CCE Probe Plasma Strike Step Detection
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Solution Overview
Problem
In plasma processing, the strike step duration is often arbitrary, leading to wasted time and potential substrate or chamber damage due to inefficient plasma ignition and stabilization detection, resulting in reduced throughput and premature degradation of chamber components.
Innovation Solution
A method using capacitively-coupled electrostatic (CCE) probes to monitor ion flux, electron temperature, and floating potential during the strike step, allowing for real-time detection of plasma ignition and stabilization, thereby optimizing the strike step duration and ensuring successful plasma characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-defined arbitrary strike step duration is used, then plasma ignition and stabilization are ensured, but unnecessary time is wasted and throughput is reduced
Solution Approach 1:
The patent employs real-time monitoring of plasma parameters (ion flux, electron temperature, floating potential) during the strike step to detect when plasma ignition and stabilization have actually occurred. This feedback mechanism allows the system to dynamically determine the optimal strike step duration rather than using a fixed arbitrary time, thereby eliminating wasted time while ensuring reliable plasma ignition.
Solution Approach 2:
The strike step duration is transformed from a static pre-defined value to a dynamic parameter that adapts based on real-time plasma conditions. By continuously monitoring plasma parameters and adjusting the strike step termination point based on actual plasma stabilization detection, the system optimizes the balance between reliability and productivity.
2Reliability
If a longer strike step duration is used, then plasma stabilization is ensured, but chamber components degrade prematurely and maintenance frequency increases
Solution Approach 1:
Real-time monitoring of plasma parameters provides feedback on actual plasma stabilization status, allowing the system to terminate the strike step as soon as stabilization is achieved. This prevents unnecessary extended exposure of chamber components to plasma, thereby reducing premature degradation and extending component lifespan while maintaining adequate plasma stabilization.
3Productivity
If real-time plasma detection is implemented, then strike step duration is optimized, but device complexity increases
Solution Approach 1:
The patent utilizes a multi-functional probe system (CCE probe) that simultaneously measures multiple plasma parameters (ion flux, electron temperature, floating potential) with a single device. This approach provides comprehensive plasma characterization needed for accurate strike step detection without requiring multiple separate measurement systems, thereby limiting the increase in device complexity.
4Ease of operation
If arbitrary strike step timing is used, then process simplicity is maintained, but substrate damage may occur due to premature etch initiation
Solution Approach 1:
The system uses real-time plasma parameter monitoring to provide feedback on actual plasma stabilization status before initiating the etch process. This ensures that the etch step only begins when plasma conditions are adequate, preventing substrate damage from premature etch initiation while maintaining relatively simple operation through automated detection and 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
This approach reduces unnecessary strike step time, enhances plasma processing efficiency, minimizes substrate and chamber damage, and improves overall system throughput by accurately determining when the plasma is stabilized, allowing for timely initiation of the etch process.
Implementation Method 1
capacitively-coupled electrostatic (CCE) probes to monitor ion flux, electron temperature, and floating potential
Implementation Method 2
capacitively-coupled electrostatic (CCE) probes
Implementation Method 3
applying a substantially high gas pressure within the processing chamber and maintaining a low radio frequency (RF) power within the processing chamber
Data Source
AI summary
A method for identifying a stabilized plasma within a processing chamber of a plasma processing system is provided. The method includes executing a strike step within the processing chamber to generate a plasma. The strike step includes applying a substantially high gas pressure within the processing chamber and maintaining a low radio frequency (RF) power within the processing chamber. The method also includes employing a probe head to collect a set of characteristic parameter measurements during the strike step, the probe head being on a surface of the processing chamber, wherein the surface is within close proximity to a substrate surface. The method further includes comparing the set of characteristic parameter measurements against a pre-defined range. If the set of characteristic parameter measurements is within the pre-defined range, the stabilized plasma exists.