Determining thermal profiles of semiconductor structures

A method using an emitting layer on at a surface of a semiconductor structure, the method comprising:

• performing a reflow process that heats the semiconductor structure according to a temperature profile to cause a controlled collapse chip connection to transform from a solid state to a liquid state;
• during the reflow process, sensing, by one or more computer processors, emission from the emitting layer for a first predetermined time period;
• determining, by one or more computer processors, a first luminescent intensity value of the emitting layer over the first predetermined time period;
• during the reflow process, sensing, by one or more computer processors, emission from the emitting layer for a second predetermined time period;
• determining, by one or more computer processors, a second luminescent intensity value of the emitting layer over a second predetermined time;
• and
• determining, by one or more computer processors, a thermal profile of the surface of the semiconductor structure utilizing the first luminescent intensity value of the emitting layer and the second luminescent intensity value of the emitting layer.