Samsung investors presentation on June 4, 2018 in Singapore talks about an interesting development at the company's S4 fab:
"S4 line provides CMOS image sensor using 45-nanometer and below process node, and we are building EUV line. We started constructing in February this year."
Samsung has been using 28nm design rules in its image sensors for quite a some time. EUV seems to be a natural next step to avoid double patterning limitations on the pixel layout (double patterning is commonly used starting from 22nm node.)
Why does Samsung need 22 nm process?
ReplyDeleteOn the other hand, Sony still may use 90 nm process.
Only Samsung can answer on that with confidence. My guess is that it opens a possibility to use more transistors in small pixel. And more control lines. For example, what about a 2-stage SF, where the first stage with small transistor gives high CG, while the second stage with large nmos makes charging the output bitline much faster?
DeleteThank you very much for your valuable comment!
DeleteBecause they have fabs to fill. I suspect that 22nm is used on the logic layers o stacked sensors. And EUV is not really a way to avoid double patterning altogether, but more of a method for reducing the complexity associated with double patterning of vias.
ReplyDeleteWrong. With 13.5nm EUV wavelength, vias do not need double patterning neither at 22nm node nor at few more process generations.
DeleteAlso, the 20-22nm nodes usually have M1 and, sometimes, more metals double patterning, not to talk about contacts.
The step from 193nm to 13.5nm 'light' is quite a big one - it would indeed be very strange if double patterning was needed.
ReplyDelete