Anisotropic Etching SiCN Multi-Color Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Achieving selective and anisotropic etch processes for materials like silicon carbon nitride (SiCN) in multi-color structures is challenging due to difficulties in achieving desired etch selectivity and edge placement accuracy.
Innovation Solution
The implementation of a cyclic surface modification and activation process using a high percentage of hydrogen and nitrogen trifluoride (NF3) in the process chemistry, which modifies the surface of SiCN and other materials, allowing for anisotropic etching with selectivity to adjacent materials in multi-color structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional etch chemistries are used on SiCN in multi-color structures, then the etch process can be performed, but the etch selectivity to adjacent materials is insufficient and anisotropy cannot be achieved
Solution Approach 1:
The etch process is divided into multiple discrete cycles, each consisting of a surface modification step followed by an activation step. This segmentation allows precise control over the etching mechanism, enabling selective removal of SiCN while preserving adjacent materials. The cyclic nature permits optimization of each individual step to achieve cumulative anisotropic etching with high selectivity.
Solution Approach 2:
The patent employs periodic cyclic etching where the process alternates between surface modification (using hydrogen-rich chemistry to terminate Si-C bonds) and activation (using fluorine-based chemistry to etch modified surfaces). This periodic action creates controlled, incremental material removal that accumulates to achieve the desired anisotropic profile with high selectivity to adjacent materials.
2Manufacturing precision
If multi-color material techniques are implemented, then feature size can be reduced beyond lithography limits, but achieving selective and anisotropic etches becomes particularly difficult
Solution Approach 1:
The surface modification step creates locally differentiated surface chemistry on the SiCN material, converting Si-C bonds to Si-H bonds in the exposed regions. This local chemical transformation enables selective subsequent etching of only the modified regions, allowing precise feature size control while managing the complexity of multi-color structures through localized chemical differentiation.
3Manufacturing precision
If cyclic surface modification and activation processes are used, then anisotropic etch with desired selectivity is achieved, but the number of cycles required increases process time
Solution Approach 1:
The cyclic etch process maintains continuous useful action by ensuring that each modification-activation cycle contributes incrementally to the overall anisotropic etch. The process parameters are optimized so that material removal is cumulative and controlled, with each cycle building upon the previous ones to achieve the target profile. This continuous progressive action balances precision with reasonable throughput by avoiding unnecessary intermediate steps.
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 approach enables anisotropic etching of SiCN and other materials with improved selectivity, achieving target etch amounts and profiles, overcoming the limitations of traditional etch chemistries that fail to achieve both anisotropy and selectivity.
Implementation Method 1
modifying a surface region of a first material within the adjacent lines to form a modified surface material
Implementation Method 2
activating the modified surface material to remove the modified surface material
Implementation Method 3
The cyclic etch achieves an anisotropic etch of the first material with selectivity to other materials within the adjacent lines
Data Source
AI summary
Embodiments provide anisotropic etch processes for silicon carbon nitride (SiCN) or other materials within multi-color structures with improved selectivity to materials in adjacent lines. Cyclic surface modification and activation processes are used to achieve an anisotropic etch with desired selectivity with respect to other materials in a multi-color structure. For example embodiments, selectivity of a first material, such as SiCN or silicon nitride, with respect to other materials in adjacent lines for the multi-color structure is achieved using the cyclic modification/activation processes. The materials within the multi-color structure can include, for example, silicon, silicon nitride, silicon carbon oxide, silicon oxide, titanium nitride, and/or other materials. For one embodiment, hydrogen is introduced to process chemistry to facilitate the surface modification. For one embodiment, a non-corrosive gas, such as nitrogen trifluoride, is included in the process chemistry with the hydrogen.