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 and 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 In of 0.011 to 1.2% by mass and has the Pd coating layer of a thickness of 0.015 to 0.150 μm. With this configuration, it is able to increase the bonding longevity of a ball bonded part in a high-temperature and high-humidity environment, and thus to improve the bonding reliability. When the Cu alloy core material contains one or more elements of Pt, Pd, Rh and Ni in an amount, for each element, of 0.05 to 1.2% by mass, it is able to increase the reliability of a ball bonded part in a high-temperature environment of 175° C. or more. When an Au skin layer is further formed on a surface of the Pd coating layer, wedge bondability improves.

A method comprises heating a first electrically conductive layer that is to be electrically contacted, and that is arranged on a first element, and pressing a first end of a bonding wire on the first electrically conductive layer by exerting pressure to the first end of the bonding wire, and further by exposing the first end of the bonding wire to ultrasonic energy, thereby deforming the first end of the bonding wire and creating a permanent substance-to-substance bond between the first end of the bonding wire and the first electrically conductive layer. The bonding wire either comprises a rounded cross section with a diameter of at least 125 m or a rectangular cross section with a first width of at least 500 m and a first height of at least 50 m.

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 and 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 In of 0.011 to 1.2% by mass and has the Pd coating layer of a thickness of 0.015 to 0.150 m. With this configuration, it is able to increase the bonding longevity of a ball bonded part in a high-temperature and high-humidity environment, and thus to improve the bonding reliability. When the Cu alloy core material contains one or more elements of Pt, Pd, Rh and Ni in an amount, for each element, of 0.05 to 1.2% by mass, it is able to increase the reliability of a ball bonded part in a high-temperature environment of 175 C. or more. When an Au skin layer is further formed on a surface of the Pd coating layer, wedge bondability improves.