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.

Rodwell Interns  Posted by 10 Sep 2019 / 0 comments

Optics: from Rochester to Santa Barbara

After 15 hours and over 2500 miles, I finally landed in Santa Barbara, CA. The first thing I noticed about Santa Barbara was the perfect temperature, the smell of the ocean, and the dark cloudy sky. Later, I learned it was a weather pattern known as June Gloom. Once I arrived at my house, I told my new housemates that I am from Rochester, NY; they looked at me with awe. Transplanting myself from one corner of the country to another corner was not as scary as I thought. Aside from the lack of sidewalks and seasons, I found similarity through the research and the people I work with. Walking through the labs, I noticed the familiar floating optical tables, overhanging microscopes, and a jungle of fiber optics cables. In the student office, I discovered that they also have a joint Optical Society of America (OSA) and SPIE (The International Society for Optics and Photonics) club. This became the place I would call home for the following 2 months.

Once I had settled down, I spent the first week learning more about my research and filling out some very (not) exciting paper work. I ran around the campus trying to get my student ID. Then I began doing more reading on my research and… I got confused. Like all research, confusion is the first sign of learning. I remembered to ask questions, routinely speak with my graduate mentors and continue to ask more questions. However, you should always attempt to seek the answer out first, so the knowledge will stay with you longer. Next, I begin learning how to design a simple PCB board and test the photonic switches that were fabricated in New York State! The wonderful thing about AIM Photonics is that it exists on both coast and there will soon be a facility in downtown Rochester. After spending the second week training on various measurement techniques, I thought I was ready to do the experiments.

I remember standing in front of the optical spectrum analyzer, also called an OSA (not to be confused with the society), wondering why I couldn’t get any signal. After checking every single connect and alignment, I found my answer. I forgot to turn on the laser. Trivial things like that can trip you up, and even the pros are prone to it. On one weekend, I came to lab to do more measurements with one of my graduate mentors. After an hour of alignment, we measured less than 0.1 milliwatt of power at the end of our fiber. We continued to spend more hours debugging the mistakes here and there and finally fixed it. The takeaway of that weekend was to be very mindful when doing measurements. If there is something wrong, check every step/connection on the way. It could be one or multiple things; don’t just assume but hypothesize and test.

Nearing the end of my internship, I feel a bit nostalgic. I didn’t get to go to the beach as often or as I imagined: sipping a margarita under the beautiful California sun. But, I did meet a lot of wonderful people from the AIM Future Leader program and received some great advice from my graduate student mentors. My housemates are also awesome people and overall, I enjoyed the company of the people more than the beach and the weather. However, Rochester could use some more sun.

AIM  Posted by 16 Aug 2018 / 0 comments

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.

Rodwell Interns  Posted by 09 Aug 2018 / 0 comments