Bilayer Plasma Oxidation for Low-Defect Polysilicon Oxide Films
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Solution Overview
Problem
Plasma processing techniques result in defects and impurities in oxide and polysilicon films due to hydrogen radicals, leading to increased surface roughness and reduced mechanical and electrical properties, which are difficult to remove.
Innovation Solution
A bilayer plasma oxidation process involving a barrier layer deposited over a polysilicon film, followed by an oxide layer, using specific ratios of radicals to prevent hydrogen diffusion and enhance conformality, thereby reducing defects and improving film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma processing techniques use reactants (oxygen and/or hydrogen) to improve the conformity of oxide films or polysilicon films, then film conformity is improved, but defects and impurities form in the films leading to increased surface roughness and reduced mechanical and electrical properties
Solution Approach 1:
The plasma processing is divided into two distinct stages: a first plasma process that forms the oxide or polysilicon film with good conformity, and a second plasma process that removes defects and impurities. This segmentation allows each process to be optimized independently - the first for conformity and the second for quality - thereby resolving the contradiction between film conformity and film quality.
Solution Approach 2:
The first plasma process is performed as a preliminary action to establish the base film with desired conformity. Then, a second plasma process is applied subsequently to remove the defects and impurities introduced during the first process. This sequential approach allows the preliminary film formation to focus on conformity while the subsequent treatment addresses quality issues.
2Productivity
If conventional plasma processing is used to deposit oxide films, then deposition can be achieved, but surface roughness increases and mechanical and electrical properties are reduced due to trapped defects and impurities
Solution Approach 1:
The process maintains continuous useful action by performing two plasma treatments in sequence without breaking the vacuum environment. The first plasma process deposits the film continuously, and the second plasma process continuously removes defects and impurities from the same film, ensuring that the beneficial deposition action is followed immediately by a corrective action that eliminates surface roughness and property degradation.
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 process reduces surface roughness, enhances mechanical and electrical properties, and increases deposition rates, resulting in improved film quality and reduced manufacturing costs.
Implementation Method 1
A barrier layer is formed over a surface of the substrate by introducing at least a first radical to the processing volume using a plasma source
Implementation Method 2
A barrier layer is formed over a surface of the substrate by introducing at least a first radical to the processing volume using a plasma source
Implementation Method 3
An oxide layer is formed on the barrier layer by introducing a combination of the first radical and a second radical to the processing volume using the plasma source
Implementation Method 4
An oxide layer is formed on the barrier layer by introducing a combination of the first radical and a second radical to the processing volume using the plasma source
Implementation Method 5
An oxide layer is formed on the barrier layer by introducing a combination of the first radical and a second radical to the processing volume using the plasma source
Data Source
AI summary
Embodiments of the present disclosure generally include apparatus and methods thereof of processing a substrate. The methods include receiving a substrate in a processing volume of a processing chamber. The processing volume is bounded by one or more interior side walls. A barrier layer is formed over a surface of the substrate by introducing at least a first radical to the processing volume using a plasma source. An oxide layer is formed on the barrier layer by introducing a combination of the first radical and a second radical to the processing volume using the plasma source. The combination of the first radical and the second radical includes a first ratio of the first radical to the second radical, in which the first ratio can include a ratio of about 95:5 of the first radical to the second radical to about 40:60 of the first radical to the second radical.