Mirror-Symmetrical Coil Structure for Uniform Plasma Etching
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Solution Overview
Problem
The existing coil structures in plasma processing apparatuses generate uneven plasma distribution due to asymmetrical electromagnetic fields, leading to non-uniform etching quality and efficiency.
Innovation Solution
A coil structure with mirror-symmetrical first and second coils, arranged to form annular projections, and connected in a manner that ensures symmetric magnetic and electric field distribution, reducing capacitive coupling and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single coil is wound in involute or concentric circles with geometric distribution, then the coil structure is simple to manufacture, but the electromagnetic field distribution becomes asymmetrical causing uneven plasma distribution
Solution Approach 1:
The coil structure is divided into multiple independent coil units (first coil unit, second coil unit, third coil unit, fourth coil unit) arranged in a specific geometric pattern. Each coil unit can be wound independently using simple involute or concentric circle methods, yet their collective arrangement creates a symmetrical electromagnetic field distribution that ensures uniform plasma distribution across the processing area.
2Device complexity
If coils are arranged in a planar structure with parallel connection, then the device complexity is reduced, but the left and right electromagnetic field distribution becomes asymmetrical
Solution Approach 1:
While individual coils are wound using symmetrical patterns (involute or concentric circles), the patent deliberately introduces asymmetry in the spatial arrangement and connection configuration of multiple coil units. The coils are positioned at specific locations and connected in a configuration that compensates for natural asymmetries, ensuring that the overall electromagnetic field distribution achieves symmetry and uniform plasma generation across the chamber.
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 symmetric plasma distribution improves etching quality and efficiency by generating uniform plasma, enhancing the uniformity of semiconductor processing.
Implementation Method 1
an upper electrode is usually configured to excite and generate plasma
Data Source
AI summary
A coil structure includes a coil set including a first coil and a second coil. The first coil and the second coil are wound to form an annular area. A first end of the first coil and a first end of the second coil are close to an inner ring of the annular area. A second end of the first coil and a second end of the second coil are close to an outer ring of the annular area. The first end of the first coil is electrically connected to the first end of the second coil. A first projection-of the first coil on a plane perpendicular to an axial direction of the coil structure and a second projection of the second coil on the plane are mirror-symmetrical to each other.