Augmented Plasma Etching System with Semi-Barrier
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Solution Overview
Problem
In plasma-enhanced etching, the interdependencies among plasma characteristics and etch result parameters make it difficult to independently control chemical and physical properties, limiting precise control and process window in narrow-gap capacitively coupled plasma processing chambers.
Innovation Solution
An augmented plasma processing system with a secondary plasma generating region, separated from the primary plasma region by a semi-barrier, allows for independent control of secondary plasma properties, such as dissociation, to influence the primary plasma, decoupling control parameters and enabling more precise tuning of etch results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If RF power is increased to control polymerization degree, then chemical properties of plasma are controlled, but physical properties such as plasma density and ion flux are also affected
Solution Approach 1:
The plasma processing system is divided into two independent plasma sources: a first plasma source for generating ions and a second plasma source for generating radical species. This segmentation allows independent control of chemical properties (radical density) and physical properties (ion flux, plasma density) that were previously coupled in single-plasma systems.
Solution Approach 2:
A barrier layer is introduced as an intermediary between the two plasma sources. This barrier allows selective transmission of species: it permits radical species from the second plasma source to reach the substrate while blocking ions and electrons from the first plasma source, enabling independent control of chemical and physical plasma properties.
2Adaptability or versatility
If single plasma source is used, then system is simpler, but independent control of chemical and physical plasma properties is not achieved
Solution Approach 1:
The system uses two separate plasma sources instead of one, with each source optimized for a specific function: one for ion generation and another for radical species generation. This segmentation provides the adaptability to independently control chemical and physical plasma properties.
Solution Approach 2:
The barrier layer acts as a selective intermediary that enables the two-plasma system to function as an integrated but independently controllable unit. It allows the system to achieve versatility in plasma property control while maintaining a unified processing chamber structure.
3Manufacturing precision
If barrier layer is introduced to separate plasma sources, then species selectivity is improved, but chamber complexity increases
Solution Approach 1:
The barrier layer is positioned between the two plasma sources and the substrate, acting as a selective intermediary. It allows radical species to pass through to the substrate while blocking ions and electrons, achieving high species selectivity. The barrier can be implemented as a physical structure or a layer on the substrate, minimizing added complexity.
Solution Approach 2:
The barrier layer provides locally differentiated properties: it is permeable to radical species while being impermeable to ions and electrons. This local quality control allows selective species transmission at the barrier location without requiring complex modifications to the entire chamber structure.
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 allows for more independent adjustment of process results, reducing trade-offs and expanding process windows, enabling new substrate processing conditions and optimizing etch performance.
Implementation Method 1
a secondary plasma is generated from a secondary feed gas in a secondary plasma generating region
Implementation Method 2
the secondary feed gas is dissociated in the secondary plasma generating region to form chemically activated neutral species
Data Source
AI summary
Methods for etching a substrate in a plasma processing chamber having at least a primary plasma generating region and a secondary plasma generating region separated from said primary plasma generating region by a semi-barrier structure. The method includes generating a primary plasma from a primary feed gas in the primary plasma generating region. The method also includes generating a secondary plasma from a secondary feed gas in the secondary plasma generating region to enable at least some species from the secondary plasma to migrate into the primary plasma generating region. The method additionally includes etching the substrate with the primary plasma after the primary plasma has been augmented with migrated species from the secondary plasma.