Bi-Level Induction Coil Assembly for Uniform Plasma Processing
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Solution Overview
Problem
Conventional plasma processing apparatuses face issues such as severe sputtering of dielectric plates due to RF power capacitive coupling, leading to non-uniform plasma distribution and increased maintenance costs, as well as azimuthal nonuniformity caused by capacitive coupling of induction coils.
Innovation Solution
The use of a dual induction coil assembly with bi-level windings and a Faraday shield to minimize capacitive coupling, ensuring symmetrical and balanced induction coils, which are grounded via capacitors to reduce voltage asymmetries and non-uniformities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional induction coils are used for plasma processing, then plasma generation is achieved, but severe sputtering of dielectric plates occurs due to RF power capacitive coupling
Solution Approach 1:
A Faraday shield is introduced as an intermediary component between the induction coil and the dielectric plate. The shield is connected to ground through a capacitor, which serves as a mediator to block RF power capacitive coupling while maintaining electrical grounding. This intermediary structure prevents direct capacitive coupling that causes sputtering, while still allowing the induction coil to generate plasma effectively.
Solution Approach 2:
The harmful capacitive coupling effect is extracted and separated from the plasma generation function. By introducing the Faraday shield with capacitor grounding, the direct capacitive coupling path between the coil and dielectric plate is removed, eliminating the sputtering problem while preserving the inductive plasma generation mechanism.
2Power
If induction coils are used for plasma processing, then plasma is generated, but azimuthal nonuniformity occurs due to capacitive coupling
Solution Approach 1:
The Faraday shield with capacitor grounding acts as a mediator that uniformizes the electromagnetic field distribution. By blocking asymmetric capacitive coupling effects and providing a symmetric grounding path, the shield eliminates azimuthal nonuniformities in the plasma, achieving more uniform plasma distribution across the processing area.
3Quantity of substance
If high voltage is applied to induction coils for plasma generation, then plasma density is increased, but maintenance cost increases due to dielectric plate sputtering
Solution Approach 1:
The Faraday shield with capacitor grounding serves as a protective intermediary that prevents high voltage capacitive coupling from reaching the dielectric plate. This allows high voltage operation for plasma density control while protecting the dielectric plate from sputtering damage, thereby reducing maintenance costs and extending component life.
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 configuration reduces capacitive coupling, resulting in more uniform plasma distribution and reduced non-uniformities in treatment processes like etching and sputtering, thereby improving process controllability and yield.
Implementation Method 1
an induction coil assembly including a first induction coil and a second induction coil when supplied with RF power induce a plasma
Implementation Method 2
Problems associated with inductively coupled plasma (ICP) sources is a severe sputtering of a dielectric plate separating an ICP coil from a process chamber due to RF power capacitive coupling from the coil to plasma
Data Source
AI summary
An induction coil assembly is disclosed including two induction coils. Each induction coil includes a first winding commencing from a first terminal end in a first position in the z-direction and transitioning to a radially inner position in a plane normal to the z-direction and a second winding commencing from the radially inner position and transitioning to a radially outer position in a second plane normal to the z-direction and terminating in a second terminal end. Plasma processing apparatuses incorporating the induction coil assembly are also provided.