多层印制线路板沉金工艺控制简述（Brief introduction to process control of multilayer printed circuit board）.docVIP

多层印制线路板沉金工艺控制简述（Brief introduction to process control of multilayer printed circuit board） Brief introduction to process control of multilayer printed circuit board I. brief introduction of process The purpose of the gold deposition process is to deposit nickel coating on the printed circuit surface with stable color, good brightness, good coating and good weldability. Basically can be divided into four stages: pretreatment (degreasing, micro corrosion, activation, after immersion), sink nickel, sink gold, after treatment (waste gold, water, DI washing, drying). Two. Pretreatment Gold pretreatment usually has the following steps: oil removal (30%AD-482), micro corrosion (60g/InaPS, 2%H2SO4), activation (10%Act-354-2), and post leaching (1%H2S04). In order to remove the copper surface oxide, and sink the palladium in the copper surface to be used as the precipitating nickel activation center. One of these processes is not good, which will affect the subsequent deposition of nickel and gold, and lead to the rejection of bulk properties. In the production process, all kinds of potions must be regularly analyzed and supplemented, controlled within the required range. For example, the more important: Micro etch rate should be controlled in the 25U 40U, the activation of copper content is more than 800PPM drops must open new cylinder, affect the quality of cleaning and maintenance of PCB potion cylinder of the antithetical couplet is large, in addition to microetch cylinder, cylinder, cylinder should be dipped after every week for each cylinder, cylinder should also be washed every week. Cleaning. Three, sink nickel The main component of electroless nickel drops to Ni2+ (5.1-5.8g/1) and reducing agent sodium hypophosphite (25-30g/1) and a stabilizer for more stringent requirements due to chemical nickel syrup composition range, each class must test two times in the production process, and according to the production of plate area of bare copper or experience adding reduci