Air-Gap Cell Contact Structure for Lower Parasitic Capacitance
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, and reliability while reducing complexity, particularly due to increased parasitic capacitance issues.
Innovation Solution
The introduction of air gaps in the semiconductor device design, specifically through the formation of cell contact structures and bit line spacers, reduces parasitic capacitance by creating spaces within the dielectric layers, thereby enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor device dimensions are scaled down to improve computing ability, then device density and integration are improved, but parasitic capacitance increases and performance deteriorates
Solution Approach 1:
The patent introduces air gaps (porous structures) within the dielectric layers surrounding conductive features. These air gaps reduce the dielectric constant of the surrounding medium, thereby reducing parasitic capacitance between conductive elements. The air gaps are formed by removing sacrificial materials after conductive layer deposition, creating void spaces that lower the overall capacitance while maintaining device scaling benefits.
Solution Approach 2:
The patent extracts parasitic capacitance by removing dielectric material and replacing it with air gaps around conductive features. By taking out the solid dielectric material and replacing it with air (lower permittivity), the parasitic capacitance is reduced, allowing continued scaling without proportional performance degradation.
2Productivity
If device dimensions are reduced to increase integration, then device density improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming sacrificial layers before depositing conductive materials. The sacrificial layers are预先 placed in specific patterns, then conductive layers are deposited over them. Afterward, the sacrificial layers are selectively removed to create air gaps. This preliminary structuring simplifies the overall manufacturing process by enabling automated deposition followed by selective removal, rather than requiring complex direct patterning of air gaps.
Data Source
AI summary
The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a substrate; a drain positioned in the substrate; a top dielectric layer positioned on the substrate; a cell contact structure including a cell contact bottom conductive layer positioned in the top dielectric layer and on the drain, a cell contact top conductive layer positioned in the top dielectric layer and on the cell contact bottom conductive layer, and a cell contact top sealing layer positioned in the top dielectric layer, on the cell contact bottom conductive layer, and surrounding the cell contact top conductive layer; and a first air gap positioned in the top dielectric layer and surrounding the cell contact bottom conductive layer.