Abstrakt
Temperature profile is a very important parameter which has a high impact on reliability issues in electronic assembly manufacturing. The wrong shape of temperature profile (temperature/cooling gradients, maximum temperature, preheat together with flux activation) can lead to issues like flux/solder spattering, pad cratering, unwetting, excessive interrmetallic growth, tombstone effect shrinkage etc.
This article deals with influence of latent heat on the shape of temperature profile, which starts to be more attractive due to higher integrity of electronics equipment. The experiments were based of two lead-free solder alloys (Sn96.5Ag3.5, Sn96.5Ag3Cu0.5), which were remelted on the copper pads in continual convection furnace.
The temperature profile, were measured directly under the copper pads. Results shows, that the measured temperature profiles under soldering pads differs against the temperature profile which were measured on the PCB.
Additionally the temperature profiles which were measured under soldering pads differ according to used solder alloys as well.