Stepped Focus Ring Structure for Plasma Etching Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional focus rings used in substrate processing, particularly during plasma etching, are prone to damage from fluorine-containing etching gases, leading to reduced lifetime due to differential etching rates between inner and outer rings.
Innovation Solution
A focus ring with a stepped structure comprising multiple rings with varying etching rates and depths, where the stepped structure is formed between the second and third rings, effectively preventing damage propagation and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a conventional focus ring with uniform structure is used, then the manufacturing is simple, but the lifetime is reduced due to damage propagation from differential etching rates
Solution Approach 1:
The focus ring is divided into multiple rings (first ring, second ring, third ring) with different materials and etching rates. Each ring is segmented into multiple stepped portions with varying depths and widths, creating a non-uniform structure that prevents damage propagation while maintaining overall functionality.
Solution Approach 2:
Different portions of the focus ring are assigned different local properties through the stepped structure. The first, second, and third rings have different etching rates and are positioned at different depths, creating localized variations in etching resistance that prevent uniform damage propagation across the entire ring structure.
2Reliability
If multiple rings with different etching rates are used, then the etching resistance is improved, but the manufacturing complexity increases
Solution Approach 1:
The focus ring comprises multiple segmented rings (first ring with silicon carbide, second ring with silicon oxide, third ring with silicon carbide) that can be manufactured separately and then assembled. This segmentation allows each ring to be optimized for its specific etching resistance requirements while simplifying the overall manufacturing process through modular construction.
Solution Approach 2:
The focus ring uses composite material construction with alternating layers of silicon carbide (high etching resistance) and silicon oxide (lower etching rate). This composite structure leverages the complementary properties of different materials to achieve superior overall etching resistance while maintaining manufacturability through established material deposition techniques.
3Reliability
If the stepped structure extends deeper toward the substrate, then the damage prevention is enhanced, but the structural complexity increases
Solution Approach 1:
The stepped structure is divided into multiple discrete stepped portions (first, second, third, and fourth stepped portions) with progressively varying depths and widths. This segmentation creates a staged protection system where each stepped portion addresses specific damage propagation pathways at different radial positions, enhancing damage prevention while maintaining manageable structural complexity.
Solution Approach 2:
The stepped structure introduces a radial dimension variation to the focus ring, creating depth variations that extend toward the substrate. By utilizing this additional spatial dimension, the design achieves enhanced damage prevention through multi-level protection without requiring excessive structural complexity, as the stepped portions are systematically arranged rather than randomly configured.
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 stepped structure significantly increases the focus ring's etching resistance and durability, resulting in a substantially longer lifetime for the focus ring and associated process chambers.
Implementation Method 1
a plasma generating unit generating a plasma from the process gas in the process space
Implementation Method 2
the first ring may have a first etching rate, the second ring may have a second etching rate, and the third ring may have a third etching rate. In this case, with respect to an etching gas including fluorine, the first etching rate may be substantially the same as the second etching rate, and the third etching rate may be substantially greater than the first etching rate and the second etching rate
Data Source
AI summary
An apparatus for processing a substrate may include a processing module including at least one process chamber for performing a desired process on a substrate and an index module transferring the substrate into the processing module from an outside. The at least one process chamber may include a housing providing a process space therein, a supporting unit disposed in the housing to support a substrate, the supporting unit including a focus ring having a plurality of rings, a gas supply unit providing a process gas into the process space, and a plasma generating unit generating a plasma from the process gas in the process space. The focus ring may include a stepped structure having a plurality of stepped portions downwardly provided toward the substrate.