Pulsed Plasma Monitoring via High-Speed Optical Sampling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plasma etch processes in semiconductor manufacturing struggle to precisely control pulsed plasma conditions, leading to potential damage and variability in wafer etching, especially as technology nodes shrink, due to limited monitoring capabilities.
Innovation Solution
Implementing a high-speed optical sensor to monitor pulsed plasma emissions at sampling rates up to hundreds of KHz or MHz, allowing for detailed analysis of waveform characteristics such as pulsing frequency and duty cycle, and transmitting processed data to chamber control tools for real-time adjustments and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional OES measures mean optical emission with low sampling frequency (100 Hz to 10 s), then the signal to noise ratio is improved by averaging out noise over time, but the plasma response cannot be monitored precisely enough for pulsed plasma control
Solution Approach 1:
The patent changes the sampling frequency parameter from traditional low frequencies (100 Hz to 10 s) to high frequencies (100 kHz to 10 MHz), enabling precise monitoring of pulsed plasma response while maintaining signal quality through appropriate signal processing techniques
Solution Approach 2:
The system dynamically adapts to the pulsed plasma characteristics by sampling at frequencies much higher than the pulse rate, allowing real-time capture of the plasma response during each pulse cycle and enabling precise control adjustments
2Manufacturing precision
If high sampling frequency is used to capture pulsed plasma waveform details, then the plasma control precision is improved, but the data processing complexity and transmission burden increase
Solution Approach 1:
The patent extracts and transmits only the essential waveform characteristics (amplitude, period, duty cycle) rather than the complete raw data stream, reducing the information transmission burden while maintaining the necessary control precision
Solution Approach 2:
The signal processing and feature extraction are performed locally at the sensor before transmission to the control tool, pre-processing the data to reduce complexity and transmission requirements while preserving manufacturing precision
3Reliability
If traditional OES is used with low sampling frequency, then the system complexity is kept low, but thermal drift and sensor variations cannot be compensated for in real-time
Solution Approach 1:
The high-speed optical sensor provides real-time feedback on plasma conditions, enabling the control system to detect and compensate for thermal drift and sensor variations dynamically, improving process stability through continuous monitoring and adjustment
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
Enhances process stability and chamber matching by providing precise control over plasma conditions, reducing thermal drift and sensor variations, and enabling early fault detection and correction, thus improving semiconductor fabrication outcomes.
Implementation Method 1
Traditional Optical Emission Spectroscopy (OES) measures the mean optical emission from the plasma
Implementation Method 2
sampling the received light at a sampling rate much higher than a pulse rate of the pulsed plasma
Data Source
AI summary
Monitoring of a pulsed plasma is described using an optical sensor. In one example, the invention includes receiving light emitted by a pulsed plasma in a semiconductor plasma processing chamber, sampling the received light at a sampling rate higher than a pulse rate of the pulsed plasma, wherein the sampled light has a periodic amplitude waveform and the sampling rate is higher than the period of the amplitude waveform, accumulating multiple sampled waveforms to form a mean waveform, and transmitting characteristics of the mean waveform to a chamber control tool.