External Magnet Assembly for Single-Turn PVD Etch Uniformity
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Solution Overview
Problem
Physical vapor deposition (PVD) chambers with single turn internal coils experience asymmetrical material etch on substrates due to low bias power and high pressure, leading to non-uniform plasma distribution and etch rates.
Innovation Solution
An external magnetic field is generated around the PVD chamber using a housing with arcuate base plates and multiple magnets arranged asymmetrically to improve plasma density and uniformity, reducing capacitive coupling effects and enhancing ion distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single turn internal coil is used in the PVD chamber, then the device complexity is reduced, but etch uniformity deteriorates due to asymmetrical material etch
Solution Approach 1:
The patent applies asymmetry by arranging magnets in an asymmetric pattern outside the chamber body. This asymmetric magnetic field configuration compensates for the asymmetrical material etch caused by the simple single-turn coil, thereby improving etch uniformity without increasing coil complexity
Solution Approach 2:
The patent introduces magnets as an intermediary element outside the chamber to influence the plasma distribution and material etch process. These magnets act as a mediator that corrects the asymmetrical etching issue without requiring modification of the internal coil structure
2Use of energy by moving object
If low bias power and high pressure are used in the PVD chamber, then energy consumption is reduced, but plasma distribution uniformity deteriorates
Solution Approach 1:
The asymmetric magnet arrangement creates a non-uniform magnetic field that compensates for the non-uniform plasma distribution resulting from low bias power and high pressure conditions, achieving better etch uniformity under these energy-efficient operating parameters
3Device complexity
If magnets are arranged symmetrically about the chamber body, then the device structure is simplified, but etch uniformity deteriorates due to asymmetrical material etch
Solution Approach 1:
The patent deliberately employs asymmetric magnet arrangement to counteract the asymmetrical material etch problem. The asymmetric configuration of magnets outside the chamber creates a compensating magnetic field that improves etch uniformity, demonstrating that intentional asymmetry can solve symmetry-related process defects
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 external magnetic field enhances etch uniformity by improving plasma density and ion distribution, addressing asymmetrical etch issues and achieving more consistent deposition rates across the substrate.
Implementation Method 1
generating a magnetic field external to a physical vapor deposition (PVD) chamber to improve etch uniformity
Implementation Method 2
The process chambers may use coils disposed between a target and a substrate support of the process chamber to maintain a plasma in the process chamber
Data Source
AI summary
Methods and apparatus for generating a magnetic field external to a physical vapor deposition (PVD) chamber to improve etch or deposition uniformity on a substrate disposed inside of the PVD chamber are provided herein. In some embodiments, a process chamber, includes a chamber body defining an interior volume therein; a pedestal disposed in the interior volume for supporting a substrate; a coil disposed in the interior volume above the pedestal; and an external magnet assembly, comprising: a housing coupled to the chamber body; and a plurality of magnets disposed external to the chamber body coupled to the housing and arranged asymmetrically about the chamber body.