Abstract: A method of soldering used in fabricating an electronic circuit device employs an organic material supplied to at least one of the connecting members to be bonded. The connecting members are positioned in an oxidizing atmosphere, and heated in a nonoxidizing atmosphere to remove oxide and/or contamination layers present on the surface of presoldered portions or metallized bonding portions. By this method, fluxless soldering is performed, positional shifts are reduced, and high reliability of the soldering connections with reduction in residues after reflow are obtained.

Abstract: An apparatus comprises a sputter cleaning device, an alignment device operable in atmospheric condition and a heating and soldering device in the form of a belt furnace operable in non-oxidizing or reducing environment. Instead of the sputter cleaning device, a mechanical polishing or cutting device can be used to clean a surface of solder or a member to be bonded or a solder ball plated with gold may be used. An alignment between two members to be bonded is provided by an alignment mark means which comprises a protrusion on a surface of one member and a complimentary recess formed at a center portion of a protrusion means formed on a corresponding surface of the other member.

Abstract: In order to remove oxide film and contamination film on members to be bonded by soldering and solder material therefor corresponding to variation of thickness thereof by sputter-etching in a fluxless bonding method and apparatus therefor, substance emitted from the solder material under sputter-etching using atom or ion is detected and determined whether it is from the solder material or from the oxide film thereon. The sputter-etching is controlled on the basis of the determination to remove the oxide film. Then, the members are aligned in oxidizing atmosphere and soldered in non-oxidizing atmosphere.

Abstract: In a method of soldering for use in fabricating electronic circuit device, after an oxide layer and/or contaminated layer on a surface of a soldering material and members to be soldered thereby is removed by sputter-cleaning with atom or ion, the members are aligned in an oxidizing atmosphere within a predetermined time period and, then, the soldering material is heated in non-oxidizing atmosphere to performe soldering. An apparatus for performing the above method comprises a sputter cleaning device, an alignment device operable in atmospheric condition and a heating and soldering device in the form of a belt furnace operable in non-oxidizing or reducing environment. Instead of the sputter cleaning device, a mechanical polishing or cutting device can be used to cleaning a surface of solder or a member to be bonded or a solder ball plated with gold may be used.