Abstract: Inherent advantages of flip chip technology for reduction in real estate, providing thin profiles, and improvement in speed and performance, played a key role in its application to several industries such as: mainframes, automotive, wireless, and hard disk drive. This paper reports on the application of flip chip in the hard disk drive industry. An excellent prototype method to evaluate initial bumped products is demonstrated by using stud bumping. In this method, a palladium core with solder stud forms the final interconnect bump between the chip and flex substrate. Structural and reliability data are presented. In production, eutectic solder bumps formed by electroplating using the fountain method is implemented. Structural and chemical characterization of the plated bumps are reported. Finally, issues and recommendations related to the assembly of flip chip on flex substrates are discussed.