Pulsed Plasma Timing Control for Uniform Substrate Exposure
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Solution Overview
Problem
Conventional plasma processing systems face challenges in maintaining uniform plasma distribution and optimal plasma fields, leading to inconsistent product quality and reduced throughput, especially as substrate geometries shrink and processing requirements become more complex.
Innovation Solution
The system controls pulsed plasma by adjusting pulse timing parameters based on real-time measurement data, allowing for dynamic control of plasma exposure through feedforward or feedback mechanisms, thereby modifying pulse widths and timing to maintain specified plasma properties such as density and ion flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hardware and processing techniques are used to generate plasma, then plasma can be produced in the plasma process chamber, but non-uniform distribution of ions or plasma density across the substrate occurs
Solution Approach 1:
The system applies periodic pulsing of plasma source power and substrate bias power with different pulse widths to create controlled variations in plasma density and ion flux. By alternating between high-density plasma phases and low-density relaxation phases, the system achieves uniform ion distribution across the substrate while maintaining high overall plasma density
Solution Approach 2:
The system dynamically adjusts plasma parameters including source power pulse width, bias power pulse width, and pulse frequency based on real-time process conditions. This dynamic control enables adaptation to changing substrate geometries and process requirements, maintaining uniform plasma distribution throughout the processing sequence
2Ease of operation
If fixed plasma parameter settings are used, then the plasma processing system is simple to operate, but insufficient mechanisms for responsive control of plasma during the etch or deposition process sequence are provided
Solution Approach 1:
The system incorporates real-time measurement of plasma parameters such as optical emission spectroscopy signals and electrical parameters, using this feedback to dynamically adjust source power and bias power pulse widths. This closed-loop control provides responsive adaptation to process variations while maintaining ease of operation through automated control
Solution Approach 2:
The system changes multiple plasma parameters simultaneously including source power amplitude, bias power amplitude, source power pulse width, bias power pulse width, and pulse frequency. This multi-parameter control provides versatile responsive control capability while keeping the operator interface simple through integrated control algorithms
3Device complexity
If conventional systems are used, then the system architecture is straightforward, but sufficient plasma density cannot be achieved under certain processing conditions and/or with certain plasma gases
Solution Approach 1:
The system uses periodic pulsing of plasma source power with optimized pulse widths to achieve high peak plasma densities that would be difficult to sustain with continuous power application. The pulsed regime allows for higher instantaneous power delivery while maintaining system architecture simplicity
Solution Approach 2:
The system dynamically adjusts source power pulse width and frequency based on real-time plasma density measurements and process requirements. This dynamic adaptation enables achievement of sufficient plasma density under varying processing conditions including different gas chemistries while maintaining a straightforward system architecture
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 enhances the controllability of plasma processes, ensuring consistent and optimal plasma fields, which improves product quality and throughput by dynamically adjusting plasma parameters in response to changing substrate conditions and process variables.
Implementation Method 1
Plasma processing systems generate plasma by supplying high frequency electrical power to gas mixtures in a plasma process chamber to ionize the gases
Implementation Method 2
generating measurement data corresponding to the first power signal, the second power signal, the plasma and/or a chamber pressure
Data Source
AI summary
Various embodiments of systems and methods are described herein for controlling a pulsed plasma. Pulse timing parameters (e.g., the pulse on-time and/or the pulse-off time) of the plasma generation source may be controlled based on the measurement data received from measurement device(s), to control the plasma exposure of the substrate during a sequence of dynamically controlled pulses within the plasma process chamber. In addition or alternatively, pulse timing parameters (e.g., the pulse on-time and/or the pulse-off time) can be applied to the source power, bias power, and/or both based on the measurement data received from measurement device(s), to control a plasma exposure of the substrate. The pulse timing changes may be made in a feedforward or feedback manner.