关键词: 无铅焊 汽相焊 回流焊 焊接故障 高热容量印制板

Abstract:

A high-heat-capacity printed circuit board （PCB） is soldered in the vapor phase soldering process by using the self-made low melting point Sn-Bi-X a lloy as a solder. Various insurmountable soldering defects in the high-temperature lead-free fellow soldering process are successfully resolved. Aiming at the problems occurred in the reflow process, a test board of 20 layers containing the 0402 chips with low-heat-capacity and large-sized BGA chips with high heat capacity is specially designed by the authors. The temperature profile can be accurately controlled by using the particular SVP function of  the vapor phase process, the leads of various chips can keep the heat matched all the time while they are being soldered. Therefore, the excessive soldering phenomena of low-heat-capacity chips and the cold soldering phenomena of high-heat-capacity chips are avoided.

Key words: lead-free soldering, vapor phase soldering, reflow soldering, soldering defect, high-heat-capacity PCB