Plasma Processing Apparatus Refrigerating Cycle Temperature Control
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in achieving high temperature response and wide temperature setting ranges due to limitations in controlling the expansion valve opening degree and condenser heat exchange amount, leading to unstable sample stage temperatures.
Innovation Solution
A plasma processing method that incorporates a refrigerating cycle with a compressor, condenser, and first and second expansion valves, along with a vaporizer, where the flow rate and temperature of the refrigerant are controlled using rate flow valves, allowing for regulation of the sample stage temperature by adjusting the heat exchange amounts in the condenser and vaporizer, and maintaining specific valve openings to achieve a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a liquid refrigerant is used in a refrigerant supply apparatus with a tank and temperature regulation system, then the wafer surface temperature can be maintained constant, but the temperature response is slow and rapid temperature control is difficult
Solution Approach 1:
The patent uses refrigerant evaporation (liquid to gas phase transition) directly in the sample stage to achieve cooling. The refrigerant evaporates inside the sample stage, absorbing heat and providing rapid cooling response. This phase transition mechanism enables both rapid temperature control and effective heat exchange, resolving the contradiction between temperature stability and response speed.
2Speed
If the expansion valve opening degree is controlled to regulate refrigerant pressure and evaporation temperature, then rapid temperature control is achieved, but the temperature setting range is limited
Solution Approach 1:
The patent divides the temperature control function into two independent control mechanisms: expansion valve opening degree control for rapid response, and condenser heat exchange amount control for extending temperature range. By segmenting the control functions, the system achieves both rapid temperature control and wide temperature setting range without mutual interference.
Solution Approach 2:
The patent adds a new control dimension by controlling the condenser heat exchange amount in addition to the expansion valve opening degree. This transforms the single-dimension temperature control into a two-dimension control system, enabling wide temperature setting range while maintaining rapid response capability through the expansion valve.
3Device complexity
If the heat exchange amount in the condenser is not controlled, then the system is simpler, but the temperature setting range is limited and temperature control precision is reduced
Solution Approach 1:
The patent makes the condenser a controllable active component that serves dual purposes: maintaining refrigerant temperature and extending the temperature control range. By controlling the condenser heat exchange amount, the system achieves wide temperature setting range and high precision control without adding separate temperature regulation equipment.
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 rapid temperature control of the sample stage, providing a high temperature response and wide temperature setting range, effectively addressing the limitations of prior art by simultaneously controlling the expansion valve opening degree and condenser heat exchange amount.
Implementation Method 1
the refrigerant is evaporated in the refrigerant passage of the sample stage for cooling
Implementation Method 2
the use of refrigerant evaporation latent heat provides high cooling efficiency
Implementation Method 3
a compressor for highly pressurizing a refrigerant
Implementation Method 4
a condenser for condensing the highly pressurized refrigerant
Implementation Method 5
an expansion valve for expanding the refrigerant
Data Source
AI summary
A plasma processing apparatus includes: a refrigerating cycle including a refrigerant passage, a compressor, and a condenser, all of which are coupled in this order, and through which a refrigerant flows in this order, the refrigerant passage being disposed inside a sample stage and through which the refrigerant flows to serve as an evaporator; first and second expansion valves which are interposed between the condenser and the refrigerant passage and between the refrigerant passage and the compressor respectively in the refrigerating cycle; a vaporizer that is interposed between the second expansion valve and the compressor in the refrigerating cycle and which heats and vaporizes the refrigerant; and a controller which regulates opening and closing of the first and second expansion valves and regulates a refrigerant heat exchange amount of the condenser or vaporizer based on a refrigerant temperature between the condenser and the second expansion valve.