U-Shaped Buried Plug Layer for Semiconductor Integration Density
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Solution Overview
Problem
The challenge in semiconductor memory devices is to overcome process difficulties caused by reduced critical dimensions and line widths, which affect integration density and performance.
Innovation Solution
A semiconductor structure is developed with a substrate, active areas, device isolation regions, bit line structures, a conductive diffusion area, and a buried plug layer with a U-shaped cross-sectional profile, along with a storage node contact layer, to enhance integration and performance by forming a contact hole and embedding the storage node contact layer within the buried plug layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If critical dimensions and line width are reduced to increase integration density, then integration density is improved, but process difficulty increases
Solution Approach 1:
The contact structure is segmented into multiple functional layers: a buried plug layer with U-shaped cross-section at the bottom, and a storage node contact layer above it. This segmentation allows each layer to be optimized independently - the buried plug layer provides mechanical support and electrical connection through the void, while the storage node contact layer provides the storage function, thereby reducing overall process difficulty while maintaining high integration density
Solution Approach 2:
The storage node contact layer is embedded within the contact hole that is surrounded by the buried plug layer. This nested configuration allows the storage node to be positioned precisely while the buried plug layer provides structural support and electrical connection, enabling high integration density without proportionally increasing process complexity
2Ease of manufacture
If conventional contact structures are used with reduced dimensions, then manufacturing is simpler, but dishing phenomena occur and contact reliability deteriorates
Solution Approach 1:
The buried plug layer is formed in advance at the bottom of the contact hole before the storage node contact layer is deposited. This preliminary action creates a reliable electrical connection path and structural support beforehand, preventing dishing phenomena and ensuring contact reliability before subsequent manufacturing steps are performed
Solution Approach 2:
The buried plug layer acts as an intermediary between the conductive diffusion region and the storage node contact layer. It provides a stable platform that ensures reliable electrical connection while preventing direct contact between the storage node and substrate, thereby eliminating dishing phenomena and improving contact reliability
Data Source
AI summary
A semiconductor structure includes an active area in a substrate, a device isolation region surrounding the active area, first and second bit line structures on the substrate, a conductive diffusion region in the active area between the first and the second bit line structures, and a contact hole between the first and the second bit line structures. The contact hole partially exposes the conductive diffusion region. A buried plug layer is disposed in the contact hole and in direct contact with the conductive diffusion region. A storage node contact layer is disposed on the buried plug layer within the contact hole. The storage node contact layer has a downwardly protruding portion surrounded by the buried plug layer. The buried plug layer has a U-shaped cross-sectional profile.