Optical Plasma Ignition Within Skin Depth for Stable Pulsed Operation
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Solution Overview
Problem
Plasma treatment tools in integrated circuit fabrication face challenges in maintaining stable plasma ignition, particularly during transitions between E-mode and H-mode, and in pulsed operation modes, leading to inconsistent plasma performance and increased maintenance needs.
Innovation Solution
Incorporating an optical module with a laser to ignite the plasma, synchronized with electrical triggering signals, which provides a fast and stable method for plasma ignition, improving stability and reducing downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrical discharge is used for plasma ignition, then the system is simpler, but plasma stability deteriorates during mode transitions and pulsed operation
Solution Approach 1:
An optical ignitor is introduced as an intermediary component to mediate the plasma ignition process. The optical ignitor receives electrical triggering signals and converts them into optical energy that reliably ignites the plasma, even during mode transitions between E-mode and H-mode and in pulsed operation modes, thereby improving plasma stability without requiring fundamental changes to the overall system architecture
Solution Approach 2:
The conventional electrical discharge ignition system is replaced with an optical ignition system. Instead of using direct electrical discharge to ignite the plasma, the system uses an optical ignitor that converts electrical triggering signals into optical energy, which then ignites the plasma. This substitution provides more stable and predictable ignition characteristics
2Reliability
If laser-based optical ignitor is used, then plasma ignition stability improves, but device complexity increases
Solution Approach 1:
The optical ignitor is designed to perform multiple functions: it provides plasma ignition, serves as a synchronization reference for pulsed operation modes, and maintains stability during transitions between E-mode and H-mode. By consolidating these functions into a single component, the system achieves improved reliability without proportionally increasing overall system complexity
Solution Approach 2:
The system utilizes the laser's optical parameters (wavelength, pulse duration, energy) to achieve reliable plasma ignition under different operating conditions. By adjusting these parameters, the optical ignitor can adapt to mode transitions and pulsed operation requirements, providing stable ignition without requiring complex control mechanisms
3Reliability
If synchronized optical triggering is used, then plasma consistency improves, but operational complexity increases
Solution Approach 1:
The optical ignitor is synchronized with the electrical triggering signals through a feedback mechanism. The system monitors the triggering signals and adjusts the optical ignitor's operation accordingly, ensuring consistent plasma ignition timing. This feedback approach maintains plasma consistency while automating the synchronization process, reducing the burden on operators
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 use of a laser-based optical ignitor enhances plasma stability, consistency, and predictability, reducing maintenance and operational costs while improving etching performance and reducing substrate damage.
Implementation Method 1
An optical module with an optical ignitor, such as a laser, is used to ignite the process gas to form a plasma
Data Source
AI summary
Methods for plasma stability in a plasma treatment tool are disclosed. A laser is positioned within a plasma treatment chamber within a skin depth of the electromagnetic field generated therein. The laser can be synchronized with the electrical triggering signals that generate the electromagnetic field. This scheme provides a stable and efficient method of plasma ignition.