Pixelated Faraday Sensor for Ribbon Ion Beam Position Control
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Solution Overview
Problem
Existing beam line systems for semiconductor fabrication struggle to optimize the position and density of ribbon ion beams, leading to issues with beam current uniformity and angular distribution, which affect the quality of the ion implantation process.
Innovation Solution
A calibration sensor system, comprising Faraday sensors, is introduced after the mass analyzer to measure the total current and vertical position of the ion beam, allowing for adjustments to be made by a controller to optimize the beam's density and position, including the use of quadrupole lenses and extraction optics to focus and center the beam in the height direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a ribbon ion beam is used to increase beam width, then the beam current increases, but the vertical position control and density uniformity deteriorate
Solution Approach 1:
The calibration sensor is divided into multiple segments along the vertical axis, with each segment independently measuring the ion beam current at its specific vertical position. This segmentation allows the system to detect vertical position deviations and density non-uniformities, enabling precise control of the wide ribbon beam that would otherwise be difficult to manage.
2Area of stationary object
If the beam width is increased beyond workpiece diameter, then the processing coverage increases, but the beam current uniformity over ROI deteriorates
Solution Approach 1:
The calibration sensor provides real-time feedback on the vertical density distribution of the ion beam by measuring current at multiple vertical positions. This feedback enables the control system to adjust beam parameters to maintain uniform current distribution across the entire wide beam width, ensuring consistent processing quality over the large processing coverage area.
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 effectively improves the vertical position and focus of the ribbon ion beam, enhancing beam current uniformity and reducing angular spread, thereby improving the quality of the ion implantation process.
Implementation Method 1
The calibration sensor may include a plurality of Faraday sensors, where, both the total current and the vertical position of the ion beam can be determined
Implementation Method 2
the controller tunes at least one of the extraction optics and the mass analyzer based on position information from the calibration sensor... at least one quadrupole lens disposed between the ion source and the mass resolving device
Data Source
AI summary
A system and method for optimizing a ribbon ion beam in a beam line implantation system is disclosed. The system includes a calibration sensor disposed in the beam line after the mass analyzer. The calibration sensor is able to measure both the total current of the ribbon ion beam, as well as provide information about its vertical position. Information from the calibration sensor can then be utilized by a controller to adjust various parameters to improve the density as well as the vertical position. In some embodiments, the calibration sensor may include a plurality of Faraday sensors, where, both the total current and the vertical position of the ion beam can be determined. Furthermore, the focus of the ion beam can be estimated based on the distribution of the current in the height direction.