Plasma Etching Magnetic Field Layout for Uniform Silicon Selectivity
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Solution Overview
Problem
Existing plasma etching methods face challenges in achieving uniformity in selectively etching silicon-containing materials with respect to metal-containing materials, leading to non-uniform processing results due to non-uniform plasma density distribution across the substrate.
Innovation Solution
A plasma processing apparatus with a magnetic field distribution where the horizontal component on the edge side of the substrate is higher than at the center, using an electromagnet to form a uniform plasma density distribution, promotes the reaction between fluorocarbon and silicon-containing materials while protecting metal-containing regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is performed without magnetic field control, then the etching process can be carried out, but non-uniform plasma density distribution results in poor in-plane uniformity of etching across the substrate
Solution Approach 1:
The patent applies local quality by creating a non-uniform magnetic field distribution specifically at the edge regions of the substrate. The electromagnet is positioned and configured to generate enhanced magnetic flux density at the substrate edges compared to the center, thereby locally correcting the plasma density distribution without requiring uniform magnetic field enhancement across the entire substrate area.
Solution Approach 2:
The patent introduces a magnetic field dimension to control plasma distribution. By adding the magnetic field as a new control dimension with specific spatial distribution characteristics (higher at edges, lower at center), the system compensates for the radial plasma density gradient and achieves uniform plasma density across the substrate surface.
2Manufacturing precision
If uniform plasma density is achieved through magnetic field control, then selective etching uniformity improves, but the device structure becomes more complex with additional electromagnet components
Solution Approach 1:
The patent changes the magnetic field parameter distribution in space, creating a specific profile where magnetic flux density is higher at substrate edges and lower at the center. This spatial parameter variation compensates for the plasma density gradient, enabling uniform plasma density and improved selective etching uniformity without requiring complex multi-component systems.
3Manufacturing precision
If magnetic field is enhanced at substrate edges, then plasma density uniformity improves, but energy consumption increases due to electromagnet operation
Solution Approach 1:
The electromagnet is designed to generate magnetic field enhancement only where needed - at the edge regions of the substrate - rather than uniformly across the entire substrate area. This localized magnetic field application corrects plasma density non-uniformity at the edges while minimizing unnecessary energy consumption in the center region where plasma density is already sufficient.
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 approach enhances the in-plane uniformity of the etching process by ensuring uniform plasma density distribution, improving the selective etching of silicon-containing regions relative to metal-containing regions.
Implementation Method 1
a magnetic field distribution in which a horizontal component on an edge side of the substrate is higher than a horizontal component on a center of the substrate is formed by an electromagnet
Implementation Method 2
forming plasma from a processing gas containing a fluorocarbon gas within the chamber to form a deposit containing fluorocarbon on the substrate
Implementation Method 3
supplying rare gas ions to the substrate to react the fluorocarbon contained in the deposit on the substrate with the silicon containing material of the first region
Implementation Method 4
form a deposit containing fluorocarbon on the substrate
Data Source
AI summary
In an etching method, plasma from a processing gas containing a fluorocarbon gas is formed within a chamber of a plasma processing apparatus, and a deposit containing fluorocarbon is formed on a substrate. The substrate includes a first region formed of a silicon containing material and a second region formed of a metal containing material. Subsequently, plasma from a rare gas is formed within the chamber, and rare gas ions are supplied to the substrate. As a result, the first region is etched by the fluorocarbon contained in the deposit. When the plasma from the rare gas is formed, a magnetic field distribution in which a horizontal component on an edge side of the substrate is higher than a horizontal component on a center of the substrate is formed by an electromagnet.