Segmented Induction Coil Layout for Uniform Plasma Etching
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Solution Overview
Problem
Conventional plasma processing apparatuses face challenges in achieving uniform etching rates due to non-uniform electron and radical density distributions within the processing chamber.
Innovation Solution
The apparatus includes a chamber with a dielectric member and a cover featuring separate gas introduction paths and induction coils positioned to control electron and radical density distributions by adjusting high-frequency power and gas flow rates, ensuring independent controllability and reducing magnetic field interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single induction coil is used to generate plasma in the chamber, then the device structure is simple, but the electron density distribution and radical density distribution become non-uniform, resulting in poor etching uniformity
Solution Approach 1:
The induction coil system is segmented into multiple independent induction coils (first induction coil for central region, second induction coil for peripheral region). Each coil can be independently controlled to generate plasma with specific electron density and radical density distributions in different spatial zones, thereby achieving uniform etching across the entire substrate surface while maintaining manageable device complexity through modular design
Solution Approach 2:
Different regions of the chamber are provided with different plasma characteristics through locally optimized induction coils. The first induction coil is configured to produce plasma with electron density and radical density suitable for the central region, while the second induction coil produces plasma with different parameters for the peripheral region. This local quality differentiation ensures uniform etching performance across the substrate
2Manufacturing precision
If gas is introduced uniformly across the chamber, then the gas distribution is simple, but the radical density distribution becomes non-uniform, affecting etching uniformity
Solution Approach 1:
The gas introduction system is segmented into multiple independent gas introduction paths (first gas introduction path, second gas introduction path, etc.), each corresponding to different spatial regions of the chamber. Each gas introduction path can independently control the flow rate and distribution of source gas in its designated region, enabling precise control of radical density distribution to achieve uniform etching while maintaining a modular and manageable gas delivery structure
Solution Approach 2:
Different regions of the chamber receive gas with different flow rates and compositions through locally optimized gas introduction paths. The first gas introduction path delivers gas optimized for the central region, while the second gas introduction path delivers gas optimized for the peripheral region. This local quality differentiation ensures uniform radical density distribution and etching performance across the substrate
3Manufacturing precision
If multiple induction coils are installed to improve plasma uniformity, then the electron density distribution and radical density distribution can be controlled, but magnetic field interference between coils may occur
Solution Approach 1:
The harmful magnetic field interference between induction coils is extracted and eliminated by providing magnetic shielding structures between adjacent coils. These shielding structures selectively block magnetic field lines from one coil from reaching adjacent coils, preventing unwanted electromagnetic coupling and interference while preserving the beneficial plasma generation effects of each coil
Solution Approach 2:
Magnetic shielding structures serve as intermediary elements positioned between adjacent induction coils. These intermediaries act as magnetic field barriers that prevent direct magnetic field interaction between coils, thereby eliminating interference while allowing each coil to independently generate the desired plasma characteristics in its designated region
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 configuration allows for precise control of electron and radical density distributions, enhancing the uniformity of plasma processing and preventing interference between the induction coils, thereby improving the etching process.
Implementation Method 1
an induction coil provided above the dielectric member and configured to, when applied with a high-frequency power, generate a plasma containing the source gas in the chamber
Implementation Method 2
generate a plasma containing the source gas in the chamber
Implementation Method 3
control the electron density distribution and the radical density distribution in the chamber
Data Source
AI summary
Disclosed is a plasma processing apparatus 10 including a chamber 11, a stage 12, a dielectric member 13, a cover 14, a gas introduction path 15, and an induction coil 16. The induction coil 16 includes a first induction coil 17 installed so as to overlap a central region R1 of the dielectric member 13, and a second induction coil 18 installed so as to overlap a peripheral region R2 outside the central region R1 of the dielectric member 13. The cover 14 has a first gas hole 14c formed at a position overlapping the central region R1 and a second gas hole 14d formed at a position overlapping the peripheral region R2. The gas introduction path 15 has a first gas introduction path 15a communicating with the first gas hole 14c and a second gas introduction path 15b communicating with the second gas hole 14d.