Inductively Coupled Plasma Apparatus with Correction Coil
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Solution Overview
Problem
Inductively coupled plasma processing apparatuses face challenges in achieving uniform plasma density distribution on substrates, which affects the reproducibility and yield of semiconductor and flat panel display manufacturing processes.
Innovation Solution
The use of a correction coil outside the processing chamber, coupled with the RF antenna by electromagnetic induction, allows for precise control of plasma density distribution through switching devices or variable resistors, enabling arbitrary and accurate adjustment of plasma density profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a typical RF antenna is used to generate plasma, then the plasma generation process is simple, but the uniformity of plasma density on the substrate is insufficient
Solution Approach 1:
The RF antenna is divided into multiple independent segments that can be individually controlled. Each segment can generate plasma with different density characteristics, allowing the overall plasma distribution to be optimized for uniformity across the substrate while maintaining manageable system complexity through modular design.
Solution Approach 2:
The antenna system incorporates variable impedance control that allows dynamic adjustment of plasma generation characteristics. By changing the impedance of different antenna segments independently, the system can adaptively optimize plasma density uniformity across the substrate without requiring a completely complex fixed structure.
2Manufacturing precision
If the processing space is increased to improve plasma diffusion, then plasma uniformity improves, but the apparatus size and complexity increase
Solution Approach 1:
Instead of uniformly increasing the processing space, the invention applies localized plasma generation control through segmented antenna regions. Each segment creates plasma with specific density characteristics tailored to its position, achieving overall uniformity without requiring excessive chamber volume or area.
3Measurement precision
If multiple antenna segments are used with individual RF power supply, then plasma density control precision improves, but device complexity and cost increase
Solution Approach 1:
A single RF power supply unit is designed to perform multiple functions by independently controlling the impedance of different antenna segments. This multi-functional approach achieves precise plasma density control across all segments without requiring separate power supplies for each segment, thereby reducing overall system complexity while maintaining control precision.
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 stabilizes and linearly controls the plasma density distribution, improving the uniformity of the plasma process and enhancing the reproducibility and yield of manufacturing processes.
Implementation Method 1
As an RF current flows through the RF antenna, an RF magnetic field is generated around the RF antenna, wherein the magnetic force lines of the RF magnetic field travel through the dielectric window and the processing space. A temporal alteration of the generated RF field causes an electric field to be induced azimuthally.
Implementation Method 2
a correction coil, provided at a position outside the processing chamber where the correction coil is to be coupled with the RF antenna by an electromagnetic induction, for controlling a plasma density distribution on the substrate in the processing chamber
Implementation Method 3
electrons azimuthally accelerated by the induced electric field collide with molecules and/or atoms of the processing gas, to thereby ionize the processing gas and generate a plasma in a doughnut shape
Data Source
AI summary
A plasma processing apparatus includes a processing chamber including a dielectric window; a coil-shaped RF antenna, provided outside the dielectric window; a substrate supporting unit provided in the processing chamber; a processing gas supply unit; an RF power supply unit for supplying an RF power to the RF antenna to generate a plasma of the processing gas by an inductive coupling in the processing chamber, the RF power having an appropriate frequency for RF discharge of the processing gas; a correction coil, provided at a position outside the processing chamber where the correction coil is to be coupled with the RF antenna by an electromagnetic induction, for controlling a plasma density distribution on the substrate in the processing chamber; a switching device provided in a loop of the correction coil; and a switching control unit for on-off controlling the switching device at a desired duty ratio by pulse width modulation.