Cost and Yield Comparison of Wafer-to-Wafer, Die-to-Wafer, and Die-to-Die Bonding

There are multiple process options and technologies to consider when creating a product that requires 3D integration. Bonding two wafers (or two die) can be accomplished in various ways, such as with thermocompression, fusion, or adhesive bonding. However, the best assembly process cannot be determined by only studying the pros and cons of the bonding technology itself. There are also three main process flows to consider when pursuing 3D assembly: wafer-to-wafer, die-to-wafer, and die-to-die bonding. This paper will compare the cost and yield for each of these process flows, all of which have advantages and disadvantages depending on the application. Activity based cost modeling will be used to construct three basic process flows, one for each bonding option. The process flows will each be divided into a series of activities, and the total cost of each activity will be accumulated. A variety of cost and yield trade-offs will be conducted using these process flows. The variables the trade-offs will focus o...