Method for determining rotational error portion of total misalignment error in a stepper
AssigneeKoninklijke Philips Electronics N.V.
InventorPierre Leroux
Life of this patent
Estimating the term…
Abstract
A method for determining rotational error portion of total misalignment error in a stepper. In one embodiment, the method comprises a series of steps in a stepper, starting with the step of receiving a wafer, having a first pattern and an error-free fine alignment target, in the stepper. In another step, the wafer is aligned in the stepper using the error-free fine alignment target. Then a second pattern is created on the wafer overlaying said first pattern. In another step, the rotational error portion of the total misalignment error is determined by measuring the circumferential misalignment between the first pattern and the second pattern.
Claims12
In a stepper, a method of determining a rotational error portion of a total misalignment error for a wafer, said method comprising the steps of:
- a) receiving said wafer, said wafer having a first pattern, wherein said first pattern is located in an outer region of any shot and a fine alignment target formed therein, said fine alignment target located in a center region of a first shot;
- b) aligning said wafer in said stepper using said fine alignment target;
- c) creating a second pattern on said wafer, said second pattern overlaying said first pattern;
- and
- d) measuring a circumferential misalignment between said first pattern and said second pattern to obtain said rotational error portion of said total misalignment error.
Dependencies are inferred from the claim text.