Nano precision X-Y-Rz stage
Client confidential
In close cooperation with Bosch Rexroth a high accuracy stage for wafer alignment has been developed and built.
The end customer needs this stage for wafer production using an alternative lithographic process. Every cycle the relative position of the wafer w.r.t. mask is measured in three directions (X, Y and Rz). This measurement is done by an external measurement tool, using marks on both wafer and mask. This relative measurement serves as base for generating an accurate alignment set-point. Alignment requirements:
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Stroke of ±2.5 mm in X and Y and ±1.5 deg in Rz
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Settled within 50 nm in 30 ms
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drift <10 nm in 10 seconds
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Noise ±60 nm ±3σ over 10 seconds
Challenges
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Integrated air-bearing design in wafer table
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Actuator / sensor layout w.r.t. CoG
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MIMO control strategy
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Force frame design to reduce disturbance from set point reaction forces
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Elastic sensor decoupling
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Design and realization of an external test setup to qualify performance @ tool-point
Key Competences
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Predictive modeling, Dynamic Error Budgeting
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Construction principles for precision engineering
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Advanced Motion Control
Results
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Complete tested prototype, both functional and on performance
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Test tool for qualification @ tool-point
Cooperation
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Simex Technology for air bearing design
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NTS Mechatronics for cleanroom facilities and assembly support
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Bosch Rexroth (delivery E-components and implementation motion control on NYCE 4000 platform)