Laser Soldering

Where conventional soldering techniques reach their limits

Laser soldering is often applied as selective laser soldering. Selective soldering processes are used in applications where other conventional selective soldering techniques reach their limits. These limits can be for example defined by temperature-sensitive components. The transfer of heat and energy through the laser beam provides the user with many advantages, especially with view to the miniaturization of sub-assemblies or sensitive components.

During the soldering process, the filler metal or alloy is heated to melting temperatures < 450°C by laser. Therefore lasers with lower output powers (typically < 100 Watts) are used to melt the wire material, soldering paste or solder deposits so that it flows in between the two closely fitted joining materials.

For soldering small parts or components within the semiconductor, electronic or optoelectronic device manufacturing or assemblies industry, the diode laser is the right choice. Diode lasers are used for selective soldering because the laser power can be precisely controlled by an analog signal and the heat input into the material is very localized. That is why laser soldering is most advantageous, compared to traditional soldering methods. The process does not damage or input heat into nearby components. That is why even very small electronic components, in the range of a few tenths of a millimeter, as well as heat sensitive electronic parts can be processed. 

Fast power controllability combined with a non-contact temperature measurement to minimize thermal damage make the diode laser an ideal tool for this application. 

Conventional selective soldering techniques, such as e.g. the soldering iron, need a direct mechanical contact between the soldering tool and the solder joint, or the soldering tool has to be very close to the solder joint. Yet, in many cases, this is not possible due to a lack of space. Furthermore, within conventional selective soldering processes, the energy input is either not or is very slowly able to be influenced during the soldering process. 

Benefits at a glance:

  • High precision
  • Low and localized heat input – Soldering of temperature-sensitive components
  • Fast power controllability 
  • Optimized temperature-time profile for best soldering results – The soldering temperature can be regulated according to a pre-set temperature-time profile
  • Non-contact  processing for joining in spaces with limited accessibility
  • Processing of metallic workpieces of very small geometries  
  • Efficient and homogenous heat input
  • No risk of damaging adjacent components
Soldering of circuit boards within the electronic industry

Soldering of circuit boards within the electronic industry

Due to the localized heat input and the precise power control of the laser, the heat input into the workpiece is held at a minimum.


For this application we recommend: Diode lasers with low output powers from DILAS Diodenlaser GmbH, a company of the ROFIN Group