Stepped Support Column Structure for 3D Memory Alignment
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Solution Overview
Problem
In three-dimensional semiconductor memory devices, the increasing complexity and miniaturization requirements pose challenges in maintaining the alignment and separation of conductive layers, leading to potential short-circuits and deteriorated memory cell characteristics due to manufacturing errors and processing variations.
Innovation Solution
The implementation of a semiconductor memory device structure with a stepped part and distinct heights for conductive layers and support columns, where the support column's height is lower than the contact's, ensuring sufficient distance and reduced area, thereby preventing short-circuits and improving current characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the device area is reduced for miniaturization, then integration level increases, but alignment precision between conductive layers deteriorates leading to potential short-circuits
Solution Approach 1:
A support column structure is introduced as an intermediary element between conductive layers. The support column has a top surface that provides a reference plane for forming contacts, ensuring proper alignment and separation between different conductive layers even when device dimensions are reduced. This mediator structure prevents direct contact between conductive layers while maintaining manufacturing precision.
Solution Approach 2:
The patent introduces a vertical dimension solution by using stepped parts with different heights. The support column extends to a first height, while the contact extends to a second height lower than the first height. This dimensional differentiation creates sufficient distance between conductive layers in the vertical direction, preventing short-circuits while allowing horizontal miniaturization.
2Reliability
If the distance between support columns and contacts is increased to prevent short-circuits, then reliability improves, but device area increases
Solution Approach 1:
Instead of increasing horizontal distance between support columns and contacts, the patent utilizes the vertical dimension by creating a stepped structure. The support column has a top surface at a first height, and the contact extends only to a second height lower than the first height. This vertical separation ensures sufficient distance for short-circuit prevention while maintaining compact horizontal dimensions for miniaturization.
3Productivity
If conductive layers are miniaturized to increase integration, then capacity increases, but manufacturing errors cause deteriorated memory cell characteristics
Solution Approach 1:
The support column acts as a mediator structure that provides a stable reference plane for contact formation. Even when conductive layers are miniaturized, the support column's top surface ensures consistent alignment and separation, reducing the impact of manufacturing errors on memory cell characteristics while maintaining high integration levels.
Solution Approach 2:
The stepped structure with the support column extending to a first height and the contact extending only to a second height provides a built-in safety margin before manufacturing variations can cause short-circuits. This beforehand cushioning in the vertical dimension protects against manufacturing errors while allowing horizontal miniaturization for increased integration.
Data Source
AI summary
A semiconductor memory device according to an embodiment comprises: a memory cell array region including a plurality of conductive layers that are electrically connected to a plurality of memory cells arranged in a first direction on a semiconductor substrate, the first direction intersecting a surface of the semiconductor substrate; a stepped part for contacting the plurality of conductive layers to a wiring line; a contact extending in the first direction and being connected to the conductive layer in the stepped part; and a plurality of columnar bodies extending in the first direction and penetrates the conductive layer in the stepped part and including a first columnar body having a first height and a second columnar body having a second height which is lower than the first height.