Vacuum Chamber:

1
Introduction

This project is a combined effort
between The University of North Carolina at
Charlotte (UNC-Charlotte), Massachusetts
Institute of Technology (MIT) and The National
Institute of Standards and Technology (NIST) and
has been funded by The National Science
Foundation for three years (award DMI-0210543).
Conceptual Design of X-Y stage
Fine Motion Stage

• 2nd Generation stage
• 6 degrees of freedom (DOF) error compensation
• 6 Piezoelectric actuator arrangement (2-2-2)
• Complex geometric aluminum shell
• Two-part mixture passive damping
• Currently under construction

• Rigid metrology frame
• Optical prism configuration for laser feedback
• Stacked X-Y motion stage
• Zerodur flats for sliding polymer bearings
• Rohlix/Feedsrew nut driven by frameless motor

Motivation

The primary motivation for this
project is to help facilitate the transition from
nanoscience to productive nanotechnology. The
current system will provide the ability to pick
and place at nanometer levels and compare system
performance with other comparable designs at
international locations such as, National
Physical Laboratory (NPL) in the UK, Technical
University of Eindhoven (TUE) in the Netherlands
and Physikalisch-Technische Bundesanstalt (PTB)
in Germany.

• Objectives
• Development of integrated position measurement
  system with nanometer uncertainties traceable to
  national standards.
• Translation mechanism for multi degree-of-freedom
  motion control.
• Integration of fine motion controllers into
  long-range instrumentation for nano-scale
  manipulation in centimeter-sized workspaces.
• Integration of combined uncertainty analyses for
  determination of system error budget.
• Integration of cascaded multi degree-of-freedom
  control systems.

Seugling, R.M., 2003, Error Compensation Design
For Atomic Scale Metrology PhD. dissertation.
Polymer Bearing Assessment For Slide-ways
Single Axis Slide-way to assess X and Y motion
stage

• Horizontal slide-way
• Vertical slide-way
• Turn table disc mount
• UHMWPE thin film covering brass/aluminum sphere
• Flexure pin
• Cap gage

Critical Requirements Vacuum Compatibility
Range -10-3 to 10-4 Torr - 50 mm
? 50 mm ? 10 mm Velocity Resolution

-5 mm/sec max velocity - 25
nm positioning - 10 nm accuracy

• Key Components
• Mechanical systems (UNCC)
• Vacuum chamber
• Precision translation stage
• Fine Motion stage (RMS)
• Coarse Motion stage
• Optical system (UNCC/NIST)
• Laser interferometer
• Lawall, J., Pedulla, J. M. and Coq, Y.L., 2001
  Ultrastable laser array at 633 nm for real-time
  dimensional metrology, Rev. Sci. Instrum., 72
  (7), pg. 2879-2888.
• Lawall, J. and Kessler, E., 2000, Michelson
  interferometry with 10 pm accuracy, Rev. Sci.
  Instrum., 71 (7), pg. 2669-2676.
• Control system (UNCC/MIT)
• DSP based cascading multi-degree-of freedom
  (MDOF) controller

Adjustable polymer bearing

• Five adjustable bearings for alignment of linear
  slide-way
• Two zerodur optical flats to provide smooth
  repeatable sliding
• Normal and side preload mechanisms to stabilize
  slide-way
• Drive mechanism consist of Rohlix or feed-screw
  nut driven by frameless motor

Thin UHMWPE film over 3/16 diameter sphere
Results
System Control Architecture

• DSP-based control system
• Data ? Analog conversion locally at sensors and
  actuators
• Large motion in 2 axes by feed-screw
• Fine motion by 6-axis piezoelectric stage
• 6-axis interferometric measurement of end point
  position
• Controller integration of course-fine motion
  algorithms

Vacuum Chamber

• 304 stainless steel
• ID 44 inches
• Height gt 24 inches
• Two stage isolation
• external isolation
• internal isolation
• Multiple access ports
• Maglev turbo pump with roughing pump

Block Diagram of System Control Architecture