Burlington (VT) – IBM said that it has found a way to repurpose scrap silicon wafers that otherwise would end up in landfills.

SRAM dies on a wafer

Using a “specialized pattern removal technique”, IBM claims that it can convert semiconductor wafers to a form used to manufacture silicon-based solar panels. This invention could be significant as not all wafers are actually used to create chips for computers, mobile phones, video games, and other consumer electronics: More than 3% of the 250,000 wafer starts every day are estimated to be discarded, resulting in more than 3 million scrap wafers each year: Typically, these wafers are not repurposed, but shredded - to protect intellectual property – and dumped into landfills.

IBM says that a “new reclamation process” allows the company to remove the intellectual property from the wafer surface – enabling either a reuse in internal manufacturing calibration as so-called “monitor wafers” or for sale to the solar cell industry. The process is currently in use in IBM’s the Burlington, Vermont, facility and currently being implemented at IBM's East Fishkill, New York, semiconductor fabrication plant, as well. The company indicated said that it plans to provide details of the new process to the broader semiconductor manufacturing industry in the future.
 
IBM did not provide any information on what share of the scrap wafers can be repurposed, how much energy it takes to remove the intellectual property from its discs and how much energy is needed to make the transition to the solar panels. However, the firm noted that depending on how a specific solar cell manufacturer chooses to process a batch of reclaimed wafers, a company “could save between 30 - 90% of the energy that it would have needed if it had used a new silicon material source.”

IBM itself said that the program has resulted in reduced spending on monitor wafers and increased efficiency in IBM’s wafer reclaim program. According to the manufacturer, the estimated ongoing annual savings for 2007 “is nearly $1.5 million” and the one-time savings for reclaiming stockpiled wafers is estimated to be more than $1.5 million.

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