Plasma Etching Cycle Using RF Power Modulation for Sidewall Protection
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Solution Overview
Problem
The existing gas switching method for substrate processing is inefficient due to the need for frequent gas replacement, leading to extended processing times and reduced throughput, while also causing damage to the side walls of etched holes during the dry etching process.
Innovation Solution
A substrate processing method that alternates between high and low dissociation plasma conditions using a specific radio-frequency power pattern to switch between etching and deposition steps, allowing for continuous processing without gas switching, thereby reducing damage and increasing etching speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas switching method is used to alternate between etching and deposition steps, then mask selectivity and vertical shape retention are improved, but processing time is extended and throughput is reduced
Solution Approach 1:
The patent changes the physical parameters of plasma (dissociation degree, ion density, electron temperature) by adjusting radio-frequency power conditions rather than switching gases. This allows transitioning between high-dissociation plasma (for etching) and low-dissociation plasma (for deposition) while maintaining the same gas composition, thereby eliminating gas switching time and improving throughput while preserving mask selectivity and vertical shape control.
Solution Approach 2:
The patent makes a single process gas serve multiple functions by controlling plasma conditions. The same fluorocarbon-based gas can produce either etching or deposition effects depending on the radio-frequency power parameters, eliminating the need for multiple gas systems and their associated switching mechanisms, thus reducing processing time while maintaining precision.
2Object-affected harmful factors
If gas switching method is used to alternate between etching and deposition steps, then side wall damage is reduced, but processing speed is decreased
Solution Approach 1:
The patent uses parameter changes in radio-frequency power to control plasma dissociation degree, enabling rapid transition between etching and deposition modes without gas switching delays. This maintains protective film formation on side walls during deposition phases while minimizing interruption to etching phases, thereby reducing side wall damage while maintaining high etching speed and productivity.
Solution Approach 2:
The patent maintains continuous plasma generation and continuous process gas flow throughout the cycle, eliminating the interruptions caused by gas switching. The useful actions of etching and deposition alternate continuously through plasma parameter modulation, ensuring no loss of time or productivity while still providing protective film formation to reduce side wall damage.
3Manufacturing precision
If frequent gas replacement is performed, then etching quality is improved, but processing efficiency is reduced
Solution Approach 1:
The patent achieves different etching and deposition qualities by changing plasma parameters (radio-frequency power, dissociation degree) rather than replacing gases. This maintains high etching quality through controlled high-dissociation plasma conditions while avoiding the productivity loss associated with frequent gas replacement, as the same gas can be rapidly reconfigured for different process modes.
Solution Approach 2:
The patent replaces the mechanical gas switching system with an electrical control system that modulates radio-frequency power parameters. This substitution eliminates the physical delays and complexities of gas valve operations, flow rate adjustments, and pressure equalization, thereby maintaining etching quality through precise plasma control while dramatically improving processing efficiency.
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 faster and less damaging etching with improved mask selectivity and vertical shape retention, while maintaining high etch rates and reducing the formation of scallops on the side walls.
Implementation Method 1
performing a plasma processing on the workpiece with first plasma generated from the process gas under a first plasma generation condition
Implementation Method 2
different from the first plasma generation condition in a radio-frequency condition and a processing time
Data Source
AI summary
A substrate processing method for a substrate processing device includes (a) supplying a process gas with specific conditions to a processing container having therein a stage on which a workpiece having an etching target film and a mask on the etching target film is placed, (b) performing a plasma processing on the workpiece with first plasma generated from the process gas under a first plasma generation condition, (c) performing a plasma processing on the workpiece with second plasma generated from the process gas under a second plasma generation condition that is different from the first plasma generation condition in a radio-frequency power condition and a processing time, and is the same as the first plasma generation condition in other conditions, and (d) repeating (b) and (c).