Reducing Flaking in ARC Layers for Semiconductor Lithography
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Summary
Problems
The patterning of dielectric materials in semiconductor devices using anti-reflective coating (ARC) layers faces challenges such as resist poisoning and increased defect rates due to nitrogen contamination, especially at shorter exposure wavelengths, which affects the yield and throughput of the lithography process.
Innovation solutions
Incorporating a substantially nitrogen-free cap layer and an intermediate adhesion layer with high adhesion properties within the ARC stack to reduce flaking during sputter etch processes, allowing for efficient patterning and reduced defect rates by providing an internal source of adhesion material.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If nitrogen-enriched silicon dioxide is used as ARC material to adjust optical characteristics, then the optical performance is improved, but the flaking tendency during sputter etch increases
Why choose this principle:
The ARC layer is segmented into multiple sub-layers with different nitrogen concentrations. The lower portion contains higher nitrogen content for optimal optical performance, while the upper portion has reduced nitrogen content to minimize flaking during sputter etch. This segmentation allows each layer to fulfill its specific function without compromising the other.
Principle concept:
If nitrogen-enriched silicon dioxide is used as ARC material to adjust optical characteristics, then the optical performance is improved, but the flaking tendency during sputter etch increases
Why choose this principle:
Different regions of the ARC layer are assigned different material compositions tailored to their specific functional requirements. The lower ARC layer near the resist interface has optimized nitrogen content for anti-reflective properties, while the upper ARC layer has modified composition to reduce adhesion to chamber walls and prevent flaking. This local quality variation resolves the contradiction between optical performance and reliability.
Application Domain
Data Source
AI summary:
Incorporating a substantially nitrogen-free cap layer and an intermediate adhesion layer with high adhesion properties within the ARC stack to reduce flaking during sputter etch processes, allowing for efficient patterning and reduced defect rates by providing an internal source of adhesion material.
Abstract
By incorporating a material exhibiting a high adhesion on chamber walls of a process chamber during sputter etching, the defect rate in a patterning sequence on the basis of an ARC layer may be significantly reduced, since the adhesion material may be reliably exposed during a sputter preclean process. The corresponding adhesion layer may be positioned within the ARC layer stack so as to be reliably consumed, at least partially, while nevertheless providing the required optical characteristics. Hence, a low defect rate in combination with a high process efficiency may be achieved.