Baking removes moisture that laminates and plastic component packages absorb from the air. Without it, trapped water turns to steam in reflow and causes delamination, measling or popcorning. Bare boards are commonly baked at about 105 to 125 degrees C for a few hours, while moisture-sensitive components follow J-STD-033 times and temperatures for their MSL rating once their floor life has run out.
Those reels sat open for two weeks and they're MSL 3, bake them before they go on the line.
Also heard as
- prebake
- dry bake
- dry out
Related terms
Popcorning
Cracking of a plastic IC package in reflow when absorbed moisture flashes to steam, sometimes with an audible pop.
Delamination
Separation between layers of a board's laminate or between laminate and copper, usually from heat or moisture.
Measling
White spots or crosses inside a laminate where glass fibers have parted from the resin at weave crossings.