Low-Angle Ion Beam Extraction Assembly With Slit Overlap Control
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Solution Overview
Problem
Conventional ion beam extraction systems struggle to produce ion beams with controlled low angles of incidence and narrow angular spreads, leading to inconsistent treatment of substrates, especially for high aspect ratio device structures, due to the reduction in beam current caused by beam blockers and variations in plasma uniformity.
Innovation Solution
A novel extraction assembly comprising a beam blocker and extraction plate configuration, where the beam blocker overlaps with the extraction plate to create slits, allowing for adjustable overlap distances and slit widths, which controls the angle of incidence and reduces the angular spread of ion beams, ensuring uniform treatment of substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a beam blocker is placed in the middle of the extraction aperture to create angled ion beamlets, then the angle of incidence control is improved, but the beam current is reduced
Solution Approach 1:
The extraction aperture is divided into multiple separate apertures arranged in an array, each aperture generating its own ion beamlet. This segmentation allows the system to achieve the desired angular distribution through the geometric arrangement of multiple small apertures rather than blocking a single large aperture, thereby maintaining higher beam current while still controlling the angle of incidence.
Solution Approach 2:
The invention transitions from a single aperture with a beam blocker (2D blocking approach) to multiple apertures arranged in an array (3D spatial distribution). By distributing apertures across a two-dimensional array, the system achieves angular control through spatial arrangement rather than physical blocking, preserving beam current while controlling incidence angles.
2Quantity of substance
If multiple extraction apertures are provided along the side of a plasma chamber to generate multiple pairs of symmetric ion beamlets, then the beam current is increased, but the plasma uniformity variations cause different regions of the substrate to be treated with different ion beams
Solution Approach 1:
Each extraction aperture in the array is designed with specific local characteristics (aperture size, shape, and orientation) that are optimized for its position in the array. This local optimization ensures that each aperture contributes appropriately to the overall beam distribution, compensating for plasma uniformity variations and achieving consistent treatment across the substrate surface.
Solution Approach 2:
The invention varies parameters such as aperture size, shape, and orientation across the array to compensate for plasma uniformity variations. By adjusting these parameters locally, the system ensures that ion beams extracted from different positions in the plasma chamber all contribute to uniform substrate treatment, maintaining treatment consistency while utilizing multiple apertures for higher beam current.
3Area of stationary object
If an elongated extraction aperture is used to extract ribbon ion beams, then the beam coverage area is increased, but the angular spread of the ion beams becomes wider
Solution Approach 1:
The elongated extraction aperture is segmented into multiple smaller apertures arranged in an array. Each small aperture produces a narrow angular spread, and the collective arrangement of these apertures provides the desired wide coverage area. This segmentation approach decouples the relationship between coverage area and angular spread that exists in single elongated aperture designs.
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 configuration enables the generation of ion beams with controlled low angles of incidence and narrow angular spreads, effectively treating targeted surfaces like sidewalls without affecting other surfaces, while maintaining acceptable beam current levels.
Implementation Method 1
Ions are extracted through an aperture of special geometry located in an extraction plate that is placed proximate a plasma
Implementation Method 2
a plasma chamber to house a plasma
Data Source
AI summary
An extraction assembly may include an extraction plate for placement along a side of a plasma chamber, and having an extraction aperture, elongated along a first direction, and having an aperture height, extending along a second direction, perpendicular to the first direction. The extraction plate defines an inner surface along the extraction aperture, lying in a first plane. A beam blocker is disposed over the extraction aperture, and has an outer surface, disposed in a second plane, different than the first plane. As such, the beam blocker overlaps with the extraction plate along a first edge of the extraction aperture by a first overlap distance, and overlaps with the extraction plate along a second edge of the extraction aperture by a second overlap distance, so as to define a first extraction slit, along the first edge, and a second extraction slit along the second edge.