As chips evolve toward stacked, heterogeneous assemblies and adopt more complex materials, engineers are grappling with new and often less predictable sources of variation. This is redefining what it means to achieve precision, forcing companies to rethink everything from process control and in-line metrology to materials selection and multi-level testing. In this Semiconductor Engineering article, Promex CEO Dick Otte and COO Dave Fromm discuss considerations for achieving precision in bonding and warpage control.