Pulsed Magnetic Field Plasma Etching for Edge Uniformity
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Solution Overview
Problem
Plasma etching technologies face challenges in achieving uniformity and precision, particularly in patterning features at atomic scale dimensions, due to non-uniform plasma distributions leading to issues like bowed profiles at the edges of substrates during semiconductor manufacturing.
Innovation Solution
A plasma etching system that incorporates a set of electromagnets to apply a pulsed magnetic field independently from the RF power source, modulating plasma parameters such as electron temperature and loss rate to enhance uniformity, with the magnetic field being stronger near the edge of the plasma to reduce etch rate differences between edge and central regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used, then etching process can be performed, but non-uniform plasma distribution causes bowed profiles at substrate edges
Solution Approach 1:
The patent applies a magnetic field that is stronger near the edge of the plasma than near the center, creating local variations in plasma parameters. This local quality adjustment compensates for the natural non-uniformity of plasma distribution, reducing etch rate differences between edge and central regions of the substrate.
Solution Approach 2:
The patent employs a pulsed magnetic field that can be dynamically adjusted in strength and timing. By controlling the magnetic field pulses independently from the RF power source, the system can dynamically modulate plasma parameters such as electron temperature and loss rate to maintain uniform etching across the substrate.
2Productivity
If feature size is shrunk to increase packing density, then cost is reduced, but patterning precision and profile control become more challenging
Solution Approach 1:
The patent changes physical parameters of the plasma by introducing a magnetic field, which modifies electron temperature, electron loss rate, and plasma density. These parameter changes enable precise control of etching characteristics at smaller feature sizes, maintaining patterning accuracy while supporting higher packing densities.
3Manufacturing precision
If magnetic field is applied to modulate plasma parameters, then uniformity is improved, but device complexity increases
Solution Approach 1:
The patent integrates the magnetic field generation capability into the existing plasma processing system. The electromagnets are configured to work alongside the RF power source, allowing the same system to perform both plasma generation and magnetic field application, thereby reducing overall system complexity despite the added functionality.
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 achieves improved uniformity and precision in plasma etching, reducing bowing issues and maintaining optimized balances of radical and etch byproduct species, resulting in more consistent and directional etch profiles across the substrate.
Implementation Method 1
a RF power source configured to generate a plasma in the plasma processing chamber
Implementation Method 2
a set of electromagnets configured to apply a magnetic field in the processing chamber
Implementation Method 3
modulating plasma parameters such as electron temperature and loss rate to enhance uniformity, with the magnetic field being stronger near the edge of the plasma
Data Source
AI summary
A plasma etching system for a substrate including: a plasma processing chamber; a substrate holder disposed in the plasma processing chamber; a RF power source configured to generate a plasma in the plasma processing chamber; a set of electromagnets configured to apply a magnetic field in the processing chamber, the magnetic field of the set of the electromagnets being independent from a magnetic field generated by the RF power source; and a microprocessor coupled to the RF power source and the set of electromagnets, the microprocessor including a non-volatile memory having a program including instructions to: power the RF power source and generate the plasma in the processing chamber to etch the substrate; and provide a power pulse train to the set of electromagnets and generate the magnetic field that is pulsed, in the plasma processing chamber.