Reticle for determining rotational error
AssigneeNXP B.V.
InventorPierre Leroux
Life of this patent
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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.
Claims14
A reticle adaptable for determining a rotational error portion of a total misalignment error, said reticle comprising:
- a first pattern, said first pattern located in a center region of said reticle, said first pattern including a fine alignment target;
- and
- a second pattern, said second pattern located in an outer region of said reticle, said second pattern and said first pattern adaptable to form overlaying images in a wafer for measuring said rotational error portion of a total misalignment error.
An arrangement for determining a rotational error portion of a total misalignment error on a wafer, the arrangement comprising:
- a stepper that includes a light source, masking blades, a lens and a stage;
- and
- a reticle having
- a first pattern located in a center region of the reticle, the first pattern including a fine alignment target, and
- a second pattern located in an outer region of the reticle, wherein the second pattern and the first pattern form overlaying images in the wafer for measuring the rotational error portion of the total misalignment error.
Dependencies are inferred from the claim text.