motion stage High-precision has the right stu

In-house designed and built motion control components are used to fabricate a new high-precision motion stage.

Edited by Miles Budimir

The Proton Motion Stage from Prodrive Technologies is built entirely from in-house off-the-shelf components, ensuring maximal integration and compatibility.

In many specialized manufacturing operations, precision is non-negotiable. Yet, at the same time, many system designers and integrators are also being challenged to increase performance and reduce costs.

To meet the dual demands to increase performance and lower costs, Prodrive Technologies has developed a portfolio of high-precision motion components that are othe-shelf. This new line of products is specifically designed with advanced technologies to help meet the demands of high-performance motion applications. It’s also designed to keep costs under control and make it possible to easily select and combine the right products for the specific application’s requirements.

As an example, the company recently developed a high-precision stage known as the Proton Motion Stage. The stage combines a range of o -the-shelf components, designed and manufactured in-house, to meet the requirements of high-precision and reliable measurement inspection applications, such as those involving scanning electron microscopes or wafer inspection.

One thing that makes the new stage stand out compared to other motion stages is the modular and scalable approach to the design, which also simplifies the process of bringing solutions to market. “In the past, businesses would create a motion stage by sourcing the di erent elements from various suppliers and attempting to combine them for their requirements,” explains Milan van den Muyzenberg, Technical Director for Prodrive Technologies Motion & Mechatronics program. “Our solution has been designed to provide a ‘one-stop shop’ instead, helping to speed up the time to market.”

Because all of the components are manufactured by one source, they are designed to be easily integrated and work seamlessly together. For example, every drive is optimally designed to work with the actuators and every part of the stage can communicate accurately with the master controller. What’s more, these components can also be e ectively combined with products from other manufacturers, if and where required.

Tried and true building blocks

Each application has di erent system requirements, from velocity, stroke, and accuracy, to throughput. A fully configurable system, where one can develop a motion solution by picking and choosing the specific products required, has clear benefi ts.

The Proton Motion Stage is scaled to specific requirements using othe-shelf components as its building blocks. It can even provide a highaccuracy option for those specifying systems for vacuum compatibility, where in the past there has been far less choice compared to stages suitable for atmospheric operation. With conventional motion stages that apply cross roller bearings and appropriate pre-loading, interference can be an issue as a result of temperature changes which can cause variations and negative e ects on friction. The new stage is uniquely built with statically determined preloaded mechanisms to ensure that interference has a limited e ect on motion performance. A number of othe-shelf components were used in its construction, including linear actuators, servo drives, motion controllers and more, including a motion software platform with real-time performance and tooling. Below is a look at how each of these components contributes to the overall design of the motion stage.

The Gryphon family of ironless motors are suitable for applications requiring long stroke motion and a high peak force without force ripple and attraction forces in vacuum conditions. The motors also use flat wire technology to maximize the heat transfer from the coil to the housing.

Highly efficient motion without contamination

A bad actuator in a motion stage has the potential to result in bad yield, poor accuracy, low performance, and reduced throughput. In vacuum stages, it’s also critical that particles from the actuator do not ‘leak’ or cause out-gassing into the environment. In other words, clean operation is vital. Another challenge is that there is no air to dissipate heat within the vacuum environment, meaning that heat must therefore be transferred di erently.

The company’s Gryphon linear actuator series features ironless linear motors that were designed to manage thermal challenges by transferring heat via the metal part of the coil unit. This increases reliability, preventing system failures. In precision applications, such as semiconductor inspection, failure of a part such as a linear motor can have a big impact on operations.

“If a motor phase were to stop working, the whole stage could potentially need to be disassembled and reassembled by a skilled worker, taking valuable time,” says Bart Gysen, Motors Product Line Manager for Prodrive Technologies. That’s why the company has invested in the design and testing of the Gryphon linear actuators specifically to reduce the chances of these sorts of issues arising on site.

Vibration isolation for high positioning accuracy

The company’s Iris actuator is another vacuum-compatible component available o -the-shelf. Six of these limited stroke voice coil actuators are included in the Proton Motion Stage, providing active vibration isolation. This eliminates the disturbances that could disrupt high positioning accuracy. These could include external disturbances and the forces created by the components of the motion stage itself.

With an understanding of each of the components that comprise the motion stage, the company has been able to accurately identify the forces caused by other parts of the machine and reduce the amount of vibrations accordingly, which is also easily adjustable via the control software.

What’s more, the design of the stage takes into account the potential disturbances that the machine could also cause to its own environment and has been designed to eliminate these vibrations as much as possible.

Drives that reduce drift

Drives drift over time. So, when a setpoint is being requested, it will eventually deviate, taking longer to correct, and negatively a ecting performance. In a metrology application, this can be problematic, as accuracy, repeatability, and speed are all needed when moving between positions.

The new stage is designed with drives such as the company’s Apogee and Kepler series drives. These feature low drift components and specially designed voltage reference and custom current sensors, which compensate for drift issues.

Most drives are built with a focus on automation applications, rather than the high-performance environments found in semiconductor applications. However, because every part of the Proton Motion Stage is