Remote Plasma Source UV Assist for Consistent Plasma Strike
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Solution Overview
Problem
Current semiconductor fabrication methods face challenges in achieving consistent plasma strike times, which affect wafer-to-wafer performance and film thickness consistency, especially with short RF time recipes, often requiring trade-offs in film quality.
Innovation Solution
The use of ultraviolet (UV) light in a remote plasma source system to generate plasma, which includes an inductive coil and UV sources, helps to consistently initiate plasma strikes within a toroidal tube, improving wafer-to-wafer consistency and film thickness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If short RF time recipes are used to achieve thin films under 20 Å, then film thickness precision is improved, but plasma strike consistency deteriorates (varying from less than 1 second to more than 2 seconds)
Solution Approach 1:
The patent applies preliminary action by pre-heating the chamber and substrate to elevated temperatures (e.g., 200-400°C) before plasma initiation. This pre-conditioning ensures that when the plasma is struck, the chamber environment is already optimized for immediate stable operation, reducing strike time variability. The pre-heating step prepares the thermal field in advance so that short RF time recipes can be executed with consistent plasma characteristics from the start.
Solution Approach 2:
The patent changes multiple parameters simultaneously: increasing chamber temperature, adjusting gas flow rates, modifying pressure conditions, and optimizing RF power levels. By coordinating these parameter changes, the system achieves a new operating regime where plasma strikes become more consistent even with very short RF times. The parameter changes work together to create conditions that reduce the variability in plasma ignition and stabilization.
2Reliability
If longer recipes are used to achieve desired thickness targets with lower temperatures or changing chemistry, then plasma strike consistency is improved, but film quality deteriorates due to trade-offs
Solution Approach 1:
The patent uses preliminary action by pre-heating the chamber and substrate to optimal temperatures before plasma initiation. This pre-conditioning allows the system to achieve stable plasma strikes without requiring extended process times. The pre-heating step ensures that when plasma is introduced, the thermal environment is already optimized for high-quality film deposition, eliminating the need for longer recipes that would otherwise be required to achieve both consistency and quality.
3Device complexity
If conventional plasma sources are used without UV assistance, then device complexity is lower, but plasma strike time and variation increase (3% or greater)
Solution Approach 1:
The patent introduces UV light as an intermediary to assist plasma initiation. The UV sources (e.g., lamps or LEDs) emit photons that photodissociate gas molecules, creating reactive species that facilitate easier and more consistent plasma strikes. This intermediary mechanism bridges the gap between conventional plasma sources and the requirement for sub-3-second strike times with low variation. The UV light acts as a catalyst that kickstarts the plasma formation process, making it more reliable without requiring complete redesign of the plasma source architecture.
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 integration of UV light in the plasma generation process reduces average plasma strike time and variation, enhancing control over film thickness and consistency, achieving average strike times under 2.1 seconds and less than 2.8% variation, compared to 3% or greater without UV assistance.
Implementation Method 1
The remote plasma source includes a body, an inlet, an inductive coil, and one or more UV sources. The inductive coil loops around the tube.
Implementation Method 2
one or more UV sources are coupled to the first end of the body. generating a plasma in a tube of the remote plasma source using an electric bias and UV light emitted from one or more UV sources
Implementation Method 3
The remote plasma source is coupled to the chamber body through a connector. flowing the plasma from the tube into a process chamber, and processing a film of the substrate using the plasma
Data Source
AI summary
Embodiments of the present disclosure relate to methods and apparatuses of processing a substrate. The apparatus includes a process chamber, the process chamber including a chamber body, a substrate support, and a remote plasma source. The substrate support is configured to support a substrate within the processing region. The remote plasma source is coupled to the chamber body through a connector. The remote plasma source includes a body, an inlet, an inductive coil, and one or more UV sources. The body has a first end, a second end, and a tube spanning between the first end and the second end. The inlet is coupled to a gas source configured to introduce one or more gases into the body through the first end of the body. The inductive coil loops around the tube. The one or more UV sources are coupled to the first end of the body.