Investigation of Layer Characteristics and Reliability of Electroless Palladium and Autocatalytic Gold (IMPACT 2019)

The development of nano-scale surface finishes over copper pads such as Electroless Palladium and Autocatalytic Gold (EPAG) has been evolved in the recent years due to ever increasing demands in terms of reliability, component miniaturization and signal transmission.Scope of this paper is a full investigation of the layer characteristics and reliability of Electroless Palladium and Autocatalytic Gold. As soldering and bonding are of special interest in the microelectronics industry, the solder joint reliability (SJR) and bonding results will be evaluated. This article will further show the grain characteristics of the intermediate palladium to draw conclusions about its reliability.The palladium layer structure was investigated via electronbackscatter diffraction (EBSD) investigation by means of field emission scanning electron microscopy after preparation with focused ion beam (FIB). The results allow an interpretation of the crystallinity and density of the layer.Increasing I/O counts have led to ever decreasing cross sectional contact areas or, by default, an increase in solder performance expectations. The evaluation of high solder joint reliability demands can be satisfied by high speed shear testing (HSS). For those tests semi-autocatalytic gold was used for activation beneath immersionpalladium. Both pretreated layer systems were compared in their achieved shear energies and therefore SJR.To examine EPAGs bonding abilities the as-received (ASR) mode as well as the aged condition at 175°C for 16h were applied.