The Research Of The Electroless Plating On The Soft Microspheres Applied In The ACA

Anisotropic conductive adhesive (ACA) is an advanced packaging material with lots of merits, but its manufacture is of high tech upon multiple branches of knowledge. This thesis was organized by the clue of preparation of the metal-coated microspheres applyed in anisotropic conductive adhesive (ACA) and all the experimentations were focused on the electroless plating of conductive micro-spheres for ACA. After the introduction of the basic knowledge and current development of ACF in electronic package, the key technologies of conductive micro-spheres for anisotropic conductive adhesive (ACA) were developed, and the technologies were the nickel coating on the micro-spheres.In this thesis, a step of preparing the conductive particles of ACA was investigated, that is, electroless nickel plating on polymer microshperes. The process of the coating formation consists of four steps: chemical etching, sensitization, activation, and electroless plating. After a mount of experiments we change reaction time, control the rate of reaction, improve the preceding treatment, finally get the optimized process: 0.23μm in thickness uniform and smooth Ni-P coating on 3.7μm in diameter polystyrene microspheres was formed upon 25 min plating. The advantage of this plating process is to ensure an easy and accurate control on the thickness and the quality of the plating coat.The preparation of nickel-coated microsphere is ready for the further gold plating and the manufacture of ACA.