IBM has begun to recycle the waste silicon from one of its chip manufacturing plants to provide a source of silicon wafers for making solar panels.
A new process introduced in its Vermont manufacturing facility has enabled IBM, to repurpose scrap semiconductor wafers - thin discs of silicon material used to imprint patterns that make finished semiconductor chips for computers, mobile phones, video games, and other consumer electronics - to a form used to manufacture silicon-based solar panels. The new process uses a specialised pattern removal technique to reclaim the silicon.
The process enables these wafers to be made available either for reuse in internal manufacturing calibration as "monitor wafers" or for sale to the solar cell industry. IBM has estimated the process would resulting annual savings of £725 million by enabling the company to reuse the spent silicon.
The process is now being deployed at IBM's East Fishkill semiconductor fabrication plant.
IBM has estimated that up to 3.3% of the 250,000 wafers used by the semiconductor industry each day are scrapped. In the course of the year, this amounts to approximately 3 million discarded wafers. Because the wafers contain intellectual property, most cannot be sent to outside suppliers to reclaim so are crushed and sent to landfills, or melted down and resold, IBM said.
The wafer reclamation process produces monitor wafers from scrap product wafers. IBM said this generates an overall energy savings of up to 90% because repurposing scrap means that it no longer has to procure the usual volume of net new wafers to meet manufacturing needs. When monitors wafers reach end of life they are sold to the solar industry. Depending on how a specific solar cell manufacturer chooses to process a batch of reclaimed wafers - they could save between 30% and 90% of the energy that they would have needed if they had used a new silicon material source, IBM said.