Multi-Input Optical Emission Spectroscope for Semiconductor Chamber Monitoring
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Solution Overview
Problem
In semiconductor fabrication, existing monitoring techniques for plasma etching processes lack efficient and cost-effective methods for simultaneously monitoring the status of multiple chambers, leading to potential under-cutting or over-cutting of features due to inaccurate endpoint detection, which increases the risk of device failure.
Innovation Solution
A chamber-status monitoring apparatus and method using a multi-input optical emission spectroscope with a time-division multiplexing scheme, where optical signals from multiple chambers are multiplexed and dispersed to measure spectrum information, allowing for simultaneous monitoring of multiple chambers without the need for calibration control, reducing measurement errors and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple optical emission spectroscopes are used to simultaneously monitor multiple chambers, then the measurement precision and reliability of endpoint detection is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines multiple optical emission spectroscopes into a single multi-input optical emission spectroscope that can simultaneously receive and analyze optical signals from multiple chambers. This merging approach maintains the measurement precision of individual spectroscopes while reducing device complexity and cost by using one instrument instead of multiple separate instruments.
Solution Approach 2:
The optical emission spectroscope is designed with multi-functionality to serve multiple chambers simultaneously. The device can process optical signals from different chambers through multiple input channels, making a single instrument capable of performing the endpoint detection function for all chambers without requiring separate dedicated spectroscopes for each chamber.
2Reliability
If multiple optical emission spectroscopes are deployed for simultaneous chamber monitoring, then the reliability of monitoring is improved, but the cost and ease of manufacture deteriorate
Solution Approach 1:
By merging multiple monitoring functions into a single optical emission spectroscope with multi-input capability, the patent reduces the total number of instruments required. This decreases manufacturing cost while maintaining monitoring reliability through the device's ability to simultaneously and independently analyze signals from multiple chambers.
Solution Approach 2:
The multi-input optical emission spectroscope provides universal monitoring capability across multiple chambers, allowing one device to perform the reliability-critical function of simultaneous chamber monitoring. This universal design reduces the overall system cost compared to deploying multiple separate spectroscopes while preserving the reliability benefits of simultaneous monitoring.
3Device complexity
If a single optical emission spectroscope is used to monitor multiple chambers, then the device complexity and cost are reduced, but measurement errors between chambers may increase
Solution Approach 1:
The optical emission spectroscope is designed with segmented processing channels, where each input channel corresponds to a specific chamber. This segmentation allows the device to independently process and analyze optical signals from different chambers without cross-interference, maintaining measurement precision and consistency across all chambers while using a single instrument.
Solution Approach 2:
Each input channel of the optical emission spectroscope is optimized with local quality characteristics specific to its corresponding chamber. The device can apply chamber-specific analysis parameters and calibration settings to each input channel, ensuring measurement precision is maintained for each individual chamber even though they are processed by a single instrument.
4Measurement precision
If calibration control is performed on the optical emission spectroscope according to chamber status changes, then the measurement precision is maintained, but the ease of operation and time consumption increase
Solution Approach 1:
The optical emission spectroscope incorporates self-service calibration capabilities that automatically adjust to chamber status changes without requiring manual intervention. The device can autonomously perform calibration routines based on detected chamber conditions, maintaining measurement precision while eliminating the operational burden and time consumption associated with manual calibration control.
Solution Approach 2:
The system implements feedback mechanisms where the optical emission spectroscope continuously monitors chamber status and automatically adjusts calibration parameters in response to detected changes. This feedback-driven calibration approach maintains spectrum measurement accuracy while simplifying operation, as the device self-regulates based on real-time chamber conditions without requiring operator involvement.
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 enables accurate and precise endpoint detection across multiple chambers, improving the quality and reliability of semiconductor fabrication by reducing measurement errors and costs associated with multiple optical emission spectroscopes.
Implementation Method 1
a multi-input optical emission spectroscope connected to the time-division multiplexer via a single optical fiber probe, the multi-input optical emission spectroscope being configured to receive the dispersed OTDM signal from the time-division multiplexer and to disperse the OTDM signal according to wavelengths to measure spectrum information
Implementation Method 2
a time-division multiplexer connected to each of the chambers via at least one respective optical fiber probe, the time-division multiplexer being configured to receive, via the at least one respective optical fiber probe, an optical signal from each chamber in accordance with corresponding plasma emission in the chamber
Implementation Method 3
an optical signal from each chamber in accordance with corresponding plasma emission in the chamber
Data Source
AI summary
A chamber-status monitoring apparatus includes a plurality of chambers, a time-division multiplexer configured to receive, via optical fiber probes, optical signals from each chamber, to divide each optical signal into first time slots having a predetermined duration, and to multiplex the first time slots to generate an OTDM signal, a multi-input optical emission spectroscope configured to receive and disperse the OTDM signal according to wavelengths to measure spectrum information, and a controller configured to divide the spectrum information of the dispersed OTDM signal into second time slots with a predetermined time interval therebetween, to classify the second time slots according to the chambers to obtain spectrum information of the optical signals of the individual chambers, and to control endpoint detection in each of the chambers in accordance with the spectrum information of the optical signal of the corresponding chamber.