HP 10721A Two-axis Differential Interferometer

Used in multiple-axis applications, the HP 10721A simultaneously makes two differential measurements -- linear and angular (yaw) displacement. Both measurements reference an external mirror mounted to an object such as a column or inspection tool.

The HP 10721A improves control and overall system accuracy. Configured with appropriate laser head and system electronics, the HP 10721A interferometer can be incorporated into HP's precise positioning systems to improve product quality, increase yields, and facilitate manufacture of precision products.

[ Features ]

High immunity to unwanted interferometer displacement, such as thermal expansion
Column-referencing benefits X-ray systems
Modular, compact design
Monolithic optics for maximized mechanical stability
Abbe offset error decreased with use of small 3 mm beam
Guaranteed interaxis parallelism
Kinematic installation

High Immunity

The HP 10721A measures the linear distance between two objects, instead
of the distance between the interferometer and an object.  Errors common
to the reference and measurement path are removed because both are
equally affected.  This method improves overlay accuracy in many
lithography systems.

Column-Referencing

Because X-rays provide finer linewidth lithography -- the wavelengths
are shorter than optical wavelengths -- slight yaw misalignment can
greatly reduce the system's capability.  The HP 10721A achieves the
required accuracy by referencing the multiaxis stage movement to the
mask holder.

Modular, Compact Design

The design simplifies the integration of the HP 10721A into customized
measurement systems with one to six axes.

Monolithic Optics

Monolithic optics provide tight interaxis coupling and minimize errors
due to vibration.

[ Specifications ]

Weight: 300 g (11 oz)

Axes: Linear and yaw

Available Beam Size: 3mm

Thermal Drift Coefficient (Average): 150 nm (5.9 uin)/degrees C

Angular Range (at 300mm):
	Yaw: +/-0.44 mrad (+/-1.5 arc-min)
	(Angular range is the maximum measurement mirror angle due to all components 
	(i.e., yaw and pitch, or yaw and roll) between the measurement mirror and the 
	interferometer for a 6-axis system. Angular range is dependent on the measurement 
	distance. Angular range is reduced when the reference mirror is misaligned.)

Parallelism (Input to output beams):
	<0.1 mrad (20 arc-sec)

Application: Two-axis Differential Measurements (Plane Mirror)

Optics Resolution Linear: lambda/4 (158.25 nm)

System Resolution:
	Linear:	lambda/1024 (0.6 nm)
	Pitch:	0.05 urad (0.01 arc-sec)

	(When used with the HP 10897B High Resolution Laser Axis Board 
	for VMEbus. Resolution is dependent upon the electronics used.)

Reflector: Custom

Mount Used: Custom

[ Ordering ]

HP 10721A Two-axis Differential Interferometer

The HP 10721A is supported in combination with the HP 10780F fiber-optic
remote receivers.

The HP 10721A can be used in a variety of laser-interferometer
positioning systems including the HP PC-compatible and VMEbus compatible
systems.

[ Assistance ]

To help you make the right instrument choices

Local Sales Office

[ Related ]

Related product families available online:

Differential and Compensation Interferometers

Multiple Axis Interferometers