Patent ID: 7972969
Filing Date: 2011-07-05
Classification: H01L

Abstract:
1. A method for controlling substrate thickness, comprising: dispensing at least one etchant from at least one dispenser to a plurality of different locations on a surface of a spinning substrate to perform etching, the dispensing step including moving a single dispenser among the plurality of different locations; measuring a distance representative of a thickness of the spinning substrate at the plurality of locations, so that the distance representative of the thickness of the substrate is measured at each individual location while dispensing the etchant at that location; and controlling a respective amount of etching performed at each individual location, based on the respective measured distance representative of thickness at that location, wherein the moving step includes moving the dispenser at a first rate while the dispenser is dispensing etchant at a first location on the surface at which the substrate has a first thickness, and moving the dispenser at a second rate while the dispenser is dispensing etchant at a second location on the surface at which the substrate has a second thickness, wherein the first rate is less than the second rate, and the first thickness is greater than the second thickness.