Embedded Fibers Enhance Nano-Scale Interconnections

While the dens­ity of chip-to-chip and chip-to-pack­age com­pon­ent inter­con­nec­tions increases and their size decreases the ease of man­u­fac­ture and the inter­con­nec­tion reli­ab­il­ity are being reduced. This paper will intro­duce the use of embed­ded fibers in the inter­con­nec­tions as a means of address­ing these issues.

Flip chips bumps are evolving from large solder balls down to small thin cop­per pil­lars. Some cop­per pil­lars are solder capped and use a thermo-com­pres­sion reflow attach­ment pro­cess. Smal­ler dia­met­er cop­per pil­lars, while desir­able by users, present a sig­ni­fic­ant chal­lenge to assem­blers and reli­ab­il­ity issues for end-users.

Nano­struc­tures in the form of car­bon nan­otubes have been eval­u­ated for years. The recently cre­ated a means of grow­ing metal­lic car­bon nan­ofibers, CNF’s, to micro bumps which are sol­der­able. When embed­ded with solder the fiber bumps pro­duce robust com­pon­ent inter­con­nec­tions which can be less than 10 um in dia­met­er and up to 20 um high. Attach­ment of the fiber micro bumps uses con­ven­tion­al thermo-com­pres­sion bonding.

Res­ults from the most recent eval­u­ations will be presen­ted indic­at­ing elec­tric­al per­form­ance and show­ing ease of manufacture