Die to die copper wire bonding enabling low cost 3D packaging

Copper wire replacing gold wire in IC packaging has emerged as a major trend in the packaging industry. The steady and sustained increase in gold (Au) prices in recent years combined with the constant need to reduce the cost of IC packaging is driving this replacement of Au wires with copper (Cu) wires. The maturation of Cu wire is resulting in widespread adoption across many device application and package types. This adoption of Cu wire appears to have invigorated the industry and held off the long predicted demise of wire bonding [1]. The cost benefits associated with converting to Cu wire are being sought for more advanced packaging solutions such as 3D packaging and System in Package (SiP). Such package solutions typically require die to die wire bonding and/or reverse wire bonding, which is closely related. Thus, providing die to die Cu wire bonding capability is an essential step towards enabling the copper wire transition for advanced package types. This paper will highlight the development of die to die wire bonding with Cu wire and will show the results of reliability tests demonstrating the capability of the developed die to die Cu wire bonding package solution.