Substrate Processing Feedback Control for Film Thickness Drift
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Solution Overview
Problem
The substrate processing apparatus experiences fluctuations in processing results over time due to changes in thermal emissivity of the susceptor cover, affecting film thickness consistency.
Innovation Solution
A system comprising a transfer chamber, process chamber, mass measurer, calculator, determinator, setter, and controller that measures substrate mass before and after processing, calculates film thickness, determines abnormality, and adjusts process conditions to maintain consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a susceptor cover with heater is used in the substrate processing apparatus, then the substrate can be heated for processing, but the thermal emissivity of the susceptor cover changes over time causing film thickness to increase and processing results to fluctuate
Solution Approach 1:
The system measures the actual film thickness formed on the substrate and feeds this information back to the controller. The controller then adjusts the process conditions (such as processing time, temperature, or gas flow rate) based on this feedback to compensate for changes in thermal emissivity of the susceptor cover, thereby maintaining consistent film thickness despite aging effects
Solution Approach 2:
The system dynamically changes process parameters (processing conditions) based on the measured film thickness. When the film thickness deviates from the target value, the controller modifies parameters such as processing time, temperature, or reactive gas flow rate to correct the deviation and achieve the desired film thickness consistency
2Productivity
If the substrate processing is performed repeatedly over time, then productivity increases, but the thermal emissivity changes cause processing results to fluctuate and film thickness to increase
Solution Approach 1:
The feedback mechanism continuously monitors film thickness after each processing cycle and adjusts subsequent process conditions accordingly. This allows the system to maintain high productivity by processing substrates continuously while compensating for thermal emissivity changes that occur with repeated use, preventing film thickness drift
Solution Approach 2:
The system performs self-adjustment by automatically measuring its own processing output (film thickness) and correcting its process conditions without external intervention. This self-service capability enables the system to maintain consistent quality over extended operation periods while sustaining high productivity
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 ensures consistent film thickness by automatically correcting process conditions when abnormalities are detected, mitigating the impact of thermal emissivity changes in the susceptor cover.
Implementation Method 1
a measurer configured to measure a mass of the substrate
Data Source
AI summary
To suppress fluctuations in substrate processing results over time due to operations of a substrate processing apparatus, there is provided a technique that includes: a transfer chamber where a substrate is transferred; a process chamber in which the substrate is processed under process conditions of the substrate; a measurer for measuring a mass of the substrate before the processing of the substrate starts and after the processing of the substrate ends; a calculator for calculating a film thickness value of the substrate from a difference in the mass measured by the measurer before the processing starts and after the processing ends; a determinator for determining whether the film thickness value calculated by the calculator is abnormal; a setter for setting the process conditions; and a controller for controlling the setter to change the process conditions when the determinator determines that the film thickness value is abnormal.