Plasma Processing Apparatus Coolant Flow Reversal
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in promptly controlling the temperature of substrates during plasma processes due to complex configurations and prolonged temperature control times, especially when using coolant systems with multiple valves and heating units.
Innovation Solution
A plasma processing apparatus with a mounting table featuring multiple coolant paths, a check valve, and a reversing unit that allows for rapid temperature control by selectively reversing the flow direction of coolant through these paths, simplifying the configuration and reducing control time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple opening/closing valves are provided at coolant paths to control temperature distribution, then temperature control capability is improved, but device complexity increases
Solution Approach 1:
The mounting table is divided into multiple temperature control regions (central region and peripheral region), each with dedicated coolant paths. This segmentation allows independent temperature control of different regions without requiring multiple valves, as each region has its own dedicated cooling circuit.
Solution Approach 2:
Instead of using multiple valves to control coolant flow distribution, the patent inverts the approach by providing dedicated coolant paths for different regions. The flow distribution is controlled by the path configuration itself rather than by valve operations, simplifying the system while maintaining temperature control capability.
2Temperature
If a heating unit is provided in addition to the chiller unit to heat cooled coolant, then temperature control range is improved, but temperature control time increases
Solution Approach 1:
The patent employs periodic reversal of coolant flow direction through the check valve mechanism. By alternately allowing coolant to flow in different directions, the system achieves both cooling and heating effects over time, expanding the temperature control range without requiring a separate heating unit, thus avoiding additional time delays.
Solution Approach 2:
The coolant system serves dual purposes (heating and cooling) through flow direction reversal. The coolant that has been cooled by the chiller unit can subsequently heat the mounting table when flow direction is reversed, making the system self-sufficient and eliminating the need for a separate heating unit, thereby reducing temperature control time.
3Temperature
If coolant paths are formed in central and periphery regions with separate valve control, then temperature distribution control is improved, but ease of operation deteriorates
Solution Approach 1:
The mounting table is segmented into central and peripheral regions with dedicated coolant paths for each region. This physical segmentation of the cooling system allows each region to be controlled independently through its own path configuration, simplifying operation compared to using multiple valves to control a shared coolant path.
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
Enables prompt and precise temperature control of substrates during plasma processes, optimizing conditions for each process step by selectively routing coolant flow through various paths within the mounting table.
Implementation Method 1
a check valve provided at a part of the multiple number of coolant paths
Implementation Method 2
a reversing unit configured to reverse a flow direction of the coolant that flows and circulates through the multiple number of coolant paths
Implementation Method 3
a temperature controller configured to control a temperature of a coolant flown and circulated through the multiple number of coolant paths
Implementation Method 4
a plasma generating device configured to supply electromagnetic energy such as a microwave or a RF wave
Implementation Method 5
a bias voltage applying device configured to apply a bias voltage to the mounting table and accelerate ions in the plasma toward the processing target substrate
Data Source
AI summary
A plasma processing apparatus includes a lower electrode 12 on which a wafer W is provided. A second coolant path 70b is formed in a spiral shape in a region within the lower electrode 12 corresponding to where the wafer W is placed. Further, a first coolant path 70a is formed in a spiral shape to be located in a lower region within the lower electrode 12 corresponding to where the second coolant path 70b is formed. A pipeline 72 connected to a chiller unit 71 is branched into a first pipeline 72a connected to the first coolant path 70a and a second pipeline 72b connected to the second coolant path 70b. A check valve 90 allowing a coolant to flow in one direction is provided on the first pipeline 72a, and a reversing unit 92 reversing a flow direction of the coolant is provided on the pipeline 72.