To: Paul Engel who wrote (86460 ) 8/3/1999 10:59:00 AM From: greenspirit Respond to of 186894
Paul and all, Article... Straight talk on 'tape out'... August 3, 1999 ELECTRONIC ENGINEERING TIMES : A few weeks back, Intel Corp. said it had at long last taped out its 64-bit Merced processor. I was curious as to just what exactly "taped out" meant these days. Was there a fixed, industrywide definition, or did a company have some wiggle room in using the term? So I called the experts. According to an Intel company spokeswoman, taping out Merced meant that " the processor design is complete." The database that has all the chip's design information is sent to the fab to begin making masks. Along with pre-silicon verification, "once you get first silicon back, there's more testing, verification and validation," she said. Intel expects to deliver samples during the third quarter, with production shipments in mid-2000. Over at Centaur Technology, Glenn Henry, president and chief architect of the WinChip processor, noted that there are two types of tapeout. In the first, prototyping, the chip isn't production-worthy but is verified to some target (it works well enough, for example, to boot Windows.) This typically is done to verify compatibility, performance or a new manufacturing process. In contrast, production tapeout occurs when a processor has been heavily verified to make sure it works properly in all aspects. (If a mistake is later found, Henry wryly notes that this chip is retroactively called a prototype.) John Mashey, a chief architect at Silicon Graphics Inc., offered insight into the origin of the term. "In the old days, it meant that you wrote the entire database for the chip, in the form needed to make masks (for example, on a tape), and carried it over to the fab," he said. "These days, you normally send it electronically, but it still means you think you have a complete design," he added. "Of course, everybody continues chip simulations and may well send upper-layer fixes along to the fab, proving that hardware is much like software." Fadi Azhari, a group manager at Sun's microelectronics operations, which is getting ready to ship its new Ultrasparc III in volume in the fourth quarter of this year, points out, "When you get first silicon, you test for logical functionality and then for the ability to run at speed." However, Azhari said verification prior to tape out is even more important. "That's where the compute farms [large groups of workstations and servers connected together] really shine," he said. "We test the hell out of a chip. Today, so much of the software is in the front end of the design process, you usually have a very high confidence factor that the silicon will work. But you never know."