Hidden Deflection Electrode Ion Beam Angular Control
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Solution Overview
Problem
Conventional plasma processing systems face challenges in controlling the angular distribution of ion beams, particularly for treating 3D structures, as existing methods either lack precise control over ion angular distribution or suffer from electrode sputtering due to the immersion of bias electrodes in the plasma, leading to particle deposition on substrates.
Innovation Solution
A plasma processing apparatus utilizing a hidden deflection electrode outside the plasma chamber, in conjunction with an extraction plate having multiple apertures, allows for independent control of ion beam mean angle and angular spread without exposing the electrode to the plasma, thereby preventing sputtering and maintaining in-situ control of ion angular distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bias electrode is immersed in the plasma to control ion angular distribution, then control precision over ion angular distribution is improved, but electrode sputtering occurs leading to particle deposition on substrates
Solution Approach 1:
The deflection electrode is extracted from the plasma environment and placed in a non-plasma region. The electrode remains electrically isolated from the plasma chamber wall while still being able to influence ion trajectories through electric field effects, thereby preventing sputtering while maintaining control capability
Solution Approach 2:
The chamber wall acts as an intermediary barrier between the deflection electrode and the plasma. The electrode is positioned behind the chamber wall, using the wall itself as a physical shield that prevents direct plasma contact while allowing electric field penetration to control ion angles
2Manufacturing precision
If the extraction plate aperture geometry is modified to control ion angular distribution, then control over ion beam shape and angular distribution is improved, but the ability to independently control mean angle and angular spread is limited
Solution Approach 1:
The system transitions from a static aperture geometry control method to a dynamic control method where voltages on the deflection electrode can be adjusted in real-time. This allows the ion angular distribution to be dynamically tuned without physical modifications to the extraction plate
Solution Approach 2:
The control function is segmented into two independent control mechanisms: aperture geometry for beam shape and deflection electrode voltage for angular distribution. This segmentation allows independent optimization of each parameter without compromising the other
3Object-generated harmful factors
If a hidden deflection electrode is placed outside the plasma chamber, then electrode sputtering is prevented, but the complexity of the apparatus increases due to additional electrical isolation requirements
Solution Approach 1:
The chamber wall serves multiple functions simultaneously: it acts as the plasma chamber boundary, provides electrical isolation for the hidden electrode, and serves as a mounting surface for positioning the electrode. This multi-functionality reduces overall system complexity despite the added electrode
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 solution enables precise control of ion beam angular distribution, preventing electrode sputtering and ensuring high-quality substrate processing by maintaining the characteristics of in-situ controllable ion angular distribution while mitigating the detrimental effects of electrode sputtering.
Implementation Method 1
a hidden deflection electrode disposed adjacent to the middle portion outside of the plasma chamber, and electrically isolated from the extraction plate; and a hidden deflection electrode power supply to apply a bias voltage to the hidden deflection electrode, wherein the bias voltage is configured to modify at least one of a mean angle of incidence of ions and a range of angles of incidence
Implementation Method 2
ions are extracted through an aperture of special geometry located in an extraction plate that is placed proximate a plasma. Changing the geometry of the aperture allows changing of the ion angular distribution
Data Source
AI summary
A processing apparatus may include: an extraction plate disposed along a side of a plasma chamber, the extraction plate having a first and second aperture, and middle portion between the first and second aperture, the first and second aperture being configured to define a first and second ion beam when the plasma is present in the plasma chamber and an extraction voltage is applied between the extraction plate and a substrate; a hidden deflection electrode disposed adjacent the middle portion outside of the plasma chamber, and electrically isolated from the extraction plate; and a hidden deflection electrode power supply to apply a bias voltage to the hidden deflection electrode, wherein the bias voltage is configured to modify a mean angle of incidence of ions and/or a range of angles of incidence centered around the mean angle of incidence in the first and second ion beam.