Shaped Electrodes for Uniform Plasma Exposure
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Solution Overview
Problem
Current plasma sources in rotating platen processing systems exhibit non-uniform plasma exposure, with greater exposure at the inner diameter compared to the outer diameter, leading to inefficiencies in substrate processing, particularly in atomic layer deposition and chemical vapor deposition processes.
Innovation Solution
A modular plasma source assembly with a housing, RF hot electrode, and return electrode, featuring a gas inlet and RF feed, is designed to create a uniform plasma distribution across the substrate surface by adjusting the position of the RF feed and using claddings to prevent contamination, ensuring consistent ion flux from the inner to the outer diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional plasma source is used in a rotating platen processing system, then plasma exposure is generated, but the plasma exposure is non-uniform with greater exposure at the inner diameter compared to the outer diameter
Solution Approach 1:
The patent applies local quality by varying the gap distance between the plasma source and substrate across the substrate surface. Specifically, the gap distance is adjusted to be smaller at the inner diameter region and larger at the outer diameter region, creating locally optimized plasma exposure conditions that compensate for the rotational motion effects, thereby achieving uniform plasma exposure across the entire substrate surface
2Use of energy by moving object
If the plasma source is positioned closer to the substrate, then plasma exposure intensity increases, but contamination from the plasma source increases
Solution Approach 1:
The patent implements local quality by positioning the plasma source at different distances from the substrate at different radial locations. The source is positioned closer to the substrate at the inner diameter region to provide sufficient plasma exposure intensity, while being positioned farther at the outer diameter region to minimize contamination, thus achieving both adequate plasma exposure and reduced contamination through spatially varying geometry
3Device complexity
If the RF feed is positioned at the center of the RF hot electrode, then power distribution is simplified, but plasma exposure uniformity across the substrate is compromised
Solution Approach 1:
The patent applies asymmetry by deliberately offsetting the RF feed position from the center of the RF hot electrode. The RF feed is positioned at an asymmetric location that corresponds to the asymmetric gap geometry, creating a non-uniform power distribution that compensates for the varying plasma exposure conditions across the substrate, thereby achieving uniform plasma exposure through asymmetric configuration
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 provides uniform plasma exposure and minimizes contamination, enhancing film deposition uniformity and process efficiency by maintaining consistent ion flux across the substrate, addressing the non-uniformity issues in existing systems.
Implementation Method 1
The RF hot electrode is within the housing and has an elongate body with an inner peripheral end near the inner peripheral edge of the housing and an outer peripheral end near the outer peripheral edge of the housing and defining a length of the RF hot electrode. The RF hot electrode includes a leg extending at an angle to the elongate body. The return electrode has an elongate body extending between the inner peripheral edge and the outer peripheral edge of the housing. The return electrode is spaced from the RF hot electrode to provide a gap in which a plasma can form.
Implementation Method 2
The housing includes a gas inlet to form a flow path from the gas inlet to allow a flow of gas to pass through the housing and out an opening in the front face.
Data Source
AI summary
Plasma source assemblies comprising an RF hot electrode having a body and at least one return electrode spaced from the RF hot electrode to provide a gap in which a plasma can be formed. An RF feed is connected to the RF hot electrode at a distance from the inner peripheral end of the RF hot electrode that is less than or equal to about 25% of the length of the RF hot electrode. The RF hot electrode can include a leg and optional triangular portion near the leg that extends at an angle to the body of the RF hot electrode. A cladding material on one or more of the RF hot electrode and the return electrode can be variably spaced or have variable properties along the length of the plasma gap.