Fraunhofer Institute for Applied Optics and Precision Engineering IOF
Fraunhofer Institute for Applied Optics and Precision Engineering IOF

Ion projection lithography assemblies

Metrology benches with integrated electrostatic wafer chuck which are used in ion beam illumination systems in high vacuums are developed at Fraunhofer IOF. The bench assembly comprises a metrology unit with attached interferometry mirrors, an electrostatic wafer chuck with 5 N/cm2 and an integrated, mobile chuck for wafer handling.

 

Requirements

  • Positioning accuracy < 30 nm
  • Time per exposure: 0.2 s (including positioning)

 

Mechanical modeling (FEM)

  • Structural analysis with the objective:
  • Deformation of the metrology unit < 40 nm below own weight
  • Natural frequency > 200 Hz
  • Investigation of thermo-mechanical properties
  • Design of kinematic suspension

 

Design of a lightweight structure

  • Use of special materials:
  • Ceramic SiSiC
  • ZERODUR®
  • Technological development for:
  • Manufacture
  • Assembly
  • Joining technology (bonding)
  • Tolerances of the interferometer mirror set-up
  • Orthogonal ± 2“
  • Pyramidal ± 30“