Vertically Adjustable Plasma Source for Uniform Wafer Exposure
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Solution Overview
Problem
Existing plasma sources in rotating platen processing systems suffer from non-uniform plasma exposure, with plasma density being greater at the inner diameter of the wafer compared to the outer diameter, leading to inefficiencies and potential film quality issues.
Innovation Solution
The development of a modular plasma source with a specific design that includes a top cover, upper and lower housings, an RF hot electrode, and a gas inlet, along with a non-conductive showerhead and cladding layer, which allows for adjustable positioning and improved gas flow uniformity to enhance plasma exposure across the wafer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional plasma source is used in a rotating platen processing system, then plasma is generated to treat the substrate, but plasma exposure is non-uniform with higher density at the inner diameter compared to the outer diameter
Solution Approach 1:
The plasma source is designed with vertically adjustable components including the upper housing, lower housing, and RF hot electrode that can be independently positioned along the vertical axis. This dynamic positioning capability allows optimization of plasma exposure uniformity across the wafer surface by adjusting the gap distances, while maintaining ease of operation through a modular design that simplifies installation and reconfiguration.
2Productivity
If the plasma source is positioned closer to the substrate to improve processing efficiency, then productivity increases, but contamination from the plasma source increases
Solution Approach 1:
The plasma source employs a non-conductive showerhead with specifically designed aperture patterns that create localized plasma generation zones. The showerhead structure directs plasma flux preferentially toward the substrate surface while shielding critical areas from contamination. This allows the plasma source to be positioned closer to the substrate for improved productivity while the localized plasma control minimizes harmful sputtering and contamination effects.
3Ease of operation
If a modular plasma source design is used to improve ease of insertion and adjustment, then ease of operation improves, but device complexity increases
Solution Approach 1:
The plasma source is divided into distinct modular segments including the upper housing, lower housing, RF hot electrode, and non-conductive showerhead that can be independently manufactured, assembled, and adjusted. This segmentation enables easier insertion and positioning operations while the standardized interfaces and alignment features between modules help manage overall system complexity. Each module can be optimized independently for its specific function.
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 solution achieves more uniform plasma exposure across the wafer surface, reducing the gap between the RF hot electrode and the substrate, and minimizing contamination and edge roll-off issues, thereby improving film quality and processing efficiency.
Implementation Method 1
The plasma source consists of a volume where plasma is generated, and a way to expose a workpiece to a flux of charged particles and active chemical radical species
Implementation Method 2
an RF hot electrode... spaced from the lower housing and has an inner end adjacent to and spaced from the inner peripheral edge of the lower housing
Data Source
AI summary
The disclosure describes a plasma source assemblies comprising a differential screw assembly, an RF hot electrode, a top cover, an upper housing and a lower housing. The differential screw assembly is configured to provide force to align the plasma source assembly vertically matching planarity of a susceptor. More particularly, the differential screw assembly increases a distance between the top cover and the upper housing to align the gap with the susceptor. The disclosure also provides a better thermal management by cooling fins. A temperature capacity of the plasma source assemblies is extended by using titanium electrode. The disclosure provides a cladding material covering a portion of a first surface of RF hot electrode, a second surface of RF hot electrode, a bottom surface of RF hot electrode, a portion of a surface of the showerhead and a portion of lower housing surface.