Re: [SI-LIST] : backside metal

D. C. Sessions (dc.sessions@vlsi.com)
Fri, 10 Sep 1999 13:31:28 -0700

Matt Kaufmann wrote:
>
> Hello,
>
> Can anyone comment on the necessity of metallizing the backside of the die
> if we want to ground the backside? In other words, if we want to have an
> electrical connection between the package substrate and the backside of the
> die, is backside metallization required or is the presence of electrically
> conductive adhesive sufficient (assuming the die sits on a grounded die
> pad)?

Die-attach adhesives are good thermal conductors and lousy electrical ones.
Also, the silicon on the backside of a die is usually at least somewhat
oxidized.

Then again, backside metalization is costly and can cause a yeild hit.
Any die-attach that gives good electrical connection may also be
inflexible enough to suffer from differential thermal expansion and
possibly fatigue.

Regards,

Polyanna

-- 
D. C. Sessions
dc.sessions@vlsi.com

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