High frequency circuit board refers to a special type of circuit board with high electromagnetic frequency, used for PCBs in the fields of high frequency (frequency greater than 300MHz or wavelength less than 1 meter) and microwave (frequency greater than 3GHz or wavelength less than 0.1 meter). It is a circuit board produced using ordinary rigid circuit board manufacturing methods or special processing methods on microwave substrate copper clad board. Generally speaking, high-frequency boards can be defined as circuit boards with frequencies above 1GHz.

　　High frequency circuit boards are one of the high difficulty boards, so what are the requirements for making high frequency circuit boards?

　　1、 Drilling

　　1. The drilling feed speed should be slow, with a speed of 180/S. A new drilling nozzle should be used, with aluminum plates placed on top and bottom. It is best to drill with a single PNL, and the hole should not be exposed to water;

　　2. The ground plate copper sinking circuit is made like a normal double-sided board;

　　3. Special attention: High frequency circuit boards do not require the removal of adhesive residue.

　　2、 Anti welding

　　1. If green oil needs to be printed on the substrate of high-frequency circuit boards, green oil should be printed twice (to prevent foaming of green oil on the substrate); Do not grind the plate before etching and removing tin, only air dry it.

　　2. If a high-frequency circuit board requires green oil backing, it is not allowed to grind the board before soldering, and a red seal should be stamped in the MI.

　　3. If green oil needs to be printed on some substrates of high-frequency circuit boards and green oil is not printed on some substrates, a "base film" needs to be produced. The base film only retains the green oil on the substrate, and the second normal production can be carried out after the base baking board.

　　3、 Tin spraying

　　Before spraying tin, it is necessary to bake 150 degrees for 30 minutes before spraying tin.