Custom Design Examples for Ferrofluidic^® Vacuum Feedthroughs

Applications: CVD, vacuum deposition systems, gas handling modules

Ferrofluidic rotary gas unions offer manufacturers of CVD and other deposition systems an efficient and flexible method of introducing gases into a process. A static gas feed runs into the rotating shaft which supports the wafer. This ensures that the gas outlet is in the center of the wafer, resulting in uniform coating characteristics.

Applications: wafer handling, CVD wafer rotation with stationery inner shaft

Ferrofluidics offers multi-axial feedthroughs for wafer handling applications. These offer extremely high repeatability with zero backlash. Linear motion can be incorporated and a cantilevered seal design is optional for UHV optimization. Since the feedthroughs employ a single shaft per axis to transmit torque to the load, torsional stiffness is maximized allowing for the highest torque transmission of any UHV wafer handling rotary sealing technology.

Applications: MOCVD, LPCVD, PECVD, designs where aggressive cleaning agents are used

Reactive gas seals for applications such as MOCVD use an inert fluorocarbon based fluid. They feature a cantilevered seal design to protect the bearings from process gases. Special materials are used in the seal construction. Inert gas purges or protective plating can also be added to prevent corrosive attack of seal components.

Applications: anywhere where a motor is used, particularly where servo control is necessary

An in-line motorized feedthrough is compact in comparison to an offset or shaft-coupled drive. Ferrofluidic in-line motorized feedthroughs feature a brushless servomotor and matching amplifier with power supply and sinusoidal commutation. Application appropriate feedback devices and command loops are incorporated. As the feedthrough has the motor fully integrated around the shaft rather than coupled to it, it provides optimum drive-to-load torque efficiency over the life of the product. Direct drive feedthroughs are available with either solid or hollow shafts.

Applications: optical coating applications, 300 mm wafer rotation mechanisms

High speed, large diameter hollow shaft feedthroughs are ideal for optical coating applications, e.g. fiber optic filter manufacturing. These feedthroughs are configured with a double Ferrofluidic seal to enable static access to the rear of the seal. Drive is supplied via a toothed belt through the side of the housing or an integral brushless motor within the feedthrough housing. The product can then be accurately observed or measured through the large diameter hollow shaft without the difficulties associated with a rotating window. Seals with an 8" internal diameter can be used at speeds up to 1000 rpm.

Applications: wafer handling, ion implantation

Ferrofluidic spindles can be engineered to rotate with as little as 0.0001" (0.005 mm) of run-out. These products are ideal for high precision wafer handling/aligning applications and wafer/substrate rotation applications where wobble requirements are very stringent. Axial, radial and torsional spindle stiffness is achieved by custom engineering the bearing and shaft designs.

Applications: FLIR devices, retrofit feedthroughs, rinser-dryers

Ferrofluidics offers extremely compact seals with small seal envelopes. These are sometimes the only option in the case of retrofits where there is limited axial or radial space available. In new designs they are often beneficial to the overall system layout.

Applications: wafer handling and alignment with Z-motion

Rotary linear feedthroughs integrate a Ferrofluidic rotary seal with an edge-welded metal bellows linear seal. They use pre-loaded angular contact rotary bearings and sleeve or ball-type linear bearings. Such feedthroughs are ideal for wafer handling and aligning applications where indexing and translation are involved.

Ferrofluidics offers a range of retrofit feedthroughs for many vacuum systems supplied by leading semiconductor OEMs. Please call for details about the feedthroughs available for your system.