Pre-windowing process of high-density interconnected PCB (printed circuit board) with buried blind hole

Abstract

The invention relates to a pre-windowing process of a high-density interconnected PCB (printed circuit board) with a buried blind hole. The pre-windowing process comprises the steps of: (1) coating a positive photoresist film layer on the upper surface of a lateral ply to be processed; (2) placing an aluminum sheet with a through hole on the upper surface of the lateral ply coated with the positive photoresist film and then placing the lateral ply and the aluminum sheet into an exposure machine to expose; (3) taking out the aluminum sheet after exposure and performing development for the lateral ply; (4) etching the developed lateral ply; (5) stripping film to peel off the residual positive photoresist film on the lateral ply; (6) cleaning the lateral ply; (7) drying the lateral ply; (8) drilling a blind hole in the lateral ply by laser; and (9) electroplating the blind hole to form a conductive hole and then performing subsequent processing such as pattern transfer and the like. According to the pre-windowing process of the high density interconnected PCB with the buried blind hole provided by the invention, the processing difficulty is reduced, the processing precision is improved, the work efficiency is enhanced, the production cost is lowered, and the yield of the product is increased.

Description

technical field [0001] The invention relates to a pre-opening process of a PCB board, in particular to a pre-opening process of a high-density interconnected PCB board with buried blind holes. Background technique [0002] With the rapid development of the PCB board industry, the traditional PCB board drilling is affected by the drill tool. When the drilling diameter reaches 0.15mm, the production cost is already very high, and it is difficult to improve again, which limits the development of PCB boards. . With the continuous advancement of technology, there has been a high-density interconnect board, which is the HDI board. It uses laser for drilling, the aperture is generally 0.075-0.15mm, and the processing cost is also reduced. The line width is generally 0.075-0.1mm, the size of the pad can be greatly reduced, and more per unit area can be obtained. Line distribution. This kind of HDI board adapts to and promotes the further development of the PCB board industry. ...

AI Technical Summary

Problems solved by technology

[0005] 1. The polyethylene terephthalate PET material has the phenomenon of expansion and contraction with the change of temperature and humidity, especially the change of humidity. Secondly, the PET film will undergo irreversible physical deformation during the process of production, transportation, storage and use, resulting in Misalignment of the laser window with the bonding disc on the inner layer, resulting in multiple quality defects

[0006] 2. The thickness of PET film and protective film is usually 200 microns, and the thickness of negative photosensitive dry film is 30-50 microns (the thickness of negative photosensitive ink is 10-20 microns). The influence of the protective film and the repeated diffraction of light, as well as the influence of the poor resolution when the thickness of the photoresist layer is large, the window opening diameter is prone to be small or even disappear, resulting in defective products and low product yield.