Laser ablation is a process that removes layers of materials from the surface of a solid object while leaving the base material intact. It offers built-in advantages that often make it a preferred process versus two other technologies: chemical etching and solder damming.
Chemical etching removes unwanted material, such as conductive material or paint, by immersing the object in a bath of corrosive liquid. How much material is removed (and to what extent the base material is left undamaged) is often determined by trial and error and involves factors such as the concentration and composition of the chemical, the material to be etched and the temperature.
Solder dams are created using a different process and for a different reason: to prevent solder on a PCB from flowing into areas where it shouldn’t and causing electrical shorting. To prevent shorting, PCB designers install dams formed by glass or other dielectric. The dams are created with traditional methods of printing and firing glass or other dielectric — a process that can be costly in terms of processing time, labor and scrap materials.
Rather than use a corrosive chemical bath, laser ablation removes unwanted material by irradiating the surface with a (usually pulsed) laser beam that heats the material and causes it to evaporate or sublimate. How much material is removed can be precisely controlled and varies based on the amount of laser energy applied per pulse, the pulse rate and the material’s optical absorption characteristics.
Compared to chemical etching, the advantages of laser ablation include:
While solder dams control solder flow by steering the solder where it is supposed to go, laser ablation controls flow by using a laser pulse to create a trench around solder pads. That way, solder does not flow through the trench, contacting nearby conductors and causing a short.
Compared to solder dams, the advantages of laser ablation include:
Of course, whether your goal is to remove unwanted material from a surface or to control solder flow, your particular application needs to be viewed in terms of its specific requirements. That’s why we recommend getting in touch with us first, before you commit any of these technologies, for a fast, free upfront assessment of which technique might be best and why.
Download the Tech Brief on Laser Ablation Here.