3D Memory Contact Plug Structure for Constant Width Connections
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Solution Overview
Problem
Existing memory devices with three-dimensional structures face challenges in maintaining a constant width for contact plugs connected to gate lines, which affects the reliability and performance of the memory device.
Innovation Solution
A memory device with a stack structure comprising alternately stacked conductive layers and interlayer insulating layers, featuring openings with protrusion portions that allow for the formation of contact plugs with a constant width, ensuring consistent electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional three-dimensional memory structures are used, then device integration is improved, but contact plug width consistency deteriorates
Solution Approach 1:
The patent introduces a protrusion portion in the opening that extends in the first direction (vertical dimension), creating a stepped structure. This dimensional change allows the opening to maintain a larger cross-sectional area at the contact plug formation region while connecting to upper conductive layers, thereby ensuring constant contact plug width without compromising the three-dimensional integrated structure.
Solution Approach 2:
The opening is designed with different cross-sectional areas at different positions: a larger cross-sectional area at the conductive layer contact portion and a smaller cross-sectional area at the upper portion. This local quality variation ensures that the contact plug maintains constant width where it contacts the conductive layer while still accommodating the three-dimensional stacked structure above.
2Reliability
If contact plug width is maintained constant, then resistance dispersion is reduced, but manufacturing complexity increases
Solution Approach 1:
The opening is segmented into distinct portions: a first opening portion extending from the conductive layer to the interlayer insulating layer, and a second opening portion extending from the interlayer insulating layer to the upper surface. The protrusion portion forms the boundary between these segments. This segmentation allows each portion to be optimized independently for its specific function while maintaining overall manufacturing feasibility.
Data Source
AI summary
A memory device may include a stack structure including a plurality of conductive layers and a plurality of interlayer insulating layers, which are alternately stacked along a first direction, an opening extending in the first direction from at least one conductive layer, among the plurality of conductive layers, in the stack structure, and a contact plug in the opening. The opening may include a protrusion portion protruding in a second direction intersecting the first direction.