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