Self-Limited Etching of Organic Materials via Cyclic Plasma
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Solution Overview
Problem
The increasing complexity and aspect ratios in semiconductor integrated circuits require advanced etching processes that achieve selective etching and profile control, which existing plasma etching techniques struggle to meet effectively.
Innovation Solution
A method involving cyclic exposure of a substrate to alternating plasma-excited process gases containing hydrogen and noble gases to selectively etch organic materials relative to other materials, using a controlled plasma processing system with programmable logic for optimized etching parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching techniques are used, then the etching process can be performed, but selective etching and profile control become ineffective with increasing aspect ratios and complex materials
Solution Approach 1:
The patent applies periodic action by cycling between two different plasma chemistries: a first plasma chemistry that etches the organic material, and a second plasma chemistry that protects the organic material while etching the inorganic material. This periodic switching of plasma compositions enables selective etching of alternating layers in high aspect ratio structures, resolving the contradiction between maintaining etch selectivity and handling increased device complexity
Solution Approach 2:
The patent changes plasma process parameters by alternating between different gas compositions (first plasma chemistry vs. second plasma chemistry) with distinct etching characteristics. This parameter switching allows the same plasma etching system to achieve different selectivity profiles, enabling effective etching of complex multi-material structures with high aspect ratios
2Manufacturing precision
If conventional plasma etching techniques are used, then the etching process can be performed, but profile control becomes insufficient for high aspect ratio structures
Solution Approach 1:
By periodically alternating between plasma chemistries with different etching rates and selectivity characteristics, the process achieves superior profile control in high aspect ratio structures. The first plasma chemistry provides aggressive etching where needed, while the second plasma chemistry provides protection and smoothing, collectively achieving the required profile precision
Solution Approach 2:
The patent employs preliminary action by using the first plasma chemistry to pre-etch the organic material before introducing the second plasma chemistry. This sequential approach allows the process to establish the desired profile shape incrementally, achieving better control over final etch profiles in high aspect ratio features
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 precise and selective etching of organic materials, improving etch selectivity and profile control, thereby supporting the miniaturization and integration of semiconductor devices.
Implementation Method 1
forming a first plasma-excited process gas containing hydrogen (H) and optionally a noble gas element
Implementation Method 2
exposing the substrate to the first plasma-excited process gas... etch the first material selectively relative to the second material
Data Source
AI summary
A method and apparatus for selectively etching an organic material on a substrate is described. The method and apparatus includes forming a first plasma-excited process gas containing hydrogen (H) and optionally a noble gas element, exposing the substrate to the first plasma-excited process gas, forming a second plasma-excited process gas containing a noble gas element, exposing the substrate to the second plasma-excited process gas, and cyclically repeating the forming and exposing the first and second plasma-excited process gases at least two cycles to etch the first material selectively relative to the second material.