In this paper, single-sided aluminum plate PTFE key processes processing process and process control points.
Metal-based PCB PCB as a category, the 20th century by the United States first 60 years, with cooling due to its good thermal expansion of small, size, high stability and good shielding characteristics, is widely used in high frequency receiver machines, high-power module power supply, electronics and telecom products. I shall be the largest single unit of application of Al-based PTFE board (hereinafter referred to as Al substrate).
2, Al substrate processing difficulties
As the Al substrate in the electrical properties of the special requirements of the dual characteristics of metal Al and the Al substrate thickness of the thick (3-10mm) 等均 difficulties caused by the following process.
2.1 lines with high precision: the value of engineering required by the dimension of accumulated experience to judge.
2.2 etching: etch width must meet the requirements of the drawings, to achieve no residual copper and smooth lines.
2.3 Machining: Request processed Al substrate without delamination, and drilling burr-free, neat appearance required edge.
2.4 Al substrate surface does not allow any scratches, black, color and so on.
3, the production process:
4, elements of process control
4.1 making the film: the existence of the side corrosion, drawing lines, they must wait for the precision, so the film must be in the light painting technique to make some compensation, process compensation value must be based on the thickness of Cu measured with different values to determine the side corrosion. Film was negative.
4.2 in materials: as far as possible procurement fixed size 300 × 300mm and the Al surface and the Cu surface protection film of the plate are, in particular better than Rogers. The same dielectric constant and the drawings.
4.3 System graphics:
4.3.1 of this process before the deal due to take on the Al-based protection, many ways, it is recommended to use 0.3mm thick epoxy board, with the Al substrate the same size, closed with tape around, compaction, to prevent infiltration solution .
4.3.2 on the Cu surface treatment of the proposed chemical micro etching treatment, the best.
4.3.3 Cu surface treatment is completed, drying the wet film immediately after printing to oxidation.
4.3.4 develop, the use of a magnifying glass scale measuring whether the drawing line width and space requirements, to ensure smooth and no jagged lines. If the Al substrate thickness greater than 4mm, proposed to develop the plane rolls and removed to prevent the card board lead to rework.
4.4 Etching: The Department of CuCl-HCl acid solution corrosion. Adjust the solution with the experiment, the best time in the corrosion of Al etching the substrate, the graphic face down to reduce the amount of lateral erosion.
4.5 Surface treatment (dip Sn): etching process is complete, do not rush back film, immediately ready to dip Sn solution, the back film, which dipped Sn, the best.
4.6 Machining: contour machining, CNC milling machine to be used will be separated from PTFE and Al-based processing, this would avoid both heat and deformation caused by the stratification of different, but also the graphic face on, in order to reduce stratification and burr generation.
Al substrate processing, we should focus on Al-based protection and precision control of line graphics, good control in the production process elements of each process can be processed consistent with the technical requirements of the qualified product drawings.