Copper bonding wires have increasingly been used in semiconductor packages because copper is characterized by high joint reliability in high temperature environments, and has a stable market price compared to gold. In conventional EMCs for copper wires, sulfur components are added to ensure adhesion to lead frames in semiconductor packages in the presence of moisture absorption/reflow, etc. Notably, pyrolysis product of sulfur components can cause connection failure of copper wires at high temperatures.
We have commercialized the first sulfur-free*2 EMC in the industry*1. Proprietary technologies were developed to solve problems that were previously difficult to cope with, namely, preventing corrosion of copper wires and increasing adhesion to lead frames without the addition of sulfur components. This has resulted in improved reflow resistance properties and a long service life (3,000 hours at 175°C). The material will help increase the use of copper wires in semiconductor packages for in-vehicle and industrial applications.
