This paper compares several methods of flip chip assembly suitable for complex high-density micro-systems and discusses the advantages and disadvantages of each, based on our results in eight years of flip chip development and production. Flip chip advantages over other chip interconnection methods include smaller size, better electrical performance, and greater ruggedness. Many new methods of flip chip assembly have become available as alternatives to the venerable solder bump flip chip technology. These newer methods offer finer pitch connections, lower temperature processing, and more design flexibility than the older solder bump approach. In particular, the stud bump/adhesive flip chip method allows assemblies starting from individual die, rather than requiring full wafers. This singulated chip approach is more economical, faster to implement and modify, and avoids the `known good die' problems inherent in wafer-based flip chip processes. Stud bump flip chip, as described here, permits easy prototyping and micro-scale breadboarding during development, and rapid transition to production.