Custom IC

[jmelson]

Sub-micron digital masks cost a lot, but most simple analogue designs use much coarser processes. They just can't benefit from smaller devices. The mask set might only be a few 10s of k.

No way!  Nobody can get even a simple mask set for under $100K.  And, I doubt you can find any fab that will do 1 um or larger process, there just isn't any demand.  The various services that can do these combined runs have specific processes and design rules they will accept.

Jon

[mairo]

As blueskull have pointed out companies like Diode Inc, ON and ST offer such services.

Some other useful links:
http://www.towerjazz.com/
https://www.globalfoundries.com/
http://kokomogmch.com/
https://www.xfab.com/home/
http://www.semefab.com/
http://isipkg.com/

[coppice]

Sub-micron digital masks cost a lot, but most simple analogue designs use much coarser processes. They just can't benefit from smaller devices. The mask set might only be a few 10s of k.

No way!  Nobody can get even a simple mask set for under $100K.  And, I doubt you can find any fab that will do 1 um or larger process, there just isn't any demand.  The various services that can do these combined runs have specific processes and design rules they will accept.

Jon

You seem to be thinking in digital terms. Think analogue, especially analogue with fairly high voltage transistors. Its a different world, with different players. Most companies dropped their coarse analogue processes years ago, but the niche players who focus on true analogue (as opposed to the people saying they are big in analogue, while their parts are really mixed signal) are still there.

[jmelson]

No way!  Nobody can get even a simple mask set for under $100K.  And, I doubt you can find any fab that will do 1 um or larger process, there just isn't any demand.  The various services that can do these combined runs have specific processes and design rules they will accept.

Jon

OK, maybe I should expand on this.  We use the ON Semi C5 process (used to be AMI semiconductor).  It is a fairly advanced mixed-signal process, perfect for the stuff we are doing.  It does have quite a few more layers than plain CMOS, so high resistance and high capacitance layers can be fabricated.  This does drive up the cost of the mask set.  But, it sounds like this is the kind of process that the OP might need, anyway.  The C5 process is NOT designed for bipolar, the only bipolar function we have is a band gap reference.  People have fabricated other bipolar parts on it, but those parts are not in a library we have access to.

The chips we are doing have very roughly 100K transistors, so quite a bit larger than the OP's project.

Jon