Chaim, my answers are included with your questions below. I frequently get requests
for clarification of this section. The committee developing the revision has made a
little change to this section. The words that will be in Revision are as follows:
6.5.1 Excess Solder * Solder Balls/Splashes
Target - Class 1,2,3
-No evidence of solder balls on the printed wiring assembly.
Acceptable - Class 1
Process Indicator - Class 2,3
-Solder balls that are within 0.13 mm of lands or conductors, or exceed 0.13 mm in
diameter.
-More than five solder balls/splashes (0.13 mm or less) per 600 mm2.
Defect - Class 1,2,3
-Solder balls/ splashes violate minimum electrical clearance.
-Solder balls/ splashes not encapsulated or entrapped (e.g. no-clean residue,
conformal coating), or not attached to a metal surface.
Note: Entrapped/encapsulated/attached is intended to mean normal service environment
of the product will not cause a solder ball to become dislodged.
==========================================
APEX - the industry's premier trade show in Electronics
Manufacturing, March 12-16, 2000, Long Beach, California.
More information on website www.ipc.org/html/apex.htm
-----------
Jack Crawford, IPC Director of Assembly Standards and Technology
2215 Sanders Road, Northbrook IL 60062-6135
[log in to unmask]
847-790-5393
fax 847-509-9798
>>> Krief Chaim-BCK001 <[log in to unmask]> 05/10/99 07:49AM >>>
Hello Technetters,
This is the IPC definition Regarding solder ball acceptability, IPC-A-610B,
Nonconforming Defect - Class 1, 2, 3 Solder balls/splashes violate minimum electrical
design clearance, or are not encapsulated imbedded in a permanent coating or attached
to a metal contact.
Nonconforming Process Indicator - Class 1, 2, 3 Solder balls/splashes which are
within 0.13 mm of lands or traces, or exceed 0.13 mm in diameter.
More than 5 solder balls/splashes (0.13 mm or less) per 600 sq. mm.
Please explain the meaning of the above sentence.
Does (0.13 mm or less) related to the Solder Balls diameter or 0.13 mm of lands or
traces.
>>Both. When referring to the size of the solder balls they become process indicators
when they are greater than 0.13 mm in diameter regardless of how close they are to a
conductor. When referring the distance from a a land or trace, any size solder ball
closer than 0.13 mm is a process indicator. It's a double whammy if a solder ball
larger than 0.13 mm is closer than 0.13 mm to a land/trace, but a process indicator
is a process indicator no matter how many reasons it's a process indicator.
Dose it mean that 5 solder balls/splashes that are bigger then 0.13 mm are acceptable
or it mean that 5 solder balls/splashes that are more then 0.13 mm of lands or traces
are acceptable.
>>Solder balls of any quantity greater than 0.13mm in diameter are process
indicators, as stated above. Solder balls of any size or quantity closer than 0.13
mm are a process indicator. More than five small (less than 0.13 mm) solder balls
that are more than 0.13 mm from a land/trace are a process indicator. Less than five
small (less than 0.13 mm) solder balls that are more than 0.13 mm from a land/trace
would be acceptable IF they ARE permanently encapsulated/imbedded in some kind of a
permanent coating material, and IF they do NOT violate minimum electrical design
clearance.
Maybe we gut it all wrong please advice.
>>IPC technical staff is pleased to assist with understanding of the requirements.
If it is beyond a basic understanding we enlist the assitance of the committee
leaders.
Cordially,
Jack
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