Bit Line Spacer Structure With Air Gaps for Lower RC Delay
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Solution Overview
Problem
The challenge of short-circuiting between bit lines and increased resist-capacitor delay in semiconductor devices due to shrinking device size, leading to degraded performance in flash memory manufacturing.
Innovation Solution
A semiconductor device design featuring conductive units with spacer structures and air gaps, formed by a method involving a spacer stack layer patterning and a barrier layer to create air gaps between conductive units, using different materials for the spacer layers to enhance support and reduce capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device size is shrunk to improve integration density, then productivity and integration are improved, but short-circuiting between bit lines occurs and RC delay increases
Solution Approach 1:
The patent introduces a barrier layer as an intermediary substance between adjacent conductive units. This barrier layer includes an air gap that physically separates the conductive units, preventing direct contact and short-circuiting while allowing the devices to be closely spaced for high integration density.
Solution Approach 2:
The barrier layer is selectively formed only in specific locations between conductive units where short-circuiting risk exists. The air gap is localized at critical interfaces, providing targeted isolation without affecting the overall device structure or requiring universal modification of all conductive elements.
2Productivity
If device size is shrunk to improve integration density, then productivity is improved, but RC delay increases causing performance degradation
Solution Approach 1:
The air gap within the barrier layer acts as an intermediary that reduces capacitive coupling between adjacent conductive units. By introducing this low-dielectric constant region, the parasitic capacitance is minimized, thereby reducing RC delay and improving signal transmission speed despite reduced device dimensions.
3Reliability
If spacer structures with multiple layers are used to prevent short-circuiting, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential isolation function from the complex multi-layer spacer structure and consolidates it into a simpler barrier layer with an air gap. By removing unnecessary material layers and retaining only the critical air gap region, the design achieves reliable short-circuit prevention with reduced structural complexity and fewer manufacturing steps.
4Loss of time
If air gap is formed between conductive units to reduce capacitance, then RC delay is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The barrier layer structure is designed to self-form the air gap through controlled material removal or deposition processes. The air gap emerges naturally from the fabrication sequence without requiring precise direct patterning, allowing the system to self-organize the low-dielectric constant region and reducing the stringency of manufacturing precision requirements.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a substrate, conductive units, and a plurality of gaps. The conductive units are disposed on the substrate. Each conductive unit includes: a conductive structure and a pair of spacer structures. Each spacer structure comprises a first spacer layer disposed on the substrate, a second spacer layer disposed on the first spacer layer, and a third spacer layer disposed on the second spacer layer. The first spacer layer, the second spacer layer and the third spacer layer each comprise different materials. The conductive structure is disposed on the substrate. The spacer structures are disposed along both sides of the conductive structure. The gaps are disposed between each of the conductive units.