Memory Hole Circularity via Curvature-Dependent Etching
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Solution Overview
Problem
The challenge in manufacturing integrated circuit devices is the formation of high aspect ratio features, such as memory holes, which often results in low circularity and potential blockages, leading to electric field concentration and device failure due to the difficulty in selectively removing films and forming connections within these features.
Innovation Solution
A method involving the use of sacrifice films with controlled etching rates to improve the circularity of memory holes and contact holes, reducing roughness and preventing blockages by selectively processing areas with different curvature radii, thereby inhibiting electric field concentration and enhancing manufacturing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If high aspect ratio features are formed to increase storage density, then substrate area utilization is improved, but circularity of holes deteriorates and blockages occur
Solution Approach 1:
A sacrifice film is formed on the inner surface of the hole before the main etching process. This preliminary action allows selective removal of material from specific regions (such as the lower portion or upper portion) to improve circularity. The sacrifice film is then selectively removed through controlled etching, enabling precise shaping of the hole without affecting the overall high aspect ratio structure.
Solution Approach 2:
The sacrifice film is applied selectively to specific regions within the hole (e.g., lower portion, upper portion, or entire inner surface) depending on where circularity improvement is needed. This local application allows targeted modification of the hole shape in problematic areas while maintaining the high aspect ratio overall, addressing the circularity issue without compromising the density benefits.
2Area of stationary object
If high aspect ratio features are formed to increase storage density, then substrate area utilization is improved, but device reliability deteriorates due to electric field concentration
Solution Approach 1:
The sacrifice film is deposited on the inner surface before etching, creating a protective layer that prevents direct exposure of the hole walls to the etching process. This preliminary protection reduces roughness and prevents electric field concentration that would otherwise occur at sharp edges and irregular surfaces, thereby improving device reliability while maintaining high aspect ratio structures.
Solution Approach 2:
The sacrifice film acts as a cushioning layer that absorbs and distributes mechanical and electrical stresses within the high aspect ratio hole. By being present before the etching and forming processes, it prevents the development of stress concentration points that would lead to electric field concentration and device failure, thus cushioning against reliability issues in advance.
3Device complexity
If conventional etching methods are used on high aspect ratio structures, then manufacturing process is simple, but manufacturing precision deteriorates due to blockages
Solution Approach 1:
The sacrifice film is formed on the inner surface before the main etching process. This preliminary layer prevents blockages by maintaining open pathways during etching, allowing etchant access to the bottom of high aspect ratio holes. The process remains relatively simple as it adds only one additional deposition step, while significantly improving hole formation precision.
Solution Approach 2:
The sacrifice film serves as an intermediary layer between the hole walls and the etching environment. It mediates the etching process by preventing direct interaction that causes blockages, while still allowing controlled material removal. This intermediary layer enables precise hole formation in high aspect ratio structures without significantly complicating the manufacturing process.
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 circularity of memory and contact holes, reduces the risk of device failure by preventing electric field concentration and facilitating the formation of connections, while also reducing manufacturing complexities and costs.
Implementation Method 1
performing a second etching on the second film and the first film via the recessed section, wherein the performing of the second etching includes performing a third etching in a condition of an etching rate at a place smaller in curvature radius in the recessed section being lower than an etching rate at a place larger in curvature radius in the recessed section
Data Source
AI summary
According to one embodiment, a method is disclosed for manufacturing an integrated circuit device, the method can include forming a mask member on a first film, the mask member having a pattern, performing a first etching on the first film using the mask member as a mask to form a recessed section in the first film, forming a second film covering an inner side surface of the recessed section. The second film has a film thickness of preventing blockage of the recessed section, and performing a second etching on the second film and the first film via the recessed section. The performing of the second etching includes performing a third etching in a condition of an etching rate at a place smaller in curvature radius in the recessed section being lower than an etching rate at a place larger in curvature radius in the recessed section.