The application of semiconductor diode lasers to the soldering of electronic components

Work being carried out at the University of Hull into the application of high power laser diodes to the soldering process is described. The commercial availability of semiconductor diode lasers has brought an exciting new soldering tool to the manufacturers of electronics assemblies: trends in electronics assembly are to increasingly high-density interconnections and increasing device functionality. Packages are reducing in size and pin-out counts are increasing. Currently 0.010-0.016 inch lead pitch devices are being introduced by many manufacturers. Lasers can be used with advantage in the soldering of such fine and precise devices and high-power semiconductor laser diodes can be used to build compact, flexible and controllable soldering units. With computer control of the power and duration of the laser energy it is possible to ensure consistent and reliable soldering. To achieve this, however, the various parameters involved in the laser beam-solder assembly interaction need to be carefully defined. This paper reports on our identification of these parameters and the salient design features of an automated diode laser soldering system.