Applied Varian Readies Trident Implant Tool
By David Lammers
In its first ion implanter product rollout since acquiring Varian Semiconductor, Applied Materials said the high-current Applied Varian VIISta Trident system is optimized for the complex implant recipes employed at foundries.
The mobile SoCs made largely at foundries have multiple threshold voltages and a variety of transistor types, requiring a large number of implant steps. And at the 28nm and 20nm nodes, the shallower source-drain regions require lower energy implants, with a tighter control of dose variability, said marketing director Tom Parrill.
Smart phone SoCs have transistors which must operate with low leakages and multiple threshold voltages, with different source-drain extensions, wells, and halos from one type of transistor to another. “That provides good opportunities in the implant space,” Parrill said.
Also, foundries need to tightly control implant variability so they can provide customers with more chips in the higher performance bins, boosting profits.
The Trident system features an energy purity module, or EPM, which features a very precise angle control. With much of the semiconductor industry moving to vertical transistors, the 0.1 degree angle control in both the X and Y dimensions is needed. While the first finFETs have a relatively modest aspect ratio, the height is expected to increase as time goes on, making angle control ever more important, said Yuri Erokhin, senior director of strategic marketing.
Traditionally, implant has been thought of primarily as a source-drain application, with a trend to go to lower energy as the S-D’s get shallower. Implants are increasingly required to minimize contact resistance, to control strain relaxation, and in the poly or metal gate to control work functions. The variety of implants used at foundries in the lightly doped drain regions is increasing, with three or more species. For mobile SoCs with a large number of devices, “there is a significant increase in the number of implant steps,” he said.
Trident arrives on the market as co-implants are more widely required. Germanium is used to pre-amorphize an area prior to introduction of the dopant. Carbon may be implanted deeper than the dopant to sharpen up the etch profile; a section of the device can be implanted with carbon, supporting a different etch rate than the surrounding area that is not implanted. Chlorine or nitrogen can be used to control oxidation rates.
“We are seeing a significant increase in the number of steps. We saw the need to come up with new implant technology for the 2x nm nodes, particularly for foundry,” Parrill said.
The Vista Trident tool includes a cryogenic option. More implant steps are conducted at low temperatures to reduce damage. (Source: Applied Materials)
Tags: Applied Materials, ion implant, Varian