MicroWriter ML®3

Instrument Specification

Manufacturer: Durham Magneto Optics Ltd

MicroWriter ML®3 is a high-performance, direct-write optical lithography machine. for direct writing applications and low volume mask making.  Easy to use Windows® based software means most exposures can be set up and launched with just a few mouse clicks. Four different resolutions (0.6μm, 1μm, 2μm and 5μm) can be selected automatically via software. Allows non-critical parts of the exposure to be performed rapidly while retaining high resolution writing for critical parts. The MicroWriter ML®3 features an optical surface profilometer tool and an automated wafer inspection tool for examining fabricated structures. 

Key features and specifications

  • 195mm x 195mm maximum writing area. 
  • 230mm x 230mm x 15mm maximum wafer size. 
  • 0.6μm, 1μm, 2μm and 5μm resolutions across full writing area. 
  • Automatic selection of resolution via software – no manual changing of lens required. 
  • 365nm & 405nm long-life semiconductor light source, suitable for broadband, g-, h- and i-line positive and negative photoresists (e.g. S1800, ECI-3000, MiR 701, SU-8). 
  • XY interferometer for precise motion control. 
  • Extremely fast writing speed - up to: 20mm2/minute (0.6μm resolution), 50mm2/minute (1μm resolution), 100mm2/minute (2μm resolution) and 180mm2/minute (5μm resolution). These allow a typical 50mm x 50mm area combining critical and non-critical areas to be exposed in under 30 minutes or a typical 100mm x 100mm area to be exposed at 2μm resolution in under 2 hours. 
  •  Autofocus system using yellow light which automatically tracks surface height variation during exposure, compensating for bowed or inclined substrates and surfaces with highly irregular topography. No minimum wafer size. 
  • High quality infinite conjugate optical microscope camera with x3 aspheric objective lens and x5, x10 and x20 Olympus plan achromatic objective lens and yellow light illumination for alignment to lithographic markers on the wafer (±0.5μm 3σ alignment accuracy). 
  • Automatic changing between microscope magnifications via software – no manual changing of lens required. Additional x4 digital zoom can be selected in software. 
  • Grey scale exposure mode for 3-dimensional patterning (255 grey levels). 
  • Software API for external interfacing and control. 
  • 100nm minimum addressable grid; 20nm sample stage resolution. 
  • Acceptable file formats: CIF, BMP, TIFF and (via Clewin 5) GDSII. 
  • Built-in 2-dimensional optical surface profiler (100nm thickness resolution) for examining exposed resists, deposited layers, etching and other MEMS process steps. 
  • Automatic wafer inspection tool allowing each die on a wafer to be imaged. 
  • Virtual mask aligner mode in which the pattern to be exposed is displayed on top of the real-time microscope image, allowing the machine to be used like a traditional mask aligner. 
  • Includes passive vibration-isolation optical table with integrated monitor and keyboard mount. 
  • Light-excluding enclosure with safety interlock. 
  • Temperature stabilisation to ±0.5⁰C 

Training information

  • About 3 hours of training depending on application.

Basic operation – Youtube


Perlman building –1 floor, room 15 (Yellow room)

Staff Contacts

Training information

2-4 hours of training.
Prerequisites: training materials on WEB. 
Verbal explanation accompanied with SOP manual on MA6 operation principles: 

  • Safety.
  • Turn on/off.
  • User menu.
  • Basic operation.
  • Demonstration of sample loading.
  • Alignment.
  • Exposition parameters settings.
  • Exposure.
  • Trainee’s hands-on under staff member supervision. 

Links & Documents