Dear Technetters,

Could any body help me with explaining the acceptable (Class 1) and process indicator (Class 2,3) level of solder ball in IPC-A-610C, section 6.5.3.1 or 12.4.10? 
    * "Entrapped or encapsulated solder balls that are within 0.13mm [0.00512in] of lands or conductors" => We do not need to control the minimum electrical clearance, don't we?
    * "Entrapped or encapsulated solder balls that are exceed 0.13mm [0.00512in] in diameter." => It is acceptable if the diameter is over 0.13mm.
    * "More than five solder balls/splashes (0.13mm [0.00512in] or less) per 600mm2 [0.93in2]." => How about the upper limit of solder ball quantity?

About the defective level (Class 1,2,3), my understanding based on the explanation in the book is that if our solder ball does not violate minimum electrical clearance and is entrapped or encapsulated or attached to a metal surface, it is acceptable reagardless of diameter, the location and the quantity of the ball. Is it correct?

Every information is highly appreciated.

Thanks.

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NGUYEN QUOC KHANH <[log in to unmask]>
FUJITSU COMPUTER PRODUCTS OF VIETNAM, INC.
PCBA MANUFACTURING DEPARTMENT-PCBA ENGINEERING SECTION