The manufacturing method of high-frequency microwave ultra-long circuit flex board
In the industry, the circuit board with a length of more than 1000mm is called ultra long circuit board. Due to the flexness of PTFE, the inner dielectric material of high-frequency circuit board, the flex PCB board with a thickness of less than 0.5mm is easy to deform due to its flex and thin substrate, strong internal stress and tension, The tension of copper foil is not consistent with the internal stress and the base material of the high-frequency PCB, which is far less than the base material, forcing the internal stress and tension of the base material to be unable to release, and the base material is temporarily in a stable state. After the etching and grinding process, most of the copper foil layer on the plate surface disappears, leaving only the effective line copper foil, and the internal stress of the copper foil disappears. At this time, the internal stress of the base material is released, and the tension expands, resulting in the deformation of the plate.
This paper introduces a method of making a high-frequency microwave ultra-long circuit flex board:
According to the size requirements, the automatic cutting shears are used to cut the boards to produce the flex boards with a length of more than 1000mm and the thickness of less than 0.5mm;
The flex circuit board was cleaned with 3-6% H2SO4 solution, and the grinding section was brushed with 8-16% silicate solution; First, wet film the circuit flex board after grinding for the first time, then light painting, exposure, development, check after development, then etch and cool; Wet the thick circuit board for the second time, then light painting, exposure, development, check after development, then etching, and finally cooling; Drilling, grinding, coating anti-oxidation film, edge milling, finished product inspection and packaging are used to get the finished product.
The high frequency microwave ultra-long circuit flex board produced by the invention has the advantages of low production cost, good reliability, excellent dimensional stability, non-deformation of board surface aperture and figure, and one-time improvement of product qualification rate.