As integrated devices continue to shrink in size and increase in speed and complexity, greater consideration must be given to factors such as thermal management at the device level. For many device technologies, thermal management is an important, yet ancillary, factor that may affect device performance and lifetime. For other technologies, such as phase change memory or heat assisted magnetic recording, proper management of heat flow is integral to the functionality of the device. Tighter thermal budgets and design specifications increase the need for an in-fab measurement of material and stack thermal properties.
Time Domain Thermoreflectance (TDTR) is a well-established and powerful technique capable of providing in-plane and through-plane heat flow information for thin films and stacks. The technique uses an experimental setup which is very similar to the Picosecond Laser Acoustics (PLA) system in use by many IDMs for inline measurement of opaque film thickness. In this paper we introduce the logical extension of TDTR capability to the PULSE family of inline PLA metrology tools. We describe the TDTR technique and the basic hardware modifications and modeling algorithms which enable TDTR. We then present benchmark measurements demonstrating the capability and discuss use cases.