XY2Z-Theta Motion System

This newly developed platform benefits from all competences that are gained over the more than 50 years of PM's existence. It surely includes extensive knowledge on bearings. In addition, use is made of all expertise on design, motion control, manufacturing and assembly of high-end positioning systems to realize this product.


The XY2Z-Theta motion platform is designed for next generation wafer inspection and metrology applications. However, its modularity and scalability allow customization of this stage to suit other applications. At PM we understand the industry's challenges. We can either modify our existing motion platforms or design entirely new ones, depending on your requirements.

The design of the motion platform is inspired by the results of in-house developed topology optimization software. Hence, the stage is well balanced in terms of mass and stiffness. The integrated design has inherent advantages over conventionally stacked systems: dynamic performance is increased and Abbe errors are reduced.

The first linear gantry axis is built on a granite structure, to provide a solid and accurate base. The second linear axis that moves perpendicularly to the first one is integrated in the gantry axis. This makes sure that the stage adheres to the philosphy in which all bearings, centers of gravity and motors are aligned in a single plane. Reducing the arm of the moving masses increase the observable stiffness and hence system performance benefits.

Lightweight Design

The specifications of the XY stage are a result from a clear design philosophy as well as thorough analyses of the stage structure and smart selection of components.


Acceleration 20 m/s2
Accuracy <1 μm
Jitter <25 nm

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Video of the XY2Z-Theta motion system

Thermal Management

The challenge for dynamically moving systems is to keep the stage center at the location where it is expected despite the significant amount of heat that is put into the moving parts. Thermal stability of the system is guaranteed by a number of innovative solutions. Special alloy materials are used to reduce movement of the wafer center, heat sinks are used to extract heat from the motors and isolating materials are used to prevent heat from being transferred to ctritical components.

2Z-Theta Module

The compact 2Z-Theta module combines two Z-axes and a rotating axis in one compact package. There is a fine-Z axis  with a 5 mm stroke that allows for focus of the wafer. The coarse-Z axis with 15 mm travel allows for wafer loading and unloading. Both Z axes are gravity compensated. Bearings for these axes are PM's RSDE type such as shown on the left. Smoothness, precision and stiffness are key characteristics of these bearings. 

The theta axis includes a special designed variant of the precision flat mounted table bearing FMB. These bearings are famous for their low runout and wobble. At the same time they provide high rigidity and smooth running charachteristics.

Special features that are included in this module are three seperate vauum lines at waferchuck level for fast chucking and de-chucking.

2Z-Theta module specifications

Coarse Z-axis
Stroke: 15 mm

Fine Z-axis
Stroke: 5 mm
Jitter: <10 nm (with optional Vibration Isolation System)

Stroke: 360o (continuous)
Speed: 5 rev/s
Acceleration: 30 rev/s
Accuracy: <15 μrad
Jitter: <0.15 μrad

News release - Motion platform design overview

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