Monitoring of temperature variation across wafers during processing

A method of measuring temperature across wafers during semiconductor processing, comprising:

• providing a correlation between a peak wafer temperature during a processing step and a change in wafer surface charge or surface potential following said processing step, wherein said providing a correlation comprises processing a thermocouple comprising wafer having a plurality of thermocouples coupled thereto and a control wafer together through said processing step, wherein said thermocouple comprising wafer and said control wafer both comprise a particular layer stack;
• processing a first wafer to be characterized for its peak temperature spatial distribution during said processing step through said processing step;
• measuring said wafer surface charge or surface potential at a plurality of locations on said first wafer following said processing step, and
• determining said peak temperature spatial distribution for said first wafer based on said correlation and said wafer surface charge or surface potential measured in said measuring step.