Cause and solution of air bubble in BGA

Cause and solution of air bubble in BGA

Bubble in BGA
The bubbles in BGA mainly depend on the adjustment of the temperature curve, is it?
Answer: the causes of the bubble more, let me give you a: too much oxygen paste.

If this is the case, you have to look at the solder paste manufacturers
Answer: not preheating zone, is to extend the warm zone, but this is not necessarily the main reason,

damp PCB pad oxide or organic compounds. The oxidation of element, solder paste and poor are possible,

it is best to do a doe, a a excluded.