RFH nanosecond laser processing PCB board blind holes

PCB board, known as printed circuit board in Chinese, is the support of electronic components and the carrier for interconnection of various components. It has the advantages of high density, high reliability, and designability. Toys, as large as computers and large equipment, as long as integrated circuits are involved, they are inseparable from the blessing of PCB boards.

With the development of diversified functions of electronic equipment, the requirements for PCB boards are getting higher and higher, and high-density circuits, multi-layer boards, and miniaturization have become the mainstream trends. Studies have shown that one of the effective ways to increase the wiring density of the printed board is to reduce the number of through holes and increase the number of blind holes.

Blind via refers to a via hole that connects the surface layer and the inner layer without penetrating the entire board. It is located on the top and bottom surfaces of the printed circuit board and has a certain depth. It is used for the connection between the surface layer and the underlying inner layer. The depth of the hole Do not exceed a certain ratio (aperture ratio). Blind vias are generally used in PCB boards with four or more layers.

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The key point of the blind hole process is that special attention should be paid to the depth of the drill hole, which will affect the use of the circuit board at light, and cause the circuit board to be directly scrapped in severe cases. At present, the industry adopts multi-layer bonding method, mechanical drilling and laser drilling for blind hole processing. The multi-layer bonding method drills the ion layers that need to be connected in advance according to the designed circuit diagram, and then glues them. This method especially tests the positioning accuracy of the bonding equipment; mechanical drilling is easy to cause cracks inside the PCB, and Inability to process small blind holes in large quantities.

Therefore, laser drilling is widely used in the industry to process blind holes. Laser drilling uses the characteristics of high energy density beams and high collimation of lasers to guide the focused beams to the processing position by matching optical devices. The high concentration in time and space makes the material in the active area melt or vaporize instantaneously, and then evaporate to form blind holes with a certain ratio of diameter to depth.

The industrial-grade nanosecond laser developed and designed by RFH can meet this process requirement well and quickly. The 355nm UV laser it outputs has a narrow pulse width of less than 25ns, which has natural advantages in blind hole processing. First, the wavelength is short, the material absorptivity is high, and with the narrow pulse width, the heat-affected zone is very small during processing; second, the superior beam quality (M2 < 1.2), the spot diameter after focusing is small, and it is easy to obtain fine micro-blind holes ; Third, the repetition frequency is from single pulse to 500kHz, and the processing efficiency is higher, which can meet the high-speed automatic production, and the unique resonant cavity design, equipped with a high-precision cooling system, is very suitable for the 7*24-hour industrial operating environment. The integration of these advantages, the high precision of the processed blind holes, can solve the hole position deviation of the blind holes, shorten the process, effectively improve the processing efficiency, reduce the production cost, and is more suitable for the needs of mass production of PCB blind holes.