What is the type of pad surface finish prior to BAll placement? Ni/Au, HASL,
OSP...
we also had recently problems with breaking between solder and CSP pad from
an japanese manuf.
They have just (!) to redevelope their Ni/Au process.
Regards
        Wolfgang Nuechter

> Dr. Wolfgang Nuechter
> *     Robert Bosch GmbH, Postfach 10 60 50, D-70049 Stuttgart, Germany
> *     +49 711/811-7034 (BCN: 9020-7034) Fax: +49 711/811-7956, -266260
>  e-*  mailto:[log in to unmask]
>
>
> ----------
> Von:  Mark Austin[SMTP:[log in to unmask]]
> Antwort an:   TechNet E-Mail Forum.;Mark Austin
> Gesendet:     Montag, 28. September 1998 18:00
> An:   [log in to unmask]
> Betreff:      Re: [TN] ASSY: BGA FAILURES
>
> Dear Jim
>
> This may be a very stupid idea, but what about using ultrasound?
>
> I belive they use ultrasound to detect microscopic fractures in mechanical
> assembly's and the joint between the CBGA and the solder ball is
> mechanical.
>
> I dont know what the ultrasound would do to the chip or the wire bonds but
> it may be worth some more enquiries to the component manf.
>
> I would be very interested to read how you got on.
>
>
> ===== Original Message from TechNet@PAT [log in to unmask] (TechNet E-Mail
> Forum.) at 28/09/98 13:50
> >Hi, Technet:
> >
> >We've been experiencing approximately 5% failures on 228 ceramic BGAs for
> open
> >circuits.  Evaluation of the suspected components revealed a ball
> attachment
> >problem to the component solder pad.  We've seen anywhere from partial
> wetting
> >up to total non-wetting of some of the component pads.  These devices are
> >"dimpled" BGAs, where the pads are recessed approximately .006" below the
> >bottom surface, so it is conceivable that the solder balls are just held
> in
> >place, without any metallurgical bond to the component metallization.
> >
> >Can anyone offer any suggestions as to how we can inspect these
> components to
> >detect the solder defect prior to assembly?  X-ray doesn't work, and I
> don't
> >think laminar x-ray would either.  Are there any other inspection systems
> that
> >could be used?
> >
> >Thanks in advance,
> >
> >Jim Marsico
> >AIL Systems Inc.
> >(516) 595-5879
> >[log in to unmask]
> >
> >
> >################################################################
> >TechNet E-Mail Forum provided as a free service by IPC using LISTSERV
> 1.8c
> >################################################################
> >To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in the body:
> >To subscribe:   SUBSCRIBE TechNet <your full name>
> >To unsubscribe:   SIGNOFF TechNet
> >################################################################
> >Please visit IPC's web site (http://www.ipc.org) "On-Line Services"
> section for additional
> information.
> >For technical support contact Hugo Scaramuzza at [log in to unmask] or
> 847-509-9700 ext.312
> >################################################################
>
>
> Mark Austin (Process Engineer)
> ACW Technology Ltd
> Hylton Road
> Petersfield
> GU32 3XX
>
> TEL - (01730) 300000
> FAX - (01730) 266045
>
> DDI - (01730) 304401
> MA @ ACW.CO.UK
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in the body:
> To subscribe:   SUBSCRIBE TechNet <your full name>
> To unsubscribe:   SIGNOFF TechNet
> ################################################################
> Please visit IPC's web site (http://www.ipc.org) "On-Line Services"
> section for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
> 847-509-9700 ext.312
> ################################################################
>

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################