David Lanzendörfer schreef op za 11-04-2020 om 15:57 [+0100]:

Hi Staf

Now I'm getting what you're trying to tell me!

Good point!

However. Double patterning is possible in this way:

https://www.techdesignforums.com/practice/guides/double-patterning/

This already gives us the possibility to squeeze a bit more resolution out

of the stepper. Right?

The LELE is the generic technique for doing double patterning and what I was also hinting at but as name says it involves 2 litho and 2 etch steps.

The SADP looks nice when looking at cross sections but has big restrictions on what one can print. It basically can only print lines of one fixed size and they are formed around the border of the first pattern. This means that you likely need a third litho + etch step to remove the lines in places where one does not want them and possibly a fourth litho + etch step if one wants to also have lines with a bigger width. This technique is mainly used for NAND Flash where you have these long parallel lines, AFAIK it is not used for random logic.

greets,

Staf.