Plasma Etching Radical Density Uniformity
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Solution Overview
Problem
The electrodeless plasma etching method struggles to achieve uniform radical density distribution, leading to non-uniform etching patterns, especially in the outer periphery of the sample, due to radical extinction on the inner wall of the decompression chamber and inadequate plasma generation in the sample's vicinity.
Innovation Solution
A plasma etching method where a first RF power is applied to generate plasma within the decompression chamber, and a second RF power of a higher frequency is used to create a plasma generation area in the outer periphery of the sample, with additive gas introduced through gas introduction holes positioned close to the sample to enhance radical distribution uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additive gas is introduced from the outer periphery of the sample, then radical generation is enhanced, but uniformity improvement is substantially ineffective
Solution Approach 1:
The patent divides the gas introduction system into multiple discrete gas introduction holes positioned at different locations (outer periphery, center, diagonal positions) relative to the sample. This segmentation allows independent control of plasma generation in different regions, enabling precise adjustment of radical distribution to achieve uniform etching across the entire sample surface.
Solution Approach 2:
The patent introduces additive gas through gas introduction holes positioned at specific locations (outer periphery, center, or diagonal positions) relative to the sample. This creates local plasma generation areas with different radical densities in different regions, allowing targeted compensation for radial concentration unevenness and achieving uniform radical distribution across the sample surface.
2Reliability
If electrodeless discharge system is used to prevent antenna electrode corrosion, then reliability is improved, but plasma uniformity deteriorates in the decompression chamber
Solution Approach 1:
The patent uses additive gas as an intermediary substance to mediate the plasma generation process. The additive gas is introduced into the decompression chamber and plasma-generated from it, creating radicals that serve as intermediaries to compensate for the non-uniform radical distribution caused by the electrodeless discharge system's inherent characteristics.
Solution Approach 2:
The patent changes the physical and chemical parameters of the plasma environment by introducing additive gas at controlled flow rates. This modifies the plasma generation characteristics, radical density distribution, and etching uniformity, allowing optimization of the electrodeless discharge system's performance without compromising its reliability advantages.
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 effectively increases oxygen radical density in the outer periphery, resulting in uniform etching patterns across the sample, improving the overall etching uniformity and reducing radial concentration unevenness.
Implementation Method 1
Electric field is supplied within to an upper portion of the decompression chamber from an outside of the decompression chamber and plasma is generated from the first gas inside the decompression chamber
Implementation Method 2
A first RF power of a first frequency... is supplied to the stage
Implementation Method 3
A second RF power of a second frequency which is higher than the first frequency and capable of generating plasma from the second gas above the stage that allows radicals generated in the plasma generated from the second gas to be supplied in the outer periphery
Implementation Method 4
A second RF power of a second frequency which is higher than the first frequency... is supplied to the stage
Implementation Method 5
ions are uniformized by diffusion
Data Source
AI summary
In the plasma etching method, a sample is placed on a stage in a chamber. A first gas is introduced into the chamber. Electric field is supplied within the chamber to plasma is generated from the first gas. A first RF power of a first frequency, which is for generating a bias voltage in the sample for etching the sample with radicals which are generated in the plasma while the plasma is generated, is supplied to the stage. A second gas is introduced from a position in outer periphery of a surface of the stage, on which the sample is placed. A second RF power of a second frequency higher than the first frequency and capable of generating plasma from the second gas above the stage that allows radicals generated in the plasma generated from the second gas to be supplied in the outer periphery, is supplied to the stage.