Modulated Plasma Etching for High Aspect Ratio Selectivity
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Solution Overview
Problem
The increasing complexity and aspect ratios in semiconductor integrated circuits require advanced etching processes that achieve selective material removal and profile control, which existing plasma etching techniques struggle to meet effectively.
Innovation Solution
A modulated plasma etching process is employed, involving a power modulation cycle with sequential RF power application steps at different levels, including a power-off state, to selectively remove one material over another on a substrate, ensuring target etch selectivity and profile control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used, then the etching process is simple and fast, but selective material removal and profile control are insufficient for high aspect ratio features
Solution Approach 1:
The patent applies periodic modulation of RF power during plasma etching, cycling between different power levels to achieve selective material removal. The modulated plasma etching process uses time-varying power application to control etch selectivity and profile, transforming the continuous etching process into periodic cycles that enhance precision for high aspect ratio features while managing process complexity
Solution Approach 2:
The patent introduces dynamic control of etching parameters by modulating RF power in real-time during the etching process. The power modulation cycle dynamically adjusts plasma conditions to optimize selective removal of first material versus second material, enabling adaptive control that responds to changing etch depths and material exposures throughout the process
2Productivity
If higher device density and miniaturization are achieved, then circuit performance improves, but aspect ratios and material complexity increase making etching more difficult
Solution Approach 1:
The modulated plasma etching process uses periodic power modulation to maintain precise control over selective etching as device density and aspect ratios increase. By cycling through different power levels, the process adapts to varying material compositions and geometries encountered in high-density integrated circuits, ensuring consistent selectivity across complex multi-material structures
Solution Approach 2:
The patent changes plasma process parameters through RF power modulation, dynamically adjusting energy input to the plasma during etching. This parameter variation enables the process to handle increased material complexity and higher aspect ratios by optimizing ion bombardment energy and chemical reactivity at different stages of the etch, maintaining precision despite increased device density requirements
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 modulated plasma etching process effectively achieves selective etching and profile control, enhancing the ability to manage complex materials and high aspect ratios in semiconductor manufacturing, thereby supporting the miniaturization and integration of semiconductor devices.
Implementation Method 1
applying a radio frequency (RF) signal to the plasma processing system at a first power level, applying the RF signal to the plasma processing system at a second power level, and applying the RF signal to the plasma processing system at a third power level
Data Source
AI summary
A method of etching a substrate is described. The method includes disposing a substrate having a surface exposing a first material and a second material in a processing space of a plasma processing system, and performing a modulated plasma etching process to selectively remove the first material at a rate greater than removing the second material. The modulated plasma etching process comprises a power modulation cycle having sequential power application steps that includes: applying a radio frequency (RF) signal to the plasma processing system at a first power level, applying the RF signal to the plasma processing system at a second power level, and applying the RF signal to the plasma processing system at a third power level. Thereafter, the power modulation cycle is repeated at least one more cycle, wherein each modulation cycle includes a modulation time period.