Movable Ground Electrode Ion Beam Current Control
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Solution Overview
Problem
Ion implanters face challenges in maintaining stable operation and maximizing beam current over a range of energies, as conventional designs result in lower current extraction for lower ion energies due to electrode separation settings intended to prevent arcing at higher voltages.
Innovation Solution
An adjustable acceleration/deceleration column with a reversibly movable ground electrode allows for varying electrode separation and potential adjustments, optimizing beam current and optics across different ion energies and currents by moving the ground electrode between predefined positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrode separation is increased to prevent arcing at high voltages, then reliability is improved, but beam current decreases
Solution Approach 1:
The ground electrode is made movable along the beam axis, allowing the electrode separation to be dynamically adjusted based on the operating voltage. At high voltages (e.g., 300 kV), the electrode separation is increased to prevent arcing, while at lower voltages (e.g., 1-50 kV), the separation is decreased to maximize beam current extraction. This dynamic adjustment resolves the contradiction between reliability and beam current quantity.
2Productivity
If electrode separation is decreased to increase beam current, then productivity is improved, but electrical breakdown occurs
Solution Approach 1:
The movable ground electrode enables the system to dynamically optimize electrode separation for each operating condition. When operating at lower voltages where high beam current is needed for productivity, the electrode separation is automatically decreased to maximize current extraction. When voltage increases and arcing risk rises, the separation increases to maintain reliability. This dynamic adaptation resolves the contradiction between productivity and electrical breakdown prevention.
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 increases beam current delivery to substrates across a range of ion energies, optimizes beam optics, and avoids electrical breakdown, demonstrating an 88% increase in beam current for lower energies and improved performance in simulations.
Implementation Method 1
a ground electrode disposed adjacent the fixed electrode and configured to conduct the ion beam through a ground electrode aperture, the ground electrode being reversibly movable along a first axis with respect to the fixed electrode between a first position and a second position, wherein a beam current of the ion beam at the substrate varies when the ground electrode moves between the first position and second position
Implementation Method 2
a fixed electrode configured to conduct the ion beam through a fixed electrode aperture and to apply a fixed electrode potential to the ion beam
Implementation Method 3
an ion source to generate an ion beam for treating a substrate
Implementation Method 4
an extraction electrode to extract the ion beam at an initial beam potential
Data Source
AI summary
An apparatus to control an ion beam for treating a substrate. The apparatus may include a fixed electrode configured to conduct the ion beam through a fixed electrode aperture and to apply a fixed electrode potential to the ion beam, a ground electrode assembly disposed downstream of the fixed electrode. The ground electrode assembly may include a base and a ground electrode disposed adjacent the fixed electrode and configured to conduct the ion beam through a ground electrode aperture, the ground electrode being reversibly movable along a first axis with respect to the fixed electrode between a first position and a second position, wherein a beam current of the ion beam at the substrate varies when the ground electrode moves between the first position and second position.