Santa Cruz, Calif. — When it was first proposed in 2002, it looked like the Oasis IC layout format was a slam-dunk to replace the much more verbose GDSII format. It's been slow going since then —

but the Open Artwork Systems Interchange Standard file format is quietly picking up momentum, observers say.

At a panel discussion during the recent GSPx conference, representatives of Texas Instruments and Intel said that their companies will deploy the Oasis format next year. Tom Grebinski, CEO of Oasis Tooling Inc. and chairman of the Semiconductor Equipment and Materials International (SEMI) data path task force, said that Oasis adoption by integrated device manufacturers is widespread and that companies with internal CAD departments are developing Oasis capabilities.

The question now is when fabless companies will move to Oasis — and that depends heavily on EDA tool support. Fortunately, that support is beginning to pick up. In July, Synopsys Inc. disclosed that its Galaxy design platform and design-for-manufacturing (DFM) tool suite will support the entire Oasis format, which SEMI standardized in 2003.

Tool support
DFM startup Aprio Technologies announced Oasis support in September. Meanwhile, Mentor Graphics' Calibre design rule checking tool accepts Oasis files, and Mentor has a GDS-to-Oasis translator. Oasis Tooling and MicroEDA offer

Oasis-to-OpenAccess translators, and Grebinski noted that work continues to extend OpenAccess to geometric representations using Oasis constructs.

The Oasis format was developed by SEMI with the intent of achieving at least an order-of-magnitude file size improvement compared with GDSII. Other Oasis goals were to remove 16- and 32-bit integer width restrictions, efficiently represent cells with large payloads of flat native geometric figures and facilitate the exchange of layout-related information between design and manufacturing.

"The Oasis format is the driving force behind developing a more efficient mask layout capability," said Grebinski at the GSPx panel. "Anywhere geometric elements are used in the design, Oasis can make the flow to mask-making much more efficient."

Oasis appears to be working as advertised. Carl Vickery, senior member of technical staff at Texas Instruments Inc., said that his company has seen a tenfold reduction in design data size with Oasis compared with GDSII stream, or 20-fold with compression. For very flat, post-optical proximity correction data, however, it's more like a 2.5- to five-fold reduction, he said.

"I'm happy," Vickery said. "It meets or exceeds all other proprietary formats roaming the planet."

"Our interest in Oasis is in having one unified open format that can replace multiple formats today in mask and data preparation," said Bob Gleason, engineering manager at Intel Corp. "With GDS stream, file sizes explode, and we're forced into proprietary formats." He also complained of the GDSII limitations on integer widths, which affect cell names.

Gleason said Intel will begin to use Oasis in 2006 "because we don't want a tapeout crash before we run into an integer limit." Vickery said TI will use Oasis in 2006 because 65-nanometer chips are putting a lot of pressure on the mask data flow.

Representatives of ASML Mask Tools and Toppan Photomasks also indicated strong support for Oasis at the GSPx panel. "The GDSII format breaks internally," said Kurt Wampler, distinguished engineer at ASML Mask Tools. "Fields are restricted to 16 and 32 bits. We are pushing against those limits."

"With Oasis, we are able to reduce disk consumption, increase processing speeds and work with data we couldn't work with before," said Richard Gladhill, advanced mask data prep automation expert at Toppan Photomasks.

One key benefit of Oasis, supporters say, is that it more clearly brings design intent into the manufacturing process.

There is, however, more to be done. "First-generation tools support Oasis readers and writers, but have not yet tapped all the potential Oasis represents," said Mask Tools' Wampler. For that reason, Wampler expects that it will be some time before SEMI goes beyond the current Oasis 1.0 standard.

TI was an active participant in the development of that standard and believes it's enough for now, said Vickery. "I'm not eager to see a revision beyond 1.0," he said. "The fact that it's a standard is very important to us."

Will Oasis completely replace GDSII? No hurry on that, said Wampler. There's no compelling reason, he noted, for GDSII to disappear when only a "moderate" amount of data is required. "The only time you see a migration is when the size of the problem pushes you in that direction," he said.

But Wampler also noted that Oasis is compatible with GDSII. "Anything you can represent in GDS stream can be faithfully represented in Oasis," he said. The switch from GDS to Oasis should be easy, but once it's done, "you'll never go back."

Oasis, however, is not a panacea for the EDA industry. "In the short term, it's a pain for EDA, because it's another format they have to support," observed Intel's Gleason. "But they'll be in a bind if they're restricted to 32 bits." Oasis, unlike GDSII, is 64-bit-compatible.

"Anyone who thinks Oasis is a major cash cow for the EDA industry is sadly mistaken," said Vickery. "Oasis will be like air. It will be ubiquitous enough that you can't charge for it, but you wouldn't want to live without it."

The SEMI P39 Oasis standard can be downloaded at http://downloads.semi.org.