A processing method for alleviating Galvanic corrosion of PCB board
A PCB board and processing method technology, which is applied in the field of Giavanni corrosion effect processing, can solve the problems of small pads, loss, and difficult inspection, etc., and achieve the effects of improving yield, reducing corrosion degree, and simple operation
Inactive Publication Date: 2008-09-17
ZTE CORP
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Problems solved by technology
At present, for PCB boards with a ratio of ENIG area to OSP area greater than 200, PCB manufacturers can only reduce the impact of the Giavani effect on the pad by controlling the pH value of the potion and increasing compensation, but the pad becomes smaller. Even the falling off situation still exists. If the problem is not checked out at this time, the electrical test cannot be done after the OSP treatment (the OSP film is not conductive), so the open circuit caused by the Galvanic corrosion effect in the PCB processing plant will flow. When it comes to the customer, it is difficult to check this problem, and it will cause relatively large losses if the problem is found after the welding is completed
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[0017] see figure 2 , the core idea of the present invention is: after the design of the schematic diagram of the PCB board is completed, analyze and find the network where the Giavanni corrosion effect will occur, and then add the devices that have been processed by OSP on the schematic diagram and place them on the OSP during layout. layer, or add a copper sheet that has been treated with OSP to each of these networks when the PCB board is drawn, so that the area ratio of the ENIG disk and the OSP disk in these networks is less than 200.
[0018] The present invention will be further described below in conjunction with accompanying drawing and specific embodiment:
[0019] by figure 1 As an example, the figure shows a typical keyboard network connection diagram, the keyboard adopts ENIG process, and is connected to the main chip, and the main chip adopts OSP process.
[0020] This keyboard network is connected to 5 keyboard outer ring pads, according to the data in the ...
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The invention discloses a processing method for reducing a galvanic corrosion degree of a PCB board, comprising: analyzing and finding a network in which a galvanic corrosion effect is generated after designing a PCB board principle figure, and then increasing the area of an organic coating process OSP disk in the network. Because when the area proportion of an ENIG disk and the OSP disk in the same network is larger than 200, the galvanic corrosion effect is easy to generate, the invention uses a method of adding an OSP-processed device or an OSP-processed copper sheet in the network in which the galvanic corrosion effect is easy to generate so as to increase the area of the OSP disk, thereby effectively reducing the galvanic corrosion degree, improving the PCB yield, having simple operation without effecting other portions of the produced PCB.
Description
technical field [0001] The invention relates to the technical field of PCB (Printed Circuit Board, printed circuit board) design and manufacture, and in particular to a treatment technology for the Giavanni corrosion effect of a selective immersion gold board. Background technique [0002] At present, two surface treatment methods are generally used for mobile phone PCB boards, namely ENIG (ENIG) and organic coating process (Organic Solderability Preservative, OSP). Generally, mobile phone PCB boards will adopt the method of ENIG+OSP. Generally, the surface treatment of mobile phone boards that do not contain BGA (Ball Grid Array, ball grid array structure) and CSP (Chip Scale Package, chip-level packaging) devices adopts the ENIG process, such as mobile phone key boards; Selective immersion gold (ENIG+OSP) is used for mobile phone PCB boards with complex pitch devices. [0003] ENIG is chemical (electroless) nickel-gold, while OSP is an organic coating process. For select...
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IPC IPC(8): H05K3/00
Inventor 韩科许路
Owner ZTE CORP