Lead Free Assembly: Novel Electrically Conductive Adhesives Compatbile with 100% Sn Metallisations (Chinese-Translated)

ABSTRACT Electrically conductive adhesives are an alternative to traditional solders used in the electronics industry. They provide an environmentally friendly alternative to conventional Sn/Pb metal solders offering additional attractive technical advantages including low temperature processing, fine pitch capability and better resistance to thermal cycling. Traditionally electrically conductive adhesives have been used in hybrid applications. These applications typically use noble metallisations such as gold and silver palladium on ceramic substrates. The major limitation of electrically conductive adhesives has been their instability on common electronic metals such as copper and Sn/Pb solder. Recently, electrically conductive adhesives have been re-evaluated in applications that were traditionally reserved for solders. The reason for this renewed interest can be attributed to the development of adhesives with stable contact resistance in combination with non-noble metals including OSP copper, Sn/Pb alloys and even 100% Sn. The stable contact resistance on Sn surfaces is very promising as it has been well documented that high Sn alloys will most certainly be widely used by the electronics and component industry in the future. This paper shows compatibility data between the new developed electrically conductive adhesives and surface mount components with 100% Sn metallisations. Different types of components from different suppliers all containing 100% Sn terminations have been evaluated.