Semiconductor Contact Nitride Recess Integration Density
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Solution Overview
Problem
The challenge in semiconductor device fabrication is to increase integration density while overcoming the limitations of decreasing process margins in photolithography, which affects the realization of highly integrated semiconductor devices.
Innovation Solution
A semiconductor device design that includes a substrate with an active pattern delimited by a device isolation pattern, featuring a gate electrode, impurity regions, bit lines, contacts, and nitride patterns, where the nitride patterns are used to fill recess regions and isolate contacts, enhancing integration density and reducing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used for semiconductor device fabrication, then manufacturing capability is maintained, but integration density increases with decreasing process margins become difficult to realize
Solution Approach 1:
The patent introduces a vertical dimension by forming a recess region that extends downward from the surface, and placing a nitride pattern within this recess. This three-dimensional structure allows the nitride pattern to be positioned below the bit line level, effectively utilizing the vertical space to reduce parasitic capacitance without occupying additional lateral area, thus maintaining high integration density while improving device performance.
Solution Approach 2:
The nitride pattern acts as an intermediary element positioned between the first contact and the substrate. It serves as a barrier that prevents direct interaction between the conductive contact and the substrate, thereby reducing parasitic capacitance. The recess region serves as an intermediary space that accommodates the nitride pattern, allowing it to be positioned optimally for capacitance reduction while maintaining manufacturing feasibility.
2Manufacturing precision
If contact width is reduced to increase integration density, then more contacts can be packed, but parasitic capacitance increases
Solution Approach 1:
The patent moves the parasitic capacitance mitigation strategy from the lateral dimension to the vertical dimension. By placing the nitride pattern in a recess below the bit line level, it reduces the overlapping area between conductive elements in the vertical direction, thereby reducing parasitic capacitance without requiring larger lateral spacing between contacts.
Solution Approach 2:
The patent extracts the source of parasitic capacitance by removing material to form a recess region, and then filling part of it with a nitride pattern. This effectively takes out the problematic capacitance-forming region and replaces it with an insulating material, reducing parasitic capacitance while maintaining the compact contact structure needed for high integration density.
3Manufacturing precision
If more contacts are added to increase integration density, then device functionality improves, but unintentional oxidation increases
Solution Approach 1:
The nitride pattern serves as an intermediary protective layer between the contact and the ambient environment. Nitride materials are known for their oxidation resistance, and by positioning this pattern in the recess region adjacent to the contact, it acts as a barrier that prevents oxygen from reaching and oxidizing the contact material, thus protecting the increased number of contacts from unintentional oxidation.
Solution Approach 2:
The nitride pattern creates a locally inert environment around the contact by providing a barrier against oxygen exposure. This is analogous to protecting sensitive components in an inert atmosphere, where the nitride layer prevents oxidative reactions by blocking the diffusion of oxygen to the contact surface, thereby maintaining contact integrity in high-density configurations.
Data Source
AI summary
A semiconductor device may include a substrate including an active pattern delimited by a device isolation pattern, a gate electrode crossing the active pattern, a first impurity region and a second impurity region in the active pattern on both sides of the gate electrode, a bit line crossing the gate electrode, a first contact electrically connecting the first impurity region with the bit line, and a first nitride pattern on a lower side surface of the first contact. A width of the first contact measured perpendicular to an extending direction of the bit line may be substantially equal to that of the bit line.