Electroless and immersion plating process towards structures and IMC formation

Abstract

The selection of surface finish on printed circuit board is very important in soldering process because it can prevent the copper from oxidation and provide solderable surface. It is also will influence the cost, manufacturing, shelf life, surface quality, final product reliability and environment.Electroless and immersion plating process has now become an important and popular surface finish in electronic industry due to simple and low cost process. The application of electroless plating are widely used in electronic industry, however it also was used in various industries such as aerospace, automotive, oil and gas, chemical processing where the need on the complex shape, homogeneous and uniform layer are required. Besides, every surface finish has their strength and weakness. Immersion silver is one of the surface finishes frequently used on the printed circuit board due to their characteristics such as good solderability and wettability, easy assembly and low cost. Both of these two processes were acts as barrier layer between copper substrate and solder balls. This review was discussed about electroless nickel and immersion silver plated on copper substrate, coating process and parameters involved. The topic also covered include the morphology and thickness of the intermetallics formed during soldering as well as the isothermal aging process.