| 摘要 |
PURPOSE:To obtain a substrate with a bump, which can be bonded to the Al pad of an IC chip stably, by expanding and increasing the roughness of the surface of the bump by plating. CONSTITUTION:A conductor pattern 3 comprising a copper foil is bonded to a substrate 1 with a bonding material 2. Thereafter, Ni 8 and Au 9 are applied on the copper foil 6 by electroplating. Then a current is concentrated to a protruding parts 7. Therefore the protruding parts 7 become thick, and the peripheral parts become thin. Thus the roughness of the surface of a bump 5 is increased. When plating is performed for a short time in the vicinity of the upper limit of allowable current density, the large roughness is obtained. Especially when the surface roughness is made to be 5-20 mum, the oxide film of an Al pad can be readily broken when bonding to the Al pad of an IC chip is performed, and the bonding strength and the stability are remarkably increased. |
