Internal stress and adhesion of amorphous Ni-Cu-P alloy on aluminum

This study investigated the effect of saccharin on the internal stress and the adhesion of amorphous Ni-Cu-P deposited on aluminum. An amorphous Ni-Cu -P deposit with slight compressive stress can be produced when one adds 8-1 0 g/l saccharin into the Ni-Cu-P deposition solution. The stress relief mec hanism was investigated. The addition of saccharin restrains the coalescenc e of the islands within Ni-Cu-P nodules and reverses the internal stress of the electroless Ni-Cu-P deposit from tensile to compressive. The adhesion strength of the Si/Ti/Al/ Ni-Cu-P multilayer specimen obtained with 10 gn s accharin is around 35 to 45 MPa, and the fracture occurs at the silicon sub strate after the pull test. The shear strength of the Ti/Al/Ni-Cu-P bump (1 00 x 100 mu m) on Si is 132.9 +/- 12.7 g, and the fracture occurs at the Ni -Cu-P deposit after the shear test. Moreover, the inhibition of coalescence of the fine islands within Ni-Cu-P nodules increases the brightness and th e hardness of the deposit. (C) 2000 Elsevier Science S.A. All rights reserv ed.