Common Platform plans route to 28nm
IBM aims to have a high-k metal-gate process for 28nm design rules in place in 2010, around six months after it and other Common Platform companies introduce the 32nm process in the second half of 2009. The companies have enlisted ARM to provide libraries and processors for the metal-gate processes, aiming primarily at the market for mobile Internet devices.
Both the 32nm and 28nm processes will use high-k gate dielectrics and metal gates, with the option of airgap dielectrics in the metal layers to reduce capacitance in designs that need to run at high clock speeds.
Mark Ireland, the vice president in charge of Common Platform work at IBM, claimed: “We started this collaboration about six months ago. We were looking at this new segment for mobile Internet devices, which is expected to outgrow PCs and laptops by 2010. What is different here is that it is not just a physical IP deal. ARM is also developing enhanced IP to leverage high-k, metal-gate processes for best performance at the lowest power.
“The key is to pursue aggressively the high-k, metal-gate properties. That is why we started much earlier with ARM, to ensure the migration is very smooth.”
Tom Lantzsch, vice president of marketing for ARM’s physical IP division, confirmed: “What is unique about this relationship is the point in time when ARM became involved in this process. We produced a test chip earlier this year and we have now done a test chip with some ARM processor cores in it. Historically, we would have got involved much later in the process.”
Unlike TSMC, IBM said the plan is to regard 28nm as a half-node – a simple shrink from designs prepared for 32nm design nodes. “The 28nm half node would follow six months after the introduction of 32nm,” said Ireland.
The current schedule for the Common Platform 32nm process is to start ramping production in the second half of 2009, putting the 28nm introduction in 2010 at roughly the same time as TSMC’s own processes.
Gary Patton, vice president of IBM Semiconductor Research, acknowledged that there are some questions over the claims being made for the latest processes and whether terms such as ‘28nm’ are being applied consistently. TSMC’s commercial 40nm technology has design rules based on a process that was presented as 45nm at the 2007 International Electron Device Meeting (IEDM): “We have had some discussions among ourselves as to what is being described: is it really 28nm or 40nm?”
Although TSMC introduced a process tagged as 40nm, there are no plans for that half node among the Common Platform partners. They intend to jump directly to the 32nm process. “There was an expectation that 40nm would be hot on the heels of 45nm. But the transition to 40nm was somewhat delayed. We believe 45/40mm will be a very short-lived node. Customers will make the move to 32nm high-k, metal-gate quickly,” Patton claimed.