Brian,

I found the following at IPC-7095 ( Design and Assembly Process
Implementation for BGAs ) section 4.4 ...

Circuit board materials have very different warpage requirement. It was not
too long ago
when 1.5% warpage (15 µm per mm) was considered acceptable for printed
circuit boards.
But for surface mount assemblies, maximum 0.75% (7.5 µm per mm) warpage is
required.

Note that is referred to surface mount assemblies in general.

Jorge Dourado de Santana
Maintenance / Process Engr
Microtec - Brazil



> -----Original Message-----
> From: Hunter, Brian C [SMTP:[log in to unmask]]
> Sent: 30 de Novembro de 1999 19:25
> To:   [log in to unmask]
> Subject:      [TN] required PWB co-planarity for BGAs
> 
> I'm trying to find out any information concerning the maximum board
> warpage
> that BGA packages can handle.  Are there any industry standards specifying
> a
> localized flatness at BGA device sites?  Any information would be
> appreciated.
> 
> Thanks,
> 
> Brian C. Hunter
> One StorageTek Drive, MS 9152
> Louisville, CO 80028
> 303.661.5756 phone
> 303.673.3466 fax
> 
> 

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