A bonding wire for a semiconductor device, characterized in that the bonding wire includes a Cu alloy core material and a Pd coating layer formed on a surface of the Cu alloy core material, the bonding wire contains an element that provides bonding reliability in a high-temperature environment, and a strength ratio defined by the following Equation (1) is 1.1 to 1.6:

Strength ratio=ultimate strength/0.2% offset yield strength.(1)

A bonding wire for a semiconductor device, characterized in that the bonding wire includes a Cu alloy core material and a Pd coating layer formed on a surface of the Cu alloy core material, the bonding wire contains an element that provides bonding reliability in a high-temperature environment, and a strength ratio defined by the following Equation (1) is 1.1 to 1.6:

Strength ratio=ultimate strength/0.2% offset yield strength.(1)

A bonding wire for a semiconductor device includes a Cu alloy core material and a Pd coating layer on a surface of the Cu alloy core material, and contains Ga and Ge of 0.011 to 1.2% by mass in total, which is able 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 0.150 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% by mass, it is able to improve the reliability of the ball bonded part in a high-temperature environment at 175 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.

A bonding wire for a semiconductor device includes a Cu alloy core material and a Pd coating layer on a surface of the Cu alloy core material, and contains Ga and Ge of 0.011 to 1.2% by mass in total, which is able 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 0.150 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% by mass, it is able to improve the reliability of the ball bonded part in a high-temperature environment at 175 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.

The present invention provides a ball forming method for forming a ball portion at a tip of a bonding wire which includes a core material mainly composed of Cu, and a coating layer mainly composed of Pd and formed over a surface of the core material, wherein the ball portion is formed in non-oxidizing atmosphere gas including hydrocarbon which is gas at room temperature and atmospheric pressure, the method being capable of improving Pd coverage on a ball surface in forming a ball at a tip of the Pd-coated Cu bonding wire.

Reliability of a semiconductor device is improved.

A wire bonding step includes a step of exposing a wire and a pad electrode to a reducing gas atmosphere, forming a first hydroxyl layer on a surface of a ball portion, and forming a second hydroxyl layer on a surface of the pad electrode, a first bonding step of temporarily joining the ball portion to the pad electrode through the first hydroxyl layer and the second hydroxyl layer, and after the first bonding step, a step of actually joining the ball portion to the pad electrode by performing a heat treatment on a semiconductor chip and a base material.

A bonding wire for a semiconductor device includes a Cu alloy core material and a Pd coating layer on a surface of the Cu alloy core material, and contains Ga and Ge of 0.011 to 1.2% by mass in total, which is able 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 0.150 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% by mass, it is able to improve the reliability of the ball bonded part in a high-temperature environment at 175 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.

A bonding wire for a semiconductor device includes a Cu alloy core material and a Pd coating layer on a surface of the Cu alloy core material, and contains Ga and Ge of 0.011 to 1.2% by mass in total, which is able 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 0.150 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% by mass, it is able to improve the reliability of the ball bonded part in a high-temperature environment at 175 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.

A semiconductor device having a leadframe including a pad (101) surrounded by elongated leads (110) spaced from the pad by a gap (113) and extending to a frame, the pad and the leads having a first thickness (115) and a first and an opposite and parallel second surface; the leads having a first portion (112) of first thickness near the gap and a second portion (111) of first thickness near the frame, and a zone (114) of reduced second thickness (116) between the first and second portions; the second surface (112a) of the first lead portions is coplanar with the second surface (111a) of the second portions. A semiconductor chip (220) with a terminal is attached the pad. A metallic wire connection (230) from the terminal to an adjacent lead includes a stitch bond (232) attached to the first surface of the lead.

A semiconductor device having a leadframe including a pad (101) surrounded by elongated leads (110) spaced from the pad by a gap (113) and extending to a frame, the pad and the leads having a first thickness (115) and a first and an opposite and parallel second surface; the leads having a first portion (112) of first thickness near the gap and a second portion (111) of first thickness near the frame, and a zone (114) of reduced second thickness (116) between the first and second portions; the second surface (112a) of the first lead portions is coplanar with the second surface (111a) of the second portions. A semiconductor chip (220) with a terminal is attached the pad. A metallic wire connection (230) from the terminal to an adjacent lead includes a stitch bond (232) attached to the first surface of the lead.