Staircase Insulating Layers for Etching Control in 3D Memory
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of semiconductor devices with three-dimensional memory cell arrays faces challenges in connecting contact plugs to conductive layers due to thickness differences in interlayer insulating films on staircase portions, leading to overetching and underetching issues, which complicates the process and increases costs.
Innovation Solution
A semiconductor device design featuring a stacked body with conductive and insulating layers, where a second insulating layer acts as an etching stopper and a third insulating layer is embedded between the conductive and insulating layers, allowing for uniform contact plug formation without additional lithography processes, thereby simplifying the manufacturing process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etching stopper film is formed on the staircase portion after forming the staircase pattern, then etching control is improved, but the manufacturing process becomes longer and costs increase due to additional lithography processes
Solution Approach 1:
The etching stopper film is formed in advance during the stacked body formation process, before the staircase pattern is created. This preliminary formation eliminates the need for subsequent lithography processes to add the stopper film, thereby reducing manufacturing complexity while maintaining etching control precision.
Solution Approach 2:
The formation of the etching stopper film is merged with the formation of the stacked body structure. By creating the stopper film as part of the initial layer stacking process rather than as a separate subsequent step, the manufacturing process is simplified and overall process time is reduced.
2Manufacturing precision
If the etching stopper film is formed along the staircase shape, then etching protection is provided, but the film protrudes to the contact region causing non-uniform thickness and connection difficulties
Solution Approach 1:
The etching stopper film is positioned selectively only on the upper surface of the insulating layer in the staircase portion, rather than conformally covering all surfaces. This localized placement provides etching protection where needed while preventing protrusion into the contact region, ensuring uniform contact region thickness and reliable connections.
Solution Approach 2:
The etching stopper film placement is segmented to be present only in specific locations (on the upper surface of the insulating layer) and absent in others (not on the side surfaces). This selective segmentation allows the film to provide protection without interfering with contact formation in critical regions.
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 solution enables reliable and efficient connection of contact plugs to conductive layers, preventing overetching and underetching, and streamlines the manufacturing process while maintaining cost-effectiveness.
Implementation Method 1
a second insulating layer different in material from the first insulating layer is provided on an upper surface of the first insulating layer of the staircase portion
Data Source
AI summary
A semiconductor device includes a stacked body including conductive layers and first insulating layers which are alternately stacked. The stacked body includes, on at least one side thereof, a staircase portion having stairs formed from the conductive layers and the first insulating layers. A second insulating layer different in material from the first insulating layer is provided on an upper surface of the first insulating layer of the staircase portion. The second insulating layer is away from the conductive layer on the same first insulating layer. A third insulating layer is provided on the staircase portion. Contacts are provided in the first, second, and third insulating layers situated in the respective stairs of the staircase portion. The contacts lead from an upper surface of the third insulating layer to the conductive layer under the first insulating layer.