PHOTOLITHOGRAPHY (OPTION A)
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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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
- 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