Chip makers plot shift to larger silicon wafers

Chip makers Intel, Samsung Electronics and Taiwan Semiconductor Manufacturing Co. announced Monday that they will collaborate to move chip manufacturing onto larger silicon wafers by 2012.

The move to 450-millimeter wafers will help semiconductor makers keep pace with demand for chips and also help reduce manufacturing costs per chip, Intel said. It should also result in more efficient use of the resources used to make chips, including water and energy.

The companies said they would work with the rest of the industry to help make sure all of the required components and infrastructure are developed and tested for a pilot manufacturing line by the target date.

The new wafers will be an upgrade from the 300-mm wafers that many big chip makers currently use to manufacture chips. Intel began large-scale use of 300-mm wafers in 2001, Rob Willoner, a technology analyst at Intel, said recently.

Once chip companies have made the move, their manufacturing costs should fall and end-users should start to see higher-performing chips at lower prices, said Joe Draina, associate director with the International Sematech Initiative (ISMI), which is a subsidiary of Sematech, a consortium of leading semiconductor manufacturers.

The transition to a new wafer size coincides roughly with Intel's plans to start manufacturing chips using a more advanced, 22-nanometer process in 2011. The transition to 450-mm wafers will help companies keep pace with Moore's Law, which states that the number of transistors on chips doubles every two years.

"As we start to get to those tight, smaller geometries -- 22 nm and below -- it starts to become more and more attractive and desirable to be out of 300 mm and on to a 450-mm wafer," Draina said. As feature sizes on chips shrink, the 450-mm wafer could double the chip output on the 22-nm process compared to a 300-mm wafer, Draina said

Using the analogy of making a pizza, Willoner outlined the benefit of moving to 450-mm wafers. "It doesn't cost a whole lot more to make a 12-inch pizza than it does to make an 8-inch pizza," he said. "Perhaps it uses a tiny bit more energy, but it's not double the cost, whereas the area of the pizza is double."

The investment required from chip manufacturers will be significant, however. Willoner and Draina both estimated the investment in equipment and standards development for 450-mm fabs to be in the billions of dollars.

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"There's obviously a lot of dispute about that, but then you have to remember this is for the whole industry, so [the investment] gets spread across many companies," Willoner said. The entire industry, including chip makers and manufacturing equipment makers, has to work together to transition to 450-mm wafers, he said.

Moving to the next wafer size will involve almost every supplier and technology required to build chips. Tools such as the furnace and lithography tools need to be developed jointly, Draina said. The delivery of the tools will start in 2009, according to a paper published by the International Technology Roadmap for Semiconductors working group.

The work for Intel to move to 450-mm wafers will be simpler and less costly because a lot of the heavy lifting was done when the company transitioned from 200-mm to 300-mm wafers, Willoner said. "The hurdles that have to be overcome are more incremental rather than revolutionary," he said.

The so-called "wafer boats" became too large for humans to handle after the transition to 300-mm wafers, for example, which led to the development of robots to handle them, Willoner said. New standards were put in place that can be extended easily to 450-mm manufacturing plants, he said.

Still, the larger wafers can make the manufacturing process more difficult, Willoner said.

"Whatever it is we do, we have to do it extremely uniformly across an entire wafer," he said. "We have process steps that put a layer of material that's just a few atoms thick across an entire 300-mm wafer. And we have to do that with incredibly small tolerance [for errors]. Doing that across an even larger wafer ... is much more difficult."