure.
Solution Approach 2:
The invention transitions from forming only vertical holes to a three-dimensional structure combining vertical holes with horizontal grooves connecting them. This dimensional change creates a more efficient space utilization that increases storage capacity without proportionally increasing the aspect ratio challenges.
2Quantity of substance
If the aspect ratio of holes increases due to more electrode layers, then the storage capacity is improved, but the uniformity and symmetry of hole formation deteriorates
Solution Approach 1:
By segmenting the structure into alternating first and second layers with different hole formation processes, the invention maintains uniformity within each layer type while accommodating the overall increased aspect ratio through the distributed multi-layer architecture.
Solution Approach 2:
Different regions (first layers vs. second layers) have different hole formation characteristics, with holes in second layers being connected by grooves while holes in first layers remain isolated. This local differentiation maintains manufacturing precision by allowing optimized processing for each region's specific requirements.
3Ease of manufacture
If conventional etching methods are used for high aspect ratio holes, then the processing is simpler, but asymmetric erosion occurs reducing memory cell characteristics
Solution Approach 1:
The etching process is segmented into separate operations for first layers and second layers, with grooves formed to connect holes in second layers. This segmentation allows each etching operation to be optimized for its specific aspect ratio and geometry, preventing asymmetric erosion while maintaining processing feasibility.
Solution Approach 2:
Grooves act as intermediary structures that connect holes in second layers, providing a controlled pathway that mediates the etching process. This intermediary structure allows uniform material removal and prevents asymmetric erosion by distributing the etching stress across multiple controlled interfaces.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method facilitates the formation of high-quality memory holes with uniform dimensions and suppressed variations, reducing processing complexity and cost by avoiding asymmetric erosion and maintaining consistent memory cell characteristics.
Implementation Method 1
etching a portion between the second holes next to each other in the stacked body, and connecting at least two or more second holes to form a groove
Data Source
AI summary
According to one embodiment, a method for manufacturing a semiconductor memory device includes simultaneously forming a plurality of first holes and a plurality of second holes in a stacked body. The stacked body includes a plurality of first layers and a plurality of second layers. The method includes etching a portion between the second holes next to each other in the stacked body, and connecting at least two or more second holes to form a groove. The method includes forming a film including a charge storage film on a sidewall of the first holes. The method includes forming a channel film on a sidewall of the film including the charge storage film.