| Multilayer chip inductor (MLCI) is one of the three major surface assembly of themost important passive component in the circuit. With the development of electronicequipment is miniaturization, lightweight, high performance, high density of SurfaceMount Technology (SMT) has been paid more and more attention. Multilayer chipinductor tin plating performance directly affects the reliability of mount. Manufacturingtechnology of multilayer chip inductors include burdening,milling, printing, lamination,cutting, dumping, sintering,chamfering, coating silver, plating, testing and sorting andother process, The tin plating process of multilayer chip inductors and treatment afterplating technology is studied in this paper. With the increasing requirements of thecomponents, the plating solution, in addition to affect component terminal, leadsolderability, compactness, matrix composite materials on the electronic componentsalso can have adverse effects, especially the mass production and the use of a small chipresistor, multilayer chip inductor, the original widely used in acid, alkaline platingsolution for special glass (high lead glass) dissolution and corrosion package, highactivity of ceramic materials for the chip resistor and multilayer chip ceramic capacitoris very obvious, greatly affected the quality of components. At the same time, this kindof plating liquid corrosion to the equipment, It is difficult to solve the problem ofoperating personnel health hazards, sewage discharge and lead pollution to environment.Therefore, an environment-friendly electroplating process:(1) the pH value of platingsolution near neutral, vulnerable to acid, alkali corrosion material, does not affect itsperformance;(2) Non-toxic, good operating environment;(3) The plating part ofcomponent have fine crystal, silver white appearance, excellent solderability andresistance welding of coating,(4) Convenient operation and maintenance, stable andreliable quality, Easy treatment of waste water to plating process, is of great economicand social value.Tin and tin-lead alloy coating has excellent corrosion resistance and weldabilityhas been widely applied in electronic industry. But in recent years, due to the world ofthe request of environmental protection is more and more strict, the use of lead islimited, the EU launched ROHS instruction, the electronic components industry, the component pin to plating weldability of pure tin development. Before the tin platingsolution is using phenol sulfonate salt, halide and fluoborate based, this kind of solutionconcentration range is narrow, control of the production process more difficult, bathtoxic and difficult to deal with. Methyl sulfonate bath system, plating solution is neutral,coating of low stress, good weldability, high metal ion content allowed, suitable for highspeed electroplating bath, and a wide range of production control, convenientmaintenance, bath more environmentally friendly easy to handle, and has very highindustrial application value.The detailed research contents are as follows:In this work, through the orthogonal test of methyl sulfonate tin-plating processoptimum formula and properties of the bath, and Compared with sulfate tin platingperformance.Tests were conducted on oxidation resistance of tin plating products after treatment,comparison of different after treatment methods, effects on the antioxidant ability of theproducts.Take A (stannous methanesulfonate), B (methyl sulfonic acid), C (additive) and D(current density) of four factors, each factor three levels, four factors and three levelsorthogonal experiment, using L9(34) orthogonal table. Test operate at room temperature,time is60min, the porosity as the results of orthogonal test analysis. The optimalformula is obtained through the test process.Through experiments using different antioxidant treatment methods, evaluate itsweldability, obtained the best antioxidant processing method after tin plating. |
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