From ECE to IBM and back: Alumna works on chip for Blue Waters supercomputer

8/26/2010 Susan Kantor, ECE ILLINOIS

Sara Lestage (BSEE '99) knew she wanted to work for IBM when she was in high school. She never thought she would get her dream job and be working on a chip to go into one of the fastest supercomputers in the world. And that supercomputer is being built at Illinois.

Written by Susan Kantor, ECE ILLINOIS

Sara Lestage (BSEE ’99) knew she wanted to work for IBM when she was in high school. To her, it seemed like a company with a good reputation and amazing technological breakthroughs.

IBM test engineer and ECE alumna Sara Lestage (BSEE '99) holds a 300-mm Power 7 processor wafer next to a wafer test tool.
IBM test engineer and ECE alumna Sara Lestage (BSEE '99) holds a 300-mm Power 7 processor wafer next to a wafer test tool.

She never thought she would get her dream job and be working on a chip to go into one of the fastest supercomputers in the world. And that supercomputer is being built for her alma mater, no less.

When the supercomputer Blue Waters comes online in 2011, it will be one of the most powerful supercomputers in the world—and that’s in part thanks to IBM’s multicore POWER7 processor.

Lestage is an IBM test engineer. Her group is responsible for working on server group products, including POWER7, which has eight separate processors that can work together or independently. Lestage works specifically with the DRAM, a type of memory on the POWER7 chip. Putting DRAM on the POWER7 chip was an important innovation for IBM.

“It was a huge step technologically forward compared to our competitors. It’s one of the top server processors in the world right now as far as speed, the DRAM it has, the different modes it can run in for power save, and the different ways the eight cores can work together,” Lestage said.

Lestage has been with IBM since she graduated from ECE ILLINOIS. During her senior year, she went to every job fair she could, paying special attention to the representatives and events from IBM.

“I made as many contacts as I could,” said Lestage, “and I got a few interviews. In November, I got a plant visit to Burlington, Vermont. I came out for a couple of days, did the interview, and I had a nice host who drove me all around Vermont. Even though it was November and it was gray and brown and cold, it was still beautiful, and I thought it would be a really nice place to live.”

Lestage accepted an offer from IBM and began working as a wafer test engineer with server products. It was exactly the thing she wanted to get into. She learned a lot about IBM, including different programming and the manufacturing process. After working as a test engineer for about five years, Lestage switched to working with characterization.

Lestage now analyzes test data. She and her group generate gigabytes of data off the chips when they do wafer and module testing.

“It’s almost too much to look at, so we have to come up with ways to pick out the right data, pick out the most important data, and decipher it into a way that’s man readable,” said Lestage. “It’s kind of like looking at the matrix when you’re first looking at the data.”

They then use the deciphered data to create direction for the test engineers. 

“We bring in all the data, and we decide what message it’s telling us about the technology,” she said. “We use that to improve things across the board for test time reduction, for performance, for quality—just basically everything we need to get the parts out the door.”

Although Lestage works on a small part of a chip that will be used in Blue Waters, she was very excited to find out that she would be working on a project that was so important to Illinois.

”I was really happy to see that my school, my alma mater was working with the company that I work for, with the chip that I work on,” she said. “It was just really neat that it all came together at once. I was pretty proud, and I called up my family about it and everything about it. I’m really proud and happy that this all came together.”


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This story was published August 26, 2010.