There are countless ways to increase crop yields.
TSMC began mass production of chips based on its first N3 (3nm-class) fabrication process several months after Samsung Foundry began high-volume manufacturing using its 3GAE (3nm-class, gate-all-around early) node, but TSMC’s yields are significantly higher, according to a report by Business Next citing various industry analysts and experts; however, TSMC has not confirmed the reports.
According to semiconductor analysts and experts interviewed by Business Next, TSMC’s N3 yields could be as low as 60% to 70% or as high as 75% to 80%, which is quite good for the first batch. Meanwhile, financial analyst Dan Nystedt tweeted that TSMC’s current N3 yields are comparable to N5 yields early in the company’s ramp-up, which, according to the media, could reach up to 80%.
In contrast, Samsung Foundry’s 3GAE yields in the early stages fluctuated between 10% and 20% and have not improved, according to a report citing unnamed industry sources. In addition, the quality of chips was extremely variable, the report states.
There are several noteworthy aspects of TSMC’s current N3 yields, despite the wide range of estimates. First, it is unknown whether yields are calculated for commercial wafers passing through TSMC’s Fab 18 or for commercial and shuttle (test) wafers containing various intellectual property belonging to TSMC’s customers. Second, only TSMC and its customers are currently aware of the exact yield rate of commercial or shuttle wafers. Thirdly, if we only consider commercial wafers, TSMC’s N3 is currently used to produce a small number of designs for early adopters, although this is based on market rumors.
Initial yields could be as high as 80%, which is not surprising considering that TSMC tends to develop its cutting-edge production technologies with Apple’s — its largest customer and its alpha client for cutting-edge nodes — requirements in mind and that the Cupertino, California-based tech giant tailors its designs to TSMC’s capabilities. Similarly, a yield rate of 60% for a chip (or chips) intended to power mass-market products may not be particularly high.
Since the number of N3 designs TSMC produces commercially is limited (we speculate that it barely exceeds three ICs) and yields-related data is a closely guarded trade secret of the foundry and its clients, we are unable to determine whether TSMC’s N3 yields are high or low.
In fact, for the same reason, we would avoid comparing TSMC’s early N3 yields to Samsung Foundry’s early 3GAE yields.
In addition, rumors surrounding the initial N3 node (also known as N3B) suggest that Apple may be the only company to adopt this technology, as other developers are expected to use N3E, which has an enhanced process window. In the meantime, early N3 yields may not apply to N3E (and other nodes from the N3 family of technologies), and this process technology is something that the entire industry should be concerned with, as it will be widely adopted.
Modern semiconductor production technologies involve tens of thousands of process steps that are dependent on materials, fab equipment tools, and process recipes. Therefore, there may be thousands of ways to increase or decrease yields, which is why it is essential to have a thorough understanding of how each factor influences the others. Since TSMC’s N3 (N3B), N3E, N3S, N3P, and N3X are very different manufacturing technologies, early N3 yields are indicative of the success of other nodes but are not a guarantee (or not as successful).
Keep in mind that TSMC did not comment on the news story (and that they will never comment on yields), so all numbers should be taken with a grain of salt.