Methods of in-situ measurements of wafer bow

Various embodiments describe a method of quantifying bow in a wafer. In one embodiment, the method includes measuring a first plurality of distances from a first sensor to a first surface of the wafer to calculate the bow in the wafer. The first sensor is positioned outside of a set of process modules of the plasma processing system. A determination is made whether the calculated bow of the wafer is within a pre-determined range. If the calculated bow of the wafer is within the pre-determined range, the wafer is moved into a process module of the set of process modules for processing and a recipe for processing the wafer is adjusted based on the calculated bow of the wafer. If the calculated bow of the wafer is outside the pre-determined range, the wafer is removed from the plasma processing system. Other methods are described as well.