Antenna Geometry for Uniform Plasma Distribution
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Solution Overview
Problem
In semi-batch type film forming apparatuses, achieving uniform plasma processing on substrates is challenging due to variations in substrate passage time through the plasma region, which is affected by the antenna shape and microwave distribution.
Innovation Solution
A substrate processing apparatus with a rotatable placing table and a plasma generating section using a substantially regular triangular antenna shape with rotational symmetry, where high-frequency waves are supplied from the center, ensuring uniform microwave distribution and reduced variation in substrate passage time through the plasma region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fan-shaped antenna is used in a semi-batch type film forming apparatus, then the substrate can pass through the plasma region, but the plasma distribution becomes non-uniform due to variations in substrate passage time
Solution Approach 1:
The patent applies asymmetry by using a fan-shaped antenna with two line segments spaced distant from each other as being spaced away from the axis, rather than a symmetric circular antenna. This asymmetric configuration, combined with power feeding from the gravity center, creates a specific microwave distribution pattern that compensates for the non-uniform substrate passage time through the plasma region, thereby achieving uniform plasma distribution across the substrate surface.
Solution Approach 2:
The patent changes the geometric parameters of the antenna (fan shape with specific line segment spacing) and the power feeding position (gravity center) to optimize the microwave distribution. By adjusting these parameters, the plasma generation is controlled to achieve uniform distribution despite the varying substrate passage time different positions on the substrate.
2Manufacturing precision
If the antenna shape is changed to achieve uniform plasma distribution, then plasma uniformity improves, but the device complexity increases
Solution Approach 1:
The fan-shaped antenna with two spaced line segments represents a relatively simple asymmetric geometry compared to more complex antenna arrays. This asymmetric design achieves uniform plasma distribution without requiring multiple antenna elements or complex feed networks, thus maintaining device simplicity while improving plasma uniformity.
Solution Approach 2:
By optimizing the geometric parameters of the fan-shaped antenna (line segment spacing, angle from axis) and the power feeding position (gravity center), the patent achieves uniform plasma distribution with a single antenna structure, avoiding the need for complex multi-element antenna systems and reducing overall device complexity.
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 apparatus achieves increased plasma uniformity and reduced variation in substrate processing time, enhancing the consistency of film deposition on substrates.
Implementation Method 1
an antenna configured to radiate high frequency waves to the plasma generation region
Implementation Method 2
a plasma generating section configured to generate plasma in the plasma generation region which is one region among the plurality of regions, using the gas supplied to the plasma generation region
Data Source
AI summary
A substrate processing apparatus of the present disclosure includes a placing table provided to be rotatable around an axis; a gas supplying section that supplies gas to regions through which a substrate sequentially passes while being moved in a circumferential direction with respect to the axis as the placing table is rotated; and a plasma generating section that generates plasma using the supplied gas. The plasma generating section includes an antenna that radiates microwaves, and a coaxial waveguide that supplies the microwaves to the antenna. Line segments constituting a plane shape of the antenna when viewed in a direction along the axis include two line segments which are spaced to be distant from each other as being spaced away from the axis. The coaxial waveguide supplies the microwaves to the antenna from a gravity center of the antenna.