3D Memory Contact Plug Structure for Reliable Interconnects
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Solution Overview
Problem
There is a need for semiconductor devices with increased data storage capacity and improved reliability in data storage systems.
Innovation Solution
The semiconductor device incorporates a specific structure with contact plugs and spacer layers made of different materials, featuring varying widths along their length to enhance electrical connectivity and reliability, including a substrate, circuit devices, lower interconnection lines, and a peripheral region insulating layer, with spacer layers distinct from the insulating layer material, and contact plugs connected to lower interconnection lines through gate electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact plugs are made with uniform width, then manufacturing is simpler, but electrical connection reliability is reduced
Solution Approach 1:
The contact plug employs a non-uniform width design where the upper portion has a different width than the lower portion. This local variation optimizes electrical connection properties at different levels: the upper width ensures proper alignment with gate electrodes, while the lower width provides stable connection to interconnection lines, thereby improving overall electrical connection reliability without requiring complete structural redesign
Solution Approach 2:
The contact plug is divided into distinct segments with different widths - an upper portion and a lower portion. This segmentation allows each portion to be optimized for its specific function: the upper portion interfaces with gate electrodes requiring precise alignment, while the lower portion connects to interconnection lines requiring stable electrical contact, thus resolving the reliability-complexity contradiction
2Reliability
If spacer layers use the same material as peripheral region insulating layer, then manufacturing process is simpler, but electrical isolation performance is reduced
Solution Approach 1:
The spacer layer is formed from a different material than the peripheral region insulating layer, creating local material quality differentiation. This enables the spacer layer to provide enhanced electrical isolation specifically where needed between contact plugs and source structures, while the peripheral insulating layer maintains its own optimization for regional isolation, achieving superior overall electrical isolation performance
Solution Approach 2:
The device employs composite material construction with at least two different insulating materials: one for the spacer layer and another for the peripheral region insulating layer. This composite approach allows each material to be selected for its specific electrical isolation properties, optimizing the overall isolation performance while maintaining manufacturability through established multi-material fabrication processes
3Reliability
If contact plugs have larger width throughout, then electrical connection is more robust, but alignment with gate electrodes becomes more difficult
Solution Approach 1:
The contact plug width is locally optimized with different dimensions at different heights. The upper portion has a width optimized for alignment with gate electrodes, ensuring manufacturing precision, while the lower portion has a larger width that provides robust electrical connection to interconnection lines, thus resolving the contradiction between connection robustness and alignment precision
Data Source
AI summary
A semiconductor device includes a substrate, circuit devices on the substrate, lower interconnection lines electrically connected to the circuit devices, a peripheral region insulating layer covering the lower interconnection lines, a source structure on the peripheral region insulating layer, gate electrodes stacked and spaced apart from each other in a first direction on the source structure, channel structures penetrating through the gate electrodes and each including a channel layer, contact plugs penetrating through the gate electrodes and the source structure, extending in the first direction, and connected to a portion of the lower interconnection lines, and spacer layers between the contact plugs and the source structure and including a material different from a material of the insulating layer in the peripheral region, wherein each of the spacer layers has a first width on an upper surface and has a second width greater than the first width on a lower surface.