Dual-Frequency Plasma Etching for Selective Pattern Film Removal
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Solution Overview
Problem
Existing substrate processing methods face challenges in selectively removing thin films from pattern structures without damaging the substrate or reactor, particularly when high RF power is required to differentiate etch resistance between top and side surfaces, leading to potential damage and inefficiencies.
Innovation Solution
A substrate processing method that controls the etch rate by applying dual-frequency plasma, where high-frequency plasma increases the density of active species and low-frequency plasma enhances mobility, allowing for selective etching without excessively increasing RF power, thereby maintaining etch selectivity between top, bottom, and side surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high RF power is applied to differentiate etch resistance between top and side surfaces, then etch selectivity is improved, but substrate and reactor damage occurs
Solution Approach 1:
The plasma generation is segmented into two distinct frequency components: high-frequency plasma (e.g., 13.56 MHz) to increase active species density for etching, and low-frequency plasma (e.g., 400 kHz) to enhance active species mobility. This segmentation allows independent optimization of etch selectivity and damage prevention without requiring excessive total RF power.
Solution Approach 2:
The invention changes the parameter of plasma frequency from a single frequency to dual frequencies. By applying plasma at two different frequencies simultaneously or sequentially, the system achieves both high active species density (for etch selectivity) and high active species mobility (for uniform etching), thereby resolving the contradiction between etch selectivity and damage prevention.
2Manufacturing precision
If high RF power is applied to destroy SiN film on top surface, then etch resistance differentiation is improved, but lower film and reactor damage occurs
Solution Approach 1:
The plasma generation is segmented into two distinct frequency components: high-frequency plasma (e.g., 13.56 MHz) to increase active species density for etching, and low-frequency plasma (e.g., 400 kHz) to enhance active species mobility. This segmentation allows independent optimization of etch selectivity and damage prevention without requiring excessive total RF power.
Solution Approach 2:
The invention changes the parameter of plasma frequency from a single frequency to dual frequencies. By applying plasma at two different frequencies simultaneously or sequentially, the system achieves both high active species density (for etch selectivity) and high active species mobility (for uniform etching), thereby resolving the contradiction between etch selectivity and damage prevention.
3Strength
If RF power is increased to improve SiN film density and etch resistance, then film quality is improved, but excessive power causes film destruction and damage
Solution Approach 1:
The plasma generation is segmented into two distinct frequency components: high-frequency plasma (e.g., 13.56 MHz) to increase active species density for etching, and low-frequency plasma (e.g., 400 kHz) to enhance active species mobility. This segmentation allows independent optimization of etch selectivity and damage prevention without requiring excessive total RF power.
Solution Approach 2:
The invention changes the parameter of plasma frequency from a single frequency to dual frequencies. By applying plasma at two different frequencies simultaneously or sequentially, the system achieves both high active species density (for etch selectivity) and high active species mobility (for uniform etching), thereby resolving the contradiction between etch selectivity and damage prevention.
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 method enables selective removal of thin films on pattern structures without damaging the substrate or reactor, achieving desired etch selectivity and reducing the risk of damage associated with high RF power usage, while maintaining film integrity and process efficiency.
Implementation Method 1
generating active species by applying plasma
Implementation Method 2
due to an ion bombardment effect when RF power is applied, the SiN film formed on the top of the stepped structure may be made denser
Data Source
AI summary
A substrate processing method capable of preventing a damage to a reactor and a lower film includes: supplying a substrate having a pattern structure; forming a layer on the pattern structure; generating active species by applying plasma on the substrate; and selectively etching a layer on the pattern structure generated by the active species by performing isotropic etching on the layer, wherein the applying of the plasma includes: increasing a density of the active species; and increasing a mobility of the active species.