Composite Hard Mask Patterning for High-Aspect-Ratio Etching
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Solution Overview
Problem
Current methods for manufacturing semiconductor devices face challenges in forming a hard mask with a pattern, particularly in maintaining mask thickness and achieving high etching selectivity and resistance as patterns miniaturize, leading to issues with dimensional accuracy and etching performance.
Innovation Solution
A pattern forming method involving the formation of a first mask layer and a second mask layer with a composite material containing organic and inorganic materials, where the second mask layer is oxidized using ozone to enhance etching selectivity and resistance, and the pattern is transferred to the first mask layer through etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hard mask is formed using conventional methods, then the mask can be created, but the mask thickness is reduced and etching selectivity deteriorates as patterns miniaturize
Solution Approach 1:
The patent applies composite materials by forming a mask layer containing both organic material and inorganic material. The organic material provides good pattern formation and etching selectivity, while the inorganic material contributes to mask thickness maintenance and etching resistance. This composite structure resolves the contradiction between achieving high-dimensional accuracy for miniaturized patterns and maintaining sufficient mask thickness and etching resistance.
Solution Approach 2:
The patent utilizes parameter changes by controlling the oxidation of the organic material component in the mask layer. By adjusting oxidation conditions, the organic material transforms into an oxidized state that enhances etching selectivity while maintaining mask integrity. This parameter control allows the mask to provide both high etching resistance and superior etching selectivity simultaneously.
2Manufacturing precision
If the mask layer is made thinner to accommodate miniaturized patterns, then pattern density increases, but etching selectivity and resistance decrease
Solution Approach 1:
The composite mask layer containing organic and inorganic materials enables pattern miniaturization while maintaining etching selectivity and resistance. The organic component ensures good pattern definition even at reduced dimensions, while the inorganic component provides the necessary thickness and etching resistance, resolving the trade-off between miniaturization and etching performance.
Solution Approach 2:
The mask layer exhibits local quality differentiation where the organic material primarily provides pattern formation capability and the inorganic material provides structural support and etching resistance. This functional differentiation allows the mask to achieve both miniaturized pattern accuracy and sufficient etching performance simultaneously.
3Reliability
If conventional etching masks are used, then the etching process can proceed, but dimensional accuracy deteriorates for high aspect ratio patterns
Solution Approach 1:
The composite mask layer with organic and inorganic materials provides superior dimensional accuracy for high aspect ratio patterns compared to conventional masks. The organic component ensures precise pattern transfer while the inorganic component maintains mask structural integrity during etching, preventing pattern distortion and achieving high dimensional accuracy alongside reliable etching performance.
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
This method allows for the easy formation of a hard mask with a desired thickness, improving etching selectivity, resistance, and dimensional accuracy, even for patterns with high aspect ratios, by controlling the oxidation and composition of the mask layers.
Implementation Method 1
oxidizing the inorganic material and removing at least a portion of the organic material from the second mask layer by exposing the second mask layer to a first oxidizing gas containing ozone
Data Source
AI summary
According to one embodiment, a pattern forming method includes: forming a first mask layer on a sample; forming a second mask layer on the first mask layer, the second mask layer containing a first inorganic material and a first organic material; forming a pattern in the second mask layer; oxidizing the first inorganic material and removing at least a portion of the first organic material from the second mask layer by exposing the second mask layer to a first oxidizing gas containing ozone; and transferring the pattern to the first mask layer by etching the first mask layer with the second mask layer.