IBM cleans up silicon wafers

Armonk, N.Y.-based International Business Machines (NYSE: IBM) is getting more out of its semiconductors with a new process to recycle scrap silicon wafers for use in solar panels.

The company's machines use an abrasive pad and deionized water to polish the patterns off of scrap wafers, which are thin discs of silicon material used to imprint patterns that make finished chips for electronics.

Because those imprint patterns are intellectual property, IBM said most scrap wafers cannot be sent to outside vendors to reclaim, so they are crushed and sent to landfills, or melted down and resold.

The company estimated that approximately 3 million wafers are discarded each year, enough to produce up to 57 million kilowatt hours per year in electricity if they were reused as solar panels.

Thom Jagielski, environmental engineer and operations manager at IBM's Burlington, Vt. plant, told the Cleantech Group that the process can "easily, quickly, and effectively and very cleanly, take the IP off the wafers so that the wafer can be reused five or six times as a monitor wafer."

Monitor wafers are used for calibration in the semiconductor manufacturing process.

"Once it's past its specs for being a monitor wafer, we can then pass it on to the solar panel industry and they use it there," he said.

Take a look at the wafers here >>

IBM has a supply agreement with China's ReneSola (LSE: SOLA), which claims on its website to be the world's largest recycler of scrap wafers.

This new process comes at good time for the solar industry, experiencing the effects of a silicon shortage and eager to get its hands on more wafers.

"It's of the highest grade that actually makes their solar panels more efficient, so they're happy to get these things," said Jagielski.

The price tag on those recycled wafers was not disclosed.

Big Blue is already using the recycling system at the Burlington plant, where the technique was developed, and is putting the system in place at its other chip facility in East Fishkill, N.Y.

"It wasn't our intent to create wafers for the solar panel industry, but it was really our intent to be able to re-source or re-use as part of our conservation efforts the volume of wafers that we were wasting," said Jagielski.

The program has already saved IBM more than $500,000 last year by cutting its spending on monitor wafers at its Burlington site, and the company projects ongoing annual savings for 2007 to be nearly $1.5 million, along with an additional one-time savings of more than $1.5 million for reclaiming stockpiled wafers.

In addition to cost savings for chipmakers, the company said solar cell manufacturers could save between 30 percent to 90 percent of the energy they would have needed if they had to process new silicon material.

IBM's polishing system has the potential to clean up the wafers as well as the industry.

"The processes that were used and available in the industry basically involved using nitric and hydrofluoric and other corrosives," said Jageilski.

He said the problems with those systems, which can damage the wafer, is in stopping the process and the cycle time.

"This abrasive pad is self stopping. Because one material is softer than the other, it gets to the silicon layer and just stops. And it's fairly quick."

Another industry process, which can also damage the wafer, is bead blasting, where glass beads are used to pound the patterns off the silicon.

IBM said it plans to provide details of its clean process to other chipmakers, licensing out the technology for use at plants around the world.

"It just seems like a very easy way of recovering some of your raw material costs," said Jageilski.

IBM said its recycling system generates an overall energy savings of up to 90 percent at its plant, since the company no longer has to buy the usual volume of new wafers to meet manufacturing needs.