Plasma Generator Impedance Control for Uniformity
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Solution Overview
Problem
The uniformity of plasma generated in semiconductor manufacturing processes is compromised due to nonuniform electromagnetic fields caused by increased substrate sizes, leading to decreased RF power transfer at the edges of planar antennas, resulting in standing wave effects and reduced plasma uniformity.
Innovation Solution
A plasma generator design featuring a pair of source and bias electrode units with strategically positioned contact points connected to impedance controllers, allowing for impedance control and uniform plasma distribution, including the use of planar capacitors and dielectric thin film layers to enhance electric field uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the substrate size is increased, then the processing area is expanded, but the uniformity of plasma is decreased due to nonuniform electromagnetic fields at the edges
Solution Approach 1:
The patent applies local quality by introducing impedance boxes at specific locations (edges and corners) of the source electrode unit. These impedance boxes provide localized impedance control to compensate for the nonuniform electromagnetic field distribution that occurs at the edges and corners of large-area substrates, thereby maintaining plasma uniformity across the entire substrate surface while accommodating increased substrate size.
2Device complexity
If a planar antenna is used for plasma generation, then the structure is simple, but the electric field uniformity is decreased between center and edge
Solution Approach 1:
The patent maintains the simplicity of the planar antenna structure while improving electric field uniformity by adding impedance boxes at specific locations. These impedance boxes create localized electromagnetic field adjustments at the edges and corners, compensating for the inherent nonuniformity of planar antennas without requiring a complete redesign of the antenna structure.
Solution Approach 2:
The patent changes the electromagnetic field parameters by introducing impedance control through the impedance boxes. By adjusting the impedance values at specific locations on the source electrode unit, the distribution of the electromagnetic field is modified to achieve more uniform plasma generation across the substrate, particularly at the edges and corners where field nonuniformity is most pronounced.
3Manufacturing precision
If impedance control is implemented at multiple locations, then plasma uniformity is improved, but the device complexity is increased
Solution Approach 1:
The patent implements impedance control at strategically selected locations (edges and corners) rather than uniformly across the entire source electrode unit. This localized approach provides sufficient plasma uniformity improvement while minimizing the number of impedance boxes required, thereby balancing plasma uniformity enhancement with device complexity management.
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 ensures uniform plasma generation and easy control of plasma distribution by managing impedance, resulting in improved electric field uniformity and plasma profiles across the substrate, even with larger substrate sizes.
Implementation Method 1
the RF power is applied to the source electrode 11 and the susceptor 12 from the outside, and a strong electromagnetic field is formed between the source electrode 11 and the susceptor 12, and as a result, plasma PS is generated in the vacuum chamber 10
Implementation Method 2
an impedance controller which is connected with the common contact point to control the impedance
Data Source
AI summary
Provided is a plasma generator for improving uniformity of plasma. The plasma generator which includes a pair of source electrode unit 110 and bias electrode unit 120 disposed to face each other in a vacuum chamber and an RF power unit 132 and a bias RF power unit 142 supplying RF power to the source electrode unit 110 and the bias electrode unit 120, respectively, comprises a common contact point cc which is connected with a plurality of contact points cp disposed along the edge of the source electrode unit 110; and an impedance controller 150 which is connected with the common contact point cc to control the impedance.