The novel type of conductive paste using functionally gradient Ag-Cu powder

The novel type of conductive paste has been developed and the application of it has been investigated. In this paper, two types of conductive paste are introduced. One is Polymer thick film type, which should be cured at 150-220 degrees C. The other is Cermet thick film type, which should be fired at 600 degrees C or 900 degrees C. The applications of them are printed circuit pattern, EMI shield, conductive layers for soldering, electrode, hybrid integrated circuit, and so on. On these types of pastes, the specific structure of Ag-Cu alloy powder has an important role for the excellent performances. Ag component is highly concentrated on the surface and its concentration gradually decreases from the surface into the inner part. This unique structure has made it possible to realize an excellent durability (especially oxidation resistance), sufficient adhesion strength, and least ionmigration comparable to existing Cu paste. In addition, the distribution of the powder size is suitable for the conductive paste. In using as the PTF paste, high electroconductivity comparable to Ag has been obtained. And in using as the CTF paste, the excellent sintering property at comparatively low temperature has been exhibited. In this paper, at first, the unique characteristics of Ag-Cu powder will be. shown and some examples of application will be described.