Bonding wire having a silver alloy core, wire bonding method using the bonding wire, and electrical connection part of semiconductor device using the bonding wire

A bonding wire comprising:

• a wire core including a silver-palladium alloy comprising silver and palladium;
• and
• a coating layer disposed on a sidewall of the wire core, the coating layer including gold,
• wherein the coating layer has a non-uniform thickness,
• wherein a thickness of a thinnest portion of the coating layer is 50 nm or more, and
• wherein a thickness of a thickest portion of the coating layer is 200 nm or less,
• wherein the bonding wire further comprises a free air ball formed on one end thereof, and
• wherein the free air ball has an eccentricity, defined as a difference between a length of a long axis thereof and a length of a short axis thereof divided by the length of the short axis thereof, that is less than 0.25 and greater than 0.

An electrical connection part of a semiconductor device, comprising:

• a device including a first pad and a second pad spaced apart from each other;
• and
• a wire structure electrically connecting the first pad to the second pad,
• wherein the wire structure comprises:
• a first bonding portion in contact with the first pad;
• a second bonding portion in contact with the second pad;
• and
• a wire loop connecting the first bonding portion to the second bonding portion,
• wherein the wire loop comprises:
• a wire core including a silver-palladium alloy comprising silver and palladium;
• and
• a coating layer disposed on a sidewall of the wire core,
• wherein a palladium content of the silver-palladium alloy ranges from 0.1 wt % to 1.5 wt %,
• wherein the bonding wire further comprises a free air ball formed on one end thereof, and
• wherein the free air ball has an eccentricity, defined as a difference between a length of a long axis thereof and a length of a short axis there divided by the length of the short axis thereof, that is less than 0.25 and greater than 0.