This project was done as independent research during Spring 2012-2013 under the supervision of Dr. Kirkpatrick. The idea of this project was to grow a device, a single carbon nanotube, that can act as a traveling wave tube amplifier. My job was to improve the MEMS design using the integrated circuit design tool LASI7, and then perform photolithography to make an array of the device on a wafer.A Brief Description of the Photolithography Process
Several trials were made throughout the manufacturing process of the device. The fabrication method that gave the best results is described as follows:
Deposit 800nm of titanium and 10nm of silicon dioxide on a 500μm silicon wafer using a PVD 75 machine. Next, submerge the wafer in a dish with a dilute solution of 4 parts iron and 16 parts water for 10 minutes (this is to get a layer of iron nanoparticles for the growth of carbon nanotubes). Then, place the wafer on a hot place at 95 celsius for one minute. After that, spin photoresist on the wafer and expose it with the mask of device array, then bake the wafer again. Develop the wafer in a solution of 30mL developer with 90mL of distilled water to remove the excess photoresist, then rinse with distilled water and spin to air dry. Etch the unused titanium in a standard solution of hydrofluoric acid, peroxide, and water for 5 seconds. Finally, rinse and spin the wafer again. Pictures of the process are shown below.
Spinner machine used to spin the photoresist on the wafer.
Baker used to bake the wafer to ensure the deposition of the particles.
The patterning machine used to expose the mask onto the wafer.
The iron nanoparticle solution.
Wafer submerged in the solution of iron.
Resulting device on wafer.