One, why should use gold plating board
With the integration of IC is getting higher and higher, the more and more IC feet are more and more dense. And vertical tin spray process is difficult to will become thin pads blowing flat, which gives the SMT mount brought difficulty; also HASL inactive life (Shef life) very short. And gold plate just to solve these problems: 1 for surface mount technology, especially for 0603, 0402 subminiature surface mount, because the pad evenness is directly related to the solder paste printing process quality, on the back of the reflow soldering quality play a decisive impact. So, the whole plate gold in high density and ultra small table paste process often seen. 2 in the trial stage, influenced by the components procurement, and other factors often not board to the welding immediately, but often etc. several weeks or even months before use, gold plate stand-by life (shelf life) than Pewter many times longer so we are willing to adopt. Besides in the stage of PCB GOLD PLATED PEWTER plate compared with not much difference between the cost and the.
But with more and more dense wiring, line width, spacing has reached 3-4MIL. So bring a wire short circuit problem: with the frequency of the signal becomes higher and higher, the trend skin effect caused by signal in multi layer transmission of signal quality, the more obvious the effect: skin effect is: high frequency alternating current, the current will tend to be concentrated in the wire surface flow. According to the calculation, skin depth and frequency of the relevant: the other shortcomings of gold plate in the gold plate and gold plate in the difference between the table is listed.
Two, why should use heavy gold plate
In order to solve the above problems, the gold plate of PCB mainly has the following characteristics:
1, due to heavy gold and gold plated crystal structure is not the same, heavy gold will be more yellow than gold, more satisfied with the customer.
2, due to heavy gold and gold plated crystal structure is not the same, more easily than gold plating, it is more easy to welding, will not cause poor welding, causing customer complaints.
3, due to heavy gold plate only on the welding plate nickel gold, skin effect in the signal transmission is in the copper layer will not affect the signal.
4, due to heavy gold plating, the crystal structure is more dense, not easy to produce into oxidation.
5, due to heavy gold plate only nickel gold plating on the plate, it will not produce gold wire caused by a short.
6, due to heavy gold plate only on the welding plate nickel gold, so the resistance welding on the line and the combination of copper layer is more solid.
7, the project will not affect the distance when making compensation.
8, due to heavy gold and gold plated crystal structure is not the same, the stress of the gold plate is more easy to control, the state of the product is concerned, it is more conducive to the processing of bonding. At the same time also because of Shen Jin than gold, so heavy gold plate do not wear gold fingers.
9, gold plate smooth and for life and is as good as gold plate.