Spatially Resolved Ion Beam Metrology via Optical Collection
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Solution Overview
Problem
Current metrology techniques for ion beam characterization in plasma etchers, such as Faraday cup arrays and free space optical emission spectrum (OES), face limitations including contamination, beam path perturbations, and inability to resolve spatial distribution of ion beams, leading to inaccurate results and noise interference.
Innovation Solution
A spatially resolved optical metrology system that includes an ion source, an optical collection module with dual apertures for precise light signal measurement, and a detection module to output electric signals, enabling non-invasive beam profiling and endpoint control with improved signal noise ratio and material exposure analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Faraday cup array is used for ion beam metrology, then beam current measurement is achieved, but contamination and beam path perturbation occur
Solution Approach 1:
The patent replaces the mechanical Faraday cup array system with an optical measurement system that uses light emission detection. Instead of physically intercepting ion beams with metal cups, the system detects optical signals emitted by ions in the beam, eliminating mechanical contact and associated contamination issues.
Solution Approach 2:
The patent introduces optical signals as an intermediary medium to measure ion beam properties indirectly. Rather than direct electrical measurement that causes contamination, the system uses light emission as a mediator to transfer information about ion beam characteristics without physical interaction that would cause harm.
2Reliability
If free space OES is used for process endpoint control, then endpoint detection is achieved, but spatial distribution resolution is lost
Solution Approach 1:
The patent segments the optical detection into multiple spatially resolved channels corresponding to different positions in the ion beam. By dividing the detection space and assigning detectors to specific regions, the system simultaneously achieves reliable endpoint control and precise spatial distribution measurement.
Solution Approach 2:
The patent adds spatial dimensionality to the optical emission spectroscopy by positioning detectors at multiple locations and angles relative to the ion beam. This transforms the measurement from a single integrated signal into a multi-dimensional spatial map, enabling both endpoint control and spatial resolution.
3Productivity
If free space OES is used for ion beam measurement, then process monitoring is achieved, but optical noise from environment and materials increases
Solution Approach 1:
The patent applies local quality by positioning detectors to receive optical signals from specific localized regions of the ion beam while blocking signals from other areas. This spatial selectivity ensures that each detector measures only the relevant local emission, filtering out environmental and material noise from unrelated sources.
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 system provides high spatial resolution and sensitivity for ion beam metrology, reducing contamination and noise, and enhancing endpoint control and plasma metrology capabilities, offering a more accurate and reliable method for monitoring and controlling ion beam processes.
Implementation Method 1
an optical device for measuring a light signal of a volume of the ion beam
Implementation Method 2
a detector for receiving the measured light signal and outputting an electric signal corresponding to the sampled volume of the ion beam
Data Source
AI summary
Provided herein are systems and methods for spatially resolved optical metrology of an ion beam. In some embodiments, a system includes a chamber containing a plasma/ion source operable to deliver an ion beam to a wafer, and an optical collection module operable with the chamber, wherein the optical collection module includes an optical device for measuring a light signal from a volume of the ion beam. The system may further include a detection module operable with the optical collection module, the detection module comprising a detector for receiving the measured light signal and outputting an electric signal corresponding to the measured light signal, thus corresponding to the property of the sampled plasma volume.