Precision Repair of Defective Soldering Joints with Gold Nanoparticles and a Low-Power Laser: Tackling a very old problem with new technology

Traditionally, the ubiquitous soldering iron is the tool of choice-perhaps the only tool of choice-when it comes to fixing a defective soldering joint. Continuous miniaturization of consumer products during the past two decades, however, has led to printed circuit boards (PCBs) and multichip modules that are very densely packed with components. The interlead spacing in many integrated circuit chips is typically 0.5 mm, and the inter component spacing on most PCBs is even less. Reworking a single defective soldering joint on a PCB has therefore become very challenging (it is practically impossible to touch a joint with a soldering iron without also touching the neighboring joints). For this reason, we have recently developed and published a totally new technique for reworking/repairing defective soldering joints in PCBs and multichip modules [1]. The technique is not based on traditional soldering methods or tools but rather on the remarkable properties of gold nanoparticles (GNPs).