"Noise-free" labs

Overview

The Binnig and Rohrer Nanotechnology Center is a state-of-the-art exploratory cleanroom fabrication facility combined with "noise-free" labs shielded against external and internal vibrations, acoustic noise, electromagnetic fields and temperature fluctuations. Each of the six "noise-free" labs has roughly 250 ft2 of floor space, allowing the operation of highly sensitive measurement equipment and tools.

The specifications targeted for these cutting-edge facilities are:

  • Mechanical vibrations: Velocity less than 500 nm/s (x,y,z), below 16 Hz and less than 100 nm/s above the 16 Hz band
  • Acoustic noise: Sound pressure level in a 1/3-octave RMS bandwidth spectrum not more than 50 dBC between the 31.5 Hz and the 100-Hz band and less than 55 dBC above the 100-Hz band
  • Electromagnetic fields (EMF):
    • Flux density less than B = 5 nT RMS in an integral spectrum between 0 and 625 Hz
    • Noise power:
      < 10-12 V2 RMS up to 1 kHz without 50 Hz
      < 10-10 V2 RMS up to 1 kHz for 50 Hz and harmonics
      < 10-10 V2 RMS above 1 kHz
  • Temperature stability: 0.1 °C/1 h and 0.5 °C/24 h

These challenging specifications have been achieved by the following measures:

Mechanical vibrations

  • Separated tool platform vibro-acoustically decoupled from building and operator platform.
    • Massive concrete pedestal (> 65 tons), suppressing frequencies above 25 Hz
    • Tool platform with passive mechanical damping, suppressing frequencies above 3 Hz
    • Active mechanical damping down to 0.5 Hz
  • Operator platform decoupled from tool platform.

Electro-magnetic fields (EMF)

  • Passive mu-metal shielding of each lab to screen external EMF and to reduce EMF within the lab to B < 20 nT
  • Active EMF cancellation system consisting of 3 pairs of Helmholtz coils to cancel the remaining EMF and to guarantee B < 5 nT.

Temperature stability

Distributed, homogeneous-flow air-conditioning system.

Chamber concept

All additional sources of noise, such as pumps, transformers, and power supplies, are placed remotely in chambers adjacent to each lab.