Rotatable Magnetron Assembly for PVD Uniformity
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Solution Overview
Problem
In physical vapor deposition (PVD) processes, maintaining uniformity and particle performance becomes increasingly difficult as the distance between the substrate and the sputtering target increases, due to decreased magnetron influence and ion diffusion.
Innovation Solution
A magnetron assembly with a shunt plate and rotatable closed loop magnetic pole around the peripheral edge, combined with an open loop magnetic pole featuring two rows of magnets about the central axis, is used to enhance plasma density and uniformity, particularly at increased target to substrate distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the distance between the substrate and the sputtering target is increased to increase plasma density and improve bottom coverage, then the plasma density and volume increase, but the magnetron influence decreases making it more difficult to meet uniformity and particle performance
Solution Approach 1:
The magnetron assembly is segmented into multiple magnetic pole pairs arranged in a specific pattern around the target. This segmentation creates multiple localized magnetic fields that collectively maintain plasma density and magnetron influence across the entire target surface, even at increased distances from the substrate.
Solution Approach 2:
Different regions of the target surface are provided with different magnetic field characteristics through the specific arrangement of magnetic pole pairs. This local optimization ensures that each region maintains appropriate plasma density and magnetron influence, preserving deposition uniformity across the entire target area despite increased substrate distance.
2Quantity of substance
If the distance between the substrate and the sputtering target is increased to improve bottom coverage, then the plasma volume increases, but particle performance deteriorates due to ion diffusion
Solution Approach 1:
The segmented magnetic pole structure creates multiple confined plasma regions that reduce ion diffusion across the target surface. This segmentation maintains particle performance by preventing excessive ion spread while still allowing increased plasma volume to improve bottom coverage.
Solution Approach 2:
The magnetron assembly is designed to rotate, dynamically adjusting the magnetic field configuration during operation. This dynamic adjustment optimizes plasma confinement and particle performance throughout the sputtering process, maintaining reliability even at increased substrate distances.
3Device complexity
If a traditional magnetron configuration is used to maintain magnetron influence, then the structure is simpler, but deposition uniformity deteriorates at increased target to substrate distances
Solution Approach 1:
The magnetron uses multiple segmented magnetic pole pairs instead of a single continuous magnetic structure. This segmentation, while increasing structural complexity, enables precise control of the magnetic field distribution, thereby maintaining deposition uniformity at increased distances from the substrate.
Solution Approach 2:
The magnetic pole pairs are arranged in an asymmetric pattern optimized for the specific geometry of the target and substrate configuration. This asymmetric arrangement creates a tailored magnetic field distribution that compensates for the increased distance effects, maintaining uniformity without requiring excessive structural complexity.
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 improves deposition uniformity, reduces particle size, and prevents re-deposition, thereby extending target life and ensuring consistent layer formation across larger substrates.
Implementation Method 1
a magnetron positioned at the back of the sputtering target to project a magnetic field into the processing space to increase the density of the plasma
Implementation Method 2
shunt plate and rotatable closed loop magnetic pole around the peripheral edge
Implementation Method 3
sputtering metal atoms from the target using the plasma in the PVD chamber sufficient to ionize a predominant portion of the metal atoms sputtered from the target
Data Source
AI summary
Methods and apparatus for a magnetron assembly are provided herein. In some embodiments, a magnetron assembly includes a shunt plate having a central axis and rotatable about the central axis, a closed loop magnetic pole coupled to a first surface of the shunt plate and disposed 360 degrees along a peripheral edge of the shunt plate, and an open loop magnetic pole coupled at a the first surface of the shunt plate wherein the open loop magnetic pole comprises two rows of magnets disposed about the central axis.