Memory Cell Spacer Air-Gap Structure for High-Density Fabrication
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Solution Overview
Problem
Current semiconductor memory devices face challenges in high integration due to the requirement for fine pattern lines, which necessitates expensive and complex exposure techniques, making it difficult to achieve reliable and cost-effective fabrication.
Innovation Solution
A semiconductor memory device design that includes a substrate with bit line structures, spacers, and landing pads, featuring an air gap between spacers, which allows for improved integration and reliability through a method involving the formation of sacrificial spacers and interlayer dielectric layers, enabling easier fabrication and reduced parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fine pattern lines are used for high integration, then integration density is improved, but fabrication complexity and cost increase due to expensive exposure techniques
Solution Approach 1:
The spacer structure is divided into multiple segments including first spacer, second spacer, and third spacer portions, each serving specific functions. This segmentation allows the structure to achieve high integration density while maintaining manufacturability through standardized fabrication processes for each segment.
Solution Approach 2:
The invention introduces vertical dimensionality by forming spacers that extend in the vertical direction from bit line structures, and creates air gaps between spacer portions. This three-dimensional approach enables higher integration density without requiring proportionally finer lateral pattern dimensions, thus avoiding the need for expensive exposure techniques.
2Quantity of substance
If fine pattern lines are used for high integration, then integration density is improved, but fabrication cost increases due to expensive exposure techniques
Solution Approach 1:
Sacrificial patterns are formed preliminarily to define the precise locations where air gaps will be created. These sacrificial patterns are subsequently removed to form the air gaps, enabling complex three-dimensional spacer structures to be fabricated using standard processes rather than requiring expensive specialized exposure techniques.
Solution Approach 2:
Sacrificial patterns serve as intermediary structures that facilitate the formation of air gaps. These temporary structures enable the creation of complex geometries through conventional fabrication processes, and are removed after serving their purpose, thereby reducing overall fabrication cost.
3Ease of manufacture
If traditional spacer structures are used, then fabrication is simpler, but parasitic capacitance increases reducing reliability
Solution Approach 1:
Air gaps are strategically introduced in specific locations between the first and second spacer portions, while other regions maintain continuous material structures. This localized modification reduces parasitic capacitance in critical areas where it most impacts reliability, while preserving the overall structural integrity and manufacturability of the device.
Data Source
AI summary
A semiconductor memory device may include a substrate, a bit line structure extending in one direction on the substrate, the bit line structure including a sidewall, a storage node contact on the sidewall of the bit line structure, first and second spacers between the sidewall of the bit line structure and the storage node contact, the first spacer separated from the second spacer by a space between the first spacer and the second spacer, an interlayer dielectric layer on the bit line structure, the interlayer dielectric layer including a bottom surface, a spacer capping pattern extending downward from the bottom surface of the interlayer dielectric layer toward the space between the first and second spacers, and a landing pad structure penetrating the interlayer dielectric layer, the landing pad structure coupled to the storage node contact.