Techniques for quantifying fin-thickness variation in FINFET technology

A method for optimizing a FINFET fabrication process, the method comprising the steps of:

• quantifying fin thickness variation (ΔDfin) between a pair of long channel FINFET devices by (a) obtaining threshold voltage (Vth) values for each of the long channel FINFET devices in the pair;
• (b) determining a difference in the Vth values (ΔVth) for the pair of long channel FINFET devices, and (c) using the ΔVth to determine the ΔDfin between the pair of long channel FINFET devices, wherein the ΔVth is a function of a difference in a body charge (Qbody) and a gate capacitance between the pair of long channel FINFET devices, and wherein the Qbody is a function of fin thickness (Dfin) and channel doping concentration (Nch) for each of the long channel FINFET devices in the pair, and as such the ΔVth is proportional to the ΔDfin between the pair of long channel FINFET devices;
• comparing the ΔDfin with a specified ΔDfin value;
• and
• based on results from the comparing step, changing one or more parameters of the fabrication process and repeating the quantifying and comparing steps until the ΔDfin is less than the specified ΔDfin value.