A Day in the Cleanroom

When you walk by Engineering Science Building, you can always see people in the cleanroom wearing bunnysuits doing magical things. But it has been somewhat mysterious as of what people actually do in there. In this blog, I’ll show you what I have done so far in the cleanroom as an intern.

Storage Bay

After you get gowned and enter the cleanroom, you would first collect your tools and glassware from this bay. Each group has their own assigned area for storing boxes.

Solvent Bench

It is necessary to clean your wafer before you start to process it and the cleaning is done at the solvent bench. At each bench, there is a laminar flow fume hood to prevent exposure to the fumes and vapors from solvents. There are also nitrogen guns for drying purposes. One typical solvent people use to clean the wafer is Acetone.

(Photo credit: UCSB Nanofab)

Spin Coat Bench

At this bench, people can spin photoresist coating on their wafer. The procedures are to put wafer on the spinner chuck, evacuate the spinner to fix the wafer on the chuck, drip photoresist, set the spinning speed and time (there are built-in recipes to choose from), start spinning, vent the spinner once it stops, and take the wafer off. There are hotplates set at different temperatures (105°C, 110°C, 115°C, etc.) to bake the photoresist coating.

(Photo credit: UCSB Nanofab)

Atomic Layer Deposition (ALD)

This equipment is a plasma-enhanced system for precise layer growth. One of the chambers is used for metal growth, and the other is used for dielectric growth. You only need to load your wafer into the load lock chamber and you can operate the equipment via the computer. There are also well-written process recipes for ALD, and you only need to change the number of cycles to run the recipe depending on the film thickness you want.


(Photo Credit: UCSB Nanofab)

Working in the cleanroom is both exciting and challenging. A lot of things could go wrong through the fabrication process, but you can always learn new skills and new perspectives of thinking.

An Electrical Engineering Internship Experience

Getting the Internship

As a college student, the first thing you probably want to do is to find an internship. That is exactly what I am thinking all the time. It is not easy to get an internship especially in industry. Many internships require you to have prior experiences while no one can have experiences if no one can get one. Well fortunately, here at UCSB, we have fantastic program for all students who want to have such experience. I get an internship in Professor Rodwell’s group this summer. You will know Professor Rodwell, if you are an electrical engineering student like me. When he sent out an email looking for interns, I replied instantly. After a few talks with my mentors, I got the internship.

After I started working, my mentors talked with me about application emails. My mentor said that he received about 50 or 60 emails. Many of those did not even state the applicant’s name and only wrote that “Hi, I’m interested in your intern.” Of course, you would not want interns who just said those two sentences. In the application or the email, the basic information about yourself must be included as well as your interests in the program and some background. The first impression is always important.

Working in UCSB NanoFab, the Cleanroom

The most exciting part of my internship is going to the cleanroom, UCSB NanoFab. The NanoFab is a lab on the first floor of engineering science building. A lot of processes go on inside, like production of nano-devices, chips, and transistors. Entering the lab, the first task is to gown up. Since the object processed in the cleanroom are so small, those gowns are protecting the devices from you not the other way. One of my jobs was to make several ALD deposition onto my wafers. ALD stands for atomic layer deposition which uses gas phase chemical process to deposit materials on different wafers. The ALD deposition machine is one of big machines in the lab. It has three chambers for different deposition of different materials. The procedures on the machine are straightforward. First, wafers are extensively cleaned through Acetone, Isopropyl and distilled water. Then they are put into the ALD machine. Different gases are sent though the chamber and layers of materials get deposited on the wafer. Then wafers are taken out carefully. When all wafers are processed, measurements are made to know how much material are put onto wafers. These might seem simple. While I have a lot of samples, I will spend several hours sitting in front of the machine waiting for results. The patience required for researchers is a lot.

My Summer at UCSB

I’ve always had a fascination with technology, mostly driven by my video game consoles and the old family computer. I read up on how all my machines worked, sometimes tempted to take them apart (fortunately, my fear of not being able to put them back together kept me at bay). Having gone to a high school specializing in science and engineering, I was able to hone in on which disciplines I found the most interesting, specifically devices and nanofabrication, thanks to a nanotechnology course I took my junior year. That was inspiration enough for me to find research quickly upon reaching university. When I came across the opportunity to explore an entirely new coast and meet students from all over the country, I jumped on it (Thanks, internet)!

The nearly six-hour flight to California was the longest I’d ever taken, made all the more disorienting by the three-hour time difference between Santa Barbara and Miami. The first thing I noticed was how little I had prepared for the cool weather (Honestly, I was more concerned about earthquakes and forest fires). Under the impression that Santa Barbara was farther south, and that it must be just as warm as home, I’d packed more shorts than anything else. So after finding a sweatshirt, I had to deal with my next challenge—actual research. Specifically, working within the ECE department through the AIM Photonics program.

I’ve gotten the rare opportunity to familiarize myself with various tools and machines in UCSB’s nanofabrication facility, better known as the cleanroom. Yanking on a bunny suit for the first time was daunting—and a bit harder than the employees made it look. Walking in, hearing nothing but the low hum of machines and seeing white-clad researchers move quickly and quietly carrying wafers of silicon made me uneasy. As intimidating as the machinery looked be in size, with intricate arrays of switches, monitors, and dials, they seemed delicate enough to break with a single touch. And in some ways, they are. Using the equipment in the cleanroom efficiently requires a solid foundation in device physics as well as chemistry. Having only completed my first year in university, most of what I know about the phenomena that allow for nanoscale fabrication comes from high school and self-study. It’s been four weeks since I’ve begun, and already I’ve assigned myself reading—finding whatever articles and textbooks I can to understand why each step in a process must be followed to the tiniest detail. Doing my own homework has really helped make up for the skill gap and has allowed me to make educated decisions in processing (with help). And though training is mandatory in the cleanroom, I am glad to have skilled mentors who can explain the mechanics of each processing step with more clarity than high-level texts. Their advice and support is much appreciated, and this sneak-peek into the lives of graduate students is already helping to shape my future goals in research and academia.