Plasma Processing Apparatus Viewing Window Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma processing apparatuses face precision issues in temperature detection due to the influence of electromagnetic waves emitted by the viewing window, leading to inaccurate temperature measurement and reduced detection precision.
Innovation Solution
A plasma processing apparatus with an additional viewing window cooled to room temperature is used to reduce and stabilize electromagnetic waves emitted from the viewing window, allowing for precise temperature monitoring and control by correcting the electromagnetic wave values, thereby increasing measurement precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a viewing window is disposed between the radiation thermometer and the target member to allow infrared rays to pass through, then contactless temperature detection becomes possible, but the viewing window itself emits electromagnetic waves that interfere with the detection precision
Solution Approach 1:
A cold shield is introduced as an intermediary component between the radiation thermometer and the viewing window. This cold shield is maintained at a lower temperature than the viewing window, causing it to emit fewer electromagnetic waves. The cold shield selectively blocks the electromagnetic waves from the viewing window while allowing infrared rays from the target member to pass through, thereby resolving the interference issue.
Solution Approach 2:
The temperature parameter of the viewing window is changed by introducing a cooling mechanism. By actively cooling the viewing window to reduce its temperature, the emission of electromagnetic waves from the viewing window is minimized. This parameter change directly addresses the harmful electromagnetic wave emission while maintaining the viewing window's primary function.
2Measurement precision
If the viewing window is cooled to room temperature to reduce electromagnetic wave emission, then detection precision improves, but additional cooling mechanisms and system complexity are required
Solution Approach 1:
Rather than cooling the entire viewing window system, a cold shield is introduced as a simpler intermediary component. This cold shield is positioned between the thermometer and the viewing window, and it is cooled to a moderate temperature to reduce its own electromagnetic wave emission. This approach achieves the precision improvement with less system complexity than cooling the entire viewing window assembly.
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 solution stabilizes electromagnetic waves emitted from the viewing window, enhancing the precision of temperature monitoring and control, leading to more stable plasma processing and improved dimensional precision in semiconductor etching.
Implementation Method 1
temperature of the inner wall surface members is detected by an infrared thermometer via the window to control the temperature of plasma-tolerant walls with high precision
Implementation Method 2
When the viewing window receives heat through radiation or conduction to be heated and temperature thereof goes up, members of the viewing window emit electromagnetic waves such as infrared rays and far-infrared rays
Implementation Method 3
A plasma processing apparatus with an additional viewing window cooled to room temperature is used to reduce and stabilize electromagnetic waves emitted from the viewing window
Data Source
AI summary
In a plasma processing apparatus, an additional viewing window is disposed between an infrared temperature sensor and a view window, and the additional viewing window is cooled to be retained at room temperature (20° C. to 25° C.), to reduce and to stabilize electromagnetic waves emitted from the viewing window. By correcting the value of the electromagnetic waves, the measurement precision of the temperature monitor is increased and it is possible to measure and to control the dielectric window temperature in a stable state.