Cost Analysis of Flip Chip Assembly Processes: Mass Reflow with Capillary Underfill and Thermocompression Bonding with Nonconductive Paste

Abstract

Many factors affect the selection of the assembly and interconnect processes used to package a die. For example, the size of the die and package, the type of substrate, and the number of IOs all must be considered. In this paper, two processes are compared: a flip chip process using mass reflow with capillary underfill versus a flip chip thermocompression bonding process using nonconductive paste. Activity based cost modeling is used for the analysis. Both of the process flows are presented in detail, then multiple cost comparisons are presented. Examples of the variables that will change are package size, material cost, and equipment cost. In most cases, the bonding and material portions of the process flows are focused on rather than the entire assembly and substrate processes—this allows for a better analysis of particular details. Conclusions are drawn about which design scenarios are suitable for each process flow. Key cost drivers that may affect future cost comparisons as the technologies advance are also indicated.