1. A method for wet-etching a wafer according to a customized arm scan profile using a wafer wet etching processing system that includes a plurality of stations, the method comprising the steps of: providing, at a process controller including a memory and a processor configured by executing instructions in the form of code therein, a wafer profile defining a target thickness of the wafer at each of a plurality of radial locations on a surface of the wafer after a first etching step and an initial thickness of the wafer at each of the plurality of radial locations; identifying, with the processor, a characteristic variation in thickness across each of the plurality of radial locations, wherein the variation in thickness is determined based on a respective difference between the measured initial thickness and the target thickness of the wafer at each of the plurality of radial locations; selecting, using the configured processor, an arm scan profile according to the identified characteristic variation in thickness across each of the plurality of radial locations; displaying, by the processor on a display, an interactive graphical representation of the arm-scan profile, wherein the arm scan profile is represented as a chart including a plurality of points each of which has a respective first value on a first axis that corresponds to a respective radial location parameter and a respective second value on a second axis that corresponds to a respective arm scan speed parameter at the respective radial location of the plurality of radial locations; receiving at the processor, a user interaction with a particular point on the graphical representation of the arm scan profile, wherein the user interaction includes a manipulation of one or more of the respective first value and the respective second value for the particular point; updating, with the processor according to the manipulation of the one or more of the respective first value and the respective second value for the particular point, one or more of the respective radial location parameter and the arm scan speed parameter in the arm scan profile; and etching the wafer using the wafer wet etching apparatus according to the updated arm scan profile, wherein the arm scan profile controls movement of the arm during the first etching step causing a nozzle to selectively dispense a first etchant onto each of the plurality of radial locations thereby selectively thinning the wafer at each radial location.