you mean make up particles? it took some convincing for ladies not wear make up... (you really can't check under the smarch ;-) On Mar 23, 2018, at 2:20 PM, Wayne Thayer wrote: > 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 >>