RF power, wafer chuck key to new Lam etch tool

by Debra Vogler, senior technical editor, Solid State Technology

July 16, 2008 – Lam Research recently debuted the third generation of its Kiyo product line, the 2300 Versys Kiyo3x conductor etch series, targeting applications including double-patterning, high-k/metal gate (HK+MG), hardmask open, shallow trench isolation, and strained silicon.

According to Richard Gottscho, group VP & GM of Lam’s etch businesses, the company continued its focus on improvements in wafer temperature control that enable radial tuning for edge control and profile shaping. These improvements, along with a design that enhances reactor symmetry, result in CD uniformities of 1nm, 3σ variation, he said, in a pre-SEMICON West interview with SST.

Proprietary pre-coat and post-etch chamber clean techniques enable every wafer to see the same environment. For complex film stacks such as HK+MG, the 2300 Versys Kiyo3x provides multi-film etch capability in a single chamber, which Lam believes provides a productivity advantage over a two-chamber approach.

Previous iterations of the Kiyo tool addressed a variety of asymmetries: mechanical, RF power, and those associated with electromagnetics such as power coupling, power return, ambient shielding, etc. For the third generation of the product family, though, Lam focused on the reactor’s “electrical” symmetry — e.g., how RF power is applied. “The electrical design is actually quite subtle when you’re dealing with dimensions of 1nm and RF frequencies in the tens of MHz range,” said Gottscho.

Of particular note is the wafer chuck in the newest product family is that it has more than two temperature zones (previous versions had only two). Also, edge performance is improved to 2mm exclusion with a 50% wider window for step-by-step dynamic temperature changes.

Because the Kiyo product family is modular, customers can upgrade their installed base or change their product mix by selecting from a suite of options depending on the stacks that they are etching. Gottscho told SST that a typical physical conversion can take less than one shift in a fab, although some users would probably take down the tool longer than that to do the qualification testing.

According to Gottscho, almost all of Lam’s leading-edge customers have the beta version of the Kiyo3x hardware that is shipping now, and the tools are being accepted for use in qualifying next-generation devices. The company anticipates that end users will start small volume production later this year, with ramp-ups occurring throughout 2009. — D.V.


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