Plasma Etching with Edge-Weighted Magnetic Field Uniformity
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Solution Overview
Problem
Existing plasma etching methods face challenges in achieving uniformity during the selective etching of silicon-containing materials with respect to metal-containing materials, leading to inconsistencies in processing results.
Innovation Solution
A plasma processing apparatus is designed with a magnetic field distribution where the horizontal component on the edge side of the substrate is higher than at the center, promoting uniform plasma density and enhancing the reaction between fluorocarbon deposits and silicon-containing materials while protecting metal-containing regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma from fluorocarbon gas is formed to create deposit on substrate, then selective etching capability is achieved, but in-plane uniformity of etching is poor
Solution Approach 1:
The patent applies local quality by creating different magnetic field strengths at different locations on the substrate. The magnetic field is designed to be stronger at the edge side and weaker at the center side, causing plasma to concentrate differently across the substrate surface. This local variation in plasma density compensates for the natural tendency of plasma to be more dense at the center, achieving uniform etching across the entire substrate while maintaining selective etching capability through fluorocarbon deposit formation.
Solution Approach 2:
The patent changes the magnetic field parameter distribution across the substrate to control plasma behavior. By adjusting the magnetic field strength as a function of position (stronger at edges, weaker at center), the plasma density is modified to achieve uniformity. This parameter change approach allows simultaneous achievement of selective etching (through fluorocarbon chemistry) and uniform etching (through magnetic field-controlled plasma distribution).
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 improves in-plane uniformity in the etching process, ensuring consistent and precise selective etching of silicon-containing regions relative to metal-containing regions on the substrate.
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
fluorocarbon contained in the deposit reacts with silicon oxide in the first region
Implementation Method 4
forming plasma from a rare gas within the chamber to etch the first region by supplying rare gas ions to 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.