RF Biased Ion Source for EDMA Energy Spread Reduction
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Solution Overview
Problem
Existing electrodynamic mass analysis (EDMA) systems introduce a large ion beam energy spread and angular spread, leading to increased beam strikes at electrodes and reduced precision in ion implantation, particularly for lower energy ion implantation systems.
Innovation Solution
The use of a radio frequency (RF) biased ion source with a time modulated voltage, in combination with a direct current (DC) power supply, to extract the ion beam, reduces energy spread and improves mass separation capabilities by minimizing energy distribution at the exit of the EDMA filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing EDMA approaches are used to perform mass analysis on the ion beam, then ion separation is achieved, but large ion beam energy spread is introduced
Solution Approach 1:
The patent applies periodic action by using a radio frequency (RF) biased ion source that modulates the extraction voltage at RF frequencies. This periodic voltage modulation creates time-varying electric fields that selectively accelerate ions of specific masses through the EDMA filter, achieving mass separation while controlling energy spread. The RF cycling allows precise timing control of ion extraction and filtering.
Solution Approach 2:
The patent changes the voltage parameter from static DC extraction to dynamic time-modulated RF extraction. By varying the extraction voltage at RF frequencies and adjusting the phase and amplitude of the modulated voltage, the system optimizes both mass separation precision and energy spread control. The parameter changes enable adaptive control of ion beam characteristics throughout the extraction and filtering process.
2Measurement precision
If existing EDMA approaches are used to perform mass analysis on the ion beam, then ion separation is achieved, but increased beam angular spread at the substrate occurs
Solution Approach 1:
The RF-biased ion source creates periodic extraction pulses that synchronize with the EDMA filter operation. This periodic action ensures that only ions with correct mass-to-charge ratios and proper timing reach the substrate, filtering out angularly dispersed ions. The time-modulated extraction creates a more collimated beam by selecting ions that traverse the beamline with minimal angular deviation.
3Measurement precision
If existing EDMA approaches are used to perform mass analysis on the ion beam, then ion separation is achieved, but increased beam strike at electrodes along the ion implanter beamline occurs
Solution Approach 1:
The RF-modulated extraction creates periodic ion bursts that are precisely timed with the EDMA filter acceptance windows. This timing synchronization ensures ions are extracted and filtered in discrete pulses, reducing continuous beam loading and minimizing stray ions that could strike electrodes. The periodic extraction also allows for better space charge management and reduced electrode heating.
4Measurement precision
If an analyzing magnet is used to separate ions of different masses, then mass separation is achieved, but the system becomes large, expensive, and heavy
Solution Approach 1:
The patent replaces the mechanical analyzing magnet system with an electrodynamic mass analysis system using RF-biased ion extraction. Instead of using magnetic fields to bend ion trajectories for mass separation, the system uses time-modulated electric fields to selectively accelerate and filter ions. This substitution eliminates the need for large, expensive magnets and complex mechanical beamline components, reducing system size, cost, and power consumption while maintaining mass separation capability.
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 effectively reduces ion beam energy spread, minimizes angular ion spread at the substrate, and eliminates beam strikes at electrodes, enhancing the precision and efficiency of ion implantation systems.
Implementation Method 1
an extraction power assembly including a radio frequency (RF) power supply and a direct current (DC) power supply electrically coupled with the chamber housing. The first power supply and the second power supply are operable to bias the chamber housing of the ion source with a time modulated voltage to extract an ion beam from the ion source
Implementation Method 2
an electrodynamic mass analysis (EDMA) assembly operable to receive the ion beam and perform mass analysis on the ion beam
Implementation Method 3
an ion source including a power supply, the ion source operable to generate a plasma within a chamber housing
Data Source
AI summary
Provided herein are approaches for performing electrodynamic mass analysis with a radio frequency (RF) biased ion source to reduce ion beam energy spread. In some embodiments, a system may include an ion source including a power supply, the ion source operable to generate a plasma within a chamber housing, and an extraction power assembly including a first power supply and a second power supply electrically coupled with the chamber housing of the ion source, wherein the first power supply and the second power supply are operable to bias the chamber housing of the ion source with a time modulated voltage to extract an ion beam from the ion source. The system may further include an electrodynamic mass analysis (EDMA) assembly operable to receive the ion beam and perform mass analysis on the ion beam.