Rotatable Aperture Plates for Angled Ion Beam Extraction
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Solution Overview
Problem
Existing methods for generating angled ion beams for semiconductor processing face limitations in achieving high current, low energy beams with adjustable angles, leading to process variations across substrates due to uneven ion beam distribution.
Innovation Solution
A plasma processing apparatus with a plasma chamber and rotatable plates that extract ion beamlets through apertures, allowing for adjustable extraction angles and increased maximum incidence angles, utilizing a combination of plate shapes and electrode voltages to control the ion beam's direction and energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the platen is tilted to generate an angled ion beam, then the ion beam strikes the substrate at a non-zero angle, but the various regions of the substrate are at different distances from the ion beam source causing process variations
Solution Approach 1:
The extraction system is divided into multiple independent aperture elements that can be individually controlled. This segmentation allows each aperture to extract ion beamlets at specific angles while maintaining a fixed platen position, thereby achieving angled ion beam extraction without the substrate distance variations caused by tilting the entire platen.
Solution Approach 2:
The aperture elements are made rotatable or adjustable, allowing dynamic control of the extraction angle. This dynamic adjustment capability enables the system to vary the ion beam angle without mechanically tilting the platen, maintaining consistent substrate-to-source distance while achieving the desired beam angle.
2Adaptability or versatility
If the ion beam source is rotated to achieve the desired angle, then the extraction angle is adjusted, but similar shortcomings occur as tilting the substrate
Solution Approach 1:
Instead of rotating the entire ion beam source, the system segments the extraction apertures into independently controllable elements. Each aperture can be adjusted to extract ion beamlets at different angles, providing adaptability without the uniformity issues caused by source rotation.
Solution Approach 2:
Different regions of the extraction system have locally optimized aperture configurations. Each aperture element can be independently positioned or oriented to extract ion beamlets at specific angles, allowing local adjustment of beam properties without affecting the overall source-to-substrate geometry.
3Adaptability or versatility
If the plasma sheath shape is controlled to vary the extraction angle, then the ion beam angle is adjusted, but limitations exist in terms of the amount of current that may be extracted
Solution Approach 1:
The extraction system uses multiple independent aperture elements instead of relying solely on plasma sheath shape control. This segmentation provides additional degrees of freedom for angle control and allows each aperture to extract ion beamlets independently, thereby maintaining high total current while achieving variable extraction angles.
Solution Approach 2:
The aperture elements are made mechanically adjustable or rotatable, providing dynamic control of the extraction angle that is independent of plasma sheath shape. This dynamic mechanical control allows for precise angle adjustment without limiting the ion current that can be extracted.
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
Enables the generation of high current, low energy angled ion beams with precise angle control, reducing process variations by maintaining consistent substrate-to-ion source distances and achieving higher maximum incidence angles, such as greater than 15°.
Implementation Method 1
an RF coil to energize a process gas to form a plasma in the plasma processing chamber
Implementation Method 2
The extraction aperture includes a plurality of rotatable plates. Ion beamlets are extracted through apertures defined by the plurality of rotatable plates. The degree to which these plates are rotated determines the angle of extraction for the extracted ion beam
Data Source
AI summary
An apparatus for creating an angled ion beam for implanting into a substrate is disclosed. The apparatus includes a plasma chamber in which plasma is created. The extraction aperture includes a plurality of rotatable plates. Ion beamlets are extracted through apertures defined by the plurality of rotatable plates. The degree to which these plates are rotated determines the angle of extraction for the extracted ion beam. These plates may be formed in a plurality of different shapes, which may increase the maximum extraction angle that is achievable. Additionally, electrodes may be disposed near the plates to affect the extraction angle.