1) Double-head ultraviolet drilling system;

　　2) Double-head CO2 laser drilling system;

　　3) Hybrid laser drilling system (CO2 and UV).

　　Such drilling systems in all HDI PCB board fabrication processes have their own advantages and disadvantages. Laser drilling systems can be simply divided into two types, two-bit single-wavelength systems and two-bit dual-wavelength systems. Regardless of the type, there are two main components that affect the ability to drill:

　　1) Laser energy/pulse energy;

　　2) Beam positioning system.

　　The energy of the laser pulse and the transmission efficiency of the beam determine the drilling time, which refers to the time for the laser drilling machine to drill a micro-through hole, and the beam positioning system determines the speed of movement between the two holes. These factors together determine the laser drilling mechanism for the given requirements of the micro-hole speed. The dual-head UV laser system is best suited for drilling holes smaller than 90μm in integrated circuits and has a high aspect ratio.

　　The dual-head CO2 laser system uses Q-switched RF excited CO2 lasers. The main advantages of this system are high repeatability (up to 100kHz), short drilling time, wide operating surface, and only a few shots can be fired to drill a blind hole, but its drilling quality will be low.