Fluorescence based thermometry for packaging applications

Methods and apparatus for measuring the temperature of epoxy resin in an electronics package are provided herein. In some embodiments, apparatus for encapsulating an electronics package includes: a process chamber having a chamber body enclosing a processing volume; a substrate support having a support surface for receiving and supporting a substrate for forming an electronics package; and a temperature sensor to measure a temperature of an epoxy resin in an electronics package. The temperature sensor includes: an input apparatus including at least a light source disposed outside the chamber body to provide an excitation light energy to a portion of the epoxy resin; and an output apparatus including at least a signal analyzer disposed outside the chamber body to detect fluorescent light energy emitted by the portion of the epoxy resin and determine a temperature of the epoxy resin based on the excitation light energy and the fluorescent light energy.