| 摘要 |
PURPOSE:To obtain the titled lead frame of high reliability excellent economically by a method wherein the bonding parts of the leads frame are coated with necessary micro spots. CONSTITUTION:At least a kind of Au, Ag, Pd, Ni, Cu, Al or alloys of these such as Au-Ag, Ag-Pd, Pd-Ni, Al-Ni, Cu-Ni, Al-Si, Ag-In, Ag-Zn and Cu-Ag is put on the wire bonding parts of inner leads in spot form and then irradiated with laser beams into a fusion coat. From the view-point of workability, it is preferable that a fine-powder paste is dripped or injected and screen-printed to this metal. In other words, a fine powder 0.01-0.1mum in grain size produced by vapor phase reaction is the best. A high-output type such as YAG or CO2 laser is used for the laser light source. This is made to scan by condensation to a size corresponding to the metal-coated part or to about 0.1mm.phi. Since this light source yields an energy density of 10<4>-10<8>W/cm<2>, spot coating can be accomplished by fusion and quench in a short time of 1-10<-10>sec. |
