本发明提供一种接合线，其系于表面具有Pd被覆层之Cu接合线，且改善高温高湿环境下之球接合部之接合可靠性，适合于车载用组件。 于具有Cu合金芯材、及形成于上述Cu合金芯材之表面之Pd被覆层之半导体设备用接合线中，接合线包含合计为0.011~1.2质量%之Ga、Ge。借此，可提升高温高湿环境下之球接合部之接合寿命，改善接合可靠性。较佳为Pd被覆层之厚度为0.015~0.150μm。若接合线进而含有分别为0.011~1.2质量%之Ni、Ir、Pt之1种以上，则可提升175℃以上之高温环境下之球接合部可靠性。又，若于Pd被覆层之表面进而形成包含Au及Pd之合金表皮层，则会改善楔接合性。

There is provided a Cu bonding wire having a Pd coating layer on a surface thereof, that improves bonding reliability of a ball bonded part in a high-temperature, high-humidity environment and is suitable for on-vehicle devices. The bonding wire for a semiconductor device includes a Cu alloy core material and a Pd coating layer formed on a surface of the Cu alloy core material, and the bonding wire contains Ga and Ge of 0.011 to 1.2 pcnt by mass in total. With this configuration, it is ablwe to increase bonding longevity of the ball bonded part in the high-temperature, high-humidity environment, and thus to improve the bonding reliability. The thickness of the Pd coating layer is preferably 0.015 to 0.0150 [mu]m. When the bonding wire further contains one or more elements of Ni, Ir, and Pt in an amount, for each element, of 0.011 to 1.2 pcnt by mass, it is able to improve the reliability of the ball bonded part in a high-temperature environment at 175 DEG C or more. When an alloy skin layer containing Au and Pd is further formed on a surface of the Pd coating layer, wedge bondability improves.