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PHOTOLITHOGRAPHY (OPTION A)

Module Abstract

This module presents an introduction and demonstration of photolithography, the process of copying a high-resolution pattern onto multiple substrates. Students replicate key steps in the process of photolithography, and learn how these processes fit into the fabrication of micro- and nanoscale devices such as integrated circuits. This activity uses solvents and chemicals similar to those used in the electronic industry to perform a key step in the process of manufacturing real integrated circuits.  A modified version of this activity that uses water-based chemistry is also available.

Module Resources and Documents

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Photolithography Slides

Photolithography Module (Option A)

Nano Concepts (Which nanotechnology areas are being explored)

  • Lithography is a method of fabricating devices at the nanoscale

Traditional Science Concepts (Which science areas are being explored)

  • Interaction of light with matter

List of Required Materials (Per person/team)
The full list of items needed for this module is below.  Note that materials for DIY modules are not available through Nano-Link or the Nano-Infusion program.

  • Light duty plastic gloves 
  • Clean compressed air (e.g., Dust-off particle-free compressed air in a can)  
  • Lint-free laboratory wipes 
  • Disposable plastic droppers 
  • Distilled or filtered tap water 
  • Solvents: acetone, isopropanol (rubbing alcohol with 70% isopropanol can also be used) 
  • Photoresist chemical, 100 ml (enough to coat 30 wafers). Safety Data Sheet provided. 
  • Developer chemical, 100 ml of concentrate. This must be diluted 5:1 with distilled water to make 600 ml of developer (enough to develop 30 wafers). Safety Data Sheet provided. 
  • 10 polished silicon wafers (can be cleaned and re-used many times) 
  • Transparent photomask with pattern to be transferred  
  • Spin coater 
  • Clear plastic containment box 
  • Safety goggles 
  • Tweezers 
  • Stopwatch or digital timer 
  • One or two hotplates, preferably with temperature readouts 
  • Four shallow trays to hold liquids (developer solution, rinse water, acetone, isopropanol). Plastic sandwich storage boxes are good because they have tight fitting lids.  
  • One or two desk lamps with a 25W compact fluorescent bulb (do not use an incandescent or LED bulb) 
  • Optional: an optical microscope capable of using reflected (not transmitted) light