Very High Density Interconnect Elastomer Chip Sockets
2006 (English)In: IEEE Transactions on Advanced Packaging, ISSN 1521-3323, E-ISSN 1557-9980, Vol. 29, no 2, 202-210 p.Article in journal (Refereed) Published
The integration of more and more functionality into smaller and smaller form factor electronic products, drives the need for denser chip to substrate interconnect systems. As the number of I/O pins increases, the use of area array chips or packages becomes inevitable. Metal patterned elastomer chip sockets have now been improved to work with contact densities as high as 80000 contacts/cm(2) corresponding to a pitch of 36 mu m. Sockets with 10000 contacts and a 72-mu m pitch have survived more than 400 cycles in air-to-air thermal cycling chambers as well as freezing shocks caused by dipping into liquid nitrogen. Although the daisy chain test circuits breaks for temperatures lower than -50 degrees C and higher than 90 degrees C, they always return to the initial resistance values when entering the normal temperature range. The combination of a gold-to-gold contact interface and the elastic features of the contact bumps makes this socket an ideal compliance layer between bare chips and different types of carrier substrates, reducing the problems caused by thermomechanical mismatch between the substrate and the chip. Bad dies can easily be replaced, since the chip is not soldered or glued to the socket. The size and the possibility to control the geometry of the contacts provides means to maintain a good high-frequency characteristic impedance matching all the way to the chip pad.
Place, publisher, year, edition, pages
2006. Vol. 29, no 2, 202-210 p.
chip-first, chip socket, flip-chip, high-density interconnect, multichip modules, packaging, silicone elastomer, thermal fatigue, thermal stress
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-5462DOI: 10.1109/TADVP.2006.871178ISI: 000237429900001ScopusID: 2-s2.0-33646534157OAI: oai:DiVA.org:kth-5462DiVA: diva2:9835
QC 201101142006-03-142006-03-142011-01-14Bibliographically approved