Patent ID: 7848839

Claim:
A method, implemented by a computer analysis system programmed to perform the following, comprising: receiving, by the computer analysis system, a user input, wherein the user input defines a threshold to indicate a transition between a dielectric anti-reflective coating film layer and an adjacent low-k film layer; initializing, by the computer analysis system, a timer coupled to the computer analysis system for time to commence at an initial value corresponding to a time of a tool starting a process; receiving, by the computer analysis system, data from a detector coupled to the computer analysis system, the data comprising an intensity of at least one reflected light that is measured by the detector for at least two points in time; storing, by the computer analysis system, the data from the detector in memory coupled to the computer analysis system; plotting, by the computer analysis system, a graphical representation of the data as a function of time using the stored data; determining, by the computer analysis system, whether a slope calculated from the graphical representation meets the threshold; and sending, by the computer analysis system, a signal to the tool based on a determination that the calculated slope meets the threshold, the signal instructing the tool to terminate the process.