Over Actuated Test Setup
Internal research
For a lightweight 450mm wafer chuck a setup was designed and built to test smart actuator placement.
In semiconductor industry throughput is increased to reduce the costs per die, e.g. by increasing wafer diameter from 300 to 450 mm. A big disadvantage of larger wafers is larger, and thus, heavier (means slower) wafer stages. The conservative approach of a light and stiff chuck must be replaced by a lighter, but also, flexible chuck. By using an optimized mechanical structure and smart actuator placement several eigenmodes will not be excited.
This set-up shows that by using smart actuator placement bandwidths of 200 Hz at 7 kg stage mass (for 450mm) can be obtained. This shows that the same performance can be obtained for a 450mm stage as with current 300mm stages.
Challenges
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Realization of a light and flexible 450mm wafer stage with no additional sensors and control complexity
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Stage design with predictable mode shapes
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Seperate frame vibrations from stage dynamics
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Mechanical decoupling to apply 3x SISO control on 4 actuators for 3 DOF
Key Competences
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Predictive modeling on mode shapes
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Concepts for dynamic decoupling of frame vibrations
Results
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Rubber membranes in actuator suspension to prevent excitation of base frame (replacement of force frame)
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New actuator design
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Controller implemented on industrial NYCE4000
Cooperation
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Magnetic Innovations for actuator design
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Bosch Rexroth for NYCE controller
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Louwers Glas