CNET has a report on what chipmakers are doing what their scraps. In the past firms like TI tried selling them to local hobbyists for cheap prices but nowadays they are selling them to the solar industry:
But as demand for processed, high-grade silicon substrates began to escalate in 2004, TI re-examined its policies and started selling its scrap wafers to makers of solar energy gear.
Now, the company sells about 1 million scrap wafers from its fabrication facilities in Texas, Germany and Japan to the solar industry, where they get converted into solar cells. Revenue from the program comes to around $8 million a year, Hayden said.
"The decision is to either throw them away or recycle them," he said. "One of the major priorities for us is to make everything as ecologically friendly as possible."
Next, TI will expand the recycling program to include scrap silicon from its testing and packaging facilities in Taiwan and elsewhere. It is also looking at ways to extract and recycle silicon out of the water used in its manufacturing processes.
Intel and Advanced Micro Devices have similar programs. Intel says it sells about 1 million scrap wafers to the solar industry a year.
The term "scrap" is a bit of a misnomer. These wafers are made of high-grade crystalline silicon. Because the semiconductor industry requires slightly higher standards of purity than are required in the solar cell industry, the material can be reused for solar cells.