Plasma Chamber Showerhead Temperature Control via Dynamic Coolant Bypass
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Solution Overview
Problem
Plasma processing in semiconductor fabrication leads to temperature overshoots in components like the showerhead, causing inefficiencies and quality degradation, and existing solutions for improving heat control are costly and inefficient.
Innovation Solution
A temperature regulation system for plasma-enhanced process chambers using a heat exchanger with a chiller and a flow bypass kit, allowing for dynamic coolant flow rates and on/off flow control valves to manage heat effectively during idle and processing modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the coolant temperature is lowered to increase cooling capacity, then the cooling effect is improved, but the system complexity and cost increase due to requiring larger heaters and major tool redesign
Solution Approach 1:
The patent implements dynamic coolant flow rate adjustment through a bypass valve system that allows the cooling system to adapt between idle and processing modes. During idle mode, coolant flows through the heat exchanger at a higher rate to maintain lower temperatures with minimal heater power. During processing mode, the bypass valve redirects coolant flow to reduce cooling capacity and prevent temperature overshoot, eliminating the need for oversized heaters and major tool redesign
Solution Approach 2:
The system changes the coolant flow rate parameter dynamically based on operational mode. A bypass valve controls the ratio of coolant flowing through the heat exchanger versus bypassing it, allowing continuous adjustment of cooling capacity. This parameter change enables the same cooling system to serve both idle and processing modes effectively without requiring different hardware configurations
2Temperature
If the coolant flow rate is increased to prevent temperature overshoot during processing, then temperature control is improved, but the cooling efficiency during idle mode decreases
Solution Approach 1:
The bypass valve system dynamically adjusts coolant flow distribution based on operational mode. During idle mode, the valve directs maximum coolant flow through the heat exchanger for efficient cooling with minimal energy input. During processing mode, the valve bypasses a portion or all of the coolant flow around the heat exchanger, reducing cooling capacity to match the increased heating load from plasma and prevent temperature overshoot
3Stability of the object's composition
If a larger heater is provided to maintain constant temperature during idle mode with lowered coolant temperature, then temperature stability is improved, but the device complexity and cost increase due to major tool redesign
Solution Approach 1:
Instead of using a larger heater, the system dynamically adjusts coolant flow rate to match heating demands. During idle mode, high coolant flow through the heat exchanger provides sufficient cooling with a small heater. During processing mode, the bypass valve reduces coolant flow to match the increased heating load from plasma, maintaining temperature stability without requiring heater upgrades or major tool redesign
Solution Approach 2:
The bypass valve acts as an intermediary control element that regulates the interaction between the cooling system and the process chamber. By controlling coolant flow distribution, it mediates the balance between heating and cooling loads, enabling temperature stability across different operational modes without modifying the heater or chamber 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 solution efficiently regulates component temperatures, preventing overshoots and minimizing process delays, while being cost-effective and easily retrofittable to existing chambers, thus enhancing semiconductor processing quality.
Implementation Method 1
a heat exchanger is configured to remove heat from the component
Implementation Method 2
providing a coolant at a first flow rate to the heat exchanger
Data Source
AI summary
Methods and apparatus for regulating the temperature of a component in a plasma-enhanced process chamber are provided herein. In some embodiments, an apparatus for processing a substrate includes a process chamber and an RF source to provide RF energy to form a plasma in the process chamber. A component is disposed in the process chamber so as to be heated by the plasma when formed. A heater is configured to heat the component and a heat exchanger is configured to remove heat from the component. A chiller is coupled to the heat exchanger via a first flow conduit having an on/off flow control valve disposed therein and a bypass loop to bypass the flow control valve, wherein the bypass loop has a flow ratio valve disposed therein.