It is marketing and it does have meaningful connection to the litho features, but the connection is not absolute. For example Samsung’s 5nm is noticeably more power hungry than TSMC’s5nm.
The number has some connection to transistor density, in the sense that a lower number means generally higher density. However there is not any physical feature on the chip that is actually 3nm in length.
I was under the impression that anything under like 10nm was just marketing and doesn’t actually refer to transistor density in any meaningful way?
It is marketing and it does have meaningful connection to the litho features, but the connection is not absolute. For example Samsung’s 5nm is noticeably more power hungry than TSMC’s 5nm.
The number has some connection to transistor density, in the sense that a lower number means generally higher density. However there is not any physical feature on the chip that is actually 3nm in length.
This has been true since the late 90s probably.
Late 90s was 350nm down to 180nm (Known as 0.35um and 0.18um respectively). Things were still pretty honest around then.
2010s is probably where most of the shenanigans started.