Remote Plasma Pulsing via Pressure Control
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Solution Overview
Problem
Remote plasma systems face low throughput and instability due to the need for lengthy pre-ignition steps and sensitivity to gas flow and pressure variations, which can extinguish the plasma when pulsing excited species to a reaction chamber.
Innovation Solution
A remote plasma system with a pressure control device and a control valve that maintains steady-state conditions by controlling the operating pressure and flow rates, allowing for pulsing of excited species without turning the power on and off, using a closed-loop pressure controller and fast-response pneumatic valve to ensure continuous plasma operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If power is pulsed to the remote plasma source to provide excited species, then excited species are provided to the reaction chamber, but the plasma requires lengthy pre-ignition steps and has low throughput
Solution Approach 1:
The system performs preliminary action by maintaining the plasma in a continuous steady-state condition before excited species are needed. The plasma is pre-established and kept ready, eliminating the need for lengthy pre-ignition steps before each pulse. This allows excited species to be provided on-demand without sacrificing throughput.
2Quantity of substance
If gas flow is diverted from the reactor to a vacuum source or bypass to pulse excited species, then excited species are pulsed to the reaction chamber, but the plasma characteristics change or the plasma extinguishes
Solution Approach 1:
The system segments the gas flow paths by introducing a separate extraction port that is distinct from the main reactor inlet. This allows excited species to be extracted through a dedicated pathway without disrupting the main gas flow to the plasma source. The segmentation enables independent control of species extraction while maintaining plasma stability.
Solution Approach 2:
The system uses an intermediary mechanism by introducing a controlled valve and pressure control device as mediators between the plasma source and the reaction chamber. These intermediaries allow precise regulation of gas flow and pressure, enabling excited species to be pulsed without causing abrupt changes that would extinguish the plasma. The intermediaries buffer the interaction between species extraction and plasma maintenance.
3Quantity of substance
If gas flow rate or pressure varies during pulsing, then excited species are delivered to the reaction chamber, but the plasma characteristics change significantly
Solution Approach 1:
The system implements feedback control by using a pressure control device that continuously monitors and adjusts the pressure in the species extraction region. This feedback mechanism ensures that pressure variations are compensated in real-time, maintaining consistent plasma characteristics during excited species delivery. The feedback loop prevents drift in plasma parameters that would otherwise occur during pulsing operations.
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 increases throughput and maintains uniformity of activated species, preventing plasma extinction and enhancing the efficiency of processes like deposition, etching, and surface treatment.
Implementation Method 1
remote plasma can generate excited reactive species at relatively low temperatures, allowing reactions to take place at effectively lower temperatures
Implementation Method 2
control a pressure at the remote plasma unit as the excited species are pulsed to the reaction chamber
Implementation Method 3
a control valve between the remote plasma unit and the reaction chamber to pulse species from the remote plasma unit to the reaction chamber
Data Source
AI summary
A system and method for providing pulsed excited species from a remote plasma unit to a reaction chamber are disclosed. The system includes a pressure control device to control a pressure at the remote plasma unit as reactive species from the remote plasma unit are pulsed to the reaction chamber.