Temperature Controlled Dielectric Window for Plasma Chamber
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The brittle ceramic window in inductively coupled plasma (ICP) chambers experiences thermal stress due to non-uniform heat flux and high RF power, limiting the control of plasma processing conditions.
Innovation Solution
A liquid circulating system is implemented within the dielectric window, featuring multiple channels with independent temperature control, using a closed loop system with heat exchangers to circulate hot and cold liquids, allowing for precise temperature adjustment and uniform heat distribution across the window surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF power is increased to improve plasma processing capability, then processing efficiency is improved, but thermal stress in the ceramic window increases due to non-uniform heat flux
Solution Approach 1:
The ceramic window is divided into multiple temperature zones with independent heating and cooling channels. Each zone can be controlled separately to manage heat distribution, preventing excessive thermal stress while maintaining high RF power for efficient plasma processing.
Solution Approach 2:
Different regions of the ceramic window are provided with different thermal management characteristics through localized heating and cooling channels. This allows uniform temperature distribution across the window surface, reducing thermal stress while enabling high power operation for improved processing efficiency.
2Stress or pressure
If uniform temperature distribution is achieved to reduce thermal stress, then thermal stress is reduced, but system complexity increases due to multiple independent temperature control channels
Solution Approach 1:
Multiple heating channels and cooling channels are integrated into a unified temperature control system with centralized control logic. This merging approach maintains the ability to provide uniform temperature distribution across different zones while reducing overall system complexity through shared control infrastructure.
Solution Approach 2:
The temperature control system is designed with multi-functional components that can serve multiple purposes. The same heating and cooling infrastructure is used to achieve both uniform temperature distribution for stress reduction and localized temperature control for processing requirements, eliminating the need for separate control systems.
3Adaptability or versatility
If rapid temperature transients are implemented to improve processing flexibility, then processing adaptability is improved, but thermal stress increases due to rapid temperature changes
Solution Approach 1:
The ceramic window and its mounting structure are pre-heated to the target temperature before plasma processing begins. This preliminary heating action prevents sudden thermal shocks when plasma is ignited, allowing rapid switching between processing conditions while maintaining thermal stress within acceptable limits.
Solution Approach 2:
The temperature control system is designed to dynamically adjust heating and cooling rates based on real-time temperature measurements and processing requirements. This dynamic control enables rapid temperature transients for processing flexibility while managing the rate of change to prevent excessive thermal stress.
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 effectively reduces thermal stresses in the ceramic window, enables precise temperature control, and enhances the uniformity of heat flux, thereby improving the stability and efficiency of plasma processing without the need for local heaters or chillers, allowing for rapid and accurate temperature transients.
Implementation Method 1
a first heat exchanger connected to the source of cold liquid, the source of hot liquid and the inlet of the first channel such that the cold liquid passes through the first heat exchanger at a controllable flow rate and temperature of the hot liquid is adjusted by heat exchange with the cold liquid as the hot liquid passes through the first heat exchanger
Implementation Method 2
The liquid circulating system has a source of cold liquid circulating in a first closed loop which is not in fluid communication with the channels, a source of hot liquid circulating in a second closed loop which is in fluid communication with the channels
Data Source
AI summary
A temperature controlled dielectric window of an inductively coupled plasma processing chamber includes a dielectric window forming a top wall of the plasma processing chamber having at least first and second channels therein. A liquid circulating system includes a source of cold liquid circulating in a first closed loop which is not in fluid communication with the channels, a source of hot liquid circulating in a second closed loop which is in fluid communication with the channels, and first and second heat exchangers. The cold liquid passes through the first heat exchanger at a controllable flow rate and temperature of the hot liquid is adjusted by heat exchange with the cold liquid as the hot liquid passes through the first heat exchanger and then through the inlet of the first channel. The cold liquid passes through the second heat exchanger at a controllable flow rate and temperature of the hot liquid is adjusted by heat exchange with the cold liquid as the hot liquid passes through the second heat exchanger and then through the inlet of the second channel.