Semiconductor device and its mfg. method

接合焊盘和金线的球部分之间的粘附力得以改善以提高半导体器件的可靠性。约1wt.％的Pd含在金线中，金线用于连接形成在布线基板上的电极焊盘和形成在半导体芯片上的电极焊盘(主要由Al形成的顶层布线的露出区域)，由此，在形成在半导体芯片上的电极焊盘和金线的球部分之间的接合部分中，抑制了Au和Al的相互扩散，以防止PCT(压力锅蒸煮试验)之后形成Au#-[4]Al。由于防止了易于被腐蚀的Au#-[4]Al的形成，即使形成在半导体芯片上的电极焊盘的间距小于65μm并且每个金线的球部分的直径小于55μm或每个金线的线部分的直径不大于25μm的情况中，也可以得到需要的金线接合强度。同样在顶层布线很厚或者很薄或者接合温度很低的情况中也可以确保需要的接合强度。 A semiconductor device with improved the adhesion between bonding pads and ball portions of gold wires is provided to improve the reliability of a semiconductor device. About 1 wt. % of Pd is contained in gold wires for connection between electrode pads formed on a wiring substrate and electrode pads (exposed areas of a top layer wiring formed mainly of Al) formed on a semiconductor chip. In bonded portions between the electrode and ball portions of the gold wires, an interdiffusion of Au and Al is suppressed to prevent the formation of Au4Al after PCT (Pressure Cooker Test). Thus, a desired bonding strength is obtained even when the pitch of the electrode pads is smaller than 65 mum and the diameter of the ball portion is smaller than 55 mum or the diameter of the wire portion of each gold wire is not larger than 25 mum.