Multi-Axes Optical Detector for Plasma Chemical Species Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Plasma etching processes in semiconductor and display manufacturing face inconsistencies due to the averaging of local chemical species concentrations, which are crucial for processing outcomes, as current optical emission spectroscopy methods fail to spatially resolve emissions and absorptions effectively.
Innovation Solution
Implementing a multi-axes optical detector system that forms an intersecting grid to collect optical spectra from multiple angles, enabling computed tomographic techniques to localize and pinpoint chemical species distributions above the substrate, thereby providing a two-dimensional mapping of chemical species during plasma processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical emission spectra is acquired from a single elongated volume using conventional OES, then the measurement process is simple, but local variations of chemical species concentrations are lost due to averaging
Solution Approach 1:
The plasma processing chamber is divided into multiple discrete measurement zones along the substrate surface. Multiple optical detectors are positioned at different locations and angles to independently measure optical emission spectra from each zone, enabling spatially resolved chemical species concentration measurements without requiring a single complex scanning system
Solution Approach 2:
The measurement system transitions from a single-line-of-sight configuration to a multi-axes three-dimensional detector arrangement. By positioning detectors at various angles and heights above the substrate, the system captures optical emission data from multiple spatial dimensions, creating a comprehensive three-dimensional map of chemical species distributions that reveals local variations invisible to conventional single-axis OES
2Manufacturing precision
If multiple process variables are controlled to manage plasma chemistry, then plasma processing outcomes can be optimized, but the complexity of monitoring and controlling local chemical species distributions increases
Solution Approach 1:
The multi-axes optical detector system provides real-time spatially resolved measurements of chemical species concentrations across the plasma processing chamber. This detailed feedback information is fed back to the process control system, enabling dynamic adjustment of process variables (such as RF power, gas flow rates, and pressure) to maintain uniform plasma chemistry and consistent processing outcomes across the substrate surface
Solution Approach 2:
The optical detector system serves multiple functions simultaneously: it identifies chemical species present in the plasma, measures their spatial distributions, monitors temporal variations during processing, and provides diagnostic information for process optimization. This multi-functional capability reduces the need for separate measurement systems for each function, thereby managing overall system complexity while achieving precise manufacturing control
3Measurement precision
If conventional single-axis OES is used for process monitoring, then the system is easy to operate, but endpoint detection accuracy is reduced due to averaged signals
Solution Approach 1:
The endpoint detection process is segmented into multiple independent measurements across different spatial zones. Each optical detector monitors its local region independently, allowing the system to detect endpoint conditions (such as substrate clearing or film completion) at different locations separately. This segmentation enables accurate detection of local variations in processing progress that would be masked by averaging in conventional single-axis OES
Solution Approach 2:
The system adds spatial dimensionality to endpoint detection by distributing multiple detectors across the processing chamber. This three-dimensional monitoring approach captures spatial variations in chemical species concentrations that indicate local processing progress, enabling precise endpoint detection even when different regions of the substrate are at different stages of processing. The multi-axes configuration provides redundant measurement paths that enhance detection reliability without requiring complex manual operation
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 allows for precise monitoring and control of plasma processing, minimizing variations and enabling accurate endpoint detection, leading to improved device yields by spatially resolving chemical species concentrations and optimizing process parameters.
Implementation Method 1
Optical emission spectroscopy (OES) has proven itself as a useful tool for process development and monitoring in plasma processing. In OES, the presence and concentrations of certain chemical species of particular interest, such as radicals, is deduced from acquired optical (i.e. light) emission spectra of the plasma
Implementation Method 2
Computed tomographic techniques to localize and pinpoint chemical species during plasma processing
Data Source
AI summary
Described herein are technologies to facilitate computed tomographic techniques to help identifying chemical species during plasma processing of a substrate (e.g., semiconductor wafer) using optical emission spectroscopy (OES). More particularly, the technology described herein uses topographic techniques to spatially resolves emissions and absorptions in at least two-dimension space above the substrate during the plasma processing (e.g., etching) of the substrate. With some implementations utilize optical detectors positioned along multiple axes (e.g., two or more) to receive incident incoming optical spectra from the plasma chamber during the plasma processing (e.g., etching) of the substrate. Because of the multi-axes arrangement, the incident incoming optical spectra form an intersecting grid.