"The SRAM vehicle is what we run through evaluation, high-temperature life testing, and the rest of the qualification tests," Sun said. "It certifies that the process is now reliable enough to try running full customer designs." But Sun emphasized that those first design runs—the risk production runs—are done with the full process, not with a subset of the full specs or with an extra-restrictive rule set.
Work will continue after the SRAM runs. Sun said that early customer designs usually have some features that lie outside the design rules, and hence require discussion and perhaps process tweaks. And once customer risk-production wafers are finished, they in their turn will go into the qualification process to be studied and measured. But the SRAM is the major signal that it’s time to start the move to tape-out for the first few designs, send them in, and see what happens.