Cobalt Can Solve Computer Chip Problems

The Wall Street Journal’s Digits reported that Applied Materials Inc. (NASDAQ:AMAT), which makes machines that manufacture semiconductors, plans to use cobalt to wall off microscopic copper wires that connect the transistors in computer chips. Tantalum is the material that is usually used.

As quoted in the market news:

As transistors get smaller, many more of them can be packed onto each chip–billions, in fact. Connecting them requires grids of wiring that are increasingly large and complex; the copper strands contained in all the chips fabricated on a typical 12-inch semiconductor wafer can measure 100 kilometers, Ramamurthy says.

But engineers run into problems as they shrink the size of those wires, which are formed by filling up furrow-like channels with copper. Like a large volume of water forced into a smaller streambed, current moves faster and causes impacts akin to the rocks or boulders moved by a rushing torrent, Ramamurthy says. The current can shake loose copper atoms, creating gaps called voids that lead to short circuits that cause chips to stop working correctly, he says.

The trick is to coat the sides of the copper-filled trenches with a thin film of cobalt instead of tantalum, as well as capping the channel with another cobalt layer, [Sundar Ramamurthy, Applied’s vice president and general manager of metal deposition products] says.

Click here to read the full Digits report.