Hi Syed-

Production in flip chip went down to 175 micron several years ago. That was
enough at the time that the substrates became limiters. As Joyce says, the
substrate technology is critical--not just line x space resolution, but via
pitch and flatness. Silicon on silicon is probably significantly more
dense. Keep in mind that the smaller the contact area, the more cleanliness
plays a role. At 200 micron and below pitches, cleanroom is a must and I
would have operators wear masks: An eyelash hair is around 100 microns in
diameter! And then there is spittle, etc.

Wayne Thayer

On Thu, Mar 22, 2018 at 9:07 AM, Ahmad, Syed <[log in to unmask]> wrote:

> We are trying to determine limits on solder or other interconnects for a
> high pin count prototype and need help in identifying suppliers for
> solders, stencil manufacturers, ACAs, ACFs and other options that may help
> us achieve lowest pitch interconnects. All help is welcome. Thank you for
> your assistance. Suppliers may contact me directly on my email.
>
> Syed Sajid Ahmad,
> Research Staff, ECE, NDSU
> Cell 701-200-1674
>