Semiconductor Memory Hole Structure for Straight Sidewall Formation
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Solution Overview
Problem
The increasing complexity and aspect ratios of holes and grooves in semiconductor memory devices with multiple electrode layers pose significant processing challenges, particularly in forming uniform and symmetrical memory holes with high storage capacity, leading to difficulties in maintaining the integrity and roundness of the memory cell structure.
Innovation Solution
A method involving the simultaneous formation of first and second holes in a stacked body with alternating layers, where the second holes are connected to form a groove, allowing for the deposition of a charge storage film and channel film on the sidewalls, and using etching techniques to maintain symmetry and perpendicularity, thereby reducing asymmetric erosion and enhancing the uniformity of the memory hole structure.
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:
A mandrel structure is formed preliminarily within the memory hole before depositing the charge storage film and channel film. This mandrel serves as a pre-prepared core that guides subsequent material deposition and maintains structural integrity during high-aspect-ratio formation, enabling the creation of memory holes with larger storage capacity without proportionally increasing processing difficulty.
Solution Approach 2:
The patent employs a nested structure where the mandrel is positioned inside the memory hole, which itself is surrounded by charge storage film and channel film layers. This nested arrangement allows multiple functional layers to be contained within the memory hole structure, effectively increasing storage capacity while maintaining a manageable external footprint and processing complexity.
2Quantity of substance
If the aspect ratio of holes and grooves increases to increase storage capacity, then the storage capacity is improved, but the degree of processing difficulty becomes larger
Solution Approach 1:
The mandrel is formed in advance within the memory hole structure, providing a pre-established reference framework that guides subsequent material deposition. This preliminary action ensures that charge storage film and channel film are deposited uniformly along the sidewalls, maintaining manufacturing precision even as the aspect ratio increases to accommodate higher storage capacity.
Solution Approach 2:
The mandrel acts as an intermediary structure that mediates between the memory hole formation process and the subsequent film deposition. It provides a physical template that ensures uniform spacing and positioning of materials, thereby maintaining manufacturing precision while enabling the memory hole to achieve the aspect ratio necessary for increased storage capacity.
3Device complexity
If holes and grooves with different kinds of materials are formed, then the structural complexity is improved, but the processing difficulty increases
Solution Approach 1:
The patent combines the formation of holes and grooves into a unified memory hole structure with integrated functional regions. Instead of separately forming holes and grooves with different materials, the memory hole encompasses both the mandrel core and the surrounding film layers, merging multiple structural elements into a single integrated formation process that reduces processing difficulty while maintaining the necessary structural complexity for high-capacity storage.
Solution Approach 2:
The memory hole structure serves multiple functions simultaneously: it contains the mandrel for structural support, accommodates charge storage film for data retention, and includes channel film for charge transport. This multi-functional design eliminates the need for separate holes and grooves with different materials, reducing processing steps while achieving the required structural complexity for high-capacity operation.
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 approach enables the formation of memory holes with straight sidewalls and controlled dimensions, improving the consistency of memory cell characteristics and reducing processing complexity, allowing for efficient manufacturing of high-capacity semiconductor memory devices.
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
Implementation Method 2
forming a film including a charge storage film on a sidewall of the first holes
Implementation Method 3
forming a channel film on a sidewall of the film including the charge storage film
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.