Semiconductor Memory Spacer Structure with Void for Capacitance Reduction
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Solution Overview
Problem
The challenge in semiconductor device manufacturing lies in achieving high integration density while minimizing pattern size, which requires advanced photolithography techniques, making it difficult to integrate semiconductor devices effectively.
Innovation Solution
The semiconductor device design includes a substrate with active regions, word lines, bit line structures, and spacer structures featuring a first spacer, a second spacer with a void, and a third spacer, where the second spacer is taller than the void, reducing parasitic capacitance and enabling closer spacing of components for enhanced integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography technique is advanced to achieve smaller pattern size, then integration density is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The spacer structure is segmented into three distinct spacers (first, second, and third spacers) with different heights and materials. This segmentation allows each spacer to serve specific functions: the first and third spacers provide structural support, while the second spacer with void reduces parasitic capacitance. This multi-level segmentation enables precise control over capacitance without requiring advanced photolithography techniques.
Solution Approach 2:
The second spacer is designed with local quality differences through the incorporation of voids at specific locations. The voids are positioned strategically within the second spacer to reduce parasitic capacitance between the bit line structure and contact plugs. This localized modification allows capacitance reduction without changing the overall structure or requiring complex manufacturing processes.
2Productivity
If integration density is increased by reducing pattern size, then device functionality is improved, but parasitic capacitance increases
Solution Approach 1:
The second spacer incorporates voids (porous structure) within its body. These voids reduce the dielectric material volume between the bit line structure and contact plugs, thereby reducing parasitic capacitance. The porous structure allows the spacer to maintain mechanical support function while minimizing capacitive coupling, enabling higher integration density without the harmful effect of increased parasitic capacitance.
Solution Approach 2:
The spacer structure uses composite materials with different properties for different spacers. The first, second, and third spacers are formed from different materials selected to optimize specific functions. The second spacer, which contains voids, uses materials and结构设计 that balance mechanical support with capacitance reduction, creating a composite structure that addresses both integration density and parasitic capacitance requirements.
3Productivity
If components are spaced closer to enhance integration, then manufacturing efficiency is improved, but reliability decreases due to increased capacitance
Solution Approach 1:
Dielectric material is extracted from the second spacer to create voids. This removal of material reduces the parasitic capacitance between the bit line structure and contact plugs. By taking out the harmful dielectric material from specific locations, the structure maintains close spacing for high integration while removing the source of parasitic capacitance that would compromise reliability.
Solution Approach 2:
The second spacer is designed as a porous structure with voids distributed within it. This porous configuration reduces the effective dielectric constant and capacitance in the critical region between the bit line structure and contact plugs. The porous material allows close component spacing for manufacturing efficiency while maintaining reliability by reducing parasitic capacitance effects.
Data Source
AI summary
A semiconductor memory device includes a substrate including active regions, word lines in the substrate and each extending in a first direction parallel to an upper surface of the substrate, bit line structures connected to the active regions, respectively, and each extending in a second direction crossing the first direction, and spacer structures on sidewalls of respective ones of the bit line structures. Each of the spacer structures includes a first spacer, a second spacer, and a third spacer. The second spacer is disposed between the first spacer and the third spacer and includes a void defined by an inner surface of the second spacer. A height of the second spacer is greater than a height of the void.