Nanoscale Device Fabrication
The Nanofab Laboratory was established by sponsored research projects from the Ohio Third Frontier program, the Department of Defense and industry partners. The main focus of this laboratory is photonic device fabrication and optical thin film development. The principal investigator is Dr. Andrew Sarangan.
Central innovation: Concept to market.
Contains three magnetron cathodes, with RF and DC excitation. The process gases are argon, oxygen and nitrogen.
Uses a 10kV DC source (max 6kW) four rotatable pockets, substrate heating (up to 600C), substrate cooling (down to 100K) and ion-assisted deposition (IAD).
Used for the deposition of silicon dioxide and silicon nitride. The process gases are silane (SiH4), ammonia (NH3), nitrogen (N2), nitrous oxide (N2O) and sulfur hexafluoride (SF6).
Two RF sources are used to excite the plasma, providing independent control of plasma density and substrate bias. This deep etching system is configured with fluorine-containing gases (SF6, CF4, CHF3) for etching silicon and silicon-compounds, and hydrogen-containing gases (CH4, H2) for etching III-V compound semiconductors.
Substrate cleaning and priming
Used for vapor priming of silicon wafers with hexamethyldisilazane (HMDS) for improving their survivability during wet processing. This can also be used for ammonia image reversal of positive photoresists.
Substrate and photomasks are cleaned by removing submicron particulates while preventing cavitation induced damage.
Used for activating surfaces prior to bonding, for adhesion enhancement and for general surface cleaning. This is a parallel plate low-frequency oxygen and argon plasma chamber.
The work horse for photoresist application, by spin coating.
Optimum development and repeatability of fine features is best achieved with a spray/puddle developer. It can be programmed for develop, agitation, rinse and spin-dry cycles.
A custom-built interference lithography with a 266nm diode-pumped UV laser that can expose 3-inch size wafers. A chemically-amplified deep-UV photoresist is used, to achieve minimum feature sizes as small as 100nm.
A split tube furnace is used for doping semiconductors by thermal diffusion as well as annealing.
Ramps up and down at 150°C/sec with a maximum substrate temperature of 1200°C. Oxygen, nitrogen or argon environments can be maintained in the chamber during the anneal process.
6” diameter wafers can be floated on nitrogen or held by vacuum contact during baking. Temperature can be ramped up or down at programmed levels.
Used for hard baking photoresists after lithography and for curing epoxies.
Capable of creating anodic, eutectic and other thermo-compression bonds between wafers while in vacuum. It has also been retrofitted UV nanoimprinting process.
25μm diameter gold wires are used to make thermosonic bonds from a device to a chip carrier to create a fully packaged device assembly.
Takes line scans of thin films to measure their thicknesses down to about 20 Angstroms of accuracy. Film stress can also be measured by taking pre- and post-deposition scans.
Measures optical transmittance and reflectance to determine the optical constants of thin films. The scan wavelength range is 400nm to 1000nm.
Used for measuring liquid contact angles on substrates.