Altera Cyclone FPGA
Gerd Loch contributed the following advice:
"The device is mounted and bonded to a small pcb made of glass reinforced
epoxy which is also used for "normal" pcb's. This material is hygroscopic and incorporates humidity from the ambient air. During reflow soldering the incorporated humidity explodes and leads to delamination of the carrier pcb and to discontinuities in traces and vias. This effect is called "popcorn effect" It is not so critical if you solder the device manually pin after pin and not heating the complete device in a short time up to 250°C. However you should keep the devices in the aluminized foil which contains some drying material until you are going to solder the device to your board. You will also find a humidity indicator in the foil which indicates if the content of the package has seen too much humidity. If the indicator is still blue you have not exceeded the acceptable level of humidity. If the indicator shows a red colour you should bake the device at 120-130°C for 48hours before reflow soldering."