Branch Flow Ratio Control Using Hybrid Velocity and Flow Modes
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Solution Overview
Problem
In semiconductor manufacturing, existing flow rate ratio control devices struggle to achieve target flow rate ratios in a timely and consistent manner, requiring longer times to reach desired flow velocities and flow rates, which affects gas uniformity and process efficiency.
Innovation Solution
A flow rate ratio control device with a main flow path and branch flow paths, equipped with fluid control devices featuring valves and pressure-based flow rate sensors, allows for simultaneous control of flow velocity and flow rate, using a target receiving unit, target flow rate calculating unit, and operation setting unit to operate one device in flow velocity control mode and others in flow rate control mode, with optional pressure and flow velocity sensors for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional flow rate ratio control devices are used with only flow rate control, then the system structure is simple, but the time required to achieve target flow velocity is long and cannot be kept constant
Solution Approach 1:
The patent applies parameter changes by transitioning from pure flow rate control to a hybrid control mode that incorporates flow velocity control. The operation setting unit dynamically adjusts control parameters based on whether the system is in a transient state (requiring flow velocity control) or a steady state (requiring flow rate control), thereby optimizing the time to achieve target flow velocity while maintaining control accuracy.
2Speed
If pressure-based flow rate sensors are added to enable flow velocity control, then flow velocity control capability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the control device to perform multiple functions through a single integrated system. The same pressure-based flow rate sensors serve dual purposes: measuring flow rate for traditional ratio control and providing data for flow velocity control. The operation setting unit seamlessly switches between control modes, making the system multi-functional without requiring separate control systems.
3Loss of time
If flow velocity control mode is implemented, then the time to achieve target flow velocity is reduced, but control system complexity increases
Solution Approach 1:
The patent applies dynamics by implementing a dynamic control mode switching mechanism. The operation setting unit continuously monitors system state and automatically transitions between flow velocity control mode (during transient states when rapid response is needed) and flow rate control mode (during steady states when precision is prioritized). This dynamic adaptation optimizes response time while managing control complexity through intelligent mode selection rather than permanent system complexity.
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 enables faster and more consistent achievement of target flow velocities and flow rate ratios, reducing the time required to reach desired states and ensuring uniform gas mixing, thereby improving process efficiency and gas uniformity in semiconductor manufacturing.
Implementation Method 1
a pressure-based flow rate sensor that is disposed on a downstream side of the valve
Data Source
AI summary
A flow rate ratio control device is provided with a main flow path, a plurality of branch flow paths that branch off from a terminus of the main flow path, a plurality of fluid control devices that are provided respectively on each branch flow path, and that are each equipped with a valve and a pressure-based flow rate sensor that is disposed downstream of the valve, and an operation setting unit that establishes settings such that, based on the target flow rate ratio, any one fluid control device from among the plurality of fluid control devices is made to operate in a flow velocity control mode in which the flow velocity of a fluid is controlled upstream of each valve, and the remaining fluid control devices are made to operate in a flow rate control mode in which the flow rate is controlled based on the target flow rates.