A photographic tour of the Hewlett Packard Labs clean room

By Curt Hopkins, Managing Editor, Hewlett Packard Labs
Photography by Rebecca Lewington, Analytics and Advanced Architectures Marketing, Hewlett Packard Labs

Tho Tran is a senior process development engineer at Hewlett Packard Labs. But she calls herself a cook. A baker to be precise. That is primarily because she bakes bread at home. But in the class 10 cleanroom, known informally as "the kitchen," she’s still the chef.

Hewlett Packard Labs has three clean rooms: A multi-station production room shared with HP, Inc., called “the kitchen,” a second, smaller room shared with Labs-spinoff startup Leia, and the “stepper room” where circuit patterns are laid down on silicon wafers, also shared with Leia. Despite the centrality of these rooms to Labs’ mission, not many people really know what happens there. This photo essay seeks to remedy that.

If Tho is the cook, then cleanroom engineer Carl Chow is the maître d'hôtel, and photonics research engineer Thomas Van Vaerenbergh is the valued diner with a standing table. They accompanied technical communicator and photographer Rebecca Lewington and I into the sweltering, roaring forge where the dishes get cooked and assembled.

So put on your weird plastic onesie, strap on your oversize lab booties, don your mask, drag your cowl over your head, and start regretting the decisions you’ve made that brought you here. I mean, enter the clean room.

Class 10 clean rooms allow only 10 particles greater than 0.5micrometers in size per cubic foot of air. For comparison, an average human hair is 50micrometers in diameter. Typical air has 10,000 times more particles than a class 10 cleanroom. Just one particle could render a microchip useless.

In addition to being clean, these rooms are also loud, thanks to the outflow system, and hot, due to the machinery and products needing a 70 degree temperature to be happy, and yellow, so the harsh white light doesn’t alter the final products.

Although optics are what Tho does for Thomas, there are many other projects and products going through, and coming out of, the clean rooms. But we’ll stick with Tho and her “recipes” for a photonic wafer and the chips that result. (The processes and their ingredients really are called recipes by the engineers.)

Tho suits up. These suits are rather the opposite of hazmat suits. They protect the devices, materials, and products from us.
Thomas peers intently at an atomic layer deposition system, which deposits materials on wafers in layers a single atom thick.
Tho works at a control screen devoted to various types of deposition, or coating, processes, including physical vapor deposition, chemical vapor deposition, atomic layer deposition, and electron beam evaporation deposition. Carl looks on.
In the “wet bench” aisle, where Thomas, Carl, and I discuss where Tho could have run off to.
Turns out she’s preparing a wafer for wet processing.
Tho dries off a wafer after wet processing.
Tho places a wafer into the vacuum chamber of an electron-beam deposition system.
Tho opens the ultra-high vacuum chamber.
Safety is paramount. Process and patience are key, along with stations like this one which provides burn gel in case an engineer gets splashed with hydrofluoric acid, something which has thankfully never happened here.
Part of that process is “a place for everything and everything in its place,” including broken wafers.
The second clean room, replete with IP-sensitive Leia wafers.
In the third clean room is where you will find the combined track-and-lithography stepper system.
Tho loads wafers into the track at the stepper’s front end, where the process of depositing and baking on photoresist takes place. To use a photography metaphor, think of it as photographic emulsion.
Tho handles a photomask, a six-inch square of ultra-pure crystal (think of it as the negative). The stepper will shine ultraviolet light through it thousands of times to create the grid of chips on the wafer.
The proof of the pudding is in the tasting: a thumbs-up from the chef.