Flow Ratio Controller with Hybrid Channel MFC Verification
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Solution Overview
Problem
Existing methods for calibrating process chambers in semiconductor manufacturing, such as chamber rate of rise and common flow verification systems, suffer from inaccuracies due to chamber volume variations, hardware additions, long setup times, and increased costs, hindering consistent production of semiconductor devices.
Innovation Solution
A flow ratio controller system with a hybrid distribution channel and a controller that operates in alternative control modes, performing rate-of-pressure-change tests to calculate calibrated values for reference and target channels, allowing for parallel verification and control of mass flow meters across multiple chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a common flow verification system is used to verify MFC flow rates, then measurement precision is improved, but device complexity increases due to additional hardware and plumbing
Solution Approach 1:
The patent introduces a intermediary flow verification system that uses a common flow path and timing mechanism to verify MFC flow rates without requiring separate verification hardware for each MFC. The system uses a flow verifier that can sequentially receive flow from multiple MFCs through a common path, with isolation valves acting as intermediaries to control which MFC flows to the verifier at any given time.
Solution Approach 2:
The flow verification system is designed as a universal platform that can verify the flow rates of multiple different MFCs using the same hardware infrastructure. The common flow path, combined with isolation valves and a single flow verifier, allows one verification system to serve multiple MFCs, eliminating the need for dedicated verification hardware for each MFC.
2Measurement precision
If a common flow verification system with extended plumbing is used, then measurement precision is improved, but loss of time increases due to long time of flight
Solution Approach 1:
The flow verification process is segmented into discrete sequential steps for each MFC, with isolation valves enabling clear separation between verification cycles. Each MFC verification is a distinct segment that can be completed independently, allowing the system to methodically verify each MFC without interference from others, thus optimizing the time required for each verification segment.
3Measurement precision
If a common flow verification system is used, then measurement precision is improved, but productivity decreases due to serial verification requirement
Solution Approach 1:
The flow verification system is designed to be dynamically reconfigurable through the use of isolation valves that can quickly switch which MFC is connected to the flow verifier. This dynamic switching capability allows the system to adapt its configuration for each verification cycle, enabling efficient sequential verification of multiple MFCs without requiring physical reconfiguration of the entire system.
4Ease of operation
If chamber rate of rise method is used for MFC calibration, then ease of operation is improved, but manufacturing precision deteriorates due to chamber volume variations
Solution Approach 1:
Instead of relying on chamber-specific characteristics that vary between chambers, the invention uses a standardized flow verification approach where the flow verifier creates a controlled, repeatable measurement environment. The system copies the ideal verification conditions across all MFC verifications, using the same flow path, same measurement methodology, and same reference standards, thereby eliminating the precision problems caused by chamber variations.
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
Enhances process control efficiency, reduces setup time, and improves throughput by enabling parallel MFC verification, ensuring consistent and reliable semiconductor device production with reduced hardware costs and extended monitoring capabilities.
Implementation Method 1
perform a first rate-of-pressure-change test on a first target flow path that extends from the inlet through a reference volume to the hybrid distribution channel, using measurements from a mass flow meter in the hybrid distribution channel
Implementation Method 2
By incorporating temperature measurements and the rate of pressure rise, and applying the Ideal Gas Law equation, the mass flow can be calculated
Implementation Method 3
Each of the plurality of distribution channels is provided with a respective flow control valve and configured to carry a respective portion of the total inlet fluid flow
Data Source
AI summary
A flow ratio controller system includes an inlet receiving a total inlet fluid flow from one or more inlet channels, distribution channels fluidically connected to the inlet and arranged in parallel in a branching flow path downstream of the inlet, and a controller. The distribution channels includes a hybrid distribution channel. The controller selectively operates in alternative control modes including a flow verification control mode and a flow ratio control mode. In the flow verification control mode, the controller calculates a calibrated value for a reference volume using measurements from a mass flow meter in the hybrid distribution channel, then calculates a target channel calibration value for the mass flow meter in the target distribution channel. In the flow ratio control mode, the controller controls each of the distribution channels, including the hybrid channel, according to a respective flow ratio setpoint for each distribution channel.