PBGA可靠性焊接影响因素THE EFFECTS OF SOLDER JOINT VOIDING ON PLASTIC BALL GRID ARRAY RELIABILITY Donald R. Banks, Terry E. Burnette, Yeuk-Chow (Dennis) Cho, William T. DeMarco, and Andrew J. Mawer Motorola Semiconductor Products Sector Austin, Texas [1]. This work attempts to address the question through direct experimentation. Voids in solder joints have many causes. Eutectic solder shrinks about four percent during solidification. The interior of a joint would be expected to have a void simply because it is the last part of the joint to solidify. Outgassing of the printed circuit board or the PBGA substrate is another possible void source. Moisture, incomplete laminate curing, or metallization contamination can supply gases that may be entrapped in a solder joint [2]. Flux volatilization in solder paste or cr……