Mask Layer Pre-Treatment for Etching Line Edge Roughness
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Solution Overview
Problem
The existing dry plasma etching processes using ballistic electron beams often result in line edge roughness (LER) and pattern abnormalities in the mask layer, which are transferred to the underlying layers, leading to reduced manufacturing yields and poor device performance due to initial exposure to atomic halogen species and energetic electrons.
Innovation Solution
Treating the mask layer with a pre-etching electron beam in the absence of atomic halogen species, followed by exposure to an oxygen-containing, halogen-containing, or noble gas plasma, or forming a protective layer to alter the mask layer and reduce LER, and then using a ballistic electron beam and etching plasma to transfer the pattern to the thin film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mask layer is exposed to atomic halogen species and energetic electrons during the etching process, then the etching process can proceed effectively, but line edge roughness and pattern abnormalities occur in the mask layer
Solution Approach 1:
The patent applies preliminary action by treating the mask layer with a pre-etching electron beam before the actual etching process. This pre-treatment modifies the mask layer properties in advance, making it more resistant to the harmful effects of atomic halogen species and energetic electrons during etching, thereby preventing line edge roughness while maintaining etching efficiency
Solution Approach 2:
The patent introduces an intermediary substance (oxygen-containing, halogen-containing, or noble gas plasma) that acts as a protective layer between the mask layer and the harmful etching environment. This intermediary layer shields the mask from direct exposure to atomic halogen species and energetic electrons, reducing line edge roughness while allowing the etching process to proceed
2Manufacturing precision
If the mask layer is treated to reduce line edge roughness, then manufacturing yield improves, but the etching process may be compromised
Solution Approach 1:
The patent applies parameter changes by carefully controlling the energy, duration, and intensity of the pre-etching electron beam treatment. By optimizing these parameters, the mask layer is modified sufficiently to reduce line edge roughness while maintaining its etch resistance and ensuring the etching process can still proceed effectively
Solution Approach 2:
The pre-etching treatment is designed to prepare the mask layer in advance with optimal properties for the subsequent etching process, ensuring both high pattern quality and maintained etching performance through careful parameter selection
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed method effectively reduces line edge roughness and pattern abnormalities, enhancing etch selectivity and manufacturing yields by altering the mask layer to be more resilient to the etching process without compromising the etching process's benefits.
Implementation Method 1
treating the mask layer with a pre-etching electron beam in the absence of an atomic halogen specie
Implementation Method 2
etching the thin film in a plasma processing system
Implementation Method 3
coupling direct current (DC) power to an electrode in the plasma processing system to form an etching electron beam to assist the etching plasma
Data Source
AI summary
A method of pre-treating a mask layer prior to etching an underlying thin film is described. A thin film, such as a dielectric film, is etched using plasma that is enhanced with a ballistic electron beam. In order to reduce the loss of pattern definition, such as line edge roughness effects, the mask layer is treated with an electron beam in the absence of an atomic halogen specie prior to proceeding with the etching process.