Process and advantages of PCB laser drilling
The 21st century is a period of rapid development of electronic technology. More and more integrated circuits are widely used, making printed circuit boards more and more multi-layered and multifunctional. At the same time, fast turnkey is one of the competitive advantages of PCB manufacturers, such as Rapid PCB assembly, PCB prototyping, etc. Traditional mechanical drilling methods can no longer meet the demand, and new laser drilling technologies have developed rapidly in this environment.
Principle of laser drilling
Laser is a powerful beam of light that is excited when the “ray” is stimulated by external sources and increases in energy. Infrared and visible light have thermal energy, and ultraviolet light has optical energy. When this type of light hits the surface of the workpiece, three phenomena occur, namely reflection, absorption and penetration.
The laser spot struck on the substrate through the optical component has multiple modes of composition, and three reactions will occur with the illuminated spot.
The main function of laser drilling is to quickly remove the substrate material to be processed, and it mainly relies on photothermal ablation and photochemical ablation, or excision.
(1) Photochemical ablation: refers to the effect of high photon energy (over 2eV electron volts) in the ultraviolet region and high energy photons with a laser wavelength exceeding 400 nanometers. This high-energy photon can destroy the long molecular chains of organic materials and become smaller particles, and its energy is greater than the original molecules, and try their best to escape from them. Under the condition of external force, the substrate material is quickly removed. Form micropores. Therefore, all types of process methods do not contain thermal burning, and carbonization will not occur. Therefore, cleaning up before cavitation is very simple.
(2) Photothermal ablation: refers to the pore-forming principle in which the processed material absorbs high-energy laser and is heated to melt and evaporate in a very short time. In this process, under the effect of high energy on the substrate material, there is burnt carbonization residue on the formed hole wall, which must be cleaned before pore formation.
The above is the basic principle of laser drilling. At present, there are two most commonly used laser drilling methods: The lasers used for drilling printed circuit boards mainly include RF excited CO2 gas lasers and UV solid-state Nd: YAG lasers.
Advantages of laser drilling
Laser drilling has just come out, PCB manufacturers quickly realized its huge advantages, and laser drilling machines have been widely used in the processing of interlayer through holes. The PCB material is a variety of materials, including copper foil for forming electronic circuits, resin for ensuring electrical insulation, and glass fiber composites for enhancing mechanical strength. There are many industries that need to use laser drilling machines, such as electrical, semiconductor, aerospace, medical and automotive industries.
What are his advantages?
1. It is non-contact type to ensure minimum material deformation.
2. Highly accurate and consistent results can be achieved.
3. Provide customers with complete control.
4. A laser drilling machine can perform multiple functions and process multiple materials to improve production efficiency.
5. Produce small diameter holes with high aspect ratio.
6. Compatible with many different industries and applications.
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