ELECTRONICS
Laser processing is helping enable an emerging generation of displays made from microLEDs for products such as watches and augmented reality headsets g
(UV) lasers can be used. This process involves ablating the PCB material layer by layer until separation occurs. CO2
over mechanical milling and sawing processes that they are non-contact, but they do generate a sizeable heat- affected zone (HAZ). Although slower than CO2
lasers have the advantage lasers, using UV-
based diode-pumped solid-state (DPSS) lasers instead reduces the size of the HAZ and creates substantially less debris. Keeping this type of
processing contact-free reduces costs because there is little wear and tear on the material being ablated or on the cutting technology. The accuracy of laser cutting also reduces material wastage, and enables panels to be fitted together readily during assembly stages.
Marking for traceability The PCBs that all electronics are built around are just one of the components of electronic equipment that must be marked for traceability and quality control. This is so that if an error is identified during a production process, the batch of PCBs that the faulty board comes from can be readily found. These marks can consist of
bar codes, data matrix codes, serial numbers or text. Lasers are ideal for this task since the marks must fit into a tiny space and be applied on materials that are sensitive to force and heat. In some cases, such as in
“Electronic connectors can be laser-marked, as can the flame-retardant plastics used for some electronic components, including switches”
aerospace applications, the marks will be subject to harsh environmental conditions, so using laser marking as opposed to marking with inks is preferential because it is less likely to erode or fade over time. Laser marking is also a very quick process, which speeds up production by enabling large quantities of parts to be marked in a short timeframe. Lasers with wavelengths in the
infrared, UV and green regions of the spectrum can all be used for marking wafers, while minimising the amount of surface damage to the wafer. Such damage is undesirable as it could subsequently act as a dust trap. Because semiconductor
materials used in electronic hardware must be marked with a machine-readable code, the precision and speed of pulsed lasers makes them the perfect choice for this task in which the surrounding material must be protected. The pulsed lasers used for marking create a change in the
18 LASER SYSTEMS EUROPE THE 2023 GUIDE TO LASER SYSTEMS
surface of the material they are focussed on without causing excess heat input, which is what also makes them particularly suited to creating visible marks. The type of surface change is dependent on not only the pulse duration but also the wavelength of the laser and the irradiance of the beam. Electronic connectors can
also be laser-marked, as can the flame-retardant plastics used for some electronic components including switches. Flame- retardant plastics need to be marked for traceability and this can be carried out effectively using UV lasers, because their wavelength is absorbed well by these materials. The laser induces a photochemical reaction on the surface of the component, which creates the mark.
Marking is also useful for
assembling electronic parts as well as for their testing and ongoing maintenance, so the fact that lasers are suitable for marking ceramics, metals and plastics makes them ideal for widespread use in the electronics industry.
Looking to the future With chips continually shrinking, and an ever increasing demand for more consumer electronics products, the need for lasers within the electronics sector is set to grow. As PCBs get smaller for
example, the holes in them will also need to reduce in size – the
creation of which is a task that can only be accomplished by laser drilling. Lasers are also increasingly being used in the production of displays for devices such as smartphones and tablets. Laser scribing, for instance, can be used in the manufacturing of blue LEDs, as well as for photovoltaic cells for solar panels.
In the meantime, laser
processing is helping enable an emerging generation of displays made from microLEDs for products such as watches, TVs and augmented reality (AR) headsets.
During manufacturing, the
microLEDs – which at only a few micrometres thick are around a hundred times smaller than standard LEDs – require releasing from the wafer that they are grown on. So far, the precision and
energies of deep UV (DUV) excimer lasers are proving to be perfect for this task. l
REFERENCES [1]
https://www.statista.com/outlook/cmo/ consumer-electronics/worldwide
For more information about the application of laser technology in the electronics industry, visit:
www.lasersystemseurope.com/ industries/electronics-displays
@LASERSYSTEMSMAG |
WWW.LASERSYSTEMSEUROPE.COM
Smartwatch: Ground Picture
AR headset: khoamartin
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