365: Chemistry for Life
DAY 127

Monocrystalline silicon and microchips

Monocrystalline silicon is one of the most important technological materials of the last decades. It uses include computer chips and high-performance solar cells.

Contributed by: Runchen Lai
Credit: iStock

People everywhere can now watch television on a mobile phone, carry thousands of songs in a back pocket, or use a personal digital assistant like a desktop computer. The electronics industry has entered a golden age of mass-marketed devices that do extraordinary things.

At their core, these consumer gadgets feature extremely advanced microchips that are produced with significant assistance from the chemical industry. And products now under development will require many new materials, as well as chemistry know-how. Combine this scenario with a rebounding market for semiconductors that could grow by 30% this year, and opportunities abound for chemical firms.

“There’s far more complexity in terms of materials,” says Cathie Markham, Dow Chemical’s director of R&D for electronic materials. “The material platforms are all cascading; you see materials that were used in the printed circuit board going into semiconductors.” The performance requirements for semiconductor applications demand modifications to materials formulations and chemistries, as well as higher purities, she adds. And because of these different formulations, Dow’s product lineup has been expanding to keep pace with the semiconductor industry’s surging need for new materials, she notes.

The proliferation of new materials has been spectacular, confirms John Doering, director of deposition technologies at ATMI, a firm that specializes in developing and manufacturing semiconductor chemicals. Whereas five years ago semiconductors were made of only about a half-dozen materials, he says, nowadays “it looks like half the periodic table” is being used to achieve the desired electrical functionality under the thermal processing conditions that are needed during manufacturing.

Turning a virgin silicon wafer into a semiconductor involves three steps. As Doering puts it, “Deposition is about putting the material on the wafer, lithography is about deciding where you want to leave the material or where you want to take it away, and etching is about removing the material that you don’t want.”

 

Visit Chemical & Engineering News to read more about the chemistry of monocrystalline silicon and microchips.

 

Excerpted with permission, Chemical & Engineering News
Copyright © 2010 American Chemical Society