Substrate Support Feed-Forward Temperature Control
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Solution Overview
Problem
Substrate processing systems face challenges in maintaining consistent substrate temperatures due to disturbances from RF power variations, gas pressures, and other factors, leading to temperature fluctuations that affect etching performance.
Innovation Solution
A dynamic feed-forward control system that uses sensors to detect disturbances and generates compensation values to adjust heating elements and coolant flow rates, ensuring steady-state temperatures across the substrate support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feed-forward control based on RF power is implemented, then temperature consistency is improved, but system complexity increases
Solution Approach 1:
The system calculates compensation values based on RF power levels before temperature deviations occur. The feed-forward controller uses RF power measurements to proactively adjust heating element currents and coolant flow rates, preventing temperature fluctuations rather than reacting to them after they occur.
Solution Approach 2:
The patent introduces a feed-forward controller as an intermediary component that processes RF power signals and generates compensation values. This intermediary translates RF power variations into predictive temperature compensation actions, bridging the gap between RF power changes and temperature control responses.
2Manufacturing precision
If dynamic adjustment of heating elements and coolant flow is implemented, then temperature control precision is improved, but response time requirements increase
Solution Approach 1:
The system combines feed-forward control with feedback mechanisms by monitoring actual temperature deviations and using them to refine compensation values. The feedback controller adjusts heating element currents based on measured temperature differences, while the feed-forward component provides proactive adjustments based on RF power levels, creating a hybrid control system that achieves both precision and responsiveness.
Solution Approach 2:
The patent implements dynamic control by continuously adjusting heating element currents and coolant flow rates based on real-time RF power measurements and temperature readings. The system adapts its control actions dynamically rather than using fixed parameters, allowing it to respond effectively to varying process conditions.
Data Source
AI summary
A temperature controller is provided and includes interfaces, a compensation controller, summers, and a second controller. An interface receives a bias power signal and a plasma signal. The bias power signal indicates a bias RF power level of a RF generator. The plasma signal indicates a plasma RF power level of another RF generator. Another interface receives a temperature signal indicating a temperature of a substrate support. The compensation controller generates a compensation value based on a bias feed-forward transfer function and the bias RF power level and another compensation value based on a plasma feed-forward transfer function and the plasma RF power level. A summer generates an error signal based on a set point and the temperature. The second controller generates a control signal based on the error signal. Another summer controls an actuator to adjust the temperature based on the compensation values and the control signal.