Advanced electronics assembly based on direct attachment of semiconductor devices to printed circuit boards is a rapidly growing technology. Direct chip attach (DCA) or flip chip on board (FCOB) processing typically requires application of underfill materials in order to achieve adequate reliability for commercial electronic applications. Unfortunately, flip chip on board processing has yet to become a low cost, high throughput process compatible with high volume surface mount processing. In order for FCOB processing to be SMT compatible, innovative techniques for underfill processing are required. This paper analyzes underfill processing in order to assess manufacturablity in terms of productivity and cost. In particular, four techniques for underfill processing are analyzed including capillary flow, vacuum assisted capillary flow, injection flow, and compression flow processing.