On Tue, 4 Mar 1997, Gary Peterson wrote:
> PBGAs are classified according to moisture sensitivity just like other
> packages (e.g. Level 1 - Level 6). I don't believe there are any Level 1
> PBGAs on the market (Level 1 implies that you won't get PBGA
> delamination, popcorning, when
> soldering/desoldering the part even if you haven't kept the assembly dry).
Re: PBGA classification
I want to clarify something in Gary's response.
At this point, PBGAs are not included in the IPC-JEDEC joint standard on
component moisture sensitivity (J-STD-020). Nor are they explicitly
covered in the IPC-SM-786A or JEDEC JESD A112.
At a joint IPC-JEDEC task group meeting in Tampa, FL in January, the
topic of BGAs was (again) discussed.
For J-STD-020A, the task group is making a distinction between packages
smaller than 2.0 mm and packages that are thicker than 2.0 mm. It was
(more or less) agreed that more testing needs to be done on BGAs to
determine what level(s) at which they should be classified. However, THIS
DETERMINATION HAS NOT YET BEEN MADE.
Because the specification is used by component manufacturers to inform board
assemblers of the level of moisture sensitivity of plastic parts, it is
possible suppliers are classifying certain types of PBGAs to specific levels.
But, to reiterate, the IPC-JEDEC task group has not yet published a
specification for classifying PBGAs to conventional moisture sensivity
levels.
FYI, the task group is also reevaluating the existing six levels. Reason:
1. Few parts, if any, are classified to the current level 6 (6 hours
exposure). 2. User feedback indicates a new level should be established
between the existing levels 2 (one year) and 3 (one week) to better
reflect current conditions and usage. Any comments regarding this matter
may be forwarded to Doug Sandvick at IPC ([log in to unmask]), Task group
chair Steve Martell at Sonoscan ([log in to unmask]), or myself.
Mike Buetow
IPC
2215 Sanders Road
Northbrook, IL 60062
P: 847-509-9700, ext. 335
F: 847-509-9798
[log in to unmask]
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