Study On Silver Plating With DBC Substrate Connected Chip By Nano-silver Paste

For the electronic device packaging, semiconductor device interconnection to the substrate is an important part because the substrate provides necessary electrical conduction or isolation, structural support, and heat dissipation. Currently, the typical technology of semiconductor device interconnection is connecting the terminal of a semiconductor device and the substrate by solders or conductive adhesives, and the other terminal connected with fine aluminum or gold wires. Nano scale silver pastes as lead-free solders can sinter at low temperature, realize high power, high temperature electronic device of connection and encapsulating techniques. The solderability of DBC substrate for die-attachment by using micro silver pastes is poor, and the copper is easily oxidated at high temperature. So plating silver on the copper surface can improve the performance.The traditional silver bath almost all contain cyanide, using cyanide solution can get good appearance, good adhesion and meticulous crystallization silver layer, but cyanide is virulent, seriously threaten the ecological environment. This paper researches on plating silver by the non-cyanide technology in the surface of copper. First of all, plating silver by using sulfite, and analyzing the performance of the silver layer; second, plating silver by using thiosulfate, and analyzing the performance of the silver layer; finally, plating silver by magnetron sputtering, and analyzing the performance of the silver layer.It is found that the bonding force between silver layer and copper substrate is good by using sulfite, but the color resistant of the silver layer in high temperature is poor; the bonding force between silver layer and copper substrate is poor by using thiosulfate, but the silver layer is dense; based on the nickel layer, the bonding force and color resistant of the silver layer by magnetron sputtering is perfect, thus ensure the connection strength of the nano scale silver pastes connecting the semiconductor devices and DBC substrate.