Plasma Emission Feedback Control for Stable Radical Density
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Solution Overview
Problem
Plasma processing in semiconductor manufacturing, particularly in periodic plasma processes like atomic layer etching, faces inefficiencies due to varying radical densities caused by non-constant emission intensity waveforms, leading to inconsistent process results.
Innovation Solution
A plasma processing method and apparatus that utilize a sensor to detect emission intensity within the chamber, calculate optimal processing conditions by adjusting gas flow rates and high-frequency power, and account for disturbances to maintain consistent radical densities through a state space model and predictive control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If periodic plasma processing is performed with gas supply and exhaustion repeated, then processing cycles can be completed, but radical density varies causing inconsistent process results
Solution Approach 1:
The patent employs optical emission spectroscopy (OES) to monitor plasma emission intensity in real-time during periodic plasma processing. The measured emission intensity serves as feedback to detect variations in radical density. Based on this feedback, the system dynamically adjusts processing parameters such as gas flow rates and high-frequency power levels to maintain consistent radical density across different processing steps, thereby resolving the contradiction between completing processing cycles and ensuring process consistency.
Solution Approach 2:
The patent changes processing parameters (gas flow rates, high-frequency power) based on detected emission intensity variations. By dynamically adjusting these parameters during the periodic processing cycles, the system maintains optimal radical density conditions for each step, ensuring consistent etching rates and film deposition quality while completing the full processing sequence.
2Stability of the object's composition
If gas flow rate is increased in initial period after switching, then gas supply stability improves, but system complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-defining gas flow rate profiles with higher flow rates during the initial period after gas supply switching. This preliminary high flow rate ensures rapid establishment of stable gas composition and radical density before the processing step begins, improving gas supply stability without requiring complex real-time control adjustments during the actual processing.
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 enhances process efficiency by stabilizing radical densities, improving the consistency and productivity of plasma processing, thereby optimizing the plasma processing conditions for better semiconductor manufacturing outcomes.
Implementation Method 1
emission intensity of radicals generated by ionization of the processing gas within the chamber is acquired by a sensor that detects emission intensity within the chamber
Implementation Method 2
emission intensity of radicals generated by ionization of the processing gas within the chamber
Data Source
AI summary
A plasma processing method includes (a) acquiring emission intensity of radicals generated by ionization of a processing gas within a chamber by a sensor that detects emission intensity within the chamber, in a plasma processing in which supplying of the processing gas to the chamber and exhausting of inside of the chamber are periodically repeated; (b) acquiring a target setting value of the emission intensity; and (c) calculating a processing condition of the plasma processing which brings the emission intensity closer to the setting value, based on the emission intensity acquired by (a) and the setting value acquired by (b).