3D NAND Memory Pillar Etching via Segmented Support Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of three-dimensional NAND-type flash memory devices faces challenges in increasing reliability and manufacturing yield, particularly due to the difficulty in forming memory holes with high aspect ratios during the etching process, which can lead to structural instability and defects.
Innovation Solution
The semiconductor storage device employs a layered structure with alternating conductive and insulating films, where epitaxial growth layers and boron-doped regions are used to support the memory pillars and prevent damage during etching, allowing for the formation of memory and support pillars with reduced aspect ratios in separate etching steps, thereby enhancing structural integrity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If memory holes with high aspect ratios are formed during the etching process, then the capacity of three-dimensional NAND-type flash memory can be increased, but structural instability and defects occur leading to reduced reliability and manufacturing yield
Solution Approach 1:
The patent divides the formation process into separate etching steps: first forming memory holes with reduced aspect ratios, then forming support pillars, and finally forming additional memory holes. This segmentation avoids the structural instability caused by attempting to form all high-aspect-ratio features in a single etching step.
Solution Approach 2:
The patent performs preliminary actions by forming support pillars and insulation film patterns before forming the final memory holes. These preliminary structures provide mechanical support and prevent defects during subsequent processing steps, thereby improving reliability while enabling high-capacity three-dimensional stacking.
2Volume of moving object
If memory holes with high aspect ratios are formed during the etching process, then the capacity of three-dimensional NAND-type flash memory can be increased, but manufacturing yield decreases due to structural damage and defects
Solution Approach 1:
The manufacturing process is segmented into multiple controlled etching steps rather than attempting to form all high-aspect-ratio memory holes in one step. This reduces structural damage and defects, thereby improving manufacturing yield while still achieving the required memory capacity through three-dimensional stacking.
Solution Approach 2:
Support pillars and insulation film patterns are formed as preliminary structures before the final memory hole formation. These preliminary actions create a more robust structure that withstands subsequent processing, reducing yield loss from structural damage and defects.
3Productivity
If high-aspect-ratio memory holes are formed in a single etching step, then processing efficiency can be maintained, but insulating films may be damaged and structural integrity compromised
Solution Approach 1:
The etching process is segmented into multiple steps with intermediate formation of support structures. Although this increases the number of steps, each step operates under more favorable conditions with lower aspect ratios, reducing film damage and improving overall manufacturing precision while maintaining acceptable processing efficiency.
Solution Approach 2:
Insulation film patterns and support pillars are formed as preliminary structures before final memory hole etching. These preliminary actions protect the insulating films during subsequent processing, maintaining film integrity even though the overall process requires multiple steps.
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 improves the reliability and manufacturing yield of three-dimensional NAND-type flash memory devices by preventing structural damage and defects, enabling more efficient processing and maintaining the integrity of insulating films, even in high-aspect-ratio features.
Implementation Method 1
A first columnar body penetrates the first structural body in the first region and includes a first epitaxial layer on the semiconductor material end
Implementation Method 2
A portion of the second epitaxial growth layer is doped with boron
Data Source
AI summary
According to one embodiment, a semiconductor storage device includes a first structural body on a semiconductor material. The first structural body having a plurality of first conductive films and a plurality of first insulating films that are alternately stacked. A first columnar body penetrates the first structural body and includes a first epitaxial layer on an end adjacent to the semiconductor material. A second columnar body also penetrates the first structural body and includes a second epitaxial layer on an end adjacent to the semiconductor material. A portion of the second epitaxial layer is doped with boron.