Subject: Re: [IBIS-Users] IBIS bump question
From: Scott McMorrow (scott@teraspeed.com)
Date: Mon Nov 25 2002 - 00:16:35 PST
Eric,
In reality, there is no convention. It depends upon how the flip-chip
package is engineered. In some cases the bump is directly on the pad.
In this case, there is an added capacitance that is often not modeled by
the silicon vendor. Whether it is lumped in with the package or with
the die makes little difference, as long as model is construced
consistent with the approach used.
Another type of flip-chip package uses a redistribution layer, a layer
of additional metalization on top of the original die, that
redistributes the IO pads at the edge of the die back in to where the
die bumps are located. In this case, the redistribution layer can have
significant length and must be modeled as additional package. (This is
especially the case for mixed analog and digital ICs, where great pains
have been taken to isolate the two sections.) The redistribution metal
will have R, L and C characteristics that need to be modeled. In many
cases, this area is not modeled, even in the vendor delivered Spice files.
regards,
scott
-- Scott McMorrow Teraspeed Consulting Group LLC 2926 SE Yamhill St. Portland, OR 97214 (503) 239-5536 http://www.teraspeed.comEric Hsu wrote:
>Hi all, > >For a wire-bond package, the RLC of the bondwire is generally considered >to be part of the package. For a flip-chip package, is there a convention >for how the bump parasitics should be handled? Is the bump to be >considered part of the package, or part of the die(C_comp)? > >Regards, > >|------------------------------------------------------------------ >|For help or to subscribe/unsubscribe, email majordomo@eda.org >|with just the appropriate command message(s) in the body: >| >| help >| subscribe ibis <optional e-mail address, if different> >| subscribe ibis-users <optional e-mail address, if different> >| unsubscribe ibis <optional e-mail address, if different> >| unsubscribe ibis-users <optional e-mail address, if different> >| >|or email a written request to ibis-request@eda.org. >| >|IBIS reflector archives exist under: >| >| http://www.eda.org/pub/ibis/email_archive/ Recent >| http://www.eda.org/pub/ibis/users_archive/ Recent >| http://www.eda.org/pub/ibis/email/ E-mail since 1993 > > > >
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