Symmetric RF Distribution Plate for Plasma Uniformity
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Solution Overview
Problem
Plasma non-uniformities in substrate processing systems, such as PVD chambers, due to openings in target assemblies, negatively affect substrate processing, despite central RF feed structures being used to improve plasma uniformity.
Innovation Solution
The implementation of a substrate processing system with a target and source distribution plate having symmetrically disposed features to ensure equal radial RF distribution and return path lengths, along with a magnetron assembly and RF feed structure aligned with the central axis, to maintain uniform RF energy distribution and return paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a central RF feed structure is used to provide RF power to the target, then plasma uniformity is improved, but plasma non-uniformities still occur due to openings in the target assembly components
Solution Approach 1:
The patent applies asymmetry by strategically positioning openings and features in the target assembly components to create symmetric RF distribution paths. The openings are arranged so that RF energy travels equal distances in opposing radial directions from the central axis, compensating for the disruptive effect of openings while maintaining the central RF feed structure.
Solution Approach 2:
The patent creates equipotential conditions by ensuring that all radial RF distribution paths from the central axis to the peripheral edges have equal lengths. This equalizes the RF energy distribution across the target surface, counteracting the non-uniformities introduced by openings in the target assembly components.
2Adaptability or versatility
If openings are provided in target assembly components for functional purposes, then device functionality is enabled, but RF distribution symmetry is disrupted causing plasma non-uniformities
Solution Approach 1:
The patent positions openings asymmetrically in individual components but arranges them symmetrically overall around the central axis. This allows each component to have necessary functional openings while the complete assembly maintains symmetric RF distribution paths, enabling both functionality and uniformity.
3Manufacturing precision
If radial RF distribution paths of equal length are provided in opposing directions from the central axis, then plasma uniformity is enhanced, but device complexity increases due to symmetric feature arrangement
Solution Approach 1:
The patent divides the target assembly into multiple components (target, source distribution plate, ground plate) with features arranged symmetrically. Each component can be manufactured and adjusted independently to achieve the overall symmetric RF distribution, reducing the complexity of manufacturing the entire assembly as a single symmetric unit.
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 enhances plasma uniformity by ensuring similar travel lengths for RF energy in both radial directions, improving substrate processing consistency and efficiency.
Implementation Method 1
a source distribution plate having a first diameter bisected by a central axis and disposed between a first peripheral edge... a plurality of first features disposed about the central axis such that a first distance of a first radial RF distribution path between the central axis and the first peripheral edge along a given first diameter is about equal to a second distance of an opposing second radial RF distribution path
Implementation Method 2
a ground plate opposing the target opposing side of the source distribution plate... a plurality of corresponding second features disposed about the central axis, wherein a third distance of a first radial RF return path between the second peripheral edge and the central axis along a given second diameter is about equal to a fourth distance of an opposing second radial RF return path
Implementation Method 3
a magnetron assembly comprising a rotatable magnet disposed within the cavity and having an axis of rotation that is aligned with a central axis of the target
Implementation Method 4
a magnetron assembly comprising a rotatable magnet disposed within the cavity and having an axis of rotation that is aligned with a central axis of the target
Implementation Method 5
an RF feed structure coupled to the source distribution plate to provide RF energy to the source distribution plate, wherein the RF feed structure is aligned with the central axis
Data Source
AI summary
A processing system may include a target having a central axis normal thereto; a source distribution plate having a target facing side opposing a backside of the target, wherein the source distribution plate includes a plurality of first features such that a first distance of a first radial RF distribution path along a given first diameter is about equal to a second distance of an opposing second radial RF distribution path along the given first diameter; and a ground plate opposing a target opposing side of the source distribution plate and having a plurality of second features disposed about the central axis and corresponding to the plurality of first features, wherein a third distance of a first radial RF return path along a given second diameter is about equal to a fourth distance of an opposing second radial RF return path along the given second diameter.