Surface mount connectors are usually subjected to higher processing temperatures than through-hole connectors. This is because of a basic difference in the soldering processes used, and one of the major technical obstacles that had to be overcome prior to the development of truly surface mountable connectors.

Through-hole connectors are usually wave soldered. In this process the board is passed over a wave of liquid solder so that only the metal leads are heated above the solder melting point. Surface mount boards are heated in vapor phase (VP), infrared (IR) or infrared-convection (IC) ovens to reflow screen printed solder paste. Since the entire assembly must be heated above the solder melting point, and held there for sufficient time for the leads and pads to be wet by the solder, surface mount connectors must be able to withstand 230°C for 30 to 60 seconds. In some cases, IR or IC soldering processes can expose the connectors to temperatures as high as 260°C for 10 seconds.

While most surface mount connectors are designed to satisfy these process requirements, the amount of time and temperature should be minimized to only that which is required to wet the connector leads and printed circuit board pads. Extended time above the solder melting point can damage the board and sensitive components and form excessive intermetallic compounds in the solder joint, causing poor solderability and even solder joint failure.