Placing Table Heat-Medium Switching for Stable Plasma Cleaning
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Solution Overview
Problem
The existing temperature control methods in plasma processing apparatuses face challenges in efficiently removing reaction products from the substrate and placing table surfaces, leading to increased cleaning time and potential apparatus breakdown due to temperature fluctuations and vaporization issues during dry cleaning processes.
Innovation Solution
A temperature control method that switches between low and high temperature heat mediums within the placing table's flow path, using a switchover process, ignition of cleaning plasma, and precise temperature control to stabilize the heat medium temperature, thereby optimizing the removal of reaction products without vaporizing the heat medium and maintaining efficient heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature is applied during cleaning to remove reaction products, then the removal rate of deposits is improved, but the heat medium may vaporize causing temperature fluctuations and apparatus breakdown
Solution Approach 1:
The patent dynamically changes the temperature parameter of the heat medium based on the cleaning process stage. During the heating phase, high temperature is applied to remove reaction products efficiently. During the cooling phase, the temperature is reduced to prevent vaporization. This parameter change resolves the contradiction by allowing high temperature benefits while avoiding its harmful effects through temporal separation.
Solution Approach 2:
The patent implements periodic heating and cooling cycles of the heat medium. The cleaning process uses periodic temperature variations where the heat medium is heated to high temperature for a specific duration to remove deposits, then cooled down to prevent vaporization. This periodic action allows the system to achieve high cleaning efficiency while maintaining temperature stability and preventing apparatus breakdown.
2Manufacturing precision
If the heat medium temperature is increased to improve reaction product removal, then the cleaning effectiveness is improved, but the cleaning time increases due to temperature control precautions
Solution Approach 1:
The patent applies preliminary cooling to the heat medium before the cleaning process begins. This preliminary action prepares the heat medium to absorb temperature during cleaning without immediately vaporizing, allowing for more effective and sustained high-temperature cleaning. The preliminary preparation prevents time loss during the cleaning process itself by avoiding temperature control interruptions.
Solution Approach 2:
The patent implements rapid cooling of the heat medium after the cleaning phase. By quickly reducing the temperature after deposits are removed, the system minimizes the time the heat medium remains at high temperature, preventing vaporization and associated delays. This rushing through the cooling phase reduces overall cleaning time while maintaining cleaning quality.
3Reliability
If continuous monitoring and control of heat medium temperature is implemented, then temperature stability is improved, but the device complexity increases
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the heat medium temperature and adjusts the heating/cooling rates accordingly. Temperature sensors provide real-time feedback to the control system, which then modulates the temperature control to maintain stability. This feedback mechanism achieves temperature stability without requiring overly complex control systems, as it uses straightforward proportional control based on temperature deviations.
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 method reduces cleaning time, improves throughput, and prevents apparatus structural issues by controlling the temperature to enhance the removal rate of reaction products while maintaining stable heat transfer, thus ensuring efficient operation of the plasma processing apparatus.
Implementation Method 1
a heat medium to be supplied into a flow path provided inside a placing table... configured to place a substrate thereon
Implementation Method 2
a cleaning process configured to remove a reaction product adhering to an electrostatic chuck... plasma is ignited by starting to supply a cleaning gas
Data Source
AI summary
A temperature control method includes a switchover process, an ignition process, a slope calculation process, a first and a second control processes. In the switchover process, a heat medium to be supplied into a flow path is switched from a heat medium of a first temperature supplied from a first temperature controller to a heat medium of a second temperature supplied from a second temperature controller. In the slope calculation process, a slope of temperature change of the heat medium is calculated based on a temperature of the heat medium at an outlet side of the flow path. In the first control process, the second temperature controller is controlled until the temperature of the heat medium is stabilized to a temperature lower than a set value. In the second control process, the second temperature controller is controlled such that the temperature of the heat medium reaches the set value.