Cleanroom

Open to all researchers at the university and accessible for external organisations as well, our cleanroom enables wafer-scale micro and nano fabrication. It comprises several class-1000-rated rooms and houses process tools for lithography, dry etch, deposition, chemical processing, post processing and characterisation. These tools are used for rapid prototyping of a range of devices, including photonic structures, microfluidics, micro-lenses, integrated circuits and MEMS. Equipment and specifications listed below.

Linear grating
Microlens profilometry

Lithography

  • High performance electron beam lithography tool
  • Greater than 1cm²/hr writing speed (at 50 % pattern density)
  • 8nm linewidth in HSQ resist
  • 30nm pitch grating with 10nm linewidth
  • Stitching accuracy <20nm
  • Fixed Beam Moving Stage (FBMS) and Modulated Beam Moving Stage (MBMS) patterning modes available (stitching-error-free)
  • Linear grating coupler fabricated on SOI wafer
  • 3" maximum wafer size
  • UV 400 optics
  • Standard processes available using S1800 series, LOR, AZ resists
  • Sub-micron resolution achievable in vacuum contact mode
  • Up to 6" wafer size
  • Sub-micron resolution in vacuum contact mode
  • Backside alignment using through-wafer IR illumination
  • Beam uniformity of 3% across 4" wafer
  • 30 kV accelerating voltage
  • Raith ELPHY plus patterning system
  • 50nm linewidth resolution
  • Imaging with tilt and rotation

Dry etch

  • JLS Designs Plasmapod Plus and Plasmatherm RIE 550-570
  • Available for etching SiO2 and Si3N4
  • Primarily these system are used to produce hard masks for further wet and dry etching steps
  • Other materials have also been etched in the Plasmatherm system, most recently polyimide
  • Gases available are CF4, CHF3, Ar, O2
  • JLS Designs Plasmapod RIE
  • Used for etching silicon and superconducting thin films such as niobium nitride
  • Available gases are SF6, CHF3, Ar and O2
  • A further two gas lines are currently spare
 
  • Configured for III-V, II-VI etching
  • 4" wafer holder
  • Up to 8 process gases available that are suitable for etching a wide range of materials, including silicon and LiNbO3
  • Standard processes available for high quality InP etching
  • Configured for high quality Si etching
  • SF6-based etch processes
  • Etch recipes for
    • RIE, ICP-RIE
    • Bosch
    • Cryo
  • 4" wafer holder, can be configured for up to 8"
  • Laser end-point detection
  • O2 and Ar plasma asher
  • Surface functionalisation and sample cleaning
  • 105mm diameter chamber

Deposition

  • Three targets, 2" diameter - Au, NiCr, Ti, Pd, Pt available and other materials by request
  • Rotational sample holder
  • Confocal or parallel sputter head orientation
  • Better than +/- 5% uniformity across 4" wafer (confocal deposition)
  • Metal deposition - Au, Ni, Ag, Al, Cr, other metals by request
  • Thin films, usually < 300 nm
  • Base pressure typically 1.10-6 mbar
  • a-Si, SiO2 and Si3N4 deposition
  • Loadlocked system
  • Ammonia-free Si3N4 recipes available

  • Metal deposition: Au, Ti, Al, others by request
  • Dielectric material deposition: Al2O3, SiO2
  • Six-pocket e-beam gun with 7 cc volume
  • Integrated into sputter coater system

Chemical processing

  • Acid/base processing
  • HF processing
  • Solvent cleaning
  • Spin station (photoresists)
  • Spin station (coating system for SU-8 and spin coater for EBL resists)
  • Transene TFA Au etch
  • Transene TFG Ni etch
  • Transene TFN NiCr etch
  • Aqua regia
  • Piranha
  • HF/BOE

Post processing

  • Eutectic die bonder
  • Precision placement
  • Vacuum pick and place
  • 4" wafer compatible
  • Variety of cutting modes
    • Single and multi pass
    • Programmable rotation with 0.005° resolution
    • Square, circular, hexagonal substrates, up to 8 mm thick
  • Servo-driven y-axis with 2 μm resolution
  • Feed-rate from 0.1 mm/sec upwards
  • Spindle speed from 3000-40000 rpm
  • Precision diamond scribing
  • Optical alignment
  • 3" wafer vacuum chuck
  • Gold ball bonding
  • 25um diameter wire
  • Fine pitch capillaries available
  • Gold ball and wedge bonding (25um diameter as standard)
  • Aluminium wedge bonding (33um diameter as standard)
  • 17-50um diameter wire bonding possible
  • Fine pitch capillaries available
  • Loop control
  • Manual, semiautomatic, automatic bonding

Characterisation

  • SEM used for surface characterisation and imaging
  • 5-30kV accelerating voltage
  • Primarily a patterning tool, but available for some imaging purposes
  • Variable pressure mode available
  • High precision, scientific-grade microscope, providing atomic-scale resolution
  • Applications in material science, polymers and general surface characterisation
  • Contact and Intermittent contact AFM modes available
  • Stylus with 2 μm diameter tip
  • 3D profilometer
  • Step height repeatability of 4 Å possible
  • Vertical size limit of 1 mm
  • 6" wafer compatible
  • High quality measurement of thin film and bulk characteristics including
    • Optical dispersion (complex refractive index, dielectric permittivity)
    • Film thickness
    • Multi-layer characterisation
  • Films may be isotropic or anisotropic, homogenous or graded
  • Wide wavelength range: 210-2500 nm
  • Variable angle: 45-90 degrees
  • Interferomtric white light profilometer
  • Measures surface profiles with vertical feature resolution down to 0.001 µm by using white light interferometry (WLI)
  • Automated XY stage
  • Two objective lenses
    • 20x : field of view = 1.0 x 0.85 mm (spatial sampling = 0.44 um)
    • 100x : field of view = 0.2 x 0.17 mm (spatial sampling = 0.088 um)
  • Quick and easy thin film thickness measurement
  • Wafers up to 6"
  • Variety of inspection microscopes available
  • Polyvar Polymet microscope fitted with objectives ranging from x2.5 to x150 calibrated to permit length measurements
  • Leica viewers and inspection microscopes also available