Mixed-Gas Plasma Source Flow Control for Precise Partial Pressure
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Solution Overview
Problem
Existing charged particle beam systems face challenges in dynamically controlling the ratio of gas species in plasma sources, leading to inconsistent and wasteful gas mixture adjustments, particularly when milling diverse sample materials.
Innovation Solution
The system employs individual controllers and capillary constrictions to precisely control the flow rate and partial pressure of each gas species, allowing for real-time adjustments without evacuating the entire gas supply line, thereby minimizing waste and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single gas supply line is used for multiple gas species, then the system structure is simplified, but the control precision of partial pressure and flow rate for each gas species deteriorates
Solution Approach 1:
The patent divides the gas supply system into separate supply lines for each gas species (first gas supply line for first gas, second gas supply line for second gas). Each supply line has its own flow controller, allowing independent control of flow rate and partial pressure for each gas species without interference from others, thus resolving the contradiction between system simplicity and control precision.
2Productivity
If gas flow rate is increased to improve mixing speed, then the response time is reduced, but the gas waste increases
Solution Approach 1:
The patent incorporates flow controllers in each gas supply line that can precisely control and regulate the flow rate of each gas species. This feedback control mechanism allows the system to achieve fast mixing speeds when needed while automatically reducing flow rates when lower speeds suffice, thereby optimizing the balance between productivity and gas consumption, and reducing waste.
3Reliability
If the entire gas supply line is evacuated when switching gas species, then complete gas replacement is achieved, but the time consumption and gas waste increase
Solution Approach 1:
The patent extracts the gas replacement process from the entire supply line and confines it to only the plasma source chamber and immediately connected portions. By using separate supply lines with individual flow controllers, the system can isolate and evacuate only the necessary sections when switching gas species, achieving complete replacement at the plasma source while minimizing evacuation time and gas waste in the rest of the supply system.
4Device complexity
If manual control of gas mixing is used, then the system complexity is reduced, but the operational precision and efficiency deteriorate
Solution Approach 1:
The patent replaces manual mechanical control with automated electronic flow controllers that receive signals from a computer system. Each flow controller electronically regulates the flow rate of its corresponding gas species based on programmed parameters, providing precise control of gas mixtures without requiring manual intervention. This substitution maintains relatively simple hardware while dramatically improving operational precision and efficiency.
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 enables precise and dynamic control of gas mixtures, optimizing milling processes by reducing gas waste and time, and minimizing inconsistencies in gas delivery.
Implementation Method 1
a first capillary constriction including a first end fluidly coupled to the first controller and a second end fluidly coupled to the plasma source chamber
Implementation Method 2
configured to control a first flow rate of the first gas... configured to control a second flow rate of the second gas
Implementation Method 3
ions are generated by ionizing a gas in a plasma source
Data Source
AI summary
An ion beam system including a plasma source tube defining a plasma source chamber, a first gas reservoir housing a first gas, a second gas reservoir housing a second gas, a first controller fluidly coupled to the first gas reservoir and configured to control a first flow rate of the first gas, and a second controller fluidly coupled to the second gas reservoir and configured to control a second flow rate of the second gas. The system also includes a first capillary constriction including a first end fluidly coupled to the first controller and a second end fluidly coupled to the plasma source chamber, and a second capillary constriction including a third end fluidly coupled to the second controller and a fourth end fluidly coupled to the plasma source chamber, where the first capillary constriction and the second capillary constriction are distinct.