Valve Module Pressure Estimation for Uniform Wafer Clamping
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Solution Overview
Problem
Existing clamping devices for flexible materials like silicon wafers struggle to achieve even clamping, especially for differently curved surfaces, due to limitations in precise pressure control and sensor placement.
Innovation Solution
A valve module with a fluid channel system, including sensors and a valve controller that uses model-based determination of fluid pressure at virtual measuring points, allowing for precise pressure control and even clamping of flexible materials by influencing fluid flow and vacuum/pressure distribution across the clamping surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are placed directly at each suction opening to measure pressure, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent introduces a fluid channel as an intermediary element that transports fluid from the suction opening to a remote sensor location. This allows pressure measurement without placing sensors directly at each suction opening, thereby maintaining measurement precision while reducing device complexity and space requirements. The fluid channel acts as a mediator that preserves the pressure information from the remote location to the sensor.
2Measurement precision
If multiple sensors are distributed across the clamping surface to monitor pressure at each suction opening, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the fluid measurement system by creating separate fluid channels for different suction openings or groups of openings. Each channel can be monitored independently or collectively, allowing selective measurement of pressure distribution without requiring sensors at every single suction opening. This segmentation enables precise pressure monitoring while reducing the total number of sensors needed.
3Device complexity
If sensors are placed remotely from the clamping table to simplify installation, then device complexity is reduced, but measurement precision deteriorates due to distance from measuring point
Solution Approach 1:
The fluid channel serves as a mediator that bridges the gap between the remote sensor location and the clamping table suction openings. By transporting fluid through this intermediary channel, the system maintains accurate pressure measurement even when sensors are located remotely, eliminating the trade-off between installation simplicity and measurement precision.
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
Enables reliable and homogeneous clamping of flexible materials, including curved silicon wafers, by accurately determining and controlling fluid pressure at remote measuring points, ensuring flat contact and preventing air cushion formation.
Implementation Method 1
a vacuum between the clamping surface and the underside of the silicon wafer is established which allows to fix the silicon wafer on the clamping surface
Implementation Method 2
a sensor is assigned to the fluid channel, which sensor determines a flow rate value in the respective fluid channel
Data Source
AI summary
A valve module, including a valve controller, at least one valve and at least one fluid channel, in which a first end region of the fluid channel is equipped with a fluid coupling and in which a second end region of the fluid channel is connected to the valve. The valve influences a fluid flow in the fluid channel, in which a sensor is assigned to the fluid channel, which sensor determines a flow rate value in the fluid channel and which sensor is electrically connected to the valve controller, in which the valve controller performs a model-based determination of a fluid pressure using the flow rate value for a measuring point located outside the valve module.