What are the observed errors in x and y (in µm) at the top, bottom, left, right edges, and center of a 4-inch Si wafer?
The observed errors in x and y (in µm) at the top, bottom, left, right edges, and center of a 4-inch Si wafer are as follows:
Top (T): 0.0 µm
Right (R): 0.7 µm
Center (C): 0.5 µm
Left (L): 0.3 µm
Bottom (B): 1.0 µm
X-axis: 0.7 µm
Y-axis: 1.0 µm
Types of Misalignments:
Overlay Errors Representation:
The ϑ (overlay errors) in the 4-inch Si wafer represent various types of misalignments, including in/out error, rotational misalignment, and translational misalignment.
In/Out Error:
Definition:
In/out error refers to the change in position of the overlay along the y-axis. It indicates the discrepancy in alignment between different points on the wafer.
Example:
For instance, the point at the bottom edge of the wafer experiences an in/out error of 0.3 µm.
Rotational Misalignment:
Definition:
Rotational misalignment is determined by observing any changes in the orientation of the overlay. It indicates the angular misalignment between different points.
Observation:
By taking the center point as the reference, the left and right edges of the wafer show a slight rotational misalignment based on the recorded errors.
Translational Misalignment:
Definition:
Translational misalignment refers to a uniform shift in position across all points on the wafer. It signifies the positional discrepancy of the overlay.
Observation:
There is a noticeable translational misalignment across all edges and the center of the wafer, indicated by the uniform positional shift.
Conclusion:
The quantification of in/out, rotational, and translational misalignments is crucial for ensuring the accuracy and reliability of the semiconductor manufacturing process.