Is it possible to get fab using caravel with exposed electrodes? I am aiming to use chips for biological applications, so I need a surface that interacts with the outside world. I've gotten contradicting messages from efabless and outside designers about caravel (they say "The mandatory "Caravel" pad ring occupies the entire top layer of the chip as well as a ring around the edges. It hermetically entombs the design area that you control.", whereas efabless said they supported bare die when I asked "can we get silicon fab with electrodes exposed?"). Is this online person wrong? Or through my ignorance in chip fab am I missing a key detail here? Thanks

From the ChipIgnite program you can get bare die; from the Open MPW program, you can't. If you submit something on a ChipIgnite shuttle run, then the pads will be exposed, along with any other places on the chip that you place overglass cuts (i.e., you can place your own pad cuts internal to the user area).

Ah, so if I understand this correctly, with ChipIgnite we could expose the electrodes on the top of the chip (with the normal pads on bottom for communication)

I don't understand that comment. As a standard CMOS process, metallization will be on one side. There are existing pads that are normally wirebonded out. I would expect that you post-process by adding additional (biologically inert) layers on top of the existing aluminum pads.

Thanks! Answered question