PlanarHDX Two Axis, Silicon Carbide, Planar Air-Bearing Stage


Design Features

  • Advanced silicon-carbide structure for high-dynamics and ultra-precise motion performance
  • Speeds to 1.5 m/s and accelerations to 5 g
  • Proprietary reaction-mass design enables fast turnaround and move-and-settle times
  • Active and passive isolation system options
  • Encoder or laser interferometer feedback
  • Linear motors with improved thermal management
  • Advanced control solutions offer enhanced throughput

Aerotech’s long history of supplying ultra-precise positioning systems in high-technology fields such as semiconductor manufacturing has enabled ongoing development and improvement of key motion technologies. By building upon these technologies, Aerotech has developed the PlanarHDX, the most advanced commercially available planar air-bearing platform on the market. Designed using an FEA-optimized silicon carbide structure and optimized air-bearing compensation techniques, the PlanarHDX provides the highest possible dynamic performance while maintaining unparalleled geometric characteristics and positioning accuracy.

Ultra-Precise Design

PlanarHDX structural elements have been designed using an advanced silicon carbide ceramic that has a specific stiffness (elastic modulus/density) five times higher than aluminum and a coefficient of thermal expansion approximately five times lower. The resulting material along with an FEA-optimized structure enables high-throughput motion (1.5 m/s scan speeds and 5 g peak acceleration with a payload up to 20 kg) without sacrificing dynamic tracking, geometric performance, or thermal stability.

Using nearly 50 years of experience in air bearing and precision motion system design, Aerotech has developed a new air-bearing compensation strategy that increases stiffness and load capacity for demanding high-dynamic applications. Using proven air-on-air preloading in critical bearing elements improves turnaround and settling times over vacuum-preloaded designs.

A proprietary reaction-mass design dramatically reduces stage-induced forces in the step-axis that are transferred to the isolation system or customer’s structure (optics, sensors, etc.). By minimizing these dynamic forces, move-and-settle time is reduced and process throughput is increased.

Depending on the application requirements, the PlanarHDX is available with passive or active isolation systems. Additional axes such as Z-tip-tilt or Z-theta designs as well as custom wafer load/unload mechanisms and wafer chucks are available. Machine weldments, complex granite base structures or enclosures can also be provided.

High Accuracy Feedback

As a standard offering, the PlanarHDX is available with low-expansion glass scales on each axis. The scale and readhead locations are chosen to minimize Abbe and thermally-induced errors. For applications requiring the highest-levels of accuracy, Aerotech can provide laser interferometer feedback with mirrors located at the workpoint with integrated wafer chucks or workholding devices. In both encoder and interferometer feedback systems, the materials and mounting methods are optimized to provide high dynamic operation while minimizing thermally-induced accuracy errors.

Noncontact Direct-Drive Technology

At the heart of the PlanarHDX are Aerotech’s BLM and BLMH linear motors, which employ an ironless forcer design for ultra-smooth motion. Both the step and scan axes use multiple motors driving near the center-of-mass to provide exceptional vertical/lateral straightness and minimal angular errors. The motors are thermally-isolated, and for high duty-cycle applications can be water cooled to minimize thermal errors caused by motor heating.

Advanced Mechatronic Solution

Aerotech manufactures not only the mechanical elements, but also the electronics and control elements of the positioning system. In doing so, critical drive and software control features can be tightly coupled to the mechanics, providing not only a one-stop solution, but also enabling a complete mechatronic solution with unmatched performance. Many advanced control features such as directional gain scheduling, iterative learning control, and harmonic cancellation exist as a result of development for use in specific applications with Aerotech controls and mechanics.

Aerotech’s ETM (Enhanced Throughput Module) option helps improve the positioning performance of high-dynamic motion systems like the PlanarHDX by directly measuring the unwanted motion of the machine base and communicating it back to the controller. By working in concert with the Dynamic Controls Toolbox and Aerotech controllers, the ETM significantly improves move-and-settle time and contouring performance, increases throughput of existing and new machines, and greatly reduces the effects of frame motion on the servo system.


