Annular Magnet Assembly for Uniform Wafer Plasma Density
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Solution Overview
Problem
The miniaturization and high integration of semiconductor devices have increased the sensitivity of plasma processes, leading to non-uniformity in plasma density-radius distribution, which affects the quality and yield of semiconductor products, particularly between the central and edge regions of a wafer.
Innovation Solution
A plasma processing apparatus with a magnet assembly comprising first and second magnets arranged in an annular shape, controlled by a controller to adjust the magnetic field-radius distribution, allowing rotation of the magnets to uniformly distribute plasma density and improve etching uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma processing is performed in conventional apparatus, then semiconductor device manufacturing is enabled, but plasma density uniformity across wafer radius deteriorates
Solution Approach 1:
The magnet assembly applies different magnetic field intensities to different radial regions of the plasma. Specifically, the magnetic field intensity is set to be higher in the central region and lower in the edge region, creating local variations in plasma confinement that compensate for natural density gradients and achieve uniform plasma density across the wafer surface.
Solution Approach 2:
The invention changes the magnetic field parameter (intensity distribution) as a function of radial position. By adjusting the magnetic field intensity across different regions of the plasma, the plasma density distribution is controlled to achieve uniformity, directly addressing the contradiction between manufacturing precision and reliability.
2Productivity
If miniaturization and high integration are pursued, then device complexity increases, but plasma process sensitivity to non-uniformity increases
Solution Approach 1:
The magnet assembly creates locally optimized plasma conditions by applying region-specific magnetic field intensities. This local control ensures that even as device features become smaller and more densely integrated, the plasma process remains uniform across the entire wafer, maintaining manufacturing precision despite increased device complexity.
3Manufacturing precision
If magnet assembly is added to control plasma density, then plasma uniformity improves, but device complexity increases
Solution Approach 1:
The magnet assembly is segmented into multiple independent magnet units arranged radially around the chamber. Each magnet unit can be independently controlled to generate the required radial magnetic field intensity distribution. This segmentation allows complex magnetic field profiles to be achieved using modular, manageable components rather than a single complex magnet system.
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 apparatus enhances plasma density uniformity and etching profile orthogonality by adjusting the magnetic field intensity across the wafer radius, improving the reliability and yield of semiconductor manufacturing processes.
Implementation Method 1
a magnet assembly configured to apply a magnetic field into the chamber
Implementation Method 2
the magnet assembly includes a plurality of first magnets and a plurality of second magnets arranged in an annular shape... to adjust a density-radius distribution of the plasma
Data Source
AI summary
A plasma processing apparatus includes a wafer support fixture in the chamber and configured to support a wafer, an upper electrode in the chamber and spaced apart from the wafter support fixture, a magnet assembly configured to apply a magnetic field into a chamber, the magnet assembly including a plurality of first magnets and a plurality of second magnets arranged in an annular shape, and a horizontal distance from a central axis of the chamber to each of the plurality of first magnets and each of the plurality of second magnets is less than a radius of the wafer.