Wafer Support Heater Control for Faster Temperature Stabilization
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Solution Overview
Problem
The temperature of the wafer support in semiconductor processing apparatuses takes a significant amount of time to stabilize, and fluctuations in temperature due to disturbances can degrade process results and yield.
Innovation Solution
Implementing iterative learning-based feedforward and feedback controls to determine heater power for stabilizing and maintaining the temperature of the wafer support within a target range during semiconductor processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional temperature control methods are used, then the wafer support temperature can be controlled, but the temperature takes considerable time to stabilize and fluctuates due to disturbances
Solution Approach 1:
The feedforward controller receives the temperature setting signal and generates a feedforward control signal in advance, before the temperature stabilization process begins. This preliminary action anticipates the required heater power adjustments needed to reach and maintain the target temperature, reducing the time required for temperature stabilization compared to conventional reactive control methods.
Solution Approach 2:
The feedback controller continuously receives the actual temperature measurement signal and generates a feedback control signal to correct temperature deviations. This closed-loop feedback mechanism ensures that temperature fluctuations due to disturbances are promptly detected and corrected, maintaining stable temperature control while reducing stabilization time.
2Reliability
If conventional temperature control methods are used, then basic temperature regulation is achieved, but temperature fluctuations due to disturbances degrade process results and yield
Solution Approach 1:
The feedback controller continuously monitors the actual temperature through the measurement signal and generates corrective control actions to eliminate temperature deviations caused by disturbances. This ensures high temperature stability and consistent process results throughout the semiconductor manufacturing process.
Solution Approach 2:
The iterative learning controller acts as an intermediary between the feedforward and feedback controllers, processing the temperature setting signal and measurement signal to optimize the control signal. This intermediary component enhances the overall control system's ability to maintain temperature stability and improve process reliability by learning from past performance and adapting to disturbance patterns.
3Device complexity
If simple control methods are used, then the control system is simple, but the temperature cannot be quickly stabilized and maintained within target range
Solution Approach 1:
The feedforward controller performs preliminary temperature control actions based on the setting signal before disturbances occur, enabling faster temperature stabilization. This proactive approach reduces the time required to reach target temperature compared to simple reactive control systems.
Solution Approach 2:
The feedback controller provides continuous temperature monitoring and correction, ensuring the temperature is quickly stabilized and maintained within the target range. The combination of feedforward and feedback control creates a more responsive system than simple control methods while maintaining reasonable complexity.
4Manufacturing precision
If iterative learning-based feedforward and feedback controls are implemented, then temperature stabilization speed and accuracy improve, but the control system complexity increases
Solution Approach 1:
The feedforward controller uses the temperature setting signal to generate advance control actions, improving temperature control precision by anticipating required adjustments before disturbances occur. This preliminary action reduces temperature deviations and improves manufacturing precision.
Solution Approach 2:
The feedback controller continuously corrects temperature deviations using the measurement signal, ensuring high temperature control precision. The iterative learning controller processes both feedforward and feedback signals to optimize control accuracy, achieving superior temperature control precision despite increased system complexity.
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
Stable temperature control improves process results and enhances yield by maintaining consistent performance across semiconductor processing apparatuses.
Implementation Method 1
a heater power supply configured to supply heater power to the heater to control a temperature of the wafer support
Data Source
AI summary
A semiconductor processing apparatus may include a wafer support including a heater; a heater power supply configured to supply heater power to the heater; and a processor configured to receive a setting signal indicating a set temperature of the wafer support, determine the heater power using the setting signal, receive a measurement signal obtained by measuring the temperature of the wafer support, generate an error signal based on the setting signal and the measurement signal, generate a feedforward signal based on the setting signal, generate an iterative learning signal based on the error signal, generate a feedback signal based on the error signal, determine a control signal based on the feedforward, iterative learning, and feedback signals, output the control signal to the heater power supply, and determine the heater power in a sampling period of the measurement signal being within a target range as a final heater power.