Mechanical Specifications

Travel(1) 450 mm x 450 mm 600 mm x 600 mm 750 mm x 750 mm
XY Accuracy(2,3) ±100 nm
Bidirectional Repeatability(3) ±15 nm
Straightness 200 nm per 450 mm
Flatness 300 nm per 450 mm
Pitch/Roll 10 µrad (2 arc sec) per 450 mm
Yaw 5 µrad (1 arc sec) per 450 mm
XY Orthogonality <2 µrad (0.4 arc sec)
Maximum Speed(4) X Axis(Step) 1.0 m/s
Y Axis (Scan) 1.5 m/s
Peak Acceleration(4)
(With Rated Payload)
X Axis (Step) 3 g (29 m/s2)
Y Axis (Scan) 5 g (49 m/s2)
RMS Acceleration(4)
(With Rated Payload)
X Axis (Step) 1.1 g (10.8 m/s2)
Y Axis (Scan) 1.2 g (12.8 m/s2)
Rated Payload
(Maintaining Dynamic Specifications)
20 kg
Maximum Payload(4,5) 40 kg
In-Position Jitter (On Air)(6) ±2.5 nm (Z), ±5 nm (X and Y)
Typical Step and Settle Times (With Rated Payload and Passive Isolation); Measured on a 750 mm x 600 mm System, ±100 nm Settle Window 25 mm step - X-axis: 150 ms; Y-axis: 115 ms
100 mm step - X-axis: 245 ms; Y-axis: 190 ms
300 mm step - X-axis: 450 ms; Y-axis: 380 ms
System Operating Pressure(7) 550 kPa ±35 kPa
Air Consumption(8) 130 SLPM
Material SiC Ceramic, Granite
MTBF >40,000 hrs
  1. Other custom travels available upon request.
  2. XY accuracy measured over 450 mm x 450 mm area. Specified for linear encoder options. Consult factory for laser interferometer feedback.
  3. Results highly dependent on environment and duty cycle. Temperature stability to <0.1°C required.
  4. Requires the selection of an appropriate amplifier with sufficient voltage and current
  5. Maximum load may be limited by specifications required.
  6. In-position jitter reported as pk-pk. Highly dependent on the isolation system and environmental conditions.
  7. To protect the air bearing against low pressure, an in-line pressure switch tied to teh motion controller ESTOP input is recommended.
  8. Air supply must be clean, dry to -15°C dew point and filtered to 0.25 µm or better. Recommend Nitrogen at 99.9% purity.

Electrical Specifications

Drive System Brushless Linear Servomotors
Feedback Glass/Zerodur™ Linear Encoders
(Laser Interferometer Options Available)
Maximum Bus Voltage 340 VDC

Recommended Controller

Multi-Axis A3200 Npaq 6U
Ndrive HLe
Ndrive HPe


  • PlanarHDX
    PlanarHDX Dimension Image

Ordering Information


Option Description
PlanarHDX The PlanarHDX series is a two-axis, ultra-high performance, air-bearing stage manufactured from an advanced silicon-carbide ceramic for high-dynamic and ultra-precision motion performance. Includes ceramic air-bearing stage with granite base and cable management.

Stage and Travel

Option Description
PlanarHDX-450-450 Silicon-carbide, planar air-bearing; PlanarHDX-450-450
PlanarHDX-600-600 Silicon-carbide, planar air-bearing; PlanarHDX-600-600
PlanarHDX-750-750 Silicon-carbide, planar air-bearing; PlanarHDX-750-750

Feedback (Required)

Option Description
-E1 Incremental glass encoder, 1 Vpp output
-E2 High-accuracy incremental glass encoder, 1 Vpp output
-E3 High-accuracy low-expansion incremental glass encoder, 1 Vpp output
-E4 High-accuracy/resolution low-expansion incremental glass encoder, 1 Vpp output
-E5 Laser interferometer feedback

Reaction Mass (Optional)

Option Description
-RM Reaction-mass design, step axis

Motor Cooling (Optional)

Option Description
-WC Water cooling on all linear motors

Isolation System (Optional)

Option Description
-ISO1 Active vibration isolation system
-ISO2 Passive vibration isolation system

Cable Management (Optional)

Option Description
-CMSxxxx Cable management for customer air lines, auxilliary connectors, additional axes, etc. Contact factory for details.

Performance Grade (Required)

Option Description
-PL4 Ultra-high accuracy 2D performance

Integration (Required)

Aerotech offers both standard and custom integration services to help you get your system fully operational as quickly as possible. The following standard integration options are available for this system. Please consult Aerotech if you are unsure what level of integration is required, or if you desire custom integration support with your system.
-TAS Integration - Test as system 
Testing, integration, and documentation of a group of components as a complete system that will be used together (ex: drive, controller, and stage). This includes parameter file generation, system tuning, and documentation of the system configuration.
-TAC Integration - Test as components 
Testing and integration of individual items as discrete components. This is typically used for spare parts, replacement parts, or items that will not be used or shipped together (ex: stage only). These components may or may not be part of a larger system