Pneumatic Pin Lifter Control for Synchronized Wafer Handling
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Solution Overview
Problem
Pneumatic pin lifting devices used in vacuum applications suffer from technological discrepancies leading to non-identical responses during simultaneous operation, causing position and speed deviations, which can result in misalignment and breakage of substrates like semiconductor wafers.
Innovation Solution
An open-loop adjusting stage measures the motion profile of each pin lifting device and adjusts the controlling input to match a reference motion profile, synchronizing the movement of all devices by determining and correcting deviations in timing and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple pin lifting devices operate simultaneously with identical control signals, then productivity is improved through parallel operation, but technological discrepancies cause non-identical responses leading to position and speed deviations
Solution Approach 1:
The system performs preliminary measurement of motion characteristics for each pin lifting device before actual operation. The controller stores individual motion profiles and uses these pre-acquired data to predict and compensate for deviations during simultaneous operation, ensuring synchronized movement without requiring real-time feedback adjustment
Solution Approach 2:
The controller adjusts control parameters (such as pressure timing, flow rates, or actuation sequences) for each pin lifting device based on their measured motion characteristics. By individualizing these parameters according to each device's specific response behavior, the system achieves synchronized operation despite inherent technological discrepancies between devices
2Productivity
If pin lifting devices move substrate quickly to reduce processing time, then productivity is improved, but substrate may break due to adhesive forces or impact stress
Solution Approach 1:
The lifting process is divided into multiple sequential phases with different acceleration levels. The controller applies periodic control signals that first establish gentle contact, then gradually increase lifting speed through staged acceleration phases, and finally execute rapid movement only after the substrate is securely supported by multiple pins, thus preventing breakage while maintaining high overall processing speed
Solution Approach 2:
The system implements a preliminary gentle contact phase where pins approach the substrate at reduced speed and establish contact before full lifting force is applied. This cushioning approach allows adhesive forces to be overcome gradually and ensures even force distribution across the substrate surface, preventing impact-related breakage while maintaining efficient overall processing time
3Device complexity
If pin lifting devices use hard motion stops to limit movement range, then device complexity is reduced, but unwanted shocks occur during substrate handling
Solution Approach 1:
A compliant intermediate element (such as a soft stop or damping mechanism) is introduced between the hard motion stop and the moving components of the pin lifting device. This intermediary absorbs impact energy and reduces shocks during substrate handling, while the overall motion control structure remains relatively simple and does not require complex active control systems
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 approach reduces undesirable effects of intra-pin-lifter technological differences, ensuring reliable and synchronous operation positioning, thereby preventing substrate misalignment and breakage.
Implementation Method 1
a first pneumatic actuator with a first pneumatic cylinder and a first moving member movably arranged inside of the first pneumatic cylinder
Implementation Method 2
a first control valve connected to the first pneumatic actuator and to a first fluid supply and configured to control pressurizing of and/or fluid flow out of or into the first pneumatic actuator
Data Source
AI summary
A pin lifting system includes a first pin lifting device including a first pneumatic actuator with a first cylinder and a first moving member. The system includes a first control valve connected to the first actuator and to a first fluid supply and configured to provide movement of the first moving member, a first fluid sensor, and a controlling unit to control the first control valve based on a measurement signal of the first fluid sensor. The controlling unit is configured to adjust a movement of the first moving member by providing a reference duration of moving a moving member of a pin lifting device from a start to an end position, moving the first moving member, determining a first moving information, comparing the first moving information and the reference moving information and deriving a first moving deviation, and adjusting the first controlling signal based on the first moving deviation.