Quadrupole Antenna for Uniform Plasma Generation
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Solution Overview
Problem
Traditional RF ICP/TCP systems generate non-uniform plasma across semiconductor substrates, leading to uneven processing and requiring close coil placement to the dielectric window, which can cause capacitive voltage issues and complicate operations.
Innovation Solution
A quadrupole antenna configuration with nested or stacked spiral dipole antennas is used over the dielectric window, generating a uniform near-field Poynting vector to excite and ionize process gases, eliminating the need for close coil placement and reducing capacitive coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional RF ICP/TCP systems use inductor coils placed close to the dielectric window, then plasma generation is achieved, but capacitive voltage issues arise and Faraday shields are required, complicating the system
Solution Approach 1:
The single inductor coil is segmented into multiple nested coils with different turn counts and geometries. Each coil segment contributes differently to the magnetic field distribution, enabling uniform plasma generation without requiring close placement to the dielectric window, thereby eliminating capacitive voltage issues and the need for Faraday shields
Solution Approach 2:
Multiple coils are nested within each other with varying turn counts (e.g., 10 turns, 20 turns, 30 turns). The nested configuration allows each coil to contribute to the overall magnetic field in a controlled manner, achieving uniform plasma distribution while maintaining a compact structure that does not require close proximity to the dielectric window
2Reliability
If inductor coils are placed close to the dielectric window, then plasma generation occurs, but strong capacitive voltage is generated, requiring Faraday shields
Solution Approach 1:
The system transitions from a single-plane coil configuration to a multi-dimensional nested coil structure. By distributing coils in multiple layers with different geometries and turn counts, the magnetic field is generated more efficiently, reducing reliance on close proximity to the dielectric window and thereby minimizing capacitive voltage effects
3Reliability
If traditional plasma generation systems are used, then plasma is generated in a ring region over the substrate, but plasma generation is non-uniform across the substrate width
Solution Approach 1:
Different regions of the nested coil structure are designed with specific local characteristics. Inner coils with higher turn counts generate stronger magnetic fields in central regions, while outer coils with fewer turns contribute to edge regions. This local optimization ensures uniform plasma distribution across the entire substrate width, eliminating the ring-shaped non-uniformity
Solution Approach 2:
The system varies multiple parameters across the nested coil structure including turn counts (10, 20, 30 turns), coil geometries, and spatial arrangements. By carefully adjusting these parameters, the magnetic field distribution is optimized to produce uniform plasma generation across the substrate, transforming the traditional ring-shaped pattern into a uniform 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
The solution achieves a spatially uniform plasma generation with reduced ion erosion and eliminates the need for Faraday shields, allowing for more efficient and uniform semiconductor processing without capacitive coupling.
Implementation Method 1
a quadrupole antenna configured to be disposed over a dielectric window of a plasma chamber... generating a uniform near-field Poynting vector to excite and ionize process gases
Implementation Method 2
generating a uniform near-field Poynting vector to excite and ionize process gases in chamber
Data Source
AI summary
An apparatus for generating plasma, including a quadrupole antenna having a center region and an outer region and configured to be disposed over a dielectric window of a plasma chamber. The quadrupole antenna including a first coil defining a first SDA and a second coil defining a second SDA, the first coil being in a nested arrangement within the second coil. The nested arrangement places a turn of the first coil to be adjacent to a corresponding turn of the second coil as the first and second coils spiral from the center region to the outer region of the quadrupole antenna. Adjacent turns of each of the first and second coils are horizontally separated from one another by a distance when disposed over the dielectric window.