Hello Richard,

I might be wrong but I don't think one can call a "slit" or a gap
between a surface and solder a void. the situation you refer to is
rather a solderability issue with a QFN pad, but not voiding one.

And if that is the case then, yes, you are absolutely right it's not
detectable by X-ray. however, if it's a solderability issue then  it
should spread over the affected batch, not just one QFN and it's
always the best practice to qualify (by X-sectioning) any new batch of
any or at least the most vulnerable components.

-- 
Best regards,

Vladimir Igoshev. PhD                          mailto:[log in to unmask]

SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca

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