Floating Coil Capacitor for Inductive Plasma Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductively coupled plasma processing apparatuses face challenges in achieving uniform plasma density distribution on substrates due to variations in pressure, RF power, and gas flow rates, making it difficult to maintain high process performance and reproducibility.
Innovation Solution
The use of an electrically floated coil with a capacitor in the plasma processing apparatus, which is coupled to the RF antenna by electromagnetic induction, allows for adjustable capacitance to control the plasma density distribution by varying the electrostatic capacitance, thereby enhancing the uniformity of the plasma process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single RF antenna is used to generate plasma, then the apparatus structure is simple, but the plasma density uniformity on the substrate is insufficient
Solution Approach 1:
The single RF antenna is divided into multiple separate RF antennas (typically three), each independently controllable. This segmentation allows different regions of the substrate to receive plasma from different antennas, enabling spatial control of plasma density distribution and improving uniformity across the substrate surface.
Solution Approach 2:
Each RF antenna can be independently controlled to provide different power levels, allowing local optimization of plasma density in different regions of the processing chamber. This enables tailored plasma conditions for different areas of the substrate, improving overall process uniformity.
2Manufacturing precision
If the processing space size is increased to improve plasma diffusion, then plasma density uniformity improves, but the apparatus volume increases
Solution Approach 1:
Instead of changing the physical dimensions of the processing chamber, the invention changes the operational parameters by introducing multiple independently controllable RF antennas. This allows control of plasma density uniformity through power distribution and phase control of multiple antennas, achieving the desired uniformity without increasing chamber volume.
3Manufacturing precision
If passive antenna is added around RF antenna to control magnetic field distribution, then plasma density distribution can be adjusted, but device complexity increases
Solution Approach 1:
The multiple RF antennas serve dual functions: they generate plasma directly while also creating controllable magnetic field distributions through their spatial arrangement and independent power control. This eliminates the need for separate passive antennas, achieving plasma density control through multi-functional active antennas.
Solution Approach 2:
The invention replaces the mechanical/passive magnetic field control approach (using passive antennas) with an electromagnetic control approach using multiple actively controlled RF antennas. The magnetic field distribution is controlled through phase and amplitude modulation of the RF signals supplied to each antenna, rather than through passive structural elements.
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 solution enables precise control over plasma density distribution, improving the uniformity and reproducibility of the plasma process, even under varying conditions, and reduces the need for complex adjustments to the RF power supply system.
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
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, for mounting thereon a target substrate to be processed; a processing gas supply unit for supplying a desired processing gas to the processing chamber to perform a desired plasma process on the target substrate; and 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 apparatus further includes a floating coil electrically floated and arranged at a position outside the processing chamber where the floating coil is to be coupled with the RF antenna by an electromagnetic induction; and a capacitor provided in a loop of the floating coil.