Flatter, more accurate wafer positioning from Queensgate
The new WP120B Z-axis, tip-and-tilt piezo positioning stage for 300 mm (12”) wafers offers minimal off-axis errors for consistent focus and measurement accuracy.
Queensgate has launched the latest of its piezo nanopositioning stages, the WP120B low-profile Z-axis, tip-and-tilt stage. It was developed in response to customer demands for improved roll and pitch errors in wafer piezo nanopositioning stages.
The WP120B features parallel kinematic 3-point high-stiffness actuators, flexure guidance, high-bandwidth closed-loop control, and multipoint sub-nanometer-resolution capacitive displacement sensors directly measuring the moving platform. This has enabled a ~15x reduction in off-axis errors, from ~20 μrad to 2 μrad, with no loss of speed over the stage’s full 120 μm Z travel range.
The flatness ensures consistent focus and improved confidence in measurement accuracy across a large surface area, making it ideal for inspecting 300 mm wafers. It is available with an adapter plate for the H112 heavy-duty industrial stage from Prior Scientific for high-precision X- and Y-axis motion with a 300 mm travel range.
The WP120B is suitable for high-throughput applications where Z-axis speed and accuracy are vital: with Queensgate’s digital closed-loop controllers, its step-settle time is as low as 14 ms for a 1 μm step under an 8 kg load. Typical applications include:
- Wafer inspection and defect detection
- Chip verification
- Surface structuring
- Interferometry and metrology