Flow Ratio Controller Calibration for Etching Uniformity
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Solution Overview
Problem
Batch processing systems for semiconductor substrates face challenges in achieving uniform processing due to difficulty in controlling gas flow, leading to non-uniform processing, while single chamber systems have lower throughput.
Innovation Solution
The method involves splitting a single process gas supply into multiple inputs for separate process chambers, using a mass flow controller to calibrate a flow ratio controller, and applying span correction factors to ensure uniform gas flow, making the set points gas-independent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch processing systems are used to increase substrate throughput, then productivity is improved, but manufacturing precision deteriorates due to non-uniform processing
Solution Approach 1:
The patent divides the batch processing system into multiple independent process chambers (first etching chamber and second etching chamber), each capable of processing substrates independently with controlled gas flow. This segmentation allows parallel processing (improving throughput) while maintaining uniform processing conditions in each chamber (preserving precision).
Solution Approach 2:
The patent implements individual gas flow control for each process chamber using separate mass flow controllers and flow ratio controllers. Each chamber receives customized gas flow ratios optimized for its specific processing requirements, ensuring uniform processing locally in each chamber while maintaining high overall throughput through parallel operation.
2Manufacturing precision
If single chamber systems are used to achieve uniform processing, then manufacturing precision is improved, but productivity deteriorates due to sequential processing
Solution Approach 1:
The patent merges multiple single-chamber systems into a tandem configuration where multiple process chambers operate in sequence on the same substrate wafer. The substrate is processed in the first etching chamber, transferred, and then processed in the second etching chamber, achieving both uniform processing in each chamber and high throughput through sequential multi-step processing.
Solution Approach 2:
The patent implements continuous substrate processing through the tandem chamber system, where substrates move continuously from the first etching chamber to the second etching chamber without interruption. This continuous flow eliminates idle time between processing steps, maintaining high productivity while ensuring uniform processing conditions in each chamber.
3Manufacturing precision
If multiple mass flow controllers are used to control gas flow in each chamber, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a shared gas distribution system where a single process gas supply serves both etching chambers through a common gas panel. The flow ratio controller distributes gas to multiple chambers using standardized interfaces and control logic, reducing the need for duplicate mass flow controllers while maintaining precise flow control in each chamber through universal control mechanisms.
Solution Approach 2:
The patent introduces a flow ratio controller as an intermediary device between the mass flow controller and individual process chambers. This intermediary component manages gas distribution to multiple chambers, simplifying the overall system by centralizing flow control logic and reducing the number of independent mass flow controllers required while maintaining precise flow ratios in each chamber.
Data Source
AI summary
Embodiments of the present invention generally relate to methods of controlling gas flow in etching chambers. The methods generally include splitting a single process gas supply source into multiple inputs of separate process chambers, such that each chamber processes substrates under uniform processing conditions. The method generally includes using a mass flow controller as a reference for calibrating a flow ratio controller. A span correction factor may be determined to account for the difference between the actual flow and the measured flow through the flow ratio controller. The span correction factors may be used to determine corrected set points for each channel of the flow controller using equations provided herein. Furthermore, the set points of the flow ratio controller may be made gas-independent using additional equations provided herein.