Plasma Etching Cycle for Mask Protection and Necking Control
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Solution Overview
Problem
Existing plasma processing methods face challenges in achieving selective etching of etching films while forming protective films on mask films, particularly in controlling the deposition and removal of these films to prevent necking and ensure efficient etching rates.
Innovation Solution
A plasma processing method involving multiple periods with varying flow rates of carbon-containing and oxygen-containing gases, along with adjustments in bias power, to etch and remove protective films on mask films, ensuring controlled etching and deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbon-containing gas is supplied at a high flow rate to form a protective film on the mask film, then the mask film is well protected, but the etching rate of the etching film decreases and necking occurs
Solution Approach 1:
The patent applies periodic action by dividing the plasma processing into multiple periods with alternating gas flow rates. In the first period, a high flow rate of carbon-containing gas forms a protective film on the mask film. In the second period, the flow rate is reduced to allow faster etching of the etching film. This periodic modulation resolves the contradiction by achieving both protective film formation and high etching rate at different time intervals.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the flow rate of the carbon-containing gas during the processing. The flow rate is changed from a first flow rate (higher) in the first period to a second flow rate (lower) in the second period. This dynamic adjustment allows the system to optimize between protective film formation and etching rate, preventing necking while maintaining productivity.
2Manufacturing precision
If the flow rate of carbon-containing gas is increased to prevent necking, then the protective film is maintained, but the etching precision and efficiency are reduced
Solution Approach 1:
The patent uses periodic action to alternate between high flow rate (for necking prevention and protective film maintenance) and low flow rate (for high etching efficiency). The first period maintains higher flow rate to prevent necking, while the second period reduces flow rate to maximize etching efficiency, achieving both precision and productivity goals.
Solution Approach 2:
The patent applies preliminary action by forming a sufficient protective film on the mask film in the first period before reducing the gas flow rate in the second period. This preliminary protective film formation ensures that when the flow rate is reduced for higher etching efficiency, the mask film remains protected and necking is prevented.
3Manufacturing precision
If multiple periods with varying flow rates are used to control protective film deposition and removal, then etching precision is improved, but the process complexity increases
Solution Approach 1:
The patent implements periodic action with a simple two-period cycle: first period with higher carbon-containing gas flow rate for protective film formation, and second period with lower flow rate for etching. This periodic modulation achieves high etching precision while keeping the process relatively simple and easy to control.
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 method effectively controls the etching process, preventing necking and enhancing etching rates by managing the flow rates and power levels of gases and bias signals, resulting in improved etching precision and efficiency.
Implementation Method 1
supplying into the chamber a processing gas including a carbon-containing gas to generate plasma from the processing gas to etch the etching film and to form a protective film on the mask film
Implementation Method 2
form a protective film on the mask film
Implementation Method 3
supplying the processing gas into the chamber to generate plasma from the processing gas to further etch the etching film and to remove at least part of the protective film
Implementation Method 4
etch the etching film
Data Source
AI summary
A plasma processing method executed by a plasma processing apparatus with a chamber is provided. The method includes (a) providing in the chamber a substrate that includes an etching film and a mask film, the substrate including a first region where the etching film is exposed and a second region where the mask film is exposed, (b) supplying into the chamber a processing gas including a carbon-containing gas to generate plasma from the processing gas to etch the etching film and to form a protective film on the mask film, and (c) supplying the processing gas into the chamber to generate plasma from the processing gas to further etch the etching film and to remove at least part of the protective film. (b) includes a first period and a second period, and a flow rate of the carbon-containing gas in the first period is greater than a flow rate of the carbon-containing gas in the second period, and (c) includes a third period and a fourth period, and a flow rate of the carbon-containing gas in the third period is less than the flow rate of the carbon-containing gas in the second period and a flow rate of the carbon-containing gas in the fourth period.