Plasma Processing Apparatus Refrigerant Temperature Control
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Solution Overview
Problem
Existing plasma processing techniques face challenges in rapidly and accurately adjusting the temperature of semiconductor wafers due to the large heat capacity of refrigerants and inefficient heat transfer, which is exacerbated by increasing heat input and complex semiconductor structures, leading to difficulties in achieving uniform temperature distributions and efficient temperature control.
Innovation Solution
A plasma processing apparatus with concentric refrigerant channels and a direct expansion-type refrigerant temperature adjustment system, utilizing upstream and downstream expansion valves to control refrigerant flow rates and pressures, ensuring no change in flow rate between expansion valves, and incorporating a refrigeration cycle with a compressor, condenser, and evaporator to maintain consistent refrigerant temperatures and achieve uniform temperature distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large quantity of refrigerant is used for temperature adjustment, then the temperature of the sample can be maintained constant, but the temperature cannot be changed promptly
Solution Approach 1:
The refrigerant system is segmented into multiple channels (first refrigerant channel and second refrigerant channel) with independent flow control. This allows selective cooling of different regions without requiring large quantities of refrigerant throughout the entire system, enabling both stability and responsiveness.
Solution Approach 2:
The invention introduces dynamic flow rate control for each refrigerant channel independently. By adjusting the flow rate of refrigerant in each channel according to real-time temperature requirements, the system can rapidly respond to temperature changes while maintaining stability when needed.
2Device complexity
If heat transfer is performed only by means of heat transfer between liquid refrigerant and channels, then the system is simple, but the temperature change is slow
Solution Approach 1:
The invention utilizes phase transition of refrigerant (liquid to gas) within the channels to enhance heat transfer efficiency. The refrigerant evaporates inside the channels, absorbing large amounts of heat through latent heat of vaporization, which dramatically increases the temperature adjustment speed while maintaining relatively simple system structure.
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 configuration allows for efficient and precise temperature control of the sample stage, preventing dry-out and maintaining consistent refrigerant temperatures, enabling rapid and accurate adjustment of temperatures and distributions, even under high heat input conditions, thus improving the quality of plasma processing.
Implementation Method 1
a liquid refrigerant is made to flow in the channels to adjust the temperature of the sample stage by means of heat transfer
Implementation Method 2
the refrigerant is brought to boiling and evaporated in refrigerant channels in the sample stage
Implementation Method 3
use evaporative latent heat of the refrigerant in a gas-liquid two-phase flow state for heat exchange
Data Source
AI summary
A plasma processing method is provided for a plasma processing apparatus which includes a plurality of upstream-side expansion valves and a plurality of downstream-side expansion valves connected to respective refrigerant inlets and respective refrigerant outlets to adjust a flow rate or a pressure of a refrigerant flowing into the respective refrigerant inlets and a flow rate or a pressure of a refrigerant flowing out from the respective refrigerant outlets. The method includes adjusting openings of the upstream-side expansion valves and openings of the downstream-side expansion valves so that no change in flow rate of the refrigerant occurs in a plurality of refrigerant channels between the plurality of upstream-side expansion valves and the plurality of downstream-side expansion valves via the plurality of refrigerant channels in a refrigeration cycle allowing the refrigerant to flow therein.