Model-Based Pressure Control for Substrate Processing
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Solution Overview
Problem
Substrate processing systems face inefficiencies in transitioning between different chamber pressures and flow rates, leading to slowed processing and reduced throughput due to the need for stabilization, which is often hindered by the use of intermediate controllers and complex control approaches.
Innovation Solution
Implementing model-based pressure control methods that predetermine the relationship between chamber pressure and exhaust valve position as a function of process parameters, allowing for direct control of the exhaust valve to rapidly adjust pressure profiles and anticipate changes in processing conditions, thereby eliminating the need for intermediate controllers and enhancing system responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional separate control of chamber pressure and gas flow rate is used, then system stability is maintained, but processing speed and throughput are reduced due to stabilization wait times
Solution Approach 1:
The system performs preliminary action by pre-calculating the required exhaust valve position based on the desired pressure change and process parameter relationship before the actual pressure adjustment is needed. This allows the valve to be positioned optimally in advance, eliminating stabilization wait times during process transitions.
Solution Approach 2:
The system implements dynamic control by continuously adjusting the exhaust valve position based on real-time process parameters and pressure conditions. The model-based control algorithm dynamically determines valve positions to achieve target pressure changes while accounting for residence time effects, enabling faster and more efficient pressure transitions compared to static control methods.
2Speed
If model-based pressure control with direct exhaust valve positioning is implemented, then pressure stabilization speed is improved, but control system complexity increases
Solution Approach 1:
The system introduces a model-based control algorithm as an intermediary between the process parameters and exhaust valve control. This algorithm contains the predetermined relationship between pressure, process parameters, and valve position, serving as a mediator that translates process requirements into precise valve positioning commands without requiring complex real-time calculations or additional hardware controllers.
Solution Approach 2:
The system utilizes parameter changes by incorporating process parameters (such as gas flow rates, temperature, or other relevant variables) into the control model. The predetermined relationship allows the exhaust valve position to be adjusted based on changes in these parameters, enabling adaptive pressure control that responds to process conditions without increasing hardware complexity.
3Measurement precision
If intermediate controllers are used to manage pressure and flow transitions, then control precision is maintained, but system response time is reduced
Solution Approach 1:
The system extracts and eliminates intermediate controllers from the control architecture. By directly positioning the exhaust valve based on the model-based algorithm that accounts for process parameters and residence time effects, the system removes unnecessary control layers while maintaining pressure control precision through the sophisticated mathematical model that replaces the intermediate controllers.
Data Source
AI summary
Methods and apparatus are disclosed herein. In some embodiments, methods of controlling process chambers may include predetermining a relationship between pressure in a processing volume and a position of an exhaust valve as a function of a process parameter; setting the process chamber to a first state having a first pressure in the processing volume and a first value of the process parameter, wherein the exhaust valve is set to a first position based on the predetermined relationship to produce the first pressure at the first value; determining a pressure control profile to control the pressure as the process chamber is changed to a second state having a second pressure and a second process parameter value from the first state; and applying the pressure control profile to control the pressure by varying the position of the exhaust valve while changing the process chamber to the second state.