Gas Flow Node With Characterized Restrictor for Fast Low-Flow Control
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Solution Overview
Problem
Existing mass flow controllers (MFCs) face challenges in achieving accurate and rapid gas delivery for semiconductor fabrication, particularly in terms of space efficiency, cost, and dynamic range of flow rates.
Innovation Solution
The proposed solution involves a gas delivery system with a control apparatus that includes an inlet conduit, a valve, a characterized restrictor, and an outlet conduit, where the ratio of the valve's conductance to the restrictor's conductance is 10:1 or higher. This system operates in conjunction with an upstream pressure regulation and utilizes a remote pressure measurement to control the mass flow of process gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a standard mass flow controller is used, then flow control functionality is provided, but the device occupies excessive space and increases equipment cost
Solution Approach 1:
The patent divides the flow control system into separate functional modules: a remote pressure regulator and a flow node. The pressure regulator handles pressure control remotely, while the flow node handles flow control locally with minimal components. This segmentation allows each module to be optimized independently, reducing overall space requirements while maintaining full flow control capability.
Solution Approach 2:
The patent moves the pressure measurement and regulation function to a remote location upstream of the flow node, effectively utilizing the spatial dimension along the gas delivery path. This allows the flow node itself to be compact since it only needs to contain the flow control elements, not the entire pressure regulation system.
2Speed
If traditional flow control components are used, then flow regulation is achieved, but transition response time is slow
Solution Approach 1:
The patent positions the pressure regulator upstream and remotely before the flow node, so that pressure stabilization occurs in advance before gas enters the flow control section. This preliminary pressure regulation ensures that when the flow node actuates, the gas is already at the correct pressure, enabling faster response without compromising measurement accuracy at the flow node.
Solution Approach 2:
The patent introduces a characterized restrictor as an intermediary element between the valve and the outlet. This restrictor with known flow characteristics acts as a mediator that linearizes the flow control relationship and improves response time by creating a predictable pressure drop, while the flow node still maintains precise control through pressure feedback.
3Adaptability or versatility
If multiple MFCs are used to cover different flow ranges, then wide dynamic range is achieved, but cost and space requirements increase
Solution Approach 1:
The patent designs the flow node with a valve that can operate across a wide range of openings, combined with the characterized restrictor and remote pressure regulation, to achieve wide dynamic range coverage (from very low to high flow rates) with a single device. This universal design eliminates the need for multiple specialized MFCs, reducing both space and cost while maintaining adaptability across different flow requirements.
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
The system achieves improved semiconductor processing efficiency by providing faster transition response times and more accurate flow control, especially at low flow rates, while also reducing space and cost requirements.
Implementation Method 1
A characterized restrictor is placed in series and adjacent with the valve seat to provide a primary flow restriction while having a minimized volume between the valve seat and the characterized restrictor
Implementation Method 2
A valve controlled by an actuator to receive a process gas into a conduit
Implementation Method 3
By knowing the characterization of the restrictor, and accordingly controlling a pressure of the process gas, the desired mass flow is delivered
Data Source
AI summary
In one embodiment, a flow control system for delivering a fluid at a predetermined rate includes a base having a flow path extending from an inlet to an outlet, a proportional valve operably coupled to the base to control fluid flow through the flow path, a flow restrictor located between the proportional valve and the outlet, and a pressure transducer fluidly coupled to a volume of the flow path. The volume is defined between the proportional valve and the flow restrictor.