Multi-Frequency RF Plasma Etching for High Aspect Ratio Uniformity
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in efficiently forming high aspect ratio circuit patterns and controlling process parameters during plasma etching, leading to increased fabrication time and potential defects due to non-uniform plasma density and ion energy distribution.
Innovation Solution
A method of plasma etching that utilizes multiple RF powers with different frequencies to generate, equalize, and homogenize plasma density and ion energy, including a first RF power for plasma generation, a second RF power to equalize plasma density, a third RF power to make ions incident on the substrate, and a fourth RF power to homogenize ion energy distribution, applied in a capacitively coupled plasma etching apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple RF powers with different frequencies are applied to control plasma density and ion energy distribution, then manufacturing precision and uniformity of etched openings are improved, but device complexity and process parameter control difficulty increase
Solution Approach 1:
The plasma generation and ion control process is segmented into multiple independent RF power sources operating at different frequencies. Each RF power source (first, second, third, and fourth RF powers) performs a specific function: plasma generation, plasma density equalization, ion incident control, and ion energy distribution homogenization. This segmentation allows independent optimization of each parameter without interfering with others, achieving high uniformity in etched openings while maintaining controllable process complexity through modular power supply design.
2Productivity
If multiple RF powers are used to achieve high aspect ratio etched openings with improved uniformity, then productivity and etch rate are enhanced, but device complexity and process control difficulty increase
Solution Approach 1:
The process utilizes multiple RF power parameters with different frequencies to independently control various aspects of the plasma etching process. By adjusting the first RF power for plasma generation rate, second RF power for plasma density distribution, third RF power for ion incident energy, and fourth RF power for ion energy distribution homogeneity, the system achieves high etch rates with improved uniformity. The parameter changes approach allows flexible optimization of etch rate and quality without requiring fundamental process changes.
3Manufacturing precision
If plasma density is equalized and ion energy distribution is homogenized using additional RF powers, then manufacturing precision is improved, but loss of energy increases due to multiple power sources
Solution Approach 1:
The system employs periodic RF power application with different frequencies to achieve plasma density equalization and ion energy homogenization. The periodic nature of RF power delivery allows for controlled plasma generation and ion acceleration cycles, where energy is efficiently transferred to the plasma during active phases. The different frequencies enable selective excitation of plasma processes at optimal energy levels, reducing overall energy waste while maintaining precise control over plasma characteristics and etching uniformity.
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 approach enables the formation of high aspect ratio etched openings with improved uniformity and reduced defects, enhancing etch rate and processing efficiency by controlling ion energy distribution and plasma density uniformly across the substrate.
Implementation Method 1
a first RF power configured to generate a plasma within the chamber
Implementation Method 2
a second RF power configured to equalize a density of the plasma within the chamber
Implementation Method 3
a third RF power configured to make ions within the plasma incident on the substrate
Implementation Method 4
a fourth RF power configured to homogenize an ion energy distribution of the ions incident on the substrate
Data Source
AI summary
Disclosed are a method of plasma etching and a method of fabricating a semiconductor device including the same. The method of plasma etching includes loading a substrate including an etch target onto a first electrode in a chamber, the chamber including the first electrode and a second electrode arranged to face each other, and etching the target. The etching the target includes applying a plurality of RF powers to one of the first and second electrodes. The plurality of RF powers may include a first RF power having a first frequency in a range from about 40 MHz to about 300 MHz, a second RF power having a second frequency in a range from about 100 kHz to about 10 MHz, and a third RF power having a third frequency in a range from about 10 kHz to about 5 MHz.