Multi-Frequency Plasma Etching Control for High-Aspect-Ratio Precision
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Solution Overview
Problem
Current plasma etching technologies face challenges in achieving high aspect ratio etching for semiconductor devices, particularly with RF power management, which affects the efficiency and precision of the etching process.
Innovation Solution
A plasma etching apparatus that independently controls multiple frequency RF powers, using a controller to manage high-frequency and low-frequency RF powers applied to different electrodes, allowing for precise control of the etching process by ramping up and down these powers during specific time periods to optimize etching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple frequency RF powers are applied to electrodes for plasma etching, then etching performance and aspect ratio are improved, but device complexity and control difficulty increase
Solution Approach 1:
The patent divides the RF power control into multiple independent frequency channels (e.g., 13.56 MHz and 27.12 MHz) with separate power supplies and control circuits for different electrodes. This segmentation allows precise control of plasma generation and ion bombardment independently, improving etching precision while managing complexity through modular architecture
Solution Approach 2:
The patent implements dynamic control of RF power frequencies and amplitudes during the etching process. The controller adjusts power parameters in real-time based on process requirements, enabling optimization of aspect ratio and etching uniformity. This dynamic adjustment capability resolves the contradiction by providing high precision control without requiring permanently complex hardware
2Productivity
If RF power is continuously applied during etching, then productivity is improved, but harmful effects such as clogging increase
Solution Approach 1:
The patent employs periodic pulsed RF power application instead of continuous power supply. The controller applies RF power in controlled pulses with specific duty cycles, allowing plasma generation during active periods while preventing polymer accumulation and clogging during off periods. This periodic action maintains high etching speed by ensuring continuous productive cycles without harmful side effects
Solution Approach 2:
The patent maintains continuous etching productivity through optimized pulse sequencing and multi-frequency coordination. By carefully designing pulse widths, frequencies, and power levels, the system ensures that useful etching action continues without interruption while preventing harmful effects. The continuous adjustment of power parameters keeps the process in the optimal regime throughout operation
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 enhances etching performance by improving the aspect ratio and preventing clogging, leading to more efficient and precise semiconductor device manufacturing.
Implementation Method 1
a first source electrode electrically connected to the first electrostatic chuck and configured to supply a first high-frequency RF power thereto
Implementation Method 2
a first bias electrode electrically connected to the first electrostatic chuck and configured to supply a first low-frequency RF power thereto
Implementation Method 3
a first electrostatic chuck configured to support a substrate; a second electrostatic chuck around an edge of the first electrostatic chuck
Data Source
AI summary
A plasma etching apparatus may include a first source electrode, a first bias electrode, and a second bias electrode configured to generate a plasma by supplying energy to a process gas injected into a chamber; and a controller. The controller may be configured to supply a first high-frequency RF power, a first low-frequency RF power, and a second low-frequency RF power to the chamber during a first period from a first time to a second time; ramp down and turn off the first high-frequency RF power to the chamber during a second period from the second time to a third time; and ramp down and turn off the first low-frequency RF power to the chamber during a third period from the second time to a fourth time different from the third time. The third period may be smaller than ½ of the first period and greater than the second period.