NDLI: Very high density interconnect elastomer chip sockets

Content Provider	IEEE Xplore Digital Library
Author	Norberg, G. Dejanovic, S. Hesselbom, H.
Copyright Year	1999
Abstract	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 80 000 contacts/cm/sup 2/ corresponding to a pitch of 36 /spl mu/m. Sockets with 10 000 contacts and a 72-/spl 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/spl deg/C and higher than 90/spl deg/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.
Sponsorship	IEEE Components, Packaging, and Manufacturing Technology Society IEEE Components, Packaging and Manufacturing Technology Society
Starting Page	202
Ending Page	210
Page Count	9
File Size	2346644
File Format	PDF
ISSN	15213323
Volume Number	29
Issue Number	2
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2006-05-01
Publisher Place	U.S.A.
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Sockets Integrated circuit interconnections Circuit testing Temperature distribution Pins Electronics packaging Electric shock Nitrogen Thermomechanical processes Size control thermal stress Chip-first chip socket flip-chip high-density interconnect multichip modules packaging silicone elastomer thermal fatigue
Content Type	Text
Resource Type	Article
Subject	Electrical and Electronic Engineering

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