I’ve long been fascinated with the vernacular of the semiconductor industry, which is riddled with acronyms that can often mean different things whether you’re referring to front-end or back-end applications. Additionally, as 3D technologies have developed, so has a whole new set of terms that are evolving right along with the processes. It certainly makes for interesting discussion, as I found out last week at ECTC 2009 (that's Electronics Component Technology Conference).
For example, SoP can mean small-outline-package or system-on-package depending on who you talk to, and before SiP referred to a system-in-package, it was a single-inline-package (not to be confused with a DiP, or dual-inline-package). And before a system-in-package was called a SiP, it was referred to as a MCM, or multichip module. Confused yet? Jeanne Beacham, of Delphon, and I started joking in the buffet line at the conference. “What’s so great about PoP,” quipped Jeanne Beacham of Delphon. “What about MoM?” I laughed, but then again, it’s entirely possible. PoPs made of multichip packages could be called multichip-on-multichip (MoM). They certainly will be able to do lots more than a PoP (I’ll just leave it at that).
What’s more, we toss around terms like FEOL and BEOL (front-end-of-line and back-end-of-line) and FOUP (front opening unified pod) like everyone knows what we’re talking about. (I actually had to look that one up while writing this. I know what FOUPS are; those orange thingies that hold the wafers before and after processing. I just didn’t know what the letters stood for.)
All kidding aside, settling on a set of terms for 3D processes is actually the first step to standardization, notes Eric Beyne, of IMEC. We were discussing how chip and die are used interchangeably, (specifically in reference to die-to-wafer stacking or chip-to-wafer stacking.) and the confusion it causes for those who distinguish between the die and the chip based on whether it’s bare or packaged. Last year, we were told via first could be further distinguished into via-early (before CMOS) or via-middle (after CMOS but before BEOL). Oh great, there’s another one. (For those about to ask, CMOS stands for complementary metal oxide semiconductor. No wonder we don’t usually write that out.) In any case, Beyne says the ITRS (International Technology Roadmap for Semiconductors) is working to standardize definitions, because classification of technologies is required to define a roadmap.
Incidentally, if someone can tell me what IMEC stands for, the drinks are on me. – F.v.T.
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