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Microcontrollers for low-end hobbyist use, household appliances, or industrial use don't necessarily need state-of-the-art nodes. Price and bulk availability ma
by samus 3y ago
Microcontrollers for low-end hobbyist use, household appliances, or industrial use don't necessarily need state-of-the-art nodes. Price and bulk availability matter. And high-end nodes actually have disadvantages in these areas as their supply is limited, as several car makers quite recently had to learn the hard way.
Also, it doesn't really make sense to use high-end nodes for low-end controllers because the smaller the chip gets, the higher the packaging cost as it gets more difficult to handle. Microcontroller designers already throw in tons of extra features because there is now too much space available.
Finally, it is easier to build up and certify a supply chain for an ancient node than for a high-end node as all the patents have expired by now and the process is much more rugged. In the current political climate, supply chain robustness and auditability might trump pure cost for some applications.
- dragontamer 3y agoMy understanding is that 200mm / 8-inch wafers on the older nodes is a literally dying technology. It's inefficient, it's costlier, it's just worse in all possible attributes. 180mm, and other similar nodes from the late 90s, are 200mm wafers. And since area is radius-squared, the modern 300mm wafer contains more than double the mm^2 and therefore double the chip-area. Except 28nm process also shrinks the transistors by many magnitudes. It's infeasible for 180mm to remain cost efficient against 40nm, 28nm, or 22nm. Top-of-the-line 5nm or 3nm are far more expensive. But a 10+ year old 40nm fab has most of it's one-time-costs already paid for and overall has a more cost effective process in general due to the upgrade to 300mm wafers.
- samus 3y agoThanks for the reply. I was not necessarily arguing for the ancient processes, but for the existence of tradeoffs between the process generations that don't instantly make the older processes obsolete. However, depending on how important having domestic chips is rated, seemingly obsolete processes might still have the advantage of lower setup cost.
- adgjlsfhk1 3y agothe leading edge nodes will have a substantial cost premium, but about 1 decade behind leading edge is the cheapest per transistor because when you go back further the increase in transistor size makes them less efficient to manufacture.
- samus 3y agoThe old nodes are cheap because the investment has been fully paid off. There are only running costs and maintenance remaining. However, expanding productions of older nodes will be more expensive, especially if the equipment is not available in bulk anymore. Probably not as expensive as a new node though.
- adgjlsfhk1 3y agoRight. pre EUV, the only reason older nodes were cheap is because you didn't have to build a new fab. Now though, EUV machines are expensive enough that it looks likely that the pre-EUV nodes may remain cheaper pretty much indefinitely. 22/14nm is pretty power efficient, a lot simpler to make.